.daily-streak-wrapper{align-items:center;display:inline-flex;position:relative}.daily-streak-btn{border-radius:var(--radius-full);cursor:pointer;color:#f59e0b;white-space:nowrap;background:#f59e0b1a;border:1px solid #f59e0b59;flex-shrink:0;align-items:center;gap:5px;padding:5px 10px;font-size:.8rem;font-weight:700;line-height:1;transition:all .2s;display:inline-flex}.daily-streak-btn:hover{background:#f59e0b2e;border-color:#f59e0b8c;transform:translateY(-1px)}.daily-streak-btn.inactive{border-color:var(--border-subtle);color:var(--text-muted);background:#ffffff0d}.daily-streak-btn.inactive:hover{color:var(--text-primary);border-color:var(--border-medium)}.daily-streak-popover{background:var(--bg-surface-raised);border:1px solid var(--border-medium);border-radius:var(--radius-xl);z-index:1000;-webkit-backdrop-filter:blur(20px);backdrop-filter:blur(20px);width:310px;padding:16px;animation:.18s ease-out fadeIn;position:absolute;top:calc(100% + 10px);right:0;box-shadow:0 20px 40px -10px #0009}.streak-popover-header{border-bottom:1px solid var(--border-subtle);align-items:center;gap:12px;margin-bottom:12px;padding-bottom:12px;display:flex}.streak-icon-box{border-radius:var(--radius-md);color:#f59e0b;background:linear-gradient(135deg,#f59e0b33,#ef444433);flex-shrink:0;justify-content:center;align-items:center;width:42px;height:42px;display:flex}.streak-popover-title{color:var(--text-primary);font-size:.95rem;font-weight:800;line-height:1.2}.streak-popover-sub{color:var(--text-secondary);align-items:center;gap:4px;margin-top:3px;font-size:.75rem;display:flex}.streak-calendar-row{color:var(--text-muted);justify-content:space-between;align-items:center;margin-bottom:8px;font-size:.75rem;font-weight:600;display:flex}.streak-week-grid{grid-template-columns:repeat(7,1fr);gap:6px;margin-bottom:14px;display:grid}.streak-day-cell{border-radius:var(--radius-sm);background:var(--bg-card);border:1px solid var(--border-subtle);color:var(--text-muted);flex-direction:column;align-items:center;gap:4px;padding:6px 2px;font-size:.7rem;font-weight:700;transition:all .2s;display:flex}.streak-day-cell.active{color:#f59e0b;background:#f59e0b26;border-color:#f59e0b}.streak-day-cell.today{border-color:var(--accent-cyan);box-shadow:0 0 8px #38bdf866}.streak-goal-box{background:var(--bg-card);border:1px solid var(--border-subtle);border-radius:var(--radius-md);padding:10px 12px}.streak-goal-header{color:var(--text-primary);justify-content:space-between;margin-bottom:6px;font-size:.75rem;font-weight:700;display:flex}.streak-progress-bar{border-radius:var(--radius-full);background:#ffffff14;height:6px;overflow:hidden}.streak-progress-fill{border-radius:var(--radius-full);background:linear-gradient(90deg,#f59e0b,#ef4444);height:100%;transition:width .3s}.streak-goal-hint{color:var(--text-secondary);margin-top:6px;font-size:.72rem;line-height:1.4}.quiz-catalog-container{max-width:1200px;margin:0 auto;padding:2rem 1.5rem}.quiz-hero-banner{border:1px solid var(--border-medium);border-radius:var(--radius-xl);background:linear-gradient(135deg,#10182df2,#0a0f1dfa);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:2rem;margin-bottom:2.5rem;padding:2.5rem;display:flex;position:relative;overflow:hidden;box-shadow:0 20px 40px -15px #0009}.quiz-hero-content{z-index:2;max-width:680px;position:relative}.quiz-hero-tag{border-radius:var(--radius-full);text-transform:uppercase;letter-spacing:.05em;color:var(--accent-cyan);background:#38bdf81f;border:1px solid #38bdf84d;align-items:center;gap:6px;margin-bottom:1rem;padding:4px 12px;font-size:.75rem;font-weight:800;display:inline-flex}.quiz-hero-title{color:#fff;letter-spacing:-.02em;margin-bottom:.85rem;font-size:2.2rem;font-weight:800;line-height:1.25}.quiz-hero-desc{color:var(--text-secondary);font-size:.96rem;line-height:1.65}.quiz-quick-drill-btn{border-radius:var(--radius-lg);color:#000;cursor:pointer;white-space:nowrap;z-index:2;background:linear-gradient(135deg,#f59e0b,#fbbf24);border:none;justify-content:center;align-items:center;gap:8px;padding:.9rem 1.6rem;font-size:.9rem;font-weight:800;transition:all .2s;display:inline-flex;position:relative;box-shadow:0 8px 20px -4px #f59e0b66}.quiz-quick-drill-btn:hover{transform:translateY(-2px);box-shadow:0 12px 24px -4px #f59e0b8c}.quiz-quick-drill-btn:active{transform:translateY(0)}.quiz-toolbar{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:1.2rem;margin-bottom:2rem;display:flex}.quiz-filter-group{border-radius:var(--radius-full);border:1px solid var(--border-subtle);background:#00000040;flex-wrap:wrap;align-items:center;gap:.4rem;padding:4px;display:flex}.quiz-filter-btn{border-radius:var(--radius-full);color:var(--text-secondary);cursor:pointer;background:0 0;border:none;padding:.5rem 1.1rem;font-size:.82rem;font-weight:600;transition:all .2s}.quiz-filter-btn:hover{color:var(--text-primary);background:#ffffff0d}.quiz-filter-btn.active{background:var(--accent-indigo);color:#fff;box-shadow:0 0 12px #6366f166}.quiz-search-wrapper{background:var(--bg-surface-raised);border:1px solid var(--border-medium);border-radius:var(--radius-full);align-items:center;gap:8px;min-width:260px;padding:.45rem 1rem;display:flex}.quiz-search-input{width:100%;font-size:.85rem;box-shadow:none!important;color:var(--text-primary)!important;background:0 0!important;border:none!important;padding:0!important}.quiz-grid{grid-template-columns:repeat(auto-fill,minmax(340px,1fr));gap:1.5rem;display:grid}.quiz-card{background:var(--bg-card);border:1px solid var(--border-subtle);border-radius:var(--radius-xl);flex-direction:column;justify-content:space-between;padding:1.5rem;transition:all .25s;display:flex;position:relative;overflow:hidden}.quiz-card:hover{border-color:var(--border-hover);background:var(--bg-card-hover);transform:translateY(-4px);box-shadow:0 14px 30px -10px #0009}.quiz-card-header{justify-content:space-between;align-items:flex-start;margin-bottom:1rem;display:flex}.quiz-card-icon{border-radius:var(--radius-lg);border:1px solid var(--border-subtle);background:#ffffff0d;justify-content:center;align-items:center;width:48px;height:48px;display:flex}.quiz-card-count{color:var(--accent-cyan);border-radius:var(--radius-full);background:#38bdf81a;border:1px solid #38bdf840;padding:3px 10px;font-size:.75rem;font-weight:700}.quiz-card-title{color:var(--text-primary);letter-spacing:-.01em;margin-bottom:.4rem;font-size:1.2rem;font-weight:800}.quiz-card-desc{color:var(--text-secondary);-webkit-line-clamp:2;-webkit-box-orient:vertical;flex-grow:1;margin-bottom:1.2rem;font-size:.86rem;line-height:1.55;display:-webkit-box;overflow:hidden}.quiz-card-tags{flex-wrap:wrap;gap:.4rem;margin-bottom:1.25rem;display:flex}.quiz-tag-item{color:var(--text-muted);border:1px solid var(--border-subtle);border-radius:var(--radius-sm);background:#ffffff0a;padding:2px 8px;font-size:.7rem;font-weight:600}.quiz-card-footer{border-top:1px solid var(--border-subtle);justify-content:space-between;align-items:center;gap:.75rem;padding-top:1rem;display:flex}.quiz-start-btn{border-radius:var(--radius-md);color:#fff;background:var(--accent-indigo);cursor:pointer;border:none;flex-grow:1;justify-content:center;align-items:center;gap:6px;padding:.65rem 1.2rem;font-size:.85rem;font-weight:700;transition:all .2s;display:inline-flex}.quiz-start-btn:hover{background:#4f46e5;box-shadow:0 0 14px #6366f180}.quiz-mistakes-btn{border-radius:var(--radius-md);color:#f43f5e;cursor:pointer;background:#f43f5e1f;border:1px solid #f43f5e4d;justify-content:center;align-items:center;gap:4px;padding:.65rem .9rem;font-size:.8rem;font-weight:700;transition:all .2s;display:inline-flex}.quiz-mistakes-btn:hover{background:#f43f5e33}.quiz-arena-container{max-width:820px;margin:0 auto;padding:2rem 1rem}.quiz-arena-top{justify-content:space-between;align-items:center;margin-bottom:1.25rem;display:flex}.quiz-back-btn{border-radius:var(--radius-md);color:var(--text-secondary);border:1px solid var(--border-subtle);cursor:pointer;background:0 0;align-items:center;gap:6px;padding:6px 12px;font-size:.8rem;font-weight:600;transition:all .2s;display:inline-flex}.quiz-back-btn:hover{color:var(--text-primary);border-color:var(--border-medium);background:#ffffff0a}.quiz-arena-badge{align-items:center;gap:8px;display:inline-flex}.quiz-count-tag{font-size:.8rem;font-weight:700;font-family:var(--font-mono);color:var(--text-secondary)}.quiz-topic-tag{color:var(--accent-cyan);border-radius:var(--radius-full);background:#38bdf81a;border:1px solid #38bdf840;padding:2px 10px;font-size:.75rem;font-weight:700}.quiz-progress-bar-container{background:var(--bg-surface-raised);border-radius:var(--radius-full);width:100%;height:6px;margin-bottom:1.5rem;overflow:hidden}.quiz-progress-bar-fill{background:var(--grad-brand);border-radius:var(--radius-full);height:100%;transition:width .3s}.quiz-question-box{background:var(--bg-card);border:1px solid var(--border-subtle);border-radius:var(--radius-xl);box-shadow:var(--shadow-card);margin-bottom:1.5rem;padding:2rem}.quiz-question-meta{justify-content:space-between;align-items:center;margin-bottom:1.25rem;display:flex}.quiz-q-category{text-transform:uppercase;color:var(--text-muted);border-radius:var(--radius-sm);border:1px solid var(--border-subtle);background:#ffffff0d;padding:3px 10px;font-size:.75rem;font-weight:800}.quiz-q-level{border-radius:var(--radius-full);padding:2px 10px;font-size:.75rem;font-weight:700}.quiz-q-level.beginner{color:#10b981;background:#10b9811f;border:1px solid #10b9814d}.quiz-q-level.intermediate{color:#f59e0b;background:#f59e0b1f;border:1px solid #f59e0b4d}.quiz-q-level.advanced{color:#f43f5e;background:#f43f5e1f;border:1px solid #f43f5e4d}.quiz-question-title{color:var(--text-primary);margin-bottom:1.25rem;font-size:1.25rem;font-weight:800;line-height:1.5}.quiz-code-snippet{border:1px solid var(--border-subtle);border-radius:var(--radius-md);font-family:var(--font-mono);color:#38bdf8;background:#080c16;margin-bottom:1.5rem;padding:1rem;font-size:.82rem;line-height:1.5;overflow-x:auto}.quiz-options-grid{flex-direction:column;gap:.75rem;display:flex}.quiz-option-button{text-align:left;border-radius:var(--radius-lg);background:var(--bg-surface-raised);border:1px solid var(--border-subtle);width:100%;color:var(--text-primary);cursor:pointer;justify-content:space-between;align-items:center;gap:1rem;padding:1rem 1.25rem;font-size:.92rem;font-weight:600;transition:all .2s;display:flex}.quiz-option-button:hover:not(:disabled){border-color:var(--border-hover);background:#ffffff0d;transform:translate(3px)}.quiz-option-left{align-items:center;gap:12px;display:flex}.quiz-option-letter{border-radius:var(--radius-full);width:28px;height:28px;color:var(--text-secondary);background:#ffffff14;flex-shrink:0;justify-content:center;align-items:center;font-size:.8rem;font-weight:800;display:flex}.quiz-option-button.correct{box-shadow:0 0 14px #10b98140;color:#a7f3d0!important;background:#10b98126!important;border-color:#10b981!important}.quiz-option-button.correct .quiz-option-letter{color:#000;background:#10b981}.quiz-option-button.wrong{box-shadow:0 0 14px #f43f5e40;color:#fecdd3!important;background:#f43f5e26!important;border-color:#f43f5e!important}.quiz-option-button.wrong .quiz-option-letter{color:#fff;background:#f43f5e}.quiz-option-button.dimmed{opacity:.45}.quiz-explanation-card{border:1px solid var(--border-medium);border-radius:var(--radius-xl);background:#0e1525f2;margin-top:1.5rem;padding:1.5rem;animation:.25s fadeIn}.quiz-explanation-header{color:var(--accent-emerald);align-items:center;gap:8px;margin-bottom:.75rem;font-size:.9rem;font-weight:800;display:flex}.quiz-explanation-text{color:var(--text-secondary);margin-bottom:1rem;font-size:.88rem;line-height:1.6}.quiz-takeaway-box{border-left:3px solid var(--accent-cyan);border-radius:0 var(--radius-md) var(--radius-md) 0;color:#e0f2fe;background:#38bdf814;margin-bottom:1rem;padding:.75rem 1rem;font-size:.82rem}.quiz-retry-notice{border-radius:var(--radius-md);color:#f43f5e;background:#f43f5e1a;border:1px solid #f43f5e40;align-items:center;gap:8px;margin-bottom:1rem;padding:.65rem 1rem;font-size:.8rem;font-weight:600;display:flex}.quiz-next-btn{border-radius:var(--radius-lg);color:#fff;background:var(--accent-indigo);cursor:pointer;border:none;justify-content:center;align-items:center;gap:8px;width:100%;padding:.9rem 1.5rem;font-size:.92rem;font-weight:800;transition:all .2s;display:inline-flex;box-shadow:0 4px 16px #6366f166}.quiz-next-btn:hover{background:#4f46e5;box-shadow:0 6px 20px #6366f18c}.quiz-result-container{max-width:620px;margin:0 auto;padding:2.5rem 1rem}.quiz-result-card{background:var(--bg-card);border:1px solid var(--border-medium);border-radius:var(--radius-xl);text-align:center;box-shadow:var(--shadow-card);padding:2.5rem 2rem;animation:.3s fadeIn}.quiz-result-icon{border-radius:var(--radius-xl);color:#fff;background:linear-gradient(135deg,#f59e0b,#ef4444);justify-content:center;align-items:center;width:72px;height:72px;margin:0 auto 1.5rem;display:flex;box-shadow:0 10px 25px -5px #f59e0b80}.quiz-result-title{color:#fff;letter-spacing:-.01em;margin-bottom:.5rem;font-size:1.75rem;font-weight:800}.quiz-result-subtitle{color:var(--text-secondary);margin-bottom:2rem;font-size:.9rem}.quiz-score-banner{background:var(--bg-surface-raised);border:1px solid var(--border-subtle);border-radius:var(--radius-lg);justify-content:space-around;align-items:center;margin-bottom:2rem;padding:1.5rem 1rem;display:flex}.quiz-score-num{font-size:2.5rem;font-weight:800;font-family:var(--font-mono);color:var(--accent-cyan)}.quiz-score-sub{color:var(--text-muted);text-transform:uppercase;margin-top:4px;font-size:.8rem;font-weight:600}.quiz-stats-grid{grid-template-columns:repeat(2,1fr);gap:1rem;margin-bottom:2rem;display:grid}.quiz-stat-card{background:var(--bg-surface-raised);border:1px solid var(--border-subtle);border-radius:var(--radius-md);text-align:left;padding:1rem}.quiz-stat-label{color:var(--text-muted);align-items:center;gap:6px;margin-bottom:4px;font-size:.75rem;font-weight:600;display:flex}.quiz-stat-value{color:var(--text-primary);font-size:1.1rem;font-weight:700}.quiz-result-buttons{flex-direction:column;gap:.75rem;display:flex}.quiz-primary-action-btn{border-radius:var(--radius-md);color:#fff;background:var(--accent-indigo);cursor:pointer;border:none;justify-content:center;align-items:center;gap:8px;width:100%;padding:.85rem;font-size:.9rem;font-weight:700;transition:all .2s;display:inline-flex}.quiz-primary-action-btn:hover{background:#4f46e5;box-shadow:0 0 14px #6366f166}.quiz-secondary-action-btn{border-radius:var(--radius-md);width:100%;color:var(--text-primary);border:1px solid var(--border-medium);cursor:pointer;background:0 0;justify-content:center;align-items:center;gap:8px;padding:.85rem;font-size:.9rem;font-weight:700;transition:all .2s;display:inline-flex}.quiz-secondary-action-btn:hover{border-color:var(--border-hover);background:#ffffff0d}[data-theme=light] .quiz-hero-banner{background:linear-gradient(135deg,#fff,#f1f5f9);border-color:#0000001a;box-shadow:0 10px 30px -10px #0000001a}[data-theme=light] .quiz-hero-title,[data-theme=light] .quiz-result-title{color:#0f172a}[data-theme=light] .quiz-card{background:#fff;border-color:#00000014}[data-theme=light] .quiz-card:hover{border-color:var(--accent-indigo);background:#fff;box-shadow:0 12px 28px -10px #0000001f}[data-theme=light] .quiz-question-box,[data-theme=light] .quiz-result-card,[data-theme=light] .daily-streak-popover{background:#fff;border-color:#0000001a;box-shadow:0 10px 30px -5px #00000014}[data-theme=light] .quiz-option-button,[data-theme=light] .quiz-score-banner,[data-theme=light] .quiz-stat-card{background:#f8fafc;border-color:#00000014}[data-theme=light] .quiz-code-snippet{color:#38bdf8;background:#0f172a}@media (width<=768px){.quiz-catalog-container{padding:1.25rem 1rem}.quiz-hero-banner{flex-direction:column;align-items:stretch;padding:1.5rem}.quiz-hero-title{font-size:1.6rem}.quiz-toolbar{flex-direction:column;align-items:stretch}.quiz-search-wrapper{width:100%}.quiz-grid{grid-template-columns:1fr}}:root{--font-sans:"Plus Jakarta Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;--font-mono:"JetBrains Mono", "Fira Code", monospace;--bg-page:#050811;--bg-surface:#0a0f1d;--bg-surface-raised:#10172a;--bg-card:#0e1525d9;--bg-card-hover:#141e34f2;--bg-glass:#080d18e6;--border-subtle:#ffffff14;--border-medium:#ffffff24;--border-hover:#38bdf866;--text-primary:#f8fafc;--text-secondary:#94a3b8;--text-muted:#64748b;--accent-cyan:#38bdf8;--accent-indigo:#6366f1;--accent-purple:#a855f7;--accent-emerald:#10b981;--accent-amber:#f59e0b;--accent-rose:#f43f5e;--grad-brand:linear-gradient(135deg, #38bdf8 0%, #6366f1 50%, #a855f7 100%);--grad-brand-subtle:linear-gradient(135deg, #38bdf81f 0%, #6366f11f 100%);--radius-sm:6px;--radius-md:10px;--radius-lg:16px;--radius-xl:22px;--radius-full:9999px;--shadow-card:0 10px 30px -10px #00000080, 0 0 0 1px var(--border-subtle);--shadow-glow-cyan:0 0 20px -3px #38bdf859}[data-theme=light]{--bg-page:#f8fafc;--bg-surface:#fff;--bg-surface-raised:#f1f5f9;--bg-card:#fff;--bg-card-hover:#f8fafc;--bg-glass:#fffffff2;--border-subtle:#00000014;--border-medium:#00000024;--border-hover:#6366f166;--text-primary:#0f172a;--text-secondary:#475569;--text-muted:#94a3b8;--shadow-card:0 4px 20px -4px #00000014, 0 0 0 1px var(--border-subtle)}*,:before,:after{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-sans);background-color:var(--bg-page);color:var(--text-primary);-webkit-font-smoothing:antialiased;background-image:radial-gradient(at 50% 0,#6366f126 0%,#0000 60%),radial-gradient(at 90%,#38bdf80f 0%,#0000 40%),linear-gradient(90deg,#ffffff04 1px,#0000 1px),linear-gradient(#ffffff04 1px,#0000 1px);background-size:100% 100%,100% 100%,40px 40px,40px 40px;min-height:100vh;line-height:1.6;overflow-x:hidden}input,select,textarea{border-radius:var(--radius-md);outline:none;padding:.6rem .9rem;font-family:inherit;font-size:.88rem;transition:border-color .2s,box-shadow .2s;background:var(--bg-surface-raised)!important;color:var(--text-primary)!important;border:1px solid var(--border-medium)!important}input:focus,select:focus,textarea:focus{border-color:var(--accent-cyan)!important;box-shadow:0 0 12px #38bdf840!important}input::placeholder{color:var(--text-muted)}select{cursor:pointer;appearance:auto}button{cursor:pointer;color:inherit;background:0 0;border:none;font-family:inherit}::-webkit-scrollbar{width:6px;height:6px}::-webkit-scrollbar-track{background:0 0}::-webkit-scrollbar-thumb{border-radius:var(--radius-full);background:#ffffff26}::-webkit-scrollbar-thumb:hover{background:#38bdf866}.app-header{z-index:100;background:var(--bg-glass);-webkit-backdrop-filter:blur(16px);border-bottom:1px solid var(--border-subtle);padding:.55rem 1.25rem;position:sticky;top:0}.header-content{justify-content:space-between;align-items:center;gap:1rem;max-width:1440px;margin:0 auto;display:flex}.brand-wrapper{cursor:pointer;-webkit-user-select:none;user-select:none;color:inherit;flex-shrink:0;align-items:center;gap:.65rem;text-decoration:none;display:flex}.brand-icon-box{border-radius:var(--radius-md);background:linear-gradient(135deg,#38bdf833,#6366f140);border:1px solid #38bdf859;flex-shrink:0;justify-content:center;align-items:center;width:34px;height:34px;display:flex;box-shadow:0 0 12px -2px #38bdf859}.brand-text h1{letter-spacing:-.02em;color:var(--text-primary);white-space:nowrap;align-items:center;gap:6px;margin:0;font-size:1.1rem;font-weight:800;display:flex}.brand-title{letter-spacing:-.02em;font-weight:800}.brand-badge{font-size:.62rem;font-family:var(--font-mono);color:var(--accent-cyan);border-radius:var(--radius-full);white-space:nowrap;letter-spacing:.02em;background:#38bdf81f;border:1px solid #38bdf840;padding:2px 7px;font-weight:700;line-height:1.2}.brand-badge-pro{color:#f59e0b;background:linear-gradient(135deg,#f59e0b33,#ea580c33);border-color:#f59e0b73;font-weight:800;box-shadow:0 0 8px #f59e0b40}.nav-tabs{border-radius:var(--radius-full);border:1px solid var(--border-subtle);background:#ffffff08;flex-shrink:0;align-items:center;gap:.25rem;padding:3px 4px;display:flex}.nav-tab-btn{border-radius:var(--radius-full);color:var(--text-secondary);white-space:nowrap;cursor:pointer;background:0 0;border:none;flex-shrink:0;align-items:center;gap:.4rem;padding:.42rem .85rem;font-size:.82rem;font-weight:600;line-height:1;transition:all .15s;display:inline-flex}.nav-tab-btn:hover{color:var(--text-primary);background:#ffffff0f}.nav-tab-btn.active{background:var(--accent-indigo);color:#fff;box-shadow:0 2px 10px #6366f166}.nav-tab-badge-new{color:#fff;letter-spacing:.04em;background:linear-gradient(135deg,#0ea5e9,#6366f1);border-radius:999px;margin-left:2px;padding:1px 5px;font-size:.58rem;font-weight:800;line-height:1.2}.nav-tab-badge-count{font-size:.62rem;font-family:var(--font-mono);color:#f59e0b;background:#f59e0b40;border-radius:999px;padding:1px 5px;font-weight:800;line-height:1.2}.header-actions{flex-shrink:0;align-items:center;gap:.5rem;display:flex}.search-trigger-btn{border-radius:var(--radius-full);border:1px solid var(--border-medium);background:var(--bg-surface-raised);color:var(--text-muted);white-space:nowrap;cursor:pointer;flex-shrink:0;align-items:center;gap:.45rem;padding:.42rem .75rem;font-size:.8rem;line-height:1;transition:all .2s;display:inline-flex}.search-trigger-btn:hover{border-color:var(--accent-cyan);color:var(--text-primary);box-shadow:var(--shadow-glow-cyan)}.icon-btn{border-radius:var(--radius-md);border:1px solid var(--border-medium);background:var(--bg-surface-raised);width:36px;height:36px;color:var(--text-secondary);justify-content:center;align-items:center;transition:all .2s;display:flex}.icon-btn:hover{color:#fff;border-color:var(--accent-cyan)}.main-wrapper{flex:1;width:100%;max-width:1440px;margin:0 auto;padding:1.5rem 1.75rem}.catalog-layout{grid-template-columns:290px 1fr;align-items:start;gap:1.75rem;display:grid}@media (width<=1024px){.catalog-layout{grid-template-columns:1fr}}.sidebar-panel{background:var(--bg-card);border:1px solid var(--border-medium);border-radius:var(--radius-lg);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);box-shadow:var(--shadow-card);flex-direction:column;gap:1.25rem;max-height:calc(100vh - 6.5rem);padding:1.25rem;display:flex;position:sticky;top:5rem}.sidebar-section-title{text-transform:uppercase;letter-spacing:.06em;color:var(--text-muted);justify-content:space-between;align-items:center;margin-bottom:.5rem;font-size:.72rem;font-weight:800;display:flex}.level-pill-group{grid-template-columns:1fr 1fr;gap:.4rem;display:grid}.level-pill-btn{border-radius:var(--radius-md);border:1px solid var(--border-subtle);background:var(--bg-surface);color:var(--text-secondary);text-align:center;justify-content:center;align-items:center;gap:5px;padding:.45rem .6rem;font-size:.78rem;font-weight:700;transition:all .15s;display:flex}.level-pill-btn:hover{background:var(--bg-surface-raised);color:#fff;border-color:var(--border-medium)}.level-pill-btn.active-all{background:var(--accent-indigo);color:#fff;border-color:var(--accent-indigo)}.level-pill-btn.active-beginner{border-color:var(--accent-emerald);color:var(--accent-emerald);background:#10b98133}.level-pill-btn.active-intermediate{border-color:var(--accent-amber);color:var(--accent-amber);background:#f59e0b33}.level-pill-btn.active-advanced{border-color:var(--accent-rose);color:var(--accent-rose);background:#f43f5e33}.sidebar-search-box{margin-bottom:.5rem;position:relative}.sidebar-search-box input{width:100%;padding-left:2rem;font-size:.8rem}.sidebar-search-icon{color:var(--text-muted);pointer-events:none;position:absolute;top:50%;left:.65rem;transform:translateY(-50%)}.category-filter-list{flex-direction:column;flex:1;gap:.25rem;padding-right:4px;display:flex;overflow-y:auto}.category-item-btn{border-radius:var(--radius-md);color:var(--text-secondary);text-align:left;border:1px solid #0000;justify-content:space-between;align-items:center;padding:.55rem .75rem;font-size:.84rem;font-weight:600;transition:all .15s;display:flex}.category-item-btn:hover{color:#fff;background:#ffffff0d}.category-item-btn.active{color:var(--accent-cyan);background:#38bdf81f;border-color:#38bdf84d;font-weight:700}.cat-count-badge{font-size:.68rem;font-family:var(--font-mono);border-radius:var(--radius-full);color:var(--text-muted);background:#ffffff14;padding:2px 6px;font-weight:700}.category-item-btn.active .cat-count-badge{color:var(--accent-cyan);background:#38bdf840}.content-panel{flex-direction:column;gap:1.25rem;display:flex}.category-hero-card{background:var(--bg-card);border:1px solid var(--border-medium);border-radius:var(--radius-lg);box-shadow:var(--shadow-card);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);flex-direction:column;gap:1rem;padding:1.25rem 1.5rem;display:flex}.hero-main-row{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:1rem;display:flex}.hero-title-area{align-items:center;gap:.75rem;display:flex}.hero-title-area h2{letter-spacing:-.02em;color:var(--text-primary);font-size:1.5rem;font-weight:800}.hero-topic-count{font-size:.75rem;font-family:var(--font-mono);border-radius:var(--radius-full);color:#c7d2fe;background:#6366f133;border:1px solid #6366f166;padding:3px 8px;font-weight:700}.in-topic-search-wrap{min-width:260px;position:relative}.in-topic-search-wrap input{border-radius:var(--radius-full);width:100%;padding-left:2rem;font-size:.85rem}.in-topic-search-icon{color:var(--text-muted);pointer-events:none;position:absolute;top:50%;left:.75rem;transform:translateY(-50%)}.hero-controls-row{border-top:1px solid var(--border-subtle);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:.75rem;padding-top:.75rem;display:flex}.hero-stat-chips{flex-wrap:wrap;align-items:center;gap:.5rem;display:flex}.stat-chip{border-radius:var(--radius-full);border:1px solid var(--border-subtle);color:var(--text-secondary);background:#ffffff0d;padding:3px 9px;font-size:.75rem;font-weight:700}.stat-chip.stat-chip-advanced{color:#fda4af;background:#f43f5e26;border-color:#f43f5e59}.subcat-filter-wrap{align-items:center;gap:.5rem;display:flex}.subcat-filter-label{color:var(--text-muted);font-size:.75rem;font-weight:700}.subcat-select-dropdown{max-width:280px;font-weight:600;border-radius:var(--radius-md)!important;padding:.4rem .8rem!important;font-size:.8rem!important}.hero-subcats-row{border-top:1px solid #ffffff14;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:.75rem;padding-top:.85rem;display:flex}.subcat-pills-wrap{flex-wrap:wrap;align-items:center;gap:.45rem;display:flex}.subcat-pill-btn{border-radius:var(--radius-full);color:var(--text-secondary);cursor:pointer;-webkit-user-select:none;user-select:none;background:#ffffff0a;border:1px solid #ffffff17;align-items:center;gap:5px;padding:5px 12px;font-size:.78rem;font-weight:600;transition:all .15s;display:inline-flex}.subcat-pill-btn:hover{color:#fff;background:#ffffff1a;border-color:#ffffff40;transform:translateY(-1px)}.subcat-pill-btn.active{border-color:var(--accent-cyan);color:var(--accent-cyan);background:#38bdf829;font-weight:700;box-shadow:0 0 12px #38bdf840}.subcat-count-tag{font-size:.7rem;font-family:var(--font-mono);opacity:.75}.subcat-select-wrapper{align-items:center;gap:.45rem;margin-left:auto;display:flex}.subcat-dropdown-select{color:#e2e8f0;border-radius:var(--radius-full);cursor:pointer;background:#0f172ae6;border:1px solid #ffffff24;outline:none;max-width:280px;padding:5px 12px;font-size:.78rem;font-weight:600;transition:all .15s}.subcat-dropdown-select:hover,.subcat-dropdown-select:focus{border-color:var(--accent-cyan);box-shadow:0 0 10px #38bdf840}.question-card{background:var(--bg-card);border:1px solid var(--border-medium);border-radius:var(--radius-lg);box-shadow:var(--shadow-card);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);flex-direction:column;gap:.85rem;padding:1.35rem 1.5rem;transition:all .2s;display:flex}.question-card:hover{border-color:var(--border-hover);transform:translateY(-1px);box-shadow:0 12px 30px -8px #000000b3}.card-meta-row{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:.75rem;display:flex}.meta-tags{flex-wrap:wrap;align-items:center;gap:.45rem;display:flex}.tag-badge{border-radius:var(--radius-full);align-items:center;gap:4px;padding:2px 8px;font-size:.72rem;font-weight:700;display:inline-flex}.badge-level-beginner{color:#34d399;background:#10b98126;border:1px solid #10b98159}.badge-level-intermediate{color:#fbbf24;background:#f59e0b26;border:1px solid #f59e0b59}.badge-level-advanced{color:#fda4af;background:#f43f5e2e;border:1px solid #f43f5e66}.badge-category{color:var(--accent-cyan);background:#38bdf81a;border:1px solid #38bdf840}.badge-subcat{color:var(--text-secondary);border:1px solid var(--border-subtle);background:#ffffff0d}.card-action-btns{align-items:center;gap:.5rem;display:flex}.card-lang-toggle{border:1px solid var(--border-medium);border-radius:var(--radius-full);background:#0006;align-items:center;gap:2px;padding:2px;display:inline-flex}.card-lang-toggle .lang-btn{border-radius:var(--radius-full);color:var(--text-muted);padding:3px 9px;font-size:.72rem;font-weight:800;transition:all .15s}.card-lang-toggle .lang-btn:hover{color:#fff}.card-lang-toggle .lang-btn.active{background:var(--accent-cyan);color:#040711;font-weight:800;box-shadow:0 0 8px #38bdf866}.answer-lang-toggle-wrap{align-items:center!important;gap:8px!important;margin-bottom:.75rem!important;display:flex!important}.lang-pill-btn{border-radius:var(--radius-full)!important;background:var(--bg-surface-raised)!important;border:1px solid var(--border-medium)!important;color:var(--text-secondary)!important;align-items:center!important;gap:4px!important;margin-right:6px!important;padding:4px 12px!important;font-size:.75rem!important;font-weight:700!important;display:inline-flex!important}.lang-pill-btn.active{background:var(--accent-cyan)!important;color:#040711!important;border-color:var(--accent-cyan)!important;box-shadow:0 0 10px #38bdf866!important}.mini-action-btn{background:var(--bg-surface);border:1px solid var(--border-subtle);color:var(--text-muted);border-radius:var(--radius-sm);justify-content:center;align-items:center;padding:6px;transition:all .15s;display:flex}.mini-action-btn:hover{background:var(--bg-surface-raised);color:#fff;border-color:var(--border-medium)}.mini-action-btn.bookmarked{border-color:var(--accent-amber);color:var(--accent-amber);background:#f59e0b33}.mini-action-btn.mastered{border-color:var(--accent-emerald);color:var(--accent-emerald);background:#10b98133}.question-title{color:var(--text-primary);font-size:1.12rem;font-weight:700;line-height:1.5}.question-title-en{color:var(--text-muted);margin-top:.15rem;font-size:.88rem;font-style:italic}.expand-answer-btn{border-radius:var(--radius-md);width:100%;color:var(--accent-cyan);background:#38bdf814;border:1px solid #38bdf840;justify-content:space-between;align-items:center;margin-top:.25rem;padding:.7rem 1.1rem;font-size:.85rem;font-weight:700;transition:all .2s;display:flex}.expand-answer-btn:hover{border-color:var(--accent-cyan);background:#38bdf826}.answer-container{border-top:1px solid var(--border-medium);flex-direction:column;gap:1rem;padding-top:1rem;display:flex}.answer-terminal-header{border-radius:var(--radius-sm);border:1px solid var(--border-subtle);background:#00000073;justify-content:space-between;align-items:center;padding:8px 14px;display:flex}.terminal-dots{gap:6px;display:flex}.dot{border-radius:50%;width:10px;height:10px}.dot-red{background:#ef4444}.dot-yellow{background:#f59e0b}.dot-green{background:#10b981}.markdown-body{color:var(--text-secondary);font-size:.95rem;line-height:1.75}.markdown-body p{margin-bottom:.9rem}.markdown-body strong{color:var(--text-primary);font-weight:700}.markdown-body ul,.markdown-body ol{margin-bottom:.9rem;padding-left:1.5rem}.markdown-body li{margin-bottom:.35rem}.markdown-body blockquote{border-left:3px solid var(--accent-cyan);color:#94a3b8;border-radius:0 var(--radius-sm) var(--radius-sm) 0;background:#38bdf80f;margin:.9rem 0;padding:.6rem 1rem}.markdown-body pre{border-radius:var(--radius-md);font-family:var(--font-mono);color:#e2e8f0;margin:.9rem 0;padding:1.1rem;font-size:.85rem;line-height:1.6;overflow-x:auto;background:#030712!important;border:1px solid #ffffff1f!important}.markdown-body code{font-family:var(--font-mono);color:#38bdf8;background:#ffffff14;border:1px solid #ffffff1a;border-radius:4px;padding:2px 6px;font-size:.85em}.markdown-body pre code{color:inherit;background:0 0;border:none;padding:0}.references-box{border-radius:var(--radius-md);border:1px solid var(--border-subtle);background:#0000004d;padding:.8rem 1rem;font-size:.82rem}.references-box span{color:var(--text-muted);margin-right:.5rem;font-weight:700}.ref-link-item{color:var(--accent-cyan);background:#38bdf81a;border:1px solid #38bdf833;border-radius:4px;align-items:center;gap:4px;margin-right:.75rem;padding:2px 7px;text-decoration:none;display:inline-flex}.ref-link-item:hover{text-decoration:underline}.flashcard-view-wrapper{flex-direction:column;align-items:center;gap:1.5rem;max-width:820px;margin:0 auto;display:flex}.flashcard-stats-bar{background:var(--bg-card);border:1px solid var(--border-medium);border-radius:var(--radius-md);justify-content:space-between;align-items:center;width:100%;padding:.75rem 1.25rem;display:flex}.flashcard-perspective-container{perspective:1200px;cursor:pointer;width:100%;height:480px}.flashcard-inner{width:100%;height:100%;transform-style:preserve-3d;border-radius:var(--radius-xl);transition:transform .6s cubic-bezier(.16,1,.3,1);position:relative}.flashcard-inner.flipped{transform:rotateY(180deg)}.flashcard-face{backface-visibility:hidden;border-radius:var(--radius-xl);background:var(--bg-card);border:1px solid #6366f166;flex-direction:column;justify-content:space-between;width:100%;height:100%;padding:2.5rem;display:flex;position:absolute;inset:0;box-shadow:0 20px 50px -10px #000000b3}.flashcard-back{border-color:#38bdf866;overflow-y:auto;transform:rotateY(180deg)}.flashcard-question-text{text-align:center;color:var(--text-primary);margin:auto 0;font-size:1.5rem;font-weight:800;line-height:1.5}.flip-hint{color:var(--text-muted);justify-content:center;align-items:center;gap:6px;font-size:.8rem;display:flex}.flashcard-controls{align-items:center;gap:1rem;display:flex}.btn-flashcard{border-radius:var(--radius-full);align-items:center;gap:8px;padding:.7rem 1.5rem;font-size:.88rem;font-weight:700;transition:all .15s;display:flex}.btn-flashcard-again{color:var(--accent-rose);background:#f43f5e26;border:1px solid #f43f5e66}.btn-flashcard-know{background:var(--accent-emerald);color:#fff}.mock-interview-box{background:var(--bg-card);border:1px solid var(--border-medium);border-radius:var(--radius-xl);max-width:900px;box-shadow:var(--shadow-card);margin:0 auto;padding:2rem}.btn-primary{background:var(--grad-brand);color:#fff;border-radius:var(--radius-full);align-items:center;gap:.5rem;padding:.75rem 1.75rem;font-weight:700;display:inline-flex}.search-modal-backdrop{-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);z-index:200;background:#000000bf;justify-content:center;align-items:flex-start;padding-top:10vh;display:flex;position:fixed;inset:0}.search-modal-card{background:var(--bg-surface);border:1px solid var(--border-medium);border-radius:var(--radius-lg);flex-direction:column;width:100%;max-width:680px;display:flex;overflow:hidden;box-shadow:0 25px 50px -12px #000c}.search-input-wrap{border-bottom:1px solid var(--border-subtle);align-items:center;gap:.75rem;padding:1rem 1.25rem;display:flex}.search-input-wrap input{flex:1;padding:0;font-size:1rem;background:0 0!important;border:none!important}.search-results-list{max-height:480px;padding:.5rem;overflow-y:auto}.search-result-item{border-radius:var(--radius-md);cursor:pointer;flex-direction:column;gap:4px;padding:.75rem 1rem;display:flex}.search-result-item:hover{background:var(--bg-surface-raised)}.category-group-section{margin-bottom:.85rem}.category-group-title{text-transform:uppercase;letter-spacing:.06em;color:var(--text-muted);justify-content:space-between;align-items:center;padding:.35rem .6rem;font-size:.68rem;font-weight:800;display:flex}.cat-item-left{text-overflow:ellipsis;white-space:nowrap;align-items:center;gap:.55rem;display:flex;overflow:hidden}.cat-name-label{text-overflow:ellipsis;white-space:nowrap;overflow:hidden}.badge-level-locked{font-weight:800;color:#f59e0b!important;background:#f59e0b26!important;border:1px solid #f59e0b59!important}.is-locked-card{border-left:3px solid #f59e0b!important}.locked-expand-btn{background:#f59e0b14!important;border-color:#f59e0b40!important}.locked-expand-btn:hover{background:#f59e0b26!important;border-color:#f59e0b73!important}.markdown-locked-teaser{position:relative}.locked-answer-banner{border-radius:var(--radius-md);background:linear-gradient(135deg,#f59e0b1a 0%,#10b9810d 100%);border:1px dashed #f59e0b66;flex-wrap:wrap;align-items:center;gap:1.25rem;margin-top:1rem;padding:1.25rem 1.5rem;display:flex}.locked-icon-circle{background:#f59e0b26;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:48px;height:48px;display:flex}.locked-info{flex:1;min-width:220px}.locked-info h4{color:#f59e0b;margin-bottom:.25rem;font-size:.95rem;font-weight:700}.locked-info p{color:var(--text-secondary);margin:0;font-size:.82rem;line-height:1.4}.locked-upgrade-btn{color:#000;border-radius:var(--radius-md);cursor:pointer;background:linear-gradient(135deg,#f59e0b 0%,#d97706 100%);border:none;align-items:center;gap:.45rem;padding:.65rem 1.15rem;font-size:.88rem;font-weight:700;transition:all .2s;display:flex;box-shadow:0 4px 15px #f59e0b59}.locked-upgrade-btn:hover{transform:translateY(-2px);box-shadow:0 6px 20px #f59e0b80}.nav-upgrade-btn{color:#fff;border-radius:var(--radius-full);cursor:pointer;white-space:nowrap;background:linear-gradient(135deg,#f59e0b 0%,#ea580c 100%);border:none;flex-shrink:0;align-items:center;gap:.35rem;padding:.38rem .85rem;font-size:.8rem;font-weight:700;line-height:1;transition:all .2s;display:inline-flex;box-shadow:0 2px 10px #f59e0b4d}.nav-upgrade-btn:hover{transform:translateY(-1px);box-shadow:0 4px 16px #f59e0b80}.nav-login-btn{background:var(--bg-surface-raised);border:1px solid var(--border-medium);color:var(--text-primary);border-radius:var(--radius-full);cursor:pointer;white-space:nowrap;flex-shrink:0;align-items:center;gap:.35rem;padding:.38rem .8rem;font-size:.8rem;font-weight:600;line-height:1;transition:all .2s;display:inline-flex}.nav-login-btn:hover{background:var(--bg-surface-hover);border-color:var(--accent-cyan)}.user-profile-menu{flex-shrink:0;align-items:center;gap:.35rem;display:inline-flex}.user-avatar-tag{background:var(--bg-surface-raised);border:1px solid var(--border-medium);border-radius:var(--radius-full);white-space:nowrap;cursor:pointer;flex-shrink:0;align-items:center;gap:.4rem;padding:.35rem .65rem;font-size:.8rem;font-weight:600;line-height:1;transition:all .15s;display:inline-flex}.user-avatar-tag:hover{border-color:var(--accent-cyan);background:var(--bg-surface-hover)}.mini-vip-dot{color:#000;letter-spacing:.03em;background:linear-gradient(135deg,#f59e0b,#ea580c);border-radius:999px;padding:1px 5px;font-size:.6rem;font-weight:900;line-height:1.2}.logout-btn{border-radius:var(--radius-full);border:1px solid var(--border-subtle);width:30px;height:30px;color:var(--text-muted);cursor:pointer;background:0 0;flex-shrink:0;justify-content:center;align-items:center;padding:0;transition:all .15s;display:inline-flex}.logout-btn:hover{color:#ef4444;background:#ef444426;border-color:#ef444459}.header-utility-group{background:var(--bg-surface-raised);border:1px solid var(--border-medium);border-radius:var(--radius-full);flex-shrink:0;align-items:center;gap:2px;padding:2px;display:inline-flex}.utility-icon-btn{border-radius:var(--radius-full);width:28px;height:28px;color:var(--text-secondary);cursor:pointer;background:0 0;border:none;justify-content:center;align-items:center;padding:0;transition:all .15s;display:inline-flex}.utility-icon-btn:hover{color:var(--text-primary);background:#ffffff14}.utility-icon-btn .lang-text{color:var(--accent-cyan);font-size:.72rem;font-weight:800}@media (width<=1280px){.header-content{gap:.6rem}.nav-tab-btn{gap:.3rem;padding:.38rem .65rem;font-size:.78rem}.search-trigger-text{display:none}}@media (width<=960px){.nav-tabs{scrollbar-width:none;max-width:50vw;overflow-x:auto}.nav-tabs::-webkit-scrollbar{display:none}}.auth-modal-card{background:var(--bg-card);border:1px solid var(--border-medium);border-radius:var(--radius-lg);flex-direction:column;gap:1.25rem;width:90%;max-width:420px;padding:1.5rem;display:flex;position:relative;box-shadow:0 25px 50px -12px #000000d9}.auth-modal-header{justify-content:space-between;align-items:center;display:flex}.auth-tabs{background:var(--bg-surface-raised);border-radius:var(--radius-md);gap:.5rem;padding:4px;display:flex}.auth-tab{color:var(--text-muted);border-radius:var(--radius-sm);cursor:pointer;background:0 0;border:none;align-items:center;gap:.35rem;padding:.4rem .85rem;font-size:.85rem;font-weight:600;transition:all .2s;display:flex}.auth-tab.active{background:var(--bg-card);color:var(--accent-cyan);box-shadow:0 2px 8px #0006}.auth-close-btn{color:var(--text-muted);cursor:pointer;background:0 0;border:none}.auth-error-banner{color:#ef4444;border-radius:var(--radius-md);background:#ef444426;border:1px solid #ef44444d;align-items:center;gap:.5rem;padding:.65rem .85rem;font-size:.82rem;display:flex}.auth-form{flex-direction:column;gap:1rem;display:flex}.auth-input-group label{color:var(--text-secondary);margin-bottom:.35rem;font-size:.78rem;font-weight:600;display:block}.auth-input-wrap{align-items:center;display:flex;position:relative}.auth-input-icon{color:var(--text-muted);position:absolute;left:.75rem}.auth-input-wrap input{background:var(--bg-surface-raised);border:1px solid var(--border-medium);border-radius:var(--radius-md);width:100%;color:var(--text-primary);padding:.65rem .75rem .65rem 2.4rem;font-size:.9rem}.auth-input-wrap input:focus{border-color:var(--accent-cyan);outline:none}.auth-submit-btn{background:var(--accent-cyan);color:#000;border-radius:var(--radius-md);cursor:pointer;border:none;margin-top:.5rem;padding:.75rem;font-size:.95rem;font-weight:700;transition:all .2s}.auth-submit-btn:hover{filter:brightness(1.1)}.auth-footer{text-align:center;color:var(--text-muted);font-size:.82rem}.auth-footer span{color:var(--accent-cyan);cursor:pointer;font-weight:600}.auth-divider{text-align:center;align-items:center;margin:.75rem 0 .25rem;display:flex}.auth-divider:before,.auth-divider:after{content:"";border-bottom:1px solid var(--border-subtle);flex:1}.auth-divider span{color:var(--text-muted);letter-spacing:.05em;padding:0 10px;font-size:.72rem;font-weight:700}.google-auth-btn{background:var(--bg-surface-raised);border:1px solid var(--border-medium);border-radius:var(--radius-md);width:100%;color:var(--text-primary);cursor:pointer;justify-content:center;align-items:center;gap:.65rem;padding:.68rem 1rem;font-size:.88rem;font-weight:600;transition:all .2s;display:flex}.google-auth-btn:hover{background:var(--bg-surface-hover);border-color:var(--border-hover);transform:translateY(-1px);box-shadow:0 4px 12px #0000004d}.google-btn-container{justify-content:center;width:100%;min-height:40px;display:flex}.upgrade-modal-card{background:var(--bg-card);border:1px solid var(--border-medium);border-radius:var(--radius-lg);width:90%;max-width:860px;max-height:90vh;padding:2rem;position:relative;overflow-y:auto;box-shadow:0 25px 60px -15px #000000e6}.upgrade-header{text-align:center;margin-bottom:1.75rem}.upgrade-badge{color:#f59e0b;background:#f59e0b26;border:1px solid #f59e0b4d;border-radius:999px;align-items:center;gap:.35rem;margin-bottom:.75rem;padding:.3rem .75rem;font-size:.75rem;font-weight:800;display:inline-flex}.upgrade-header h2{color:var(--text-primary);margin-bottom:.5rem;font-size:1.6rem}.upgrade-header p{color:var(--text-secondary);max-width:540px;margin:0 auto;font-size:.9rem}.pricing-grid{grid-template-columns:repeat(auto-fit,minmax(185px,1fr));gap:1rem;margin-bottom:1.75rem;display:grid}.plan-card{background:var(--bg-surface-raised);border:2px solid var(--border-medium);border-radius:var(--radius-lg);cursor:pointer;flex-direction:column;padding:1.25rem;transition:all .2s;display:flex;position:relative}.plan-card:hover{border-color:var(--border-hover);transform:translateY(-2px)}.plan-card.selected{background:#f59e0b0d;border-color:#f59e0b;box-shadow:0 0 25px #f59e0b33}.plan-card.popular{border-color:var(--accent-cyan)}.popular-badge{background:var(--accent-cyan);color:#000;border-radius:999px;padding:2px 8px;font-size:.65rem;font-weight:900;position:absolute;top:-10px;right:12px}.plan-name{margin-bottom:.5rem;font-size:1rem;font-weight:700}.plan-price{color:#f59e0b;margin-bottom:1rem;font-size:1.45rem;font-weight:800}.plan-price span{color:var(--text-muted);font-size:.8rem;font-weight:500}.plan-perks{color:var(--text-secondary);flex-direction:column;gap:.5rem;margin:0;padding:0;font-size:.8rem;list-style:none;display:flex}.plan-perks li{align-items:center;gap:.4rem;display:flex}.upgrade-cta-wrap{flex-direction:column;align-items:center;gap:.75rem;display:flex}.upgrade-action-btn{color:#fff;border-radius:var(--radius-md);cursor:pointer;background:linear-gradient(135deg,#f59e0b 0%,#ea580c 100%);border:none;align-items:center;gap:.5rem;padding:.85rem 2.5rem;font-size:1.05rem;font-weight:800;transition:all .2s;display:flex;box-shadow:0 4px 20px #f59e0b66}.upgrade-action-btn:hover{transform:translateY(-2px);box-shadow:0 6px 25px #f59e0b99}.upgrade-secure-text{color:var(--text-muted);align-items:center;gap:.35rem;font-size:.78rem;display:flex}.payment-body{grid-template-columns:repeat(auto-fit,minmax(280px,1fr));align-items:center;gap:1.5rem;margin-top:1rem;display:grid}.qr-container{border-radius:var(--radius-lg);background:#fff;flex-direction:column;align-items:center;gap:.75rem;padding:1rem;display:flex}.vietqr-img{border-radius:var(--radius-md);width:100%;max-width:240px;height:auto}.qr-status-indicator{color:#0f172a;align-items:center;gap:.4rem;font-size:.8rem;font-weight:600;display:flex}.spin{animation:1.5s linear infinite spin}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.payment-info-box{flex-direction:column;gap:.75rem;display:flex}.info-row{background:var(--bg-surface-raised);border:1px solid var(--border-medium);border-radius:var(--radius-md);justify-content:space-between;align-items:center;padding:.65rem .85rem;font-size:.85rem;display:flex}.info-val.copyable{cursor:pointer;color:var(--accent-cyan);align-items:center;gap:.35rem;display:flex}.info-val.highlight{color:#f59e0b;font-size:1rem;font-weight:800}.highlight-row{background:#f59e0b14;border-color:#f59e0b}.copied-toast{color:#fff;text-align:center;background:#10b981;border-radius:4px;padding:4px 8px;font-size:.75rem;font-weight:700}.demo-simulate-wrap{border-top:1px dashed var(--border-medium);margin-top:.75rem;padding-top:.75rem}.demo-text{color:var(--text-muted);margin-bottom:.4rem;font-size:.75rem}.demo-simulate-btn{border:1px solid var(--accent-cyan);width:100%;color:var(--accent-cyan);border-radius:var(--radius-md);cursor:pointer;background:#38bdf81a;padding:.55rem;font-size:.82rem;font-weight:600;transition:all .2s}.demo-simulate-btn:hover{background:var(--accent-cyan);color:#000}.upgrade-success-view{text-align:center;padding:2rem 1rem}.upgrade-success-icon{margin-bottom:1rem}.tech-explorer-container{border-radius:var(--radius-xl);-webkit-backdrop-filter:blur(20px);backdrop-filter:blur(20px);background:#0f172ab3;border:1px solid #ffffff17;flex-direction:column;gap:1rem;margin-bottom:.5rem;padding:1.35rem 1.6rem;display:flex;box-shadow:0 16px 36px -10px #00000080}.tech-explorer-top{flex-wrap:wrap;justify-content:space-between;align-items:flex-start;gap:1rem;display:flex}.tech-badge-hot{letter-spacing:.04em;color:var(--accent-cyan);border-radius:var(--radius-full);background:#38bdf81f;border:1px solid #38bdf84d;align-items:center;gap:6px;padding:3px 10px;font-size:.68rem;font-weight:800;display:inline-flex}.tech-explorer-heading{letter-spacing:-.02em;color:var(--text-primary);margin:.35rem 0 .2rem;font-size:1.45rem;font-weight:800}.tech-explorer-subtitle{color:var(--text-secondary);margin:0;font-size:.82rem}.explorer-toggle-btn{border-radius:var(--radius-full);color:var(--text-secondary);cursor:pointer;background:#ffffff0d;border:1px solid #ffffff1f;align-items:center;gap:6px;padding:.4rem .85rem;font-size:.78rem;font-weight:600;transition:all .15s;display:inline-flex}.explorer-toggle-btn:hover{color:#fff;background:#ffffff1a;border-color:#ffffff40}.tech-explorer-body{flex-direction:column;gap:1.15rem;display:flex}.role-preset-bar{flex-direction:column;gap:.5rem;display:flex}.preset-label{letter-spacing:.06em;color:var(--text-muted);font-size:.7rem;font-weight:800}.role-pill-row{flex-wrap:wrap;gap:.5rem;display:flex}.role-pill-btn{border-radius:var(--radius-full);color:var(--text-primary);cursor:pointer;background:#ffffff0a;border:1px solid #ffffff17;align-items:center;gap:6px;padding:6px 14px;font-size:.82rem;font-weight:600;transition:all .15s ease-out;display:inline-flex}.role-star-icon{color:#facc15}.role-pill-btn:hover{color:#fff;background:#facc151f;border-color:#facc1566;transform:translateY(-1px)}.role-btn-title{font-weight:700}.role-btn-count{font-size:.72rem;font-family:var(--font-mono);color:var(--text-muted)}.tech-filter-bar{border-top:1px solid #ffffff0f;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:.75rem;padding-top:.75rem;display:flex}.group-tabs-list{flex-wrap:wrap;align-items:center;gap:.35rem;display:flex}.group-tab-btn{border-radius:var(--radius-full);color:var(--text-secondary);cursor:pointer;background:0 0;border:1px solid #0000;align-items:center;gap:5px;padding:5px 12px;font-size:.78rem;font-weight:600;transition:all .15s;display:inline-flex}.group-tab-btn:hover{color:#fff;background:#ffffff0d}.group-tab-btn.active{background:var(--accent-blue);color:#fff;border-color:#38bdf880;box-shadow:0 0 12px #38bdf84d}.tech-search-box{align-items:center;min-width:240px;display:flex;position:relative}.tech-search-box input{border-radius:var(--radius-full);color:#fff;background:#00000059;border:1px solid #ffffff1a;width:100%;height:34px;padding-left:2rem;padding-right:1.75rem;font-size:.8rem}.tech-search-box input:focus{border-color:var(--accent-cyan);outline:none}.tech-search-icon{color:var(--text-muted);pointer-events:none;position:absolute;left:.75rem}.clear-search-btn{color:var(--text-muted);cursor:pointer;background:0 0;border:none;font-size:1rem;line-height:1;position:absolute;right:.65rem}.tech-pills-cloud{flex-wrap:wrap;gap:.5rem;max-height:280px;padding-right:4px;display:flex;overflow-y:auto}.home-tech-pill{color:#e2e8f0;cursor:pointer;-webkit-user-select:none;user-select:none;background:#0f172aa6;border:1px solid #ffffff14;border-radius:12px;align-items:center;gap:8px;padding:7px 14px;transition:all .15s ease-out;display:inline-flex}.home-tech-pill:hover{background:#1e293bd9;border-color:#38bdf873;transform:translateY(-2px);box-shadow:0 6px 14px -3px #0006}.home-tech-pill.active{border-color:var(--accent-cyan);background:#38bdf826;box-shadow:0 0 16px -2px #38bdf866}.pill-name{color:#f1f5f9;font-size:.84rem;font-weight:600}.home-tech-pill.active .pill-name{color:#fff;font-weight:700}.pill-count{color:#94a3b8;font-size:.72rem;font-family:var(--font-mono)}.home-tech-pill.active .pill-count{color:var(--accent-cyan)}.category-brand-icon{filter:drop-shadow(0 1px 2px #00000059);transition:transform .15s}.home-tech-pill:hover .category-brand-icon{transform:scale(1.1)}.no-tech-results{color:var(--text-muted);text-align:center;width:100%;padding:1.5rem;font-size:.85rem}[data-theme=light] body{background-image:radial-gradient(at 50% 0,#6366f112 0%,#0000 60%),radial-gradient(at 90%,#38bdf80a 0%,#0000 40%),linear-gradient(90deg,#00000006 1px,#0000 1px),linear-gradient(#00000006 1px,#0000 1px)}[data-theme=light] .app-header{background:#ffffffeb;border-bottom:1px solid #00000014;box-shadow:0 2px 12px #00000008}[data-theme=light] .nav-tabs{background:#f1f5f9;border-color:#00000014}[data-theme=light] .nav-tab-btn{color:#64748b}[data-theme=light] .nav-tab-btn:hover{color:#0f172a;background:#0000000d}[data-theme=light] .nav-tab-btn.active{color:#fff;background:#2563eb;box-shadow:0 2px 8px #2563eb4d}[data-theme=light] .search-trigger-btn{color:#64748b;background:#f8fafc;border-color:#0000001f}[data-theme=light] .search-trigger-btn:hover{color:#0f172a;border-color:#2563eb;box-shadow:0 0 10px #2563eb26}[data-theme=light] .search-shortcut{color:#64748b;background:#0000000f}[data-theme=light] .icon-btn{color:#475569;background:#f8fafc;border-color:#0000001f}[data-theme=light] .icon-btn:hover{color:#0f172a;background:#f1f5f9;border-color:#2563eb}[data-theme=light] .sidebar-panel{background:#fff;border:1px solid #00000014;box-shadow:0 4px 20px -4px #0000000d}[data-theme=light] .level-pill-btn{color:#475569;background:#f8fafc;border:1px solid #00000014}[data-theme=light] .level-pill-btn:hover{color:#0f172a;background:#f1f5f9;border-color:#00000026}[data-theme=light] .category-item-btn{color:#475569}[data-theme=light] .category-item-btn:hover{color:#0f172a;background:#f1f5f9}[data-theme=light] .category-item-btn.active{color:#1d4ed8;background:#eff6ff;border-color:#93c5fd}[data-theme=light] .cat-count-badge{color:#64748b;background:#0000000f}[data-theme=light] .tech-explorer-container{background:#fff;border:1px solid #00000014;box-shadow:0 10px 30px -8px #0000000f,0 0 0 1px #00000008}[data-theme=light] .tech-badge-hot{color:#0284c7;background:#e0f2fe;border-color:#bae6fd}[data-theme=light] .explorer-toggle-btn{color:#64748b;background:#f8fafc;border:1px solid #00000017}[data-theme=light] .explorer-toggle-btn:hover{color:#0f172a;background:#f1f5f9;border-color:#00000029}[data-theme=light] .role-pill-btn{color:#334155;background:#f8fafc;border:1px solid #00000014}[data-theme=light] .role-pill-btn:hover{color:#854d0e;background:#fef9c3;border-color:#facc15;transform:translateY(-1px)}[data-theme=light] .role-btn-title{color:#1e293b}[data-theme=light] .role-btn-count{color:#64748b}[data-theme=light] .tech-filter-bar{border-top:1px solid #0000000f}[data-theme=light] .group-tab-btn{color:#64748b}[data-theme=light] .group-tab-btn:hover{color:#0f172a;background:#f1f5f9}[data-theme=light] .group-tab-btn.active{color:#fff;background:#2563eb;border-color:#2563eb;box-shadow:0 2px 8px #2563eb4d}[data-theme=light] .tech-search-box input{color:#0f172a!important;background:#f8fafc!important;border:1px solid #0000001f!important}[data-theme=light] .tech-search-box input:focus{border-color:#2563eb!important;box-shadow:0 0 0 3px #2563eb1f!important}[data-theme=light] .home-tech-pill{color:#1e293b;background:#fff;border:1px solid #00000014;box-shadow:0 1px 3px #0000000a}[data-theme=light] .home-tech-pill:hover{background:#f8fafc;border-color:#93c5fd;transform:translateY(-2px);box-shadow:0 6px 14px -3px #00000014}[data-theme=light] .home-tech-pill.active{background:#eff6ff;border-color:#2563eb;box-shadow:0 0 0 1px #2563eb}[data-theme=light] .pill-name{color:#1e293b}[data-theme=light] .home-tech-pill.active .pill-name{color:#1d4ed8}[data-theme=light] .pill-count{color:#64748b}[data-theme=light] .home-tech-pill.active .pill-count{color:#2563eb}[data-theme=light] .category-hero-card{background:#fff;border:1px solid #00000014;box-shadow:0 4px 20px -4px #0000000d}[data-theme=light] .hero-title-area h2,[data-theme=light] .brand-text h1{color:#0f172a!important}[data-theme=light] .hero-subcats-row{border-top:1px solid #0000000f}[data-theme=light] .subcat-pill-btn{color:#475569;background:#f8fafc;border:1px solid #00000014}[data-theme=light] .subcat-pill-btn:hover{color:#0f172a;background:#f1f5f9;border-color:#00000029}[data-theme=light] .subcat-pill-btn.active{color:#1d4ed8;background:#eff6ff;border-color:#2563eb;box-shadow:0 2px 6px #2563eb26}[data-theme=light] .subcat-dropdown-select{color:#0f172a!important;background:#fff!important;border:1px solid #0000001f!important}[data-theme=light] .subcat-dropdown-select:hover,[data-theme=light] .subcat-dropdown-select:focus{border-color:#2563eb!important;box-shadow:0 0 0 3px #2563eb1f!important}[data-theme=light] .in-topic-search-wrap input{color:#0f172a!important;background:#f8fafc!important;border:1px solid #0000001f!important}[data-theme=light] .stat-chip{color:#475569;background:#0000000a;border-color:#00000014}[data-theme=light] .question-card{background:#fff;border:1px solid #00000014;box-shadow:0 4px 16px -2px #0000000d}[data-theme=light] .question-card:hover{border-color:#2563eb59;box-shadow:0 12px 30px -6px #00000017}[data-theme=light] .question-title{color:#0f172a!important}[data-theme=light] .question-title-en{color:#64748b}[data-theme=light] .badge-subcat{color:#475569;background:#0000000a;border-color:#00000014}[data-theme=light] .card-lang-toggle{background:#f1f5f9;border-color:#00000014}[data-theme=light] .card-lang-toggle .lang-btn{color:#64748b}[data-theme=light] .card-lang-toggle .lang-btn:hover{color:#0f172a}[data-theme=light] .card-lang-toggle .lang-btn.active{color:#fff;background:#2563eb;box-shadow:0 2px 6px #2563eb40}[data-theme=light] .mini-action-btn{color:#64748b;background:#f8fafc;border-color:#00000014}[data-theme=light] .mini-action-btn:hover{color:#0f172a;background:#f1f5f9;border-color:#00000029}[data-theme=light] .expand-answer-btn{color:#1d4ed8;background:#eff6ff;border-color:#bfdbfe}[data-theme=light] .expand-answer-btn:hover{background:#dbeafe;border-color:#93c5fd}[data-theme=light] .answer-container{border-top:1px solid #00000014}[data-theme=light] .answer-terminal-header{background:#f8fafc;border-color:#00000014}[data-theme=light] .markdown-body,[data-theme=light] .markdown-body p,[data-theme=light] .markdown-body li,[data-theme=light] .markdown-body span,[data-theme=light] .markdown-body td{color:#1e293b!important}[data-theme=light] .markdown-body strong{font-weight:800;color:#0f172a!important}[data-theme=light] .markdown-body blockquote{color:#1e3a8a;background:#eff6ff;border-left-color:#2563eb}[data-theme=light] .markdown-body code{color:#be185d;background:#f1f5f9;border:1px solid #e2e8f0}[data-theme=light] .references-box{background:#f8fafc;border-color:#00000014}[data-theme=light] .flashcard-face{background:#fff;border-color:#6366f140;box-shadow:0 16px 40px -10px #0000001a}[data-theme=light] .flashcard-question-text{color:#0f172a}[data-theme=light] .search-modal-card,[data-theme=light] .auth-modal-card,[data-theme=light] .upgrade-modal-card{background:#fff;border:1px solid #00000014;box-shadow:0 20px 50px -10px #00000026}[data-theme=light] .search-result-item:hover{background:#f8fafc}[data-theme=light] .plan-card{background:#f8fafc;border-color:#00000014}[data-theme=light] .plan-card:hover{background:#fff;border-color:#2563eb66}[data-theme=light] .plan-card.selected{background:#fffbeb;border-color:#f59e0b}[data-theme=light] .info-row{background:#f8fafc;border-color:#00000014}[data-theme=light] .nav-login-btn{color:#1e293b;background:#f8fafc;border-color:#0000001f}[data-theme=light] .nav-login-btn:hover{background:#f1f5f9;border-color:#2563eb}[data-theme=light] .user-avatar-tag{background:#f8fafc;border-color:#0000001f}.quiz-view-wrapper{min-height:80vh;animation:.3s ease-out fadeIn}@keyframes pulseGlow{0%,to{box-shadow:0 0 15px #f59e0b33}50%{box-shadow:0 0 25px #f59e0b73}}.streak-active-glow{animation:2.5s ease-in-out infinite pulseGlow}[data-theme=light] .quiz-arena .bg-zinc-900\/80,[data-theme=light] .quiz-catalog-container .bg-zinc-900\/60,[data-theme=light] .quiz-result .bg-zinc-900{color:#0f172a!important;background:#fff!important;border-color:#00000014!important}[data-theme=light] .quiz-catalog-container .text-white,[data-theme=light] .quiz-arena .text-white,[data-theme=light] .quiz-result .text-white{color:#0f172a!important}[data-theme=light] .quiz-catalog-container .bg-zinc-900,[data-theme=light] .quiz-arena .bg-zinc-900{background:#f8fafc!important;border-color:#0000001a!important}.floating-support-btn{z-index:900;color:#f8fafc;cursor:pointer;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);background:linear-gradient(135deg,#0f172aeb 0%,#1e293bf2 100%);border:1px solid #38bdf859;border-radius:9999px;align-items:center;gap:8px;padding:10px 18px 10px 14px;font-size:.85rem;font-weight:600;transition:all .25s cubic-bezier(.16,1,.3,1);display:inline-flex;position:fixed;bottom:24px;right:24px;box-shadow:0 8px 24px #00000073,0 0 16px #06b6d433}.floating-support-btn:hover{border-color:var(--accent-cyan);color:#fff;transform:translateY(-3px)scale(1.03);box-shadow:0 12px 30px #0000008c,0 0 24px #06b6d466}.floating-support-pulse{background:#10b981;border-radius:50%;width:8px;height:8px;animation:2s cubic-bezier(0,0,.2,1) infinite supportPing;box-shadow:0 0 #10b981b3}@keyframes supportPing{0%{box-shadow:0 0 #10b981b3}70%{box-shadow:0 0 0 8px #10b98100}to{box-shadow:0 0 #10b98100}}.floating-support-icon{color:var(--accent-cyan);transition:transform .25s}.floating-support-btn:hover .floating-support-icon{transform:rotate(15deg)}.support-modal-card{background:var(--bg-card);border:1px solid var(--border-medium);border-radius:var(--radius-xl);width:100%;max-width:580px;max-height:90vh;box-shadow:var(--shadow-xl), 0 0 40px #06b6d41f;padding:2rem;animation:.25s cubic-bezier(.16,1,.3,1) modalIn;position:relative;overflow-y:auto}.support-header{border-bottom:1px solid var(--border-subtle);align-items:flex-start;gap:1rem;margin-bottom:1.5rem;padding-bottom:1.25rem;display:flex}.support-icon-badge{background:#06b6d41f;border:1px solid #06b6d44d;border-radius:12px;flex-shrink:0;justify-content:center;align-items:center;width:44px;height:44px;display:flex}.support-title{color:var(--text-primary);margin-bottom:.25rem;font-size:1.25rem;font-weight:700}.support-subtitle{color:var(--text-muted);font-size:.82rem;line-height:1.4}.support-channels-section{margin-bottom:1.5rem}.support-section-label{color:var(--text-muted);text-transform:uppercase;letter-spacing:.5px;margin-bottom:.75rem;font-size:.78rem;font-weight:700;display:block}.support-channels-grid{grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:.75rem;display:grid}.support-channel-card{border-radius:var(--radius-md);border:1px solid var(--border-subtle);color:var(--text-primary);cursor:pointer;background:#ffffff08;align-items:center;gap:.75rem;padding:.85rem 1rem;text-decoration:none;transition:all .2s;display:flex}.support-channel-card:hover{border-color:var(--border-medium);background:#ffffff0f;transform:translateY(-1px)}.support-channel-card.zalo{background:#38bdf80f;border-color:#38bdf859}.support-channel-card.zalo:hover{background:#38bdf81f;border-color:#38bdf8}.support-channel-card.tg{background:#60a5fa0f;border-color:#60a5fa59}.support-channel-card.tg:hover{background:#60a5fa1f;border-color:#60a5fa}.support-channel-card.mail{background:#ef44440d;border-color:#ef444440}.support-channel-card.mail:hover{background:#ef44441f;border-color:#ef4444}.support-channel-card .channel-icon-wrap{width:34px;height:34px;color:var(--accent-cyan);background:#ffffff0f;border-radius:8px;flex-shrink:0;justify-content:center;align-items:center;display:flex}.support-channel-card.zalo .channel-icon-wrap{color:#38bdf8;background:#38bdf833}.support-channel-card.tg .channel-icon-wrap{color:#60a5fa;background:#60a5fa33}.support-channel-card.mail .channel-icon-wrap{color:#f87171;background:#ef44442e}.support-channel-card .channel-info{flex-direction:column;flex:1;min-width:0;display:flex}.support-channel-card .channel-name{color:var(--text-primary);font-size:.82rem;font-weight:700}.support-channel-card .channel-val{color:var(--text-muted);white-space:nowrap;text-overflow:ellipsis;font-size:.74rem;overflow:hidden}.support-form{flex-direction:column;gap:1.1rem;display:flex}.support-form-field{flex-direction:column;gap:.4rem;display:flex}.support-field-label{color:var(--text-secondary);font-size:.82rem;font-weight:600}.support-type-pills{grid-template-columns:repeat(2,1fr);gap:.5rem;display:grid}.support-type-btn{border:1px solid var(--border-subtle);border-radius:var(--radius-md);color:var(--text-secondary);cursor:pointer;text-align:left;background:#ffffff08;align-items:center;gap:.5rem;padding:.65rem .85rem;font-size:.8rem;font-weight:500;transition:all .15s;display:inline-flex}.support-type-btn:hover{border-color:var(--border-medium);color:var(--text-primary);background:#ffffff0f}.support-type-btn.active{border-color:var(--accent-cyan);color:var(--accent-cyan);background:#06b6d426;font-weight:600}.support-field-help{color:var(--accent-amber);margin-top:.2rem;font-size:.72rem}.support-textarea{border:1px solid var(--border-medium);border-radius:var(--radius-md);width:100%;color:var(--text-primary);resize:vertical;background:#00000040;outline:none;padding:.75rem 1rem;font-family:inherit;font-size:.85rem;transition:border-color .2s}.support-textarea:focus{border-color:var(--accent-cyan);box-shadow:0 0 0 2px #06b6d426}.support-submit-btn{justify-content:center;align-items:center;gap:.5rem;margin-top:.5rem;padding:.85rem;display:inline-flex}.support-success-view{text-align:center;padding:1.5rem .5rem}.support-success-icon{margin-bottom:1rem;animation:.3s ease-out scaleIn}.support-success-view h2{color:var(--text-primary);margin-bottom:.5rem;font-size:1.35rem;font-weight:700}.support-success-view p{color:var(--text-muted);margin-bottom:1.25rem;font-size:.88rem;line-height:1.5}.support-payment-hint-box{border-radius:var(--radius-md);text-align:left;background:#10b98114;border:1px solid #10b98140;margin-bottom:1rem;padding:1rem}.support-payment-hint-box p{color:var(--text-secondary);margin-bottom:.75rem;font-size:.82rem}.support-quick-direct-btns{gap:.75rem;display:flex}.support-direct-link-btn{color:#fff;border-radius:var(--radius-sm);background:#10b981;align-items:center;gap:.5rem;padding:.6rem 1rem;font-size:.82rem;font-weight:600;text-decoration:none;transition:opacity .2s;display:inline-flex}.support-direct-link-btn.zalo{background:#0284c7}.support-direct-link-btn.tg{background:#2563eb}.support-direct-link-btn:hover{opacity:.9}.upgrade-support-hint{color:var(--text-muted);text-align:center;margin-top:.75rem;font-size:.78rem}.upgrade-support-text-btn{color:var(--accent-cyan);cursor:pointer;background:0 0;border:none;align-items:center;gap:3px;padding:0;font-size:.78rem;font-weight:600;text-decoration:underline;display:inline-flex}.upgrade-support-text-btn:hover{color:#38bdf8}.payment-support-card{border-radius:var(--radius-md);background:#ef44440f;border:1px dashed #ef44444d;justify-content:space-between;align-items:center;gap:1rem;margin-top:1.25rem;padding:.9rem 1.1rem;display:flex}.payment-support-text{color:var(--text-secondary);align-items:center;gap:.6rem;font-size:.78rem;line-height:1.35;display:flex}.payment-support-action-btn{border-radius:var(--radius-sm);color:#f87171;cursor:pointer;white-space:nowrap;background:#ef444426;border:1px solid #ef444459;padding:.5rem .85rem;font-size:.76rem;font-weight:600;transition:all .15s}.payment-support-action-btn:hover{color:#fff;background:#ef4444;border-color:#ef4444}.app-main-footer{border-top:1px solid var(--border-subtle);-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);background:#0a0f1aa6;margin-top:4rem;padding:2.5rem 2rem 2rem}.footer-inner{border-bottom:1px solid var(--border-subtle);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:2rem;max-width:1400px;margin:0 auto;padding-bottom:2rem;display:flex}.footer-left{flex-direction:column;gap:.4rem;max-width:480px;display:flex}.footer-brand{align-items:center;gap:.5rem;display:flex}.footer-logo-box{background:#06b6d41f;border:1px solid #06b6d440;border-radius:6px;justify-content:center;align-items:center;width:26px;height:26px;display:flex}.footer-title{color:var(--text-primary);letter-spacing:-.2px;font-size:.95rem;font-weight:800}.footer-tagline{color:var(--text-muted);font-size:.78rem;line-height:1.4}.footer-actions{flex-wrap:wrap;align-items:center;gap:.75rem;display:flex}.footer-link-btn{border:1px solid var(--border-subtle);border-radius:var(--radius-md);color:var(--text-secondary);cursor:pointer;background:#ffffff0a;align-items:center;gap:.4rem;padding:.5rem .9rem;font-size:.78rem;font-weight:600;text-decoration:none;transition:all .2s;display:inline-flex}.footer-link-btn:hover{border-color:var(--border-medium);color:var(--text-primary);background:#ffffff14;transform:translateY(-1px)}.footer-link-btn.highlight{color:var(--accent-cyan);background:#06b6d41a;border-color:#06b6d44d}.footer-link-btn.highlight:hover{border-color:var(--accent-cyan);background:#06b6d42e}.footer-bottom{max-width:1400px;color:var(--text-muted);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:.75rem;margin:1.5rem auto 0;font-size:.74rem;display:flex}.footer-status-tag{font-family:var(--font-mono);align-items:center;gap:6px;font-size:.72rem;display:inline-flex}.footer-dot-live{background:#10b981;border-radius:50%;width:6px;height:6px;box-shadow:0 0 6px #10b981}[data-theme=light] .floating-support-btn{color:#0f172a;background:#fff;border-color:#0000001f;box-shadow:0 8px 24px #0000001a}[data-theme=light] .floating-support-btn:hover{color:#0284c7;background:#f8fafc;border-color:#0284c7}[data-theme=light] .support-modal-card{background:#fff;border-color:#0000001a}[data-theme=light] .support-channel-card,[data-theme=light] .support-type-btn{background:#f8fafc;border-color:#00000014}[data-theme=light] .support-textarea{color:#0f172a;background:#f8fafc;border-color:#0000001f}[data-theme=light] .app-main-footer{background:#fff;border-top-color:#0000000f}[data-theme=light] .footer-link-btn{color:#475569;background:#f8fafc;border-color:#00000014}:root{--bg-page:#080d19;--bg-surface:#0f1727;--bg-surface-raised:#172137;--bg-card:#111a2ceb;--bg-card-hover:#172238fa;--bg-glass:#080d19db;--border-subtle:#94a3b81f;--border-medium:#94a3b833;--border-hover:#38bdf880;--text-primary:#f4f7fb;--text-secondary:#b3bfd1;--text-muted:#7f8da4;--accent-blue:#4f8cff;--accent-cyan:#4cc9f0;--accent-indigo:#6d72f6;--grad-brand:linear-gradient(135deg, #35bdf1 0%, #6675f5 55%, #8b5cf6 100%);--grad-brand-subtle:linear-gradient(135deg, #35bdf124, #6675f521);--shadow-card:0 18px 48px -30px #000000e6, 0 0 0 1px var(--border-subtle);--shadow-soft:0 18px 55px -34px #000000d9}[data-theme=light]{--bg-page:#f3f6fb;--bg-surface:#fff;--bg-surface-raised:#f1f5fa;--bg-card:#fffffff5;--bg-card-hover:#fff;--bg-glass:#f8fafde6;--border-subtle:#3341551a;--border-medium:#33415529;--border-hover:#2563eb6b;--text-primary:#142033;--text-secondary:#506079;--text-muted:#5f6f86;--accent-blue:#2563eb;--accent-cyan:#0369a1;--accent-indigo:#4f46e5;--grad-brand:linear-gradient(135deg, #0284c7 0%, #4f46e5 58%, #7c3aed 100%);--grad-brand-subtle:linear-gradient(135deg, #0284c717, #4f46e514);--shadow-card:0 14px 40px -28px #0f172a57, 0 0 0 1px var(--border-subtle);--shadow-soft:0 18px 45px -30px #0f172a47}html{scroll-padding-top:5rem}body{background-color:var(--bg-page);background-image:radial-gradient(circle at 10% -8%,#4cc9f01f,#0000 34rem),radial-gradient(circle at 92% 10%,#6d72f61f,#0000 32rem),linear-gradient(#94a3b805 1px,#0000 1px),linear-gradient(90deg,#94a3b805 1px,#0000 1px);background-size:auto,auto,48px 48px,48px 48px}[data-theme=light] body{background-image:radial-gradient(circle at 10% -8%,#0ea5e917,#0000 34rem),radial-gradient(circle at 92% 10%,#6366f114,#0000 32rem),linear-gradient(#33415506 1px,#0000 1px),linear-gradient(90deg,#33415506 1px,#0000 1px);background-size:auto,auto,48px 48px,48px 48px}.app-container{flex-direction:column;min-height:100vh;display:flex}button,a,input,select,textarea{-webkit-tap-highlight-color:transparent}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline-offset:2px;outline:3px solid #4cc9f057}.app-header{background:var(--bg-glass);box-shadow:0 1px 0 var(--border-subtle), 0 12px 40px -30px #000c;padding:.65rem clamp(1rem,2.3vw,2rem)}.header-content,.main-wrapper{max-width:1500px}.brand-icon-box{background:var(--grad-brand-subtle);border-radius:11px;box-shadow:0 8px 24px -12px #4cc9f0cc}.nav-tabs{background:#94a3b80e;border-radius:14px;padding:4px}.nav-tab-btn{border-radius:10px;min-height:34px}.nav-tab-btn.active{background:var(--grad-brand);box-shadow:0 8px 20px -10px #4f46e5e6}.header-actions button,.header-utility-group,.search-trigger-btn{min-height:34px}.mobile-menu-btn{border:1px solid var(--border-medium);background:var(--bg-surface-raised);width:36px;height:36px;color:var(--text-primary);border-radius:10px;justify-content:center;align-items:center;display:none}.main-wrapper{padding:clamp(1rem,2.2vw,2rem) clamp(1rem,2.4vw,2.25rem)}.catalog-layout{grid-template-columns:minmax(250px,282px) minmax(0,1fr);gap:clamp(1rem,2vw,1.75rem)}.sidebar-disclosure,.content-panel{min-width:0}.sidebar-mobile-summary{display:none}.sidebar-panel,.tech-explorer-container,.category-hero-card,.question-card,.flashcard-stats-bar,.mock-interview-box{border-color:var(--border-subtle);box-shadow:var(--shadow-card)}.sidebar-panel{background:color-mix(in srgb, var(--bg-card) 94%, transparent);padding:1.1rem;top:4.8rem}.category-filter-list{padding-right:.3rem}.category-item-btn{border-radius:9px;min-height:39px}.category-item-btn.active{background:var(--grad-brand-subtle);box-shadow:inset 3px 0 0 var(--accent-cyan);border-color:#4cc9f052}.content-panel{gap:1rem}.tech-explorer-container{background:linear-gradient(145deg, #4cc9f00e, transparent 40%), var(--bg-card);border-radius:18px;min-width:0;padding:clamp(1.1rem,2vw,1.5rem);overflow:hidden}.tech-explorer-top,.tech-explorer-title-box,.tech-explorer-body,.tech-filter-bar,.group-tabs-list,.tech-pills-cloud,.hero-main-row,.hero-title-area,.hero-subcats-row,.subcat-pills-wrap{min-width:0}.tech-explorer-heading{font-size:clamp(1.2rem,2.2vw,1.55rem);line-height:1.25}.role-pill-btn,.home-tech-pill,.group-tab-btn,.subcat-pill-btn{min-height:36px}.home-tech-pill{background:color-mix(in srgb, var(--bg-surface-raised) 72%, transparent);border-color:var(--border-subtle)}.pill-name{color:var(--text-primary)}.category-hero-card{background:var(--bg-card);padding:clamp(1rem,2vw,1.35rem) clamp(1rem,2vw,1.5rem);overflow:hidden}.hero-title-area h2{font-size:clamp(1.25rem,2.2vw,1.6rem);line-height:1.25}.question-card{background:var(--bg-card);border-radius:15px;gap:.95rem;padding:clamp(1.05rem,2vw,1.45rem) clamp(1rem,2.2vw,1.55rem)}.question-card:hover{box-shadow:0 22px 50px -34px #000000e6, 0 0 0 1px var(--border-hover)}.question-title{font-size:clamp(1rem,1.7vw,1.12rem);line-height:1.58}.expand-answer-btn{border-radius:10px;min-height:42px}.markdown-body{overflow-wrap:anywhere;font-size:.94rem;line-height:1.75}.markdown-body pre,.markdown-body table{max-width:100%;overflow-x:auto}.answer-container{min-width:0;overflow:hidden}.answer-terminal-header{flex-wrap:wrap;gap:.75rem}.flashcard-view-wrapper,.mock-interview-box{width:min(100%,960px)}.flashcard-perspective-container{width:100%}.search-modal-backdrop{padding:1rem}.search-modal-card,.auth-modal-card,.upgrade-modal-card,.support-modal-card{background:var(--bg-card);border-color:var(--border-medium);max-height:min(90vh,850px);overflow-y:auto;box-shadow:0 28px 90px -30px #000000d9}.app-main-footer{background:color-mix(in srgb, var(--bg-surface) 82%, transparent);margin-top:clamp(2.5rem,6vw,5rem);padding:clamp(2rem,4vw,3rem) clamp(1rem,3vw,2rem) 1.75rem}.footer-inner,.footer-bottom{max-width:1450px}@media (width<=1220px){.brand-badge{display:none}.nav-tab-btn{padding-inline:.55rem}.nav-upgrade-btn span,.user-name-text{display:none}}@media (width<=1024px){html{scroll-padding-top:9rem}.catalog-layout{grid-template-columns:minmax(0,1fr)}.sidebar-disclosure{border:1px solid var(--border-subtle);background:var(--bg-card);box-shadow:var(--shadow-card);border-radius:14px;overflow:hidden}.sidebar-mobile-summary{min-height:52px;color:var(--text-primary);cursor:pointer;justify-content:space-between;align-items:center;gap:1rem;padding:.8rem 1rem;font-size:.86rem;font-weight:750;list-style:none;display:flex}.sidebar-mobile-summary::-webkit-details-marker{display:none}.sidebar-mobile-summary>span:first-child{align-items:center;gap:.55rem;display:inline-flex}.sidebar-mobile-summary:after{content:"+";color:var(--accent-cyan);font-size:1.1rem;line-height:1}.sidebar-disclosure[open] .sidebar-mobile-summary:after{content:"−"}.sidebar-summary-meta{color:var(--text-muted);text-overflow:ellipsis;white-space:nowrap;max-width:45%;margin-left:auto;font-size:.75rem;font-weight:600;overflow:hidden}.sidebar-panel{border:0;border-top:1px solid var(--border-subtle);max-height:390px;box-shadow:none;border-radius:0;position:static}.level-pill-group{grid-template-columns:repeat(4,minmax(0,1fr))}.category-filter-list{min-height:170px}}@media (width<=1100px){.header-content{flex-wrap:wrap}.mobile-menu-btn{display:inline-flex}.nav-tabs{border-radius:12px;order:3;grid-template-columns:repeat(5,minmax(0,1fr));width:100%;max-width:none;padding:.45rem;display:none;overflow:visible}.nav-tabs.mobile-open{display:grid}.nav-tab-btn{justify-content:center;width:100%;min-width:0;padding:.65rem .35rem}.nav-tab-badge-new{display:none}.header-actions{margin-left:auto}.daily-streak-wrapper{display:none}.tech-filter-bar,.hero-main-row{align-items:stretch}.tech-search-box,.in-topic-search-wrap{width:100%;min-width:0}.footer-inner{align-items:flex-start}.footer-actions{width:100%}}@media (width<=700px){.app-header{padding:.55rem .75rem}.brand-wrapper{gap:.5rem}.brand-title{font-size:1rem}.brand-icon-box{width:32px;height:32px}.header-actions{gap:.35rem}.nav-upgrade-btn{display:none}.nav-login-btn{justify-content:center;width:34px;min-width:34px;padding:0}.nav-login-btn span{display:none}.nav-tabs{grid-template-columns:repeat(2,minmax(0,1fr))}.nav-tab-btn:last-child{grid-column:1/-1}.main-wrapper{padding:.85rem .75rem 1.5rem}.catalog-layout,.content-panel{gap:.8rem}.sidebar-mobile-summary{min-height:48px;padding:.7rem .85rem}.sidebar-panel{max-height:440px;padding:.9rem}.level-pill-group{grid-template-columns:repeat(2,minmax(0,1fr))}.tech-explorer-container,.category-hero-card,.question-card,.mock-interview-box{border-radius:13px}.tech-explorer-top{display:grid}.explorer-toggle-btn{justify-content:space-between;width:100%}.role-pill-row,.group-tabs-list,.tech-pills-cloud,.subcat-pills-wrap{scroll-snap-type:x proximity;flex-wrap:nowrap;padding-bottom:.45rem;overflow-x:auto}.role-pill-btn,.group-tab-btn,.home-tech-pill,.subcat-pill-btn{scroll-snap-align:start;flex:none}.tech-pills-cloud{max-height:none;overflow-y:hidden}.hero-title-area{align-items:flex-start}.hero-subcats-row,.subcat-select-wrapper,.subcat-dropdown-select{width:100%;max-width:none}.card-meta-row{align-items:flex-start}.meta-tags{width:100%}.card-action-btns{border-top:1px solid var(--border-subtle);justify-content:flex-end;width:100%;padding-top:.65rem}.tag-badge{max-width:100%}.tag-badge span{text-overflow:ellipsis;overflow:hidden}.expand-answer-btn{text-align:left;padding-inline:.8rem}.answer-terminal-header>div:last-child{width:100%;justify-content:space-between!important}.locked-answer-banner{align-items:flex-start}.locked-upgrade-btn{justify-content:center;width:100%}.flashcard-stats-bar,.flashcard-controls{flex-wrap:wrap;gap:.65rem}.flashcard-stats-bar>div,.flashcard-stats-bar select{width:100%}.flashcard-controls .btn-flashcard{flex:calc(50% - 2.5rem);min-width:0}.flashcard-question-text{font-size:clamp(1.05rem,5vw,1.45rem)}.mock-interview-box{padding:1rem!important}.search-modal-backdrop{align-items:flex-end;padding:0}.search-modal-card,.auth-modal-card,.upgrade-modal-card,.support-modal-card{border-bottom:0;border-radius:18px 18px 0 0;width:100%;max-width:none;max-height:92dvh}.pricing-grid,.support-channels-grid,.payment-body{grid-template-columns:minmax(0,1fr)}.pricing-grid>*,.support-channels-grid>*,.payment-body>*{min-width:0}.upgrade-modal-card,.support-modal-card{padding:1.25rem}.footer-actions{grid-template-columns:repeat(2,minmax(0,1fr));display:grid}.footer-link-btn{text-align:center;justify-content:center}.footer-bottom{flex-direction:column;align-items:flex-start}}@media (width<=420px){.brand-title{text-overflow:ellipsis;max-width:118px;overflow:hidden}.search-trigger-btn,.mobile-menu-btn{justify-content:center;width:34px;min-width:34px;padding:0}.tech-explorer-container,.category-hero-card,.question-card{padding:.9rem}.sidebar-summary-meta{display:none}.footer-actions{grid-template-columns:1fr}}@media (prefers-reduced-motion:reduce){*,:before,:after{scroll-behavior:auto!important;transition-duration:.01ms!important;animation-duration:.01ms!important;animation-iteration-count:1!important}}