@import"https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap";.header{position:sticky;top:0;z-index:100;height:var(--header-height);background:var(--bg-glass);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-bottom:1px solid var(--border-color)}.header-container{max-width:1400px;margin:0 auto;padding:0 24px;height:100%;display:flex;align-items:center;justify-content:space-between;gap:32px}.header-logo{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--text-primary)}.logo-icon{width:36px;height:36px;display:flex;align-items:center;justify-content:center;background:var(--accent-gradient);border-radius:var(--radius-md);color:#fff}.logo-icon svg{width:22px;height:22px}.logo-text{font-size:20px;font-weight:700;background:var(--accent-gradient);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}.logo-img{width:42px;height:42px;object-fit:contain;border-radius:var(--radius-sm);transition:filter var(--transition-fast)}[data-theme=light] .logo-img{filter:brightness(.85) contrast(1.1)}.header-nav{display:flex;align-items:center;gap:8px}.nav-link{padding:8px 16px;font-size:14px;font-weight:500;color:var(--text-secondary);text-decoration:none;border-radius:var(--radius-md);transition:all var(--transition-fast)}.nav-link:hover{color:var(--text-primary);background:var(--bg-tertiary)}.nav-link.active{color:var(--accent-primary);background:var(--bg-tertiary);font-weight:600}.nav-link-admin{color:var(--accent-primary)}.header-actions{display:flex;align-items:center;gap:12px}.theme-toggle svg{width:20px;height:20px}.user-menu{position:relative}.user-avatar-btn{display:flex;align-items:center;gap:10px;padding:6px 12px 6px 6px;background:var(--bg-tertiary);border:1px solid var(--border-color);border-radius:var(--radius-full);cursor:pointer;transition:all var(--transition-fast)}.user-avatar-btn:hover{background:var(--bg-secondary);border-color:var(--border-color-strong)}.user-avatar{width:32px;height:32px;border-radius:50%;background:var(--bg-secondary);object-fit:cover}.user-name{font-size:14px;font-weight:500;color:var(--text-primary)}.chevron{width:16px;height:16px;color:var(--text-tertiary)}.dropdown-menu{position:absolute;top:calc(100% + 8px);right:0;min-width:200px;background:var(--bg-secondary);border:1px solid var(--border-color);border-radius:var(--radius-lg);box-shadow:var(--shadow-xl);padding:8px;z-index:50}.dropdown-item{display:flex;align-items:center;gap:12px;padding:10px 12px;font-size:14px;color:var(--text-primary);text-decoration:none;border-radius:var(--radius-md);cursor:pointer;background:none;border:none;width:100%;transition:all var(--transition-fast)}.dropdown-item svg{width:18px;height:18px;color:var(--text-tertiary)}.dropdown-item:hover{background:var(--bg-tertiary)}.dropdown-item-danger{color:var(--error)}.dropdown-item-danger svg{color:var(--error)}.dropdown-divider{height:1px;background:var(--border-color);margin:8px 0}.auth-buttons{display:flex;align-items:center;gap:8px}.mobile-menu-btn{display:none}.mobile-menu-btn svg{width:24px;height:24px}.mobile-menu-overlay{position:fixed;inset:0;background:#00000080;z-index:200;-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px)}.mobile-menu{position:fixed;top:0;right:0;width:280px;height:100%;background:var(--bg-secondary);padding:24px;display:flex;flex-direction:column;gap:8px;box-shadow:var(--shadow-xl);overflow-y:auto}.mobile-user-info{display:flex;align-items:center;gap:12px;padding:16px;background:var(--bg-tertiary);border-radius:var(--radius-lg);margin-bottom:16px}.mobile-avatar{width:48px;height:48px;border-radius:50%;object-fit:cover}.mobile-user-info span{font-weight:600;font-size:16px;color:var(--text-primary)}.mobile-nav-link{display:flex;align-items:center;gap:14px;padding:14px 16px;font-size:16px;font-weight:500;color:var(--text-primary);text-decoration:none;border-radius:var(--radius-md);border:none;background:none;cursor:pointer;width:100%;transition:all var(--transition-fast)}.mobile-nav-link svg{width:22px;height:22px;color:var(--text-secondary)}.mobile-nav-link:hover{background:var(--bg-tertiary)}.mobile-nav-primary{background:var(--accent-gradient);color:#fff}.mobile-nav-primary svg{color:#fff}.mobile-nav-primary:hover{opacity:.9}.mobile-nav-logout{color:var(--error)}.mobile-nav-logout svg{color:var(--error)}.mobile-nav-divider{height:1px;background:var(--border-color);margin:12px 0}@keyframes slideIn{0%{transform:translate(100%)}to{transform:translate(0)}}.animate-slide-in{animation:slideIn .3s ease-out}.desktop-only{display:flex}@media(max-width:768px){.desktop-only{display:none!important}.mobile-menu-btn{display:flex}.header-container{padding:0 16px}}.course-card{display:flex;flex-direction:column;background:var(--bg-card);-webkit-backdrop-filter:blur(20px);backdrop-filter:blur(20px);border:1px solid var(--border-color);border-radius:var(--radius-lg);overflow:hidden;text-decoration:none;color:inherit;transition:all var(--transition-normal);opacity:0}.course-card:hover{transform:translateY(-8px);box-shadow:var(--shadow-xl);border-color:var(--accent-primary)}.course-thumbnail{position:relative;height:180px;overflow:hidden}.course-thumbnail img{width:100%;height:100%;object-fit:cover;transition:transform var(--transition-slow)}.course-card:hover .course-thumbnail img{transform:scale(1.1)}.course-overlay{position:absolute;inset:0;background:linear-gradient(to top,rgba(0,0,0,.6) 0%,transparent 50%);display:flex;align-items:flex-end;padding:16px}.course-category{padding:4px 12px;font-size:12px;font-weight:600;color:#fff;background:var(--accent-gradient);border-radius:var(--radius-full)}.course-content{flex:1;display:flex;flex-direction:column;padding:20px}.course-title{font-size:18px;font-weight:600;color:var(--text-primary);margin-bottom:8px;line-height:1.3}.course-description{font-size:14px;color:var(--text-secondary);line-height:1.5;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;margin-bottom:16px}.course-meta{margin-bottom:16px}.content-badges{display:flex;flex-wrap:wrap;gap:8px}.content-badge{display:inline-flex;align-items:center;gap:4px;padding:4px 10px;font-size:12px;background:var(--bg-tertiary);border-radius:var(--radius-full);color:var(--text-secondary)}.course-footer{display:flex;align-items:center;justify-content:space-between;margin-top:auto;padding-top:16px;border-top:1px solid var(--border-color)}.course-author{display:flex;align-items:center;gap:8px;font-size:13px;color:var(--text-secondary)}.course-author svg{width:16px;height:16px}.course-arrow{width:32px;height:32px;display:flex;align-items:center;justify-content:center;border-radius:50%;background:var(--bg-tertiary);color:var(--text-secondary);transition:all var(--transition-fast)}.course-arrow svg{width:18px;height:18px}.course-card:hover .course-arrow{background:var(--accent-primary);color:#fff;transform:translate(4px)}.home-page{min-height:100vh}.hero{position:relative;min-height:calc(100vh - var(--header-height));display:flex;flex-direction:column;align-items:center;justify-content:center;padding:60px 24px;overflow:hidden}.hero-background{position:absolute;inset:0;overflow:hidden;z-index:-1}.hero-orb{position:absolute;border-radius:50%;filter:blur(100px);opacity:.5;animation:float 6s ease-in-out infinite}.hero-orb-1{width:600px;height:600px;background:var(--accent-primary);top:-200px;right:-100px;animation-delay:0s}.hero-orb-2{width:500px;height:500px;background:var(--accent-secondary);bottom:-150px;left:-100px;animation-delay:2s}.hero-orb-3{width:400px;height:400px;background:#ec4899;top:50%;left:50%;transform:translate(-50%,-50%);animation-delay:4s;opacity:.3}.hero-content{text-align:center;max-width:800px;z-index:1}.hero-badge{display:inline-flex;align-items:center;gap:8px;padding:8px 16px;background:var(--bg-glass);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border:1px solid 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var(--border-color);border-radius:var(--radius-xl)}.stat{display:flex;flex-direction:column;align-items:center}.stat-value{font-size:28px;font-weight:700;color:var(--text-primary);background:var(--accent-gradient);-webkit-background-clip:text;-webkit-text-fill-color:transparent}.stat-divider{width:1px;height:40px;background:var(--border-color)}.hero-scroll-indicator{position:absolute;bottom:40px;color:var(--text-tertiary)}.hero-scroll-indicator svg{width:24px;height:24px}.courses-section{padding:80px 0;background:var(--bg-secondary)}.section-header{display:flex;flex-direction:column;gap:32px;margin-bottom:48px}.section-title-wrapper{text-align:center}.section-title{font-size:32px;font-weight:700;color:var(--text-primary);margin-bottom:8px}.section-subtitle{font-size:16px;color:var(--text-secondary)}.courses-filters{display:flex;flex-wrap:wrap;gap:16px;justify-content:center;align-items:center}.search-box{position:relative;width:100%;max-width:320px}.search-box svg{position:absolute;left:16px;top:50%;transform:translateY(-50%);width:20px;height:20px;color:var(--text-tertiary)}.search-input{width:100%;padding:12px 16px 12px 48px;font-family:inherit;font-size:14px;background:var(--bg-primary);border:1px solid var(--border-color);border-radius:var(--radius-full);color:var(--text-primary);transition:all var(--transition-fast)}.search-input:focus{outline:none;border-color:var(--accent-primary);box-shadow:0 0 0 3px var(--accent-glow)}.category-filter{display:flex;flex-wrap:wrap;gap:8px;justify-content:center}.category-btn{padding:8px 16px;font-family:inherit;font-size:13px;font-weight:500;background:var(--bg-primary);border:1px solid var(--border-color);border-radius:var(--radius-full);color:var(--text-secondary);cursor:pointer;transition:all var(--transition-fast)}.category-btn:hover{border-color:var(--accent-primary);color:var(--accent-primary)}.category-btn.active{background:var(--accent-primary);border-color:var(--accent-primary);color:#fff}.courses-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:24px}.empty-state{text-align:center;padding:80px 24px}.empty-icon{font-size:64px;margin-bottom:16px}.empty-state h3{font-size:20px;color:var(--text-primary);margin-bottom:8px}.empty-state p{color:var(--text-secondary)}.features-section{padding:80px 0}.features-section .section-title{text-align:center;margin-bottom:48px}.features-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:24px}.feature-card{padding:32px;background:var(--bg-card);border:1px solid var(--border-color);border-radius:var(--radius-lg);text-align:center;transition:all var(--transition-normal)}.feature-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg);border-color:var(--accent-primary)}.feature-icon{font-size:48px;margin-bottom:16px}.feature-card h3{font-size:18px;font-weight:600;color:var(--text-primary);margin-bottom:8px}.feature-card p{font-size:14px;color:var(--text-secondary);line-height:1.6}.footer{padding:32px 0;border-top:1px solid var(--border-color)}.footer-content{display:flex;flex-direction:column;align-items:center;gap:16px}.footer-brand{display:flex;align-items:center;gap:12px;font-size:18px;font-weight:700;color:var(--text-primary)}.footer-brand .logo-icon{width:32px;height:32px;display:flex;align-items:center;justify-content:center;background:var(--accent-gradient);border-radius:var(--radius-sm);color:#fff}.footer-brand .logo-icon svg{width:18px;height:18px}.footer-logo-img{width:40px;height:40px;object-fit:contain;border-radius:var(--radius-sm);transition:filter var(--transition-fast)}[data-theme=light] .footer-logo-img{filter:brightness(.85) contrast(1.1)}.footer-text{font-size:14px;color:var(--text-tertiary)}.footer-link{color:var(--accent-primary);text-decoration:none;font-weight:500;transition:color .2s ease}.footer-link:hover{color:var(--accent-secondary);text-decoration:underline}@media(max-width:768px){.hero{padding:40px 16px}.hero-stats{flex-direction:column;gap:16px;padding:24px}.stat-divider{width:60px;height:1px}.courses-section{padding:48px 0}.courses-grid{grid-template-columns:1fr}}.note-viewer{padding:32px}.note-content{font-size:16px;line-height:1.8;color:var(--text-primary)}.note-content h1{font-size:28px;font-weight:700;margin:32px 0 16px;color:var(--text-primary)}.note-content h2{font-size:22px;font-weight:600;margin:24px 0 12px;color:var(--text-primary)}.note-content h3{font-size:18px;font-weight:600;margin:20px 0 10px;color:var(--text-primary)}.note-content p{margin-bottom:16px}.note-content strong{font-weight:600;color:var(--text-primary)}.note-content 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p{color:var(--text-secondary);font-size:16px}.pdf-viewer{display:flex;flex-direction:column;gap:16px}.pdf-controls{display:flex;align-items:center;justify-content:center;gap:16px;padding:12px;background:var(--bg-tertiary);border-radius:var(--radius-md);position:sticky;top:0;z-index:10}.page-indicator{font-size:14px;font-weight:500;color:var(--text-secondary);min-width:120px;text-align:center}.pdf-container{display:flex;justify-content:center;overflow-x:auto;padding:16px;background:var(--bg-tertiary);border-radius:var(--radius-md)}.pdf-container canvas{max-width:100%;height:auto;border-radius:var(--radius-sm);box-shadow:0 4px 16px #0000001a}.document-badge{display:inline-flex;align-items:center;gap:8px;padding:8px 16px;background:var(--bg-tertiary);border-radius:var(--radius-full);font-size:14px;font-weight:500;color:var(--text-secondary);margin-bottom:24px}.word-content{background:var(--bg-card);padding:32px;border-radius:var(--radius-md);border:1px solid var(--border-color)}.word-content img{max-width:100%;height:auto;border-radius:var(--radius-sm);margin:16px 0}.word-content table{width:100%;border-collapse:collapse;margin:16px 0}.word-content th,.word-content td{border:1px solid var(--border-color);padding:12px;text-align:left}.word-content th{background:var(--bg-tertiary);font-weight:600}.document-header{display:flex;align-items:center;gap:12px;padding:16px 20px;background:var(--bg-tertiary);border-radius:var(--radius-md);margin-bottom:16px}.document-header .file-icon{font-size:24px}.document-header .file-name{flex:1;font-size:16px;font-weight:600;color:var(--text-primary)}.document-download{display:flex;flex-direction:column;align-items:center;justify-content:center;padding:60px;text-align:center}.document-download h3{margin:0 0 8px;color:var(--text-primary)}.document-download p{margin:0 0 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var(--transition-normal)}.flashcard-container{perspective:1000px;width:100%;max-width:500px;margin-bottom:32px}.flashcard{position:relative;width:100%;height:300px;cursor:pointer;transform-style:preserve-3d}.flashcard-inner{position:relative;width:100%;height:100%;transition:transform .6s cubic-bezier(.4,0,.2,1);transform-style:preserve-3d}.flashcard.flipped .flashcard-inner{transform:rotateY(180deg)}.flashcard-front,.flashcard-back{position:absolute;width:100%;height:100%;backface-visibility:hidden;border-radius:var(--radius-xl);display:flex;flex-direction:column;justify-content:center;align-items:center;padding:32px;text-align:center}.flashcard-front{background:var(--bg-card);border:2px solid var(--border-color);box-shadow:var(--shadow-lg)}.flashcard.known .flashcard-front{border-color:var(--success)}.flashcard-back{background:var(--accent-gradient);transform:rotateY(180deg)}.card-content{flex:1;display:flex;flex-direction:column;justify-content:center;width:100%}.card-label{font-size:12px;font-weight:600;text-transform:uppercase;letter-spacing:1px;margin-bottom:16px;opacity:.7}.flashcard-front .card-label{color:var(--text-secondary)}.flashcard-back .card-label{color:#fffc}.card-content p{font-size:24px;font-weight:600;line-height:1.4;margin:0}.flashcard-front .card-content p{color:var(--text-primary)}.flashcard-back .card-content p{color:#fff}.flip-hint{display:flex;align-items:center;gap:8px;font-size:12px;color:var(--text-tertiary);margin-top:16px}.flip-hint svg{width:16px;height:16px}.flashcard-controls{display:flex;align-items:center;gap:16px;margin-bottom:16px}.flashcard-controls .btn{display:flex;align-items:center;gap:8px}.flashcard-controls .btn svg{width:20px;height:20px}.btn-known{padding:12px 24px;font-family:inherit;font-size:14px;font-weight:500;color:var(--text-secondary);background:var(--bg-tertiary);border:2px solid var(--border-color);border-radius:var(--radius-lg);cursor:pointer;transition:all var(--transition-fast);display:flex;align-items:center;gap:8px}.btn-known:hover{border-color:var(--success);color:var(--success)}.btn-known.active{background:#10b98126;border-color:var(--success);color:var(--success)}.btn-known svg{width:18px;height:18px}.keyboard-hints{display:flex;gap:24px;font-size:12px;color:var(--text-tertiary);padding:12px 20px;background:var(--bg-tertiary);border-radius:var(--radius-full)}.keyboard-hints span{display:flex;align-items:center;gap:6px}@media(max-width:640px){.flashcard-viewer{padding:16px}.flashcard{height:250px}.card-content p{font-size:20px}.flashcard-controls{flex-wrap:wrap;justify-content:center}.keyboard-hints{display:none}}.quiz-viewer{padding:32px}.quiz-empty{padding:48px;text-align:center;color:var(--text-secondary)}.quiz-progress{display:flex;align-items:center;justify-content:space-between;margin-bottom:32px}.progress-dots{display:flex;gap:8px;flex-wrap:wrap}.progress-dot{width:12px;height:12px;border-radius:50%;background:var(--bg-tertiary);border:2px solid var(--border-color);cursor:pointer;transition:all var(--transition-fast)}.progress-dot:hover{border-color:var(--accent-primary)}.progress-dot.active{background:var(--accent-primary);border-color:var(--accent-primary);transform:scale(1.2)}.progress-dot.answered{background:var(--success);border-color:var(--success)}.progress-text{font-size:14px;font-weight:500;color:var(--text-secondary)}.question-card{background:var(--bg-secondary);border-radius:var(--radius-lg);padding:32px;margin-bottom:32px}.question-text{font-size:20px;font-weight:600;color:var(--text-primary);margin-bottom:24px;line-height:1.5}.options-list{display:flex;flex-direction:column;gap:12px}.option-btn{display:flex;align-items:center;gap:16px;padding:16px 20px;background:var(--bg-primary);border:2px solid var(--border-color);border-radius:var(--radius-md);cursor:pointer;text-align:left;transition:all 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