@import"https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap";:root{--color-bg-primary: #0d0f14;--color-bg-secondary: #13161e;--color-bg-card: #1a1d27;--color-bg-hover: #22263a;--color-bg-glass: rgba(26, 29, 39, .8);--color-accent: #7c5cfc;--color-accent-hover: #9478ff;--color-accent-glow: rgba(124, 92, 252, .35);--color-accent-muted: rgba(124, 92, 252, .15);--color-success: #22d3a5;--color-warning: #f59e0b;--color-danger: #ef4444;--color-info: #38bdf8;--color-text-primary: #f0f2f8;--color-text-secondary: #8b96b2;--color-text-muted: #4b5473;--color-border: rgba(255, 255, 255, .07);--color-border-active: rgba(124, 92, 252, .5);--radius-sm: 6px;--radius-md: 12px;--radius-lg: 18px;--radius-xl: 24px;--radius-full: 999px;--shadow-sm: 0 2px 8px rgba(0, 0, 0, .3);--shadow-md: 0 4px 20px rgba(0, 0, 0, .4);--shadow-lg: 0 8px 40px rgba(0, 0, 0, .5);--shadow-accent: 0 0 20px var(--color-accent-glow);--transition-fast: .15s ease;--transition-base: .25s ease;--transition-slow: .4s ease;--sidebar-width: 320px;--header-height: 64px}[data-theme=light]{--color-bg-primary: #f4f6fb;--color-bg-secondary: #eaecf4;--color-bg-card: #ffffff;--color-bg-hover: #dde1f0;--color-bg-glass: rgba(244, 246, 251, .85);--color-text-primary: #12152a;--color-text-secondary: #4b5473;--color-text-muted: #8b96b2;--color-border: rgba(0, 0, 0, .08);--color-border-active: rgba(124, 92, 252, .4);--shadow-sm: 0 2px 8px rgba(0, 0, 0, .08);--shadow-md: 0 4px 20px rgba(0, 0, 0, .1);--shadow-lg: 0 8px 40px rgba(0, 0, 0, .12)}*,*:before,*:after{transition:background-color .3s ease,border-color .3s ease,color .3s ease,box-shadow .3s ease}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}html{scroll-behavior:smooth}body{font-family:Inter,system-ui,sans-serif;background-color:var(--color-bg-primary);color:var(--color-text-primary);line-height:1.6;-webkit-font-smoothing:antialiased;overflow-x:hidden}::-webkit-scrollbar{width:6px;height:6px}::-webkit-scrollbar-track{background:var(--color-bg-secondary)}::-webkit-scrollbar-thumb{background:var(--color-text-muted);border-radius:var(--radius-full)}::-webkit-scrollbar-thumb:hover{background:var(--color-accent)}h1,h2,h3,h4,h5,h6{font-weight:700;line-height:1.25;color:var(--color-text-primary)}p{color:var(--color-text-secondary)}a{text-decoration:none;color:inherit}button{cursor:pointer;font-family:inherit}img{display:block;max-width:100%}.app-layout{display:flex;flex-direction:column;height:100vh;overflow:hidden}.main-content{display:flex;flex:1;overflow:hidden;margin-top:var(--header-height)}.header{position:fixed;top:0;left:0;right:0;height:var(--header-height);background:var(--color-bg-glass);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border-bottom:1px solid var(--color-border);display:flex;align-items:center;padding:0 24px;gap:20px;z-index:100}.header-brand{display:flex;align-items:center;gap:10px;flex-shrink:0;text-decoration:none}.brand-logo{width:36px;height:36px;background:linear-gradient(135deg,var(--color-accent),var(--color-accent-hover));border-radius:var(--radius-md);display:grid;place-items:center;font-size:1rem;box-shadow:var(--shadow-accent)}.brand-name{font-size:1.1rem;font-weight:700;background:linear-gradient(135deg,#fff,var(--color-accent-hover));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}.header-course-title{flex:1;font-size:.85rem;font-weight:500;color:var(--color-text-secondary);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;padding:0 12px}.header-course-title span{color:var(--color-text-primary);font-weight:600}.header-progress{display:flex;align-items:center;gap:10px;flex-shrink:0}.progress-bar-container{width:120px;height:6px;background:var(--color-bg-hover);border-radius:var(--radius-full);overflow:hidden}.progress-bar-fill{height:100%;background:linear-gradient(90deg,var(--color-accent),var(--color-success));border-radius:var(--radius-full);transition:width var(--transition-slow)}.progress-text{font-size:.8rem;font-weight:600;color:var(--color-accent-hover)}.header-actions{display:flex;align-items:center;gap:8px;flex-shrink:0}.header-btn{width:38px;height:38px;border-radius:var(--radius-md);background:var(--color-bg-card);border:1px solid var(--color-border);display:grid;place-items:center;color:var(--color-text-secondary);font-size:1rem;transition:all var(--transition-base)}.header-btn:hover{background:var(--color-bg-hover);color:var(--color-text-primary);border-color:var(--color-border-active);transform:translateY(-1px)}.avatar{width:38px;height:38px;border-radius:var(--radius-full);background:linear-gradient(135deg,var(--color-accent),#c084fc);display:grid;place-items:center;font-size:.85rem;font-weight:700;color:#fff;border:2px solid var(--color-border-active);cursor:pointer;transition:all var(--transition-base);flex-shrink:0}.avatar:hover{box-shadow:var(--shadow-accent);transform:scale(1.05)}.sidebar{width:var(--sidebar-width);flex-shrink:0;background:var(--color-bg-secondary);border-right:1px solid var(--color-border);overflow-y:auto;height:100%}.sidebar-header{padding:20px 20px 16px;border-bottom:1px solid var(--color-border);position:sticky;top:0;background:var(--color-bg-secondary);z-index:10}.sidebar-header h3{font-size:.9rem;font-weight:600;margin-bottom:10px}.overall-progress{display:flex;justify-content:space-between;align-items:center;margin-bottom:6px}.overall-progress span{font-size:.75rem;color:var(--color-text-secondary)}.overall-progress strong{color:var(--color-success);font-size:.8rem}.module{border-bottom:1px solid var(--color-border)}.module-header{display:flex;align-items:center;gap:8px;padding:14px 20px;cursor:pointer;transition:background var(--transition-fast);-webkit-user-select:none;user-select:none}.module-header:hover{background:var(--color-bg-hover)}.module-chevron{font-size:.6rem;color:var(--color-text-muted);transition:transform var(--transition-base);margin-left:auto}.module-chevron.open{transform:rotate(180deg)}.module-icon{width:24px;height:24px;border-radius:var(--radius-sm);background:var(--color-accent-muted);display:grid;place-items:center;font-size:.65rem;flex-shrink:0}.module-info{flex:1;min-width:0}.module-title{font-size:.82rem;font-weight:600;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.module-meta{font-size:.7rem;color:var(--color-text-muted);margin-top:1px}.module-lessons{overflow:hidden;transition:max-height var(--transition-slow)}.lesson-item{display:flex;align-items:center;gap:10px;padding:9px 20px 9px 30px;cursor:pointer;transition:background var(--transition-fast);border-left:2px solid transparent}.lesson-item:hover{background:var(--color-bg-hover)}.lesson-item.active{background:var(--color-accent-muted);border-left-color:var(--color-accent)}.lesson-check{width:18px;height:18px;border-radius:var(--radius-full);border:2px solid var(--color-text-muted);display:grid;place-items:center;font-size:.55rem;flex-shrink:0;transition:all var(--transition-base)}.lesson-check.done{background:var(--color-success);border-color:var(--color-success);color:#fff}.lesson-check.active-check{border-color:var(--color-accent);background:var(--color-accent-muted)}.lesson-text{flex:1;min-width:0}.lesson-title{font-size:.78rem;font-weight:500;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.lesson-item.active .lesson-title{color:var(--color-text-primary)}.lesson-duration{font-size:.68rem;color:var(--color-text-muted);flex-shrink:0}.lesson-type-icon{font-size:.7rem;flex-shrink:0;width:16px;color:var(--color-text-muted)}.lesson-item.active .lesson-type-icon{color:var(--color-accent)}.player-area{flex:1;overflow-y:auto;display:flex;flex-direction:column}.video-wrapper{width:100%;background:#000;position:relative;overflow:hidden;aspect-ratio:16 / 9;max-height:55vh;flex-shrink:0}.video-placeholder{width:100%;height:100%;display:flex;flex-direction:column;align-items:center;justify-content:center;background:radial-gradient(ellipse at 50% 30%,#7c5cfc33,#000 70%);gap:16px}.play-btn{width:72px;height:72px;border-radius:var(--radius-full);background:var(--color-accent);border:none;display:grid;place-items:center;font-size:1.5rem;color:#fff;cursor:pointer;transition:all var(--transition-base);box-shadow:var(--shadow-accent)}.play-btn:hover{transform:scale(1.1);background:var(--color-accent-hover);box-shadow:0 0 40px var(--color-accent-glow)}.video-title-overlay{color:var(--color-text-primary);font-size:1rem;font-weight:500}.video-controls{position:absolute;bottom:0;left:0;right:0;padding:16px 20px 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var(--transition-base);display:flex;align-items:center;gap:6px}.tab-btn:hover{color:var(--color-text-primary)}.tab-btn.active{color:var(--color-accent-hover);border-bottom-color:var(--color-accent)}.tab-icon{font-size:.9rem}.tab-content{flex:1;padding-top:20px;animation:fadeIn .3s ease}@keyframes fadeIn{0%{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}.overview-grid{display:grid;grid-template-columns:1fr 260px;gap:24px}.overview-section h2{font-size:1.2rem;margin-bottom:8px}.overview-section p{font-size:.88rem;line-height:1.75;margin-bottom:16px}.instructor-card{display:flex;align-items:center;gap:12px;padding:16px;background:var(--color-bg-card);border-radius:var(--radius-lg);border:1px solid var(--color-border);margin-top:20px}.instructor-avatar{width:52px;height:52px;border-radius:var(--radius-full);background:linear-gradient(135deg,#f59e0b,#ef4444);display:grid;place-items:center;font-size:1.2rem;font-weight:700;color:#fff;flex-shrink:0}.instructor-info h4{font-size:.9rem;margin-bottom:3px}.instructor-info p{font-size:.78rem}.stats-panel{display:flex;flex-direction:column;gap:12px}.stat-card{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:14px 16px;display:flex;align-items:center;gap:12px;transition:all var(--transition-base)}.stat-card:hover{border-color:var(--color-border-active);transform:translate(3px)}.stat-icon{width:38px;height:38px;border-radius:var(--radius-md);display:grid;place-items:center;font-size:1rem;flex-shrink:0}.stat-icon.purple{background:var(--color-accent-muted)}.stat-icon.green{background:#22d3a526}.stat-icon.yellow{background:#f59e0b26}.stat-icon.blue{background:#38bdf826}.stat-value{font-size:1rem;font-weight:700}.stat-label{font-size:.72rem;color:var(--color-text-muted)}.tags{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}.tag{font-size:.72rem;padding:4px 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6px 20px var(--color-accent-glow)}.btn-secondary{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-md);padding:10px 16px;color:var(--color-text-secondary);font-size:.83rem;font-weight:500;transition:all var(--transition-base)}.btn-secondary:hover{background:var(--color-bg-hover);color:var(--color-text-primary);border-color:var(--color-border-active)}.question-list{display:flex;flex-direction:column;gap:14px}.question-card{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:16px;transition:all var(--transition-base)}.question-card:hover{border-color:var(--color-border-active);box-shadow:var(--shadow-sm);transform:translateY(-1px)}.question-header{display:flex;align-items:flex-start;gap:10px;margin-bottom:10px}.q-avatar{width:34px;height:34px;border-radius:var(--radius-full);display:grid;place-items:center;font-size:.75rem;font-weight:700;color:#fff;flex-shrink:0}.q-meta{flex:1}.q-name{font-size:.82rem;font-weight:600}.q-time{font-size:.72rem;color:var(--color-text-muted);margin-top:2px}.q-badge{font-size:.65rem;padding:3px 8px;border-radius:var(--radius-full);font-weight:600;flex-shrink:0}.q-badge.answered{background:#22d3a526;color:var(--color-success)}.q-badge.pending{background:#f59e0b26;color:var(--color-warning)}.question-text{font-size:.85rem;line-height:1.65;margin-bottom:12px}.question-actions{display:flex;gap:8px;flex-wrap:wrap}.action-btn{display:flex;align-items:center;gap:5px;font-size:.75rem;color:var(--color-text-muted);background:none;border:1px solid var(--color-border);border-radius:var(--radius-full);padding:4px 10px;transition:all var(--transition-base)}.action-btn:hover{color:var(--color-accent-hover);border-color:var(--color-accent);background:var(--color-accent-muted)}.answers-section{margin-top:14px;padding-top:14px;border-top:1px solid var(--color-border)}.answer-item{display:flex;gap:10px;padding:10px 0}.answer-item p{font-size:.82rem;line-height:1.6;margin-top:4px}.instructor-tag{font-size:.65rem;background:var(--color-accent-muted);color:var(--color-accent-hover);padding:2px 7px;border-radius:var(--radius-full);font-weight:600;margin-left:6px;vertical-align:middle}.downloads-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px;flex-wrap:wrap;gap:12px}.downloads-header h3{font-size:1rem}.downloads-header p{font-size:.8rem}.download-list{display:flex;flex-direction:column;gap:10px}.download-item{display:flex;align-items:center;gap:14px;padding:14px 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var(--color-border-active);color:var(--color-accent-hover);display:grid;place-items:center;font-size:.9rem;flex-shrink:0;transition:all var(--transition-base)}.download-btn:hover{background:var(--color-accent);color:#fff;transform:scale(1.1)}.tasks-grid{display:flex;flex-direction:column;gap:16px}.task-card{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:18px;transition:all var(--transition-base)}.task-card:hover{border-color:var(--color-border-active);box-shadow:var(--shadow-sm)}.task-card-header{display:flex;align-items:flex-start;gap:12px;margin-bottom:12px}.task-type-icon{width:40px;height:40px;border-radius:var(--radius-md);display:grid;place-items:center;font-size:1.1rem;flex-shrink:0}.task-type-icon.quiz{background:#7c5cfc26}.task-type-icon.project{background:#22d3a526}.task-type-icon.exercise{background:#f59e0b26}.task-info{flex:1}.task-title{font-size:.95rem;font-weight:700;margin-bottom:4px}.task-desc{font-size:.82rem;line-height:1.6}.task-footer{display:flex;align-items:center;justify-content:space-between;margin-top:14px;padding-top:12px;border-top:1px solid var(--color-border);gap:12px;flex-wrap:wrap}.task-meta-list{display:flex;gap:14px}.task-meta-item{font-size:.75rem;color:var(--color-text-muted);display:flex;align-items:center;gap:4px}.task-status-badge{font-size:.72rem;padding:4px 12px;border-radius:var(--radius-full);font-weight:600}.task-status-badge.completed{background:#22d3a526;color:var(--color-success)}.task-status-badge.in-progress{background:#7c5cfc26;color:var(--color-accent-hover)}.task-status-badge.pending{background:#f59e0b1a;color:var(--color-warning)}.btn-start{background:linear-gradient(135deg,var(--color-accent),var(--color-accent-hover));border:none;border-radius:var(--radius-md);padding:7px 16px;color:#fff;font-size:.8rem;font-weight:600;display:flex;align-items:center;gap:6px;transition:all var(--transition-base)}.btn-start:hover{transform:translateY(-1px);box-shadow:var(--shadow-accent)}.btn-review{background:var(--color-bg-hover);border:1px solid var(--color-border);border-radius:var(--radius-md);padding:7px 16px;color:var(--color-text-secondary);font-size:.8rem;font-weight:600;transition:all var(--transition-base)}.btn-review:hover{color:var(--color-text-primary);border-color:var(--color-border-active)}.modal-overlay{position:fixed;inset:0;background:#000000b3;-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);display:grid;place-items:center;z-index:200;animation:fadeIn .2s ease}.modal{background:var(--color-bg-card);border:1px solid var(--color-border-active);border-radius:var(--radius-xl);padding:28px;width:90%;max-width:520px;box-shadow:var(--shadow-lg);animation:slideUp .3s ease}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}.modal h3{font-size:1.1rem;margin-bottom:4px}.modal>p{font-size:.82rem;margin-bottom:20px}.form-group{margin-bottom:16px}.form-label{font-size:.8rem;font-weight:600;color:var(--color-text-secondary);display:block;margin-bottom:6px}.form-input,.form-textarea{width:100%;background:var(--color-bg-secondary);border:1px solid var(--color-border);border-radius:var(--radius-md);padding:11px 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.auth-left{background:linear-gradient(160deg,#eaecf4,#ddd0ff 60%,#eaecf4)}.auth-left:before{content:"";position:absolute;width:400px;height:400px;border-radius:50%;background:radial-gradient(circle,rgba(124,92,252,.25) 0%,transparent 70%);top:-80px;right:-80px;pointer-events:none}.auth-hero-text h1{font-size:2.6rem;font-weight:800;line-height:1.15;margin-bottom:14px}.gradient-text{background:linear-gradient(135deg,var(--color-accent-hover),var(--color-success));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}.auth-hero-text p{font-size:1rem;line-height:1.7;color:var(--color-text-secondary)}.auth-stats-row{display:flex;align-items:center;gap:20px}.auth-stat{text-align:center}.auth-stat strong{display:block;font-size:1.3rem;font-weight:800;color:var(--color-text-primary)}.auth-stat span{font-size:.75rem;color:var(--color-text-muted)}.auth-stat-divider{width:1px;height:36px;background:var(--color-border)}.auth-testimonial{background:var(--color-bg-glass);-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:18px 20px}.auth-testimonial p{font-size:.88rem;font-style:italic;line-height:1.65;margin-bottom:12px}.testimonial-author{display:flex;align-items:center;gap:10px;font-size:.82rem;color:var(--color-text-secondary)}.testimonial-author strong{color:var(--color-text-primary)}.auth-theme-btn{position:absolute;bottom:28px;left:52px;background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-full);width:40px;height:40px;display:grid;place-items:center;font-size:1rem;transition:all var(--transition-base)}.auth-theme-btn:hover{background:var(--color-bg-hover);transform:scale(1.08)}.auth-right{flex:1;display:flex;align-items:center;justify-content:center;padding:40px 24px;background:var(--color-bg-secondary)}.auth-card{width:100%;max-width:420px;background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-xl);padding:32px;box-shadow:var(--shadow-lg)}.auth-tabs{display:flex;background:var(--color-bg-secondary);border-radius:var(--radius-md);padding:4px;margin-bottom:24px}.auth-tab{flex:1;padding:9px;border:none;background:none;border-radius:calc(var(--radius-md) - 2px);font-size:.85rem;font-weight:600;color:var(--color-text-muted);transition:all var(--transition-base)}.auth-tab.active{background:var(--color-bg-card);color:var(--color-text-primary);box-shadow:var(--shadow-sm)}.auth-social-row{display:flex;gap:10px;margin-bottom:20px}.social-btn{flex:1;background:var(--color-bg-secondary);border:1px solid var(--color-border);border-radius:var(--radius-md);padding:10px;font-size:.83rem;font-weight:600;color:var(--color-text-primary);display:flex;align-items:center;justify-content:center;gap:7px;transition:all var(--transition-base)}.social-btn:hover{background:var(--color-bg-hover);border-color:var(--color-border-active);transform:translateY(-1px)}.auth-divider{text-align:center;position:relative;margin:20px 0;color:var(--color-text-muted);font-size:.75rem}.auth-divider:before,.auth-divider:after{content:"";position:absolute;top:50%;width:calc(50% - 70px);height:1px;background:var(--color-border)}.auth-divider:before{left:0}.auth-divider:after{right:0}.password-field{position:relative}.password-field .form-input{padding-right:42px}.show-pass-btn{position:absolute;right:10px;top:50%;transform:translateY(-50%);background:none;border:none;font-size:1rem;line-height:1;color:var(--color-text-muted);cursor:pointer;transition:color var(--transition-fast)}.show-pass-btn:hover{color:var(--color-text-primary)}.forgot-link{font-size:.78rem;color:var(--color-accent-hover);text-decoration:none}.forgot-link:hover{text-decoration:underline}.checkbox-label{display:flex;align-items:flex-start;gap:8px;font-size:.78rem;color:var(--color-text-secondary);margin-bottom:16px;cursor:pointer;line-height:1.5}.btn-auth-submit{width:100%;background:linear-gradient(135deg,var(--color-accent),var(--color-accent-hover));border:none;border-radius:var(--radius-md);padding:13px;color:#fff;font-size:.95rem;font-weight:700;transition:all var(--transition-base);box-shadow:0 4px 15px var(--color-accent-glow);margin-top:4px}.btn-auth-submit:hover{transform:translateY(-2px);box-shadow:0 8px 25px var(--color-accent-glow)}.auth-footer-note{text-align:center;font-size:.82rem;margin-top:18px}.auth-instructor-link{text-align:center;font-size:.78rem;margin-top:10px;color:var(--color-text-muted)}.link-btn{background:none;border:none;color:var(--color-accent-hover);font-size:inherit;font-weight:600;cursor:pointer;padding:0}.link-btn:hover{text-decoration:underline}@media(max-width:860px){.auth-left{display:none}.auth-page{justify-content:center}}.instructor-page{min-height:100vh;background:var(--color-bg-primary);display:flex;flex-direction:column}.instructor-header{height:var(--header-height);background:var(--color-bg-glass);-webkit-backdrop-filter:blur(20px);backdrop-filter:blur(20px);border-bottom:1px solid var(--color-border);display:flex;align-items:center;padding:0 24px;gap:16px;position:sticky;top:0;z-index:100}.back-btn{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-md);padding:8px 14px;font-size:.82rem;font-weight:600;color:var(--color-text-secondary);transition:all var(--transition-base);flex-shrink:0}.back-btn:hover{color:var(--color-text-primary);border-color:var(--color-border-active);background:var(--color-bg-hover)}.instructor-badge{font-size:.72rem;font-weight:600;background:var(--color-accent-muted);color:var(--color-accent-hover);border:1px solid var(--color-border-active);border-radius:var(--radius-full);padding:3px 10px;margin-left:4px}.instructor-body{flex:1;padding:32px;max-width:1200px;margin:0 auto;width:100%;position:relative}.publish-toast{position:fixed;top:80px;left:50%;transform:translate(-50%);background:linear-gradient(135deg,var(--color-success),#0ea57e);color:#fff;font-size:.9rem;font-weight:600;padding:14px 24px;border-radius:var(--radius-full);box-shadow:0 8px 30px #22d3a566;z-index:200;animation:slideUp .3s ease}.instructor-grid{display:grid;grid-template-columns:1fr 300px;gap:28px;align-items:start}.instructor-form{display:flex;flex-direction:column;gap:24px}.form-section{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:22px 24px}.section-title{font-size:.95rem;font-weight:700;margin-bottom:18px}.form-row{display:flex;gap:16px}.form-select{appearance:none;cursor:pointer}.toggle-row{display:flex;align-items:center;gap:10px;cursor:pointer;padding-top:6px}.toggle-row input[type=checkbox]{display:none}.toggle-slider{width:42px;height:24px;border-radius:var(--radius-full);background:var(--color-bg-hover);border:1px solid var(--color-border);position:relative;flex-shrink:0;transition:background var(--transition-base)}.toggle-slider:after{content:"";position:absolute;width:18px;height:18px;border-radius:50%;background:var(--color-text-muted);top:2px;left:2px;transition:all var(--transition-base)}.toggle-row input:checked+.toggle-slider{background:var(--color-accent);border-color:var(--color-accent)}.toggle-row input:checked+.toggle-slider:after{left:20px;background:#fff}.toggle-label{font-size:.83rem;font-weight:500}.tag-input-container{display:flex;flex-wrap:wrap;gap:6px;align-items:center;padding:8px 10px;background:var(--color-bg-secondary);border:1px solid var(--color-border);border-radius:var(--radius-md);min-height:44px;cursor:text}.tag-remove{background:none;border:none;color:var(--color-accent-hover);font-size:.9rem;line-height:1;cursor:pointer;padding:0 2px}.tag-text-input{flex:1;min-width:100px;background:none;border:none;outline:none;color:var(--color-text-primary);font-size:.83rem;font-family:inherit}.drop-zone{border:2px dashed var(--color-border);border-radius:var(--radius-lg);padding:40px 24px;text-align:center;cursor:pointer;transition:all var(--transition-base);display:flex;flex-direction:column;align-items:center;gap:8px}.drop-zone:hover,.drop-zone.drag-over{border-color:var(--color-accent);background:var(--color-accent-muted)}.drop-zone.has-file{border-style:solid;border-color:var(--color-success);background:#22d3a50f;flex-direction:row;justify-content:flex-start;gap:16px;padding:20px 24px;text-align:left}.drop-icon{font-size:2.4rem}.drop-title{font-size:.9rem;font-weight:500}.drop-link{color:var(--color-accent-hover);font-weight:600}.drop-sub{font-size:.75rem;color:var(--color-text-muted)}.file-selected{display:flex;align-items:center;gap:14px;width:100%}.file-icon{font-size:1.8rem;flex-shrink:0}.remove-file-btn{margin-left:auto;background:none;border:1px solid var(--color-danger);color:var(--color-danger);border-radius:var(--radius-md);padding:5px 12px;font-size:.75rem;font-weight:600;flex-shrink:0;transition:all var(--transition-fast)}.remove-file-btn:hover{background:#ef44441f}.thumb-upload-row{display:flex;gap:20px;align-items:flex-start}.thumb-drop{width:200px;height:120px;flex-shrink:0;border:2px dashed var(--color-border);border-radius:var(--radius-md);cursor:pointer;overflow:hidden;transition:border-color var(--transition-base)}.thumb-drop:hover{border-color:var(--color-accent)}.thumb-placeholder{width:100%;height:100%;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:4px;color:var(--color-text-muted);font-size:.75rem;text-align:center}.thumb-hints p{font-size:.83rem;color:var(--color-text-secondary);margin-bottom:10px}.thumb-hints ul{padding-left:16px}.thumb-hints li{font-size:.78rem;color:var(--color-text-muted);margin-bottom:4px}.attach-label{display:inline-block;margin-bottom:12px}.attachment-list{display:flex;flex-direction:column;gap:6px;margin-top:10px}.attachment-item{display:flex;align-items:center;gap:10px;padding:8px 12px;background:var(--color-bg-secondary);border-radius:var(--radius-md);font-size:.82rem}.attach-size{margin-left:auto;font-size:.72rem;color:var(--color-text-muted)}.instructor-actions{display:flex;gap:12px;justify-content:flex-end}.instructor-sidebar{display:flex;flex-direction:column;gap:20px;position:sticky;top:calc(var(--header-height) + 32px)}.preview-card{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:20px}.lesson-preview-thumb{width:100%;aspect-ratio:16/9;background:var(--color-bg-secondary);border-radius:var(--radius-md);overflow:hidden;position:relative}.preview-badge{position:absolute;top:8px;right:8px;font-size:.68rem;font-weight:700;padding:3px 8px;border-radius:var(--radius-full);background:#000000a6;color:#fff;-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px)}.instructor-tips{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:18px 20px}.instructor-tips h4{font-size:.88rem;margin-bottom:14px}.tip-item{display:flex;align-items:center;gap:10px;font-size:.8rem;color:var(--color-text-secondary);padding:5px 0}.tip-ok{color:var(--color-success);font-weight:700}.tip-pending{color:var(--color-text-muted)}@media(max-width:900px){.instructor-grid{grid-template-columns:1fr}.instructor-sidebar{position:static;flex-direction:row;flex-wrap:wrap}.preview-card,.instructor-tips{flex:1 1 280px}}.instructor-shell{display:flex;flex:1;overflow:hidden;height:calc(100vh - var(--header-height))}.instructor-nav{width:220px;flex-shrink:0;background:var(--color-bg-secondary);border-right:1px solid var(--color-border);padding:16px 10px;display:flex;flex-direction:column;gap:4px;overflow-y:auto}.instructor-nav-item{display:flex;align-items:center;gap:10px;padding:10px 14px;border-radius:var(--radius-md);border:none;background:none;color:var(--color-text-secondary);font-size:.85rem;font-weight:500;cursor:pointer;transition:all var(--transition-base);text-align:left;position:relative;width:100%}.instructor-nav-item:hover{background:var(--color-bg-hover);color:var(--color-text-primary)}.instructor-nav-item.active{background:var(--color-accent-muted);color:var(--color-accent-hover);font-weight:600}.nav-icon{font-size:1.1rem;flex-shrink:0}.nav-label{flex:1}.nav-badge{background:var(--color-warning);color:#000;font-size:.65rem;font-weight:800;padding:2px 6px;border-radius:var(--radius-full);flex-shrink:0}.instructor-main{flex:1;overflow-y:auto;padding:28px 32px}.dash-section-header{display:flex;align-items:flex-start;justify-content:space-between;gap:16px;margin-bottom:24px;flex-wrap:wrap}.dash-section-title{font-size:1.2rem;font-weight:700;margin-bottom:2px}.dash-section-sub{font-size:.82rem;color:var(--color-text-muted)}.dash-stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-bottom:28px}.dash-stat-card{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:16px 18px;display:flex;align-items:center;gap:14px;transition:all var(--transition-base)}.dash-stat-card:hover{border-color:var(--color-border-active);transform:translateY(-2px);box-shadow:var(--shadow-sm)}.dash-stat-value{font-size:1.5rem;font-weight:800;line-height:1;margin-bottom:3px}.dash-two-col{display:grid;grid-template-columns:1fr 1fr;gap:20px}.dash-panel{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:20px}.dash-panel-title{font-size:.9rem;font-weight:700;margin-bottom:14px}.dash-list-item{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:9px 0;border-bottom:1px solid var(--color-border)}.dash-list-item:last-child{border-bottom:none}.dash-list-name{font-size:.83rem;font-weight:600;margin-bottom:2px}.dash-list-sub{font-size:.72rem;color:var(--color-text-muted)}.dash-table-wrapper{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-lg);overflow:hidden}.dash-table{width:100%;border-collapse:collapse}.dash-table th{text-align:left;font-size:.72rem;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--color-text-muted);padding:12px 16px;background:var(--color-bg-secondary);border-bottom:1px solid var(--color-border)}.dash-table td{padding:12px 16px;font-size:.83rem;border-bottom:1px solid var(--color-border);vertical-align:middle}.dash-table tr:last-child td{border-bottom:none}.dash-table tr:hover td{background:var(--color-bg-hover)}.table-badge{display:inline-flex;align-items:center;gap:4px;font-size:.68rem;font-weight:600;padding:3px 9px;border-radius:var(--radius-full);white-space:nowrap}.badge-green{background:#22d3a526;color:var(--color-success)}.badge-yellow{background:#f59e0b26;color:var(--color-warning)}.badge-gray{background:var(--color-bg-hover);color:var(--color-text-muted)}.badge-purple{background:var(--color-accent-muted);color:var(--color-accent-hover)}.row-actions{display:flex;gap:4px;align-items:center}.icon-btn{width:30px;height:30px;border-radius:var(--radius-sm);border:1px solid var(--color-border);background:none;font-size:.85rem;display:grid;place-items:center;cursor:pointer;transition:all var(--transition-fast);color:var(--color-text-secondary)}.icon-btn:hover{background:var(--color-bg-hover);border-color:var(--color-border-active)}.icon-btn-danger:hover{background:#ef44441f;border-color:var(--color-danger);color:var(--color-danger)}.dash-inline-form{background:var(--color-bg-card);border:1px solid var(--color-border-active);border-radius:var(--radius-lg);padding:18px 20px;margin-bottom:20px}.activity-type-selector{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.type-card{border:2px solid var(--color-border);border-radius:var(--radius-lg);padding:18px 14px;text-align:center;cursor:pointer;display:flex;flex-direction:column;align-items:center;gap:6px;transition:all var(--transition-base)}.type-card:hover{border-color:var(--color-accent);background:var(--color-accent-muted)}.type-card.active{border-color:var(--color-accent);background:var(--color-accent-muted);box-shadow:0 0 0 3px var(--color-accent-glow)}.type-card strong{font-size:.9rem}.type-card span{font-size:.75rem;color:var(--color-text-muted)}.question-builder{background:var(--color-bg-secondary);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:18px 20px;margin-bottom:14px}.options-grid{display:flex;flex-direction:column;gap:8px}.option-row{display:flex;align-items:center;gap:10px;padding:8px 12px;border-radius:var(--radius-md);border:1px solid var(--color-border);background:var(--color-bg-card);cursor:pointer;transition:all var(--transition-fast)}.option-row:hover{border-color:var(--color-border-active)}.option-row.option-correct{border-color:var(--color-success);background:#22d3a514}.option-row input[type=radio]{accent-color:var(--color-success);flex-shrink:0}.option-input{flex:1;background:none;border:none;outline:none;color:var(--color-text-primary);font-size:.83rem;font-family:inherit}.correct-tag{font-size:.68rem;font-weight:700;color:var(--color-success);flex-shrink:0}.rubric-row{display:flex;align-items:center;gap:10px;margin-bottom:10px}.rubric-num{width:24px;height:24px;border-radius:50%;background:var(--color-accent-muted);color:var(--color-accent-hover);font-size:.72rem;font-weight:700;display:grid;place-items:center;flex-shrink:0}.filter-chip{background:var(--color-bg-card);border:1px solid var(--color-border);border-radius:var(--radius-full);padding:6px 16px;font-size:.8rem;font-weight:500;color:var(--color-text-secondary);cursor:pointer;transition:all var(--transition-base)}.filter-chip:hover{border-color:var(--color-border-active);color:var(--color-text-primary)}.filter-chip.active{background:var(--color-accent-muted);border-color:var(--color-accent);color:var(--color-accent-hover);font-weight:600}.submission-preview{background:var(--color-bg-secondary);border:1px solid var(--color-border);border-radius:var(--radius-md);padding:14px 16px;min-height:80px}@media(max-width:900px){.dash-stats-grid{grid-template-columns:repeat(2,1fr)}.dash-two-col,.activity-type-selector{grid-template-columns:1fr}}@media(max-width:680px){.instructor-nav{display:none}.instructor-main{padding:16px}}