:root{--color-primary: #D4AF37;--color-primary-hover: #C5A028;--color-primary-light: #F4E5B0;--color-background: #0f0f13;--color-surface: #1a1a20;--color-surface-hover: #25252e;--color-text-main: #FFFFFF;--color-text-secondary: #A0A0A5;--color-text-muted: #606065;--color-success: #22c55e;--color-error: #ef4444;--space-xs: 4px;--space-sm: 8px;--space-md: 16px;--space-lg: 24px;--space-xl: 32px;--space-2xl: 48px;--font-family: "Inter", system-ui, -apple-system, sans-serif;--font-size-sm: .875rem;--font-size-base: 1rem;--font-size-lg: 1.125rem;--font-size-xl: 1.25rem;--font-size-2xl: 1.5rem;--font-size-3xl: 2rem;--radius-sm: 6px;--radius-md: 12px;--radius-lg: 16px;--radius-full: 9999px;--transition-fast: .15s ease;--transition-normal: .3s ease;--shadow-sm: 0 1px 2px 0 rgb(0 0 0 / .05);--shadow-md: 0 4px 6px -1px rgb(0 0 0 / .3), 0 2px 4px -2px rgb(0 0 0 / .3);--shadow-glow: 0 0 15px rgba(212, 175, 55, .15)}*{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-family);background-color:var(--color-background);color:var(--color-text-main);line-height:1.5;-webkit-font-smoothing:antialiased}button{cursor:pointer;border:none;background:none;font-family:inherit}a{color:inherit;text-decoration:none}h1,h2,h3,h4,h5,h6{font-weight:600;letter-spacing:-.02em}.container{width:100%;max-width:1200px;margin:0 auto;padding:0 var(--space-md)}.btn{display:inline-flex;align-items:center;justify-content:center;padding:.75rem 1.5rem;border-radius:var(--radius-md);font-weight:500;transition:all var(--transition-fast);gap:.5rem}.btn-primary{background:var(--color-primary);color:#000}.btn-primary:hover{background:var(--color-primary-hover);transform:translateY(-1px);box-shadow:var(--shadow-glow)}.btn-outline{border:1px solid var(--color-surface-hover);color:var(--color-text-main)}.btn-outline:hover{background:var(--color-surface-hover)}.btn-ghost{color:var(--color-text-secondary)}.btn-ghost:hover{color:var(--color-text-main);background:#ffffff0d}.animate-fade-in{animation:fadeIn var(--transition-normal) forwards}@keyframes fadeIn{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}::-webkit-scrollbar{width:8px}::-webkit-scrollbar-track{background:var(--color-background)}::-webkit-scrollbar-thumb{background:var(--color-surface-hover);border-radius:4px}::-webkit-scrollbar-thumb:hover{background:var(--color-text-muted)}.animate-spin{animation:spin 1s linear infinite}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}.animate-slide-up{opacity:0;animation:slideUp .5s cubic-bezier(.16,1,.3,1) forwards}.delay-100{animation-delay:.1s}.delay-200{animation-delay:.2s}.delay-300{animation-delay:.3s}.hover-scale{transition:transform var(--transition-normal),box-shadow var(--transition-normal)}.hover-scale:hover{transform:translateY(-4px) scale(1.02);box-shadow:var(--shadow-glow)}.btn:active{transform:scale(.96)}.layout{display:flex;height:100vh;width:100%;overflow:hidden;background-color:var(--color-background)}.sidebar{width:260px;background-color:var(--color-surface);border-right:1px solid var(--color-surface-hover);display:flex;flex-direction:column;transition:transform var(--transition-normal);z-index:50}.sidebar-header{padding:var(--space-lg);display:flex;align-items:center;justify-content:space-between}.logo{font-size:var(--font-size-xl);font-weight:700;letter-spacing:1px}.logo .highlight{color:var(--color-primary)}.close-menu-btn{display:none;font-size:2rem;color:var(--color-text-secondary)}.user-info{padding:0 var(--space-lg) var(--space-lg);display:flex;align-items:center;gap:var(--space-sm);border-bottom:1px solid var(--color-surface-hover);margin-bottom:var(--space-md)}.avatar{width:40px;height:40px;border-radius:var(--radius-full);background:var(--color-surface-hover);color:var(--color-primary);display:flex;align-items:center;justify-content:center;font-weight:700;font-size:var(--font-size-lg)}.details{display:flex;flex-direction:column}.details .name{font-weight:600;font-size:var(--font-size-sm)}.details .role{font-size:.75rem;color:var(--color-text-secondary)}.nav-menu{flex:1;padding:0 var(--space-md);display:flex;flex-direction:column;gap:var(--space-xs)}.nav-item{display:flex;align-items:center;gap:var(--space-md);padding:var(--space-md);border-radius:var(--radius-md);color:var(--color-text-secondary);font-weight:500;transition:all var(--transition-fast)}.nav-item:hover{background-color:var(--color-surface-hover);color:var(--color-text-main)}.nav-item.active{background:#d4af371a;color:var(--color-primary);border-right:3px solid var(--color-primary)}.sidebar-footer{padding:var(--space-md);border-top:1px solid var(--color-surface-hover)}.logout-btn{width:100%;color:var(--color-error)}.logout-btn:hover{background:#ef44441a;color:var(--color-error)}.main-content{flex:1;display:flex;flex-direction:column;overflow:hidden;position:relative}.top-bar{height:70px;display:flex;align-items:center;padding:0 var(--space-lg);border-bottom:1px solid var(--color-surface-hover)}.menu-btn{display:none;color:var(--color-text-main);margin-right:var(--space-md)}.content-area{flex:1;padding:var(--space-lg);overflow-y:auto}.overlay{display:none}@media(max-width:768px){.sidebar{position:fixed;height:100%;transform:translate(-100%)}.sidebar.open{transform:translate(0)}.menu-btn,.close-menu-btn{display:block}.overlay{display:block;position:fixed;inset:0;background:#00000080;z-index:40;-webkit-backdrop-filter:blur(2px);backdrop-filter:blur(2px)}}.course-player-container{display:flex;height:100vh;flex-direction:column;overflow:hidden}.player-header{height:60px;border-bottom:1px solid var(--color-surface-hover);display:flex;align-items:center;padding:0 var(--space-md);background:var(--color-surface);flex-shrink:0}.player-header h3{margin:0;font-size:1.1rem;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.player-body{display:flex;flex:1;overflow:hidden;position:relative}.video-section{flex:1;background:#000;display:flex;flex-direction:column;overflow-y:auto;position:relative}.quiz-active{background:var(--color-background)}.video-container{flex:1;position:relative;width:100%;min-height:300px;background:#000;display:flex;align-items:center;justify-content:center}.pdf-viewer{width:100%;flex:1;border:none;height:100%}.video-element{width:100%;height:100%;max-height:80vh;object-fit:contain;outline:none}.lesson-info{padding:var(--space-lg);background:var(--color-background)}.sidebar-section{width:350px;border-left:1px solid var(--color-surface-hover);background:var(--color-surface);overflow-y:auto;display:flex;flex-direction:column;flex-shrink:0}.sidebar-header-title{padding:var(--space-md);border-bottom:1px solid var(--color-surface-hover);color:var(--color-text-secondary);font-size:.9rem;text-transform:uppercase;font-weight:600}.module-header{padding:var(--space-md);background:var(--color-surface-hover);font-size:.9rem;font-weight:600;position:sticky;top:0;z-index:10}.lesson-item{padding:12px var(--space-md);cursor:pointer;display:flex;align-items:center;gap:10px;transition:background .2s;border-left:3px solid transparent}.lesson-item:hover{background:#ffffff0d}.lesson-item.active{background:#d4af371a;border-left-color:var(--color-primary)}.lesson-item.completed .icon-check{color:var(--color-success)}@media(max-width:900px){.player-body{flex-direction:column;overflow-y:auto}.video-section{flex:none;width:100%;height:auto}.video-container{height:56.25vw;min-height:auto}.sidebar-section{width:100%;height:auto;max-height:50vh;border-left:none;border-top:1px solid var(--color-surface-hover);flex:1}}