:root{--bg-color: #0d1321;--surface-color: #1d2d44;--surface-hover: #3e5c76;--text-primary: #f0ebd8;--text-secondary: #748cab;--accent-color: #84a98c;--accent-hover: #52796f;--accent-text: #0d1321}body{margin:0;font-family:Inter,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Open Sans,Helvetica Neue,sans-serif;background-color:var(--bg-color);color:var(--text-primary);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}::-webkit-scrollbar{width:8px}::-webkit-scrollbar-track{background:var(--bg-color)}::-webkit-scrollbar-thumb{background:var(--surface-color);border-radius:4px}::-webkit-scrollbar-thumb:hover{background:var(--surface-hover)}.container{max-width:1400px;margin:0 auto;padding:20px;min-height:100vh;display:flex;flex-direction:column}header{padding:20px 0;margin-bottom:20px;border-bottom:1px solid var(--surface-color);display:flex;justify-content:space-between;align-items:center}h1{font-size:1.8rem;font-weight:700;margin:0;color:var(--accent-color)}.subtitle{font-size:1rem;color:var(--text-secondary)}main{display:grid;grid-template-columns:1fr 350px;gap:30px;flex:1}@media(max-width:900px){main{grid-template-columns:1fr}}.video-section{display:flex;flex-direction:column;gap:20px}.video-wrapper{position:relative;padding-bottom:56.25%;height:0;background:#000;border-radius:12px;overflow:hidden;box-shadow:0 10px 30px #00000080;border:1px solid var(--surface-color)}.video-wrapper iframe{position:absolute;top:0;left:0;width:100%;height:100%}.video-info h2{margin:0 0 10px;font-size:1.5rem}.video-meta{display:flex;gap:15px;color:var(--text-secondary);font-size:.9rem;align-items:center}.badge{background:var(--surface-color);padding:4px 12px;border-radius:20px;color:var(--accent-color);font-weight:500}.playlist-section{background:var(--surface-color);border-radius:12px;padding:20px;height:fit-content;max-height:calc(100vh - 100px);overflow-y:auto;border:1px solid rgba(255,255,255,.05)}.playlist-header{margin-bottom:20px;padding-bottom:10px;border-bottom:1px solid rgba(255,255,255,.1);font-weight:600;font-size:1.2rem}.module-group{margin-bottom:20px}.module-title{font-size:.85rem;text-transform:uppercase;letter-spacing:1px;color:var(--text-secondary);margin-bottom:10px;padding-left:10px}.video-item{display:flex;align-items:center;padding:12px;border-radius:8px;cursor:pointer;transition:all .2s ease;gap:10px;margin-bottom:5px}.video-item:hover{background:#ffffff0d}.video-item.active{background:var(--accent-color);color:var(--accent-text)}.video-item.active .play-icon{opacity:1}.video-item-info{flex:1}.video-item-title{font-size:.95rem;font-weight:500;line-height:1.3}.video-item-duration{font-size:.8rem;opacity:.7;margin-top:4px}.play-icon{width:20px;height:20px;opacity:.5}.nav-buttons{display:flex;justify-content:space-between;margin-top:20px}.btn{background:var(--surface-color);color:var(--text-primary);border:1px solid rgba(255,255,255,.1);padding:10px 20px;border-radius:8px;cursor:pointer;font-weight:500;display:flex;align-items:center;gap:8px;transition:all .2s}.btn:hover:not(:disabled){background:var(--surface-hover);border-color:var(--accent-color)}.btn:disabled{opacity:.5;cursor:not-allowed}.btn-primary{background:var(--accent-color);color:var(--accent-text)}.btn-primary:hover{background:var(--accent-hover)}