body{margin:0;font-family:Arial,Helvetica,sans-serif;background:#000;color:#f5f5f5}
.container{max-width:1200px;margin:auto;padding:1.5rem}
.udemy-header{border-bottom:1px solid #333;background:#000}
.subtitle{color:#DAA520}
.layout{display:grid;gap:2rem}
@media(min-width:900px){.layout{grid-template-columns:2.2fr 1fr}}
.video-wrapper{background:#111;border-radius:1rem;margin-bottom:1rem}
.video-placeholder{height:360px;display:flex;align-items:center;justify-content:center;font-size:1.2rem;color:#DAA520}
.tabs{display:flex;gap:.5rem;border-bottom:1px solid #333;margin-bottom:1rem}
.tab{background:none;border:none;color:#c0c0c0;padding:.6rem 1rem;cursor:pointer}
.tab.active{color:#DAA520;border-bottom:2px solid #DAA520}
.tab-panel{display:none}
.tab-panel.active{display:block}
.sidebar{border:1px solid #333;border-radius:1rem;padding:1rem;background:#0b0b0b}
details{border-bottom:1px solid #333;padding:.5rem 0}
summary{cursor:pointer;font-weight:700}