.vma-classroom{font-family:system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;background:#f4f6f8;color:#111;border-radius:18px;overflow:hidden;max-width:1500px;margin:20px auto;box-shadow:0 10px 40px rgba(0,0,0,.08)}.vma-class-header{display:flex;justify-content:space-between;align-items:center;padding:18px 22px;background:#111;color:#fff}.vma-class-header h1{margin:7px 0 2px;font-size:25px}.vma-class-header p{margin:0;opacity:.7}.vma-live-pill{background:#e21d2d;padding:6px 10px;border-radius:999px;font-size:12px;font-weight:700}.vma-layout{display:grid;grid-template-columns:230px 1fr;min-height:720px}.vma-side{background:#fff;padding:18px;border-right:1px solid #ddd}.vma-side h3{margin-top:0}.vma-student-list>div{padding:9px;border-bottom:1px solid #eee}.vma-main{padding:16px}.vma-tabs{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:12px}.vma-tabs button{border:1px solid #ddd;background:#fff;border-radius:9px;padding:10px 13px;cursor:pointer}.vma-tabs button.active{background:#111;color:#fff}.vma-tab{display:none}.vma-tab.active{display:block}.vma-video-box{aspect-ratio:16/9;background:#000;border-radius:13px;overflow:hidden}.vma-video-box iframe{width:100%;height:100%;border:0}.vma-board-wrap{background:#fff;border-radius:13px;overflow:hidden;min-height:430px}.vma-board{display:block;width:100%;height:520px;touch-action:none;cursor:crosshair}.vma-slide-area{background:#fff;min-height:520px;border-radius:13px;display:flex;align-items:center;justify-content:center;overflow:hidden}.vma-slide-image{max-width:100%;max-height:520px;object-fit:contain}.vma-slide-placeholder{opacity:.55}.vma-tools{display:flex;gap:7px;flex-wrap:wrap;padding:12px;background:#fff;border-radius:12px;margin-top:12px}.vma-tools button{border:1px solid #ddd;background:#f7f7f7;padding:8px 11px;border-radius:8px}.vma-slide-url{min-width:250px;padding:8px}.vma-chat-list{background:#fff;border-radius:12px;min-height:350px;padding:15px;overflow:auto}.vma-chat-list>div{padding:8px;border-bottom:1px solid #eee}.vma-chat-teacher,.vma-chat-student{display:flex;gap:8px;margin-top:10px}.vma-chat-teacher input,.vma-chat-student input{flex:1;padding:11px}.vma-chat-teacher button,.vma-chat-student button,.vma-attend{padding:10px 14px;border:0;border-radius:8px;background:#111;color:#fff}.vma-class-actions{margin-top:12px}.vma-materials{margin-top:20px;background:#fff;padding:15px;border-radius:12px}.vma-materials a{display:block;padding:7px}.vma-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:18px}.vma-card{background:#fff;padding:20px;border-radius:14px;box-shadow:0 5px 20px rgba(0,0,0,.07)}.vma-card>a{display:inline-block;margin-top:10px;background:#111;color:#fff;padding:9px 13px;border-radius:8px;text-decoration:none}.vma-recording{display:grid;grid-template-columns:280px 1fr;gap:18px;background:#fff;padding:15px;border-radius:13px;margin:15px 0}.vma-thumb{aspect-ratio:16/9}.vma-thumb iframe{width:100%;height:100%;border:0}.vma-faculty-panel table{width:100%;border-collapse:collapse}.vma-faculty-panel td,.vma-faculty-panel th{padding:10px;border-bottom:1px solid #ddd;text-align:left}.vma-login-required{padding:20px;background:#fff;border-radius:10px}@media(max-width:800px){.vma-layout{grid-template-columns:1fr}.vma-side{border-right:0;border-bottom:1px solid #ddd}.vma-recording{grid-template-columns:1fr}.vma-board{height:400px}.vma-class-header{align-items:flex-start}.vma-main{padding:10px}}