:root{--brand:#e8761a;--brand-dark:#c9620f;--brand-light:#fdeccf;--pill:#fbe5a8;--ink:#1b1b1f;--ink-soft:#5f6368;--border:#e9e6e1;--bg:#f8f7f5;--surface:#fff;--good:#16a34a;--good-bg:#e9f9ee;--radius:12px;--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light}*{box-sizing:border-box}html,body,#root{height:100%}body{background:var(--bg);color:var(--ink);-webkit-font-smoothing:antialiased;margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif}a{color:var(--brand)}button{font-family:inherit}.btn{cursor:pointer;background:var(--brand);color:#fff;border:none;border-radius:8px;padding:10px 16px;font-size:14px;font-weight:600;transition:background .15s}.btn:hover{background:var(--brand-dark)}.btn.secondary{background:var(--surface);color:var(--ink);border:1px solid var(--border)}.btn.secondary:hover{background:var(--bg)}.btn:disabled{opacity:.5;cursor:not-allowed}input,textarea,select{border:1px solid var(--border);background:var(--surface);color:var(--ink);border-radius:8px;width:100%;padding:9px 12px;font-family:inherit;font-size:14px}input:focus,textarea:focus,select:focus{outline:2px solid var(--brand);outline-offset:-1px}input[type=radio],input[type=checkbox]{flex:none;width:auto}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:0 1px 2px #10121b0a}.progress-bar{background:var(--border);border-radius:999px;height:8px;overflow:hidden}.progress-bar>div{background:var(--good);height:100%;transition:width .3s}.topbar{background:var(--surface);border-bottom:1px solid var(--border);justify-content:space-between;align-items:center;padding:14px 24px;display:flex}.topbar .brand{color:var(--ink);align-items:center;gap:8px;font-size:18px;font-weight:800;text-decoration:none;display:flex}.callout{border-left:3px solid var(--brand);background:var(--brand-light);border-radius:0 8px 8px 0;margin:16px 0;padding:12px 16px}.cover{border-radius:var(--radius) var(--radius) 0 0;background:radial-gradient(circle at 70% 30%,#4a2d12 0%,#17120d 55%,#0d0b09 100%);justify-content:center;align-items:center;height:150px;font-size:64px;display:flex}.course-card{color:inherit;text-decoration:none;transition:box-shadow .15s,transform .15s;display:block;overflow:hidden}.course-card:hover{transform:translateY(-2px);box-shadow:0 6px 18px #10121b1a}.course-card .body{padding:16px 18px 18px}.classroom{grid-template-columns:290px minmax(0,1fr);align-items:start;gap:28px;max-width:1100px;margin:0 auto;padding:24px 16px 48px;display:grid}.classroom-side{max-height:calc(100vh - 32px);position:sticky;top:16px;overflow-y:auto}.cnav{margin-top:14px}.cnav-section{margin-bottom:6px}.cnav-head{width:100%;color:var(--ink);cursor:pointer;text-align:left;background:0 0;border:none;align-items:center;padding:10px 8px 6px;font-size:14px;font-weight:700;display:flex}.cnav-head-title{text-overflow:ellipsis;white-space:nowrap;flex:1;overflow:hidden}.cnav-chevron{color:var(--ink-soft);transition:transform .15s;transform:rotate(180deg)}.cnav-chevron.open{transform:rotate(0)}.cnav-lesson{width:100%;color:var(--ink);text-align:left;cursor:pointer;background:0 0;border:none;border-radius:10px;align-items:center;gap:10px;padding:10px 12px;font-size:14px;display:flex}.cnav-lesson:hover:not(:disabled){background:#efece7}.cnav-lesson.active{background:var(--pill)}.cnav-lesson:disabled{color:var(--ink-soft);cursor:default}.cnav-icon{flex:none}.cnav-title{text-overflow:ellipsis;white-space:nowrap;flex:1;min-width:0;overflow:hidden}.cnav-check{background:var(--good);color:#fff;border-radius:50%;flex:none;justify-content:center;align-items:center;width:20px;height:20px;font-size:12px;font-weight:700;display:flex}.cnav-lock{font-size:12px}.cnav-free{color:var(--brand-dark);background:var(--brand-light);border-radius:999px;padding:2px 8px;font-size:10px;font-weight:800}.lesson-nav{border-top:1px solid var(--border);justify-content:space-between;gap:12px;margin-top:28px;padding-top:20px;display:flex}.check-btn{border:2px solid var(--border);background:var(--surface);width:36px;height:36px;color:var(--border);cursor:pointer;border-radius:50%;flex:none;font-size:18px}.check-btn.done{background:var(--good);border-color:var(--good);color:#fff}@media (width<=800px){.classroom{grid-template-columns:1fr}.classroom-side{max-height:none;position:static}}.video-frame{background:#000;border-radius:12px;margin:20px 0;padding-top:56.25%;position:relative;overflow:hidden}.video-frame iframe{border:0;width:100%;height:100%;position:absolute;inset:0}.option{border:1px solid var(--border);cursor:pointer;border-radius:10px;align-items:center;gap:10px;margin-bottom:6px;padding:10px 12px;display:flex}.option.on{background:var(--pill)}.btn.done{background:var(--good);color:#fff;opacity:1}.tabs{border-bottom:1px solid var(--border);flex-wrap:wrap;gap:6px;margin:28px 0 16px;display:flex}.tab{color:var(--ink-soft);cursor:pointer;background:0 0;border:none;border-bottom:3px solid #0000;padding:10px 14px;font-size:14px;font-weight:600}.tab.active{color:var(--ink);border-bottom-color:var(--brand)}.comment{border-bottom:1px solid var(--border);padding:12px 0}.comment-head{align-items:center;gap:8px;margin-bottom:4px;display:flex}.tag{background:var(--brand-light);color:var(--brand-dark);border-radius:999px;padding:2px 8px;font-size:10px;font-weight:800}.like{border:1px solid var(--border);color:var(--ink-soft);cursor:pointer;background:0 0;border-radius:999px;margin-top:6px;padding:3px 10px;font-size:12px}.like.on{color:#d1342f;border-color:#d1342f}.like:disabled{cursor:default}.chat-box{border:1px solid var(--border);background:var(--bg);border-radius:12px;min-height:140px;max-height:340px;padding:12px;overflow-y:auto}.bubble{white-space:pre-wrap;border-radius:14px;max-width:85%;margin-bottom:8px;padding:9px 13px;font-size:14px;line-height:1.5}.bubble.user{background:var(--pill);margin-left:auto}.bubble.assistant{background:var(--surface);border:1px solid var(--border)}.bubble.error{color:#b91c1c}.chips{flex-wrap:wrap;gap:8px;margin-top:10px;display:flex}.chip{background:var(--surface);border:1px solid var(--border);cursor:pointer;border-radius:999px;padding:6px 12px;font-size:13px}.chip:hover{background:var(--pill)}.stats{flex-wrap:wrap;gap:8px;margin:14px 0;display:flex}.stats span{background:var(--bg);border:1px solid var(--border);border-radius:999px;padding:5px 12px;font-size:13px;font-weight:600}.tl-head{margin:12px 0 6px;font-weight:700}.tl-row{text-align:left;cursor:pointer;background:0 0;border:none;border-radius:10px;align-items:center;gap:12px;width:100%;padding:10px 12px;font-size:14px;display:flex}.tl-row:hover{background:#efece7}.tl-n{background:var(--bg);border:1px solid var(--border);border-radius:50%;flex:none;justify-content:center;align-items:center;width:26px;height:26px;font-size:12px;font-weight:700;display:flex}.tl-title{flex:1;min-width:0}.tl-dur{color:var(--ink-soft);font-size:12px}