:root,:root[data-theme=dark]{--brand-color: #4f8bf0;--brand-text-color: #0d1117;--bg: #0f1216;--surface: #171b21;--surface-2: #1e242c;--line: #2a323d;--text: #e6edf3;--muted: #93a1b1;--stage: #0a0c0f;--danger: #e05252;--ok: #3fb950;--shadow: 0 1px 2px rgba(0, 0, 0, .5), 0 8px 24px rgba(0, 0, 0, .35);color-scheme:dark}:root[data-theme=light]{--brand-color: #2f6fdb;--brand-text-color: #ffffff;--bg: #f4f6f9;--surface: #ffffff;--surface-2: #f0f3f7;--line: #dfe3e8;--text: #1f2328;--muted: #5f6b7a;--stage: #11141a;--danger: #c0392b;--ok: #1a7f37;--shadow: 0 1px 2px rgba(0, 0, 0, .06), 0 4px 12px rgba(0, 0, 0, .05);color-scheme:light}:root{--radius: 10px;--radius-sm: 7px;--layout-max: 1180px;--room-max: 1720px}*{box-sizing:border-box}html,body{height:100%}body{margin:0;font-family:Pretendard,Apple SD Gothic Neo,system-ui,-apple-system,sans-serif;color:var(--text);background:var(--bg);-webkit-text-size-adjust:100%}h1,h2,h3{margin:0 0 .5em;line-height:1.3}h1{font-size:22px}h2{font-size:16px}p{margin:0 0 .75em;line-height:1.6}a{color:var(--brand-color)}label{display:block;font-size:13px;font-weight:600;margin:12px 0 5px}input[type=text],input[type=password],input[type=date],input[type=file],input:not([type]),select,textarea{width:100%;padding:11px 12px;font:inherit;color:inherit;background:var(--surface-2);border:1px solid var(--line);border-radius:var(--radius-sm)}:focus-visible{outline:2px solid var(--brand-color);outline-offset:1px}@media(max-width:640px){input,select,textarea{font-size:16px}}input[type=checkbox]{width:auto;margin-right:6px}label:has(input[type=checkbox]){display:flex;align-items:center;font-weight:400}button{display:inline-flex;align-items:center;justify-content:center;gap:6px;font:inherit;font-weight:600;white-space:nowrap;padding:10px 16px;min-height:40px;color:var(--brand-text-color);background:var(--brand-color);border:1px solid transparent;border-radius:var(--radius-sm);cursor:pointer}button:hover:not(:disabled){filter:brightness(1.08)}button:disabled{opacity:.4;cursor:not-allowed}button.ghost{color:var(--text);background:var(--surface-2);border-color:var(--line)}button.danger{color:#fff;background:var(--danger)}button.icon{padding:0;width:40px;min-height:40px}button.icon.on{color:var(--brand-color);background:color-mix(in srgb,var(--brand-color) 18%,var(--surface));border-color:color-mix(in srgb,var(--brand-color) 55%,transparent)}button.icon.off{color:#fff;background:var(--danger);border-color:transparent}[role=alert]{padding:11px 13px;border-radius:var(--radius-sm);background:color-mix(in srgb,var(--danger) 16%,var(--surface));border:1px solid color-mix(in srgb,var(--danger) 45%,transparent)}[role=status]{padding:11px 13px;border-radius:var(--radius-sm);font-size:14px;background:color-mix(in srgb,var(--brand-color) 14%,var(--surface));border:1px solid color-mix(in srgb,var(--brand-color) 40%,transparent)}table{width:100%;border-collapse:collapse;background:var(--surface);font-size:14px}th,td{padding:10px 12px;text-align:left;border-bottom:1px solid var(--line)}th{font-size:12px;color:var(--muted)}.scroll-x{overflow-x:auto;border-radius:var(--radius)}.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}.layout{min-height:100%;display:flex;flex-direction:column}.layout-header{display:flex;align-items:center;gap:10px;padding:10px 16px;background:var(--brand-color);color:var(--brand-text-color)}.layout-logo{height:26px;width:auto}.layout-name{font-size:17px;font-weight:700}.layout-header .spacer{flex:1}.layout-header button.icon{color:var(--brand-text-color);background:transparent;border-color:color-mix(in srgb,var(--brand-text-color) 35%,transparent)}.layout-main{flex:1;width:100%;max-width:var(--layout-max);margin:0 auto;padding:20px 16px}.layout-footer{padding:10px 16px;text-align:center;font-size:12px;color:var(--muted)}@media(min-width:600px){.layout-main{padding:24px 20px}h1{font-size:24px}}.course-list{list-style:none;margin:0;padding:0;display:grid;gap:10px}.course-item{display:flex;align-items:center;gap:12px;padding:14px 16px}.course-item>div{flex:1;min-width:0;display:flex;flex-direction:column;gap:2px}.course-title{font-weight:700}.room-meta{font-size:13px;color:var(--muted)}.enter-link{flex:0 0 auto;padding:10px 18px;border-radius:var(--radius-sm);background:var(--brand-color);color:var(--brand-text-color);font-weight:600;text-decoration:none;white-space:nowrap}.enter{max-width:430px;margin:0 auto}.enter-preview{aspect-ratio:4 / 3;width:100%;background:var(--stage);border-radius:var(--radius);overflow:hidden;display:grid;place-items:center;margin-bottom:14px;padding:12px}.enter-preview video{width:100%;height:100%;object-fit:cover;transform:scaleX(-1)}.enter form button[type=submit]{width:100%;margin-top:16px}.room{position:fixed;top:0;right:0;bottom:0;left:0;display:flex;flex-direction:column;background:var(--bg);overflow:hidden}.room-bar{flex:0 0 auto;display:flex;align-items:center;gap:8px;padding:8px 10px;background:var(--surface);border-bottom:1px solid var(--line)}.room-title{font-size:15px;font-weight:700;margin:0;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.room-bar .spacer{flex:1 1 auto}.room-actions{display:flex;align-items:center;gap:6px;flex:0 0 auto}.room-count{font-size:13px;color:var(--muted);white-space:nowrap}@media(max-width:560px){.room-count{display:none}}@media(max-width:460px){.room-title{display:none}}.room-body{flex:1 1 auto;min-height:0;display:flex;gap:10px;padding:10px}.room-stage{flex:1 1 auto;min-width:0;min-height:0;display:flex}.room-side{flex:0 0 clamp(200px,22vw,320px);min-height:0;display:flex;flex-direction:column}.room[data-side=closed] .room-side{display:none}.tiles{flex:1 1 auto;min-height:0;display:flex;flex-direction:column;gap:8px;padding:8px;background:var(--stage);border-radius:var(--radius);overflow-y:auto;-webkit-overflow-scrolling:touch}.tile{position:relative;margin:0;flex:0 0 auto;width:100%;background:var(--surface-2);border-radius:var(--radius-sm);overflow:hidden}.tile video,.tile .tile-off{display:block;width:100%;aspect-ratio:4 / 3}.tile video{object-fit:cover}.tile-off{display:grid;place-items:center;color:var(--muted);font-size:13px}.tile figcaption{position:absolute;left:0;right:0;bottom:0;padding:4px 7px;font-size:12px;color:#fff;background:linear-gradient(transparent,#000000b8);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.tile-actions{position:absolute;top:6px;right:6px;display:flex;gap:4px;opacity:0;transition:opacity .12s}.tile:hover .tile-actions,.tile:focus-within .tile-actions{opacity:1}.tile-actions button{padding:3px 7px;min-height:0;font-size:11px;background:#0000009e;color:#fff;border-color:#ffffff40}.tiles-empty{color:var(--muted);font-size:13px;padding:16px;margin:0;text-align:center}.book{flex:1 1 auto;min-width:0;min-height:0;display:flex;flex-direction:column;gap:8px;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:10px}.book-view{flex:1 1 auto;min-height:0;overflow-y:auto;overflow-x:hidden;border-radius:var(--radius-sm);background:#fff;-webkit-overflow-scrolling:touch}.book-page{position:relative;width:100%}.book-page>canvas{display:block;width:100%;height:auto}.follow-back{position:absolute;right:18px;bottom:62px;z-index:8;box-shadow:var(--shadow)}.book{position:relative}.book-nav{flex:0 0 auto;display:flex;align-items:center;gap:8px;overflow-x:auto}.book-nav::-webkit-scrollbar{height:0}.book-nav button{flex:0 0 auto}.book-nav .page-no{flex:0 0 auto;font-size:13px;color:var(--muted)}.room-chat{position:absolute;right:10px;bottom:10px;top:62px;width:min(84vw,340px);z-index:6;display:flex;flex-direction:column;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:10px}.room-chat h2{font-size:14px;color:var(--muted);margin:0}.room-chat-head{display:flex;align-items:center;gap:8px;margin-bottom:8px}.room-chat-head .spacer{flex:1}.chat-lines{flex:1 1 auto;min-height:0;list-style:none;margin:0 0 10px;padding:0;overflow-y:auto;font-size:14px}.chat-lines li{padding:4px 0;line-height:1.5;word-break:break-word}.chat-lines b{color:var(--brand-color);margin-right:6px}.chat-lines li.mine b{color:var(--muted)}.room-chat form{flex:0 0 auto;display:flex;gap:6px}.room-chat form label{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}.badge{position:absolute;top:-4px;right:-4px;min-width:17px;height:17px;padding:0 4px;display:grid;place-items:center;font-size:11px;font-weight:700;color:#fff;background:var(--danger);border-radius:9px}.has-badge{position:relative;overflow:visible}.room-notice{flex:0 0 auto;margin:0 10px;font-size:13px;padding:7px 11px}.rotate-hint{display:none}@media(max-width:560px)and (orientation:portrait){.rotate-hint{display:block}}@media(max-width:899px)and (orientation:portrait){.room-body{flex-direction:column}.room-side{flex:0 0 auto}.tiles{flex-direction:row;overflow-x:auto;overflow-y:hidden;max-height:none}.tile{width:auto;flex:0 0 clamp(104px,27vw,150px)}}@media(min-width:640px)and (max-width:899px)and (orientation:portrait){.room-body{flex-direction:row}.room-side{flex:0 0 clamp(180px,24vw,240px)}.tiles{flex-direction:column;overflow-x:visible;overflow-y:auto}.tile{width:100%;flex:0 0 auto}}@media(max-width:899px)and (orientation:landscape){.room-side{flex:0 0 clamp(140px,22vw,220px)}}@media(min-width:900px){.room-body{gap:12px;padding:12px}.room-chat{position:static;width:clamp(240px,22vw,340px);flex:0 0 auto}}@media(min-width:1280px){.room-bar{padding:10px 16px}.room-body{gap:14px;padding:14px}}@media(hover:none){.tile-actions{opacity:1}button{min-height:44px}button.icon{width:44px}}@media(prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}.board{position:relative;width:100%;aspect-ratio:4 / 3;color:#1f6feb}.book-page>.board{position:absolute;top:0;right:0;bottom:0;left:0;width:auto;aspect-ratio:auto;z-index:2}.board-grid{background-image:repeating-linear-gradient(to right,rgba(0,0,0,.08) 0 1px,transparent 1px 40px),repeating-linear-gradient(to bottom,rgba(0,0,0,.08) 0 1px,transparent 1px 40px)}.board-ink{position:absolute;top:0;right:0;bottom:0;left:0;width:100%;height:100%;pointer-events:none}.watermark{position:absolute;top:0;right:0;bottom:0;left:0;overflow:hidden;pointer-events:none;z-index:1}.watermark span{position:absolute;color:#00000017;font-size:13px;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;white-space:nowrap;transform:rotate(-30deg);-webkit-user-select:none;user-select:none}.ink-halo{stroke:#ffffffd9}