:root{--bg:#0c1117;--panel:#151d26;--line:#2b3744;--text:#eaf0f5;--muted:#91a0ae;--accent:#99e66c}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--text);font:14px system-ui}
a{color:inherit;text-decoration:none}
header{height:64px;display:flex;align-items:center;gap:32px;padding:0 28px;border-bottom:1px solid var(--line);position:sticky;top:0;background:#0c1117ee;z-index:2}
.brand{font-weight:900;letter-spacing:.1em}
.brand span,small{color:var(--accent)}
nav{display:flex;gap:6px;flex:1}
nav a,header button{padding:9px 12px;border:0;border-radius:8px;background:none;color:var(--muted)}
nav a.active,nav a:hover{background:#1d2732;color:white}
main{max-width:1500px;margin:auto;padding:32px}
.head{display:flex;align-items:end;justify-content:space-between;margin-bottom:22px}
.head h1{font-size:34px;margin:4px 0}
.head-actions{display:flex;gap:12px;align-items:center}
.difficulty-badge{display:inline-flex;align-items:baseline;gap:7px;min-height:40px;padding:9px 12px;border:1px solid var(--line);border-radius:8px;color:var(--muted);white-space:nowrap}
.difficulty-badge strong{color:var(--text);font-size:16px}
.stats{display:grid;grid-template-columns:repeat(6,1fr);gap:14px;margin-bottom:20px}
.stats article,.panel,.card{background:var(--panel);border:1px solid var(--line);border-radius:14px}
.stats article{padding:18px}
.stats b{font-size:28px;display:block}
.stats span,p{color:var(--muted)}
.run-completed{color:var(--accent)}
.run-failed{color:#ff6b5f}
.run-failed+small{display:block;color:var(--muted);margin-top:4px}
.panel{overflow:auto;padding:18px}
.panel h2{margin-top:0}
table{width:100%;border-collapse:collapse}
th,td{text-align:left;padding:12px;border-bottom:1px solid var(--line);white-space:nowrap}
th{color:var(--muted);font-size:11px}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.card{overflow:hidden}
.thumb{width:100%;aspect-ratio:1/2;background:#090e13}
.copy{padding:16px}
.copy h2{margin:7px 0}
.split{display:grid;grid-template-columns:1fr 1.1fr;gap:18px}
.canvas{height:650px;background:#090e13}
.canvas canvas,.thumb canvas{width:100%;height:100%;display:block}
.panel-title,.filters{display:flex;gap:12px;align-items:center;justify-content:space-between}
.filters{justify-content:flex-start;background:var(--panel);padding:14px;border:1px solid var(--line);border-radius:12px;margin-bottom:18px}
input,select,.course-json{background:#0d141b;color:white;border:1px solid var(--line);border-radius:8px;padding:10px}
.primary,.secondary,.danger{display:inline-block;min-height:40px;padding:10px 15px;border:1px solid transparent;border-radius:8px;font-weight:800;cursor:pointer}
.primary{background:var(--accent);color:#14200e}
.secondary{background:#1d2732;color:var(--text);border-color:var(--line)}
.danger{background:#3b2025;color:#ffb6af;border-color:#6a3037}
button:disabled{cursor:wait;opacity:.6}
.course-json{display:block;width:100%;height:52vh;resize:vertical;font:12px/1.5 ui-monospace,SFMono-Regular,Menlo,monospace;tab-size:2}
.login-shell{min-height:90vh;display:grid;place-items:center}
.login-card{width:380px;display:flex;flex-direction:column;gap:15px;padding:30px;background:var(--panel);border:1px solid var(--line);border-radius:16px}
.login-card label{display:flex;flex-direction:column;gap:6px}
.login-card .primary{text-align:center;cursor:pointer}
.error{background:#52252d;padding:10px;border-radius:8px}

.editor-head{align-items:center}
.editor-introduction{max-width:72ch;margin:-10px 0 22px}
.course-editor-workspace{display:grid;grid-template-columns:250px minmax(360px,1fr) 310px;gap:16px;align-items:start}
.editor-toolbar,.editor-inspector{position:sticky;top:80px}
.editor-toolbar h2,.editor-inspector h2,.editor-stage h2{margin:0}
.tool-list{display:grid;gap:8px;margin-top:16px}
.editor-tool{display:flex;align-items:center;gap:10px;min-height:44px;width:100%;padding:9px 11px;border:1px solid var(--line);border-radius:9px;background:#101820;color:var(--muted);font:inherit;font-weight:750;text-align:left;cursor:pointer}
.editor-tool span{display:grid;place-items:center;width:24px;color:var(--text);font-size:17px}
.editor-tool:hover,.editor-tool.active{background:#22303b;color:var(--text);border-color:#566878}
.editor-tool.active{box-shadow:inset 0 0 0 1px var(--accent)}
.editor-control-group{display:grid;gap:8px;padding-top:18px;margin-top:18px;border-top:1px solid var(--line)}
.editor-control-group label,.inspector-grid label{display:grid;gap:6px;color:var(--muted);font-size:12px;font-weight:750}
.editor-control-group select{width:100%}
.editor-control-group p,.editor-stage-heading p,.editor-json-details p{font-size:12px;line-height:1.5;margin:0}
.compact-actions,.canvas-size-control,.inspector-actions{display:flex;gap:8px}
.compact-actions>*{flex:1;padding-inline:8px}
.canvas-size-control input{min-width:0;width:100%}
.editor-stage{min-width:0;overflow:visible}
.editor-stage-heading{display:flex;justify-content:space-between;gap:16px;align-items:start;margin-bottom:14px}
.editor-stage-heading h2{margin-bottom:5px}
.editor-key-hint{flex:none;color:var(--muted);font-size:11px;padding:5px 8px;border:1px solid var(--line);border-radius:6px}
.editor-stage-body{display:flex;justify-content:center;min-height:440px;padding:12px;background:#090e13;border:1px solid var(--line);border-radius:10px;overflow:auto}
.course-editor-canvas{flex:none;margin:auto;max-width:100%;background:#090e13;touch-action:none;outline:none}
.course-editor-canvas:focus-within{box-shadow:0 0 0 2px var(--accent)}
.course-editor-canvas canvas{cursor:crosshair}
.editor-message{min-height:20px;margin-top:10px;color:var(--muted)}
.error-text{color:#ff8d83}
.editor-inspector{display:grid;gap:16px}
.editor-empty{margin:0;line-height:1.55}
.inspector-heading{display:flex;justify-content:space-between;gap:8px;align-items:center;padding-bottom:10px;border-bottom:1px solid var(--line)}
.inspector-heading span{color:var(--muted);font-size:12px;text-transform:uppercase}
.inspector-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin:14px 0}
.inspector-grid input,.inspector-grid select{width:100%;min-width:0}
.inspector-actions{justify-content:space-between}
.editor-validation{padding:12px;border:1px solid var(--line);border-radius:9px;background:#101820}
.editor-validation.valid{border-color:#4f713e;background:#18251b}
.editor-validation.invalid{border-color:#6a3037;background:#2d1a1f}
.editor-validation ul{margin:8px 0 0;padding-left:18px;color:#ffb6af}
.editor-validation li+li{margin-top:5px}
.version-note{font-size:12px;line-height:1.5;margin:0}
.version-policy{display:grid;gap:8px;margin:0;padding:12px;border:1px solid var(--line);border-radius:9px}
.version-policy legend{padding:0 5px;font-weight:800}
.version-option{display:flex;gap:9px;align-items:flex-start;padding:9px;border:1px solid var(--line);border-radius:8px;background:#101820;cursor:pointer}
.version-option:has(input:checked){border-color:#566878;background:#1b2731}
.version-option input{margin:3px 0 0;padding:0;accent-color:var(--accent)}
.version-option span{display:grid;gap:3px}
.version-option small{color:var(--muted);line-height:1.4}
.destructive-option:has(input:checked){border-color:#6a3037;background:#2d1a1f}
.destructive-option:has(input:checked) small{color:#ffb6af}
.editor-json-details{margin-top:18px}
.editor-json-details summary{cursor:pointer;font-weight:800}
.editor-json-details[open] summary{margin-bottom:10px}
.editor-json-details .course-json{margin-top:12px}
button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:2px solid var(--accent);outline-offset:2px}

@media(max-width:1180px){
  .course-editor-workspace{grid-template-columns:230px minmax(360px,1fr)}
  .editor-inspector{position:static;grid-column:1/-1;grid-template-columns:minmax(260px,.8fr) minmax(320px,1.2fr);align-items:start}
  .editor-inspector>h2{grid-column:1/-1}
  .version-note{grid-column:1/-1}
}
@media(max-width:1000px){
  .stats{grid-template-columns:repeat(2,1fr)}
  .grid,.split{grid-template-columns:1fr}
}
@media(max-width:760px){
  .course-editor-workspace{grid-template-columns:1fr}
  .editor-toolbar,.editor-inspector{position:static;grid-column:auto;grid-template-columns:1fr}
  .editor-inspector>h2,.version-note{grid-column:auto}
  .editor-stage-body{min-height:360px}
  .editor-key-hint{display:none}
}
@media(max-width:650px){
  main{padding:20px 12px}
  .grid{grid-template-columns:1fr}
  header{padding:0 12px}
  .brand span{display:none}
  .head{align-items:flex-start;gap:14px;flex-direction:column}
  .head-actions{flex-wrap:wrap}
  .compact-actions,.inspector-actions{flex-wrap:wrap}
}