:root {
  --bg: #0d1117;
  --bg-card: #161b22;
  --bg-editor: #0a0e14;
  --text: #c9d1d9;
  --text-sec: #6e7681;
  --text-muted: #3b4048;
  --accent: #58a6ff;
  --green: #3fb950;
  --red: #f85149;
  --border: rgba(88,166,255,0.06);
  --font: 'Fira Code',monospace;
  --radius: 8px;
  --transition: 0.2s ease;
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
body{font-family:var(--font);background:var(--bg);color:var(--text);min-height:100vh;overflow:hidden}

.header{display:flex;align-items:center;justify-content:space-between;padding:4px 12px;background:var(--bg-card);border-bottom:1px solid var(--border);height:36px}
.header-left,.header-right{display:flex;align-items:center;gap:8px}
.logo{font-size:1rem}
h1{font-size:0.82rem;font-weight:600;color:var(--accent)}
.fps{font-size:0.62rem;padding:2px 6px;border-radius:4px;background:rgba(63,185,80,0.08);color:var(--green)}

.btn,.select{padding:3px 8px;border:1px solid var(--border);border-radius:6px;background:transparent;color:var(--text-sec);font-family:var(--font);font-size:0.65rem;cursor:pointer;transition:all var(--transition)}
.btn:hover{border-color:var(--accent);color:var(--accent)}
.select:focus{outline:none;border-color:var(--accent)}

.app-layout{display:flex;height:calc(100vh - 36px)}
.editor-panel{flex:1;display:flex;flex-direction:column;min-width:300px;border-right:1px solid var(--border)}
.canvas-panel{flex:1;display:flex;background:#000}

.editor-tabs{display:flex;border-bottom:1px solid var(--border);background:var(--bg-card)}
.tab{padding:5px 14px;border:none;background:transparent;color:var(--text-muted);font-family:var(--font);font-size:0.68rem;cursor:pointer;border-bottom:2px solid transparent;transition:.2s}
.tab.active{color:var(--accent);border-bottom-color:var(--accent)}

.editor{flex:1;border:none;resize:none;background:var(--bg-editor);color:var(--text);font-family:var(--font);font-size:0.78rem;line-height:1.7;padding:10px 12px;tab-size:2;white-space:pre;overflow:auto}
.editor:focus{outline:none}

.error-bar{padding:4px 10px;background:rgba(248,81,73,0.06);border-top:2px solid var(--red);color:var(--red);font-size:0.68rem;max-height:80px;overflow-y:auto}

canvas{width:100%;height:100%;display:block}

@media(max-width:640px){
  .app-layout{flex-direction:column}
  .editor-panel{border-right:none;border-bottom:1px solid var(--border);max-height:50vh}
}