:root{
  --bg:#0f1117; --panel:#1a1d27; --panel-2:#232733; --text:#e6e8ee;
  --muted:#9aa0ad; --accent:#7c5cff; --accent-2:#00d4aa; --border:#2c3140;
  --shadow:0 10px 30px rgba(0,0,0,.4);
}
[data-theme="light"]{
  --bg:#f3f4f8; --panel:#ffffff; --panel-2:#eef0f6; --text:#1b1e27;
  --muted:#5c6270; --accent:#7c5cff; --accent-2:#00b896; --border:#e0e3ec;
  --shadow:0 10px 30px rgba(20,30,60,.12);
}

*{box-sizing:border-box}
html,body{margin:0;height:100%}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg); color:var(--text);
  display:flex; flex-direction:column; min-height:100vh;
}

.topbar{
  display:flex; align-items:center; justify-content:space-between;
  padding:14px 22px; border-bottom:1px solid var(--border);
  background:var(--panel);
}
.logo{font-size:1.25rem; margin:0; letter-spacing:.3px}
.topbar-actions{display:flex; gap:8px}
.icon-btn{
  background:var(--panel-2); border:1px solid var(--border); color:var(--text);
  width:40px; height:40px; border-radius:10px; cursor:pointer; font-size:1.1rem;
  transition:transform .15s, background .15s;
}
.icon-btn:hover{transform:translateY(-2px); background:var(--accent); color:#fff}

.layout{
  flex:1; display:grid; grid-template-columns:1.3fr 1fr; gap:18px;
  padding:18px; max-width:1200px; width:100%; margin:0 auto;
}
@media (max-width:880px){ .layout{grid-template-columns:1fr} }

.panel{
  background:var(--panel); border:1px solid var(--border);
  border-radius:16px; box-shadow:var(--shadow); padding:16px;
  display:flex; flex-direction:column;
}

.cube-panel{min-height:420px}
.cube-canvas{flex:1; min-height:360px; border-radius:12px; overflow:hidden;
  background:radial-gradient(circle at 50% 30%, var(--panel-2), var(--panel));}
.cube-canvas canvas{display:block}
.cube-hint{text-align:center; color:var(--muted); font-size:.82rem; margin-top:8px}

.playback{display:flex; align-items:center; gap:10px; justify-content:center; margin-top:12px}
.progress{color:var(--muted); font-variant-numeric:tabular-nums; min-width:60px; text-align:center}

.tabs{display:flex; gap:6px; margin-bottom:14px}
.tab{
  flex:1; padding:10px; border:1px solid var(--border); background:var(--panel-2);
  color:var(--muted); border-radius:10px; cursor:pointer; font-weight:600;
}
.tab.active{background:var(--accent); color:#fff; border-color:var(--accent)}

.help{color:var(--muted); font-size:.88rem; margin:0 0 12px}

.palette{display:flex; gap:8px; flex-wrap:wrap; margin-bottom:14px}
.swatch{
  width:38px; height:38px; border-radius:10px; cursor:pointer;
  border:3px solid transparent; transition:transform .12s;
}
.swatch:hover{transform:scale(1.08)}
.swatch.selected{border-color:var(--text); box-shadow:0 0 0 2px var(--panel)}

.net{
  display:grid; grid-template-columns:repeat(12,1fr); gap:3px;
  width:100%; max-width:360px; margin:0 auto 14px; aspect-ratio:4/3;
}
.facelet{
  border-radius:4px; cursor:pointer; border:1px solid rgba(0,0,0,.25);
  transition:transform .08s;
}
.facelet:hover{transform:scale(1.06)}
.facelet.center{cursor:not-allowed; outline:2px solid rgba(255,255,255,.25)}

.row{display:flex; gap:8px; flex-wrap:wrap; margin-top:6px}
.pill{
  flex:1; min-width:110px; padding:11px 14px; border-radius:11px; cursor:pointer;
  border:1px solid var(--border); background:var(--panel-2); color:var(--text);
  font-weight:600; transition:transform .12s, background .15s;
}
.pill:hover{transform:translateY(-2px)}
.pill.primary{background:var(--accent); color:#fff; border-color:var(--accent)}
.pill:disabled{opacity:.5; cursor:not-allowed; transform:none}

.validation{margin-top:12px; font-size:.86rem; min-height:20px}
.validation.ok{color:var(--accent-2)}
.validation.err{color:#ff6b6b}

.stats{display:flex; gap:12px; margin-bottom:14px}
.stat{
  flex:1; background:var(--panel-2); border:1px solid var(--border);
  border-radius:12px; padding:12px; text-align:center;
}
.stat-num{display:block; font-size:1.5rem; font-weight:700}
.stat-label{color:var(--muted); font-size:.78rem}

.solution-moves{display:flex; flex-wrap:wrap; gap:6px; margin-bottom:16px}
.move-chip{
  padding:8px 12px; border-radius:9px; background:var(--panel-2);
  border:1px solid var(--border); font-weight:700; font-family:ui-monospace,monospace;
  min-width:42px; text-align:center;
}
.move-chip.active{background:var(--accent); color:#fff; border-color:var(--accent)}
.move-chip.done{opacity:.45}

.legend{color:var(--muted); font-size:.85rem}
.legend summary{cursor:pointer; font-weight:600; color:var(--text)}
.legend ul{padding-left:18px; line-height:1.7}
.legend code{background:var(--panel-2); padding:1px 6px; border-radius:5px}

.toast{
  position:fixed; bottom:24px; left:50%; transform:translateX(-50%);
  background:var(--accent); color:#fff; padding:12px 20px; border-radius:12px;
  box-shadow:var(--shadow); font-weight:600; z-index:50;
}