:root {
  color-scheme: dark;
  --bg: #0c0e12;
  --panel: #15181f;
  --panel-2: #1b1f28;
  --border: #2b313d;
  --text: #f4f6fb;
  --muted: #9ba5b5;
  --accent: #67d69b;
  --accent-2: #9ce8bd;
  --danger: #ff7d7d;
  --shadow: 0 18px 50px rgba(0,0,0,.28);
}

* { box-sizing: border-box; }
html, body { min-height: 100%; }
body {
  margin: 0;
  background:
    radial-gradient(circle at 20% 0%, rgba(103,214,155,.09), transparent 28rem),
    radial-gradient(circle at 90% 15%, rgba(91,143,249,.08), transparent 24rem),
    var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
}
button { font: inherit; }

.topbar {
  min-height: 78px;
  padding: 14px clamp(16px, 4vw, 44px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid rgba(255,255,255,.07);
  background: rgba(12,14,18,.78);
  backdrop-filter: blur(16px);
  position: sticky;
  top: 0;
  z-index: 10;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 42px; height: 42px; display: grid; place-items: center;
  border-radius: 12px; background: var(--accent); color: #062315;
  font-weight: 900; font-size: 25px; box-shadow: 0 8px 25px rgba(103,214,155,.22);
}
h1 { margin: 0; font-size: clamp(18px, 3vw, 24px); letter-spacing: .01em; }
.brand p { margin: 3px 0 0; color: var(--muted); font-size: 13px; }
.dataset-badge {
  color: var(--accent-2); border: 1px solid rgba(103,214,155,.35);
  background: rgba(103,214,155,.08); border-radius: 999px; padding: 7px 12px;
  font-weight: 700; font-size: 13px;
}

.app-shell { width: min(1050px, calc(100% - 28px)); margin: 28px auto 48px; }
.controls-card, .scramble-card, .solver-card, .notes-card {
  border: 1px solid var(--border); background: rgba(21,24,31,.94);
  border-radius: 18px; box-shadow: var(--shadow);
}
.controls-card { padding: 18px; display: grid; gap: 12px; }
.control-label { color: var(--muted); font-size: 14px; font-weight: 700; }
.step-selector { display: grid; grid-template-columns: repeat(5, 1fr); gap: 8px; }
.step-btn {
  min-height: 48px; border-radius: 12px; border: 1px solid var(--border);
  background: var(--panel-2); color: var(--text); cursor: pointer; font-weight: 900;
  font-size: 18px; transition: transform .15s ease, border-color .15s ease, background .15s ease;
}
.step-btn:hover { transform: translateY(-1px); border-color: #465064; }
.step-btn.active { color: #062315; background: var(--accent); border-color: var(--accent); }
.pool-info { color: var(--muted); font-size: 13px; min-height: 18px; }

.scramble-card { margin-top: 18px; padding: clamp(18px, 4vw, 36px); text-align: center; }
.scramble-topline { display: flex; justify-content: space-between; color: var(--muted); font-size: 13px; }
.scramble {
  min-height: 170px; padding: 28px 8px; display: flex; align-items: center; justify-content: center;
  font-size: clamp(30px, 6vw, 58px); line-height: 1.35; letter-spacing: .04em; font-weight: 700;
  word-spacing: .2em; text-wrap: balance; outline: none;
}
.scramble:focus-visible { border-radius: 12px; box-shadow: inset 0 0 0 2px var(--accent); }
.badges { display: flex; flex-wrap: wrap; justify-content: center; gap: 8px; }
.badge { border: 1px solid var(--border); color: #cbd2de; background: #11141a; padding: 7px 10px; border-radius: 999px; font-size: 13px; }
.badge-primary { color: var(--accent-2); border-color: rgba(103,214,155,.3); }

.toolbar { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; margin: 14px 0; }
.tool-btn {
  min-height: 48px; border-radius: 12px; border: 1px solid var(--border);
  background: var(--panel); color: var(--text); cursor: pointer; font-weight: 800;
}
.tool-btn:hover:not(:disabled) { border-color: #4b566b; background: #1b2029; }
.tool-btn:disabled { opacity: .4; cursor: not-allowed; }
.tool-btn-accent { background: var(--accent); color: #062315; border-color: var(--accent); }
.tool-btn-accent:hover:not(:disabled) { background: var(--accent-2); border-color: var(--accent-2); }

.solver-card { overflow: hidden; }
.solver-card summary { cursor: pointer; padding: 18px 20px; font-weight: 900; list-style: none; }
.solver-card summary::-webkit-details-marker { display: none; }
.solver-card summary::after { content: "＋"; float: right; color: var(--accent); }
.solver-card[open] summary::after { content: "－"; }
.solver-grid { border-top: 1px solid var(--border); padding: 18px; display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.solver-item { background: #11141a; border: 1px solid #262c37; border-radius: 12px; padding: 14px; display: grid; gap: 8px; }
.solver-wide { grid-column: 1 / -1; }
.solver-label { color: var(--muted); font-size: 12px; }
.solver-item strong { font-size: 17px; }
.solver-item code { font-size: clamp(18px, 4vw, 27px); color: var(--accent-2); white-space: normal; word-spacing: .25em; }
.notes-card { margin-top: 14px; padding: 16px 18px; color: var(--muted); font-size: 13px; line-height: 1.65; }
.notes-card p { margin: 4px 0; }
.notes-card strong { color: #dce2ec; }
.toast {
  position: fixed; left: 50%; bottom: 26px; transform: translate(-50%, 20px);
  background: #f3f6fa; color: #111820; padding: 10px 15px; border-radius: 999px;
  font-weight: 800; opacity: 0; pointer-events: none; transition: .2s ease; box-shadow: 0 12px 30px rgba(0,0,0,.35);
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }

@media (max-width: 720px) {
  .topbar { min-height: 68px; }
  .dataset-badge { display: none; }
  .app-shell { width: min(100% - 18px, 1050px); margin-top: 14px; }
  .toolbar { grid-template-columns: repeat(2, 1fr); }
  .scramble { min-height: 145px; padding: 22px 4px; }
  .solver-grid { grid-template-columns: 1fr; }
  .solver-wide { grid-column: auto; }
}
html,body{min-height:100%}.auth-gate{min-height:100vh;display:grid;place-items:center;padding:24px;background:#111318}.auth-gate[hidden]{display:none}.auth-card{width:min(420px,100%);padding:32px;border:1px solid #343946;border-radius:18px;background:#191c23;text-align:center;box-shadow:0 22px 60px rgba(0,0,0,.35)}.auth-mark{font-size:42px;color:#7692ff}.auth-card h1{margin:10px 0 6px}.auth-card p,.auth-card small{color:#aeb5c5}.auth-card input{box-sizing:border-box;width:100%;margin:20px 0 12px;padding:14px;border:1px solid #50586b;border-radius:11px;background:#0f1117;color:#fff;font-size:17px;text-transform:uppercase}.auth-card button{width:100%;padding:13px;border:0;border-radius:11px;background:#7692ff;color:#fff;font-size:17px;font-weight:700;cursor:pointer}.auth-message{min-height:24px;margin-top:10px;color:#ff7d87}
.top-actions{display:flex;align-items:center;gap:10px}.logout-btn{padding:8px 12px;border:1px solid #3d4350;border-radius:9px;background:transparent;color:#aeb5c5;cursor:pointer}