:root {
  --bg: #101827;
  --panel: rgba(18, 31, 58, 0.88);
  --line: rgba(226, 232, 240, 0.18);
  --text: #f8fafc;
  --muted: #b6c2d2;
  --cyan: #22d3ee;
  --amber: #f59e0b;
}

* { box-sizing: border-box; }

html,
body {
  margin: 0;
  min-height: 100%;
  font-family: "Segoe UI", Tahoma, sans-serif;
  color: var(--text);
  background:
    linear-gradient(135deg, rgba(37, 99, 235, 0.2), transparent 34%),
    linear-gradient(225deg, rgba(20, 184, 166, 0.17), transparent 31%),
    linear-gradient(180deg, #16213a, #101827 62%, #0d1424);
}

.shell { width: min(1000px, 100%); margin: 0 auto; padding: 12px; }
.topbar { display: flex; justify-content: space-between; align-items: flex-start; gap: 10px; }
.topbar h1 { margin: 0; font-size: clamp(1.35rem, 3vw, 2rem); letter-spacing: 0; }
.topbar p { margin: 4px 0 0; color: var(--muted); font-size: 0.92rem; }

button { border: 0; border-radius: 8px; color: #fff; font-weight: 800; cursor: pointer; min-height: 40px; }
#restartBtn { background: linear-gradient(135deg, var(--amber), #d97706); padding: 9px 14px; white-space: nowrap; }

.hud { margin: 12px 0; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; }
.chip { border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; display: flex; justify-content: space-between; gap: 8px; background: var(--panel); }
.chip span { color: var(--muted); overflow-wrap: anywhere; }

.reward-bar { margin: 0 0 10px; display: flex; flex-wrap: wrap; align-items: center; gap: 10px; }
#rewardBtn { background: linear-gradient(135deg, #0ea5e9, #2563eb); padding: 10px 14px; }
#rewardBtn:disabled { opacity: 0.55; cursor: not-allowed; }
.reward-note { margin: 0; color: var(--muted); font-size: 0.88rem; }
.stage-shell { width: 100%; aspect-ratio: 16 / 9; border: 1px solid var(--line); border-radius: 8px; overflow: hidden; background: #0c1730; box-shadow: 0 22px 56px rgba(2, 8, 23, 0.34); }
#game-stage, #game-stage canvas { width: 100%; height: 100%; display: block; }
.tip { margin: 9px 0 0; text-align: center; color: var(--muted); font-size: 0.85rem; }

@media (max-width: 760px) { .hud { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 480px) { .topbar { display: grid; } .hud { grid-template-columns: 1fr; } }