:root {
  --bg: #020617;
  --surface: #0f172a;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --accent: #22c55e;
  --accent-strong: #16a34a;
  --danger: #f43f5e;
  --radius: 12px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  display: flex;
  justify-content: center;
  overflow-x: hidden;
}

.app {
  width: 100%;
  max-width: 440px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.title {
  margin: 8px 0 0;
  font-size: 2rem;
  letter-spacing: 0.3em;
  color: var(--accent);
}

.scoreboard {
  display: flex;
  justify-content: space-between;
  width: 100%;
  font-size: 1.05rem;
  font-variant-numeric: tabular-nums;
}

.scoreboard p {
  margin: 0;
}

.scoreboard span {
  font-weight: 700;
}

.board-wrapper {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1;
}

.board {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: 0 0 0 2px #1e293b;
}

.overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  border-radius: var(--radius);
  background: rgba(2, 6, 23, 0.6);
  text-align: center;
}

.overlay[hidden] {
  display: none;
}

.overlay p {
  margin: 0;
}

.overlay-title {
  font-size: clamp(1.6rem, 8vw, 2.4rem);
  font-weight: 800;
  letter-spacing: 0.1em;
  color: var(--danger);
}

.overlay-score {
  font-size: 1.2rem;
}

.restart {
  min-width: 160px;
  padding: 12px 24px;
  border: none;
  border-radius: var(--radius);
  background: var(--accent-strong);
  color: #fff;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  cursor: pointer;
}

.restart:hover {
  background: var(--accent);
}

.restart:focus-visible {
  outline: 3px solid var(--text);
  outline-offset: 3px;
}

.help {
  margin: 0;
  color: var(--muted);
  font-size: 0.85rem;
  text-align: center;
}

kbd {
  display: inline-block;
  padding: 0 6px;
  border: 1px solid #334155;
  border-radius: 4px;
  font-family: inherit;
  font-size: 0.8rem;
}

.version {
  color: var(--muted);
  font-size: 0.75rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  border: 0;
}