:root {
  --page-bg: #eef2eb;
  --panel-bg: #ffffff;
  --panel-border: #cfd8c9;
  --text: #203126;
  --muted: #5c6b5f;
  --button-bg: #2f6f4f;
  --button-text: #ffffff;
  --button-muted: #dbe6d8;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 1rem;
  background: var(--page-bg);
  color: var(--text);
  font-family: "Segoe UI", Tahoma, sans-serif;
}

.game-shell {
  width: min(100%, 42rem);
  padding: 1rem;
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
}

.game-header {
  display: grid;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

h1,
h2,
p {
  margin: 0;
}

.subtitle {
  margin-top: 0.25rem;
  color: var(--muted);
}

.hud {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  color: var(--muted);
}

.hud span {
  color: var(--text);
  font-weight: 700;
}

.actions,
.controls {
  display: grid;
  gap: 0.5rem;
}

.actions {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-bottom: 0.75rem;
}

button {
  border: 1px solid var(--panel-border);
  padding: 0.65rem 0.8rem;
  background: var(--panel-bg);
  color: var(--text);
  font: inherit;
}

#restart-btn,
#pause-btn {
  background: var(--button-muted);
}

.board-wrap {
  position: relative;
  border: 1px solid var(--panel-border);
  background: #f3f6ef;
}

#board {
  display: block;
  width: 100%;
  aspect-ratio: 1;
}

.overlay {
  position: absolute;
  inset: 0;
  display: grid;
  place-content: center;
  gap: 0.4rem;
  padding: 1rem;
  text-align: center;
  background: rgb(255 255 255 / 0.82);
}

.overlay[hidden] {
  display: none;
}

.controls {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 0.75rem;
}

.controls button {
  background: var(--button-bg);
  color: var(--button-text);
  border-color: var(--button-bg);
}

@media (min-width: 720px) and (pointer: fine) {
  .controls {
    display: none;
  }
}