:root {
  --bg: #f4efe6;
  --bg-accent: #e2d4bf;
  --panel: rgba(255, 251, 245, 0.84);
  --text: #1f1b16;
  --muted: #6c6256;
  --primary: #1d6b4f;
  --primary-strong: #124a37;
  --danger: #b4432f;
  --line: rgba(31, 27, 22, 0.12);
  --shadow: 0 20px 60px rgba(63, 45, 24, 0.18);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Avenir Next", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(255, 255, 255, 0.75), transparent 32%),
    radial-gradient(circle at bottom right, rgba(29, 107, 79, 0.16), transparent 28%),
    linear-gradient(135deg, var(--bg), var(--bg-accent));
}

.app {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  min-height: 100vh;
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 28px;
  align-items: center;
  padding: 32px 0;
}

.panel,
.board-shell {
  border: 1px solid rgba(255, 255, 255, 0.55);
  border-radius: 28px;
  background: var(--panel);
  backdrop-filter: blur(16px);
  box-shadow: var(--shadow);
}

.panel {
  padding: 28px;
}

.eyebrow {
  margin: 0 0 10px;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 12px;
  color: var(--primary);
  font-weight: 700;
}

h1 {
  margin: 0;
  font-size: clamp(36px, 6vw, 56px);
  line-height: 0.95;
}

.intro {
  margin: 16px 0 0;
  color: var(--muted);
  line-height: 1.6;
}

.stats {
  display: grid;
  gap: 12px;
  margin: 24px 0;
}

.stat-card {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 18px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid var(--line);
}

.stat-label {
  color: var(--muted);
}

.stat-card strong {
  font-size: 22px;
}

.actions {
  display: grid;
  gap: 12px;
}

button {
  border: 0;
  border-radius: 999px;
  padding: 14px 18px;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  transition: transform 140ms ease, opacity 140ms ease, background-color 140ms ease;
}

button:hover {
  transform: translateY(-1px);
}

button:active {
  transform: translateY(1px);
}

#start-btn,
#restart-btn {
  color: #fff8f0;
  background: linear-gradient(135deg, var(--primary), var(--primary-strong));
}

#pause-btn {
  color: var(--text);
  background: rgba(255, 255, 255, 0.86);
  border: 1px solid var(--line);
}

.tips {
  margin: 22px 0 0;
  padding-left: 18px;
  color: var(--muted);
  line-height: 1.6;
}

.board-shell {
  position: relative;
  display: grid;
  place-items: center;
  padding: 24px;
  min-height: 540px;
}

canvas {
  width: min(100%, 480px);
  height: auto;
  border-radius: 24px;
  background:
    linear-gradient(rgba(255, 255, 255, 0.04), rgba(255, 255, 255, 0.04)),
    linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(135deg, #17372c, #10261e);
  background-size: 100% 100%, 24px 24px, 24px 24px, 100% 100%;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.08);
}

.overlay {
  position: absolute;
  inset: 24px;
  display: grid;
  place-content: center;
  gap: 10px;
  text-align: center;
  border-radius: 24px;
  background: rgba(10, 19, 15, 0.56);
  color: #fff8f0;
  padding: 24px;
}

.overlay.hidden {
  display: none;
}

.overlay h2,
.overlay p {
  margin: 0;
}

.overlay h2 {
  font-size: clamp(28px, 4vw, 40px);
}

.overlay p {
  color: rgba(255, 248, 240, 0.82);
  line-height: 1.6;
  max-width: 28ch;
}

@media (max-width: 920px) {
  .app {
    grid-template-columns: 1fr;
    padding: 20px 0 28px;
  }

  .board-shell {
    min-height: auto;
  }
}