:root {
  --bg: #f4f6f8;
  --card-bg: #ffffff;
  --border: #dde3ea;
  --text: #1f2933;
  --muted: #6b7684;
  --accent: #2f7cc9;
  --accent-dark: #1f5c99;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  padding: 24px;
}

.card {
  width: 100%;
  max-width: 380px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px 24px;
  text-align: center;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

h1 {
  margin: 0;
  font-size: 1.5rem;
}

.subtitle {
  margin: 6px 0 24px;
  color: var(--muted);
  font-size: 0.88rem;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin: 0 auto 18px;
  max-width: 300px;
}

.cell {
  aspect-ratio: 1 / 1;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.2rem;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.15s ease;
}

.cell:hover:not(.taken) {
  background: #eef2f6;
}

.cell.taken {
  cursor: default;
}

.cell.mark-cow {
  color: var(--accent);
}

.cell.mark-bull {
  color: var(--muted);
}

.status {
  min-height: 24px;
  font-weight: 600;
  margin: 6px 0 18px;
}

button#reset {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 10px;
  padding: 12px 20px;
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.15s ease;
}

button#reset:hover {
  background: var(--accent-dark);
}