:root {
  font-family: system-ui, Segoe UI, Roboto, Arial;
}
body {
  margin: 0;
  background: #f3f4f6;
  color: #111;
}
.app {
  max-width: 900px;
  margin: 24px auto;
  padding: 16px;
}
header h1 {
  margin: 0 0 12px;
}
.controls {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 12px;
}
.game {
  display: grid;
  gap: 8px;
}
.card {
  aspect-ratio: 1/1;
  padding: 8px;
  font-size: 28px;
  background: #fff;
  border-radius: 8px;
  border: 1px solid #ddd;
  cursor: pointer;
}
.card.matched {
  background: linear-gradient(90deg, #c6f6d5, #fff);
  cursor: default;
}
.sidebar {
  margin-top: 12px;
}