style.css

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, sans-serif;
  background: linear-gradient(135deg, #2980b9, #6dd5fa);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.container {
  text-align: center;
  color: #fff;
}

#game-board {
  width: 300px;
  height: 300px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border: 3px solid #fff;
  border-radius: 12px;
  overflow: hidden;
}

.tile {
  background-image: url("https://picsum.photos/600");
  background-size: 300px 300px;
  cursor: pointer;
}

.tile.empty {
  background: rgba(0,0,0,0.3);
  cursor: default;
}

.hidden {
  display: none;
}