body {
  background: #f9fafc;
  color: #333;
  font-family: "Segoe UI", sans-serif;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header {
  background: #3f51b5;
  color: #fff;
  padding: 1rem;
  text-align: center;
}

header nav a {
  color: #fff;
  margin: 0 1rem;
  text-decoration: none;
  font-weight: bold;
}

main {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 2rem;
}

.controls {
  margin-bottom: 1rem;
}

button, select {
  padding: 0.5rem 1rem;
  margin: 0 0.5rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
}

button {
  background: #3f51b5;
  color: white;
}

button:hover {
  background: #303f9f;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  grid-template-rows: repeat(3, 100px);
  gap: 5px;
}

.cell {
  background: #fff;
  border: 2px solid #3f51b5;
  font-size: 2rem;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
}

.cell.taken {
  cursor: default;
}

.status {
  margin-top: 1rem;
  font-size: 1.2rem;
  font-weight: bold;
}

footer {
  background: #eee;
  text-align: center;
  padding: 1rem;
}