* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: #f4f4f4;
}

.container {
    text-align: center;
}

h1 {
    margin-bottom: 20px;
    font-size: 24px;
}

.board {
    display: grid;
    grid-template-columns: repeat(3, 100px);
    grid-template-rows: repeat(3, 100px);
    gap: 5px;
    margin-bottom: 15px;
}

.cell {
    width: 100px;
    height: 100px;
    display: flex;
    justify-content: center;
    align-items: center;
    background: #fff;
    border: 2px solid #ccc;
    font-size: 2.5rem;
    cursor: pointer;
    transition: background 0.3s;
}

.cell:hover {
    background: #eaeaea;
}

button {
    padding: 10px 20px;
    font-size: 16px;
    border: none;
    background: #333;
    color: #fff;
    cursor: pointer;
    border-radius: 5px;
}

button:hover {
    background: #555;
}

.o {
    color: green;
}

.x {
    color: red;
}