* {
    box-sizing: border-box;
}

html {
    font-size: 16px;
}

body {
    font-family: sans-serif;
    font-weight: bold;
    display: flex;
    flex-direction: column;
    align-items: center;
    height: 100vh;
    margin: 0;
    background: black;
    color: white;
}

h1 {
    font-size: 3rem;
    margin: 1rem 0;
}

#start {
    font-size: 2rem;
    padding: 0.5rem 1rem;
    border-radius: 1rem;
    margin: 1rem 0;
}

#score {
    font-size: 2rem;
    margin: 1rem 0;
}

#timer {
    width: 20rem;
    height: 1rem;
    background: green;
    border-radius: 0.5rem;
    margin: 1rem 0;
}

.container {
    display: flex;
    justify-content: space-around;
    width: 80%;
    height: 40%;
}

.side {
    width: 15rem;
    height: 15rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    border: 2px solid black;
    border-radius: 1rem;
    background: gray;
}

.grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    width: 20rem;
    height: 20rem;
}

.cell {
    font-size: 2rem;
    border: 1px solid black;
    border-radius: 0.5rem;
    cursor: pointer;
    background: gray;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    width: 6rem;
    height: 6rem;
    padding: 0.5rem;
}