style.css

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-image: url(./idosa.png);
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
    padding: 10px;
}

#tabuleiro {
    width: 500px;
    background-color: #00000090;
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    flex-wrap: wrap;
    padding: 16px;
    border-radius: 10px;
    gap: 2px;
}

#tabuleiro .casa {
    width: 100%;
    height: 166px;
    border: 1px solid #ccc;
    position: relative;
    transition: 0.2s ease-in-out;
}

#tabuleiro .casa:hover {
    background-color: #ccc8;
}

#tabuleiro .casa.bola::after {
    content: "";
    width: 80px;
    height: 80px;
    border: 15px solid black;
    border-radius: 100%;
    box-sizing: border-box;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

#tabuleiro .casa.xis::after {
    content: "";
    width: 20px;
    height: 80px;
    background-color: red;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) skewX(30deg);
}

#tabuleiro .casa.xis::before {
    content: "";
    width: 20px;
    height: 80px;
    background-color: red;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) skewX(-30deg);
}

#resultado {
    width: 100%;
    height: 100%;
    backdrop-filter: blur(2px);
    background-color: #00000070;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    visibility: hidden;
}

#resultado.active {
    visibility: visible;
    opacity: 1;
}

#resultado h1 {
    padding: 50px;
    background-color: white;
    border-radius: 10px;
}