body {
    font-family: Arial, Helvetica, sans-serif;
    text-align: center;
    background: url("./mario-bg.jpg");
    background-size: cover;
}

#board {
    width: 540px;
    height: 540px;
    /* background-color: green; */

    margin: 0 auto;
    display: flex;
    flex-wrap: wrap;

    background: url("./soil.png");
    background-size: cover;
    border: 3px solid white;
    border-radius: 25px;
}

#board div {
    /* board = 540 x 540, divide into 3x3 tiles --> 180 x 180 per div */
    width: 180px; 
    height: 180px;
    background-image: url("./pipe.png");
    background-size: cover;
}

#board div img {
    /* all img tags inside tiles */
    width: 100px;
    height: 100px;

    user-select: none;
    -moz-user-select: none;
    -webkit-user-drag: none;
    -webkit-user-select: none;
    -ms-user-select: none;
}

#restart-btn {
    padding: 16px 34px;
    font-size: 26px;
    font-weight: bold;

    background: linear-gradient(to bottom, #ffe066, #ffcc00);
    color: #3b2f00;

    border: 3px solid #fff3b0;
    border-radius: 18px;

    cursor: pointer;
    display: none;

    position: fixed;
    top: 58%;
    left: 50%;
    transform: translate(-50%, -50%);

    box-shadow:
        0 0 20px rgba(255, 204, 0, 0.6),
        0 8px 20px rgba(0,0,0,0.35);

    transition: all 0.25s ease;

    z-index: 1000;
}

#restart-btn:hover {
    transform: translate(-50%, -50%) scale(1.08);
    background: linear-gradient(to bottom, #fff08a, #ffd633);
}

body::after {
    content: "";
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.25);
    pointer-events: none;
    opacity: 0;
    transition: 0.3s ease;
}

body.game-over::after {
    opacity: 1;
}