body {


    font-family: Verdana, serif;
}

* {
    box-sizing: border-box;
}

:root {
    --border-radius-value: 10px;
    --box-shadow-value: 0 5px 15px rgba(0, 0, 0, 0.3);
    --light-grey: #c0c0c0;
    --green: #4caf50;
}

.card {
    background: #FEA176;
    width: 100px;
    height: 100px;
    border-radius: var(--border-radius-value);
    cursor: pointer;
    box-shadow: var(--box-shadow-value);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 36px;

    transition: all 600ms;

    & span {
        visibility: hidden;
        transform: rotateY(-180deg);
    }

    &.flipped {
        background: white;
        transform: rotateY(180deg);

        & span {
            visibility: visible;
        }

    }

    &.matched {
        background: var(--green);
        cursor: default;
    }
}

.controls {
    border-radius: var(--border-radius-value);
    box-shadow: var(--box-shadow-value);
    width: 80dvw;
    padding: 20px;
    border: 1px solid var(--light-grey);
    display: flex;
    align-items: center;
    margin: 5px auto 40px;


    .button-success {
        margin-left: auto;
    }
}

label {
    font-size: 18px;
    margin-left: 5px;

}

input {
    width: 100px;
    padding: 6px 8px;
    border-radius: 8px;
    border: 1px solid var(--light-grey);
    margin-right: 40px;
}

.button-success {
    background: var(--green);
    cursor: pointer;
    width: 150px;
    height: 40px;
    color: white;
    font-size: 16px;
    border: 1px solid var(--light-grey);
    border-radius: var(--border-radius-value);
    transition: all 0.3ms;

    &:hover {
        background: #3b8c3f;
    }
}

.board {
    display: grid;
    gap: 10px;
    margin: 5px auto 40px;
}

.counter {
    border-radius: var(--border-radius-value);
    box-shadow: var(--box-shadow-value);
    width: 40dvw;
    padding: 20px;
    border: 1px solid var(--light-grey);
    text-align: center;
    margin: 5px auto;

    visibility: hidden;
}