html,
body {
    width: 100%;
    height: 100%;

    padding: 0;
    margin: 0;
}

body {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

* {
    font-family:
        'Avenir Next',
        system-ui,
        -apple-system,
        BlinkMacSystemFont,
        'Segoe UI',
        Roboto,
        Oxygen,
        Ubuntu,
        Cantarell,
        'Open Sans',
        'Helvetica Neue',
        sans-serif;
    
    user-select: none;
}

.filler {
    flex-grow: 1;
}

#counter {
    font-size: 35vh;
    text-align: center;

    padding: 0;
    margin: 0;

    font-weight: normal;
}

button {
    border: none;
    border-radius: 4px;
    font-size: 1.1rem;
    outline: none;
    background-color: transparent;

    color: #000;

    font-weight: bold;

    cursor: pointer;

    padding: 8px 16px;
    margin: 0;

    transition: all 150ms ease;
}

button:active {
    background-color: #fff3;
    transform: scale(0.9);
}

#add {
    padding: 0;

    border-radius: 50%;

    width: 80px;
    height: 80px;

    position: relative;
}

#add::before,
#add::after {
    content: '';
    --width: 70%;
    --height: 10px;

    width: var(--width);
    height: var(--height);

    position: absolute;

    top: calc(50% - var(--height) / 2);
    left: calc(50% - var(--width) / 2);

    background-color: #000;

    border-radius: 4px;
}

#add::after {
    transform: rotate(90deg);
}

#buttons {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 48px;
}

@media (prefers-color-scheme: dark) {
    body {
        background-color: #333;
    }

    * {
        color: #fff !important;
    }

    #add::before,
    #add::after {
        background-color: #fff;
    }
}