:root {
    --letterRotation: 0deg;
    --letterSize: 1;
    --hue: 0;
}

html {
    background-color: lemonchiffon;
}

#content {
    display: flex;
    flex-flow: row wrap;
}

.letter {
    display: inline-block;
    font-size: clamp(12px, calc(14px * var(--letterSize)), 5rem);
    display: flex;
    justify-content: center;
    align-items: center;
    line-height: .5;
    width: calc(10px * var(--letterSize));
    height: calc(10px * var(--letterSize));
    background-color: hsl(var(--hue), 100%, 50%);
    transform: rotate(var(--letterRotation));
    border-radius: 50%;
    box-shadow: 0 1px 10px rgba(0, 0, 0, .1);
}