style.css

* {
    box-sizing: border-box;
}

body {
    font: 18px/1.5 "Helvetica", "Arial", sans-serif;
    margin: 0 0 4rem 0;
    padding: 0 10px;
}

h1,h2,h3,h4,h5,h6 {
    line-height: 1.2;
}

header,main,footer {
    margin: 0 auto;
    max-width: 800px;
    width: 100%;
}

a,a:visited {
    color: currentColor;
}
a:hover,a:focus {
    color: blue;
}

.referral {
    background: #27ae60;
    color: white;
    margin: 1rem 0 2rem;
    padding: 10px;
    text-align: center;
}
.referral p {
    margin: 0;
    padding: 0;
}
.referral a, .referral a:visited {
    color: white;
    font-weight: 600;
}
.referral a:hover, .referral a:focus {
    color: black;
}

ul {
    list-style: none;
    margin: 3rem 0 0 0;
    padding: 0;
}
ul li {
    background: rgba(0,0,0,0.05);
    line-height: 1;
    margin: 0 0 0.5rem 0;
    padding: 15px 10px 12px;
    position: relative;
}
ul li span.before,
ul li span.after {
    left: 0;
    position: absolute;
    top: 0;
}
ul li span.before {
    background: rgba(0,0,0,0.1);
    height: 100%;
    width: calc(var(--data-size)/1000 * 100%);
    z-index: 0;
}
ul li span.after {
    left: auto;
    opacity: 0.6;
    right: 10px;
    top: auto;
}
ul li a {
    font-weight: bold;
    position: relative;
    z-index: 2;
}

blockquote {
    background: blanchedalmond;
    border-left: 5px solid burlywood;
    margin: 3rem 0 2rem;
    padding: 20px;
}
blockquote h3 {
    margin-top: 0;
}
blockquote p {
    margin: 0;
}

main h3 {
    margin-top: 3rem;
    padding-top: 1rem;
}

footer {
    border-top: 1px solid lightgrey;
    margin: 3rem auto 0;
    padding: 0.5rem 0 0;
}
footer p {
    font-size: 85%;
}

/* Dark Theme */
@media (prefers-color-scheme: dark) {
    body {
        background: #2d2d2d;
        color: white;
    }
    blockquote {
        background: #191919;
        border-left: 5px solid black;
    }
    ul li {
        background: rgba(0,0,0,0.2);
    }
    ul li span.before {
        background: rgba(0,0,0,0.5);
    }
}

@media(max-width:500px) {
    body {
        font: 16px/1.5 "Helvetica", "Arial", sans-serif;
        margin: 0 0 4rem 0;
        padding: 0 10px;
    }
}