:root {
    --margin: 1em;
    --num-columns: 3;

    background-color: lightgray;
    font-family: Arial, Helvetica, sans-serif;
}

body {
    margin: 0;
    padding: 0;
}

h1 {
    margin-top: 0;
    text-align: center;
}

h2 {
    display: inline-block;
}

main {
    margin: var(--margin) auto;
    background-color: white;
    width: calc(100vw - var(--margin) * 2);
    max-width: 700px;
    padding: 0.5em;
    box-sizing: border-box;
    border-radius: 0.25em;
}

.alg-set {
    display: grid;
    grid-template-columns: repeat(var(--num-columns), 1fr);
    gap: 0.25em;
}

.alg-set h3, .alg-set p {
    margin: 0;
}

.alg-set img {
    width: 100%;
    border: 0.1em solid black;
    box-sizing: border-box;
}