body {
    display: flex;
    margin: 2rem;
    /* https://systemfontstack.com */
    font-family: Iowan Old Style, Apple Garamond, Baskerville, Times New Roman, Droid Serif, Times, Source Serif Pro, serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol;
}

header {
    flex: 0 0 16rem;
}

header h2 {
    margin-top: 0;
}

header h2 a {
    color: black;
}

header a {
    text-decoration: none;
}

header a:hover {
    text-decoration: underline;
}

nav a.active {
    font-weight: bold;
}

main {
    padding: 0 4rem;
}

main a:hover {
    text-decoration: none;
}

main h1 {
    margin-top: 0;
}

main h2 {
    margin-top: 3rem;
}

main h3 {
    margin-top: 2rem;
}

dt {
    font-size: 1.2rem;
    font-style: italic;
    margin: 16px 0 4px 0;
}

pre.highlight {
    background-color: #F5F5F5;
    border-radius: 0.5rem;
    padding: 1rem 0.5rem;
    max-width: 100%;
    overflow-x: auto;
}

code {
    font-family: "liberation mono","bitstream vera mono","dejavu mono",monospace;
    font-size: 0.8rem;
}

a.call-to-action {
    margin-top: 1rem;
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: linear-gradient(to bottom, #8ff08f 0%, #39ba42 52%, #228e2b 100%);
    color: #f4fff0;
    border-radius: 999px;
    border: 1px solid #1c7a25;
    box-shadow: 0 1px 0 #c9f9c7 inset, 0 -1px 0 rgba(0, 0, 0, 0.18) inset, 0 2px 6px rgba(20, 90, 28, 0.35);
    text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.28);
    text-decoration: none;
    font-family: "Trebuchet MS", "Verdana", "Tahoma", sans-serif;
    font-size: 0.875rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

a.call-to-action:hover {
    background: linear-gradient(to bottom, #9df69d 0%, #45ca4f 52%, #2ea93a 100%);
    box-shadow: 0 1px 0 #dcffd9 inset, 0 -1px 0 rgba(0, 0, 0, 0.18) inset, 0 3px 9px rgba(20, 90, 28, 0.38);
}

@media (max-width: 900px) {
    body {
        flex-direction: column;
        margin: 1rem;
    }

    header {
        flex: none;
        width: 100%;
        order: 2;
        margin-top: 2rem;
        padding-top: 2rem;
        border-top: 1px solid #ddd;
    }

    main {
        padding: 1rem 0;
        order: 1;
    }
}