:root {
    font-family: sans-serif;
    color-scheme: light dark;

    /* theme colours */
    --primary: #055;
    --secondary: #dee;
    --negative: #a01;
    --background: #eff;
    --foreground: #022;
    --behind: #dee;
    --header-bg: var(--primary);

    @media (prefers-color-scheme: dark) {
        --primary: #8cc;
        --secondary: #122;
        --negative: #e78;
        --background: #233;
        --foreground: #eff;
        --behind: #011;
        --header-bg: var(--secondary);
    }

    /* dimensions */
    --page-width: 800px;
    --is-wide: 1;
    @media (width < 800px) {
        --is-wide: 0;
    }
}

body {
    margin: 0;
    padding: 0;

    background-color: var(--behind);
}

header {
    background: linear-gradient(
        to bottom,
        color-mix(in oklab, var(--header-bg), var(--behind)),
        var(--header-bg)
    );
    color: contrast-color(var(--header-bg));

    padding: 1em;
    max-width: var(--page-width);
    margin: calc(var(--is-wide) * 1em) auto;
    height: 100px;
    display: flex;
    align-items: end;

    site-name {
        font-weight: bold;
        font-size: xx-large;
    }
}

footer {
    font-size: small;
    text-align: center;
    margin: 1lh;
    color: color-mix(in oklab, var(--foreground), var(--behind));

    a {
        color: inherit;
        text-decoration-style: dotted;
    }
}

main {
    padding: 1em;
    max-width: var(--page-width);
    margin: auto;
    background-color: var(--background);
    color: var(--foreground);

    &.challenge-page {
        display: flex;
        flex-direction: column;
        align-items: center;
    }
}

error-message {
    background-color: var(--negative);
    color: contrast-color(var(--negative));
    margin: 1em 0;
    padding: 1em;
    border-radius: 4px;
    display: flex;
    flex-direction: column;
    gap: 0.5lh;
    width: max-content;
    max-width: 100%;
    box-sizing: border-box;

    box-label {
        font-weight: bold;
    }
}

.challenge-message {
    border: 1px solid var(--negative);
    padding: 1em;
    width: max-content;
    max-width: 100%;
    box-sizing: border-box;
}

form {
    display: grid;
    grid-template-columns: max-content max-content;
    gap: 1em;
    background-color: var(--behind);
    margin: 1em 0;
    padding: 1em;
    width: max-content;
    max-width: 100%;
    box-sizing: border-box;

    button {
        grid-column: 1 / 3;
        width: max-content;
        justify-self: center;
    }

    p {
        grid-column: 1 / 3;
    }
}

challenge-separator {
    &::before, &::after {
        content: "—";
        padding: 0 1ex;
    }
}