Fixed code overflow

In the theme’s /static/css/md.css everything below /* code blocks */ was altered to the following:

.md code {
    font-size: calc(0.85rem * var(--scale));
    padding: 0 0.25rem;
    background: var(--color-bg)
}

.md pre {
    overflow-x: scroll;
    background: var(--color-bg);
    scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-bg);
    scrollbar-width: thin;
    margin: 1rem 0;
    font-size: calc(0.8rem * var(--scale));
    padding: 0.5rem;
}

.md pre::-webkit-scrollbar {
    width: 1em;
}

.md pre::-webkit-scrollbar-track {
    background: var(--scrollbar-bg);
}

.md::-webkit-scrollbar-thumb {
    background-color: var(--scrollbar-thumb);
    border-radius: 6px;
    border: 3px solid var(--scrollbar-border);
}

Background color was added to easier distinguish code from prose.