Suggest to max-width of markdown content

[ldmik]

The suggestion refers to below style:

.github-markdown-content {
    padding: 32px !important;
    max-width: 980px;
    min-width: 200px;
    margin: 0 auto;
}

When limited max-width, and you have big mermaid diagram presented, even though you have big screen, you still can't enlarge the picture to enough size.

Suggest to remove the limitation, if no big side effect.

[mjbvz]

This comes from the max-width of markdown on GitHub itself. We also use it so that we match Github's styling