No skip to content link

[jmankoff]

A best practice for accessibility is to have a skip to content link at the beginning of every web page that is invisible and skips to content, something like this:

<a class="skip-main" href="#quarto-document-content">Skip to main content</a>

It's typically styled something like this:

a.skip-main {
    left:-999px;
    position:absolute;
    top:auto;
    width:1px;
    height:1px;
    overflow:hidden;
    z-index:-999;
}
a.skip-main:focus, a.skip-main:active {
    left: auto;
    top: auto;
    width: 30%;
    height: auto;
    overflow:auto;
    margin: 10px 35%;
    padding:5px;
    text-align:center;
    font-size:1.2em;
    z-index:999;
}

I've found a work around using
announcement:
content: Skip to main content
position: above-navbar
dismissable: false

However (1) this creates a non-zero height announcement area above the navbar and (2) this precludes announcements being used for anything else. Quarto should have the skip-to-content link by default built into all websites to improve their WCAG compliance.

[mcanouil]

Duplicate of #10096