Add a skip to content link

This makes the theme that tiny bit more accessible.

src/furo/assets/styles/_scaffold.sass

@@ -44,6 +44,22 @@ body
   color: var(--color-foreground-primary)
   background: var(--color-background-primary)
 
+.skip-to-content
+  position: fixed
+  padding: 1rem
+  border-radius: 1rem
+  left: 0.25rem
+  top: 0.25rem
+  z-index: 40
+  background: var(--color-background-primary)
+  color: var(--color-foreground-primary)
+
+  transform: translateY(-200%)
+  transition: transform 300ms ease-in-out
+
+  &:focus-within
+    transform: translateY(0%)
+
 article
   color: var(--color-content-foreground)
   background: var(--color-content-background)

src/furo/theme/furo/page.html

@@ -13,6 +13,12 @@
   <div class="visually-hidden">Hide table of contents sidebar</div>
 </label>
 
+<a class="skip-to-content muted-link" href="#furo-main-content">
+  {%- trans -%}
+  Skip to content
+  {%- endtrans -%}
+</a>
+
 {% if theme_announcement -%}
 <div class="announcement">
   <aside class="announcement-content">
@@ -87,7 +93,7 @@
             <i class="icon"><svg><use href="#svg-toc"></use></svg></i>
           </label>
         </div>
-        <article role="main">
+        <article role="main" id="furo-main-content">
           {% block content %}{{ body }}{% endblock %}
         </article>
       </div>