[UI] Active in-page navigation link never bolds: `font-weight: 5000` is an invalid CSS value

Description

Five stylesheets set font-weight: 5000 on the .active state of an in-page ("on this page") navigation link. font-weight accepts numeric values in the range 1–1000; 5000 is out of range, so the declaration is invalid and the browser drops it. The active-section highlight therefore never renders bold.

Affected locations:

In the two intra-page.js files the effect is worse than a missing bold. The rule reads:

.list {
  color: #000000;
}
.active {
  font-weight: 5000;   /* invalid, dropped */
  color: #000000;      /* identical to .list */
}

Because the weight is dropped and the colour matches the inactive state, .active produces no visual change at all — there is no indication of which section the reader is currently on.

Pages affected include the Sistent documentation pages (e.g. https://layer5.io/projects/sistent/components/table), the Handbook, the legal pages, and Adventures of Five.

Expected Behavior

The active entry in the in-page navigation should be visually distinct from the inactive entries — a valid weight such as font-weight: 700 (or bold), and in the intra-page.js cases an .active colour that actually differs from .list.

Worth noting while fixing: both intra-page.js files hardcode color: #000000 rather than using a theme token, so these links are near-invisible in dark mode. Switching to props.theme.* would address the active state and dark mode together, matching how sistent.style.js already does it.

Screenshots

N/A — reproducible by inspecting any .active in-page nav link in devtools; the font-weight declaration shows as invalid/struck-through.

Environment:

• Host OS: any
• Browser: any

Start with the five affected files and inspect each .active rule, especially the two intra-page.js components and their theme usage. Verify the active entry has a valid font weight and a visual difference from inactive entries, including in dark mode, then inspect the listed affected pages in the browser to confirm the current-section link is visibly distinct.