{#- Mirrors frappe-ui docs' OnThisPage (vitepress/components/Docs/OnThisPage.vue):
a faint left rail per link, the active heading darkening its own segment.
h3s are indented only when the page also has an h2 — that's the docs' own
`'pl-7': x.type == 'h3' && h2Exists` rule. On an all-h3 page every link
stays at pl-4, which is what keeps the "On this page" label lined up with
the rail. Indenting unconditionally misaligns the label; not indenting at
all throws away the hierarchy on mixed pages. -#}
{% set has_h2 = toc_headings and (toc_headings | selectattr('level', 'equalto', 2) | list | length) > 0 %}