heydon, 27 days ago

Experimenting more with CSS tests. See https://heydonworks.com/article/testing-html-with-modern-css/

:has(h1):has(:is(h3,h4,h5,h6)):not(:has(h2)), :has(h2):has(:is(h4,h5,h6)):not(:has(h3)), :has(h3):has(:is(h5,h6)):not(:has(h4)), :has(h4):has(h6):not(:has(h5)) {
outline: var(--error-outline);
--error-skipped-heading-level: 'You have skipped a heading level. For example, a subsection within a section introduced by an h3 is currently introduced by an h5 or h6';
}