Browsers are changing their default <h1> styles, so a <h1> will no longer adapt its style based on surrounding sectioning elements like <section>, <article>, <nav>, and <aside>.

This page uses default user agent styles so you can quickly test the appearance of h1s in sectioning elements. If all of the following headers are the same size, then your browser is using newer UA styles:

Level 1

For more information, see Default styles for h1 elements are changing.