Container Width
Core uses CSS custom properties for its main content widths. Add your overrides through Code Injection.
:root {
--container--max-width: 700px;
--container-wide--max-width: 900px;
}
Variables#
--container--max-widthcontrols the main reading column and most sections--container-wide--max-widthcontrols wide content blocks inside posts and pages
This lets you keep the default narrow reading experience while widening only selected content areas.