Create a color theme with CSS Relative Color Syntax, CSS color-mix(), and CSS color-contrast()

Fabio Giolito explores three new CSS color features that landed in Safari Technology Preview: Relative color syntax, e.g. .bg-primary-100 { background-color: hsl(from var(–theme-primary) h s 90%); } .bg-primary-200 { background-color: hsl(from var(–theme-primary) h s 80%); } .bg-primary-300 { background-color: hsl(from var(–theme-primary) h s 70%); } … CSS color-contrast, e.g. .text-contrast-primary { color: color-contrast(var(–theme-primary) vs white, …

Theming with CSS Custom Properties (CSS Variables)

Stephanie Liu has replicated the native Slack theming capabilities in the browser using CSS Variables CSS Custom Properties. The essence of the demo is actually quite simple: define the variables on the :root level, and use ‘m where needed. :root { –column-bg: #ae0001; –menu-bg-hover: #680001; –active-item: #D3A625; –active-item-text: #680001; –hover-item: #BE0002; –text-color: #FFFFFF; –active-presence: #00FFBA; …