Features

TrapCSS supports all CSS selectors.

• Supported selectors

  Common	Attribute	Positional	Positional (of-type)	Other
  * - universal <tag> - tag # - id . - class   - descendant > - child + - adjacent sibling ~ - general sibling	[attr] [attr=val] [attr*=val] [attr^=val] [attr$=val] [attr~=val]	:first-child :last-child :only-child :nth-child() :nth-last-child()	:first-of-type :last-of-type :only-of-type :nth-of-type() :nth-last-of-type()	:not()

• Retention of all transient pseudo-class and pseudo-element selectors which cannot be deterministically checked from the parsed HTML.

• Removal of unused @font-face and @keyframes blocks.

• Removal of unused CSS variables.

• Deep resolution of composite CSS variables, e.g:

  :root {
    --font-style: italic;
    --font-weight: bold;
    --line-height: var(--height)em;
    --font-family: 'Open Sans';
    --font: var(--font-style) var(--font-weight) 1em/var(--line-height) var(--font-family);
    --height: 1.6;
  }
  
  @font-face {
    font-family: var(--font-family);
    src: url("/fonts/OpenSans-Regular-webfont.woff2") format("woff2"),
         url("/fonts/OpenSans-Regular-webfont.woff") format("woff");
  }
  
  body {
    font: var(--font);
  }