Resolve CSS color variables
Resolve a color custom property from an explicit context map or use its declared fallback.
var(--alias, #111827)--alias: var(--brand)
--brand: #806eae#806eaevar(--missing, #334155)--missing: absent#334155Follow an alias or use its fallback
Without a value or fallback, non-strict resolution retains var(--missing).
Resolve from an explicit context map
PHPColor follows resolvable aliases until it reaches a concrete color. When the requested key is absent, it resolves the declared fallback instead.
<?php
use PhpColor\Color\Css\CssColor;
use PhpColor\Color\Css\CssContext;
$context = CssContext::light([
'--brand' => '#806eae',
'--alias' => 'var(--brand)',
]);
$alias = CssColor::var('--alias', '#111827');
$fallback = CssColor::var('--missing', '#334155');
echo CssColor::resolve($alias, $context)->toHex(); // #806eae
echo CssColor::resolve($fallback, $context)->toHex(); // #334155A context map is not the cascade
PHPColor resolves only the custom-property values supplied by the application. It does not discover declarations or calculate which declaration wins.
Variable keys include their leading --. Invalid values fail when PHPColor attempts to parse them.
Missing variables without fallbacks remain deferred in non-strict mode and throw InvalidColorException in strict mode.
PHPColor does not parse arbitrary token streams, stylesheets, selectors, or inheritance.