sousa-gecko/testing/web-platform/tests/css/css-mixins/functions/function-layer.html

<!DOCTYPE html>
<title>Custom Functions: @function within @layer</title>
<link rel="help" href="https://drafts.csswg.org/css-mixins-1/#conditional-rules">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../resources/utils.js"></script>

<div id=target></div>
<div id=main></div>

<!-- To pass, a test must produce matching computed values for --actual and
     --expected on #target. -->

<template data-name="Single function within anonymous layer">
  <style>
    @layer {
      @function --f() { result: 1px; }
    }
    #target {
      --actual: --f();
      --expected: 1px;
    }
  </style>
</template>

<template data-name="Last anonymous layer wins">
  <style>
    @layer {
      @function --f() { result: 1px; }
    }
    @layer {
      @function --f() { result: 2px; }
    }
    #target {
      --actual: --f();
      --expected: 2px;
    }
  </style>
</template>

<template data-name="Unlayered styles win">
  <style>
    @layer {
      @function --f() { result: 1px; }
    }
    @layer {
      @function --f() { result: 2px; }
    }
    @function --f() { result: 3px; }
    #target {
      --actual: --f();
      --expected: 3px;
    }
  </style>
</template>

<template data-name="Unlayered styles win, reverse">
  <style>
    @function --f() { result: 3px; }
    @layer {
      @function --f() { result: 1px; }
    }
    @layer {
      @function --f() { result: 2px; }
    }
    #target {
      --actual: --f();
      --expected: 3px;
    }
  </style>
</template>

<template data-name="Single named layer">
  <style>
    @layer base {
      @function --f() { result: 10px; }
    }
    #target {
      --actual: --f();
      --expected: 10px;
    }
  </style>
</template>

<template data-name="Named layers">
  <style>
    @layer base {
      @function --f() { result: 10px; }
    }
    @layer theme {
      @function --f() { result: 20px; }
    }
    #target {
      --actual: --f();
      --expected: 20px;
    }
  </style>
</template>

<template data-name="Named layers, reordered">
  <style>
    @layer theme, base;

    @layer base {
      @function --f() { result: 10px; } /* Winner */
    }
    @layer theme {
      @function --f() { result: 20px; }
    }
    #target {
      --actual: --f();
      --expected: 10px;
    }
  </style>
</template>

<script>
  test_all_templates();
</script>