<!DOCTYPE html>
<title>CSS Anchor Positioning Test: @position-try and cascade interaction</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#fallback-apply">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
.cb {
position: relative;
width: 100px;
height: 100px;
background: lightpink;
display: inline-block;
}
.abs {
position: absolute;
background: darkcyan;
left: 0px;
top: 0px;
width: 150px; /* force fallback */
height: 25px;
position-try-fallbacks: --pf;
}
@position-try --pf {
width: 50px;
left: 50px;
top: 50px;
}
</style>
<!-- Basic @position-try rule -->
<div class=cb>
<div id=abs_try class=abs></div>
</div>
<script>
test(() => {
assert_equals(abs_try.offsetLeft, 50);
assert_equals(abs_try.offsetTop, 50);
}, '@position-try rule applies');
</script>
<!-- Inline style -->
<div class=cb>
<div id=abs_inline class=abs style="left:20px"></div>
</div>
<script>
test(() => {
assert_equals(abs_inline.offsetLeft, 50);
assert_equals(abs_inline.offsetTop, 50);
}, '@position-try rule wins over inline style');
</script>
<!-- !important -->
<style>
#abs_important {
left: 10px !important;
}
</style>
<div class=cb>
<div id=abs_important class=abs></div>
</div>
<script>
test(() => {
assert_equals(abs_important.offsetLeft, 10);
assert_equals(abs_important.offsetTop, 50);
}, '@position-try rule does not win over !important');
</script>
<!-- Animations -->
<style>
@keyframes anim {
from { top: 20px; }
to { top: 20px; }
}
#abs_animation {
animation: anim 1000s steps(2, start) paused;
}
</style>
<div class=cb>
<div id=abs_animation class=abs></div>
</div>
<script>
test(() => {
assert_equals(abs_animation.offsetLeft, 50);
assert_equals(abs_animation.offsetTop, 20);
}, '@position-try rule does not win over animations');
</script>
<!-- Transitions -->
<style>
#abs_transition.move {
top: 10px !important;
transition: top 1000s steps(2, start);
</style>
<div class=cb>
<div id=abs_transition class=abs></div>
</div>
<script>
test(() => {
abs_transition.offsetTop;
abs_transition.classList.add('move');
assert_equals(abs_transition.offsetLeft, 50);
assert_equals(abs_transition.offsetTop, 30);
}, '@position-try rule does not win over transitions');
</script>
<!-- revert / revert-layer -->
<style>
#abs_revert {
position-try-fallbacks: --pf-revert;
}
@layer author-layer {
#abs_revert {
top: 30px;
left: 30px;
}
}
#abs_revert {
top: 20px;
left: 20px;
/* overflowing .cb to force --pf-revert to be applied */
width: 200px;
height: 200px;
}
@position-try --pf-revert {
left: revert;
top: revert-layer;
width: 30px;
height: 30px;
}
</style>
<div class=cb class=abs>
<div id=abs_revert class=abs></div>
</div>
<script>
test(() => {
assert_equals(abs_revert.offsetLeft, 0, "left reverted back to user origin");
assert_equals(abs_revert.offsetTop, 20, "top reverted back to author");
assert_equals(abs_revert.offsetWidth, 30, "width from --pf-revert");
assert_equals(abs_revert.offsetHeight, 30, "height from --pf-revert");
}, '@position-try revert / revert-layer reverts to user / author origin');
</script>
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