首頁 > web前端 > css教學 > 定制財產腦扭曲

定制財產腦扭曲

尊渡假赌尊渡假赌尊渡假赌
發布: 2025-03-22 09:33:25
原創
216 人瀏覽過

Custom Property Brain Twisters

I am part of that 82% that got it wrong in Lea’s quiz (tweet version).

Here’s the code:

:root {
  --accent-color: skyblue;
}

div {
  --accent-color: revert; 
  background: var(--accent-color, orange);
}
登入後複製

So what background do I expect

to have?

My brain goes like this:

  1. Well, --accent-color is declared, so it’s definitely not orange (the fallback).
  2. The value for the background is revert, so it’s essentially background: revert;
  3. The background property doesn’t inherit though, and even if you force it to, it would inherit from the , not the root.
  4. So… transparent.

Nope.

Lea:

[Because the value is revert it] cancels out any author styles, and resets back to whatever value the property would have from the user stylesheet and UA stylesheet. Assuming there is no--accent-colordeclaration in the user stylesheet, and of course UA stylesheets don’t set custom properties, then that means the property doesn’t have a value.

Since custom properties are inherited properties (unless they areregisteredwithinherits:false, but this one is not), this means the inherited value trickles in, which is — you guessed it —skyblue.

Stephen posted a similar quiz the other day:

Again, my brain does it totally wrong. It goes:

  1. OK, well, --color is declared, so it’s not blue (the fallback).
  2. It’s not red because the second declaration will override that one.
  3. So, it’s essentially like p { color: inherit; }.
  4. The

    will inherit yellow from the , which it would have done naturally anyway, but whatever, it’s still yellow.

Nope.

Apparently inherit there is actually inheriting from the next place up the tree that sets it, which html does, so green. That actually is how normal inheriting works. It’s just a brain twister because it’s easy to conflate color the property with --color the custom property.

It also might be useful to know that when you actually declare a custom property with @property you can say whether you want it to inherit or not. So that would change the game with these brain twisters!

@property --property-name {
  syntax: '<color>';
  inherits: false;
  initial-value: #c0ffee;
}
登入後複製

以上是定制財產腦扭曲的詳細內容。更多資訊請關注PHP中文網其他相關文章!

本網站聲明
本文內容由網友自願投稿,版權歸原作者所有。本站不承擔相應的法律責任。如發現涉嫌抄襲或侵權的內容,請聯絡admin@php.cn
最新問題
熱門教學
更多>
最新下載
更多>
網站特效
網站源碼
網站素材
前端模板