The :is Selector

I imagine a lot of us have had to write some gnarly CSS like this in the past:

.post h1,
.post h2,
.post h3 {
    line-height: 1.2;
}

.post img,
.post video {
    width: 100%;
}

Thankfully, CSS has got our back again with the :is pseudo-class.

That CSS can now be hugely simplified into this instead:

.post :is(h1, h2, h3) {
    line-height: 1.2;
}

.post :is(img, video) {
    width: 100%;
}

When things get more complex, it gets even more useful, because you can chain other selectors, such as :not and :first-child.

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