Today I Learned

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Max out your `vw` with Sass

A pretty big downside to vw units is that they are relative to the viewport width, regardless of the maximum width of your site itself. So if the user fullscreens your site on a big monitor, your vws will be huge while the rest of your site stops growing at some reasonable width. Here’s a handy Sass mixin to address that problem.

@mixin max-vw($attr, $value) {
  #{$attr}: #{$value}vw;
  @media screen and (min-width: 1400px) {
    #{$attr}: ($value/100) * 1400px;

Basically, since 1 vw is 1% of the viewport width, at a certain max breakpoint, we use an equivalent percentage of the max site width instead.

For example, this will assign a font-size of 10vw, but after the viewport enlarges past 1400px, the font-size will then set to a static 140px (10% of 1400px):

.foo {
  @include max-vw(font-size, 10)