PostCSS plugin inserts an empty content block into your :before and :after pseudo elements if it is missing.
Shout-out to omgovich with his postcss plugin, for inspiration and guidance.
.foo:after {
content: '';
display: block;
}
.foo:before {
display: inline-block;
}
.foo:after {
content: '';
display: block;
}
.foo:before {
display: inline-block;
content: '';
}
postcss([ require('postcss-pseudo-content-insert') ])
See PostCSS docs for examples for your environment.