How to underline link with different color than text?

css underline style text

Heads up! Currently text-decoration-color is widely supported, so not need for tricks like described below

By CSS definition the link, or any other text in HTML element can have text-decoration property one of following values:

  • underline
  • overline
  • line-through

There are more options, however as of 3rd quarter of 2018 these have partial support in browsers. Not to mention text-decoration-color which would allow us to make underline with different color than link text. So to to make it work properly on all browsers, we need to make some workaround for underline.

The first idea You might come with is to use CSS border at bottom. While it will make underline, the line itself will have large offset from text.

Using box-shadow

It turned out, that the best results close to the proper text-decoration-color can be achieved with box-shadow. The idea is tu put thin shadow without spread under text. The results are fine, except that there are no slight cutouts around glyph parts, which are over shadow. Also on block elements, it will be placed under whole block, not only text:


So to overcome this we need to have our links to have display of either inline or inline-block:


Example CSS rule:

    box-shadow: 0 -0.1em 0 inset red;

Please note that shadow will not scale with text if value is in pixels, that's why em unit was used, so that when font size will change, the shadow thickness will also change.