How to Change Link Underline Color with CSS

Last night, when I look at Basecamp website, I notice an interesting CSS stuff.

When I hover the Nav link at the header, there will be a nice yellow highlight appear below the link. This is cool, tho .

When I inspect the a tag, they used text-decoration stuff.

I do a quick research and found this awesome, simple CSS magic to change the underline color.

I already do the research, you just need to grab the popcorn 🍿 and enjoy the journey 🚀.

By default, the color of the underline is set the same as the text color of the link. If the link is blue 🟦, the underline also a blue color 🟦. But, you know right, because of human's creativity(cough, cough...)😆, sometimes we want to give the underline a different color from the text of the link.

There are two ways I found to make this happen. One is using the text-decoration stuff, the second one is using the old border-bottom trick.

personally, I prefer text-decoration over border-bottom. The right tool for the right job. I donno.

✅ `text-decoration`

text-decoration is the most straightforward way to underline text.

`text-decoration-color` is what we needed

a {
    text-decoration: none;
    color: blue;
}

/* show underline on hover */
a:hover {
    text-decoration: underline;
    text-decoration-color: red;
    -webkit-text-decoration-color: red;
}

note: -webkit is for Safari.

This is the only thing you needed. If you want to customize more, read more :P

🌈 `text-decoration` properties

text-decoration works fine by itself, but you can add a few properties to customize the way it looks:

1) `text-decoration-color`

text-decoration-color lets you change an underline’s color separately from its text color.

2- `text-decoration-skip`

This property will skip the edgy alphabet like g, p, f. It didn't go through it. Examples :

3- `text-decoration-style`

text-decoration-style give you a free underline design using different values. No need to add SVG.

Here are the available values that you can use:

dashed
dotted
double
solid
wavy

note: This example is from Mozilla MDN. You also can seperate the text-decoration into text-decoration-color and text-decoration-style.

a {
 text-decoration: underline;
 text-decoration-color: red;
 text-decoration-style: wavy;
}

4- `text-underline-offset`

This is quite cool. It can be used to define how far the line is from the initial text.

5- `text-underline-thickness`

This property is used to tell how big the underline is.

✅ `border-bottom`

disclaimer: if you happy with the first trick, just go with it. This is just another same trick.

If we want to use border-bottom trick, first we need to remove the underline with the text-decoration property value of none. Then we add the border-bottom property with 3 short-hand CSS values of 3px solid red.

3px = Variable of the underline width in pixels

solid = Border style (solid, dotted, or dashed)

red = Color code. Hex also can, like #999999