Have a look at this pretty gradient effect. The underline expands and fills up the text on hover, it will look great for links on your next website, it will work on links that span multiple lines too. It was designed by Will King.
If you are having trouble with the pen, try the archived copy on GitHub
Hover Effect on Multiple Lines Snippet
See the Pen How do I get a custom colored underline that will span multiple lines? by Will King (@Wking) on CodePen.0