Change the color of the Underline

Hello guys,

I install your plugin and is awesome, however, iw as wondering if you could help me.

I would like to change the color of the underline, to not be the same as the color of the letters. Is that possible with CSS?

I’m not an expert, and i have been trying for hours!!!
https://miotaku.com/lista-top-mejores-animes-comedia-romantica-de-siempre/

As you can see the second paragraph, the letters are kinda blue, but the underline still white. I would like to change it to that blue too.

For the blue one i use this:
.blog strong { color: #19709E!important; }
.single-post strong { color: #19709E!important; }

.blog hover{ color: #19709E!important; }
.single-post hover{ color: #19709E!important; }

But for the underline i dont know :/

Thanks in advance.