Horizontal rule/line beneath each

Question

I am trying to place a 100% horizontal line (rule) automatically beneath every instance of an

header tag using CSS.

Example

Answer 1

If you are feeling something is going wrong, you can use zoom: 1;. See this fiddle

(I have removed span but you can set class to your h1 tag.)

CSS

h1 {
    font-family: Calibri, "Helvetica", san-serif;
    line-height: 1.5em;
    color: black;
    font-size: 20px;
    border-bottom: 2px solid red;
    zoom: 1;
}

HTML...

Introduction