The code for a horizontal line is tags can become very tedious, and will not allow you to adjust the space between lines. Instead you can use CSS, which is a more advanced form of HTML.

When creating an HTML page, the equivalent of leading is the CSS "line-height" property, used to set the amount of space between each line. The line-height can be set to a fixed height ...

CSS isn't necessary for ... adding some extra spacing, or using a different font. But you should layer this styling on top of clean, robust HTML to provide the best foundation possible.

jsFiddle is the perfect solution; it provides a custom environment (based on user selections) to test (or fiddle with) your JavaScript, HTML, and CSS code ... page includes a line of buttons ...