Cascading StyleSheets (CSS) is used by software to change the style of the document. Such as colors, layout, and size of text.
Snippet
<style>h1{
color: blue;
}
</style>
Add the above snippet to your first.html page. Remember, where does pre-loaded CSS go? For more reading on the abilities of CSS, please check the below reference. Each browser recognizes CSS a little differently - so not all selectors or styling commands will work.