Creating a Sticky Footer with Flexbox

Flexbox is now supported by almost all modern browsers. For specific info, check the caniuse.com page.

As you can see in the code below, only the site-content wrapper and the content itself are styled to make this work. You can style the footer as you like.
[css].content-wrapper
{
display: flex;
min-height: 100vh;
flex-direction: column;
}
.content-wrapper .content
{
flex: 1;
}
.content-wrapper .footer{}[/css]

If your content is directly within the body tag you could use the style of .content-wrapper on the body instead.