rfs

RFS

About

RFS stands for Responsive Font-Size, easy to remember, easy to use. It’s a desktop-first approach which automatically calculates the correct font-size for every screen width. Desktop-first approach means you just have got to define your font-size for big screens and the font-size will automatically decrease for smaller screens. RFS is a SCSS-mixin which generates the responsive css for you.

The main advantages of using RFS

• Font-sizes will rescale for every screen width
• Super easy to use, no need to define mappings for each font-size
• Font-sizes of all text-elements will always remain in relation with each other
• Rem-based font-sizes will allow the user to change his default font-size in his browser. People with bad vision can therefore set their font-size bigger to increase readability.

What does this algorithm do?

The algorithm splits the calculation of the font-size in 2:

• 1 Static font-size for bigger screens
• 1 adaptive font-size which decreases when the screen-width of your browser decreases. This font-size is calculated in a media-query with css’ calc-function. There are some configuration variables which can influence the font-size decreasing.

The code

This input (SCSS):

.title {
  @include rfs(60);
}

Will generate this (CSS):

.title {
  font-size: 3.75rem;
}

@media (max-width: 75rem) {
  .title {
    font-size: calc(1.35rem + 3.2vw); 
  }
}

Live demo

http://codepen.io/MartijnCuppens/pen/ZBjdMy