The following code generator outputs a web font embed code, which allows you to declare font-family once, and to use font-weight and font-style to switch between different weights.

body {
  font-family: "Open Sans", sans-serif;
}
/* headings and other bold text will use 
   the bold weight of our custom font */

This is opposed to the default Font Squirell method of applying different font-familys to each actual weight, whilst the weight and the style of all weights is set to “normal”.

body {
  font-family: "Open Sans Regular", sans-serif;
}
h1 {
  font-family: "Open Sans Bold", sans-serif;
  font-weight: normal; /* prevent faux-bold */
}