Font awesome 5 on pseudo elements

Specifying the proper font-weight seems key to have some of the symbols displayed properly (and not “□□□” instead).

font-weight has to be:

• 400 for Regular and Brands symbols
• 900 for Solid symbols
• 300 for Light symbols

I.e. if you use Font-Awesome with CSS + Webfonts, a CSS-only solution is:

@import url("font-awesome/css/fontawesome-all.min.css"); /* FA CSS import */

/* ... */

.class:before {
    /* >> Symbol you want to use: */
    content: "\f16c";
    /* >> Name of the FA free font (mandatory), e.g.:
               - 'Font Awesome 5 Free' for Regular and Solid symbols;
               - 'Font Awesome 5 Pro' for Regular and Solid symbols (Professional License);
               - 'Font Awesome 5 Brand' for Brands symbols. */
    font-family: 'Font Awesome 5 Free';
    /* >> Weight of the font (mandatory):
               - 400 for Regular and Brands symbols;
               - 900 for Solid symbols;
               - 300 for Light symbols. */
    font-weight: 900;

    /* >> Optional styling: */
    display: inline-block;
    /* ... */
}