检查MDN以了解如何使用text-shadow。
语法是offset-x | offset-y | blur-radius | color:
.icon-red {
color: #c00000;
text-shadow: 0 0 10px blue;
}Run Code Online (Sandbox Code Playgroud)
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.0.13/css/all.css" integrity="sha384-DNOHZ68U8hZfKXOrtjWvjxusGo9WQnrNx2sqG0tfsghAvtVlRW3tvkXWZh58N9jp" crossorigin="anonymous">
<i class="fas fa-3x fa-heart icon-red"></i>Run Code Online (Sandbox Code Playgroud)