href="//cdnjs.cloudflare.com/ajax/libs/semantic-ui/2.2.12/semantic.min.css" code example

Example 1: semantic-ui cdn

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/semantic-ui/2.4.1/semantic.min.css">

Example 2: cdnjs smeantic ui

//add this to your index.html file, inside head tag 
<link
      rel="stylesheet"
      href="https://cdnjs.cloudflare.com/ajax/libs/semantic-ui/2.4.1/semantic.min.css"
    />