three.js/build/templates/repobanner.template

<style>
#forkongithub a {
    background: #000;
    color: #fff;
    text-decoration: none;
    font-family: arial,sans-serif;
    text-align: center;
    font-weight: bold;
    padding: 5px 40px;
    font-size: 0.9rem;
    line-height: 2rem;
    position: relative;
    transition: 0.5s;
    display: block;
    width: 300px;
    position: absolute;
    top: 0;
    right: 0;
    transform: translateX(150px) rotate(45deg) translate(10px,70px);
    box-shadow: 4px 4px 10px rgba(0,0,0,0.8);
    pointer-events: auto;
}
#forkongithub a:hover {
    background: #c11;
    color: #fff;
}
#forkongithub a::before,#forkongithub a::after {
    content: "";
    width: 100%;
    display: block;
    position: absolute;
    top: 1px;
    left: 0;
    height: 1px;
    background: #fff;
}
#forkongithub a::after {
    bottom: 1px;
    top: auto;
}

#forkongithub{
    z-index: 9999;
    /* needed for firefox */
    overflow: hidden;
    width: 300px;
    height: 300px;
    position: absolute;
    right: 0;
    top: 0;
    pointer-events: none;
}
#forkongithub svg{
  width: 1em;
  height: 1em;
  vertical-align: middle;
}
@media (max-width: 900px) {
    #forkongithub a{
        line-height: 1.2rem;
    }
}
@media (max-width: 700px) {
  #forkongithub {
    display: none;
  }
}
@media (max-width: 410px) {
    #forkongithub a{
        font-size: 0.7rem;
        transform: translateX(150px) rotate(45deg) translate(20px,40px);
    }
}

</style>
<div id="forkongithub"><a href="https://github.com/gfxfundamentals/threejsfundamentals">Fix, Fork, Contribute {{{include "build/templates/octocat-icon.svg"}}}</a></div>