// 右上角  github链接  
.github-corner:hover .octo-arm{
      animation:octocat-wave 560ms ease-in-out
      }
 @keyframes octocat-wave{
      0%,100%{
        transform:rotate(0)}20%,60%{transform:rotate(-25deg)
        }
      40%,80%{
        transform:rotate(10deg)
        }
 }
 @media (max-width:500px){
      .github-corner:hover .octo-arm{animation:none}
      .github-corner .octo-arm{animation:octocat-wave 560ms ease-in-out}
}