> <body><style>.circle{border-radius:50%;width:30vw;height:30vw;margin: auto}.br...

> <body><style>.circle{border-radius:50%;width:30vw;height:30vw;margin: auto}.breathe{animation:8s ease-in-out 0s infinite alternate breathe;}.inner{background-color:#07a;}.border{border:10px solid black;padding:10px;}@keyframes breathe{ 0%{transform:scale(1);} 25%{transform:scale(1);} 75%{transform:scale(0.25);} 100%{transform:scale(0.25);}}</style><div class="circle border"> <div class="inner circle breathe"></div></div></body>