.does-nothing-button:focus{-webkit-animation:rainbow 2s ease-in-out infinite;animation:rainbow 2s ease-in-out infinite;background:linear-gradient(45deg, red, orange, yellow, green, blue, indigo, violet);background-size:1000% 1000%}.does-nothing-button:focus:after{content:"... just kidding!"}@keyframes rainbow{0%{background-position:0% 80%}25%{background-position:50% 50%}50%{background-position:100% 20%}75%{background-position:50% 50%}100%{background-position:0% 80%}}