action在css中的用法

element:action {  style-property: value;}

button:hover {  background-color: #00FF00;}

a:active {  border: 1px solid #FF0000;}

h1:hover {  font-size: 1.5em;  font-weight: bold;}

.hidden:hover {  display: block;}

.my-element:active {  animation: my-animation 2s infinite;}