State ( hover, focus, visited, active)

button:active {
      background-color: tomato;
    }
    button:hover {
      background-color: yellow;
    }
    input:focus {
      background-color: green;
    
    }
    a{
      border-radius: 10px;
      padding:5px;
      background-color: yellowgreen;
    }
    a:visited {
      color: tomato;
    }
    a:hover {
      color: violet;
    }
    a:hover {
      color: blue;
    }
    form{
      border: 1px solid salmon;
      display:flex;
      flex-direction:column;
      padding:20px;
    }
    form:focus-within{
      border-color:seagreen;
    }
    form:hover input:focus{
      border-color:yellowgreen;
    }