change text in a div css

1button {
2  visibility: hidden;
3}
4button:after {
5  content:'goodbye'; 
6  visibility: visible;
7  display: block;
8  position: absolute;
9  background-color: red;
10  padding: 5px;
11  top: 2px;
12}
13

1.pvw-title span {
2  display: none;
3}
4.pvw-title:after {
5  content: 'whatever it is you want to add';
6}

1#search {
2    width: 20em;  height: 2em;
3}

1<button>Hello</button>
2
3button {
4  background-color: green;
5  color: black;
6  padding: 5px;
7}
8