how mto change the label font style in css

1.swap {
2  position: relative;
3  padding-left: 80px;
4}
5.swap + .swap {
6  margin-top: 5px;
7}
8.swap label {
9  position: absolute;
10  left: 0;
11}
12
13input:focus+label {
14  font-family: 'Roboto Medium', sans-serif;
15  font-size: 16px;
16  color: #000;
17  font-weight: 100;
18}