how to position a footer

1#page-container {
2  position: relative;
3  min-height: 100vh;
4}
5
6#content-wrap {
7  padding-bottom: 2.5rem;    /* Footer height */
8}
9
10#footer {
11  position: absolute;
12  bottom: 0;
13  width: 100%;
14  height: 2.5rem;            /* Footer height */
15}