how to make background more darker with css

1/* makes your image darker */
2background-image: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)), 
3url(your image location)

1body {
2    display: grid;
3    place-items: center;
4    height: 100vh;
5}
6div {
7    width: 50vw;
8    height: 50vh;
9    background: linear-gradient(to bottom right, #55566a, #282834);
10    border-radius: 10px;
11}