CSS

how to make background more darker with css

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

How do I make my background color darker in CSS

body {
    display: grid;
    place-items: center;
    height: 100vh;
}
div {
    width: 50vw;
    height: 50vh;
    background: linear-gradient(to bottom right, #55566a, #282834);
    border-radius: 10px;
}