Answers for "width 100% not working in css grid"

css grid not taking full row height

.img_container{
    height: 50%; // or whatever value just make sure you give your parent a height
    width: 100%;
    background: url('link to your image') 50% no-repeat;
    background-size: cover;
 }

css grid not working

<!-- The first thing is to make sure that you have; -->
display = grid;

<!-- if it doesnt work, check the link below. Its
 better tha some random stuff online-->