css-grid practice

first one

grid-template-columns, grid-template-rows

                    
.grid-1 .container {
    display: grid;
    grid-template-columns: 100px auto;
    grid-template-rows: 100px 100px 200px;
    grid-gap: 3px;
}
100px width fixed / 100px height fixed
auto width / 100px height fixed
100px width fixed / 100px height fixed
auto width / 100px height fixed
100px width fixed / 200px height fixed
auto width / 200px height fixed

third one

grid-auto-flow: dense;