grid-responsive.css

/*
*   @title  Responsive grid columns
*/

/* Equal size grid items */
.el {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(min(300px, 100%), 1fr));
    gap: 20px;
}

/* Alternative if you want grid items to be different sizes */
.el {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, auto));
    gap: 20px;
}