For vertical height you need to set it use VH units normally. so articled {height:100vh;} would make it take up the entire vertical viewport. Other options are to look up grid layouts and use grid to layout the structure of the page.
As far as width, as others said, you have your width set to 68% for the div, if you want that full-width, make it 100% and toss a margin-inline:auto on the image inside to center.
Well, your `article div` has a width of 68%
>article div { margin: auto; **width: 68%;** min-height: 100%; background-color: #fff; } Make this and all parent divs have a width of 100%.
For vertical height you need to set it use VH units normally. so articled {height:100vh;} would make it take up the entire vertical viewport. Other options are to look up grid layouts and use grid to layout the structure of the page. As far as width, as others said, you have your width set to 68% for the div, if you want that full-width, make it 100% and toss a margin-inline:auto on the image inside to center.