[NSFW] Gutenberg editing pages can’t fully pre-empt the entire page

The area in the Gutenberg editor that displays the block is only part of the center, with large margins on the left and right sides, which leads to the fact that when I set the height of the container higher, and add an image to the container, half of the image doesn’t show up in the editor any more, which prevents me from seeing the effect of the adjustment in real time. Where can I adjust this please.