How to make the post layout width not apply to the post navigation at the bottom

Hi there,

try adding this CSS:

.single-post .paging-navigation {
    margin-left: calc(-100vw / 2 + 100% / 2);
    margin-right: calc(-100vw / 2 + 100% / 2);
    max-width: 100vw;
    width: auto;
}

Then edit the Navigation Block Element, select the parent Container Block, and adjust the Inner Container Width to suit. I would suggest also giving it some left and right padding to stop it from touching the screen edges on smaller devices.

Hi, can I ask an unrelated question? To be able to customize the site as you like, I had to add a lot of custom css code, like this site of mine is adding 5 custom codes. Does adding so much custom code affect site speed?

CSS only becomes a problem if you start adding hundreds/thousands lines of CSS. A couple of hundred lines of CSS is not going to make any difference to performance.