Mobile Responsive sizes and alignments are not working well and the search input border is missing

[kenn1818]

Which classes are required to be adjusted when comes to mobile responsiveness on the css level?

That is too big and some alignments are running out if come to smaller devices or screen sizes.

Besides, when comes to mobile responsive, the search input border also disappeared.

Below is the screenshot that can be previewed:

Kindly assist me on this, thanks!