Light Menu Problem

Hello there,

On the main page I need to use transparent menus and bright sub menus. (Both normal and sticky). But since I am using the "dark" class, the bottom menu is dark. To overcome this problem, I use '<id id = "primary-menu" class = "not-dark">'. But this time there is a difference in the appearance of the submenus. For example, border lines in between, or text and entry fields in the entry form. Which way should I follow to make the submenus look the same? (The desired sub-menu is shared in the second picture)

First Problem :
1 - https://imgur.com/CUBMEn2
2 - https://imgur.com/zMjjmIZ

Second Problem :
1 - https://imgur.com/mTW0DDy
2 - https://imgur.com/mcgVvk4

In a nutshell,

I would like me header to be transparent with white text until the user scrolls down. When the user scroll, the header background should go white and the text dark.

In addition, this link is the answer you gave to another user who asked a similar question before.

http://themes.semicolonweb.com/html/canvas/one-page/index.php

I do not want anything like this link. The design I made is not one page. I use the menu shape in the picture that I shared in my previous message that the submenus are.

I would be very happy if you could help me with this subject. Thanks in advance.