How to code for a expandible navi? Options

[Mikazuki]

Hello! I'm kinda new to coding..and... i was wondering how or even if it's possible to make a expandable navigation menu.. like It's in a box but if you need more links in it it'll become bigger but if you want less it'll become smaller. And also for it to have a header thing at the top. >.< sorry if it doesn't make sense i'm bad at explaining..

Like.. this image I want the header in the lighter orange and links in the darker orange but it to be like expandable at the bottom so if i don't need as many links it'll become smaller.

Hope i make sense >.<

Or if it isn't possible how to code a navi like on this layout. with the headers not part of the image.