I agree! While at first I thought this feature applied to the browser main navigation bar, I realized it only applied to the menu bar.
A customizable main bar would be far more useful. Samsung, Soul, Berry and Whale all offer fully customizable nav bars.
It would be great to have a feature added to the settings area so we could have a different background image available instead of just a single colored background. I have my start page setup with various speed dials so I can select a saved bookmark and go to that page quickly.
I thought I'd solved it, but now, after installing the latest Vivaldi on my phone, I changed 2 web pages and changed their css files.
Now I'm stuck with the same problem: I cannot clear the cache in Vivaldi and the pages display wrongly!
The first 2 instructions in the link above, from 2020, say:
Tap the site icon (lock for secure site)
Tap Site Settings
I can do 1. , but 2. is not available in this version of Vivaldi, the latest available on the Vivaldi webpage.
The pages with altered css display correctly in Firefox and UC, a Chinese browser.
