This filter not work in brave adblock-rust but in ublock work

Hi, I apologize in advance if I opened an issue incorrectly, but I wanted to point out that your adblock doesn't work with this rule
`www.startpage.com##div:matches-css(background:/rgb\(247,\s*247,\s*255\)/):has(button[type="button"]:has-text("/Allow Startpage ads/i")):remove()`
to block these annoying messages:

and this message at the bottom of the page.

I personally wrote the filter by hand with Ublock Origin that I installed in Brave Origin but when importing the filter into brave ablock-rust the rule doesn't work and I can't understand why, furthermore I haven't found an official wiki with filter syntax for your adblock-rust.

One last thing, how can I enable the two sliders like Ublock Origin in brave adblock-rust which allow me to dose the selection of elements so comfortably because the popup I see of your adblock is really basic and almost useless I would say.

Start by reproducing the provided Startpage filter in Brave adblock-rust and compare its behavior with uBlock Origin. Identify which parts of the rule or requested element-selection controls are unsupported, then document or address the discrepancy so the reported messages are handled as intended.

Written by the indexing model from the issue text.