Adhere to Material 3.

[RokeJulianLockhart]

Rationale

Currently, the GUI design philosophy is definitely Material 2, with iconography that looks like it's from Material 1 (the AOSP V5 days).

Examples

Some examples are:

1. Filled (instead of outlined) iconography:

   

2. Coloured headings that lack shadow when scrolled, and

3. Toggles with a non-pill outline:

   

Disclaimer

This isn't a request for Monet / You, like #1080 (comment) and #1075 (comment) request. Those request user-modifiable colour scheme support, not a modification to the application style (if you're familiar with Qt, hopefully that terminology adequately elaborates).

Environment

Application	f-droid.org/repo/ws.xsoh.etar_48.apk
OS	OEM distribution of AOSP 14

[corydalis10]

I'd love to be a part of this issue!