Super Dim UI
Super Dim UI is a simple resource pack that makes most GUIs in Minecraft darker. It also changes some things to be purple instead of green such as sliders and buttons.
This pack was made in 1.17.40 but should work in most Bedrock Edition versions
Looking for the Java Edition Version? You can find it here!
Super Dim UI now has 8 recolours for both Bedrock and Java editions! All the recolours are included as one pack on Bedrock so you dont have to worry about downloading multiple files.