For the upcoming CP-project tasks, we would like to have a possibility to choose between few different "accessibility-schemes".

The idea would be to have few buttons inside a task, each of which would have some pre-defined set of properties combined.
For example:
Button "Scheme 1" would change following properties:

• Background = darkGray
• Text color = yellow

whereas button "Scheme 2" would use another set of properties:

• Background = yellow
• Text color = black

and for example "Reset" -button would restore all properties to the default values.

Naturally, all of the schemes should be freely defined and they should remain as defined throughout the entire task.

Also, similar type of possibility, but for changing font size would be nice.
For example:
we would have a button showing throughout the task with a "+"sign, which would increase the font-size used in all of the labels by some increment per each click. And also ""-sign, which would decrease by same increment per click.
Additional value would be if the increment would be freely defined (1/2/5 pixels? or what ever is the unit we are using).