XF 1.4 Increase default font size Message Body -Help with Style Property

[rbharathi]

Hi ,
I want to increase the default font size for post content,(message content),
I tried by editing style properties,
there are so much to choose with,
I think, i am doing something wrong, so changes are not reflected,

i am trying in these sections


Message List
Message Container
User Info Container
User Info Block
Avatar Holder
User Text Block
Extra User Info
Content Container
Main Content
Controls Area
Notices
Likes


Also i want to change the background color of, category ribbon
there are so much css styling i cant find the right one,
only i need to change these two things,
someone tell the correct property please.

 

[Amaury]

Style Properties > Message Elements > Message Text

Style Properties > Building Blocks > Sub-Heading

 

[rbharathi]

Style Properties > Message Elements > Message Text

Style Properties > Building Blocks > Sub-Heading

Thank you very much @Maru