Here is a list of the color codes in the ColorPalette, and the sections of this ~TiddlyWiki that they affect. Please note that authors of other ~TiddlyWikis may have configured theirs differently in the StyleSheet. But experimenting with these will give you practice so that you can more easily reconfigure the colors of any ~TiddlyWiki.
Background: This controls the color of the background or 'paper', and the text in the title and subtitle.
Foreground: This controls the color of the text.
~PrimaryPale: This controls the color of the Interface Options box.
~PrimaryLight: This controls the color of the top of the Header gradient.
~PrimaryMid: This controls the color of the text in the ~MainMenu, the color of the text for links, the color of the text in the lists of tiddlers and tags, and the color of the bottom of the Header gradient.
~PrimaryDark: This controls the color of the text of the items in the top of the right hand menu and the text of the buttons on the tiddlers.
~SecondaryPale: This controls the color of the background of the boxes in those tiddlers that show snippets of the ~TiddlyWiki code.
~SecondaryLight: This controls the color that appears when the tiddler buttons or items in the right hand menu are highlighted.
~SecondaryMid: This controls the color of the title cells in tables, that is, cells which begin with an exclamation mark (!). It also controls the color of the box that appears when changes have been saved, and the color of the tiddler buttons when they are selected.
~SecondaryDark: This controls the color of the titles of the tiddlers.
~TertiaryPale: This controls the color of the right hand menu that shows lists of tags and tiddlers, as well as the color of the tag button on the tiddlers.
~TertiaryLight: This controls the color of the borders around the right hand menus.
~TertiaryMid: This controls the color of the unselected tabs behind the list of tags and tiddlers in the bottom right hand menu.
~TertiaryDark: This controls the color of the subtitle of each tiddler, that is, the author of the tiddler, the most recent date it was modified and date it was created.
http://flatuicolors.com/#