> I am working in a notebook. I would like to be able to easily style and restyle code fragments in a text cell.

 1. Create a new notebook
 2. Go to Format -> Edit Stylesheet...
 3. In the text field at the top of the style window, enter InlineCode and press Enter. This creates the `InlineCode` style, and inserts a corresponding cell below.
 4. Select the InlineCode cell in the style window and press Command-Shift-E to reveal its cell expression.  It will be

        Cell[StyleData["InlineCode"],
         MenuSortingValue->10000]

    Edit it to add styling, e.g.

        Cell[StyleData["InlineCode"],
         FontFamily -> "Consolas",
         FontColor -> RGBColor[0.2, 0.4, 0.8],
         MenuSortingValue->10000]

    Press Command-Shift-E again to hide the cell expression, then close the style window.

 5. While the notebook is selected, go to Format -> Option Inspector, and select Selected Notebook under Scope.
 6. Search for DefaultNewInlineCellStyle and set it to InlineCode, the style you just created.  This will cause new inline cells to have this style.
 7. Additionally, under New Cell Defaults -> CommonDefaultFormatTypes, set `"TextInline"` to ????


  >>  I don't know what to set this to so when typing things like std::map then it won't be automtically formatted as a Mathematica message <<


 8. Now create a text cell in the notebook using Command-7, enter some text, then start an inline cell using Ctrl-(. You can exit the inline cell using Ctrl-).  This new inline cell will have the InlineCode style, as you can verify by revealing the cell expression (Command-Shift-E).