This is so random but a friend of mine was having troubles changing her blog's sidebar color using the new blogger interface's "Simple Template" and have asked me for help since I'm also using the new blogger interface's simple template for my biz blog. Well, ok, so I'm no expert LOL, but I thought I'd share how I edited mine just in case anybody else out there is having the same problem.
Again, this is for the New Blogger Interface "Simple Template"...
First: Go to Template >> Edit HTML >> Proceed
Second: Press "ctrl+f" for windows or "command+f" for mac and find the code below
Third: Right above that code, copy and paste this code below
Fourth: So it should look like this
Last: Click Preview or Save Template and you're done! :)
And yes, it is just a simple css code but with this simple code, you can really do so much more! Change the background color to your desire, add border if you wish and all that jazz! LOL!
Nothing fancy but hopefully, it's how you want it and will work for you too! Good luck! :)
For more details: Check Out Part 2!