It's possible to change the background color of the Threads Pane (message list) and Folder Pane (accounts and folders list), but it requires a bit of effort in setting up userChrome.css files. I suggest you start with using the Dark theme in Tools/Add-ons/Themes, and review this discussion that explains how to change the font size for these panes.

I use firefox it´s the same way to do the things?

Sorry but not change. when open thunderbird it´s white color and it´s that background color i want to change. I have cataract. Hope you can help me, because it´s difficult to see my mails. beowolf

Are you trying to change the background color of the Threads and Folder Panes or the background of the message body? For the latter, open Tools/Options/Display/Formatting/Fonts & Colors/Colors... and change the Text and Background settings. This will affect plain text messages, but not HTML content.

No not that. Do you see my attachment? It´s there i want to change the color from white to dark blue and write text as yellow. Please look the attachment

Select Help/Troubleshooting Information, click Open Folder to open the profile folder in Explorer. Close TB. Create a subfolder named chrome. In the chrome folder, create a new text file named userChrome.css, save it as File Type 'All Files *.*'. In the css file, copy this content:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

#folderTree,
#threadTree
{
  background-color: blue !important;
  color: yellow !important;
}

#threadTree treechildren::-moz-tree-cell-text(unread) {
-moz-appearance: none !important;
color: yellow !important;
}

When you restart TB, you will have yellow text on a blue background for the Threads and Folder Panes.

Have do same as you tell me. Still not function. Will make attachment so you can see. beowolf

That looks OK, except you put the css file in the Firefox profile folder, not the TB profile folder. Its default location is:

C:\Users\<winusername>\AppData\Roaming\Thunderbird\Profiles\<8charstring>.default

Or, select Help/Troubleshooting Information in TB, click Open Folder to open the profile folder in Explorer.

Thanks function now. The first way you tell me was same as i had to make this in firefox. If i want other color. how can i make change?

You can change blue or yellow to any colors you like by editing the css file and entering the hex color code, e.g. #030932 is a shade of navy.

https://htmlcolorcodes.com/

When open TB and select a email. The content of the mail is still white. Can that been change?

Change the colors in Options as explained in my 2nd reply above.

That i already have make but not function i TB when click on a email that is still white.

It only works for plain text messages, and you may have to adjust the Override setting in the Colors options.