How to change the transparent background?

Hello Hristo !
1. To change background DW Focus theme, you can add the following code to the Header Script:

 <style>
body {
    background: #...;
}
.container {
    background: #...;
}
#colophon.dark .container {
    background: #...;
}
</style>

2. Currently, Our DW Focus does not yet support to create separate color backgrounds for categories and to enable or disable color background in category style section.
3. Of course, you can, please do as the following:
Step1: Go to folder path “wp-content\themes\dw-focus\assets\colors”
Step2: Create new a folder with color title that you want to use. E.g: red / gray
Step3: Open the Blue folder, copy 3 file (img folder / style.css / style.less)
Step4: Open the folder that you created before, paste 3 file that you copied from Blue folder.
Step5: You change the logo in the img folder
– Change the color in the style.css & style.less
Hope this helps !