How to add a custom theme / modify an existing one?

Theme location

Themes are located in the folder modules/pshowblog/views/themes_17/. You can edit them freely to adapt them to your store.
Templates for the entry list are located in the directory modules/pshowblog/views/themes_17/theme_name/list/
Templates for the entry page are located in the directory modules/pshowblog/views/themes_17/theme_name/page/
The directory name is the theme name.
The directory name cannot contain spaces or special characters.
To add a new entry list or entry page theme, create a new directory with the required files at the appropriate path.

Required files for the entry list theme:

custom-page.tpl - main tpl file of the theme
post-list.css - theme css file
post-list.tpl - theme tpl file
layouts-left.tpl - tpl file for the "5 posts in grid v1" theme in the hook settings
layouts-right.tpl - tpl file for the "5 posts in grid v2" theme in the hook settings

Required files for the entry page theme:

single-post.css - theme css file
single-post.tpl - theme tpl file
Required files for the theme:
list directory - folder with the entry list layout
page directory - folder with the entry page layout
screenshot.jpg - screenshot of the theme's appearance
thumb.jpg - thumbnail of the theme screenshot (this file is generated automatically)

It's best to copy the files from an existing theme and modify them freely.