Installed phpliteadmin in a subdir. How do you install a theme?
Putting CSS in there does not reference the correct path.
The documentation is quite poor on this.
How exactly does your folder structure look like?
Having phpliteadmin in a subdir should not make a difference if you place the phpliteadmin.css in the same subdir.
This is how PLA searches for the theme:
First. you can configure the theme name in the config using $theme. E.g. set $theme='mytheme.css';
It then first searches for themes/$theme, in the example themes/mytheme.css
if that does not exist, it searches for $theme in the same directory where PLA is stored, e.g. search for mytheme.css there
you can also give subdirs of themes or the current folder like this: $theme='bla/ver1/theme.css'; would search for themes/bla/ver1/theme.css and bla/ver1/theme.css