While WPML lets you easily translate your content into RTL languages, it doesn’t control the RTL layout of your theme. The display of right-to-left content is determined by the CSS rules of your WordPress theme.
If your theme and the plugins on your site come with RTL support for layouts, WPML applies the correct formatting to your site’s translations.
I would advise checking further with your theme support and making sure they support RTL or hire a contractor for custom coding service.
Other then that only way would be you add CSS rules each time as you are doing it now.
I'm using rehub them already they have this feature. rlt.css
but when i try to do my own code it not working, i mean on my custom.css file codes.
My Question is is there any option to do style formally only for ar?
The CSS language attribute you are using html[lang="ar"] is a correct way of targeting language only for CSS.
WPML does not have a specific feature for this, you could if the theme allows you to add custom CSS directly in the page builder for a specific page but that would be page-level CSS and not for the entire site.
You could also use the lang() selector for CSS, see here: hidden link).
