Drupal submenu is not visible clearly.

Hi @alok_singh , i have tested this issue in drupal 9.5.x.
Patch failed to apply , showing below erros:-

<stdin>:24: trailing whitespace.
        {{page.slider}}
<stdin>:41: trailing whitespace.
        {{page.slider}}
warning: yg_fitness_gym.info.yml has type 100644, expected 100755
warning: 2 lines add whitespace errors.

please look into it.
Thanks.

@alok_singh I also tested your patch and its working as expected, but custom.css file is not a proper way to add in theme folder instead of that you can add in style.css file.