Hello @ahmedshakeel083
I am sorry to hear you have this issue but I could not replicate the same on my test site. Is the Custom Sidebar was the only plugin that was updated, or there were more plugins that updated at the same time?
The Custom Sidebars plugin should not affect the site’s stylesheet. Please clear browser cache and site’s cache to see if the site is back.
If the issue is still there, please run a test for conflict with another plugin.
Deactivate all other plugins, beside Custom Sidebars and check if the stylesheet and menu loading. If everything is well, activate one plugin at a time to find the one that causes this.
Follow the steps from the flowchart:
https://premium.wpmudev.org/wp-content/uploads/2015/09/Support-Process-Support-Process.gif
Please make sure to create a backup before running this test.
Previous versions of the plugin can be downloaded from this page:
https://ww.wp.xz.cn/plugins/custom-sidebars/advanced/
Let us know how it went!
Kind regards,
Nastia
