CSS Does Not Work For All Pages

Question

Hi,  

I have tried adding a reference to a CSS sheen in my own custom Master Page and also setting up an Alternate CSS (at https://xxx.sharepoint.com/\_layouts/15/ChangeSiteMasterPage.aspx ) but the CSS is not loaded at all on some pages.  

For example, I have https:/xxx.sharepoint.com/SitePages/Custom_Home.aspx. This page for example is a different type of Web Part page that does not have all the Web Parts I am used to has new Web Parts. 

There is no Ribbon just this.

The Web Part selector looks like this.

All I am trying to do is have my custom CSS effect every page.  I used to be able to do this by just changing the Master Page and I am not sure why this has become so hard. 

Thanks in advance for any help!

-Steve

Answer 1

Hi Steve,

According to Use CSS to brand SharePoint pages, this extensibility option is only available for classic SharePoint experiences. You cannot use this option with modern experiences in SharePoint Online, like with communication sites.

If you want to add Custom CSS to Modern Pages. Here is a thread in StackExchange Community for your reference.  

Regards,

Eric

Answer 2

It's hard to grasp but Msft has changed the entire model underlying the modern ui, so everything users have spent years learning and building has been discarded, including customization via master pages. SP definitely needed improvement but a customer focused company would have taken the trouble to gradually upgrade an archaic platform without disregarding their customers' investment in it - but this is Msft, so they truly don't care how much chaos they cause.