SharePoint Online Wiki Homepage: Change Top Suite Bar Color (CSS)

To change the color of the top suite bar on a SharePoint Online Wiki homepage, add a Script Editor web part to the page and add the following CSS code:

#suiteBarTop, #O365_NavHeader, #O365_AppName, #O365_MainLink_NavMenu, #O365_MainLink_Bell, #O365_MainLink_Settings, #O365_MainLink_Help, #O365_MainLink_Me  

{

background: #0078d4 !important;

}

That's it. Enjoy.