In this help center, you can find content for both Merchant Center Next and the classic Merchant Center experience. Look for the logo at the top of each article to make sure you're using the article for the Merchant Center version that applies to you.
CSS Troubleshooters
To find step-by-step instructions to resolve account-level issues, go to the Diagnostics page within your Merchant Center account, locate the issue, and click on the "Learn more" link.