Accessibility considerations aren't limited to the content of a page, there are also configuration options in the <head> to bear in mind.
Every page must have a <title> element, without one a page will fail an accessibility audit because assistive technologies use this to introduce your page. You can set the value of the title element in Form Properties > Texts.
Many pages use the <meta content="viewport"> element to control the viewport. A page will fail an accessibility audit if this element contains user-scalable="no" or maximum-scale is less that 5.
By default these attributes aren't included, so users can zoom in on the page as much as they like. Adding these attributes detrimentally affects the experience for users with low vision.