Chrome is the visual design elements that give users information about or commands to operate on the screen's content (as opposed to being part of that content). These design elements are provided by the underlying system — whether it be an operating system, a website, or an application — and surround the user's data.
What is a UI Chrome?
UI Design gives you the ability to edit a web page's CSS. Test out new designs, styles and images without coding. Live edit a web page's CSS and styling without touching a line of code.
What is content to chrome ratio?
Content-to-Chrome Ratio and Screen Size
And that ratio is modulated by the screen size. On a tiny screen, a navigation bar with 8 items easily consumes more than half the available screen space; it can displace content and make users scroll to get a sense of what the page is about.