model, which is a feature that allows the web designer to specify dimensions, padding, borders, and margins, and was the focus of the original Acid1 test. Acid2 not only retests margin support but also tests minimum and maximum heights and widths, features new to CSS 2.0. CSS table formatting, which allows the web designer to apply table formatting without traditional HTML table markup on the CSS. CSS generated content, Using CSS generated content, web developers can add decorations and annotations to specified elements without having to add the content to each one individually. CSS parsing, in which a number of illegal CSS statements are present in Acid2 to test error handling. Standards-compliant browsers are expected to handle these errors as the CSS specification directs. This helps ensure cross-browser compatibility by making all browsers treat CSS with the same level of strictness, so that what works in one browser should not cause errors in another. Paint order, which means that Acid2 requires that the browser has standard paint order. That is, overlapping elements should be placed or painted on top of each other in the correct order, and finally Hovering effects, which is When the user moves his or her mouse over the smiley face's nose, it turns blue. This is called a hovering effect, and while it has traditionally been used for hyperlinks, it should work on a wide variety of HTML elements. Because Acid2 is not a comprehensive test, it does not guarantee total conformance to any particular standard. A variant of the Acid2 test that does not test for data URI support is also available from the Web Standards Project. Passing conditions A passing score is only considered valid if the browser's default settings were used. Actions such as changing font sizes, zoom level, and applying user stylesheets can break the display of the test. This is expected and is not relevant to a browser's compliance. These browser settings and user actions invalidate the test, which are: Scrolling, Resizing the browser window, Zooming in or out, Disabling images, Using Opera's Fit to width or Small Screen Rendering modes, Applying custom fonts, colors, styles, etc., User JavaScript or Greasemonkey scripts, Enabling Internet Explorer's "compatibility view" Compliant applications If rendered correctly, Acid2 will appear as a smiley face below the text "Hello World!" in the user's browser, with the nose turning blue when the mouse cursor hovers over it. At