The style of the link should distinguish different states through pseudo-classes. 1. Use a:link to set the unreached link style, 2. a:visited to set the accessed link, 3. a:hover to set the hover effect, 4. a:active to set the click-time style, 5. a:focus ensures keyboard accessibility, always follow the LVHA order to avoid style conflicts. You can improve usability and accessibility by adding padding, cursor:pointer and retaining or customizing focus outlines. You can also use border-bottom or animation underscore to ensure that the link has a good user experience and accessibility in all states.

SemanticHTMLimprovesbothSEOandaccessibilitybyusingmeaningfultagsthatconveycontentstructure.1)ItenhancesSEOthroughbettercontenthierarchywithproperheadinglevels,improvedindexingviaelementslikeand,andsupportforrichsnippetsusingstructureddata.2)Itboostsa

User agent stylesheets are the default CSS styles that browsers automatically apply to ensure that HTML elements that have not added custom styles are still basic readable. They affect the initial appearance of the page, but there are differences between browsers, which may lead to inconsistent display. Developers often solve this problem by resetting or standardizing styles. Use the Developer Tools' Compute or Style panel to view the default styles. Common coverage operations include clearing inner and outer margins, modifying link underscores, adjusting title sizes and unifying button styles. Understanding user agent styles can help improve cross-browser consistency and enable precise layout control.

To create an HTML unordered list, you need to use a tag to define a list container. Each list item is wrapped with a tag, and the browser will automatically add bullets; 1. Create a list with a tag; 2. Each list item is defined with a tag; 3. The browser automatically generates default dot symbols; 4. Sublists can be implemented through nesting; 5. Use the list-style-type attribute of CSS to modify the symbol style, such as disc, circle, square, or none; use these tags correctly to generate a standard unordered list.

To achieve CSS element overlap, you need to use positioning and z-index attributes. 1. Use position and z-index: Set elements to non-static positioning (such as absolute, relative, etc.), and control the stacking order through z-index, the larger the value, the higher the value. 2. Common positioning methods: absolute is used for precise layout, relative is used for relatively offset and overlap adjacent elements, fixed or sticky is used for fixed positioning of suspended layers. 3. Actual example: By setting the parent container position:relative, child element position:absolute and different z-index, the card overlap effect can be achieved.

Use the onclick attribute in HTML to directly bind click events, which is suitable for simple scenarios but is not conducive to code maintenance; 2. The onclick attribute assignment function of elements in JavaScript is more conducive to separating structures and behaviors, but will overwrite the previous event handler; 3. It is recommended to use the addEventListener method to support multiple event monitoring and better control the event flow, and should operate after the DOM is loaded to avoid common errors such as premature access to elements or quotation conflicts in HTML. Therefore, onclick is suitable for beginners and small projects, while addEventListener is more suitable for complex applications.

Backdrop-filter is used to apply visual effects to the content behind the elements. 1. Use backdrop-filter:blur(10px) and other syntax to achieve the frosted glass effect; 2. Supports multiple filter functions such as blur, brightness, contrast, etc. and can be superimposed; 3. It is often used in glass card design, and it is necessary to ensure that the elements overlap with the background; 4. Modern browsers have good support, and @supports can be used to provide downgrade solutions; 5. Avoid excessive blur values and frequent redrawing to optimize performance. This attribute only takes effect when there is content behind the elements.

The best use scenario for CSS will-change attribute is to inform browser elements in advance of possible changes in order to optimize rendering performance, especially for animation or transition effects. ① It should be applied before the animation properties (such as transform, opacity or position) changes; ② Avoid premature use or long-term retention, and should be set before the change occurs and removed after completion; ③ It should only be used for necessary properties rather than using will-change:all; ④ Suitable for scenarios such as large scrolling animations, interactive UI components, and complex SVG/Canvas interfaces; ⑤ Modern browsers can usually optimize automatically, so there is no need to use will-change in all animations. Proper use can improve