Some HTML is 'Optional'

ThemostreliablewaytoverticallyaligntextinCSSisusingFlexboxwithalign-items:center,whichworksforbothsingleandmultiplelinesoftextwithinacontainerofdefinedheight;alternatively,CSSGridwithplace-items:centerofferssimilarbenefitsforgrid-basedlayouts,whileli

position:relativekeepstheelementinthenormaldocumentflowandoffsetsitfromitsoriginalpositionwhilepreservingitsspace,makingotherelementsbehaveasifit’sstillthere.2.position:absoluteremovestheelementfromthedocumentflow,positionsitrelativetothenearestposit

The style of the link should be defined in order through pseudo-classes to ensure the correct effect. 1. Use a:link to set the unvisible link style; 2. Use a:visited to set the visited link; 3. Use a:hover to set the hover state; 4. Use a:focus to ensure keyboard accessibility; 5. Use a:active to set the click-time style; at the same time, use CSS attributes such as color, text decoration, margins, and background to enhance the appearance, and ensure sufficient contrast, do not rely on colors alone to distinguish links, retain or customize focus outlines to improve accessibility, and ultimately achieve a link style that takes into account both visual and usability.

Creating background patterns using CSS is a lightweight and flexible method that can be achieved through gradients, pseudo-elements or multi-layer backgrounds; first, you can create stripes or complex gradients through repeating-linear-gradient(), and then use multi-background overlay to achieve polka dots or checkerboard effects, and then add noise texture overlays through pseudo-elements. Finally, you need to consider responsiveness and accessibility to ensure high performance and readability, so that you can use CSS to generate high-definition patterns without pictures.

AssignmultipleclassesinHTMLbyseparatingclassnameswithspaces:.2.StyleeachclassindependentlyinCSS,suchas.btn,.btn-primary,and.large.3.Allclassstylesarecombinedontheelement,withconflictingpropertiesresolvedbyCSSorderandspecificity—laterormorespecificrul

prefers-reduced-motion improves accessibility by detecting whether the user sets reduced animations in the system. When the value of reduce is reduced, the animation should be disabled or simplified to avoid user discomfort. Use @media(prefers-reduced-motion:reduce) to override the default animation, set animation or transition to none to eliminate harmful motion effects, but retain slight animation effects such as color changes. At the same time, tests should ensure complete functions, so as to provide users with a safer and more comfortable browsing environment without affecting the core experience.

To control the scaling behavior of textarea, you need to use the resize attribute of CSS; 1. Set resize to both to allow horizontal and vertical scaling (default); 2. Set to horizontal to only allow width adjustment; 3. Set to vertical to only allow height adjustment; 4. Set to none to completely prohibit scaling; 5. Block and inline correspond to block-level and inline directions respectively; combined with properties such as min-height, max-width, etc., the scaling range can be limited, and this attribute is widely supported in modern browsers and is suitable for block-level elements whose overflow is not visible.

Pseudo-classesinCSSarekeywordsthatstyleelementsbasedonstate,position,orattributes,improvinginteractivityandreducingtheneedforextraHTMLclasses;theyareappliedusingacolon(:)syntaxlikeselector:pseudo-class,enablingdynamiceffectssuchasa:hover{color:red;}f