Weekly Platform News: Improving UX on Slow Connections, a Tip for Writing Alt Text and a Polyfill for the HTML loading attribute

CSS blocks page rendering because browsers view inline and external CSS as key resources by default, especially with imported stylesheets, header large amounts of inline CSS, and unoptimized media query styles. 1. Extract critical CSS and embed it into HTML; 2. Delay loading non-critical CSS through JavaScript; 3. Use media attributes to optimize loading such as print styles; 4. Compress and merge CSS to reduce requests. It is recommended to use tools to extract key CSS, combine rel="preload" asynchronous loading, and use media delayed loading reasonably to avoid excessive splitting and complex script control.

Autoprefixer is a tool that automatically adds vendor prefixes to CSS attributes based on the target browser scope. 1. It solves the problem of manually maintaining prefixes with errors; 2. Work through the PostCSS plug-in form, parse CSS, analyze attributes that need to be prefixed, and generate code according to configuration; 3. The usage steps include installing plug-ins, setting browserslist, and enabling them in the build process; 4. Notes include not manually adding prefixes, keeping configuration updates, prefixes not all attributes, and it is recommended to use them with the preprocessor.

Theconic-gradient()functioninCSScreatescirculargradientsthatrotatecolorstopsaroundacentralpoint.1.Itisidealforpiecharts,progressindicators,colorwheels,anddecorativebackgrounds.2.Itworksbydefiningcolorstopsatspecificangles,optionallystartingfromadefin

TocreatestickyheadersandfooterswithCSS,useposition:stickyforheaderswithtopvalueandz-index,ensuringparentcontainersdon’trestrictit.1.Forstickyheaders:setposition:sticky,top:0,z-index,andbackgroundcolor.2.Forstickyfooters,betteruseposition:fixedwithbot

The scope of CSS custom properties depends on the context of their declaration, global variables are usually defined in :root, while local variables are defined within a specific selector for componentization and isolation of styles. For example, variables defined in the .card class are only available for elements that match the class and their children. Best practices include: 1. Use: root to define global variables such as topic color; 2. Define local variables inside the component to implement encapsulation; 3. Avoid repeatedly declaring the same variable; 4. Pay attention to the coverage problems that may be caused by selector specificity. Additionally, CSS variables are case sensitive and should be defined before use to avoid errors. If the variable is undefined or the reference fails, the fallback value or default value initial will be used. Debug can be done through the browser developer

Mobile-firstCSSdesignrequiressettingtheviewportmetatag,usingrelativeunits,stylingfromsmallscreensup,optimizingtypographyandtouchtargets.First,addtocontrolscaling.Second,use%,em,orreminsteadofpixelsforflexiblelayouts.Third,writebasestylesformobile,the

There are three ways to create a CSS loading rotator: 1. Use the basic rotator of borders to achieve simple animation through HTML and CSS; 2. Use a custom rotator of multiple points to achieve the jump effect through different delay times; 3. Add a rotator in the button and switch classes through JavaScript to display the loading status. Each approach emphasizes the importance of design details such as color, size, accessibility and performance optimization to enhance the user experience.

To make the entire grid layout centered in the viewport, it can be achieved by the following methods: 1. Use margin:0auto to achieve horizontal centering, and the container needs to be set to set the fixed width, which is suitable for fixed layout; 2. Use Flexbox to set the justify-content and align-items properties in the outer container, and combine min-height:100vh to achieve vertical and horizontal centering, which is suitable for full-screen display scenarios; 3. Use CSSGrid's place-items property to quickly center on the parent container, which is simple and has good support from modern browsers, and at the same time, it is necessary to ensure that the parent container has sufficient height. Each method has applicable scenarios and restrictions, just choose the appropriate solution according to actual needs.