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  • What is the @extend directive in Sass and what are its dangers?
    What is the @extend directive in Sass and what are its dangers?
    @extend can share styles in Sass, but it may cause CSS confusion. The core problems are: 1. Selector explosion: generates a large number of combined selectors when expanding multiple classes; 2. Unexpected output: Nested or pseudo-class extensions may generate invalid CSS; 3. Debugging difficulty: It is difficult to distinguish between direct and inherited styles. Mixin or % placeholders should be used first to avoid problems.
    CSS Tutorial . Web Front-end 742 2025-06-28 00:58:21
  • How can you hide content accessibly?
    How can you hide content accessibly?
    Tohidecontentwhilekeepingitaccessible,useCSStechniqueslikethevisually-hiddenclasswithclipandpositionproperties.1.Applyposition:absoluteandcliptomovecontentoff-screenwhilekeepingitavailabletoscreenreaders.2.Useamodernapproachwithclip-pathandwhite-spac
    CSS Tutorial . Web Front-end 845 2025-06-28 00:53:21
  • What is the impact of overly complex CSS selectors on performance?
    What is the impact of overly complex CSS selectors on performance?
    Using an overly complex CSS selector can affect performance because the browser parses the selector from right to left, resulting in an increase in lookup and backtracking operations. For example, .sidebarullia:hover needs to check each link, list item, unordered list and sidebar container layer by layer. The deeper the nesting, the more specific the selector, and the heavier the processing burden. In addition, high specificity makes CSS difficult to maintain, forcing developers to use more complex rules to override the original style, and even rely on!important. To improve efficiency, deep nesting, use semantic class names (such as .nav-link), reduce the use of combinators, and use tools to audit verbose selectors. Although small websites have little impact, on large pages or mobile devices, the simplified selector can be displayed.
    CSS Tutorial . Web Front-end 160 2025-06-28 00:43:21
  • What is a good video CSS tutorial on YouTube?
    What is a good video CSS tutorial on YouTube?
    TofindasolidCSSvideotutorialonYouTube,prioritizeup-to-datecontent,clearexplanations,andhands-oncoding.1.Choosebeginner-friendlyseriesfromchannelslikeTraversyMediaorTheNetNinjathatwalkthroughrealprojectsandcoverFlexbox,Grid,andresponsivedesign.2.Ensur
    CSS Tutorial . Web Front-end 791 2025-06-28 00:27:50
  • How to create a responsive navbar CSS tutorial
    How to create a responsive navbar CSS tutorial
    To create a responsive navigation bar, the key is to use Flexbox layouts and media queries. 1. Use HTML to build a clear structure, including logo, link list and hamburger buttons; 2. Use Flexbox to implement horizontal arrangement on the desktop; 3. The mobile terminal hides the menu through media query and displays the hamburger buttons, combining JS control to expand and close; 4. Add transition animations to improve the interactive experience, and optimize the style details under different devices.
    CSS Tutorial . Web Front-end 130 2025-06-28 00:20:10
  • What is the correct order for link pseudo-classes like :link, :visited, :hover, and :active in CSS Selectors?
    What is the correct order for link pseudo-classes like :link, :visited, :hover, and :active in CSS Selectors?
    In CSS, the order of pseudo-class selectors: link, visited, :hover and :active is very important. They must be written in the order of LVHA (Link→Visited→Hover→Active), because if the styles are of the same priority, the subsequent rules will override the previous one; 1.:link sets the unvisible link style; 2.:visited sets the accessed link style, but is subject to browser privacy restrictions; 3.:hover sets the mouse hover effect, and the mobile terminal may need additional processing; 4.:active sets the style when clicking to provide instant feedback; this order ensures that all statuses can be displayed correctly to avoid browser inconsistencies.
    CSS Tutorial . Web Front-end 971 2025-06-28 00:02:21
  • How does the auto-fit vs auto-fill keyword work in repeat()?
    How does the auto-fit vs auto-fill keyword work in repeat()?
    Thedifferencebetweenauto-fitandauto-fillinCSSGridisthatauto-fillcreatesasmanytracksaspossiblewithoutresizingthem,leavingextraspace,whileauto-fitresizesthetrackstofilltheavailablespace.1.auto-fillmaintainsconsistenttracksizesandleaveswhitespaceifneede
    CSS Tutorial . Web Front-end 854 2025-06-27 01:42:30
  • What are the :focus and :focus-within pseudo-classes?
    What are the :focus and :focus-within pseudo-classes?
    :focus is used to directly focus the element itself, and :focus-within is used to affect the parent container when the child element gets focus. 1.: focus only takes effect on the current element and is often used for input box highlighting; 2.: focus-within is applied to containers containing interactive elements, and when their child elements are focused, triggering style changes, such as the overall highlighting of form groups or search box; 3. When using it, you should ensure accessibility, retain clear focus indicators, and combine them with keyboard navigation tests. Together, the two improve the usability and user experience of the interface.
    CSS Tutorial . Web Front-end 348 2025-06-27 01:40:21
  • When should you use JavaScript animations over CSS animations?
    When should you use JavaScript animations over CSS animations?
    JavaScript is a better choice. Situations where complex logic or interaction is required, such as condition-based animation chains, user input responses (drag and scroll effects); when state management is used for JavaScript, it facilitates animation and state synchronization; and when animation playback and time is required, such as pause, reversal, positioning, etc. through WebAnimationsAPI. In these three types of scenarios, JavaScript animation is better than CSS animation.
    CSS Tutorial . Web Front-end 417 2025-06-27 01:38:40
  • How do the adjacent and general ~ sibling combinators work in CSS Selectors?
    How do the adjacent and general ~ sibling combinators work in CSS Selectors?
    In the CSS selector, it is the adjacent sibling selector, and only the B element immediately after element A is selected; ~ is a general sibling selector, and all B elements of the same level are selected after element A are selected. For example, h2 p{color:red;} only the first paragraph turns red; while h2~p{font-weight:bold;} makes all subsequent paragraphs bold. Both require elements to be at the same level, and only the subsequent brothers can be selected and cannot be reversed. When using it, you need to pay attention to the structure order and nesting issues.
    CSS Tutorial . Web Front-end 340 2025-06-27 01:35:01
  • How do you select elements that have no children or text using the :empty pseudo-class in CSS Selectors?
    How do you select elements that have no children or text using the :empty pseudo-class in CSS Selectors?
    The:emptypseudo-classinCSSselectselementsthathavenochildrenortextcontent,butithasspecificcriteriaandlimitations.Touseit,apply:emptydirectlytotheselector,suchasdiv:empty,whichhidestrulyemptyelements;however,evenwhitespaceorcommentsinsideanelementmakei
    CSS Tutorial . Web Front-end 769 2025-06-27 01:34:20
  • What is CSS-in-JS and what are its pros and cons?
    What is CSS-in-JS and what are its pros and cons?
    CSS-in-JS is a method of directly managing component styles through JavaScript. Its core advantages include 1. Scope styles avoid conflicts, 2. Dynamic styles are more flexible, and 3. Rich tool support. It improves maintainability by binding styles to components, and achieves efficient development with libraries such as styled-components, emotion, etc., but it also has disadvantages such as runtime performance overhead and increased build time. It is suitable for project scenarios that require highly dynamic or componentization.
    CSS Tutorial . Web Front-end 457 2025-06-27 01:26:31
  • What is margin collapsing and how does it happen?
    What is margin collapsing and how does it happen?
    Margin folding in CSS refers to the phenomenon that the vertical margins of adjacent elements are merged into one margin, which mainly occurs in three situations: 1. Between the parent element and the first or last child element; 2. Between the adjacent brother elements; 3. Between the upper and lower margins of empty elements. For example, the upper and lower margins of two consecutive paragraphs will be combined into the larger value instead of adding them; when the parent element has no border or inner margin, the outer margin of the child element will affect the parent element's position; you can prevent collapse by adding inner margins, borders, or setting overflow attributes. Margin folding only occurs in the vertical direction, does not occur in the horizontal direction, and does not occur in the case of using flex, grid layout, or in the presence of floating or absolute positioning.
    CSS Tutorial . Web Front-end 236 2025-06-27 01:18:41
  • How do you make grid items span multiple columns or rows?
    How do you make grid items span multiple columns or rows?
    In CSSGrid, to make grid items span multiple columns or rows, you need to use grid-column and grid-row attributes. 1. Use grid-column to define the column span, such as grid-column:2/4 means starting from the second column line and span to the fourth column line, or use the span keyword such as grid-column:2/span2 means span 2 columns from the second column line; 2. Use grid-row to define the row span, such as grid-row:1/span2 means span 2 rows from the first row line, or can also be written as grid-row:1/3; 3. Set grid-column and grid-row at the same time to achieve a two-dimensional span, such as grid-
    CSS Tutorial . Web Front-end 778 2025-06-27 01:14:00

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