Yes, you can style text highlights using the ::selection pseudo-element. This pseudo-element targets the portion of text selected by the user, allowing you to customize its appearance without modifying the underlying HTML.

Key Points

1
::selection applies styles to text that the user highlights or selects.
2
You can style properties like color, background-color, and text-shadow.
3
Not all CSS properties are supported; for example, margin, padding, and border generally do not work.
4
It enhances user experience by matching selection styles to your site’s design or theme.

Example: Custom Text Highlight

In this example, when the user selects the paragraph text, the background turns blue and the text becomes white with a subtle shadow, enhancing readability and aesthetics.

Best Practices

1
Keep highlight colors with good contrast for readability.
2
Use subtle text shadows to improve visibility if needed.
3
Test across browsers, as older browsers may have partial support for ::selection.
4
Avoid applying ::selection to critical UI elements where text selection might interfere with functionality.

Difficulty: 3/10

Topics: pseudo-elements, text highlighting, CSS positioning

Scenario Questions

0-2 years experience

1
How would you highlight a single word inside a paragraph using only CSS, without adding extra HTML elements?
2
What happens if you try to style a pseudo-element on an <input> field — why doesn't it work?

2-5 years experience

1
A text highlight we added with ::before is cutting off on mobile — what could be causing it, and how would you debug it?
2
Our highlight works in Chrome but not Safari — what CSS properties might be inconsistently supported, and how would you fix it?

5-8 years experience

1
We're using pseudo-elements for dynamic text highlights in a rich text editor — how would you handle performance when highlighting hundreds of words in real-time?
2
How would you design a reusable highlight component that works with dynamic content, RTL layouts, and screen readers without breaking accessibility?

8+ years experience

1
We're migrating a legacy UI that uses inline spans for highlights to a pseudo-element-based system — what cross-team coordination and testing strategies would you propose to avoid visual regressions at scale?
2
How would you architect a theming system for text highlights across 20+ micro-frontends, balancing consistency, performance, and developer ergonomics without forcing a shared CSS library?

Follow-up Questions

❓What happens if the highlighted text wraps across multiple lines?
❓How would you ensure the highlight doesn't overlap adjacent elements?
❓Why can't you use pseudo-elements on self-closing tags like <img>?