How Can I Ensure CSS Rules Apply Correctly When Using `min-width` in Media Queries?

Understanding CSS Specificity, Media Queries, and min-width

When implementing responsive web design using the "mobile first" approach, min-width allows designers to define CSS rules based on device width. However, challenges arise when overwriting CSS values, as the lower min-width may take precedence.

The Issue

An example demonstrates the problem:

@media only screen and (min-width: 600px) {
    h2 { font-size: 2.2em; }
}

@media only screen and (min-width: 320px) {
    h2 { font: normal 1.7em/2.1em Helvetica, sans-serif; }
}

Ideally, resolutions above 600px should display an h2 font size of 2.2em. However, the 1.7em declaration takes precedence.

The Resolution

Media queries operate on a specificity hierarchy, where the most specific ruleoverrides those with less specificity. In the example above, the first media query is more specific because it specifies a higher minimum width.

The correct approach is to reorder the media queries so that the more specific rule, which sets a font size of 2.2em, appears last:

@media only screen and (min-width: 320px) {
    h2 { font: normal 1.7em/2.1em Helvetica, sans-serif; }
}

@media only screen and (min-width: 600px) {
    h2 { font-size: 2.2em; }
}

This ensures that the desired CSS rule for resolutions above 600px takes effect, even if it has a lower min-width value.

The above is the detailed content of How Can I Ensure CSS Rules Apply Correctly When Using `min-width` in Media Queries?. For more information, please follow other related articles on the PHP Chinese website!