CSS specificity determines which styles are applied when there are conflicting rules targeting the same element. 1. Inline styles have the highest weight at 1000. 2. IDs count as 100 each. 3. Classes, pseudo-classes, and attributes are worth 10 each. 4. Elements and pseudo-elements add 1 point each. When selectors conflict, the one with higher specificity wins regardless of order in the stylesheet. Nesting or position only matters if specificity is equal. Combining selectors doesn't multiply values. Overusing !important should be avoided as it skips normal checks and complicates debugging. Managing specificity can be achieved by keeping selectors short, using classes more than IDs, checking browser dev tools for overridden styles, and applying a class-based approach when overriding third-party libraries.
CSS specificity determines which styles get applied when there are conflicting rules targeting the same element. It’s not always about which rule comes last in your stylesheet — sometimes, it's about how specific each selector is.
How Specificity Works
Every CSS selector has a weight based on its type. When multiple selectors target the same element, the one with higher specificity wins. Here's how to calculate it:
-
Inline styles (e.g.,
style="color: red") carry the highest base value: 1000. -
IDs (
#header) count as 100 each. -
Classes, pseudo-classes, and attributes (
.btn,:hover,[type="text"]) are worth 10 each. -
Elements and pseudo-elements (
div,::before) add 1 point each.
For example:
/* 100 (ID) 10 (class) = 110 */
#nav.active {}
/* 10 (class) 1 (element) = 11 */
nav.primary {}The first selector will override the second even if both match the same element.
Common Confusions
One thing that trips people up is thinking that nesting or being further down in the stylesheet always wins. That only matters when two selectors have equal specificity — otherwise, the more specific one takes priority regardless of order.
Also, combining selectors doesn’t multiply their values. Using div#main still gives you just 100 1 = 101, not more.
A common mistake? Overusing !important. It should be avoided unless absolutely necessary because it skips normal specificity checks and makes debugging harder later.
Tips for Managing Specificity
Here are some practical ways to keep things under control:
- Keep selectors short and avoid unnecessary nesting.
- Use classes more than IDs since they’re easier to override.
- If you're stuck trying to figure out why a style isn't applying, check the browser dev tools — they show computed styles and which rules are being overridden.
- When resetting or overriding third-party libraries, using a class-based approach helps maintain flexibility.
You don’t need to do math every time, but understanding the scale helps prevent frustration when styles aren’t behaving the way you expect.
That’s basically how specificity works — it's straightforward once you know how the numbers stack up.
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