Metrics
| Indicator | Value |
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CSS stylesheet size (in kilobytes)
Calculates the size (in kilobytes) of the CSS stylesheet. |
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Total number of CSS rules
Calculates the total number of rules in the CSS stylesheet. |
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Average CSS rule length
Calculates the average length (in characters) of CSS rules. |
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Average CSS selector length
Calculates the average length (in characters) of CSS selectors. |
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Average CSS declaration length
Calculates the average length (in characters) of CSS declarations. |
Tests
| Test | Result |
|---|---|
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Does your CSS stylesheet need minification?
Tests for the presence of whitespaces except for inside comments. Consider minifying your CSS stylesheet to remove whitespaces and reduce its size. |
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Does your CSS stylesheet contain media queries?
Consider adding media attributes to the <link> or <style> element itself to make CSS files non-render blocking.
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Does your CSS stylesheet contain the universal (*) selector?
The universal selector in CSS is one of the CSS selectors with the poorest performance. |
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Does your CSS stylesheet contain attribute ([]) selectors?
Attribute selectors are usually slower than their regular counterparts. |
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Does your CSS stylesheet contain combinator (+, >, ~, ' ', ||) selectors?
Combinator selectors may or may not be slower; benchmark to find out the case for you. |
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Does your CSS stylesheet contain @import rules?
Using @import rules can slow down your website's loading.
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Does your CSS stylesheet contain @font-face rules?
There are performance implications of using custom fonts; consider swapping them out for web-safe fonts or limiting their use to a reasonable minimum. |
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Does your CSS stylesheet contain CSS variables?
CSS variables may slow down your website, especially if overused with the calc() function.
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Does your CSS stylesheet contain !important rules?
Excessive use of the !important rule may signal CSS bloat.
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Does your CSS stylesheet contain @keyframe animations?
Animations can be visually appealing, but they can also impact performance if misused. |