WhyCSS Inspector icon

WhyCSS Inspector

by abhixd · Developer Tools
Manifest V3 Free
View in Chrome Web Store Data as of 16 Oct 2026

Instantly diagnose why a CSS rule isn't applying

Users
5
−1 in 30 days
Rating
5.0 / 5
unchanged in 30 days
Ratings
1
0 in 30 days
Store rank
#245K
#205K among extensions
Version
1.0
updated 24 Apr 2026

Users

monthly, 6 months
025Apr 2026Aug 2026Oct 2026
Latest, 16 Oct 2026: 5 usersMove the mouse over the chart for any month

Ratings count

monthly, 6 months
001Apr 2026Aug 2026Oct 2026
Latest, 16 Oct 2026: 1 ratingsMove the mouse over the chart for any month

The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.

About WhyCSS Inspector

WhyCSS is a straightforward developer tool that helps you figure out exactly why a CSS property isn't being applied to an element. We've all been there: you write a CSS rule, refresh the page, and nothing happens. Instead of digging through the default DevTools trying to trace a massive stylesheet cascade, you can just click the WhyCSS icon (or right-click an element) to open it in your side panel. It breaks down exactly what rules are hitting the element, what properties are being overridden, and gives you the exact specificity score for each rule so you can clearly see who is winning the specificity war. FEATURES: • See all CSS rules applied to an element in one clean, readable table. • Specificity scores (e.g., 0,1,1) are calculated and listed next to every rule. • Properties that are overridden by stronger rules are crossed out. • Hover over a rule in the panel to highlight the matching elements on the live page, so you know exactly what a confusing selector is actually targeting. • Built-in diagnostic hints spot basic problems (like layout conflicts or accessibility contrast issues). • A built-in tab manager inside the side panel lets you keep track of elements across different browser tabs without losing your place. PRIVACY: This extension is built to be extremely lightweight and respects your privacy. It only runs when you explicitly click the action button or select the context menu option. It only uses the activeTab permission, meaning it has zero access to your browsing data until you actively choose to inspect a page, and no data is ever collected or sent off your machine.

Growth

WindowUsersChangeRatingsRating
7 days0+0.0%00.00
30 days−1−16.7%00.00

Version history

1 versions recorded
1.024 Apr 2026

Details

Category
Developer Tools
First seen
24 Apr 2026
Size
556 KB
Languages
en
Pricing
Free
Extension ID
niphcgpnfjegkkigmeijjpipdlkginhc

Permissions and risk

Moderate riskimpact 3, likelihood 2
Permissions
activeTabcontextMenusscriptingsidePaneltabs
Site access
<all_urls>
Can read and change data on every website you visit.

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