Reduce Main Thread Blocking Time

How to optimize tutoriaux.excalibur.com

Generic SiteScore: 82/100Analyzed May 2026Re-analyze this site

Reduce Main Thread Blocking Time

High Impact+12 points estimated

Why It Matters

Main thread is blocked for 3.9 seconds with excessive style/layout work preventing user interactions and degrading INP.

How to Fix

Identify and eliminate forced reflows causing 89ms of blocking time. Defer non-critical JavaScript execution using async/defer attributes. Break up long-running tasks into smaller chunks using setTimeout or requestIdleCallback to allow browser breathing room.

0Needs Improvement

What This Score Means

A score of 82 falls in the "Needs Improvement" range (50-89). While it is better than poor (0-49), you should aim for 90+ to provide an optimal user experience and maximize SEO benefits.

This site is slower than approximately 35% of similar sites. The main issues affecting performance are image optimization, JavaScript execution time, and layout stability.

Addressing these issues could improve your conversion rate by 15-20% and boost your search engine rankings.

Core Web Vitals Analysis

LCP

Largest Contentful Paint

2.3s
Good

Good: < 2.5s

Measures how long it takes for the main content to appear on screen

INP

Interaction to Next Paint

1272ms
Poor

Good: < 200ms

Measures how quickly the page responds to user interactions

CLS

Cumulative Layout Shift

0.04
Good

Good: < 0.1

Measures visual stability - how much content shifts during page load

AI Performance Analysis

This website has good performance with a score of 82/100, but there's significant room for improvement. The biggest issue is excessive main-thread work (3.9 seconds) caused primarily by style and layout calculations, which creates a concerning 1,270ms delay for user interactions. The site is also wasting 33KB of unused CSS and has render-blocking stylesheets that delay initial page rendering by nearly 500ms. Cleaning up the CSS, optimizing the layout calculations, and deferring non-critical styles could easily push this site into the 90+ performance range and dramatically improve user responsiveness.

Other Optimization Recommendations

Eliminate Render Blocking CSS

High Impact+8 points estimated

Why It Matters:

Two CSS files are blocking initial render for 484ms each, delaying both FCP and LCP metrics.

How to Fix:

Inline critical above-the-fold CSS directly in the HTML head section. Load non-critical CSS asynchronously using media='print' onload technique. Split the 51KB CSS bundle into critical and non-critical portions to reduce render blocking time.

Remove Unused CSS Rules

Medium Impact+5 points estimated

Why It Matters:

33KB of unused CSS (82% waste) increases download time and parsing overhead without providing value.

How to Fix:

Use CSS coverage tools in Chrome DevTools to identify unused rules. Remove unused selectors from the main CSS bundle. Consider CSS tree-shaking tools or manual cleanup of framework CSS that's not being utilized on this page.

Keep Your Site Fast After Optimization

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