What Is Critical CSS in WordPress?

Critical CSS is a performance optimization technique used in WordPress to improve how quickly a page becomes visible.

Normally:

• The browser loads all CSS files first
• Then it shows the page content
• This can delay page rendering

With Critical CSS:

• Only the “above-the-fold” styles (visible area) load first
• The rest of the CSS loads later in the background
• The page appears much faster to users

“Above the fold” means the part of the page users see without scrolling.

What Critical CSS includes:

• Layout structure (header, menu, hero section)
• Basic fonts and colors
• Visible images styling

Why it matters:

• Faster initial page display (improves LCP)
• Better Core Web Vitals score
• Improved user experience
• Less render blocking