border-start-start-radius | CSS CSS Properties

Rounds the corner where the 'start' of the block (top) and the 'start' of the inline dimension (left in LTR) meet. This is the logical successor to 'border-top-left-radius'.

Quick example

.modern-box {
  /* Rounds the logical top-left corner */
  border-start-start-radius: 15px;
  padding: 1.5rem;
  border: 2px solid #333;
}

Quick facts

Initial value

0

Inherited

Applies to

all elements (UAs not required when collapse)

Animation type

lpc

Values

border-top-left-radius

border-start-start-radius Browser Support

Widely available Since 2021 95% global usage

This feature is well established and works across many devices and browser versions. It has been available across browsers since 2021.

Safe to use without fallbacks.

View on caniuse.com → View on MDN → View on webstatus.dev → Learn more about Baseline →

89+

66+

15+

89+