CSS3 Border-radius (rounded corners)

Formal Definition

Specifications

CSS Backgrounds and Borders Module Level 4 # border-radius

Syntax

/* The syntax of the first radius allows one to four values */
 /* Radius is set for all 4 sides */
 border-radius: 10px;
 /* top-left-and-bottom-right | top-right-and-bottom-left */
 border-radius: 10px 5%;
 /* top-left | top-right-and-bottom-left | bottom-right */
 border-radius: 2px 4px 2px;
 /* top-left | top-right | bottom-right | bottom-left */
 border-radius: 1px 0 3px 4px;
 /* The syntax of the second radius allows one to four values */
 /* (first radius values) / radius */
 border-radius: 10px / 20px;
 /* (first radius values) / top-left-and-bottom-right | top-right-and-bottom-left */
 border-radius: 10px 5% / 20px 30px;
 /* (first radius values) / top-left | top-right-and-bottom-left | bottom-right */
 border-radius: 10px 5px 2em / 20px 25px 30%;
 /* (first radius values) / top-left | top-right | bottom-right | bottom-left */
 border-radius: 10px 5% / 20px 25em 30px 35em;
 /* Global values */
 border-radius: inherit;
 border-radius: initial;
 border-radius: revert;
 border-radius: unset;

References

Data sourced from

• The World Wide Web Consortium (W3C)
• CanIuse
• Mozzila MDN Web Docs
• Web.Dev
• Chrome Platform Status
• WebKit Feature Status