<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title>Example of CSS3 Rounded Corners</title> <style> .box { width: 310px; height: 160px; background: skyblue; border: 4px solid orange; border-radius: 25px; } </style> </head> <body> <div class="box"></div> </body> </html>