Input
Output
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>50mm x 30mm Box</title> <style> div { width: 50mm; height: 30mm; background-color: mediumslateblue; color: white; display: flex; align-items: center; justify-content: center; font-size: 14px; border: 2px solid #222; margin: 20px auto; } </style> </head> <body> <div> 50mm wide × 30mm tall </div> </body> </html>