Change custom logo size

Hello,
My designer has provided me with a logo in a .png file sized 1385 width x 133 height. Can you please tell me how to adjust the code (or use custom CSS) to best display this file as my custom logo?

Thank you

 

Paste this code in Custom CSS
Appearance > Theme Option > Styling Option > Custom CSS

Code:

.header .logo img {
width: 550px;
}