html按键border,html - changing button tag border color - Stack Overflow

I have put an image in border-less button tag. When the button is selected with Tab, a brown border appears around the image. How do I change color of that rectangle from brown to white. Is is possible to have a white rectangle with inner and outer shadow of blue.

HTML

help

EDIT:

I can change highlight color by using style=outline-color:white

HTML

help

help

Here is my initial page load image and if I press Tab I get a highlight similar to what is shown

How do I increase the rectangle width.