Why can't I change the color inside a simple radio button?

[Morris2]

Hi.

 

I changed the color of the submit button like this:

<input type="submit" value="SEND"style="background-color: #CC6600">

 

Why can't I change the color inside a simple radio button the same way:

<input type="radio" name="amount"style="background-color: #CC6600" value="50">

 

Looking for a simple no-css solution for now ...

 

I am using Safari on Mac.

 

Regards Morris