Customizing Email Templates in CRM

Customizing Email Templates in CRM

Ive created an email in CRM templates and added a button to click but the button is green.  I would like to change the color to coordinate with our branding but can not located anywhere to do this.  As an alternative I tried uploading a image file to use but it will not format the image appropriately to use.  Any suggestions on how to customize the button color?