Modify Email Template footer style

Please try this 

On Master Email Template go to Templates tab > Click on Email Wrapper > on Editor Under Tools select source code .

navigate to the [Footer] option and change the color of the td in which the [Footer] Element resides in .

Satish Kumar (3sides) We have disabled the Fonts, Font sizes, Foreground colors, Backgrounds and Custom styles under "Administration" >> "Moderation" >> "Filtering" >> "Formatting". So even if we add style for "<td>" like "<td style='color: red'>" it automatically removes the style once saved in the source code.