Image border code needed

Hi,

i need to change the color of the border around the main picture on my site (http://www.rabeeatahir.com/). The color right now is white and i need to change it to #b5b5b5(gray) and need a css code

Also on this articles page(http://www.rabeeatahir.com/articles/) i need to do the same with all featured images and change their borders to #442625(purple) and need a code for custom css manager

Thanks a lot!

https://ww.wp.xz.cn/plugins/css/