Buttons header

Hi guys,

I don’t know why my buttons don’t show up when i log out from wordpress. I change color of the buttons in additional css – it’s anything else I should do ?

that’s the code i used

.red-btn{
background: #0040ff !important;
}

.red-btn:hover{background:#3366ff !important;}

.green-btn{
background: #000000 !important;
}

.green-btn:hover{background:#333333 !important;}

#ribbon_bottom{
background:#89b2f4 !important;
}

Thanks for help