Notification Box Padding

Hi!
I made some changes to my css for the notification box. It now appears nice on the desktop version but it doesn’t display as nice on the mobile version. I’d like the text in the main content box (not the box in the upper left) to be vertically and horizontally centered. This is the code I’m using:
div .avia_message_box .avia_message_box_title { font-size: 22px; }
.avia_message_box_content { font-size: 14px; }
.avia_message_box_content { text-transform: capitalize; }
.avia_message_box_content {
padding-top: 20px;
}

Thanks!