#overlayWrapper { position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(255, 255, 255, 0.86); z-index: 1; } #overlayContent { background: white; top: 0; left: 0; bottom: 0; right: 0; margin: 1em; padding: 1em; border-radius: 0.3em; border: 2px solid #333350; position: fixed; min-height: 6em; } #overlayCloseButton { position: absolute; top: 0; font-size: 150%; color: rgba(51, 51, 80, 0.8); right: 0; } @media (min-width: 600px) { #overlayContent { width: 70%; transform: translateX(-50%) translateY(-50%); top: 50%; left: 50%; max-width: 40em; } }