Email marketers face unique challenges when balancing technical and aesthetic considerations when designing emails. Accessible and responsive design has become particularly complicated with the growing adoption of mobile and dark-mode users. In my presentation, I'd like to share how I optimize marketing emails for desktop and mobile applications, dark mode and light mode, and test/assess the impact of my design choices. I'd like to share techniques such as displaying/hiding elements based on device resolutions, designing images for optimal display (strokes/mid-tones for PNGs, larger but high-compression images for retina displays), and tests + litmus setup email marketers can leverage to ensure their marketing emails are highly responsive, visually accessible, and beautiful to engage with.