DevTools responsive mode has one limitation that's never been fixed: you see one device at a time. You check iPhone. Looks fine. Switch to iPad. Fix padding. Switch back to iPhone. Was the header already broken or did you just break it? I got tired of holding layouts in my head, so I built a tool that shows all three at once. Responsive Tool — free, no signup Paste a URL → phone, tablet, and desktop load at one time. That's it. A few things that make it actually...