Decide on your target screens & layouts

Responsive design doesn't mean creating infinite layouts. It means identifying key points where your design needs to fundamentally change. These breakpoints typically align with device categories, but more importantly, they're where your content starts feeling cramped or broken.

Standard breakpoints have emerged from common device sizes: Desktop (1200+px wide) handles full layouts with multiple columns and sidebars. Tablet landscape (around 1024px) often maintains desktop layouts with tighter spacing. Tablet portrait (around 768px) usually stacks sidebars below the main content. Mobile (below 480px) stacks everything vertically.

These aren't rigid rules but starting points based on how content naturally needs to reorganize. A data table might need different breakpoints than a photo gallery. Your analytics can refine these choices — for example, if 40% of your users visit on 820px tablets, you might add a specific breakpoint there.