Designing mobile first

Designing mobile first means starting from the smallest screen and adding space only when there is room.

Why it works

1. It forces you to choose what really matters.
2. Text stays readable, in one column, with no horizontal scrolling.
3. Touch targets are large enough for fingers.

In practice

You write the base style for about 320 pixels first, then add rules for tablet and desktop. The result works well on every device.