Fluid until a breakpoint

Level 8 of 10

Your goal

The box is full width (100%) by default. From a 600px viewport up, make it 400px wide and centred. Expected: 420px wide on the 420px stage; 400px wide at x = 150 on the 700px stage.

Must usemargin

Checked at 2 stage widths (420px, 700px) — every stage below has to match.

stage 420px

stage 700px

target content boxtarget outer edge (green = matched, red = not yet)

Feedback updates as you type, and your CSS is saved in this browser. Exact target numbers are in the Target panel.