border-box changes the deal
Level 5 of 13Your goal
.box must exactly fill the dashed frame at both stage widths: 252px wide on the 420px stage and 420px wide on the 700px stage (the frame is 60% of the stage), 140px tall. Keep the 20px padding and 5px border.
Checked at 2 stage widths (420px, 700px) — every stage below has to match.
stage 420px
stage 700px
marginborderpaddingcontenttarget 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.