Review your designs on the browser with draggable guides that measures pixel distances between the guides.
Add guides
Click the horizontal or vertical button to see guides overlayed on your website
Drag guides
Over your webpage and watch as it instantly measures pixel distances
Remove guides
Either one by one by clicking the X on each guide, or all at once with the trash icon
Viewport size
Viewport Size:
Displays your current viewport size so you know which media query to target