not accurate in size

If you create a 1366x768 option or a 1280x800 option, it will be incorrect, too small.

This can be verified at browserstack.com or by hovering over the body tab in Chrome dev tools when visiting this URL: chrome://settings.

Instead of 1366, you will see 1350. I have seen this before with another tool, It was always off by 16px; therefore the fix was to add 16px to get the desired setting.