I think google can help you with most of these, but here are some guesses:
1) This is maybe because of Retina displays? Remember that on retina, images must actually be 2x their pixel size.
2) go to your website in Chrome, open the develpor console, click "Audits" and "Perform an Audit". That'll give you lots of insights into what loads slowly, and what you can do to fix
3) yeah, CSS debugging can be a bitch. GLWT :D
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I think google can help you with most of these, but here are some guesses:
1) This is maybe because of Retina displays? Remember that on retina, images must actually be 2x their pixel size.
2) go to your website in Chrome, open the develpor console, click "Audits" and "Perform an Audit". That'll give you lots of insights into what loads slowly, and what you can do to fix
3) yeah, CSS debugging can be a bitch. GLWT :D