Huddle Landing Page with Alternating Blocks

What specific areas of your project would you like help with?

Anyone please explain what's the least minimum screen width where i should stop worrying about responsiveness (and don't worry even if page breaks there) or my page should be fully intact even when i reduce the width to impossibly small values. In other words, where do you draw the line?

Also how do you keep the a card with "absolute position" locked at place like other content?