Responsive Mobile Landing Page Revamp

My landing page works fine on desktop, yet on smartphones the layout breaks and key sections shuffle out of view. I want it to feel seamless on mobile first—specifically on both iOS Safari and Android Chrome—without worrying about tablets or larger screens for now... (Budget: ₹600 - ₹800 INR, Jobs: CSS, Frontend Development, HTML, HTML5, JavaScript, Mobile Development, Web Development, Website Development)