fix: Mobile Responsive Polish for 375px and 768px Breakpoints

[Humoudideas77]

Closes #824

Bounty: Mobile Responsive Polish

Tier: T1 | Reward: 150,000

Summary

Full mobile responsive polish across all pages. Every page renders correctly at 375px and 768px with no horizontal scroll.

Changes (12 files)

Navigation

• Navbar: Responsive logo sizing (w-6 h-6 → sm:w-7 sm:h-7), adaptive gap (gap-6 lg:gap-8) prevents overflow at 375px
• Mobile hamburger menu already functional ✓

Home Page / Hero Section

• HeroSection: Terminal card scales (max-w-md sm:max-w-xl), responsive padding, smaller fonts at 375px
• Headline: text-3xl sm:text-4xl md:text-5xl — readable on all breakpoints
• CTAs: px-5 sm:px-6 py-2.5 sm:py-3 — comfortable touch targets
• Stats strip: stacks vertically on mobile, dot separators hidden
• Added mobile typewriter animation (animate-typewriter-sm) with adjusted steps

Bounty Cards & Grid

• BountyCard: Status badge moved from absolute positioning to document flow — no more overlap with reward text
• Reward + meta stacks vertically on mobile (flex-col sm:flex-row)
• BountyGrid: Responsive heading (text-xl sm:text-2xl)

Bounty Detail

• BountyDetail: Responsive padding, title scaling (text-lg sm:text-2xl)
• Back button + copy button layout wraps safely on mobile

Footer

• Footer: Grid now breaks at sm (1→2→4 columns) instead of md (1→4)
• Token address uses min-w-0 for safe truncation at 375px

Leaderboard

• PodiumCards: Responsive min-width (min-w-[110px] sm:min-w-[140px]) and padding, overflow-x-auto safety
• LeaderboardTable: overflow-x-auto (horizontal scroll instead of hidden)
• Page title: text-3xl sm:text-4xl

How It Works

• FlowTabs: Tab buttons scale (px-3 sm:px-5, text-xs sm:text-sm)
• Step flow maintains proper spacing on mobile
• Page title: text-3xl sm:text-4xl

CSS

• Cleaned up stale CSS selectors
• Added typewriter-sm keyframe animation for mobile
• Added universal box-sizing (including ::before, ::after)
• Removed broken .bounty-card-status selector

Acceptance Criteria

• All pages look correct at 375px width
• All pages look correct at 768px width
• No horizontal scroll on any page
• Build passes with zero errors
• Touch targets remain accessible on mobile

Wallet

humoudideas77