@media (max-width: 760px) {
  .container { width: min(calc(100% - 26px), 680px); }
  .section { padding: 66px 0; }
  .section-sm { padding: 44px 0; }
  .nav-shell { min-height: 68px; gap: 10px; }
  .website-link { display: none; }
  .auth-nav { margin-left: auto; }
  .auth-nav a { padding: 9px 10px; font-size: .76rem; }
  .brand-text span { display: none; }
  .hero { padding: 54px 0 60px; }
  .hero-copy h1 { font-size: clamp(2.7rem, 12vw, 4rem); }
  .hero-copy p { font-size: 1rem; }
  .hero-actions { display: grid; grid-template-columns: 1fr; }
  .hero-actions .btn { width: 100%; }
  .hero-proof { gap: 10px 14px; }
  .hero-visual { min-height: 360px; }
  .hero-card-main { left: 0; top: 24px; width: calc(100% - 28px); padding: 22px; }
  .hero-floating { right: 0; bottom: 12px; width: 185px; padding: 17px; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .stat-item:nth-child(2) { border-right: 0; }
  .stat-item:nth-child(-n+2) { border-bottom: 1px solid var(--border); }
  .card-grid { grid-template-columns: 1fr; }
  .challenge-section { padding: 64px 0; }
  .challenge-stats { flex-direction: column; align-items: flex-start; }
  .answers { grid-template-columns: 1fr; }
  .question-card, .full-question-card, .progress-panel, .streak-panel, .company-panel, .promo { padding: 23px; }
  .leaderboard-head { display: none; }
  .leader-row { grid-template-columns: 42px minmax(0,1fr); gap: 11px; padding: 13px 11px; }
  .points-cell, .streak-cell { grid-column: 2; text-align: left; font-size: .72rem; }
  .points-cell::before { content: "Points  "; color: var(--muted-2); font-weight: 700; }
  .streak-cell::before { content: "Streak  "; color: var(--muted-2); font-weight: 700; }
  .metric-grid { grid-template-columns: 1fr; }
  .calendar-toolbar { align-items: flex-start; flex-direction: column; }
  .calendar-grid { gap: 4px; padding: 8px; }
  .calendar-day { min-height: 50px; padding: 6px; }
  .calendar-day .day-name { font-size: .54rem; }
  .calendar-day strong { font-size: .68rem; }
  .company-panel { gap: 22px; }
  .footer { margin-top: 60px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 27px 18px; padding: 44px 0 26px; }
  .footer-brand { grid-column: 1 / -1; }
  .footer-bottom { flex-direction: column; gap: 8px; }
  .page-hero { padding: 48px 0; }
  .page-shell { padding: 44px 0 64px; }
  .challenge-page-grid { gap: 18px; }
  .submit-row { flex-direction: column; align-items: stretch; }
  .submit-row .btn { width: 100%; }
  .login-page { min-height: calc(100vh - 68px); padding: 32px 0; }
  .login-card { padding: 25px; }
}

@media (max-width: 430px) {
  .brand-text strong { font-size: .9rem; }
  .brand-mark { width: 34px; height: 34px; border-radius: 10px; }
  .auth-login { display: none; }
  .hero-copy h1 { letter-spacing: -.045em; }
  .hero-card-top { align-items: flex-start; flex-direction: column; gap: 8px; }
  .hero-card-main h3 { font-size: 1.05rem; }
  .hero-floating { width: 156px; }
  .stats-grid { grid-template-columns: 1fr; }
  .stat-item { border-right: 0; border-bottom: 1px solid var(--border); }
  .stat-item:last-child { border-bottom: 0; }
  .calendar-day { min-height: 47px; }
  .calendar-day .day-name { display: none; }
  .calendar-day strong { text-align: center; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-brand { grid-column: auto; }
}