/* ═══════════════════════════════════════
   MOBILE — Bottom Nav, Touch, Safe Areas
   ═══════════════════════════════════════ */

*, *::before, *::after {
  -webkit-tap-highlight-color: transparent;
}

a, button, [role="button"], label, input, select, textarea {
  touch-action: manipulation;
}

/* ── App Nav: fixed bottom bar on ALL viewports ── */
body.has-app-nav {
  padding-top: 0;
  padding-bottom: 0;
  scroll-padding-bottom: calc(78px + env(safe-area-inset-bottom, 0px));
}

.app-nav {
  position: fixed;
  inset: auto 0 0 0;
  transform: translateZ(0);
  z-index: 1000;
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: calc(72px + env(safe-area-inset-bottom, 0px));
  margin: 0;
  padding: 10px max(14px, env(safe-area-inset-right, 0px)) calc(10px + env(safe-area-inset-bottom, 0px)) max(14px, env(safe-area-inset-left, 0px));
  border: 0;
  border-top: 1px solid rgba(255, 255, 255, 0.72);
  border-radius: 0;
  background:
    linear-gradient(180deg, rgba(255,255,255,0.88), rgba(255,255,255,0.97)),
    rgba(255, 255, 255, 0.94);
  box-shadow:
    0 -14px 36px rgba(26, 26, 46, 0.08),
    0 -1px 0 rgba(124, 92, 252, 0.08);
  box-sizing: border-box;
  -webkit-backdrop-filter: blur(22px) saturate(1.45);
  backdrop-filter: blur(22px) saturate(1.45);
  overscroll-behavior: contain;
}

/* Inner wrapper centres tabs at desktop width */
.app-nav-inner {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  align-items: center;
  gap: 5px;
  width: 100%;
  max-width: 560px;
  min-height: 54px;
  padding: 5px;
  border: 1px solid rgba(124, 92, 252, 0.10);
  border-radius: 24px;
  background:
    linear-gradient(180deg, rgba(255,255,255,0.96), rgba(248,248,252,0.94));
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.95),
    0 8px 22px rgba(26, 26, 46, 0.08);
}

.app-nav-tab {
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 12px;
  border: 1px solid transparent;
  border-radius: 18px;
  color: var(--text-muted);
  text-decoration: none;
  font-family: 'Nunito', sans-serif;
  font-weight: 900;
  position: relative;
  isolation: isolate;
  transition:
    transform 0.18s cubic-bezier(0.34, 1.56, 0.64, 1),
    background 0.18s ease,
    color 0.18s ease,
    box-shadow 0.18s ease;
}

.app-nav-tab:hover,
.app-nav-tab:focus-visible {
  color: var(--brand-dark);
  background: rgba(124, 92, 252, 0.08);
  border-color: rgba(124, 92, 252, 0.08);
  outline: none;
  transform: translateY(-1px);
}

.app-nav-tab--active {
  color: var(--brand-dark);
  background:
    linear-gradient(180deg, rgba(255,255,255,0.98), rgba(245,243,255,0.98));
  border: 1px solid rgba(124, 92, 252, 0.16);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.95),
    0 3px 10px rgba(124, 92, 252, 0.12);
  transform: none;
}

.app-nav-tab--active:hover,
.app-nav-tab--active:focus-visible {
  color: var(--brand-dark);
  background:
    linear-gradient(180deg, rgba(255,255,255,1), rgba(240,239,254,1));
}

.app-nav-icon {
  display: inline-grid;
  place-items: center;
  width: 24px;
  height: 24px;
  font-size: 21px;
  line-height: 1;
  transition: transform 0.22s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.app-nav-tab:hover .app-nav-icon,
.app-nav-tab--active .app-nav-icon {
  transform: translateY(-1px);
}

.app-nav-label {
  font-size: 13px;
  font-weight: 900;
  line-height: 1;
  letter-spacing: 0;
  text-transform: none;
  white-space: nowrap;
}

/* ── Desktop refinements ── */
@media (min-width: 769px) {
  .app-nav-inner {
    max-width: 580px;
  }

  .app-nav-tab {
    min-height: 46px;
  }
}

/* ── Mobile: taller, touch-optimised bottom nav ── */
@media (max-width: 768px) {
  body.has-app-nav {
    padding-top: 0;
    padding-bottom: 0 !important;
    scroll-padding-bottom: calc(80px + env(safe-area-inset-bottom, 0px));
  }

  .app-nav {
    min-height: calc(76px + env(safe-area-inset-bottom, 0px));
    padding: 8px max(10px, env(safe-area-inset-right, 0px)) calc(8px + env(safe-area-inset-bottom, 0px)) max(10px, env(safe-area-inset-left, 0px));
  }

  .app-nav-inner {
    max-width: 430px;
    min-height: 60px;
    gap: 3px;
    padding: 4px;
    border-radius: 22px;
  }

  .app-nav-tab {
    min-width: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    padding: 7px 4px;
    min-height: 52px;
    color: var(--text-muted);
    border-radius: 18px;
    background: transparent;
    box-shadow: none;
  }

  .app-nav-tab::before {
    display: none;
  }

  .app-nav-tab--active {
    color: var(--brand-dark);
    background:
      linear-gradient(180deg, rgba(255,255,255,0.98), rgba(245,243,255,0.98));
    border: 1px solid rgba(124, 92, 252, 0.16);
    box-shadow:
      inset 0 1px 0 rgba(255,255,255,0.95),
      0 3px 10px rgba(124, 92, 252, 0.12);
    transform: none;
  }

  .app-nav-tab:active {
    transform: translateY(0) scale(0.96);
  }

  .app-nav-icon {
    width: 24px;
    height: 24px;
    font-size: 23px;
  }

  .app-nav-label {
    font-family: 'Nunito', sans-serif;
    font-size: 11px;
    font-weight: 900;
    letter-spacing: 0;
    text-transform: none;
    line-height: 1;
    transition: color 0.2s ease;
  }
}

@media (max-width: 380px) {
  body.has-app-nav {
    padding-bottom: 0 !important;
    scroll-padding-bottom: calc(74px + env(safe-area-inset-bottom, 0px));
  }

  .app-nav {
    min-height: calc(72px + env(safe-area-inset-bottom, 0px));
    padding-inline: max(7px, env(safe-area-inset-left, 0px)) max(7px, env(safe-area-inset-right, 0px));
  }

  .app-nav-inner {
    min-height: 56px;
    border-radius: 20px;
  }

  .app-nav-tab {
    min-height: 48px;
    gap: 3px;
    padding: 5px 2px;
    border-radius: 16px;
  }

  .app-nav-icon {
    font-size: 21px;
  }

  .app-nav-label {
    font-size: 10px;
    letter-spacing: 0;
  }
}

@supports (padding-top: env(safe-area-inset-top)) {
  body > nav:not(.app-nav) {
    padding-top: max(0.7rem, env(safe-area-inset-top));
  }
}

@media (max-width: 768px) {
  .fc-page,
  .lesson-page,
  .reading-page {
    min-height: 100dvh;
  }
}

@media (max-width: 768px) {
  body {
    -webkit-overflow-scrolling: touch;
  }
}

@media (pointer: coarse) {
  *:focus { outline: none; }
  *:focus-visible {
    outline: 2.5px solid var(--brand);
    outline-offset: 2px;
    border-radius: 4px;
  }
}

button, a, .quiz-option, .practice-option, .comprehension-option,
.drill-option, .review-rate-btn, .vocab-rate-btn, .key {
  touch-action: manipulation;
  -webkit-user-select: none;
  user-select: none;
}

/* ── Haptic-Active State — press-down effect ── */
@media (pointer: coarse) {
  .btn:active,
  .fc-btn:active,
  .onboarding-btn:active,
  .build-tile:active,
  .key:active {
    transform: translateY(4px) scale(0.97) !important;
    transition: transform 0.08s ease !important;
  }
}