/* ============================================================
   Student Utility Hub — Mobile CSS
   Mobile-first responsive design
   Breakpoints: 320px, 480px, 768px, 1024px, 1280px
   ============================================================ */

/* ============================================================
   MOBILE BASE (320px – 479px)
   ============================================================ */
@media (max-width: 479px) {

  /* Typography Scale */
  body {
    font-size: 16px;
    line-height: 1.6;
  }

  h1 { font-size: 2rem;    letter-spacing: -0.02em; }
  h2 { font-size: 1.625rem; }
  h3 { font-size: 1.375rem; }
  h4 { font-size: 1.125rem; }

  .section-title  { font-size: 1.625rem; }
  .section-subtitle { font-size: 1rem; }

  /* Spacing */
  .section   { padding: 2.5rem 0; }
  .section-sm { padding: 1.5rem 0; }

  /* Navigation */
  .navbar .container {
    gap: 0.75rem;
  }

  .nav-logo-tagline { display: none; }

  .nav-links { display: none; }
  .nav-hamburger { display: flex; }

  /* Hero */
  .hero {
    min-height: 40vh;
    padding: 3rem 0;
  }

  .hero h1 { font-size: 2rem; }
  .hero-subtitle { font-size: 0.9375rem; }
  .hero-badge { font-size: 0.75rem; padding: 4px 12px; }

  .hero-stats {
    flex-direction: column;
    gap: 1rem;
    align-items: center;
  }

  .hero-stat-num { font-size: 1.75rem; }

  /* Search */
  .search-input {
    padding: 0.875rem 1rem 0.875rem 3rem;
    font-size: 1rem;
  }

  .search-suggestions {
    max-height: 260px;
  }

  /* Category Cards */
  .category-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .category-card {
    padding: 1.25rem;
    flex-direction: row;
    align-items: center;
  }

  .category-icon-wrap {
    width: 56px;
    height: 56px;
    font-size: 1.5rem;
    flex-shrink: 0;
  }

  .category-card-content { flex: 1; }

  .category-card-arrow { margin-top: 0; }

  /* Tool Cards (horizontal scroll) */
  .tool-card {
    width: 240px;
    padding: 1.25rem;
  }

  /* Buttons */
  .btn { min-height: 48px; }
  .btn-lg {
    width: 100%;
    padding: 0.9375rem 1.25rem;
    font-size: 1rem;
  }

  .hero-cta-group {
    flex-direction: column;
    width: 100%;
    gap: 0.75rem;
  }

  .hero-cta-group .btn {
    width: 100%;
  }

  /* Footer */
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .footer-brand-desc { max-width: 100%; }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }

  .footer-bottom-links {
    flex-wrap: wrap;
    gap: 0.75rem 1.5rem;
  }

  /* Result Card */
  .result-value { font-size: 2.25rem; }

  .result-actions {
    flex-direction: column;
  }
  .result-actions .btn {
    width: 100%;
  }

  /* Forms */
  .form-input, .form-select, .form-textarea {
    font-size: 16px; /* Prevent zoom on iOS */
    min-height: 48px;
  }

  /* Toast */
  .toast-container {
    left: 1rem;
    right: 1rem;
    bottom: 1rem;
  }

  .toast {
    min-width: unset;
    width: 100%;
  }
}

/* ============================================================
   MOBILE LANDSCAPE / SMALL TABLET (480px – 767px)
   ============================================================ */
@media (min-width: 480px) and (max-width: 767px) {

  h1 { font-size: 2.5rem; }
  h2 { font-size: 2rem; }
  h3 { font-size: 1.625rem; }

  .hero h1 { font-size: 2.5rem; }

  /* Category cards: 2-column */
  .category-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .category-card {
    flex-direction: column;
    align-items: flex-start;
  }

  .category-icon-wrap {
    width: 64px;
    height: 64px;
    font-size: 1.75rem;
  }

  /* Tool Cards */
  .tool-card { width: 260px; }

  .hero-stats {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1.5rem;
  }

  .btn-lg {
    width: auto;
    min-width: 180px;
  }

  .hero-cta-group {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.75rem;
  }
}

/* ============================================================
   TABLET (768px – 1023px)
   ============================================================ */
@media (min-width: 768px) and (max-width: 1023px) {

  .container { padding: 0 1.5rem; }

  h1 { font-size: 3rem; }
  h2 { font-size: 2.25rem; }

  .hero h1 { font-size: 3.5rem; }

  /* Category: 2-col */
  .category-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Nav: Show some links, hide hamburger */
  .nav-links {
    display: none; /* Still hamburger on tablet */
  }
  .nav-hamburger { display: flex; }

  /* Footer: 2-col */
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }

  .footer-brand { grid-column: 1 / -1; }

  /* Tool cards */
  .tool-card { width: 280px; }
}

/* ============================================================
   DESKTOP (1024px+)
   ============================================================ */
@media (min-width: 1024px) {

  .nav-links { display: flex; }
  .nav-hamburger { display: none; }

  .category-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr 1fr;
  }
}

/* ============================================================
   TOUCH TARGETS (Universal)
   Ensure all interactive elements are ≥ 48px
   ============================================================ */
button,
a,
input,
select,
textarea,
[role="button"],
[tabindex] {
  -webkit-tap-highlight-color: transparent;
}

/* Minimum touch target */
.nav-link,
.nav-mobile-link,
.btn,
.footer-social-link,
.dark-toggle {
  min-height: 48px;
  min-width: 48px;
}

.footer-link {
  min-height: 44px;
  display: flex;
  align-items: center;
}

/* ============================================================
   MOBILE TYPOGRAPHY UTILITIES
   ============================================================ */
@media (max-width: 767px) {

  /* Smaller section labels */
  .section-label {
    font-size: 0.7rem;
    padding: 3px 10px;
  }

  /* Card paddings */
  .card { padding: 1.25rem; }
  .card-icon { width: 48px; height: 48px; font-size: 1.25rem; }
  .card-title { font-size: 1.125rem; }

  /* Form groups: full width on mobile */
  .form-row {
    flex-direction: column;
    gap: 1rem;
  }

  .form-row > * { width: 100%; }

  /* Page header */
  .page-header { padding: 2.5rem 0; }
  .page-header h1 { font-size: 2rem; }
  .page-header p { font-size: 1rem; }

  /* Result card */
  .result-card { padding: 1.25rem; }
  .result-value { font-size: 2.5rem; }

  /* Ad banner */
  .ad-banner { height: 60px; font-size: 0.75rem; }

  /* Horizontal scroll hint */
  .scroll-hint {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
  }
}

/* ============================================================
   SAFE AREAS (iPhone notch / Android)
   ============================================================ */
@supports (padding: max(0px)) {
  .navbar .container {
    padding-left: max(1rem, env(safe-area-inset-left));
    padding-right: max(1rem, env(safe-area-inset-right));
  }

  .footer {
    padding-bottom: max(2rem, env(safe-area-inset-bottom));
  }

  .toast-container {
    bottom: max(1.5rem, env(safe-area-inset-bottom));
  }
}

/* ============================================================
   REDUCED MOTION
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .hero-particle { display: none; }
}

/* ============================================================
   HIGH CONTRAST MODE
   ============================================================ */
@media (prefers-contrast: high) {
  :root {
    --card-border: #000000;
    --text: #000000;
    --bg: #ffffff;
  }

  [data-theme="dark"] {
    --card-border: #ffffff;
    --text: #ffffff;
    --bg: #000000;
  }
}

/* ============================================================
   PRINT STYLES
   ============================================================ */
@media print {
  .navbar,
  .dark-toggle,
  .hero-particles,
  .footer-social,
  .ad-banner,
  .toast-container,
  .nav-hamburger,
  .nav-mobile-drawer {
    display: none !important;
  }

  body {
    background: white;
    color: black;
    font-size: 12pt;
  }

  .container { max-width: 100%; }
  .card { break-inside: avoid; }
  a[href]::after { content: " (" attr(href) ")"; }
}