/* ============================================================
   WAIKO Engineering — Design System v1.0
   偉高工程官方網站設計系統
   ============================================================ */

/* ── Google Fonts ── */
@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+TC:wght@400;700&family=Noto+Sans+TC:wght@400;500;700&display=swap');

/* ── Design Tokens ── */
:root {
  /* Colours */
  --color-primary:        #B53845;
  --color-primary-hover:  #962E39;
  --color-primary-dark:   #6E2229;
  --logo-en-color:        #B53845;
  --logo-zh-color:        #C94855;
  --color-accent:         #c8850a;
  --color-accent-hover:   #a86d08;
  --color-bg:             #f7f5f5;
  --color-surface:        #faf8f8;
  --color-surface-2:      #f0ecec;
  --color-text:           #221818;
  --color-text-muted:     #5e4a4a;
  --color-border:         #e4d9d9;
  --color-green-light:    #e8c4c8;
  --color-white:          #ffffff;
  --color-overlay:        rgba(110, 34, 41, 0.75);

  /* Typography */
  --font-display:  'Noto Serif TC', serif;
  --font-body:     'Noto Sans TC', sans-serif;

  /* Font Sizes (fluid) */
  --text-display: clamp(2.5rem, 5vw, 5rem);
  --text-h1:      clamp(2rem, 3.5vw, 3.5rem);
  --text-h2:      clamp(1.5rem, 2.5vw, 2.25rem);
  --text-h3:      clamp(1.125rem, 1.8vw, 1.5rem);
  --text-body:    clamp(1rem, 0.5vw, 1.125rem);
  --text-small:   0.875rem;
  --text-label:   0.75rem;

  /* Spacing (8px base) */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Border Radius */
  --radius-sm:   0.25rem;
  --radius-md:   0.5rem;
  --radius-lg:   0.75rem;
  --radius-xl:   1rem;
  --radius-2xl:  1.5rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm:  0 2px 8px rgba(26,34,24,0.08);
  --shadow-md:  0 4px 16px rgba(26,34,24,0.12);
  --shadow-lg:  0 12px 40px rgba(26,34,24,0.15);
  --shadow-xl:  0 24px 64px rgba(26,34,24,0.18);

  /* Transitions */
  --ease:       cubic-bezier(0.16, 1, 0.3, 1);
  --duration:   180ms;
  --duration-md: 300ms;
  --duration-lg: 500ms;

  /* Layout */
  --container:  1200px;
  --nav-height: 64px;
}

/* Dark Mode */
[data-theme="dark"] {
  --color-primary:      #D96A76;
  --color-primary-hover:#E8808A;
  --color-primary-dark: #8B3A44;
  --color-accent:       #e8a030;
  --color-bg:           #1a1010;
  --color-surface:      #241818;
  --color-surface-2:    #2e1f1f;
  --color-text:         #dcd1d1;
  --color-text-muted:   #9e8787;
  --color-border:       #3d2727;
  --color-green-light:  #402828;
  --color-overlay:      rgba(30, 10, 10, 0.82);
}

/* ── Reset & Base ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-body);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  transition: background-color var(--duration-md) var(--ease),
              color var(--duration-md) var(--ease);
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

a { color: inherit; text-decoration: none; }

ul, ol { list-style: none; }

/* ── Typography ── */
.font-display { font-family: var(--font-display); }

h1, h2, h3, .h1, .h2, .h3 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.25;
  color: var(--color-text);
}

h1 { font-size: var(--text-h1); }
h2 { font-size: var(--text-h2); }
h3 { font-size: var(--text-h3); }

.text-display { font-size: var(--text-display); font-family: var(--font-display); font-weight: 700; line-height: 1.1; }
.text-muted    { color: var(--color-text-muted); }
.text-accent   { color: var(--color-accent); }
.text-primary  { color: var(--color-primary); }
.text-center   { text-align: center; }
.text-small    { font-size: var(--text-small); }
.text-label    { font-size: var(--text-label); font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; }

/* ── Layout ── */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.section {
  padding-block: var(--space-20);
}

.section-sm { padding-block: var(--space-12); }

.section-header {
  text-align: center;
  margin-bottom: var(--space-12);
}

.section-label {
  display: inline-block;
  font-size: var(--text-label);
  color: var(--color-accent);
  font-family: var(--font-body);
  font-weight: 700;
  letter-spacing: 0.1em;
  margin-bottom: var(--space-3);
}

.section-title {
  font-size: var(--text-h2);
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-4);
}

.section-desc {
  font-size: var(--text-body);
  color: var(--color-text-muted);
  max-width: 640px;
  margin-inline: auto;
  line-height: 1.8;
}

/* Grid helpers */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-8); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-8); }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-6); }

/* Flex helpers */
.flex         { display: flex; }
.flex-center  { display: flex; align-items: center; justify-content: center; }
.flex-between { display: flex; align-items: center; justify-content: space-between; }
.flex-col     { display: flex; flex-direction: column; }
.gap-2  { gap: var(--space-2); }
.gap-4  { gap: var(--space-4); }
.gap-6  { gap: var(--space-6); }
.gap-8  { gap: var(--space-8); }

/* ── Navigation ── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background-color: rgba(245, 247, 244, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: background-color var(--duration-md) var(--ease),
              border-color var(--duration-md) var(--ease);
}

[data-theme="dark"] .nav {
  background-color: rgba(17, 26, 16, 0.88);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-logo {
  display: flex;
  flex-direction: column;
  gap: 1px;
  text-decoration: none;
}

.nav-logo-en {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--logo-en-color, #B53845);
  letter-spacing: 0.02em;
  line-height: 1.2;
}

.nav-logo-zh {
  font-size: var(--text-small);
  font-weight: 600;
  color: var(--logo-zh-color, #C94855);
  line-height: 1.2;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.nav-link {
  font-size: var(--text-small);
  font-weight: 500;
  color: var(--color-text);
  position: relative;
  padding-bottom: 2px;
  transition: color var(--duration) var(--ease);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-primary);
  transition: width var(--duration-md) var(--ease);
}

.nav-link:hover { color: var(--color-primary); }
.nav-link:hover::after,
.nav-link.active::after { width: 100%; }
.nav-link.active { color: var(--color-primary); font-weight: 700; }

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* Theme Toggle */
.theme-toggle {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--duration) var(--ease);
  color: var(--color-text-muted);
}

.theme-toggle:hover {
  background: var(--color-green-light);
  color: var(--color-primary);
  border-color: var(--color-primary);
}

/* Mobile menu toggle */
.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: var(--space-2);
  background: none;
  border: none;
}

.nav-hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: var(--radius-full);
  transition: all var(--duration-md) var(--ease);
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.75rem 1.5rem;
  font-family: var(--font-body);
  font-size: var(--text-small);
  font-weight: 700;
  border-radius: var(--radius-full);
  border: 2px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--duration) var(--ease);
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-white);
  border-color: var(--color-primary);
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-accent {
  background-color: var(--color-accent);
  color: var(--color-white);
  border-color: var(--color-accent);
}

.btn-accent:hover {
  background-color: var(--color-accent-hover);
  border-color: var(--color-accent-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(200,133,10,0.35);
}

.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background-color: var(--color-primary);
  color: var(--color-white);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-outline-white {
  background-color: transparent;
  color: var(--color-white);
  border-color: rgba(255,255,255,0.6);
}

.btn-outline-white:hover {
  background-color: rgba(255,255,255,0.15);
  border-color: var(--color-white);
  transform: translateY(-2px);
}

.btn-lg {
  padding: 1rem 2rem;
  font-size: 1rem;
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: var(--text-label);
}

/* ── Cards ── */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  transition: transform var(--duration-md) var(--ease),
              box-shadow var(--duration-md) var(--ease),
              border-color var(--duration-md) var(--ease);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-green-light);
}

.card-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-lg);
  background: var(--color-green-light);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-5);
  color: var(--color-primary);
}

.card-title {
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: var(--space-3);
  color: var(--color-text);
}

.card-desc {
  font-size: var(--text-small);
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* ── Stat / Badge ── */
.stat-item { text-align: center; }

.stat-number {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3.5rem);
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
}

.stat-label {
  font-size: var(--text-small);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-full);
  font-size: var(--text-label);
  font-weight: 700;
  background: var(--color-green-light);
  color: var(--color-primary);
}

[data-theme="dark"] .badge {
  background: var(--color-primary-dark);
  color: var(--color-primary);
}

/* ── Forms ── */
.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-label {
  font-size: var(--text-small);
  font-weight: 700;
  color: var(--color-text);
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  font-family: var(--font-body);
  font-size: var(--text-small);
  color: var(--color-text);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  outline: none;
  transition: border-color var(--duration) var(--ease),
              box-shadow var(--duration) var(--ease);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(26,92,46,0.15);
}

.form-input.is-invalid,
.form-select.is-invalid,
.form-textarea.is-invalid {
  border-color: #b53845;
  box-shadow: 0 0 0 3px rgba(181, 56, 69, 0.2);
}

.form-field-error,
.form-validation-summary {
  margin-top: var(--space-2);
  margin-bottom: 0;
  font-size: var(--text-small);
  line-height: 1.5;
  color: #b53845;
  font-weight: 600;
}

.form-validation-summary {
  margin-bottom: var(--space-4);
  padding: var(--space-3) var(--space-4);
  background: rgba(181, 56, 69, 0.08);
  border: 1px solid rgba(181, 56, 69, 0.25);
  border-radius: var(--radius-md);
}

.form-textarea { resize: vertical; min-height: 140px; }

/* ── Hero ── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: var(--color-primary-dark);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, #8B2E38 50%, var(--color-primary) 100%);
}

.hero-pattern {
  position: absolute;
  inset: 0;
  opacity: 0.06;
  background-image: radial-gradient(circle at 1px 1px, rgba(255,255,255,0.6) 1px, transparent 0);
  background-size: 40px 40px;
}

.hero-content {
  position: relative;
  z-index: 2;
  color: var(--color-white);
  max-width: 800px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.25);
  border-radius: var(--radius-full);
  font-size: var(--text-small);
  color: rgba(255,255,255,0.9);
  margin-bottom: var(--space-6);
}

.hero-title {
  font-size: var(--text-display);
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.1;
  color: var(--color-white);
  margin-bottom: var(--space-6);
}

.hero-title .accent { color: var(--color-accent); }

.hero-desc {
  font-size: clamp(1rem, 1.5vw, 1.25rem);
  color: rgba(255,255,255,0.8);
  line-height: 1.7;
  margin-bottom: var(--space-8);
  max-width: 560px;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}

/* ── Section variants ── */
.bg-surface  { background-color: var(--color-surface); }
.bg-surface-2{ background-color: var(--color-surface-2); }
.bg-primary  {
  background: linear-gradient(135deg, var(--color-primary-dark), var(--color-primary));
  color: var(--color-white);
}
.bg-primary h2,
.bg-primary h3,
.bg-primary .section-title { color: var(--color-white); }
.bg-primary .section-desc,
.bg-primary .text-muted      { color: rgba(255,255,255,0.75); }
.bg-primary .section-label   { color: var(--color-accent); }

/* ── Reveal animation ── */
.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity var(--duration-lg) var(--ease),
              transform var(--duration-lg) var(--ease);
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 100ms; }
.reveal-delay-2 { transition-delay: 200ms; }
.reveal-delay-3 { transition-delay: 300ms; }
.reveal-delay-4 { transition-delay: 400ms; }

/* ── Accordion (FAQ) ── */
.accordion-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: var(--space-3);
  transition: border-color var(--duration) var(--ease);
}

.accordion-item.open { border-color: var(--color-primary); }

.accordion-trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-5) var(--space-6);
  background: var(--color-surface);
  border: none;
  cursor: pointer;
  text-align: left;
  font-family: var(--font-body);
  font-size: var(--text-small);
  font-weight: 700;
  color: var(--color-text);
  transition: background var(--duration) var(--ease);
}

.accordion-trigger:hover { background: var(--color-surface-2); }

.accordion-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  color: var(--color-primary);
  transition: transform var(--duration-md) var(--ease);
}

.accordion-item.open .accordion-icon { transform: rotate(180deg); }

.accordion-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--duration-md) var(--ease);
}

.accordion-body.open { max-height: none; }

.accordion-content {
  padding: var(--space-4) var(--space-6) var(--space-5);
  font-size: var(--text-small);
  color: var(--color-text-muted);
  line-height: 1.8;
  border-top: 1px solid var(--color-border);
}

/* ── Steps / Timeline ── */
.steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-6);
  position: relative;
}

.steps::before {
  content: '';
  position: absolute;
  top: 28px;
  left: calc(12.5% + 28px);
  right: calc(12.5% + 28px);
  height: 2px;
  background: var(--color-border);
}

.step { text-align: center; position: relative; }

.step-num {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  color: var(--color-white);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--space-4);
  position: relative;
  z-index: 1;
}

.step-title {
  font-weight: 700;
  font-size: var(--text-small);
  margin-bottom: var(--space-2);
}

.step-desc {
  font-size: var(--text-label);
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ── Breadcrumb ── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-small);
  color: var(--color-text-muted);
  padding-block: var(--space-4);
}

.breadcrumb a:hover { color: var(--color-primary); }

.breadcrumb-sep { opacity: 0.4; }

/* ── Page hero (sub-pages) ── */
.page-hero {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  color: var(--color-white);
  padding-block: var(--space-16) var(--space-12);
  text-align: center;
}

.page-hero-title {
  font-size: var(--text-h1);
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: var(--space-4);
}

.page-hero-desc {
  font-size: clamp(1rem, 1.5vw, 1.2rem);
  color: rgba(255,255,255,0.8);
  max-width: 560px;
  margin-inline: auto;
}

/* ── Social float stack (WhatsApp, Facebook, Instagram, Carousell) ── */
.social-float-stack {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 999;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.social-float-btn {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.22);
  transition: transform var(--duration) var(--ease), box-shadow var(--duration) var(--ease);
}

.social-float-btn:hover {
  transform: scale(1.1);
}

.social-float-fb {
  background: #1877f2;
  box-shadow: 0 4px 20px rgba(24, 119, 242, 0.45);
}

.social-float-fb:hover {
  box-shadow: 0 8px 28px rgba(24, 119, 242, 0.55);
}

.social-float-ig {
  background: linear-gradient(135deg, #f09433 0%, #e6683c 25%, #dc2743 50%, #cc2366 75%, #bc1888 100%);
  box-shadow: 0 4px 20px rgba(220, 39, 67, 0.4);
}

.social-float-ig:hover {
  box-shadow: 0 8px 28px rgba(220, 39, 67, 0.5);
}

.social-float-carousell {
  background: #ff6633;
  box-shadow: 0 4px 20px rgba(255, 102, 51, 0.45);
}

.social-float-carousell:hover {
  box-shadow: 0 8px 28px rgba(255, 102, 51, 0.55);
}

.social-float-wa {
  background: #25D366;
  box-shadow: 0 4px 20px rgba(37, 211, 102, 0.45);
}

.social-float-wa:hover {
  box-shadow: 0 8px 32px rgba(37, 211, 102, 0.55);
}

@media (max-width: 600px) {
  .social-float-stack {
    bottom: 16px;
    right: 16px;
    gap: 10px;
  }
  .social-float-btn {
    width: 50px;
    height: 50px;
  }
  .social-float-btn svg {
    width: 24px;
    height: 24px;
  }
}

/* Legacy single WhatsApp button — kept for reference */
.wa-float {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 999;
  width: 56px;
  height: 56px;
  border-radius: var(--radius-full);
  background: #25D366;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 20px rgba(37, 211, 102, 0.45);
  transition: transform var(--duration) var(--ease), box-shadow var(--duration) var(--ease);
}

.wa-float:hover {
  transform: scale(1.1);
  box-shadow: 0 8px 32px rgba(37, 211, 102, 0.55);
}

/* ── Footer ── */
.footer {
  background: var(--color-primary-dark);
  color: rgba(255,255,255,0.75);
  padding-block: var(--space-16) var(--space-8);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-8);
  margin-bottom: var(--space-12);
}

.footer-logo-en {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: var(--space-2);
}

.footer-logo-zh { font-size: var(--text-small); margin-bottom: var(--space-4); }
.footer-tagline { font-size: var(--text-small); line-height: 1.7; }

.footer-heading {
  font-size: var(--text-small);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: var(--space-5);
}

.footer-links { display: flex; flex-direction: column; gap: var(--space-3); }

.footer-link {
  font-size: var(--text-small);
  color: rgba(255,255,255,0.65);
  transition: color var(--duration) var(--ease);
}

.footer-link:hover { color: var(--color-white); }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
  font-size: var(--text-small);
}

/* ── Responsive ── */
@media (max-width: 900px) {
  :root { --nav-height: 56px; }

  .nav-actions > .btn-primary.btn-sm { display: none; }

  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }

  .steps {
    grid-template-columns: repeat(2, 1fr);
  }

  .steps::before { display: none; }

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

  .nav-links { display: none; }
  .nav-hamburger {
    display: flex;
    min-width: 44px;
    min-height: 44px;
    padding: 10px;
  }
}

@media (max-width: 600px) {
  .container { padding-inline: var(--space-4); }
  .section   { padding-block: var(--space-12); }

  :root {
    --text-small: 0.9375rem;
    --text-label: 0.8125rem;
  }

  .form-input,
  .form-select,
  .form-textarea {
    font-size: 1rem;
  }

  .grid-2,
  .grid-3,
  .grid-4 { grid-template-columns: 1fr; }

  .steps { grid-template-columns: 1fr; }

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

  .hero-cta { flex-direction: column; }

  .footer-bottom { flex-direction: column; text-align: center; }
}

/* Mobile nav overlay */
.nav-mobile {
  position: fixed;
  inset: var(--nav-height) 0 0 0;
  background: var(--color-bg);
  z-index: 99;
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  transform: translateX(100%);
  transition: transform var(--duration-md) var(--ease);
  visibility: hidden;
  pointer-events: none;
  overflow-y: auto;
}

.nav-mobile.open {
  transform: translateX(0);
  visibility: visible;
  pointer-events: auto;
}

.nav-mobile .nav-link {
  font-size: 1.1rem;
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border);
}

/* ── Utilities ── */
.hidden { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; }
.mt-4  { margin-top: var(--space-4); }
.mt-6  { margin-top: var(--space-6); }
.mt-8  { margin-top: var(--space-8); }
.mb-4  { margin-bottom: var(--space-4); }
.mb-6  { margin-bottom: var(--space-6); }
.mb-8  { margin-bottom: var(--space-8); }
.w-full { width: 100%; }