/* ═══════════════════════════════════════════════════════════════════════════
   FitCalc — Design System
   1. Tokens  2. Reset  3. Typography  4. Layout  5. Nav  6. Hero
   7. Cards   8. Forms  9. Tables  10. FAQ  11. Breadcrumbs  12. Footer
   13. Charts 14. Pages 15. Utilities 16. Responsive
   ═══════════════════════════════════════════════════════════════════════════ */

/* ── 1. Design Tokens ─────────────────────────────────────────────────────── */

:root {
  /* Background */
  --bg-base:    #0B1120;
  --bg-surface: #111827;
  --bg-card:    #1E293B;
  --bg-card-hover: #263348;
  --bg-input:   #0F172A;

  /* Primary — lime green */
  --primary:        #A3E635;
  --primary-hover:  #BEF264;
  --primary-dim:    #65A30D;
  --primary-bg:     rgba(163, 230, 53, 0.08);

  /* Blueprint palette */
  --blue:   #3B82F6;
  --green:  #22C55E;
  --orange: #F59E0B;
  --red:    #EF4444;
  --purple: #8B5CF6;
  --cyan:   #06B6D4;
  --pink:   #EC4899;

  /* Macros */
  --macro-protein: #EF4444;
  --macro-carbs:   #3B82F6;
  --macro-fat:     #F59E0B;

  /* Text */
  --text:       #F1F5F9;
  --text-dim:   #94A3B8;
  --text-muted: #64748B;

  /* Borders */
  --border:      #1E293B;
  --border-hover:#334155;

  /* Radius */
  --radius-sm: 6px;
  --radius:    10px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* Shadows */
  --shadow-sm:  0 1px 2px rgba(0,0,0,.3);
  --shadow:     0 4px 12px rgba(0,0,0,.4);
  --shadow-lg:  0 8px 30px rgba(0,0,0,.5);
  --shadow-glow:0 0 20px rgba(163,230,53,.15);

  /* Transitions */
  --ease: cubic-bezier(.4,0,.2,1);

  /* Container */
  --container: 1200px;

  /* Font families */
  --font-body: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

/* ── 2. Reset ─────────────────────────────────────────────────────────────── */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  font-weight: 400;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg-base);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
}

img, svg { display: block; max-width: 100%; }
a { color: var(--primary); text-decoration: none; transition: color .2s var(--ease); }
a:hover { color: var(--primary-hover); }
ul, ol { list-style: none; }
button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; }
h1, h2, h3, h4, h5, h6 { line-height: 1.25; font-weight: 700; color: var(--text); }

/* ── 3. Typography ────────────────────────────────────────────────────────── */

h1 { font-size: 2.75rem; letter-spacing: -0.03em; }
h2 { font-size: 2rem;    letter-spacing: -0.02em; }
h3 { font-size: 1.5rem;  letter-spacing: -0.01em; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1rem;    }
h6 { font-size: 0.875rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--text-dim); }

p { margin-bottom: 1rem; color: var(--text-dim); }

.text-mono { font-family: var(--font-mono); }
.text-primary { color: var(--primary); }
.text-sm { font-size: 0.875rem; }
.text-xs { font-size: 0.75rem; }
.text-lg { font-size: 1.125rem; }
.text-xl { font-size: 1.25rem; }

.result-value {
  font-family: var(--font-mono);
  font-size: 3rem;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
}

.result-unit {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 400;
  color: var(--text-dim);
  margin-left: 0.25rem;
}

/* ── 4. Layout ────────────────────────────────────────────────────────────── */

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section { padding: 4rem 0; }
.section--sm { padding: 2rem 0; }

.grid {
  display: grid;
  gap: 1.5rem;
}
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
.grid--auto { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }

.flex { display: flex; }
.flex--center { align-items: center; justify-content: center; }
.flex--between { align-items: center; justify-content: space-between; }
.flex--col { flex-direction: column; }
.flex--wrap { flex-wrap: wrap; }
.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.gap-3 { gap: 1.5rem; }
.gap-4 { gap: 2rem; }

/* ── 5. Navigation ────────────────────────────────────────────────────────── */

.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(11, 17, 32, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  height: 64px;
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.nav__logo {
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav__logo span { color: var(--primary); }

.nav__links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.nav__link {
  padding: 0.5rem 0.875rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-dim);
  border-radius: var(--radius-sm);
  transition: color .2s var(--ease), background .2s var(--ease);
}

.nav__link:hover,
.nav__link--active {
  color: var(--text);
  background: var(--primary-bg);
}

.nav__link--active { color: var(--primary); }

.nav__cta {
  margin-left: 0.5rem;
}

/* Hamburger */
.nav__hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: 4px;
  cursor: pointer;
}

.nav__hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 1px;
  transition: transform .3s var(--ease), opacity .3s var(--ease);
}

.nav__hamburger.is-open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav__hamburger.is-open span:nth-child(2) { opacity: 0; }
.nav__hamburger.is-open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav__mobile {
  display: none;
  position: fixed;
  top: 64px; left: 0; right: 0;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  padding: 1rem;
  flex-direction: column;
  gap: 0.25rem;
}

.nav__mobile.is-open { display: flex; }

.nav__mobile .nav__link {
  padding: 0.75rem 1rem;
  font-size: 1rem;
}

/* ── 6. Hero ──────────────────────────────────────────────────────────────── */

.hero {
  position: relative;
  padding: 10rem 0 6rem;
  overflow: hidden;
  margin-top: 64px;
}

.hero__bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0.15;
}

.hero__overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 0%, var(--bg-base) 100%);
}

.hero__content {
  position: relative;
  z-index: 1;
  max-width: 720px;
}

.hero__title {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  margin-bottom: 1.25rem;
  line-height: 1.1;
}

.hero__title span { color: var(--primary); }

.hero__subtitle {
  font-size: 1.25rem;
  color: var(--text-dim);
  margin-bottom: 2rem;
  max-width: 560px;
}

/* ── 7. Cards ─────────────────────────────────────────────────────────────── */

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: border-color .2s var(--ease), box-shadow .2s var(--ease), transform .2s var(--ease);
}

.card:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow);
}

.card--link {
  display: block;
  color: inherit;
  text-decoration: none;
}

.card--link:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-dim);
  color: inherit;
}

.card__icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius);
  background: var(--primary-bg);
  margin-bottom: 1rem;
  font-size: 1.5rem;
}

.card__title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.card__desc {
  font-size: 0.875rem;
  color: var(--text-dim);
  margin-bottom: 0;
}

/* Calculator card */
.calc-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.calc-card__header {
  padding: 1.5rem 1.5rem 0;
}

.calc-card__title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.calc-card__subtitle {
  font-size: 0.875rem;
  color: var(--text-dim);
  margin-bottom: 0;
}

.calc-card__form {
  padding: 1.5rem;
}

.calc-card__result {
  padding: 1.5rem;
  background: var(--bg-surface);
  border-top: 1px solid var(--border);
  display: none;
}

.calc-card__result.is-visible { display: block; }

.calc-card__chart {
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: center;
}

/* ── 8. Forms ─────────────────────────────────────────────────────────────── */

.form-group {
  margin-bottom: 1.25rem;
}

.form-label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-dim);
  margin-bottom: 0.5rem;
  cursor: pointer;
}

.form-input,
.form-select {
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 1rem;
  transition: border-color .2s var(--ease), box-shadow .2s var(--ease);
  cursor: text;
}

.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(163, 230, 53, 0.15);
}

.form-input::placeholder { color: var(--text-muted); }

.form-select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' fill='none' stroke='%2394A3B8' stroke-width='2'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 2.5rem;
  cursor: pointer;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-row--3 {
  grid-template-columns: 1fr 1fr 1fr;
}

.form-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.375rem;
}

/* Radio / toggle group */
.toggle-group {
  display: flex;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.toggle-group__option {
  flex: 1;
  padding: 0.625rem 1rem;
  text-align: center;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-dim);
  background: transparent;
  border: none;
  border-right: 1px solid var(--border);
  cursor: pointer;
  transition: background .2s var(--ease), color .2s var(--ease);
}

.toggle-group__option:last-child { border-right: none; }

.toggle-group__option:hover { color: var(--text); }

.toggle-group__option.is-active {
  background: var(--primary);
  color: var(--bg-base);
  font-weight: 600;
}

/* hidden radio inputs */
.toggle-group input[type="radio"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  font-size: 0.9375rem;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background .2s var(--ease), transform .1s var(--ease), box-shadow .2s var(--ease);
  white-space: nowrap;
}

.btn:active { transform: scale(0.98); }

.btn--primary {
  background: var(--primary);
  color: var(--bg-base);
}

.btn--primary:hover {
  background: var(--primary-hover);
  box-shadow: var(--shadow-glow);
  color: var(--bg-base);
}

.btn--secondary {
  background: var(--bg-card);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn--secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-hover);
  color: var(--text);
}

.btn--outline {
  background: transparent;
  color: var(--primary);
  border: 1px solid var(--primary-dim);
}

.btn--outline:hover {
  background: var(--primary-bg);
}

.btn--sm { padding: 0.5rem 1rem; font-size: 0.8125rem; }
.btn--lg { padding: 1rem 2rem; font-size: 1.0625rem; }
.btn--block { width: 100%; }

/* Unit toggle */
.unit-toggle {
  display: flex;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  font-size: 0.8125rem;
}

.unit-toggle__btn {
  padding: 0.375rem 0.75rem;
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-weight: 500;
  cursor: pointer;
  transition: background .15s var(--ease), color .15s var(--ease);
}

.unit-toggle__btn.is-active {
  background: var(--primary);
  color: var(--bg-base);
  font-weight: 600;
}

/* ── 9. Tables ────────────────────────────────────────────────────────────── */

.nutrition-table {
  width: 100%;
  border-collapse: collapse;
}

.nutrition-table th,
.nutrition-table td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 0.875rem;
}

.nutrition-table th {
  color: var(--text-dim);
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.nutrition-table td { color: var(--text); }

.nutrition-table tr:hover td {
  background: rgba(163, 230, 53, 0.03);
}

.nutrition-table .text-right { text-align: right; }

.nutrition-table__highlight {
  font-weight: 700;
  font-family: var(--font-mono);
}

/* ── 10. FAQ Accordion ────────────────────────────────────────────────────── */

.faq { margin: 2rem 0; }

.faq__item {
  border-bottom: 1px solid var(--border);
}

.faq__question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.125rem 0;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  transition: color .2s var(--ease);
}

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

.faq__icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  position: relative;
  margin-left: 1rem;
}

.faq__icon::before,
.faq__icon::after {
  content: '';
  position: absolute;
  background: var(--text-dim);
  transition: transform .3s var(--ease);
}

.faq__icon::before {
  top: 50%; left: 3px;
  width: 14px; height: 2px;
  transform: translateY(-50%);
}

.faq__icon::after {
  top: 3px; left: 50%;
  width: 2px; height: 14px;
  transform: translateX(-50%);
}

.faq__item.is-open .faq__icon::after {
  transform: translateX(-50%) rotate(90deg);
}

.faq__answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height .35s var(--ease), padding .35s var(--ease);
}

.faq__answer__inner {
  padding: 0 0 1.25rem;
  color: var(--text-dim);
  font-size: 0.9375rem;
  line-height: 1.7;
}

.faq__item.is-open .faq__answer {
  max-height: 800px;
}

/* ── 11. Breadcrumbs ──────────────────────────────────────────────────────── */

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 1rem 0;
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-top: 64px;
}

.breadcrumb__sep { color: var(--text-muted); }

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

/* ── 12. Footer ───────────────────────────────────────────────────────────── */

.footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border);
  padding: 3rem 0 2rem;
  margin-top: 4rem;
}

.footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
}

.footer__brand {
  font-weight: 800;
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

.footer__brand span { color: var(--primary); }

.footer__desc {
  font-size: 0.875rem;
  color: var(--text-dim);
  max-width: 320px;
  line-height: 1.6;
}

.footer__heading {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-bottom: 1rem;
}

.footer__link {
  display: block;
  font-size: 0.875rem;
  color: var(--text-dim);
  padding: 0.25rem 0;
  transition: color .2s var(--ease);
}

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

.footer__bottom {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-size: 0.8125rem;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* ── 13. Charts ───────────────────────────────────────────────────────────── */

.fit-chart { max-width: 100%; height: auto; }

.chart-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 0.75rem;
  justify-content: center;
}

.chart-legend__item {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.8125rem;
  color: var(--text-dim);
}

.chart-legend__dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* ── 14. Page-specific styles ─────────────────────────────────────────────── */

/* Homepage calculator grid */
.calc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.25rem;
}

/* Content sections */
.content-section {
  padding: 3rem 0;
}

.content-section h2 {
  margin-bottom: 1rem;
}

.content-section p {
  max-width: 75ch;
  margin-bottom: 1rem;
}

.content-section ul,
.content-section ol {
  list-style: disc;
  padding-left: 1.5rem;
  margin-bottom: 1rem;
  color: var(--text-dim);
}

.content-section ol { list-style: decimal; }

.content-section li {
  margin-bottom: 0.5rem;
  font-size: 0.9375rem;
  line-height: 1.7;
}

.content-section strong { color: var(--text); font-weight: 600; }

/* Food / Activity / Exercise pages */
.page-header {
  padding: 6rem 0 3rem;
  margin-top: 64px;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
}

.page-header__title {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

.page-header__meta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  font-size: 0.875rem;
  color: var(--text-dim);
}

/* Badge */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.625rem;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 9999px;
  background: var(--primary-bg);
  color: var(--primary);
  border: 1px solid rgba(163, 230, 53, 0.2);
}

.badge--blue   { background: rgba(59,130,246,.1);  color: var(--blue);   border-color: rgba(59,130,246,.2); }
.badge--green  { background: rgba(34,197,94,.1);   color: var(--green);  border-color: rgba(34,197,94,.2); }
.badge--orange { background: rgba(245,158,11,.1);  color: var(--orange); border-color: rgba(245,158,11,.2); }
.badge--red    { background: rgba(239,68,68,.1);   color: var(--red);    border-color: rgba(239,68,68,.2); }
.badge--purple { background: rgba(139,92,246,.1);  color: var(--purple); border-color: rgba(139,92,246,.2); }

/* Nutrition info box */
.nutrition-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin: 1.5rem 0;
}

.nutrition-box__title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--primary);
}

.nutrition-box__row {
  display: flex;
  justify-content: space-between;
  padding: 0.5rem 0;
  font-size: 0.9375rem;
  border-bottom: 1px solid var(--border);
}

.nutrition-box__row:last-child { border-bottom: none; }

.nutrition-box__value {
  font-family: var(--font-mono);
  font-weight: 600;
}

/* Related items grid */
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

/* Guide pages */
.guide-content {
  max-width: 75ch;
  margin: 0 auto;
}

.guide-content h2 { margin-top: 2.5rem; margin-bottom: 1rem; }
.guide-content h3 { margin-top: 2rem; margin-bottom: 0.75rem; }

/* ── 15. Utilities ────────────────────────────────────────────────────────── */

.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

.hidden { display: none !important; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mx-auto { margin-left: auto; margin-right: auto; }
.text-center { text-align: center; }

.warning-box {
  padding: 1rem 1.25rem;
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.3);
  border-radius: var(--radius-sm);
  color: var(--orange);
  font-size: 0.875rem;
  margin: 1rem 0;
}

.info-box {
  padding: 1rem 1.25rem;
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.3);
  border-radius: var(--radius-sm);
  color: var(--blue);
  font-size: 0.875rem;
  margin: 1rem 0;
}

.noscript-msg {
  padding: 2rem;
  text-align: center;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 2rem 0;
}

/* ── 16. Responsive ───────────────────────────────────────────────────────── */

@media (max-width: 1024px) {
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .footer__grid { grid-template-columns: 1fr 1fr; }
  h1, .hero__title { font-size: 2.5rem; }
}

@media (max-width: 640px) {
  .nav__links { display: none; }
  .nav__cta   { display: none; }
  .nav__hamburger { display: flex; }

  h1, .hero__title { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  .hero { padding: 7rem 0 3rem; }
  .hero__subtitle { font-size: 1rem; }
  .result-value { font-size: 2.25rem; }

  .container { padding: 0 1rem; }
  .section { padding: 2.5rem 0; }

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

  .breadcrumb { font-size: 0.75rem; }
  .page-header { padding: 4rem 0 2rem; }
  .page-header__title { font-size: 1.75rem; }
}

@media (max-width: 400px) {
  html { font-size: 15px; }
  .hero__title { font-size: 1.75rem; }
  .card { padding: 1rem; }
  .calc-card__form { padding: 1rem; }
  .calc-card__result { padding: 1rem; }
}