/* ==========================================================================
   HomeLogic — Design System
   Editorial-meets-tool. Architectural Digest meets Notion.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Design Tokens
   -------------------------------------------------------------------------- */
:root {
  /* Color Palette */
  --color-primary: #1B4332;          /* deep forest */
  --color-primary-700: #143527;
  --color-primary-300: #6B8E7A;
  --color-primary-100: #D8E8DE;

  --color-accent: #E76F51;           /* burnt sienna */
  --color-accent-700: #C9593D;
  --color-accent-100: #FBE3DC;

  --color-bg: #F8F9FA;               /* cool off-white */
  --color-surface: #FFFFFF;
  --color-surface-alt: #FCFCFD;

  --color-text: #212529;             /* charcoal */
  --color-text-secondary: #6C757D;   /* slate */
  --color-text-muted: #ADB5BD;

  --color-success-bg: #D8F3DC;       /* soft mint */
  --color-success-text: #1F5130;
  --color-success-border: #B7E4C7;

  --color-warning-text: #8A5A00;
  --color-warning-bg: #FFF3CD;
  --color-warning-border: #FFE69C;

  --color-error-text: #842029;
  --color-error-bg: #FDE2E4;
  --color-error-border: #F8B4BA;

  --color-border: #DEE2E6;
  --color-border-soft: #E9ECEF;
  --color-input-border: #CED4DA;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

  /* Type scale */
  --fs-h1: 2.5rem;     /* 40px */
  --fs-h2: 1.75rem;    /* 28px */
  --fs-h3: 1.25rem;    /* 20px */
  --fs-body: 1rem;     /* 16px */
  --fs-small: 0.875rem;
  --fs-micro: 0.75rem;

  /* Spacing — 4px grid */
  --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;

  /* Radii */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-full: 999px;

  /* Shadows */
  --shadow-card: 0 4px 12px rgba(0, 0, 0, 0.04);
  --shadow-card-hover: 0 12px 32px rgba(0, 0, 0, 0.08);
  --shadow-focus: 0 0 0 3px rgba(27, 67, 50, 0.20);
  --shadow-accent-focus: 0 0 0 3px rgba(231, 111, 81, 0.25);

  /* Layout */
  --content-width: 780px;
  --wide-width: 1140px;
  --header-height: 72px;

  /* Motion */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-standard: cubic-bezier(0.4, 0, 0.2, 1);
  --dur-fast: 150ms;
  --dur: 250ms;
  --dur-slow: 400ms;
}

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

/* If JS is disabled, force all .fade-in elements visible so content is
   not trapped at opacity: 0. The .js-ready class is added by main.js on boot. */
.fade-in { opacity: 0; transform: translateY(12px); }
.no-js .fade-in,
.fade-in.is-visible { opacity: 1; transform: translateY(0); }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: calc(var(--header-height) + 16px);
}

body {
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: 1.65;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: 'cv11', 'ss01';
  min-height: 100vh;
}

img, svg { max-width: 100%; display: block; }

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease-standard);
}
a:hover { color: var(--color-accent); }

button { font-family: inherit; cursor: pointer; border: none; background: none; }

ul, ol { list-style: none; }

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 4px;
}

.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;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: 16px;
  background: var(--color-primary);
  color: #fff;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  z-index: 2000;
  font-weight: 600;
}
.skip-link:focus { top: 16px; color: #fff; }

/* --------------------------------------------------------------------------
   3. Typography
   -------------------------------------------------------------------------- */
h1, h2, h3, h4 {
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--color-text);
}

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

p { color: var(--color-text); }
p + p { margin-top: var(--space-4); }

.lead {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.eyebrow {
  font-size: var(--fs-micro);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--color-accent);
  margin-bottom: var(--space-3);
  display: block;
}

.text-secondary { color: var(--color-text-secondary); }
.text-center { text-align: center; }

/* --------------------------------------------------------------------------
   4. Layout
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 0 24px;
}

.container-narrow {
  width: 100%;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 80px 0;
  min-height: 320px;
}
.section--tight { padding: 56px 0; }
.section--alt { background: var(--color-surface); border-top: 1px solid var(--color-border-soft); }

.section-gap { height: 64px; }

/* --------------------------------------------------------------------------
   5. Header & Navigation
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(248, 249, 250, 0.85);
  backdrop-filter: blur(12px) saturate(180%);
  -webkit-backdrop-filter: blur(12px) saturate(180%);
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease-standard),
              background var(--dur) var(--ease-standard),
              box-shadow var(--dur) var(--ease-standard);
}
.site-header.is-scrolled {
  background: rgba(255, 255, 255, 0.92);
  border-bottom-color: var(--color-border-soft);
  box-shadow: 0 1px 0 rgba(0,0,0,0.02);
}

.header-inner {
  height: var(--header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
  color: var(--color-text);
}
.brand:hover { color: var(--color-text); }
.brand-mark {
  width: 32px; height: 32px;
  border-radius: 8px;
  background: var(--color-primary);
  color: #fff;
  display: grid;
  place-items: center;
  font-size: 0.95rem;
  font-weight: 800;
}
.brand-name b { color: var(--color-primary); }

.main-nav { display: flex; align-items: center; gap: var(--space-6); }
.main-nav a {
  color: var(--color-text);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 6px 2px;
  position: relative;
}
.main-nav a::after {
  content: '';
  position: absolute;
  left: 0; right: 100%;
  bottom: -2px;
  height: 2px;
  background: var(--color-accent);
  transition: right var(--dur) var(--ease-out);
}
.main-nav a:hover::after,
.main-nav a.is-active::after { right: 0; }

.header-actions { display: flex; align-items: center; gap: var(--space-4); }

/* Unit Toggle */
.unit-toggle {
  display: inline-flex;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: 4px;
  position: relative;
  box-shadow: var(--shadow-card);
}
.unit-toggle__option {
  position: relative;
  z-index: 2;
  padding: 6px 16px;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  border-radius: var(--radius-full);
  transition: color var(--dur) var(--ease-standard);
  white-space: nowrap;
}
.unit-toggle__option.is-active { color: #fff; }
.unit-toggle__option:focus-visible { outline-offset: 2px; }
.unit-toggle__slider {
  position: absolute;
  top: 4px; bottom: 4px;
  left: 4px;
  width: calc(50% - 4px);
  background: var(--color-primary);
  border-radius: var(--radius-full);
  transition: transform var(--dur) var(--ease-out);
  z-index: 1;
}
.unit-toggle[data-unit="us"] .unit-toggle__slider { transform: translateX(100%); }

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  width: 40px; height: 40px;
  border-radius: 8px;
  align-items: center;
  justify-content: center;
  color: var(--color-text);
}
.nav-toggle:hover { background: var(--color-border-soft); }
.nav-toggle svg { width: 22px; height: 22px; }

@media (max-width: 880px) {
  .nav-toggle { display: inline-flex; }
  .main-nav {
    position: fixed;
    inset: var(--header-height) 0 auto 0;
    background: var(--color-surface);
    flex-direction: column;
    align-items: stretch;
    padding: 16px 24px 24px;
    gap: 0;
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-card-hover);
    transform: translateY(-110%);
    transition: transform var(--dur) var(--ease-out);
  }
  .main-nav.is-open { transform: translateY(0); }
  .main-nav a {
    padding: 14px 4px;
    border-bottom: 1px solid var(--color-border-soft);
    font-size: 1rem;
  }
  .main-nav a:last-child { border-bottom: none; }
  .header-actions .unit-toggle { display: none; }
  .mobile-unit-row { display: flex; }
}

.mobile-unit-row {
  display: none;
  padding: 12px 24px 20px;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  justify-content: center;
}
@media (max-width: 880px) {
  .mobile-unit-row.is-visible { display: flex; }
}

/* --------------------------------------------------------------------------
   6. Hero
   -------------------------------------------------------------------------- */
.hero {
  padding: 96px 0 64px;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: -120px; right: -120px;
  width: 380px; height: 380px;
  background: radial-gradient(circle, rgba(231,111,81,0.12), transparent 70%);
  pointer-events: none;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--space-12);
  align-items: center;
}
.hero h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  letter-spacing: -0.035em;
  margin-bottom: var(--space-5);
}
.hero h1 .accent {
  position: relative;
  color: var(--color-accent);
}
.hero h1 .accent::after {
  content: '';
  position: absolute;
  left: 0; right: 0;
  bottom: 4px;
  height: 3px;
  background: var(--color-accent);
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  animation: underlineDraw 900ms var(--ease-out) 400ms forwards;
}
@keyframes underlineDraw { to { transform: scaleX(1); } }

.hero-tagline {
  font-size: 1.25rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-8);
  max-width: 540px;
}

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

.hero-visual {
  position: relative;
  aspect-ratio: 4 / 3;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--color-primary-100), #fff);
  border: 1px solid var(--color-border-soft);
  box-shadow: var(--shadow-card-hover);
  overflow: hidden;
  padding: 32px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
}
.hero-visual::before {
  content: '';
  position: absolute;
  top: 24px; left: 24px; right: 24px;
  height: 60%;
  background-image:
    linear-gradient(rgba(27,67,50,0.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(27,67,50,0.08) 1px, transparent 1px);
  background-size: 24px 24px;
  border-radius: var(--radius-md);
}
.hero-visual__card {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 20px;
  box-shadow: var(--shadow-card);
  z-index: 2;
}
.hero-visual__row {
  display: flex;
  justify-content: space-between;
  padding: 6px 0;
  font-size: 0.875rem;
}
.hero-visual__row + .hero-visual__row { border-top: 1px dashed var(--color-border-soft); }
.hero-visual__row b { color: var(--color-primary); }

@media (max-width: 880px) {
  .hero { padding: 56px 0 40px; }
  .hero-grid { grid-template-columns: 1fr; gap: var(--space-8); }
  .hero-visual { max-width: 420px; }
}

/* --------------------------------------------------------------------------
   7. Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 16px 28px;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: transform var(--dur-fast) var(--ease-standard),
              background var(--dur-fast) var(--ease-standard),
              box-shadow var(--dur-fast) var(--ease-standard),
              color var(--dur-fast) var(--ease-standard);
  text-align: center;
  white-space: nowrap;
  border: 1px solid transparent;
}
.btn:active { transform: translateY(1px) scale(0.99); }

.btn--primary {
  background: var(--color-primary);
  color: #fff;
}
.btn--primary:hover {
  background: var(--color-primary-700);
  color: #fff;
  box-shadow: 0 6px 18px rgba(27, 67, 50, 0.25);
}

.btn--accent {
  background: var(--color-accent);
  color: #fff;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.btn--accent:hover {
  background: var(--color-accent-700);
  color: #fff;
  box-shadow: 0 6px 18px rgba(231, 111, 81, 0.3);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn--ghost:hover {
  background: var(--color-surface);
  border-color: var(--color-text-secondary);
  color: var(--color-text);
}

.btn--block { width: 100%; }
.btn--sm { padding: 10px 18px; font-size: 0.875rem; }

/* --------------------------------------------------------------------------
   8. Cards
   -------------------------------------------------------------------------- */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: 24px;
  transition: transform var(--dur) var(--ease-out),
              box-shadow var(--dur) var(--ease-out),
              border-color var(--dur) var(--ease-out);
}

.calc-card {
  display: block;
  text-decoration: none;
  color: inherit;
  background: var(--color-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: 32px 28px;
  transition: transform var(--dur) var(--ease-out),
              box-shadow var(--dur) var(--ease-out),
              border-color var(--dur) var(--ease-out);
  position: relative;
  overflow: hidden;
}
.calc-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 0;
  background: var(--color-accent);
  transition: height var(--dur) var(--ease-out);
}
.calc-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--color-primary-100);
  color: inherit;
}
.calc-card:hover::before { height: 100%; }
.calc-card__icon {
  width: 56px; height: 56px;
  border-radius: var(--radius-md);
  background: var(--color-primary-100);
  color: var(--color-primary);
  display: grid;
  place-items: center;
  font-size: 1.5rem;
  margin-bottom: var(--space-5);
  transition: background var(--dur) var(--ease-out),
              color var(--dur) var(--ease-out);
}
.calc-card:hover .calc-card__icon {
  background: var(--color-accent);
  color: #fff;
}
.calc-card__title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--space-2);
  letter-spacing: -0.02em;
}
.calc-card__desc {
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
  line-height: 1.55;
}
.calc-card__arrow {
  margin-top: var(--space-5);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.875rem;
}

.calc-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
}
@media (max-width: 720px) {
  .calc-grid { grid-template-columns: 1fr; }
}

/* --------------------------------------------------------------------------
   9. Trust Bar
   -------------------------------------------------------------------------- */
.trust-bar {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-8);
  padding: 32px 0;
  border-top: 1px solid var(--color-border-soft);
  border-bottom: 1px solid var(--color-border-soft);
}
.trust-item {
  display: flex;
  align-items: center;
  gap: 14px;
  justify-content: center;
}
.trust-item__icon {
  width: 40px; height: 40px;
  border-radius: var(--radius-sm);
  background: var(--color-primary-100);
  color: var(--color-primary);
  display: grid;
  place-items: center;
  font-size: 1rem;
  flex-shrink: 0;
}
.trust-item__text { font-weight: 600; font-size: 0.9375rem; }

@media (max-width: 720px) {
  .trust-bar { grid-template-columns: 1fr; gap: var(--space-4); }
  .trust-item { justify-content: flex-start; }
}

/* --------------------------------------------------------------------------
   10. How It Works
   -------------------------------------------------------------------------- */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-8);
  position: relative;
  margin-top: var(--space-12);
}
.steps::before {
  content: '';
  position: absolute;
  top: 28px;
  left: 16.66%;
  right: 16.66%;
  height: 2px;
  background: var(--color-border);
}
.step {
  text-align: center;
  position: relative;
  background: var(--color-bg);
  padding: 0 8px;
}
.step__num {
  width: 56px; height: 56px;
  border-radius: 50%;
  background: var(--color-surface);
  border: 2px solid var(--color-primary);
  color: var(--color-primary);
  display: grid;
  place-items: center;
  margin: 0 auto var(--space-5);
  font-weight: 700;
  font-size: 1.125rem;
  position: relative;
  z-index: 2;
}
.step__title {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: var(--space-2);
}
.step__desc { color: var(--color-text-secondary); font-size: 0.9375rem; }

@media (max-width: 720px) {
  .steps { grid-template-columns: 1fr; gap: var(--space-10); }
  .steps::before { display: none; }
}

/* --------------------------------------------------------------------------
   11. Forms & Inputs
   -------------------------------------------------------------------------- */
.form-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-5);
}
.form-grid .span-2 { grid-column: span 2; }

.field { display: flex; flex-direction: column; gap: 6px; }
.field__label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 8px;
}
.field__label .unit-tag {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  background: var(--color-border-soft);
  padding: 2px 8px;
  border-radius: var(--radius-full);
  transition: background var(--dur) var(--ease-standard), color var(--dur) var(--ease-standard);
}

.input, .select {
  width: 100%;
  font-family: inherit;
  font-size: 1rem;
  color: var(--color-text);
  background: var(--color-surface);
  border: 1px solid var(--color-input-border);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  transition: border-color var(--dur-fast) var(--ease-standard),
              box-shadow var(--dur-fast) var(--ease-standard);
  -webkit-appearance: none;
  appearance: none;
}
.input::placeholder { color: var(--color-text-muted); }
.input:hover, .select:hover { border-color: var(--color-text-secondary); }
.input:focus, .select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: var(--shadow-focus);
}
.input[aria-invalid="true"] {
  border-color: var(--color-error-border);
  background: var(--color-error-bg);
}

.select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M2 4l4 4 4-4' stroke='%236C757D' stroke-width='1.5' fill='none' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 16px center;
  padding-right: 40px;
}

.field__error {
  font-size: 0.8125rem;
  color: var(--color-error-text);
  display: none;
  align-items: center;
  gap: 6px;
}
.field__error i { font-size: 0.875rem; }
.field.has-error .field__error { display: flex; }
.field.has-error .input,
.field.has-error .select { border-color: var(--color-error-border); }

.field__hint {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
}

@media (max-width: 560px) {
  .form-grid { grid-template-columns: 1fr; }
  .form-grid .span-2 { grid-column: span 1; }
}

/* --------------------------------------------------------------------------
   12. Calculator Page Specifics
   -------------------------------------------------------------------------- */
.breadcrumb {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  padding: 24px 0 0;
}
.breadcrumb ol { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.breadcrumb li::after { content: '/'; margin-left: 8px; color: var(--color-text-muted); }
.breadcrumb li:last-child::after { content: ''; }
.breadcrumb a { color: var(--color-text-secondary); }
.breadcrumb a:hover { color: var(--color-accent); }
.breadcrumb [aria-current="page"] { color: var(--color-text); font-weight: 500; }

.page-header { padding: 24px 0 32px; }
.page-header h1 {
  font-size: clamp(2rem, 4vw, 2.75rem);
  margin-bottom: var(--space-3);
  letter-spacing: -0.03em;
}
.page-header p { color: var(--color-text-secondary); max-width: 640px; }

.unit-indicator {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: var(--color-primary-100);
  color: var(--color-primary);
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-size: 0.8125rem;
  font-weight: 600;
  margin: var(--space-5) 0 var(--space-6);
}
.unit-indicator i { color: var(--color-primary); }
.unit-indicator a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 2px;
  font-weight: 600;
}
.unit-indicator a:hover { color: var(--color-accent); }

.calc-card-main {
  background: var(--color-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: 32px;
}
@media (max-width: 560px) { .calc-card-main { padding: 20px; } }

.calc-actions {
  display: flex;
  gap: var(--space-4);
  margin-top: var(--space-6);
  flex-wrap: wrap;
}
.calc-actions .btn--accent { flex: 1; min-width: 200px; }

/* Results panel — grid-template-rows animation */
.results {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--dur-slow) var(--ease-out);
  margin-top: 0;
}
.results.is-open { grid-template-rows: 1fr; margin-top: var(--space-6); }
.results__inner { overflow: hidden; }

.results-summary {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}
@media (max-width: 560px) { .results-summary { grid-template-columns: 1fr; } }

.result-stat {
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  padding: 20px;
}
.result-stat__label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-secondary);
  margin-bottom: 6px;
}
.result-stat__value {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: -0.02em;
  line-height: 1.1;
}
.result-stat__value small {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  margin-left: 4px;
}
.result-stat__sub {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  margin-top: 4px;
}

.checklist {
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  margin-bottom: var(--space-5);
}
.checklist__title {
  font-weight: 700;
  font-size: 0.9375rem;
  margin-bottom: var(--space-3);
  display: flex;
  align-items: center;
  gap: 8px;
}
.checklist__title i { color: var(--color-accent); }
.checklist ul { display: flex; flex-direction: column; gap: 8px; }
.checklist li {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px 0;
  font-size: 0.9375rem;
  border-bottom: 1px dashed var(--color-border-soft);
}
.checklist li:last-child { border-bottom: none; }
.checklist input[type="checkbox"] {
  appearance: none;
  width: 20px; height: 20px;
  border: 2px solid var(--color-input-border);
  border-radius: 6px;
  cursor: pointer;
  position: relative;
  flex-shrink: 0;
  transition: background var(--dur-fast) var(--ease-standard),
              border-color var(--dur-fast) var(--ease-standard);
}
.checklist input[type="checkbox"]:checked {
  background: var(--color-primary);
  border-color: var(--color-primary);
}
.checklist input[type="checkbox"]:checked::after {
  content: '\f00c';
  font-family: 'Font Awesome 6 Free';
  font-weight: 900;
  color: #fff;
  font-size: 0.7rem;
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
}
.checklist li.is-checked label { text-decoration: line-through; color: var(--color-text-secondary); }
.checklist li label { cursor: pointer; flex: 1; }

.protip {
  background: var(--color-success-bg);
  border: 1px solid var(--color-success-border);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  display: flex;
  gap: 12px;
  margin-bottom: var(--space-5);
}
.protip__icon {
  color: var(--color-success-text);
  font-size: 1.125rem;
  flex-shrink: 0;
  margin-top: 2px;
}
.protip__body { font-size: 0.9375rem; color: var(--color-success-text); }
.protip__body strong { display: block; margin-bottom: 2px; }

.disclaimer {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  display: flex;
  gap: 8px;
  align-items: flex-start;
  padding: 12px 0 0;
  border-top: 1px solid var(--color-border-soft);
}
.disclaimer i { color: var(--color-text-muted); margin-top: 2px; }

.unit-note {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  margin-top: var(--space-4);
  display: flex;
  align-items: center;
  gap: 6px;
}

/* --------------------------------------------------------------------------
   13. FAQ Accordion
   -------------------------------------------------------------------------- */
.faq-list { display: flex; flex-direction: column; gap: 12px; }
.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--dur) var(--ease-standard);
}
.faq-item.is-open { border-color: var(--color-primary-100); }
.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 24px;
  text-align: left;
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-text);
  background: transparent;
}
.faq-question:hover { background: var(--color-surface-alt); }
.faq-question i {
  color: var(--color-accent);
  transition: transform var(--dur) var(--ease-out);
  font-size: 0.875rem;
}
.faq-item.is-open .faq-question i { transform: rotate(45deg); }
.faq-answer {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--dur) var(--ease-out);
}
.faq-item.is-open .faq-answer { grid-template-rows: 1fr; }
.faq-answer__inner {
  overflow: hidden;
  padding: 0 24px;
}
.faq-item.is-open .faq-answer__inner { padding: 0 24px 20px; }
.faq-answer p { color: var(--color-text-secondary); font-size: 0.9375rem; line-height: 1.65; }

/* --------------------------------------------------------------------------
   14. Related Tools
   -------------------------------------------------------------------------- */
.related-scroll {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
}
@media (max-width: 880px) {
  .related-scroll {
    grid-template-columns: 280px;
    grid-auto-flow: column;
    grid-auto-columns: 280px;
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    padding-bottom: 8px;
    margin: 0 -24px;
    padding-left: 24px;
    padding-right: 24px;
  }
  .related-scroll > * { scroll-snap-align: start; }
}
.related-card {
  display: block;
  text-decoration: none;
  color: inherit;
  background: var(--color-surface);
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  padding: 20px;
  transition: transform var(--dur) var(--ease-out),
              box-shadow var(--dur) var(--ease-out);
}
.related-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
  color: inherit;
}
.related-card__icon {
  width: 40px; height: 40px;
  border-radius: var(--radius-sm);
  background: var(--color-primary-100);
  color: var(--color-primary);
  display: grid;
  place-items: center;
  font-size: 1rem;
  margin-bottom: var(--space-3);
}
.related-card__title { font-weight: 700; font-size: 0.9375rem; margin-bottom: 4px; }
.related-card__desc { font-size: 0.8125rem; color: var(--color-text-secondary); }

/* --------------------------------------------------------------------------
   15. Footer
   -------------------------------------------------------------------------- */
.site-footer {
  background: var(--color-primary);
  color: rgba(255,255,255,0.85);
  padding: 64px 0 24px;
  margin-top: 80px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: var(--space-8);
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,0.12);
}
.footer-brand .brand { color: #fff; margin-bottom: var(--space-4); }
.footer-brand .brand-name b { color: #fff; }
.footer-brand p {
  color: rgba(255,255,255,0.7);
  font-size: 0.9375rem;
  max-width: 320px;
}
.footer-col h4 {
  color: #fff;
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: var(--space-4);
}
.footer-col ul { display: flex; flex-direction: column; gap: 10px; }
.footer-col a {
  color: rgba(255,255,255,0.75);
  font-size: 0.9375rem;
}
.footer-col a:hover { color: #fff; }
.footer-bottom {
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.8125rem;
  color: rgba(255,255,255,0.6);
}

@media (max-width: 720px) {
  .footer-grid { grid-template-columns: 1fr 1fr; gap: var(--space-6); }
  .footer-brand { grid-column: span 2; }
}

/* --------------------------------------------------------------------------
   16. Content / Prose Pages (about, privacy, contact)
   -------------------------------------------------------------------------- */
.prose { max-width: 720px; margin: 0 auto; }
.prose h2 { margin: var(--space-10) 0 var(--space-4); }
.prose h2:first-child { margin-top: 0; }
.prose h3 { margin: var(--space-6) 0 var(--space-3); }
.prose p { color: var(--color-text-secondary); margin-bottom: var(--space-4); }
.prose ul { list-style: disc; padding-left: 1.4em; margin-bottom: var(--space-4); }
.prose ul li { margin-bottom: 8px; color: var(--color-text-secondary); }
.prose strong { color: var(--color-text); }

.contact-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--space-10);
  align-items: start;
}
@media (max-width: 880px) { .contact-grid { grid-template-columns: 1fr; } }

.contact-channels { display: flex; flex-direction: column; gap: var(--space-4); margin-top: var(--space-6); }
.contact-channel {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 16px;
  border: 1px solid var(--color-border-soft);
  border-radius: var(--radius-md);
  background: var(--color-surface);
}
.contact-channel__icon {
  width: 40px; height: 40px;
  border-radius: var(--radius-sm);
  background: var(--color-primary-100);
  color: var(--color-primary);
  display: grid;
  place-items: center;
  flex-shrink: 0;
}
.contact-channel h4 { font-size: 0.9375rem; margin-bottom: 2px; }
.contact-channel p { font-size: 0.875rem; color: var(--color-text-secondary); margin: 0; }

/* --------------------------------------------------------------------------
   17. Utilities & Motion
   -------------------------------------------------------------------------- */
/* .fade-in base styles defined in section 2 (Reset & Base) so the no-js
   fallback rule lives next to the initial hidden state. */
.fade-in {
  transition: opacity var(--dur-slow) var(--ease-out),
              transform var(--dur-slow) var(--ease-out);
}

@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;
  }
  /* Make sure content is visible even if IntersectionObserver never fires */
  .fade-in { opacity: 1 !important; transform: none !important; }
}

/* Mobile section padding (spec: 48px on mobile) */
@media (max-width: 720px) {
  .section { padding: 48px 0; min-height: auto; }
  .section--tight { padding: 36px 0; }
  .section--alt { padding: 48px 0; }
}

.divider {
  height: 1px;
  background: var(--color-border-soft);
  margin: var(--space-8) 0;
  border: none;
}

/* Print friendliness */
@media print {
  .site-header, .site-footer, .nav-toggle, .unit-toggle, .related-scroll, .calc-actions { display: none !important; }
  body { background: #fff; }
}