/* ============================================
   Asphalt Calculator — Design System
   Industrial-Professional with warmth
   "Trusted contractor's digital toolbox"
   ============================================ */

/* ─── Design Tokens ─── */
:root {
  /* Colors */
  --color-asphalt: #1a1a1a;
  --color-aggregate: #2d2d2d;
  --color-gravel: #4a4a4a;
  --color-concrete: #e8e6e1;
  --color-striping: #f59e0b;
  --color-striping-hover: #d97706;
  --color-striping-glow: rgba(245, 158, 11, 0.15);
  --color-fresh-asphalt: #3b3b3b;
  --color-success: #22c55e;
  --color-success-bg: rgba(34, 197, 94, 0.1);
  --color-error: #ef4444;
  --color-error-bg: rgba(239, 68, 68, 0.1);
  --color-white: #ffffff;
  --color-muted: #9ca3af;
  --color-muted-light: #6b7280;
  --color-border: rgba(255, 255, 255, 0.06);
  --color-border-light: rgba(255, 255, 255, 0.1);
  --color-overlay: rgba(0, 0, 0, 0.5);

  /* Typography */
  --font-heading: 'Barlow Condensed', sans-serif;
  --font-body: 'Source Serif 4', serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Font Sizes */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1.0625rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.75rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;
  --text-6xl: 4rem;

  /* Spacing */
  --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;

  /* Layout */
  --max-width: 1200px;
  --calc-width: 680px;
  --sidebar-width: 460px;
  --header-height: 72px;

  /* Borders */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 1px 3px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 8px 24px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px rgba(245, 158, 11, 0.15);
  --shadow-card-hover: 0 8px 30px rgba(0, 0, 0, 0.6);

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --duration-fast: 150ms;
  --duration-base: 250ms;
  --duration-slow: 400ms;
  --duration-count: 600ms;
}


/* ─── Base Styles ─── */
body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.75;
  color: var(--color-concrete);
  background-color: var(--color-asphalt);
}

/* ─── Typography ─── */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--color-white);
  line-height: 1.15;
}

h1 {
  font-size: var(--text-5xl);
  font-weight: 700;
  letter-spacing: -1px;
}

h2 {
  font-size: var(--text-4xl);
  font-weight: 600;
  letter-spacing: -0.5px;
}

h3 {
  font-size: var(--text-2xl);
  font-weight: 600;
}

h4 {
  font-size: var(--text-xl);
  font-weight: 600;
}

p {
  color: var(--color-concrete);
  margin-bottom: var(--space-4);
}

p:last-child {
  margin-bottom: 0;
}

strong {
  font-weight: 700;
  color: var(--color-white);
}

/* Mono for numbers and formulas */
.mono {
  font-family: var(--font-mono);
}

/* Label style */
.label {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-muted);
}

/* Eyebrow text */
.eyebrow {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--color-striping);
}

/* ─── Layout ─── */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.section {
  padding: var(--space-20) 0;
}

.section--dark {
  background-color: var(--color-aggregate);
}

.section--darker {
  background-color: var(--color-asphalt);
}

/* Grid system */
.grid {
  display: grid;
  gap: var(--space-6);
}

.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-fit, minmax(300px, 1fr));
}

/* Flex utilities */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* Text alignment */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

/* ─── Header ─── */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  z-index: 1000;
  transition: background-color var(--duration-base) var(--ease-out),
              box-shadow var(--duration-base) var(--ease-out);
}

.site-header.scrolled {
  background-color: rgba(26, 26, 26, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 var(--color-border);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-white);
  text-decoration: none;
}

.site-logo .logo-icon {
  width: 36px;
  height: 36px;
  background: var(--color-striping);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-lg);
  color: var(--color-asphalt);
  font-weight: 800;
}

.nav-main {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-muted);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-sm);
  transition: color var(--duration-fast), background-color var(--duration-fast);
  text-decoration: none;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-white);
  background-color: rgba(255, 255, 255, 0.05);
}

/* Nav dropdown */
.nav-dropdown {
  position: relative;
}

.nav-dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 260px;
  background: var(--color-aggregate);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-xl);
  padding: var(--space-2);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: all var(--duration-base) var(--ease-out);
  z-index: 100;
}

.nav-dropdown:hover .nav-dropdown-menu,
.nav-dropdown.open .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.nav-dropdown-item {
  display: block;
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-concrete);
  border-radius: var(--radius-sm);
  transition: all var(--duration-fast);
  text-decoration: none;
}

.nav-dropdown-item:hover {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.05);
}

.nav-dropdown-item .dropdown-label {
  display: block;
  font-size: var(--text-xs);
  color: var(--color-muted-light);
  margin-top: 2px;
}

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

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-concrete);
  transition: all var(--duration-base) var(--ease-out);
  border-radius: 2px;
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}
.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

.mobile-nav {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--color-asphalt);
  z-index: 999;
  padding: var(--space-6);
  overflow-y: auto;
}

.mobile-nav.open {
  display: block;
}

.mobile-nav-link {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-concrete);
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--color-border);
  text-decoration: none;
}

.mobile-nav-link:hover {
  color: var(--color-striping);
}

.mobile-nav-sub {
  padding-left: var(--space-6);
}

.mobile-nav-sub a {
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-muted);
  padding: var(--space-3) 0;
  display: block;
  text-decoration: none;
}

.mobile-nav-sub a:hover {
  color: var(--color-white);
}


/* ─── Hero ─── */
.hero {
  min-height: 560px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--header-height) + var(--space-16)) var(--space-6) var(--space-16);
  position: relative;
  overflow: hidden;
  background: var(--color-asphalt);
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: 
    repeating-linear-gradient(
      45deg,
      transparent,
      transparent 2px,
      rgba(255, 255, 255, 0.008) 2px,
      rgba(255, 255, 255, 0.008) 4px
    );
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.03'/%3E%3C/svg%3E");
  background-size: 256px 256px;
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 820px;
}

.hero h1 {
  font-size: var(--text-6xl);
  margin-bottom: var(--space-6);
}

.hero h1 span {
  display: block;
  color: var(--color-muted);
  font-size: var(--text-4xl);
  font-weight: 500;
  margin-top: var(--space-2);
}

.hero-sub {
  font-size: var(--text-lg);
  color: var(--color-muted);
  max-width: 600px;
  margin: 0 auto var(--space-8);
  line-height: 1.7;
}

.hero-badges {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-6);
  flex-wrap: wrap;
  margin-bottom: var(--space-10);
}

.hero-badge {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-muted);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.hero-badge .badge-icon {
  font-size: var(--text-base);
}

/* Scroll indicator */
.scroll-indicator {
  margin-top: var(--space-10);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-striping);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.05em;
  animation: bounce 2s ease-in-out infinite;
}

.scroll-indicator svg {
  width: 20px;
  height: 20px;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(8px); }
}


/* ─── Calculator Section ─── */
.calc-section {
  padding: var(--space-16) 0 var(--space-20);
  background: var(--color-aggregate);
}

.calc-wrapper {
  max-width: 900px;
  margin: 0 auto;
}

/* Tabs */
.calc-tabs {
  display: flex;
  gap: var(--space-1);
  margin-bottom: var(--space-8);
  border-bottom: 1px solid var(--color-border-light);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.calc-tabs::-webkit-scrollbar {
  display: none;
}

.calc-tab {
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-muted);
  padding: var(--space-3) var(--space-5);
  border: none;
  background: none;
  cursor: pointer;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: all var(--duration-fast);
  position: relative;
}

.calc-tab:hover {
  color: var(--color-concrete);
}

.calc-tab.active {
  color: var(--color-striping);
  border-bottom-color: var(--color-striping);
}

/* Mobile tab dropdown */
.calc-tab-select {
  display: none;
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--color-fresh-asphalt);
  border: 1px solid var(--color-gravel);
  border-radius: var(--radius-md);
  color: var(--color-white);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: 500;
  margin-bottom: var(--space-6);
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%239ca3af' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-4) center;
}

/* Tab panels */
.calc-panel {
  display: none;
}

.calc-panel.active {
  display: block;
  animation: fadeIn var(--duration-base) var(--ease-out);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Form elements */
.calc-form {
  display: grid;
  gap: var(--space-6);
}

.calc-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-4);
}

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

.form-label {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.form-label .label-hint {
  font-weight: 400;
  text-transform: none;
  letter-spacing: normal;
  color: var(--color-muted-light);
  font-size: var(--text-xs);
  margin-left: var(--space-2);
}

.input-wrapper {
  position: relative;
  display: flex;
}

.form-input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--color-asphalt);
  border: 1px solid var(--color-gravel);
  border-radius: var(--radius-md);
  color: var(--color-white);
  font-family: var(--font-mono);
  font-size: var(--text-base);
  transition: border-color var(--duration-fast), box-shadow var(--duration-fast);
  min-height: 48px;
}

.form-input:focus {
  outline: none;
  border-color: var(--color-striping);
  box-shadow: 0 0 0 3px var(--color-striping-glow);
}

.form-input::placeholder {
  color: var(--color-muted-light);
  font-family: var(--font-body);
}

.form-input.error {
  border-color: var(--color-error);
  box-shadow: 0 0 0 3px var(--color-error-bg);
}

/* Unit toggle */
.unit-toggle {
  display: flex;
  border: 1px solid var(--color-gravel);
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-left: var(--space-2);
  flex-shrink: 0;
}

.unit-btn {
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-muted);
  background: var(--color-asphalt);
  border: none;
  cursor: pointer;
  transition: all var(--duration-fast);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  min-width: 36px;
}

.unit-btn.active {
  background: var(--color-striping);
  color: var(--color-asphalt);
}

/* Select / Dropdown */
.form-select {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--color-asphalt);
  border: 1px solid var(--color-gravel);
  border-radius: var(--radius-md);
  color: var(--color-white);
  font-family: var(--font-body);
  font-size: var(--text-base);
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%239ca3af' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-4) center;
  min-height: 48px;
  transition: border-color var(--duration-fast), box-shadow var(--duration-fast);
}

.form-select:focus {
  outline: none;
  border-color: var(--color-striping);
  box-shadow: 0 0 0 3px var(--color-striping-glow);
}

/* Calculate button */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-heading);
  font-weight: 700;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--duration-fast);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--color-striping);
  color: var(--color-asphalt);
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-lg);
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.btn-primary:hover {
  background: var(--color-striping-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-glow);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: transparent;
  color: var(--color-striping);
  border: 1px solid var(--color-striping);
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-base);
}

.btn-secondary:hover {
  background: var(--color-striping-glow);
}

.btn-ghost {
  background: transparent;
  color: var(--color-muted);
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
}

.btn-ghost:hover {
  color: var(--color-white);
  background: rgba(255, 255, 255, 0.05);
}

.btn-full {
  width: 100%;
}


/* ─── Result Cards ─── */
.calc-results {
  display: none;
  margin-top: var(--space-8);
}

.calc-results.visible {
  display: block;
  animation: fadeIn var(--duration-base) var(--ease-out);
}

.result-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}

.result-card {
  background: var(--color-asphalt);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  padding: var(--space-6);
  text-align: center;
  transition: border-color var(--duration-fast), box-shadow var(--duration-fast);
}

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

.result-card .result-label {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-muted);
  margin-bottom: var(--space-3);
}

.result-card .result-value {
  font-family: var(--font-mono);
  font-size: var(--text-3xl);
  font-weight: 700;
  color: var(--color-striping);
  line-height: 1;
}

.result-card .result-unit {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-muted);
  margin-top: var(--space-2);
}

/* Waste factor badge */
.result-waste {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--color-success-bg);
  border: 1px solid rgba(34, 197, 94, 0.2);
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-success);
  margin-bottom: var(--space-4);
}


/* ─── Formula Display ─── */
.formula-toggle {
  width: 100%;
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4);
  background: transparent;
  border: 1px solid var(--color-striping);
  border-radius: var(--radius-md);
  color: var(--color-striping);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  cursor: pointer;
  transition: background-color var(--duration-fast);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.formula-toggle:hover {
  background: var(--color-striping-glow);
}

.formula-toggle .toggle-arrow {
  transition: transform var(--duration-base) var(--ease-out);
  font-size: var(--text-xs);
}

.formula-toggle.open .toggle-arrow {
  transform: rotate(180deg);
}

.formula-content {
  display: none;
  margin-top: var(--space-4);
  padding: var(--space-6);
  background: var(--color-asphalt);
  border: 1px solid rgba(245, 158, 11, 0.2);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 2;
  color: var(--color-concrete);
}

.formula-content.open {
  display: block;
  animation: fadeIn var(--duration-base) var(--ease-out);
}

.formula-content .formula-line {
  color: var(--color-striping);
  font-weight: 700;
  font-size: var(--text-base);
  margin-bottom: var(--space-3);
}

.formula-content .formula-values {
  color: var(--color-muted);
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-3);
  margin-top: var(--space-3);
}


/* ─── CTA Buttons Row ─── */
.cta-row {
  display: flex;
  gap: var(--space-4);
  margin-top: var(--space-6);
  flex-wrap: wrap;
}


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

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--color-border-light);
}

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

.card-link:hover .card-title {
  color: var(--color-striping);
}

.card-icon {
  width: 48px;
  height: 48px;
  background: var(--color-striping-glow);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-xl);
  margin-bottom: var(--space-5);
}

.card-title {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: var(--space-3);
  transition: color var(--duration-fast);
}

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

.card-arrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  margin-top: var(--space-4);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-striping);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}


/* ─── How-To Steps ─── */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-8);
  counter-reset: step-counter;
}

.step {
  position: relative;
  padding: var(--space-8);
  background: var(--color-fresh-asphalt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  counter-increment: step-counter;
}

.step::before {
  content: counter(step-counter);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--color-striping);
  color: var(--color-asphalt);
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 700;
  border-radius: var(--radius-full);
  margin-bottom: var(--space-5);
}

.step-title {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: var(--space-3);
}

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


/* ─── Formula Explained Section ─── */
.formula-section .formula-box {
  background: var(--color-asphalt);
  border: 2px solid var(--color-striping);
  border-radius: var(--radius-md);
  padding: var(--space-8);
  margin: var(--space-8) 0;
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  color: var(--color-striping);
  text-align: center;
  line-height: 1.8;
}

.formula-section .formula-where {
  margin: var(--space-6) 0;
}

.formula-section .formula-where li {
  padding: var(--space-2) 0;
  color: var(--color-concrete);
  font-size: var(--text-base);
  position: relative;
  padding-left: var(--space-6);
}

.formula-section .formula-where li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--color-striping);
  font-weight: 700;
}

.formula-section .worked-example {
  background: var(--color-fresh-asphalt);
  border-radius: var(--radius-md);
  padding: var(--space-8);
  margin-top: var(--space-8);
}

.formula-section .worked-example h3 {
  color: var(--color-striping);
  margin-bottom: var(--space-4);
}

.formula-section .worked-example .calc-step {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-muted);
  padding: var(--space-1) 0;
}

.formula-section .worked-example .calc-result {
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  color: var(--color-success);
  font-weight: 700;
  margin-top: var(--space-3);
}


/* ─── Reference Table ─── */
.ref-table-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: var(--space-8) 0;
}

.ref-table {
  width: 100%;
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.ref-table thead {
  background: var(--color-fresh-asphalt);
}

.ref-table th {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-muted);
  padding: var(--space-4) var(--space-6);
  text-align: left;
  border-bottom: 1px solid var(--color-border-light);
}

.ref-table td {
  padding: var(--space-4) var(--space-6);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-concrete);
  border-bottom: 1px solid var(--color-border);
}

.ref-table tr:last-child td {
  border-bottom: none;
}

.ref-table tr:hover td {
  background: rgba(245, 158, 11, 0.03);
}

.ref-table td:first-child {
  color: var(--color-white);
  font-weight: 600;
}

.ref-table td:nth-child(2) {
  color: var(--color-striping);
  font-weight: 700;
}

.ref-table .table-note {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  color: var(--color-muted-light);
  font-style: italic;
  padding: var(--space-4) var(--space-6);
  border-top: 1px solid var(--color-border);
}


/* ─── FAQ Accordion ─── */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  max-width: 800px;
  margin: var(--space-8) auto 0;
}

.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color var(--duration-fast);
}

.faq-item:hover {
  border-color: var(--color-border-light);
}

.faq-question {
  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-fresh-asphalt);
  border: none;
  cursor: pointer;
  text-align: left;
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-white);
  transition: background-color var(--duration-fast);
}

.faq-question:hover {
  background: var(--color-gravel);
}

.faq-question .faq-icon {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-striping);
  transition: transform var(--duration-base) var(--ease-out);
}

.faq-item.open .faq-question .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--duration-base) var(--ease-out);
}

.faq-answer-inner {
  padding: 0 var(--space-6) var(--space-6);
  font-size: var(--text-base);
  color: var(--color-muted);
  line-height: 1.8;
}


/* ─── Trust / Social Proof ─── */
.trust-section {
  text-align: center;
}

.trust-intro {
  max-width: 700px;
  margin: 0 auto var(--space-10);
  color: var(--color-muted);
  font-size: var(--text-base);
  line-height: 1.8;
}

.trust-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-8);
  flex-wrap: wrap;
  margin-bottom: var(--space-12);
}

.trust-stat {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-concrete);
}

.trust-stat .check {
  color: var(--color-success);
  font-weight: 700;
}

/* Testimonials */
.testimonials {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.testimonial {
  background: var(--color-fresh-asphalt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-8);
  text-align: left;
  position: relative;
}

.testimonial::before {
  content: '"';
  font-family: var(--font-heading);
  font-size: 4rem;
  color: var(--color-striping);
  opacity: 0.3;
  position: absolute;
  top: var(--space-4);
  left: var(--space-6);
  line-height: 1;
}

.testimonial-text {
  font-style: italic;
  color: var(--color-concrete);
  font-size: var(--text-base);
  line-height: 1.7;
  margin-bottom: var(--space-5);
  position: relative;
  z-index: 1;
}

.testimonial-author {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-striping);
}

.testimonial-role {
  font-size: var(--text-xs);
  color: var(--color-muted-light);
  margin-top: 2px;
}


/* ─── Blog Preview ─── */
.blog-card {
  background: var(--color-fresh-asphalt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: transform var(--duration-base) var(--ease-out),
              box-shadow var(--duration-base) var(--ease-out);
}

.blog-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-card-hover);
}

.blog-card-img {
  width: 100%;
  height: 200px;
  background: var(--color-aggregate);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-muted-light);
  font-size: var(--text-3xl);
}

.blog-card-body {
  padding: var(--space-6);
}

.blog-card-category {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-striping);
  margin-bottom: var(--space-3);
}

.blog-card-title {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-white);
  margin-bottom: var(--space-3);
  transition: color var(--duration-fast);
  line-height: 1.3;
}

.blog-card:hover .blog-card-title {
  color: var(--color-striping);
}

.blog-card-excerpt {
  font-size: var(--text-sm);
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: var(--space-4);
}

.blog-card-link {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-striping);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}


/* ─── Footer ─── */
.site-footer {
  background: var(--color-asphalt);
  border-top: 1px solid var(--color-border);
  padding: var(--space-16) 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr repeat(3, 1fr);
  gap: var(--space-10);
  margin-bottom: var(--space-12);
}

.footer-brand .footer-logo {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: var(--space-3);
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.footer-brand .footer-logo .logo-icon {
  width: 32px;
  height: 32px;
  background: var(--color-striping);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-sm);
  color: var(--color-asphalt);
  font-weight: 800;
}

.footer-brand .footer-tagline {
  font-size: var(--text-sm);
  color: var(--color-muted-light);
  max-width: 280px;
  line-height: 1.6;
}

.footer-col h4 {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-muted);
  margin-bottom: var(--space-5);
}

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

.footer-col a {
  font-size: var(--text-sm);
  color: var(--color-muted-light);
  transition: color var(--duration-fast);
  text-decoration: none;
}

.footer-col a:hover {
  color: var(--color-striping);
}

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding: var(--space-6) 0;
}

.footer-bottom-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
  font-size: var(--text-xs);
  color: var(--color-muted-light);
}


/* ─── Breadcrumbs ─── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-4) 0;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-muted-light);
}

.breadcrumb a {
  color: var(--color-muted);
  text-decoration: none;
  transition: color var(--duration-fast);
}

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

.breadcrumb .sep {
  color: var(--color-gravel);
  font-size: var(--text-xs);
}

.breadcrumb .current {
  color: var(--color-white);
}

/* ─── Section Headers ─── */
.section-header {
  text-align: center;
  margin-bottom: var(--space-12);
}

.section-header .eyebrow {
  margin-bottom: var(--space-3);
}

.section-header h2 {
  margin-bottom: var(--space-4);
}

.section-header p {
  max-width: 600px;
  margin: 0 auto;
  color: var(--color-muted);
}

/* ─── Bookmark CTA ─── */
.bookmark-cta {
  margin-top: var(--space-8);
  padding: var(--space-5) var(--space-6);
  background: var(--color-striping-glow);
  border: 1px solid rgba(245, 158, 11, 0.2);
  border-radius: var(--radius-md);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-striping);
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* ─── Scroll Animations ─── */
.fade-up {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--duration-slow) var(--ease-out),
              transform var(--duration-slow) var(--ease-out);
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger children */
.stagger > .fade-up:nth-child(1) { transition-delay: 0ms; }
.stagger > .fade-up:nth-child(2) { transition-delay: 100ms; }
.stagger > .fade-up:nth-child(3) { transition-delay: 200ms; }
.stagger > .fade-up:nth-child(4) { transition-delay: 300ms; }
.stagger > .fade-up:nth-child(5) { transition-delay: 400ms; }
.stagger > .fade-up:nth-child(6) { transition-delay: 500ms; }


/* ─── Tooltip ─── */
.tooltip-trigger {
  position: relative;
  cursor: help;
  border-bottom: 1px dashed var(--color-muted-light);
}

.tooltip-trigger .tooltip-text {
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  padding: var(--space-3) var(--space-4);
  background: var(--color-gravel);
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: var(--text-xs);
  color: var(--color-concrete);
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition: opacity var(--duration-fast);
  z-index: 50;
}

.tooltip-trigger:hover .tooltip-text {
  opacity: 1;
}

/* ─── Cost Range Display ─── */
.cost-range {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.cost-line {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border);
}

.cost-line:last-child {
  border-bottom: none;
  padding-top: var(--space-4);
  margin-top: var(--space-2);
  border-top: 2px solid var(--color-striping);
}

.cost-label {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-muted);
}

.cost-value {
  font-family: var(--font-mono);
  font-size: var(--text-lg);
  color: var(--color-striping);
  font-weight: 700;
}

.cost-line:last-child .cost-label {
  font-size: var(--text-base);
  color: var(--color-white);
}

.cost-line:last-child .cost-value {
  font-size: var(--text-xl);
}

/* ─── Price hint ─── */
.price-hint {
  font-family: var(--font-body);
  font-size: var(--text-xs);
  color: var(--color-muted-light);
  margin-top: var(--space-1);
}


/* ============================================
   RESPONSIVE BREAKPOINTS — Mobile-First
   ============================================ */

@media (max-width: 1024px) {
  :root {
    --text-6xl: 3rem;
    --text-5xl: 2.5rem;
    --text-4xl: 2rem;
  }
  
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .testimonials {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --text-6xl: 2.5rem;
    --text-5xl: 2rem;
    --text-4xl: 1.75rem;
    --text-3xl: 1.5rem;
  }
  
  .section {
    padding: var(--space-12) 0;
  }
  
  .container {
    padding: 0 var(--space-4);
  }

  /* Header mobile */
  .nav-main {
    display: none;
  }
  
  .nav-toggle {
    display: flex;
  }

  /* Hero */
  .hero {
    min-height: 480px;
    padding-top: calc(var(--header-height) + var(--space-10));
    padding-bottom: var(--space-12);
  }
  
  .hero-badges {
    gap: var(--space-4);
  }

  /* Calculator */
  .calc-tabs {
    display: none;
  }
  
  .calc-tab-select {
    display: block;
  }
  
  .result-cards {
    grid-template-columns: 1fr;
    gap: var(--space-3);
  }
  
  .calc-row {
    grid-template-columns: 1fr;
  }

  /* Steps */
  .steps {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }

  /* Grid */
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
  
  .grid-auto {
    grid-template-columns: 1fr;
  }

  /* Testimonials */
  .testimonials {
    grid-template-columns: 1fr;
  }

  /* Footer */
  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }
  
  .footer-bottom-inner {
    flex-direction: column;
    text-align: center;
  }
  
  /* Trust stats */
  .trust-stats {
    flex-direction: column;
    gap: var(--space-4);
    align-items: center;
  }
  
  /* CTA row */
  .cta-row {
    flex-direction: column;
  }
  
  .cta-row .btn {
    width: 100%;
  }
}

@media (max-width: 480px) {
  :root {
    --text-6xl: 2rem;
    --text-5xl: 1.75rem;
  }
  
  .hero {
    min-height: 420px;
  }
  
  .hero-badge {
    font-size: var(--text-xs);
  }
  
  .ref-table th,
  .ref-table td {
    padding: var(--space-3) var(--space-4);
    font-size: var(--text-xs);
  }
}