/* ================================================================
   GravelCalculate.com — Unified Design System v2.0
   Single source of truth for all pages.
   ================================================================ */

/* ----- Design Tokens ----- */
:root {
  /* Brand Colors */
  --ds-primary: #16A34A;
  --ds-primary-hover: #15803D;
  --ds-primary-light: #DCFCE7;
  --ds-primary-bg: #F0FDF4;

  /* Neutrals */
  --ds-secondary: #475569;
  --ds-bg: #F8FAFC;
  --ds-card: #FFFFFF;
  --ds-border: #E2E8F0;
  --ds-border-light: #F1F5F9;
  --ds-text: #0F172A;
  --ds-text-secondary: #64748B;
  --ds-text-muted: #94A3B8;

  /* Accent */
  --ds-accent: #F59E0B;
  --ds-accent-light: #FEF3C7;

  /* Semantic */
  --ds-success: #16A34A;
  --ds-warning: #F59E0B;
  --ds-error: #EF4444;
  --ds-info: #3B82F6;

  /* Typography */
  --ds-font: 'Inter', ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  --ds-font-display: 'Inter', ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;

  /* Font Sizes */
  --ds-text-xs: 0.75rem;    /* 12px */
  --ds-text-sm: 0.875rem;   /* 14px */
  --ds-text-base: 1rem;     /* 16px */
  --ds-text-lg: 1.125rem;   /* 18px */
  --ds-text-xl: 1.25rem;    /* 20px */
  --ds-text-2xl: 1.5rem;    /* 24px */
  --ds-text-3xl: 2rem;      /* 32px */
  --ds-text-4xl: 2.25rem;   /* 36px */
  --ds-text-5xl: 3rem;      /* 48px */

  /* Spacing */
  --ds-space-xs: 0.25rem;   /* 4px */
  --ds-space-sm: 0.5rem;    /* 8px */
  --ds-space-md: 1rem;      /* 16px */
  --ds-space-lg: 1.5rem;    /* 24px */
  --ds-space-xl: 2rem;      /* 32px */
  --ds-space-2xl: 3rem;     /* 48px */
  --ds-space-3xl: 5rem;     /* 80px */

  /* Section Spacing */
  --ds-section-desktop: 80px;
  --ds-section-mobile: 48px;

  /* Border Radius */
  --ds-radius-sm: 8px;
  --ds-radius-md: 12px;
  --ds-radius-lg: 16px;
  --ds-radius-xl: 24px;
  --ds-radius-full: 9999px;

  /* Shadows */
  --ds-shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.05);
  --ds-shadow-md: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
  --ds-shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
  --ds-shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.04);

  /* Transitions */
  --ds-transition: 0.15s ease;

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

  /* Calculator specific */
  --ds-calc-input-height: 48px;
  --ds-calc-input-height-mobile: 44px;
  --ds-calc-radius: 12px;
}

/* ================================================================
   Reset & Base
   ================================================================ */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--ds-bg);
  color: var(--ds-text);
  font-family: var(--ds-font);
  font-size: var(--ds-text-base);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ================================================================
   Typography
   ================================================================ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--ds-font-display);
  font-weight: 700;
  line-height: 1.15;
  color: var(--ds-text);
  margin: 0;
}

h1 { font-size: var(--ds-text-5xl); letter-spacing: -0.025em; }
h2 { font-size: var(--ds-text-3xl); letter-spacing: -0.015em; }
h3 { font-size: var(--ds-text-2xl); letter-spacing: -0.01em; }
h4 { font-size: var(--ds-text-xl); }

p { margin: 0 0 var(--ds-space-md); color: var(--ds-text-secondary); line-height: 1.7; }

a { color: var(--ds-primary); text-decoration: none; transition: color var(--ds-transition); }
a:hover { color: var(--ds-primary-hover); }

/* ================================================================
   Top Bar / Header
   ================================================================ */
.ds-topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  height: 64px;
  padding: 0 var(--ds-space-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--ds-border);
}

.ds-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ds-text);
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -0.5px;
}

.ds-brand-icon {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: var(--ds-primary);
  color: #fff;
  font-size: 14px;
}

.ds-nav {
  display: flex;
  align-items: center;
  gap: var(--ds-space-sm);
  height: 100%;
}

.ds-nav a {
  display: flex;
  align-items: center;
  height: 100%;
  padding: 0 var(--ds-space-md);
  color: var(--ds-text-secondary);
  font-size: var(--ds-text-sm);
  font-weight: 600;
  border-bottom: 2px solid transparent;
  transition: all var(--ds-transition);
}

.ds-nav a:hover,
.ds-nav a.active {
  color: var(--ds-primary);
  border-bottom-color: var(--ds-primary);
}

.ds-header-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  background: var(--ds-primary);
  color: #fff !important;
  border-radius: var(--ds-radius-md);
  font-size: var(--ds-text-sm);
  font-weight: 700;
  text-decoration: none;
  transition: background var(--ds-transition);
}

.ds-header-cta:hover {
  background: var(--ds-primary-hover);
}

/* Mobile hamburger */
.ds-hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  color: var(--ds-text);
}

@media (max-width: 768px) {
  .ds-hamburger { display: block; }
  .ds-nav { display: none; }
  .ds-nav.open { display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0; background: #fff; border-bottom: 1px solid var(--ds-border); padding: var(--ds-space-md); box-shadow: var(--ds-shadow-lg); }
  .ds-nav.open a { height: auto; padding: 12px var(--ds-space-md); border-bottom: 0; border-radius: var(--ds-radius-sm); }
  .ds-nav.open a:hover { background: var(--ds-primary-bg); }
}

/* ================================================================
   Hero Section
   ================================================================ */
.ds-hero {
  padding: var(--ds-section-desktop) var(--ds-space-lg) var(--ds-space-2xl);
  max-width: var(--ds-container);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--ds-space-2xl);
  align-items: center;
}

.ds-hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: var(--ds-primary-light);
  color: var(--ds-primary);
  border-radius: var(--ds-radius-full);
  font-size: var(--ds-text-xs);
  font-weight: 700;
  letter-spacing: 0.5px;
  margin-bottom: var(--ds-space-lg);
}

.ds-hero h1 {
  font-size: var(--ds-text-5xl);
  line-height: 1.08;
  margin-bottom: var(--ds-space-md);
}

.ds-hero-subtitle {
  font-size: var(--ds-text-lg);
  color: var(--ds-text-secondary);
  line-height: 1.6;
  max-width: 540px;
  margin-bottom: var(--ds-space-xl);
}

.ds-hero-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 16px 32px;
  background: var(--ds-primary);
  color: #fff !important;
  border-radius: var(--ds-radius-md);
  font-size: var(--ds-text-base);
  font-weight: 700;
  text-decoration: none;
  transition: all var(--ds-transition);
  box-shadow: 0 4px 14px rgba(22,163,74,0.3);
}

.ds-hero-cta:hover {
  background: var(--ds-primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(22,163,74,0.35);
}

.ds-hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 320px;
}

.ds-hero-visual svg {
  width: 100%;
  max-width: 420px;
  height: auto;
}

@media (max-width: 768px) {
  .ds-hero {
    grid-template-columns: 1fr;
    padding: var(--ds-section-mobile) var(--ds-space-lg) var(--ds-space-xl);
    text-align: center;
  }
  .ds-hero-subtitle { margin-left: auto; margin-right: auto; }
  .ds-hero-visual { min-height: 200px; order: -1; }
  .ds-hero-visual svg { max-width: 280px; }
  .ds-hero h1 { font-size: var(--ds-text-4xl); }
}

/* ================================================================
   Calculator Card Container
   ================================================================ */
.ds-calculator-wrap {
  max-width: var(--ds-container);
  margin: 0 auto var(--ds-space-2xl);
  padding: 0 var(--ds-space-lg);
}

.ds-calculator-card {
  background: var(--ds-card);
  border: 1px solid var(--ds-border);
  border-radius: var(--ds-radius-xl);
  box-shadow: var(--ds-shadow-lg);
  overflow: hidden;
}

.ds-calculator-header {
  display: flex;
  align-items: center;
  gap: var(--ds-space-md);
  padding: var(--ds-space-xl) var(--ds-space-xl) var(--ds-space-lg);
  border-bottom: 1px solid var(--ds-border-light);
}

.ds-calculator-header-icon {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: var(--ds-radius-md);
  background: var(--ds-primary-bg);
  color: var(--ds-primary);
  font-size: 20px;
  flex-shrink: 0;
}

.ds-calculator-header h2 {
  font-size: var(--ds-text-2xl);
  margin: 0;
}

.ds-calculator-body {
  padding: var(--ds-space-xl);
}

/* Two-column calculator layout */
.ds-calc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--ds-space-xl);
}

@media (max-width: 900px) {
  .ds-calc-grid { grid-template-columns: 1fr; }
}

/* ================================================================
   Input Fields
   ================================================================ */
.ds-field {
  margin-bottom: var(--ds-space-lg);
}

.ds-field-label {
  display: block;
  margin-bottom: var(--ds-space-xs);
  font-size: var(--ds-text-sm);
  font-weight: 600;
  color: var(--ds-text);
}

.ds-field-sublabel {
  font-size: var(--ds-text-xs);
  color: var(--ds-text-muted);
  font-weight: 400;
  margin-left: var(--ds-space-xs);
}

.ds-input-group {
  display: flex;
  border: 1.5px solid var(--ds-border);
  border-radius: var(--ds-radius-md);
  overflow: hidden;
  transition: border-color var(--ds-transition), box-shadow var(--ds-transition);
}

.ds-input-group:focus-within {
  border-color: var(--ds-primary);
  box-shadow: 0 0 0 3px rgba(22,163,74,0.1);
}

.ds-input-group input {
  flex: 1;
  min-width: 0;
  height: var(--ds-calc-input-height);
  padding: 0 var(--ds-space-md);
  border: none;
  outline: none;
  background: transparent;
  font-size: var(--ds-text-base);
  font-weight: 600;
  color: var(--ds-text);
  font-family: var(--ds-font);
}

.ds-input-group input::placeholder {
  color: var(--ds-text-muted);
  font-weight: 400;
}

.ds-input-suffix {
  display: flex;
  align-items: center;
  padding: 0 var(--ds-space-md);
  background: var(--ds-bg);
  font-size: var(--ds-text-sm);
  font-weight: 600;
  color: var(--ds-text-secondary);
  border-left: 1px solid var(--ds-border);
  white-space: nowrap;
}

/* Select Dropdown */
.ds-select {
  width: 100%;
  height: var(--ds-calc-input-height);
  padding: 0 var(--ds-space-md);
  border: 1.5px solid var(--ds-border);
  border-radius: var(--ds-radius-md);
  background: #fff;
  font-size: var(--ds-text-base);
  font-weight: 600;
  color: var(--ds-text);
  font-family: var(--ds-font);
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%2364748B' viewBox='0 0 16 16'%3E%3Cpath d='M4.646 5.646a.5.5 0 0 1 .708 0L8 8.293l2.646-2.647a.5.5 0 0 1 .708.708l-3 3a.5.5 0 0 1-.708 0l-3-3a.5.5 0 0 1 0-.708z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 40px;
  transition: border-color var(--ds-transition), box-shadow var(--ds-transition);
}

.ds-select:focus {
  outline: none;
  border-color: var(--ds-primary);
  box-shadow: 0 0 0 3px rgba(22,163,74,0.1);
}

/* Dimension grid (length x width x depth) */
.ds-dimension-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--ds-space-sm);
}

@media (max-width: 480px) {
  .ds-dimension-grid { grid-template-columns: 1fr; }
}

/* Unit Toggle */
.ds-unit-toggle {
  display: inline-flex;
  border: 1px solid var(--ds-border);
  border-radius: var(--ds-radius-md);
  overflow: hidden;
  background: var(--ds-bg);
}

.ds-unit-toggle button {
  padding: 8px 16px;
  border: none;
  background: transparent;
  font-size: var(--ds-text-sm);
  font-weight: 600;
  color: var(--ds-text-secondary);
  cursor: pointer;
  transition: all var(--ds-transition);
  font-family: var(--ds-font);
}

.ds-unit-toggle button.active {
  background: #fff;
  color: var(--ds-primary);
  box-shadow: var(--ds-shadow-sm);
}

/* Mode Selector */
.ds-mode-selector {
  display: flex;
  gap: var(--ds-space-sm);
  margin-bottom: var(--ds-space-xl);
}

.ds-mode-btn {
  flex: 1;
  padding: 12px 16px;
  border: 1.5px solid var(--ds-border);
  border-radius: var(--ds-radius-md);
  background: #fff;
  font-size: var(--ds-text-sm);
  font-weight: 600;
  color: var(--ds-text-secondary);
  cursor: pointer;
  transition: all var(--ds-transition);
  font-family: var(--ds-font);
  text-align: center;
}

.ds-mode-btn.active {
  border-color: var(--ds-primary);
  background: var(--ds-primary-bg);
  color: var(--ds-primary);
}

.ds-mode-btn:hover:not(.active) {
  border-color: var(--ds-primary);
  background: var(--ds-bg);
}

/* ================================================================
   Buttons
   ================================================================ */
.ds-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  border: none;
  border-radius: var(--ds-radius-md);
  font-size: var(--ds-text-base);
  font-weight: 700;
  font-family: var(--ds-font);
  cursor: pointer;
  transition: all var(--ds-transition);
  text-decoration: none;
}

.ds-btn-primary {
  background: var(--ds-primary);
  color: #fff;
  box-shadow: 0 4px 14px rgba(22,163,74,0.25);
}

.ds-btn-primary:hover {
  background: var(--ds-primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(22,163,74,0.3);
}

.ds-btn-secondary {
  background: #fff;
  color: var(--ds-text-secondary);
  border: 1.5px solid var(--ds-border);
}

.ds-btn-secondary:hover {
  border-color: var(--ds-primary);
  color: var(--ds-primary);
}

.ds-btn-sm {
  padding: 8px 16px;
  font-size: var(--ds-text-sm);
}

.ds-btn-lg {
  padding: 18px 36px;
  font-size: var(--ds-text-lg);
}

.ds-btn-full {
  width: 100%;
}

/* ================================================================
   Result Cards
   ================================================================ */
.ds-results {
  display: grid;
  gap: var(--ds-space-md);
}

.ds-result-card {
  padding: var(--ds-space-lg);
  background: var(--ds-card);
  border: 1px solid var(--ds-border);
  border-radius: var(--ds-radius-lg);
  transition: transform var(--ds-transition), box-shadow var(--ds-transition);
}

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

.ds-result-card-primary {
  background: linear-gradient(135deg, var(--ds-primary) 0%, var(--ds-primary-hover) 100%);
  border-color: var(--ds-primary);
  color: #fff;
}

.ds-result-card-primary .ds-result-label,
.ds-result-card-primary .ds-result-desc { color: rgba(255,255,255,0.85); }

.ds-result-label {
  font-size: var(--ds-text-xs);
  font-weight: 600;
  color: var(--ds-text-muted);
  letter-spacing: 0.5px;
  text-transform: uppercase;
  margin-bottom: var(--ds-space-sm);
}

.ds-result-value {
  font-size: var(--ds-text-4xl);
  font-weight: 800;
  line-height: 1.1;
  color: var(--ds-text);
}

.ds-result-card-primary .ds-result-value { color: #fff; }

.ds-result-unit {
  font-size: var(--ds-text-lg);
  font-weight: 600;
  color: var(--ds-text-secondary);
  margin-top: var(--ds-space-xs);
}

.ds-result-card-primary .ds-result-unit { color: rgba(255,255,255,0.8); }

.ds-result-desc {
  font-size: var(--ds-text-xs);
  color: var(--ds-text-muted);
  margin-top: var(--ds-space-sm);
}

/* Result grid */
.ds-result-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--ds-space-md);
}

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

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

@media (max-width: 600px) {
  .ds-result-grid,
  .ds-result-grid-3,
  .ds-result-grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 400px) {
  .ds-result-grid,
  .ds-result-grid-3,
  .ds-result-grid-4 {
    grid-template-columns: 1fr;
  }
}

/* ================================================================
   Content Sections
   ================================================================ */
.ds-section {
  padding: var(--ds-section-desktop) var(--ds-space-lg);
  max-width: var(--ds-container);
  margin: 0 auto;
}

.ds-section-header {
  text-align: center;
  margin-bottom: var(--ds-space-2xl);
}

.ds-section-header h2 {
  font-size: var(--ds-text-3xl);
  margin-bottom: var(--ds-space-sm);
}

.ds-section-header p {
  font-size: var(--ds-text-lg);
  color: var(--ds-text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* Info Cards */
.ds-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--ds-space-lg);
}

.ds-card {
  padding: var(--ds-space-xl);
  background: var(--ds-card);
  border: 1px solid var(--ds-border);
  border-radius: var(--ds-radius-lg);
  box-shadow: var(--ds-shadow-sm);
  transition: transform var(--ds-transition), box-shadow var(--ds-transition);
}

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

.ds-card-icon {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border-radius: var(--ds-radius-md);
  background: var(--ds-primary-bg);
  color: var(--ds-primary);
  font-size: 22px;
  margin-bottom: var(--ds-space-md);
}

.ds-card h3 {
  font-size: var(--ds-text-xl);
  margin-bottom: var(--ds-space-sm);
}

.ds-card p {
  font-size: var(--ds-text-sm);
  color: var(--ds-text-secondary);
  margin: 0;
}

/* Tables */
.ds-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--ds-border);
  border-radius: var(--ds-radius-lg);
  background: var(--ds-card);
}

.ds-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--ds-text-sm);
}

.ds-table th {
  padding: 12px 16px;
  text-align: left;
  font-size: var(--ds-text-xs);
  font-weight: 700;
  color: var(--ds-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  background: var(--ds-bg);
  border-bottom: 1px solid var(--ds-border);
}

.ds-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--ds-border-light);
  color: var(--ds-text-secondary);
}

.ds-table tr:last-child td { border-bottom: 0; }
.ds-table tr:hover td { background: var(--ds-primary-bg); }
.ds-table .highlight td { background: var(--ds-primary-bg); color: var(--ds-primary); font-weight: 700; }

/* Highlight Box */
.ds-highlight-box {
  padding: var(--ds-space-lg);
  background: var(--ds-primary-bg);
  border: 1px solid var(--ds-primary);
  border-radius: var(--ds-radius-lg);
}

.ds-highlight-box h3 {
  color: var(--ds-primary);
  margin-bottom: var(--ds-space-sm);
}

/* Formula Box */
.ds-formula-box {
  padding: var(--ds-space-lg);
  background: var(--ds-bg);
  border: 1px solid var(--ds-border);
  border-radius: var(--ds-radius-md);
  font-family: 'SF Mono', 'Fira Code', 'Fira Mono', monospace;
  font-size: var(--ds-text-sm);
  color: var(--ds-text);
}

.ds-formula-box .ds-formula {
  font-size: var(--ds-text-lg);
  font-weight: 700;
  color: var(--ds-primary);
  margin-bottom: var(--ds-space-sm);
}

/* Callout */
.ds-callout {
  display: flex;
  gap: var(--ds-space-md);
  padding: var(--ds-space-lg);
  border-radius: var(--ds-radius-lg);
  background: var(--ds-accent-light);
  border: 1px solid var(--ds-accent);
}

.ds-callout-icon {
  font-size: 24px;
  flex-shrink: 0;
}

.ds-callout p {
  margin: 0;
  font-size: var(--ds-text-sm);
  color: var(--ds-text-secondary);
}

.ds-callout strong {
  color: var(--ds-text);
}

/* ================================================================
   FAQ Accordion
   ================================================================ */
.ds-faq {
  display: flex;
  flex-direction: column;
  gap: var(--ds-space-sm);
}

.ds-faq-item {
  border: 1px solid var(--ds-border);
  border-radius: var(--ds-radius-md);
  background: var(--ds-card);
  overflow: hidden;
}

.ds-faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--ds-space-md);
  padding: var(--ds-space-lg);
  border: none;
  background: none;
  font-size: var(--ds-text-base);
  font-weight: 600;
  color: var(--ds-text);
  cursor: pointer;
  text-align: left;
  font-family: var(--ds-font);
  line-height: 1.4;
}

.ds-faq-question:hover {
  color: var(--ds-primary);
}

.ds-faq-icon {
  flex-shrink: 0;
  font-size: 20px;
  transition: transform var(--ds-transition);
  color: var(--ds-text-muted);
}

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

.ds-faq-answer {
  padding: 0 var(--ds-space-lg) var(--ds-space-lg);
  font-size: var(--ds-text-sm);
  color: var(--ds-text-secondary);
  line-height: 1.7;
  display: none;
}

.ds-faq-item.open .ds-faq-answer {
  display: block;
}

/* ================================================================
   Internal Links Pills
   ================================================================ */
.ds-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--ds-space-sm);
}

.ds-link-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  background: var(--ds-bg);
  border: 1px solid var(--ds-border);
  border-radius: var(--ds-radius-full);
  font-size: var(--ds-text-sm);
  font-weight: 600;
  color: var(--ds-text-secondary);
  text-decoration: none;
  transition: all var(--ds-transition);
}

.ds-link-pill:hover {
  border-color: var(--ds-primary);
  color: var(--ds-primary);
  background: var(--ds-primary-bg);
}

/* ================================================================
   Footer
   ================================================================ */
.ds-footer {
  padding: var(--ds-space-2xl) var(--ds-space-lg);
  background: var(--ds-text);
  color: #fff;
  text-align: center;
}

.ds-footer-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-weight: 800;
  font-size: 18px;
  margin-bottom: var(--ds-space-sm);
}

.ds-footer p {
  color: rgba(255,255,255,0.6);
  font-size: var(--ds-text-sm);
  margin-bottom: var(--ds-space-lg);
}

.ds-footer-links {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--ds-space-lg);
  margin-bottom: var(--ds-space-lg);
}

.ds-footer-links a {
  color: rgba(255,255,255,0.7);
  font-size: var(--ds-text-sm);
  font-weight: 500;
  text-decoration: none;
  transition: color var(--ds-transition);
}

.ds-footer-links a:hover {
  color: #fff;
}

.ds-footer-copy {
  font-size: var(--ds-text-xs);
  color: rgba(255,255,255,0.4);
}

/* ================================================================
   Utility Classes
   ================================================================ */
.ds-container { max-width: var(--ds-container); margin: 0 auto; padding: 0 var(--ds-space-lg); }
.ds-text-center { text-align: center; }
.ds-mb-sm { margin-bottom: var(--ds-space-sm); }
.ds-mb-md { margin-bottom: var(--ds-space-md); }
.ds-mb-lg { margin-bottom: var(--ds-space-lg); }
.ds-mb-xl { margin-bottom: var(--ds-space-xl); }
.ds-mt-lg { margin-top: var(--ds-space-lg); }
.ds-mt-xl { margin-top: var(--ds-space-xl); }
.ds-hidden { display: none; }

/* ================================================================
   Responsive
   ================================================================ */
@media (max-width: 768px) {
  :root {
    --ds-calc-input-height: var(--ds-calc-input-height-mobile);
  }

  .ds-section {
    padding: var(--ds-section-mobile) var(--ds-space-lg);
  }

  .ds-section-header h2 {
    font-size: var(--ds-text-2xl);
  }

  .ds-calculator-header {
    padding: var(--ds-space-lg);
  }

  .ds-calculator-body {
    padding: var(--ds-space-lg);
  }

  .ds-result-value {
    font-size: var(--ds-text-3xl);
  }

  .ds-card-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .ds-calculator-header {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* ================================================================
   Print Styles
   ================================================================ */
@media print {
  .ds-topbar,
  .ds-footer,
  .ds-header-cta,
  .ds-hamburger { display: none; }

  body {
    background: #fff;
    color: #000;
  }

  .ds-calculator-card {
    box-shadow: none;
    border: 1px solid #ccc;
  }
}