/* ============================================
   HOUSEHOLD CALCULATORS - REDESIGN v2
   Clean, compact, calculator-first design
   Inspired by calculator.net's functional approach
   ============================================ */

:root {
  /* Primary palette */
  --color-primary: #1e40af;
  --color-primary-light: #eff6ff;
  --color-primary-dark: #172554;
  
  /* Grays (neutral, trustworthy) */
  --color-gray-50: #fafafa;
  --color-gray-100: #f3f4f6;
  --color-gray-200: #e5e7eb;
  --color-gray-300: #d1d5db;
  --color-gray-400: #9ca3af;
  --color-gray-500: #6b7280;
  --color-gray-600: #4b5563;
  --color-gray-700: #374151;
  --color-gray-800: #1f2937;
  --color-gray-900: #111827;
  
  /* Semantic colors */
  --color-success: #10b981;
  --color-success-light: #f0fdf4;
  --color-error: #ef4444;
  --color-warning: #f59e0b;
  --color-info: #3b82f6;
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-family-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, "Courier New", monospace;
  
  /* Spacing scale */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  
  /* Border radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  
  /* Shadows */
  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

/* Global Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: 15px;
  line-height: 1.6;
  color: var(--color-gray-800);
  background: #fff;
}

/* Typography */
h1 {
  font-size: 2rem;
  line-height: 1.2;
  font-weight: 600;
  color: var(--color-gray-900);
  margin-bottom: var(--space-md);
}

h2 {
  font-size: 1.5rem;
  line-height: 1.3;
  font-weight: 600;
  color: var(--color-gray-900);
  margin-bottom: var(--space-lg);
  margin-top: var(--space-2xl);
}

h3 {
  font-size: 1.125rem;
  line-height: 1.4;
  font-weight: 600;
  color: var(--color-gray-900);
  margin-bottom: var(--space-md);
}

h4 {
  font-size: 1rem;
  line-height: 1.5;
  font-weight: 600;
  color: var(--color-gray-900);
  margin-bottom: var(--space-sm);
}

p {
  margin-bottom: var(--space-md);
  color: var(--color-gray-600);
}

small {
  font-size: 0.875rem;
  color: var(--color-gray-500);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 150ms ease;
}

a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* Layout */
.wrap {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* Header */
.site-header {
  background: var(--color-gray-900);
  color: white;
  padding: var(--space-md) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid var(--color-gray-800);
}

.site-header .wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: white;
  display: flex;
  align-items: center;
}

.brand span {
  color: var(--color-primary);
  margin-left: 0.25rem;
}

.site-header nav {
  display: flex;
  gap: var(--space-lg);
}

.site-header nav a {
  color: var(--color-gray-300);
  font-size: 0.95rem;
  transition: color 150ms ease;
}

.site-header nav a:hover {
  color: white;
  text-decoration: none;
}

/* Hero Section (Minimal) */
.hero {
  background: linear-gradient(135deg, #f0f9ff 0%, #f8fafc 100%);
  padding: var(--space-2xl) 0;
  border-bottom: 1px solid var(--color-gray-200);
}

.hero .wrap {
  text-align: left;
}

.hero .eyebrow {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

.hero h1 {
  margin-bottom: var(--space-sm);
  color: var(--color-gray-900);
}

.hero .lede {
  font-size: 1.125rem;
  color: var(--color-gray-600);
  max-width: 600px;
  margin: 0;
}

/* Calculator Section - Two Column Layout */
.calculator-section {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  margin: var(--space-3xl) 0;
  align-items: start;
}

.calculator-form-area {
  background: var(--color-gray-50);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
}

.calculator-form-area h2 {
  font-size: 1.25rem;
  margin-top: 0;
  margin-bottom: var(--space-lg);
}

/* Form Fields */
.form-group {
  margin-bottom: var(--space-lg);
}

.form-group label {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-weight: 500;
  color: var(--color-gray-700);
  margin-bottom: var(--space-sm);
  font-size: 0.95rem;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  font-size: 1rem;
  border: 1px solid var(--color-gray-300);
  border-radius: var(--radius-md);
  font-family: var(--font-family);
  transition: all 150ms ease;
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.form-group small {
  display: block;
  margin-top: var(--space-xs);
  color: var(--color-gray-500);
}

/* Form Section Headers */
.form-section-header {
  background: var(--color-gray-100);
  padding: var(--space-md) 0;
  margin: var(--space-xl) 0 var(--space-lg) 0;
  border-top: 1px solid var(--color-gray-200);
  border-bottom: 1px solid var(--color-gray-200);
  font-weight: 600;
  color: var(--color-gray-900);
  font-size: 0.95rem;
  cursor: pointer;
  user-select: none;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.form-section-header:hover {
  background: var(--color-gray-200);
}

.form-section-header::before {
  content: '▶';
  display: inline-block;
  transition: transform 150ms ease;
  font-size: 0.75rem;
}

.form-section-header.expanded::before {
  transform: rotate(90deg);
}

.form-section {
  overflow: hidden;
  max-height: 0;
  transition: max-height 200ms ease;
}

.form-section.expanded {
  max-height: 1000px;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: var(--space-md) var(--space-xl);
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 150ms ease;
  font-family: var(--font-family);
}

.btn-primary {
  background: var(--color-primary);
  color: white;
  width: 100%;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  box-shadow: var(--shadow-md);
}

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

/* Results Section */
.results-area {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

.results-summary {
  background: var(--color-success-light);
  border: 1px solid var(--color-success);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
}

.results-summary h3 {
  margin-top: 0;
  color: var(--color-gray-900);
}

.big-number {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-success);
  line-height: 1;
  margin: var(--space-lg) 0;
  font-family: var(--font-family-mono);
}

.results-breakdown {
  background: white;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
}

.results-breakdown h3 {
  margin-top: 0;
  font-size: 1.125rem;
}

.result-row {
  display: flex;
  justify-content: space-between;
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-gray-100);
  font-size: 0.95rem;
}

.result-row:last-child {
  border-bottom: none;
}

.result-label {
  color: var(--color-gray-600);
  font-weight: 500;
}

.result-value {
  color: var(--color-gray-900);
  font-weight: 600;
  font-family: var(--font-family-mono);
}

/* Info Boxes */
.info-box {
  background: var(--color-primary-light);
  border-left: 4px solid var(--color-primary);
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  margin: var(--space-xl) 0;
}

.info-box h4 {
  margin-top: 0;
  color: var(--color-primary-dark);
}

.info-box p {
  margin-bottom: 0;
  color: var(--color-gray-700);
}

/* Content Section */
.section {
  padding: var(--space-3xl) 0;
  border-bottom: 1px solid var(--color-gray-100);
}

.section:last-of-type {
  border-bottom: none;
}

.section h2 {
  margin-top: 0;
}

/* Accordion / Collapsible */
.accordion {
  margin: var(--space-xl) 0;
}

.accordion-item {
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: var(--space-md);
}

.accordion-header {
  background: var(--color-gray-50);
  padding: var(--space-lg);
  cursor: pointer;
  font-weight: 600;
  color: var(--color-gray-900);
  border: none;
  width: 100%;
  text-align: left;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 150ms ease;
}

.accordion-header:hover {
  background: var(--color-gray-100);
}

.accordion-header::after {
  content: '+';
  font-size: 1.5rem;
  color: var(--color-primary);
}

.accordion-header.expanded::after {
  content: '−';
}

.accordion-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 200ms ease;
  background: white;
}

.accordion-content.expanded {
  max-height: 1000px;
  padding: var(--space-xl);
}

.accordion-content p {
  margin-bottom: var(--space-md);
}

.accordion-content p:last-child {
  margin-bottom: 0;
}

/* Footer */
footer {
  background: var(--color-gray-900);
  color: var(--color-gray-300);
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--color-gray-800);
  margin-top: var(--space-3xl);
}

footer .wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

footer a {
  color: var(--color-gray-300);
}

footer a:hover {
  color: white;
}

/* Responsive */
@media (max-width: 768px) {
  .calculator-section {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }
  
  h1 {
    font-size: 1.5rem;
  }
  
  h2 {
    font-size: 1.25rem;
  }
  
  .hero {
    padding: var(--space-xl) 0;
  }
  
  .hero h1 {
    margin-bottom: var(--space-xs);
  }
  
  .hero .lede {
    font-size: 1rem;
  }
  
  .big-number {
    font-size: 2rem;
  }
  
  footer .wrap {
    flex-direction: column;
    gap: var(--space-lg);
    text-align: center;
  }
}

@media (max-width: 480px) {
  .wrap {
    padding: 0 var(--space-md);
  }
  
  .calculator-form-area {
    padding: var(--space-lg);
  }
  
  .form-group input,
  .form-group select {
    font-size: 16px; /* Prevents zoom on iOS */
  }
  
  .results-area {
    gap: var(--space-lg);
  }
  
  .big-number {
    font-size: 1.75rem;
  }
}

/* Utilities */
.text-center {
  text-align: center;
}

.mb-1 { margin-bottom: var(--space-sm); }
.mb-2 { margin-bottom: var(--space-md); }
.mb-3 { margin-bottom: var(--space-lg); }
.mb-4 { margin-bottom: var(--space-xl); }

.mt-1 { margin-top: var(--space-sm); }
.mt-2 { margin-top: var(--space-md); }
.mt-3 { margin-top: var(--space-lg); }
.mt-4 { margin-top: var(--space-xl); }

.hidden {
  display: none;
}

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