/* ============================================================
   COMPONENTS.CSS — Reusable UI Components
   ============================================================ */

/* --- Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--white);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-md) 0;
  backdrop-filter: blur(8px);
  background: rgba(255,255,255,0.95);
}

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

.site-logo {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--color-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
}
.site-logo:hover {
  text-decoration: none;
  color: var(--color-primary-dark);
}
.site-logo span {
  color: var(--gray-900);
}

.nav-desktop {
  display: none;
  gap: var(--space-xl);
}
.nav-desktop a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--gray-600);
  text-decoration: none;
  padding: var(--space-xs) 0;
  position: relative;
}
.nav-desktop a:hover,
.nav-desktop a.active {
  color: var(--color-primary);
  text-decoration: none;
}
.nav-desktop a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width var(--transition-base);
}
.nav-desktop a:hover::after,
.nav-desktop a.active::after {
  width: 100%;
}

@media (min-width: 768px) {
  .nav-desktop {
    display: flex;
  }
  .mobile-nav-toggle {
    display: none !important;
  }
}

/* Mobile Nav Toggle */
.mobile-nav-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-xs);
}
.mobile-nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--gray-700);
  border-radius: 2px;
  transition: var(--transition-base);
}
.mobile-nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translateY(5px);
}
.mobile-nav-toggle.active span:nth-child(2) {
  opacity: 0;
}
.mobile-nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translateY(-5px);
}

/* Mobile Nav Menu */
.mobile-nav {
  display: none;
  position: fixed;
  top: 60px;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--white);
  z-index: 99;
  padding: var(--space-xl);
  flex-direction: column;
  gap: var(--space-md);
}
.mobile-nav.open {
  display: flex;
}
.mobile-nav a {
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--gray-700);
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border);
  text-decoration: none;
}
.mobile-nav a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

/* --- Breadcrumbs --- */
.breadcrumb {
  padding: var(--space-md) 0;
  max-width: var(--max-width);
  margin: 0 auto;
  padding-left: var(--space-md);
  padding-right: var(--space-md);
}
.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  font-size: 0.85rem;
  color: var(--gray-400);
}
.breadcrumb li {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}
.breadcrumb li::before {
  content: '›';
  color: var(--gray-300);
}
.breadcrumb li:first-child::before {
  content: '';
}
.breadcrumb a {
  color: var(--gray-500);
  text-decoration: none;
}
.breadcrumb a:hover {
  color: var(--color-primary);
}
.breadcrumb .current {
  color: var(--gray-700);
  font-weight: 500;
}

/* --- Summary Box --- */
.summary-box {
  background: linear-gradient(135deg, var(--color-surface-alt), var(--white));
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-md);
  padding: var(--space-lg) var(--space-xl);
  margin: var(--space-xl) 0;
  font-size: 1.05rem;
  line-height: 1.7;
}
.summary-box strong {
  display: block;
  font-family: var(--font-heading);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-primary);
  margin-bottom: var(--space-sm);
}

/* --- Author Byline --- */
.author-byline {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  font-size: 0.9rem;
  color: var(--gray-500);
  margin: var(--space-md) 0 var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--color-border);
}
.author-byline .author-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.85rem;
}
.author-byline .author-name {
  font-weight: 600;
  color: var(--gray-700);
}

/* --- Table of Contents --- */
.toc {
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  margin: var(--space-xl) 0;
}
.toc-title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: var(--space-md);
  color: var(--gray-800);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}
.toc-title::before {
  content: '📑';
}
.toc ol {
  counter-reset: toc-counter;
  padding-left: 0;
}
.toc li {
  counter-increment: toc-counter;
  margin-bottom: var(--space-xs);
}
.toc li::before {
  content: counter(toc-counter) '. ';
  color: var(--color-primary);
  font-weight: 600;
  font-size: 0.85rem;
}
.toc a {
  font-size: 0.92rem;
  color: var(--gray-600);
  text-decoration: none;
}
.toc a:hover {
  color: var(--color-primary);
  text-decoration: underline;
}
.toc .toc-sub {
  padding-left: var(--space-lg);
  margin-top: var(--space-xs);
}
.toc .toc-sub li::before {
  content: '– ';
  color: var(--gray-400);
}

/* --- FAQ Section --- */
.faq-section {
  margin: var(--space-3xl) 0;
}
.faq-section h2 {
  border-bottom: none;
}
.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-sm);
  overflow: hidden;
  transition: box-shadow var(--transition-base);
}
.faq-item:hover {
  box-shadow: var(--shadow-sm);
}
.faq-question {
  width: 100%;
  background: var(--color-surface-alt);
  border: none;
  padding: var(--space-md) var(--space-lg);
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--gray-800);
  font-family: var(--font-body);
  line-height: 1.5;
}
.faq-question:hover {
  background: var(--gray-100);
}
.faq-question::after {
  content: '+';
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--color-primary);
  transition: transform var(--transition-base);
  flex-shrink: 0;
  margin-left: var(--space-md);
}
.faq-item.open .faq-question::after {
  content: '−';
}
.faq-answer {
  display: none;
  padding: var(--space-md) var(--space-lg) var(--space-lg);
  line-height: 1.7;
  color: var(--gray-600);
}
.faq-item.open .faq-answer {
  display: block;
}

/* --- Comparison Table --- */
.comparison-table {
  overflow-x: auto;
  margin: var(--space-xl) 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}
.comparison-table table {
  min-width: 500px;
}
.comparison-table th {
  background: var(--color-primary);
  color: var(--white);
  padding: var(--space-md);
  font-weight: 600;
  text-align: left;
  font-size: 0.95rem;
}
.comparison-table td {
  padding: var(--space-sm) var(--space-md);
  border-bottom: 1px solid var(--color-border);
  font-size: 0.95rem;
}
.comparison-table tr:last-child td {
  border-bottom: none;
}
.comparison-table tr:hover {
  background: var(--gray-50);
}
.comparison-table .check {
  color: #22C55E;
  font-weight: 700;
}
.comparison-table .cross {
  color: #EF4444;
  font-weight: 700;
}

/* --- Card / Article Grid --- */
.card {
  background: var(--white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: box-shadow var(--transition-base), transform var(--transition-base);
}
.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.card-body {
  padding: var(--space-lg);
}
.card-label {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-primary);
  margin-bottom: var(--space-sm);
}
.card-title {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: var(--space-sm);
  line-height: 1.3;
}
.card-title a {
  color: inherit;
  text-decoration: none;
}
.card-title a:hover {
  color: var(--color-primary);
  text-decoration: none;
}
.card-excerpt {
  font-size: 0.9rem;
  color: var(--gray-500);
  line-height: 1.6;
}

/* --- Related Articles --- */
.related-articles {
  margin: var(--space-3xl) 0 var(--space-xl);
  padding-top: var(--space-2xl);
  border-top: 2px solid var(--color-border);
}
.related-articles h2 {
  border-bottom: none;
  margin-top: 0;
  font-size: 1.3rem;
}

/* --- Ad Slot --- */
.ad-slot {
  text-align: center;
  max-width: 728px;
  margin: var(--space-lg) auto;
}
.ad-slot:empty {
  display: none;
}

/* --- Calculator Widget --- */
.calculator-widget {
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  margin: var(--space-xl) 0;
}
.calculator-widget h3 {
  margin-top: 0;
  margin-bottom: var(--space-lg);
}

.calc-form {
  display: grid;
  gap: var(--space-lg);
}
.calc-field label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--gray-700);
  margin-bottom: var(--space-xs);
}
.calc-field input,
.calc-field select {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  background: var(--white);
  transition: border-color var(--transition-fast);
}
.calc-field input:focus,
.calc-field select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}
.calc-field .hint {
  font-size: 0.8rem;
  color: var(--gray-400);
  margin-top: var(--space-xs);
}

.calc-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-sm) var(--space-xl);
  background: var(--color-primary);
  color: var(--white);
  border: none;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: background var(--transition-fast), transform var(--transition-fast);
}
.calc-btn:hover {
  background: var(--color-primary-dark);
  transform: translateY(-1px);
}

.calc-result {
  display: none;
  margin-top: var(--space-lg);
  padding: var(--space-lg);
  background: var(--white);
  border: 2px solid var(--color-primary);
  border-radius: var(--radius-md);
}
.calc-result.visible {
  display: block;
}
.calc-result-value {
  font-family: var(--font-heading);
  font-size: 2rem;
  font-weight: 800;
  color: var(--color-primary);
}
.calc-result-label {
  font-size: 0.9rem;
  color: var(--gray-500);
  margin-top: var(--space-xs);
}

/* --- Category Nav --- */
.category-nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin: var(--space-lg) 0;
}
.category-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-md);
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--gray-600);
  text-decoration: none;
  transition: all var(--transition-fast);
}
.category-tag:hover,
.category-tag.active {
  background: var(--color-primary);
  color: var(--white);
  border-color: var(--color-primary);
  text-decoration: none;
}

/* --- CTA Box --- */
.cta-box {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: var(--white);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  text-align: center;
  margin: var(--space-2xl) 0;
}
.cta-box h3 {
  color: var(--white);
  margin-top: 0;
}
.cta-box p {
  color: rgba(255,255,255,0.9);
  max-width: 500px;
  margin: 0 auto var(--space-lg);
}
.cta-box .btn {
  display: inline-block;
  background: var(--white);
  color: var(--color-primary);
  padding: var(--space-sm) var(--space-xl);
  border-radius: var(--radius-sm);
  font-weight: 600;
  text-decoration: none;
  transition: transform var(--transition-fast);
}
.cta-box .btn:hover {
  transform: translateY(-2px);
  text-decoration: none;
}

/* --- Disclaimer Banner --- */
.disclaimer-banner {
  background: #FEF3C7;
  border: 1px solid #FDE68A;
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-lg) 0;
  font-size: 0.88rem;
  line-height: 1.6;
  color: #92400E;
}
.disclaimer-banner strong {
  display: block;
  margin-bottom: var(--space-xs);
}

/* --- Footer --- */
.site-footer {
  background: var(--gray-900);
  color: var(--gray-400);
  padding: var(--space-3xl) 0 var(--space-xl);
  margin-top: var(--space-3xl);
}
.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}
@media (min-width: 640px) {
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 768px) {
  .footer-grid { grid-template-columns: 2fr 1fr 1fr 1fr; }
}

.footer-brand p {
  font-size: 0.9rem;
  line-height: 1.6;
  max-width: 300px;
}
.footer-col h4 {
  color: var(--white);
  font-size: 0.9rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-md);
  margin-top: 0;
}
.footer-col ul {
  list-style: none;
  padding: 0;
}
.footer-col li {
  margin-bottom: var(--space-sm);
}
.footer-col a {
  color: var(--gray-400);
  font-size: 0.88rem;
  text-decoration: none;
}
.footer-col a:hover {
  color: var(--white);
  text-decoration: none;
}

.footer-bottom {
  border-top: 1px solid var(--gray-800);
  padding-top: var(--space-lg);
  font-size: 0.82rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-md);
}

/* --- Hero Section (Homepage) --- */
.hero {
  padding: var(--space-2xl) 0 var(--space-xl);
  text-align: center;
  background: linear-gradient(180deg, var(--color-surface-alt), var(--white));
}
.hero h1 {
  max-width: 700px;
  margin: 0 auto var(--space-lg);
}
.hero p {
  font-size: 1.15rem;
  color: var(--gray-500);
  max-width: 550px;
  margin: 0 auto;
  line-height: 1.7;
}

/* --- Page Header --- */
.page-header {
  padding: var(--space-2xl) 0 var(--space-lg);
  background: var(--color-surface-alt);
  border-bottom: 1px solid var(--color-border);
}
.page-header h1 {
  margin-bottom: var(--space-sm);
}
.page-header .subtitle {
  font-size: 1.1rem;
  color: var(--gray-500);
  max-width: 600px;
}