/* ===== Design Tokens ===== */
:root {
  /* Color palette */
  --color-primary: #0056b3;
  --color-primary-hover: #004494;
  --color-primary-light: #e8f0fe;
  --color-primary-dark: #003d80;
  --color-accent: #ff6b35;
  --color-bg: #f4f7fa;
  --color-surface: #ffffff;
  --color-text: #2d3748;
  --color-text-muted: #57667a;
  --color-border: #e2e8f0;
  --color-header: #00264d;
  --color-footer-bg: #1e293b;
  --color-footer-text: #b0bec5;
  --color-link: #0056b3;
  --color-menu-bg: #003366;
  --color-alert-bg: #fff3cd;
  --color-alert-text: #856404;
  --color-alert-border: #ffeeba;
  --color-example-bg: #e2f0cb;
  --color-example-text: #556b2f;
  --color-example-border: #d4edda;
  --color-search-result-bg: #f9f9f9;
  --color-shadow: rgba(0, 0, 0, 0.08);

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.12);

  /* Spacing scale */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 2.5rem;
  --space-3xl: 3rem;
  --space-4xl: 4rem;

  /* Typography */
  --font-family: 'DM Sans', 'Segoe UI', system-ui, sans-serif;
  --font-size-xs: 0.875rem;
  --font-size-sm: clamp(0.9375rem, 0.85rem + 0.3vw, 1.0625rem);
  --font-size-base: clamp(1.0625rem, 0.95rem + 0.35vw, 1.1875rem);
  --font-size-lg: clamp(1.1875rem, 1.05rem + 0.4vw, 1.3125rem);
  --font-size-h2: clamp(1.4375rem, 1.25rem + 0.6vw, 1.75rem);
  --font-size-h1: clamp(1.75rem, 1.4rem + 1.2vw, 2.375rem);
  --font-size-hero: clamp(2rem, 1.5rem + 1.5vw, 2.75rem);
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --line-height-tight: 1.2;
  --line-height-base: 1.6;
  --line-height-relaxed: 1.75;

  /* Layout */
  --container-max-width: 1200px;
  --border-radius-sm: 4px;
  --border-radius: 8px;
  --border-radius-lg: 12px;

  /* Focus */
  --focus-ring: 0 0 0 3px rgba(0, 86, 179, 0.4);

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.25s ease;
}

/* ===== Dark Theme ===== */
[data-theme="dark"] {
  --color-primary: #5b9bd5;
  --color-primary-hover: #7bb3e0;
  --color-primary-light: #1a2a3a;
  --color-primary-dark: #8ec5f0;
  --color-accent: #ff8c5a;
  --color-bg: #0f1419;
  --color-surface: #1a2028;
  --color-text: #d4dae0;
  --color-text-muted: #94a3b8;
  --color-border: #2a3540;
  --color-header: #0d1117;
  --color-footer-bg: #0d1117;
  --color-footer-text: #8899a6;
  --color-link: #5b9bd5;
  --color-menu-bg: #151d25;
  --color-alert-bg: #2a2200;
  --color-alert-text: #ffd666;
  --color-alert-border: #4d3d00;
  --color-example-bg: #1a2a1a;
  --color-example-text: #9ec89e;
  --color-example-border: #2a4a2a;
  --color-search-result-bg: #1a2028;
  --color-shadow: rgba(0, 0, 0, 0.3);

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
  --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.4);

  --focus-ring: 0 0 0 3px rgba(91, 155, 213, 0.4);
}

/* ===== Accessibility ===== */
.skip-link {
  position: absolute;
  top: -100%;
  inset-inline-start: var(--space-md);
  background: var(--color-primary);
  color: var(--color-surface);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--border-radius-sm);
  z-index: 1000;
  font-size: var(--font-size-base);
  text-decoration: none;
}

.skip-link:focus {
  inset-block-start: var(--space-sm);
}

.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;
}

:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
}

@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;
  }
}

/* ===== Global Styles ===== */
body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height-base);
  margin: 0;
  padding: 0;
  background: var(--color-bg);
  color: var(--color-text);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  transition: background-color 0.3s ease, color 0.3s ease;
}

:is(p, .es, .en, ul) {
  text-align: justify;
}

a {
  color: var(--color-link);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  text-decoration: underline;
}

ul {
  padding-inline-start: 20px;
}

ul li {
  margin: var(--space-xs) 0;
}

/* ===== Typography ===== */
h1 {
  font-size: var(--font-size-h1);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
}

h2 {
  font-size: var(--font-size-h2);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  border-block-end: 2px solid var(--color-border);
  padding-block-end: var(--space-xs);
  margin-top: var(--space-xl);
}

/* ===== Container ===== */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
  box-sizing: border-box;
}

main > .container {
  background: var(--color-surface);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-md);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-xl);
}

.container .es,
.container .en {
  display: none;
  margin: var(--space-lg) 0;
  text-align: start;
}

.container .active {
  display: block;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  padding: var(--space-sm) var(--space-lg);
  border: 2px solid transparent;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
  line-height: 1.5;
}

.btn:hover {
  text-decoration: none;
}

.btn--primary {
  background: var(--color-primary);
  color: #fff;
}

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

.btn--secondary {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn--secondary:hover {
  background: var(--color-primary-light);
}

.btn--lg {
  padding: 0.75rem var(--space-xl);
  font-size: var(--font-size-lg);
  border-radius: var(--border-radius);
}

/* Base button styles (zero specificity) */
:where(button, #menu-toggle) {
  background-color: var(--color-primary);
  color: white;
  border: none;
  padding: var(--space-sm) var(--space-lg);
  font-size: var(--font-size-base);
  font-family: var(--font-family);
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  transition: background-color var(--transition-base);
}

:where(button, #menu-toggle):hover {
  background-color: var(--color-primary-hover);
}

/* ===== TopNav ===== */
.topnav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--color-header);
  padding: 0 var(--space-lg);
  min-height: 56px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-md);
}

.topnav__brand {
  color: #fff;
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  text-decoration: none;
  white-space: nowrap;
  letter-spacing: -0.01em;
}

.topnav__brand:hover {
  text-decoration: none;
  opacity: 0.9;
}

.topnav__toggle {
  display: none;
  background: none;
  border: none;
  color: #fff;
  font-size: 1.5rem;
  cursor: pointer;
  padding: var(--space-sm);
  line-height: 1;
}

.topnav__menu {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.topnav__links {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--space-xs);
}

.topnav__links a {
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--border-radius-sm);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.topnav__links a:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.1);
  text-decoration: none;
}

.topnav__actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.theme-toggle {
  background: none;
  border: none;
  color: rgba(255, 255, 255, 0.7);
  font-size: 1.25rem;
  cursor: pointer;
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--border-radius-sm);
  transition: all var(--transition-fast);
  line-height: 1;
  display: flex;
  align-items: center;
}

.theme-toggle:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.1);
}

.theme-toggle__icon::before {
  content: '\263E';
}

[data-theme="dark"] .theme-toggle__icon::before {
  content: '\2600';
}

/* Language dropdown */
.topnav__lang-dropdown {
  position: relative;
  margin-inline-start: var(--space-sm);
}

.topnav__lang-btn {
  display: flex;
  align-items: center;
  gap: 4px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 20px;
  color: #fff;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  padding: 5px 14px;
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.topnav__lang-btn:hover,
.topnav__lang-btn[aria-expanded="true"] {
  background: rgba(255, 255, 255, 0.22);
  border-color: rgba(255, 255, 255, 0.4);
}

.topnav__lang-menu {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  list-style: none;
  padding: 6px;
  min-width: 130px;
  z-index: 200;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.18);
}

.topnav__lang-menu.open {
  display: block;
}

.topnav__lang-menu li {
  margin: 0;
}

.topnav__lang-menu a {
  display: block;
  padding: 8px 14px;
  color: var(--color-text);
  text-decoration: none;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  border-radius: var(--border-radius-sm);
  transition: background var(--transition-fast);
}

.topnav__lang-menu a:hover {
  background: var(--color-primary-light);
  color: var(--color-primary);
  text-decoration: none;
}

/* Active nav link indicator */
.topnav__links a[aria-current="page"] {
  color: #fff;
  background: rgba(255, 255, 255, 0.12);
}

/* Component injection fade-in */
.component-loading {
  min-height: 56px;
  background: var(--color-header);
}

.component-loaded {
  animation: fadeIn 0.2s ease both;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

/* Injection error fallback */
.component-error {
  text-align: center;
  padding: var(--space-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.component-error a {
  color: var(--color-link);
}

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--color-header) 0%, #003d80 100%);
  color: #fff;
  padding: var(--space-4xl) var(--space-lg);
  text-align: center;
}

.hero__inner {
  max-width: var(--container-max-width);
  margin: 0 auto;
}

.hero__title {
  font-size: var(--font-size-hero);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  margin: 0 0 var(--space-md);
  color: #fff;
  border: none;
  padding: 0;
}

.hero__subtitle {
  font-size: var(--font-size-lg);
  color: rgba(255, 255, 255, 0.85);
  max-width: 640px;
  margin: 0 auto var(--space-xl);
  text-align: center;
  line-height: var(--line-height-relaxed);
}

/* ===== Card Grid ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-lg);
  margin: var(--space-xl) 0;
}

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-lg);
  padding: var(--space-xl);
  text-decoration: none;
  color: var(--color-text);
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
  position: relative;
}

.card:hover {
  box-shadow: var(--shadow-hover);
  border-color: var(--color-primary);
  transform: translateY(-2px);
  text-decoration: none;
  color: var(--color-text);
}

.card__icon {
  font-size: 2rem;
  margin-bottom: var(--space-md);
  line-height: 1;
}

.card__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin: 0 0 var(--space-sm);
  color: var(--color-text);
}

.card__desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin: 0;
  line-height: var(--line-height-relaxed);
  text-align: start;
}

.card--disabled {
  opacity: 0.6;
  cursor: default;
  pointer-events: none;
}

.card--disabled:hover {
  box-shadow: none;
  border-color: var(--color-border);
  transform: none;
}

.badge {
  display: inline-block;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 2px 8px;
  border-radius: 9999px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  margin-inline-start: var(--space-sm);
  vertical-align: middle;
}

/* ===== Search Panel ===== */
.search-panel {
  background: var(--color-surface);
  border-radius: var(--border-radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--shadow-md);
  max-width: 640px;
  margin: var(--space-xl) auto;
}

.search-panel__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin: 0 0 var(--space-md);
  color: var(--color-text);
  border: none;
  padding: 0;
}

.search-box {
  display: flex;
  gap: var(--space-sm);
  align-items: stretch;
}

.search-box__input-wrap {
  flex: 1;
  position: relative;
}

.search-box__icon {
  position: absolute;
  inset-inline-start: var(--space-md);
  inset-block-start: 50%;
  transform: translateY(-50%);
  color: var(--color-text-muted);
  font-size: var(--font-size-lg);
  pointer-events: none;
}

.search-box__input {
  width: 100%;
  padding: 0.625rem var(--space-md) 0.625rem 2.5rem; /* asymmetric for search icon */
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  font-size: var(--font-size-base);
  font-family: var(--font-family);
  background: var(--color-bg);
  color: var(--color-text);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  box-sizing: border-box;
}

.search-box__input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: var(--focus-ring);
}

/* ===== Breadcrumbs ===== */
.breadcrumbs {
  max-width: var(--container-max-width);
  margin: var(--space-md) auto;
  padding: 0 var(--space-lg);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.breadcrumbs a {
  color: var(--color-text-muted);
  text-decoration: none;
}

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

.breadcrumbs__sep {
  margin: 0 var(--space-sm);
  color: var(--color-border);
}

/* ===== Site Footer ===== */
.site-footer {
  background: var(--color-footer-bg);
  color: var(--color-footer-text);
  margin-top: auto;
  padding: var(--space-3xl) var(--space-lg) var(--space-xl);
}

.site-footer__inner {
  max-width: var(--container-max-width);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xl);
  text-align: center;
}

.site-footer__links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-md) var(--space-xl);
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-footer__links a {
  color: var(--color-footer-text);
  font-size: var(--font-size-sm);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.site-footer__links a:hover {
  color: #fff;
  text-decoration: none;
}

.site-footer__support {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
}

.site-footer__support p {
  margin: 0;
  font-size: var(--font-size-sm);
  text-align: center;
}

.site-footer__support img {
  height: 56px;
  width: auto;
  transition: opacity var(--transition-fast);
}

.site-footer__support img:hover {
  opacity: 0.85;
}

.site-footer__contact {
  font-size: var(--font-size-sm);
}

.site-footer__contact a {
  color: rgba(255, 255, 255, 0.8);
}

.site-footer__contact a:hover {
  color: #fff;
}

.site-footer__disclaimer {
  font-size: var(--font-size-xs);
  color: rgba(148, 163, 184, 0.7);
  border-block-start: 1px solid rgba(255, 255, 255, 0.08);
  padding-block-start: var(--space-lg);
  width: 100%;
  text-align: center;
  margin: 0;
}

/* ===== Accordion ===== */
summary {
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

.accordion-title {
  font-size: var(--font-size-h2);
  font-weight: bold;
  color: var(--color-primary);
  padding-inline-start: var(--space-lg);
  position: relative;
  cursor: pointer;
  margin-block-end: var(--space-md);
}

.accordion-title::before {
  content: '\25B6';
  position: absolute;
  inset-inline-start: 0;
  inset-block-start: 0.1rem;
  font-size: 1.2rem;
  transition: transform var(--transition-fast);
}

details[open] .accordion-title::before {
  transform: rotate(90deg);
}

/* ===== FAQ Items ===== */
.faq-item {
  margin-block-end: 0;
  border-bottom: 1px solid var(--color-border, #e0e0e0);
}

.faq-item summary {
  font-weight: 600;
  cursor: pointer;
  padding: var(--space-sm) 0;
  padding-inline-start: var(--space-lg);
  position: relative;
  color: var(--color-text);
}

.faq-item summary::before {
  content: '\25B6';
  position: absolute;
  inset-inline-start: 0;
  font-size: 0.75rem;
  transition: transform var(--transition-fast);
  color: var(--color-primary);
  top: 50%;
  transform: translateY(-50%);
}

.faq-item[open] summary::before {
  transform: translateY(-50%) rotate(90deg);
}

.faq-item p {
  padding-inline-start: var(--space-lg);
  margin-block-start: 0;
}

/* ===== Search Bar & Results (legacy) ===== */
.search-bar {
  display: flex;
  justify-content: center;
  align-items: center;
  margin: var(--space-lg) auto;
  max-width: 600px;
}

.search-bar input[type="text"] {
  width: 100%;
  padding: var(--space-sm);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-sm);
  font-size: var(--font-size-base);
  font-family: var(--font-family);
  box-shadow: 0 2px 4px var(--color-shadow);
  background: var(--color-surface);
  color: var(--color-text);
}

.search-bar button {
  margin-inline-start: var(--space-sm);
}

.search-result {
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-md);
  margin: var(--space-sm) 0;
  background-color: var(--color-search-result-bg);
  box-shadow: 0 2px 4px var(--color-shadow);
}

.search-result h3 {
  margin: 0;
  font-size: calc(var(--font-size-base) + 0.125rem);
  color: var(--color-primary);
}

.search-result p {
  margin-top: var(--space-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

/* ===== Alert & Example Boxes ===== */
.alert {
  background: var(--color-alert-bg);
  color: var(--color-alert-text);
  border: 1px solid var(--color-alert-border);
  padding: 15px;
  border-radius: var(--border-radius);
  margin-top: var(--space-xl);
}

.example-box {
  background: var(--color-example-bg);
  color: var(--color-example-text);
  border: 1px solid var(--color-example-border);
  padding: 15px;
  border-radius: var(--border-radius-sm);
  margin-top: var(--space-md);
}

/* ===== Figure Inline ===== */
.figure-inline          { display: flex; align-items: center; gap: var(--space-xl); margin: var(--space-xl) 0; }
.figure-inline__media   { max-width: 30%; flex-shrink: 0; }
.figure-inline__media img { width: 100%; height: auto; }
.figure-inline__caption { flex: 1; text-align: justify; }

/* ===== Scroll-to-Top ===== */
.scroll-top {
  position: fixed;
  inset-block-end: var(--space-xl);
  inset-inline-end: var(--space-xl);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  border: none;
  font-size: 1.25rem;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  z-index: 90;
  transition: opacity var(--transition-base), transform var(--transition-base);
  display: flex;
  align-items: center;
  justify-content: center;
}

.scroll-top:hover {
  background: var(--color-primary-hover);
  transform: translateY(-2px);
}

.scroll-top[hidden] {
  display: none;
}

/* ===== Reading Progress ===== */
.reading-progress {
  position: fixed;
  inset-block-start: 0;
  inset-inline-start: 0;
  height: 3px;
  background: var(--color-accent);
  z-index: 101;
  width: 0;
  transition: none;
  animation: reading-progress-fill linear forwards;
}

@keyframes reading-progress-fill {
  from { width: 0; }
  to   { width: 100%; }
}

/* ===== Reading Time ===== */
.reading-time {
  display: inline-block;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  background: var(--color-bg);
  padding: 0.15em 0.6em;
  border-radius: 999px;
  margin-block-end: var(--space-md);
}

/* ===== Table of Contents ===== */
.toc {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-md);
  margin-block-end: var(--space-xl);
}

.toc__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  cursor: pointer;
  list-style: none;
  padding: 0;
}

.toc__title::-webkit-details-marker { display: none; }

.toc__list,
.toc__sublist {
  margin: var(--space-sm) 0 0;
  padding-inline-start: var(--space-lg);
  list-style: decimal;
}

.toc__sublist {
  list-style: lower-alpha;
  margin-block-start: var(--space-xs);
}

.toc__link {
  color: var(--color-text);
  text-decoration: none;
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
  transition: color var(--transition-fast);
}

.toc__link:hover {
  color: var(--color-primary);
  text-decoration: underline;
}

.toc__link.active {
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
}

/* Desktop: sidebar TOC */
@media (min-width: 1024px) {
  .container.has-toc {
    display: grid;
    grid-template-columns: 1fr 240px;
    column-gap: var(--space-xl);
    row-gap: 0;
  }

  .container.has-toc > h1 {
    grid-column: 1 / -1;
  }

  .container.has-toc > *:not(.toc) {
    grid-column: 1;
  }

  .toc {
    position: sticky;
    inset-block-start: 72px;
    align-self: start;
    max-height: calc(100vh - 100px);
    overflow-y: auto;
    grid-column: 2;
    grid-row: 2 / 20;
  }
}

/* ===== Scroll Animations ===== */
.animate-ready {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.animate-in {
  opacity: 1;
  transform: translateY(0);
}

/* ===== View Transitions ===== */
@view-transition { navigation: auto; }
.topnav { view-transition-name: navbar; }
.site-footer { view-transition-name: footer; }

/* ===== Search Highlighting ===== */
mark {
  background: var(--color-alert-bg);
  color: var(--color-alert-text);
  padding: 0 2px;
  border-radius: 2px;
}

/* ===== Live Search Dropdown ===== */
.search-dropdown {
  position: absolute;
  inset-block-start: 100%;
  inset-inline-start: 0;
  inset-inline-end: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-md);
  max-height: 320px;
  overflow-y: auto;
  z-index: 200;
  margin-block-start: var(--space-xs);
}

.search-dropdown[hidden] {
  display: none;
}

.search-dropdown__item {
  padding: var(--space-sm) var(--space-md);
  border-block-end: 1px solid var(--color-border);
  cursor: pointer;
  transition: background var(--transition-fast);
}

.search-dropdown__item:last-child {
  border-block-end: none;
}

.search-dropdown__item:hover,
.search-dropdown__item--active {
  background: var(--color-primary-light);
}

.search-dropdown__item a {
  color: var(--color-text);
  text-decoration: none;
  display: block;
}

/* ===== Media Queries ===== */
@media (max-width: 1024px) {
  /* TopNav mobile */
  .topnav {
    flex-wrap: wrap;
    padding: 0 var(--space-md);
    gap: 0;
  }

  .topnav__toggle {
    display: block;
  }

  .topnav__menu {
    display: none;
    flex-direction: column;
    width: 100%;
    padding-bottom: var(--space-sm);
    align-items: stretch;
  }

  .topnav__menu.show {
    display: flex;
  }

  .topnav__links {
    flex-direction: column;
    gap: 0;
  }

  .topnav__links a {
    padding: var(--space-sm) var(--space-md);
  }

  .topnav__actions {
    justify-content: center;
    padding: var(--space-sm) 0;
    border-block-start: 1px solid rgba(255, 255, 255, 0.1);
  }

  .topnav__lang-menu {
    right: auto;
    left: 50%;
    transform: translateX(-50%);
  }

  /* Disable card lift on touch devices */
  .card:hover {
    transform: none;
  }

  .card:active {
    transform: scale(0.98);
  }

  /* Hero mobile */
  .hero {
    padding: var(--space-3xl) var(--space-md);
  }

  /* Card grid: 2-column on tablet, 1-column on phone (below 481px) */
  .card-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Search box mobile */
  .search-box {
    flex-direction: column;
  }

  /* Figure inline mobile */
  .figure-inline        { flex-direction: column; }
  .figure-inline__media { max-width: 100%; }

  /* Search bar mobile */
  .search-bar {
    flex-direction: column;
    gap: var(--space-sm);
  }

  .search-bar button {
    width: 100%;
    margin-inline-start: 0;
  }
}

/* ===== Table Overflow (mobile) ===== */
@media (max-width: 768px) {
  .comparison-table,
  .quick-ref {
    display: block;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
}

/* ===== Tablet / Small Screen (≤600px) ===== */
@media (max-width: 600px) {
  :is(p, .es, .en, ul) {
    text-align: start;
  }

  .container {
    padding: var(--space-lg) var(--space-md);
  }

  .hero {
    padding: var(--space-xl) var(--space-md);
  }

  .card {
    padding: var(--space-lg);
  }
}

/* ===== Print Styles ===== */
@media print {
  :is(nav, .topnav, .site-footer,
  .hero, .search-panel, .search-box, .search-bar,
  .theme-toggle, .skip-link, .scroll-top, .reading-progress,
  .reading-time, .print-bar,
  .toc, #navbar-placeholder, #footer-placeholder) {
    display: none !important;
  }

  body {
    background: #fff;
    color: #000;
    font-size: 12pt;
  }

  main > .container {
    max-width: 100%;
    box-shadow: none;
    border-radius: 0;
    background: none;
    margin: 0;
    padding: 0.5cm;
  }

  a[href]::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: #555;
  }

  a[href^="#"]::after,
  a[href^="javascript"]::after {
    content: "";
  }
}

@media (max-width: 480px) {
  .container {
    padding: var(--space-md) var(--space-sm);
  }

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

  .card {
    padding: var(--space-md);
  }

  .hero {
    padding: var(--space-xl) var(--space-sm);
  }

  .breadcrumbs {
    padding: 0 var(--space-sm);
  }

  .alert,
  .example-box {
    padding: var(--space-sm);
  }

  .scroll-top {
    width: 38px;
    height: 38px;
    font-size: 1rem;
  }

  h1 {
    font-size: var(--font-size-h1);
  }

  p, .search-bar input[type="text"], .search-bar button {
    font-size: var(--font-size-sm);
    padding: var(--space-sm);
  }
}

/* ===== Last Updated ===== */
.last-updated {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-block-start: calc(-1 * var(--space-sm));
  margin-block-end: var(--space-lg);
}

.last-updated time {
  font-weight: 500;
}

/* ===== Print Bar ===== */
.print-bar {
  margin-block-start: var(--space-xl);
  padding-block-start: var(--space-lg);
  border-block-start: 1px solid var(--color-border);
  text-align: center;
}

@media print {
  .print-bar { display: none; }
}

/* ===== Checklist & Timeline ===== */
.timeline__phase {
  position: relative;
  padding-inline-start: var(--space-xl);
  margin-block-end: var(--space-xl);
  border-inline-start: 3px solid var(--color-primary);
}

.timeline__phase::before {
  content: '';
  position: absolute;
  inset-inline-start: -8px;
  inset-block-start: 0.5em;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--color-primary);
}

.timeline__heading {
  font-size: var(--font-size-lg);
  margin-block-end: var(--space-sm);
}

.checklist {
  list-style: none;
  padding: 0;
}

.checklist__item {
  padding: var(--space-xs) 0;
}

.checklist__item label {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
  cursor: pointer;
}

.checklist__item input[type="checkbox"] {
  margin-block-start: 0.3em;
  accent-color: var(--color-primary);
}

.checklist__item input:checked + span {
  text-decoration: line-through;
  opacity: 0.6;
}

.checklist-progress {
  margin-block: var(--space-lg);
}

.checklist-progress__bar {
  height: 8px;
  background: var(--color-surface);
  border-radius: var(--radius-sm, 4px);
  overflow: hidden;
  border: 1px solid var(--color-border);
}

.checklist-progress__fill {
  height: 100%;
  background: var(--color-primary);
  border-radius: var(--radius-sm, 4px);
  transition: width 0.3s ease;
  width: 0%;
}

.checklist-progress__text {
  display: block;
  margin-block-start: var(--space-xs);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

/* ===== Calculator ===== */
.calculator-form fieldset {
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-lg);
  margin-block-end: var(--space-lg);
}

.calculator-form legend {
  font-weight: 600;
  font-size: var(--font-size-lg);
  padding: 0 var(--space-sm);
}

.calculator-form label {
  display: block;
  font-weight: 600;
  margin-block: var(--space-sm) var(--space-xs);
}

.calculator-form input,
.calculator-form select {
  width: 100%;
  padding: var(--space-sm);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-sm);
  font-size: var(--font-size-base);
  background: var(--color-surface);
  color: var(--color-text);
  font-family: var(--font-family);
}

.calculator-form .hint {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-block-start: var(--space-xs);
}

.calculator-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-lg);
  margin-block-start: var(--space-lg);
}

.calculator-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-lg);
}

.calculator-card--highlight {
  border-color: var(--color-primary);
  text-align: center;
}

.calculator-savings {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-primary);
}

.calculator-card dl {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--space-xs) var(--space-md);
}

.calculator-card dd {
  text-align: end;
  margin: 0;
}

/* ===== Code Blocks ===== */
pre {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-sm);
  padding: var(--space-md);
  overflow-x: auto;
  font-size: var(--font-size-sm);
  line-height: 1.6;
}

code {
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.9em;
}

:not(pre) > code {
  background: var(--color-primary-light);
  padding: 0.15em 0.4em;
  border-radius: 3px;
}

/* ===== Comparison Table ===== */
.comparison-table {
  width: 100%;
  border-collapse: collapse;
  margin-block: var(--space-lg);
  font-size: var(--font-size-sm);
}

.comparison-table th,
.comparison-table td {
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--color-border);
  text-align: start;
}

.comparison-table th {
  background: var(--color-primary);
  color: #fff;
  font-weight: 600;
}

.comparison-table tr:nth-child(even) {
  background: var(--color-bg);
}

/* ===== Quick Reference Table ===== */
.quick-ref {
  width: 100%;
  border-collapse: collapse;
  margin-block: var(--space-lg);
  font-size: var(--font-size-sm);
}

.quick-ref th,
.quick-ref td {
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--color-border);
  text-align: start;
}

.quick-ref th {
  background: var(--color-bg);
  font-weight: 600;
}

.quick-ref code {
  font-size: 0.85em;
}