/* ==========================================================================
   eDiscovery Automation — site styles
   Light, professional palette: slate ink on near-white, indigo primary,
   teal & violet accents. Wide, fluid layout; elegant & responsive.
   ========================================================================== */

:root {
  --bg: #f7f9fc;
  --surface: #ffffff;
  --surface-2: #f1f5fb;
  --ink: #1f2937;
  --ink-soft: #374151;
  --muted: #5b6573;
  --muted-2: #7a8597;
  --border: #e3e8f0;
  --border-strong: #d4dbe8;

  --primary: #2b59c3;
  --primary-deep: #1e3a8a;
  --primary-soft: #eaf0fb;
  --accent-teal: #0e7c8a;
  --accent-teal-soft: #e1f4f4;
  --accent-violet: #6d28d9;
  --accent-violet-soft: #f0e9fd;

  --code-bg: #f5f7fb;
  --code-border: #e6ebf4;
  --inline-code-bg: #eef2fa;

  --shadow-sm: 0 1px 2px rgba(20, 35, 70, 0.06), 0 1px 3px rgba(20, 35, 70, 0.05);
  --shadow-md: 0 4px 16px rgba(20, 35, 70, 0.08), 0 2px 6px rgba(20, 35, 70, 0.05);
  --shadow-lg: 0 18px 48px rgba(20, 35, 70, 0.13);

  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 18px;

  --header-h: 66px;
  --container: 1340px;
  --measure: 78ch;

  --font-sans: "Segoe UI", Roboto, "Helvetica Neue", -apple-system, BlinkMacSystemFont,
    Arial, sans-serif;
  --font-mono: "SFMono-Regular", "JetBrains Mono", "Fira Code", Consolas, "Liberation Mono",
    Menlo, monospace;

  --transition: 160ms ease;
}

/* ---------- Reset / base --------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.7;
  letter-spacing: 0.005em;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img {
  max-width: 100%;
  height: auto;
}

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

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: clamp(1rem, 3vw, 2.5rem);
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--primary);
  color: #fff;
  padding: 0.6rem 1rem;
  border-radius: 0 0 var(--radius-sm) 0;
  z-index: 1000;
}
.skip-link:focus {
  left: 0;
}

:focus-visible {
  outline: 3px solid rgba(43, 89, 195, 0.45);
  outline-offset: 2px;
  border-radius: 3px;
}

/* ---------- Header / nav --------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: saturate(180%) blur(10px);
  -webkit-backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--ink);
  font-weight: 800;
}
.brand-mark {
  display: block;
  transition: transform var(--transition);
}
.brand:hover .brand-mark {
  transform: rotate(-6deg) scale(1.05);
}
.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.05;
}
.brand-name {
  font-size: 1.18rem;
  letter-spacing: -0.02em;
}
.brand-sub {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--primary);
}

.site-nav ul {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.5rem 0.85rem;
  border-radius: 999px;
  color: var(--ink-soft);
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  transition: background var(--transition), color var(--transition),
    border-color var(--transition);
}
.nav-link:hover {
  background: var(--surface-2);
  color: var(--primary-deep);
}
.nav-link.is-active {
  background: var(--primary-soft);
  color: var(--primary-deep);
  border-color: rgba(43, 89, 195, 0.18);
}
.nav-icon {
  display: inline-flex;
  width: 20px;
  height: 20px;
}
.nav-icon svg {
  width: 100%;
  height: 100%;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 40px;
  padding: 0 10px;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  cursor: pointer;
}
.nav-toggle-bar {
  display: block;
  height: 2.5px;
  border-radius: 2px;
  background: var(--ink);
  transition: transform var(--transition), opacity var(--transition);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) {
  transform: translateY(7.5px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) {
  transform: translateY(-7.5px) rotate(-45deg);
}

/* ---------- Main / footer layout ------------------------------------------ */
.site-main {
  flex: 1 0 auto;
}

.site-footer {
  flex-shrink: 0;
  margin-top: 4rem;
  background: #131a2e;
  color: #c7d0e0;
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  gap: 2.5rem;
  justify-content: space-between;
  padding-block: 2.6rem;
}
.footer-brand {
  display: flex;
  gap: 0.9rem;
  align-items: flex-start;
  max-width: 360px;
}
.footer-title {
  margin: 0;
  font-weight: 800;
  color: #fff;
}
.footer-tagline {
  margin: 0.2rem 0 0;
  font-size: 0.92rem;
  color: #9aa6bd;
}
.footer-heading {
  margin: 0 0 0.7rem;
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: #7e8aa3;
}
.footer-nav ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.5rem;
}
.footer-nav a {
  color: #c7d0e0;
  font-weight: 500;
}
.footer-nav a:hover {
  color: #fff;
  text-decoration: underline;
  text-underline-offset: 3px;
}
.footer-base {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-block: 1.1rem;
  font-size: 0.85rem;
  color: #8b97b0;
}
.footer-base p {
  margin: 0;
}

/* ---------- Hero ----------------------------------------------------------- */
.hero {
  position: relative;
  background: radial-gradient(
      1100px 460px at 18% -10%,
      var(--primary-soft),
      transparent 60%
    ),
    radial-gradient(900px 420px at 100% 0%, var(--accent-teal-soft), transparent 55%),
    linear-gradient(180deg, #ffffff, var(--bg));
  border-bottom: 1px solid var(--border);
  overflow: hidden;
}
.hero-inner {
  padding-block: clamp(2.6rem, 6vw, 5rem);
  text-align: center;
}
.hero-logo {
  margin: 0 auto 1.6rem;
}
.hero-logo img {
  width: min(520px, 86vw);
  height: auto;
  filter: drop-shadow(0 10px 26px rgba(30, 58, 138, 0.14));
}
.hero-title {
  margin: 0 auto 0.9rem;
  max-width: 20ch;
  font-size: clamp(1.9rem, 4.4vw, 3.1rem);
  line-height: 1.1;
  letter-spacing: -0.02em;
  font-weight: 800;
  background: linear-gradient(120deg, var(--primary-deep), var(--primary) 55%, var(--accent-teal));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-lede {
  margin: 0 auto;
  max-width: 60ch;
  font-size: clamp(1.05rem, 1.6vw, 1.28rem);
  color: var(--muted);
}
.hero-cta {
  margin-top: 2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}
.cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.85rem 1.3rem;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  color: var(--ink);
  text-align: left;
  transition: transform var(--transition), box-shadow var(--transition),
    border-color var(--transition);
}
.cta-btn:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--cta, var(--primary));
  color: var(--ink);
}
.cta-icon {
  display: inline-flex;
  width: 34px;
  height: 34px;
  padding: 5px;
  border-radius: 10px;
  background: color-mix(in srgb, var(--cta, var(--primary)) 12%, white);
}
.cta-icon svg {
  width: 100%;
  height: 100%;
}
.cta-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}
.cta-label {
  font-weight: 700;
}
.cta-go {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--cta, var(--primary));
}

/* ---------- Home sections -------------------------------------------------- */
.home-section {
  padding-block: clamp(2rem, 4vw, 3.4rem);
}
.section-title {
  font-size: clamp(1.5rem, 2.6vw, 2.1rem);
  letter-spacing: -0.015em;
  margin: 0 0 1.4rem;
  color: var(--ink);
}
.prose-intro {
  max-width: 72ch;
}
.prose-intro p {
  color: var(--ink-soft);
  margin: 0 0 1.1rem;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
  gap: 1.4rem;
}
.topic-card {
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  padding: 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-top: 4px solid var(--accent, var(--primary));
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), box-shadow var(--transition);
}
.topic-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}
.topic-card-head {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.topic-card-icon {
  display: inline-flex;
  width: 42px;
  height: 42px;
  padding: 7px;
  border-radius: 11px;
  background: color-mix(in srgb, var(--accent, var(--primary)) 12%, white);
  flex: none;
}
.topic-card-icon svg {
  width: 100%;
  height: 100%;
}
.topic-card-title {
  margin: 0;
  font-size: 1.12rem;
  line-height: 1.25;
}
.topic-card-title a {
  color: var(--ink);
}
.topic-card-title a:hover {
  color: var(--accent, var(--primary));
}
.topic-card-blurb {
  margin: 0;
  color: var(--muted);
  font-size: 0.96rem;
}
.topic-card-links {
  margin: 0.2rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.35rem;
}
.topic-card-links a {
  display: inline-block;
  font-size: 0.93rem;
  font-weight: 500;
  padding-left: 1.1rem;
  position: relative;
}
.topic-card-links a::before {
  content: "›";
  position: absolute;
  left: 0;
  color: var(--accent, var(--primary));
  font-weight: 700;
}
.topic-card-cta {
  margin-top: auto;
  padding-top: 0.6rem;
  font-weight: 700;
  color: var(--accent, var(--primary));
}

/* ---------- Article layout ------------------------------------------------- */
.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2.5rem;
  padding-block: 2rem 1rem;
}
@media (min-width: 1080px) {
  .article-layout {
    grid-template-columns: minmax(0, 1fr) 250px;
    align-items: start;
  }
}

.article {
  min-width: 0;
}
/* Content fills the full width of its column (container minus the TOC),
   rather than being pinned to a narrow measure. */
.article-body {
  max-width: none;
}

/* Breadcrumbs */
.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 0.5rem;
  align-items: center;
  margin: 0 0 1.4rem;
  padding: 0;
  list-style: none;
  font-size: 0.86rem;
  color: var(--muted);
}
.breadcrumbs li {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}
.breadcrumbs li + li::before {
  content: "/";
  color: var(--border-strong);
}
.breadcrumbs a {
  color: var(--muted);
  font-weight: 600;
}
.breadcrumbs a:hover {
  color: var(--primary);
}
.breadcrumbs [aria-current="page"] {
  color: var(--ink-soft);
  font-weight: 600;
}

/* Article typography */
.article-body h1 {
  font-size: clamp(1.85rem, 3.6vw, 2.7rem);
  line-height: 1.13;
  letter-spacing: -0.02em;
  margin: 0 0 1rem;
  background: linear-gradient(115deg, var(--primary-deep), var(--primary) 60%, var(--accent-teal));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.article-body h2 {
  font-size: clamp(1.4rem, 2.4vw, 1.85rem);
  line-height: 1.22;
  letter-spacing: -0.01em;
  margin: 2.6rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
  color: var(--ink);
}
.article-body h3 {
  font-size: clamp(1.18rem, 1.8vw, 1.4rem);
  margin: 2rem 0 0.7rem;
  color: var(--primary-deep);
}
.article-body h4 {
  font-size: 1.08rem;
  margin: 1.6rem 0 0.6rem;
  color: var(--ink);
}
.article-body :is(h1, h2, h3, h4) {
  scroll-margin-top: calc(var(--header-h) + 1.2rem);
}
.article-body p,
.article-body li {
  color: var(--ink-soft);
}
.article-body p {
  margin: 0 0 1.15rem;
}
.article-body ul,
.article-body ol {
  margin: 0 0 1.2rem;
  padding-left: 1.4rem;
}
.article-body li {
  margin: 0.35rem 0;
}
.article-body li::marker {
  color: var(--primary);
}
.article-body strong {
  color: var(--ink);
}
.article-body a {
  font-weight: 600;
  text-decoration: underline;
  text-decoration-color: rgba(43, 89, 195, 0.32);
  text-underline-offset: 2.5px;
  transition: color var(--transition), text-decoration-color var(--transition);
}
.article-body a:hover {
  text-decoration-color: var(--primary);
}
.article-body a.external-link::after {
  content: "↗";
  display: inline-block;
  margin-left: 0.15em;
  font-size: 0.78em;
  color: var(--muted-2);
}
.article-body blockquote {
  margin: 1.4rem 0;
  padding: 0.4rem 1.2rem;
  border-left: 4px solid var(--primary);
  background: var(--primary-soft);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--ink-soft);
}
.article-body hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2.4rem 0;
}

/* Inline code */
.article-body :not(pre) > code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--inline-code-bg);
  color: #324a8a;
  padding: 0.12em 0.42em;
  border-radius: 5px;
}

/* ---------- Code blocks ---------------------------------------------------- */
.code-block {
  margin: 1.5rem 0;
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.code-block figcaption {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.4rem 0.7rem 0.4rem 1rem;
  background: linear-gradient(180deg, #eef2fa, #e8eef8);
  border-bottom: 1px solid var(--code-border);
}
.code-lang {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}
.copy-btn {
  font: inherit;
  font-size: 0.78rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.28rem 0.7rem;
  color: var(--primary-deep);
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  cursor: pointer;
  transition: background var(--transition), color var(--transition),
    border-color var(--transition);
}
.copy-btn:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}
.copy-btn.copied {
  background: var(--accent-teal);
  color: #fff;
  border-color: var(--accent-teal);
}
.code-block pre {
  margin: 0;
  padding: 1.1rem 1.2rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.65;
  color: #283146;
  tab-size: 4;
}
.code-block code {
  font-family: inherit;
}

/* Prism light syntax theme (matched to palette) */
.token.comment,
.token.prolog,
.token.doctype,
.token.cdata {
  color: #8a93a6;
  font-style: italic;
}
.token.punctuation {
  color: #5b6573;
}
.token.namespace {
  opacity: 0.7;
}
.token.property,
.token.tag,
.token.boolean,
.token.number,
.token.constant,
.token.symbol,
.token.deleted {
  color: #b5277f;
}
.token.selector,
.token.attr-name,
.token.string,
.token.char,
.token.builtin,
.token.inserted {
  color: #0e7c8a;
}
.token.operator,
.token.entity,
.token.url,
.language-css .token.string,
.style .token.string {
  color: #9a5800;
}
.token.atrule,
.token.attr-value,
.token.keyword {
  color: #2b59c3;
  font-weight: 600;
}
.token.function,
.token.class-name {
  color: #6d28d9;
}
.token.regex,
.token.important,
.token.variable {
  color: #b5277f;
}

/* ---------- Tables --------------------------------------------------------- */
.table-wrap {
  margin: 1.5rem 0;
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  -webkit-overflow-scrolling: touch;
}
.table-wrap table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
  min-width: 460px;
}
.table-wrap th,
.table-wrap td {
  padding: 0.7rem 0.95rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.table-wrap thead th {
  background: var(--primary-soft);
  color: var(--primary-deep);
  font-weight: 700;
  position: sticky;
  top: 0;
}
.table-wrap tbody tr:nth-child(even) {
  background: var(--surface-2);
}
.table-wrap tbody tr:hover {
  background: color-mix(in srgb, var(--primary-soft) 60%, white);
}

/* ---------- Task lists (togglable checkboxes) ----------------------------- */
.article-body .contains-task-list {
  list-style: none; /* removes the leading dot in front of the checkbox */
  padding-left: 0;
}
.article-body .task-list-item {
  padding: 0.22rem 0;
  text-decoration-color: var(--muted-2);
}
.article-body .task-list-item::marker {
  content: "";
}
.article-body .task-list-item-checkbox {
  appearance: none;
  -webkit-appearance: none;
  width: 1.15em;
  height: 1.15em;
  vertical-align: -0.22em;
  margin-right: 0.55em;
  border: 2px solid var(--border-strong);
  border-radius: 5px;
  background: var(--surface);
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
  position: relative;
}
.article-body .task-list-item-checkbox:hover {
  border-color: var(--primary);
}
.article-body .task-list-item-checkbox:checked {
  background: var(--primary);
  border-color: var(--primary);
}
.article-body .task-list-item-checkbox:checked::after {
  content: "";
  position: absolute;
  left: 3.5px;
  top: 0.5px;
  width: 5px;
  height: 9px;
  border: solid #fff;
  border-width: 0 2.5px 2.5px 0;
  transform: rotate(45deg);
}
/* Strike-through the item text once its checkbox is checked. */
.article-body .task-list-item:has(> input.task-list-item-checkbox:checked) {
  text-decoration: line-through;
  color: var(--muted-2);
}
.article-body .task-list-item:has(> input.task-list-item-checkbox:checked) strong {
  color: var(--muted-2);
}

/* ---------- FAQ accordions ------------------------------------------------- */
.faq-accordion {
  margin: 0.5rem 0 1.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--surface);
  box-shadow: var(--shadow-sm);
}
.faq-accordion + .faq-accordion {
  margin-top: -0.5rem;
}
.faq-accordion > summary {
  list-style: none;
  cursor: pointer;
  padding: 1rem 1.2rem;
  font-weight: 700;
  color: var(--ink);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  transition: background var(--transition);
}
.faq-accordion > summary::-webkit-details-marker {
  display: none;
}
.faq-accordion > summary:hover {
  background: var(--surface-2);
}
.faq-accordion > summary::after {
  content: "+";
  font-size: 1.3rem;
  font-weight: 400;
  color: var(--primary);
  transition: transform var(--transition);
  flex: none;
}
.faq-accordion[open] > summary::after {
  transform: rotate(45deg);
}
.faq-accordion[open] > summary {
  border-bottom: 1px solid var(--border);
}
.faq-body {
  padding: 0.4rem 1.2rem 1.1rem;
}
.faq-body > :first-child {
  margin-top: 0.6rem;
}
.faq-body > :last-child {
  margin-bottom: 0;
}

/* ---------- Mermaid diagrams ---------------------------------------------- */
.mermaid-wrap {
  margin: 1.6rem 0;
  padding: 1.2rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  overflow-x: auto;
  text-align: center;
}
.mermaid-wrap pre.mermaid {
  margin: 0;
  background: none;
  border: none;
  visibility: hidden;
}
.mermaid-wrap pre.mermaid[data-processed] {
  visibility: visible;
}

/* ---------- KaTeX ---------------------------------------------------------- */
.katex {
  font-size: 1.04em;
}
.katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 0.4rem 0;
}

/* ---------- On-this-page TOC ---------------------------------------------- */
.toc {
  position: sticky;
  top: calc(var(--header-h) + 1.2rem);
  align-self: start;
  max-height: calc(100vh - var(--header-h) - 2.4rem);
  overflow-y: auto;
  font-size: 0.9rem;
  border-left: 2px solid var(--border);
  padding-left: 1.1rem;
}
.toc-title {
  margin: 0 0 0.7rem;
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted-2);
  font-weight: 700;
}
.toc-nav a {
  display: block;
  padding: 0.28rem 0;
  color: var(--muted);
  font-weight: 500;
  border-left: 2px solid transparent;
  margin-left: -1.1rem;
  padding-left: 1.1rem;
  line-height: 1.35;
}
.toc-nav a.lvl-3 {
  padding-left: 2rem;
  font-size: 0.85rem;
}
.toc-nav a:hover {
  color: var(--primary);
}
.toc-nav a.is-current {
  color: var(--primary-deep);
  border-left-color: var(--primary);
  font-weight: 700;
}
@media (max-width: 1079px) {
  .toc {
    display: none;
  }
}

/* ---------- Pager (prev / next) ------------------------------------------- */
.pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 1.6rem;
  border-top: 1px solid var(--border);
}
.pager-link {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 0.9rem 1.1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition), box-shadow var(--transition),
    border-color var(--transition);
}
.pager-link:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary);
}
.pager-next {
  text-align: right;
}
.pager-dir {
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--primary);
}
.pager-title {
  font-weight: 600;
  color: var(--ink);
}

/* ---------- Responsive: mobile nav ---------------------------------------- */
@media (max-width: 860px) {
  .nav-toggle {
    display: flex;
  }
  .site-nav {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    transform: translateY(-130%);
    transition: transform 220ms ease;
    max-height: calc(100vh - var(--header-h));
    overflow-y: auto;
  }
  .site-nav.is-open {
    transform: translateY(0);
  }
  .site-nav ul {
    flex-direction: column;
    align-items: stretch;
    gap: 0.2rem;
    padding: 0.8rem clamp(1rem, 3vw, 2.5rem) 1.2rem;
  }
  .nav-link {
    border-radius: var(--radius-sm);
    padding: 0.7rem 0.9rem;
    font-size: 1rem;
  }
  .pager {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  body {
    font-size: 16px;
  }
  .brand-sub {
    display: none;
  }
}

/* ---------- Diagram lightbox / fullscreen --------------------------------- */
.mermaid-wrap {
  position: relative;
  cursor: zoom-in;
}
.diagram-expand {
  position: absolute;
  top: 0.6rem;
  right: 0.6rem;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.32rem 0.65rem;
  font: inherit;
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--primary-deep);
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  box-shadow: var(--shadow-sm);
  cursor: zoom-in;
  opacity: 0;
  transition: opacity var(--transition), background var(--transition),
    color var(--transition), border-color var(--transition);
}
.mermaid-wrap:hover .diagram-expand,
.diagram-expand:focus-visible {
  opacity: 1;
}
.diagram-expand svg {
  width: 15px;
  height: 15px;
}
.diagram-expand:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}
@media (hover: none) {
  .diagram-expand {
    opacity: 1;
  }
}

.diagram-modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
}
.diagram-modal[hidden] {
  display: none;
}
.diagram-modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(17, 26, 46, 0.8);
  backdrop-filter: blur(3px);
  -webkit-backdrop-filter: blur(3px);
}
.diagram-modal-dialog {
  position: relative;
  margin: auto;
  width: min(96vw, 1400px);
  height: min(94vh, 900px);
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}
.diagram-modal-controls {
  display: flex;
  justify-content: flex-end;
  gap: 0.4rem;
  padding: 0.6rem;
  border-bottom: 1px solid var(--border);
  background: var(--surface-2);
}
.dm-btn {
  font: inherit;
  font-weight: 600;
  min-width: 2.2rem;
  padding: 0.3rem 0.7rem;
  color: var(--ink-soft);
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--transition), color var(--transition),
    border-color var(--transition);
}
.dm-btn:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}
.dm-close {
  font-size: 1.2rem;
  line-height: 1;
}
.diagram-modal-stage {
  flex: 1;
  overflow: hidden;
  position: relative;
  touch-action: none;
  cursor: grab;
  background: radial-gradient(circle, var(--border) 1px, transparent 1px) 0 0 /
      22px 22px,
    var(--surface);
}
.diagram-modal-stage.is-grabbing {
  cursor: grabbing;
}
.diagram-modal-canvas {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  transform-origin: center center;
  will-change: transform;
}
.diagram-modal-canvas svg {
  width: 100%;
  height: 100%;
}

/* ---------- Motion / print ------------------------------------------------ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}