:root {
  --color-bg: #f6f8fb;
  --color-surface: #ffffff;
  --color-text: #1f2933;
  --color-muted: #5f6f82;
  --color-border: #d9e2ec;
  --color-primary: #1f5f8b;
  --color-primary-dark: #174866;
  --color-accent: #d97706;

  --max-width: 1120px;
  --radius: 14px;
  --shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
}

/* =========================================================
   Base
   ========================================================= */

* {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  max-width: 100%;
  overflow-x: hidden;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  max-width: 100%;
  overflow-x: hidden;
}

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

a:hover,
a:focus {
  text-decoration: underline;
}

.container {
  width: min(100% - 32px, var(--max-width));
  margin-inline: auto;
  max-width: 100%;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 8px;
  background: var(--color-primary);
  color: #fff;
  padding: 8px 12px;
  z-index: 1000;
}

.skip-link:focus {
  left: 8px;
}

/* =========================================================
   Header / Navigation
   ========================================================= */

.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 64px;
}

.site-logo {
  font-weight: 800;
  font-size: 1.35rem;
  color: var(--color-text);
}

.site-logo:hover,
.site-logo:focus {
  text-decoration: none;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.site-nav a {
  color: var(--color-muted);
  font-weight: 700;
  font-size: 0.95rem;
}

.site-nav a.active,
.site-nav a:hover,
.site-nav a:focus {
  color: var(--color-primary);
}

/* =========================================================
   Main layout
   ========================================================= */

.site-main {
  padding: clamp(1.75rem, 3vw, 2.5rem) 0 48px;
}

.hero {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: clamp(2rem, 4vw, 3rem);
  max-width: 100%;
}

.hero h1 {
  margin: 0 0 1.1rem;
  font-size: clamp(2.25rem, 5vw, 3.6rem);
  line-height: 1.08;
  letter-spacing: -0.035em;
  overflow-wrap: anywhere;
}

.hero p {
  margin: 0;
  max-width: 72ch;
  color: var(--color-muted);
  font-size: clamp(1.05rem, 2.1vw, 1.35rem);
  line-height: 1.55;
}

.section {
  margin-top: clamp(2rem, 4vw, 3rem);
  max-width: 100%;
}

.section h2 {
  margin-top: 0;
  margin-bottom: 16px;
  font-size: clamp(1.65rem, 4vw, 2.25rem);
  line-height: 1.15;
  overflow-wrap: anywhere;
}

/* =========================================================
   Cards
   ========================================================= */

.card-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
}

.card h3 {
  margin-top: 0;
  margin-bottom: 10px;
  font-size: 1.2rem;
}

.card p {
  color: var(--color-muted);
  margin-bottom: 0;
}

/* =========================================================
   Guide pages
   ========================================================= */

.guide-page {
  width: min(100% - 32px, 960px);
  margin-inline: auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 34px;
  max-width: 100%;
  overflow-wrap: anywhere;
  word-break: normal;
}

.guide-header {
  margin-bottom: 26px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--color-border);
}

.guide-header h1 {
  margin: 0 0 14px;
  font-size: clamp(2rem, 4vw, 3rem);
  line-height: 1.08;
  letter-spacing: -0.03em;
  overflow-wrap: anywhere;
}

.lead,
.guide-header .lead {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--color-muted);
  line-height: 1.55;
  max-width: 72ch;
}

.guide-page section {
  margin-top: 28px;
}

.guide-page h2 {
  margin-top: 0;
  margin-bottom: 14px;
  font-size: clamp(1.45rem, 2.6vw, 1.85rem);
  line-height: 1.25;
  overflow-wrap: anywhere;
}

.guide-page h3 {
  margin-top: 22px;
  margin-bottom: 8px;
  font-size: clamp(1.1rem, 2.3vw, 1.3rem);
  line-height: 1.3;
}

.guide-page p {
  margin-top: 0;
  margin-bottom: 14px;
  overflow-wrap: anywhere;
}

.guide-page ol,
.guide-page ul {
  padding-left: 1.35rem;
}

.guide-page li {
  margin-bottom: 12px;
  overflow-wrap: anywhere;
}

.guide-page strong {
  color: var(--color-text);
}

/* =========================================================
   Callout boxes
   ========================================================= */

.quick-definition {
  background: #eef6fb;
  border-left: 5px solid var(--color-primary);
  border-radius: 10px;
  padding: 18px 22px;
  margin: 26px 0;
  max-width: 100%;
  overflow-x: auto;
}

.quick-definition h2 {
  margin-top: 0;
}

.warning-box {
  background: #fff7ed;
  border-left: 5px solid var(--color-accent);
  border-radius: 10px;
  padding: 18px 22px;
  margin: 26px 0;
  max-width: 100%;
  overflow-x: auto;
}

.quick-definition p:last-child,
.warning-box p:last-child,
.guide-page .quick-definition p:last-child,
.guide-page .warning-box p:last-child {
  margin-bottom: 0;
}

/* =========================================================
   Tables
   ========================================================= */

.guide-page table {
  width: 100%;
  border-collapse: collapse;
  margin: 18px 0 24px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  overflow: hidden;
}

.guide-page th,
.guide-page td {
  border: 1px solid var(--color-border);
  padding: 12px 14px;
  text-align: left;
  vertical-align: top;
}

.guide-page th {
  background: #eef6fb;
  color: var(--color-text);
  font-weight: 800;
}

.guide-page tr:nth-child(even) td {
  background: #fafcff;
}

/* =========================================================
   Practice question lists
   ========================================================= */

.guide-page ol[type="A"] {
  margin-top: 8px;
  margin-bottom: 10px;
}

.guide-page ol[type="A"] li {
  margin-bottom: 4px;
}

/* =========================================================
   Page lists / section indexes
   ========================================================= */

.page-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr));
  gap: 14px;
  padding-left: 0;
  list-style: none;
}

.page-list li {
  margin: 0;
  padding: 16px 18px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: var(--color-surface);
  box-shadow: 0 3px 12px rgba(15, 23, 42, 0.04);
}

.page-list li:hover,
.page-list li:focus-within {
  border-color: var(--color-primary);
  background: #f3f9fd;
}

.page-list a {
  display: inline;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  text-decoration: none;
  font-weight: 700;
}

.page-list a:hover,
.page-list a:focus {
  text-decoration: underline;
}

/* =========================================================
   Footer
   ========================================================= */

.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-muted);
  padding: 28px 0;
  font-size: 0.95rem;
}

/* =========================================================
   Responsive
   ========================================================= */

@media (max-width: 900px) {
  .header-inner {
    gap: 18px;
  }

  .site-nav,
  nav {
    flex-wrap: wrap;
  }
}

@media (max-width: 820px) {
  .header-inner {
    align-items: flex-start;
    flex-direction: column;
    padding: 18px 0;
  }

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

  .hero {
    padding: 28px;
  }

  .guide-page {
    width: min(100% - 24px, 960px);
    padding: 28px;
  }
}

@media (max-width: 640px) {
  .container {
    width: 100%;
    padding-left: 18px;
    padding-right: 18px;
  }

  .site-main {
    padding-top: 1.5rem;
  }

  .hero {
    padding: 1.75rem 22px;
  }

  .guide-page {
    width: calc(100% - 24px);
    padding: 26px 22px;
  }

  .hero h1 {
    font-size: clamp(2rem, 9vw, 2.7rem);
    line-height: 1.08;
  }

  .guide-header h1 {
    font-size: clamp(1.85rem, 8vw, 2.5rem);
    line-height: 1.08;
  }

  .hero p,
  .guide-header .lead,
  .lead {
    font-size: 1.05rem;
    line-height: 1.55;
  }

  .quick-definition,
  .warning-box {
    padding: 20px;
  }

  .guide-page ol,
  .guide-page ul {
    padding-left: 1.15rem;
  }

  .guide-page li {
    padding-right: 4px;
  }

  .guide-page table,
  .guide-page thead,
  .guide-page tbody,
  .guide-page th,
  .guide-page td,
  .guide-page tr {
    display: block;
  }

  .guide-page thead {
    display: none;
  }

  .guide-page tr {
    border-bottom: 1px solid var(--color-border);
  }

  .guide-page td {
    border-left: 0;
    border-right: 0;
  }
}

@media (max-width: 420px) {
  .container {
    padding-left: 14px;
    padding-right: 14px;
  }

  .hero {
    padding-left: 18px;
    padding-right: 18px;
  }

  .guide-page {
    width: calc(100% - 16px);
    padding-left: 18px;
    padding-right: 18px;
  }

  .hero h1 {
    font-size: clamp(1.9rem, 11vw, 2.45rem);
  }

  .guide-header h1 {
    font-size: clamp(1.75rem, 10vw, 2.25rem);
  }

  .guide-page h2,
  .section h2 {
    font-size: 1.55rem;
  }
}
/* =========================================================
   Practice answer reveal controls
   ========================================================= */

.answer-toggle {
  margin: 12px 0 18px;
}

.answer-toggle-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 9px 14px;
  border: 1px solid var(--color-primary);
  border-radius: 10px;
  background: var(--color-primary);
  color: #ffffff;
  font-weight: 800;
  font-family: inherit;
  font-size: 0.95rem;
  cursor: pointer;
}

.answer-toggle-button:hover,
.answer-toggle-button:focus {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
}

.answer-toggle-panel {
  margin-top: 12px;
  padding: 14px 16px;
  border-left: 5px solid var(--color-primary);
  border-radius: 10px;
  background: #eef6fb;
}

.answer-toggle-panel p:last-child {
  margin-bottom: 0;
}

/* =========================================================
   Interactive quiz engine
   ========================================================= */

.quiz-app {
  margin-top: 24px;
}

.quiz-form {
  display: grid;
  gap: 22px;
}

.quiz-question {
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 20px;
  background: #ffffff;
}

.quiz-question legend {
  font-weight: 800;
  line-height: 1.45;
  margin-bottom: 12px;
}

.quiz-question legend span {
  color: var(--color-primary);
}

.quiz-choice {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 10px 12px;
  margin: 8px 0;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  cursor: pointer;
}

.quiz-choice:hover,
.quiz-choice:focus-within {
  background: #f3f9fd;
  border-color: var(--color-primary);
}

.quiz-choice input {
  margin-top: 0.3rem;
}

.quiz-explanation {
  margin-top: 14px;
  padding: 14px 16px;
  border-left: 5px solid var(--color-primary);
  border-radius: 10px;
  background: #eef6fb;
}

.quiz-question.is-correct {
  border-color: #15803d;
}

.quiz-question.is-incorrect,
.quiz-question.is-unanswered {
  border-color: #b45309;
}

.quiz-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.quiz-submit,
.quiz-restart {
  min-height: 42px;
  padding: 10px 16px;
  border: 1px solid var(--color-primary);
  border-radius: 10px;
  background: var(--color-primary);
  color: #ffffff;
  font-family: inherit;
  font-weight: 800;
  cursor: pointer;
}

.quiz-restart {
  background: #ffffff;
  color: var(--color-primary);
}

.quiz-submit:hover,
.quiz-submit:focus {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
}

.quiz-restart:hover,
.quiz-restart:focus {
  background: #f3f9fd;
}

.quiz-submit:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.quiz-result {
  margin: 0;
  font-weight: 800;
}

/* =========================================================
   Breadcrumbs / section context
   ========================================================= */

.breadcrumbs {
  width: min(100% - 32px, var(--max-width));
  margin: 0 auto 18px;
  color: var(--color-muted);
  font-size: 0.95rem;
  font-weight: 700;
}

.breadcrumbs a {
  color: var(--color-primary);
}

.breadcrumb-separator {
  display: inline-block;
  margin: 0 8px;
  color: var(--color-muted);
}

.breadcrumbs span[aria-current="page"] {
  color: var(--color-muted);
}

.guide-page + .breadcrumbs {
  margin-top: 0;
}

@media (max-width: 640px) {
  .breadcrumbs {
    width: calc(100% - 32px);
    margin-bottom: 14px;
    font-size: 0.9rem;
  }
}

/* =========================================================
   Learn section previous/next flow navigation
   ========================================================= */

.learn-flow-nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 38px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border);
}

.learn-flow-card {
  display: block;
  padding: 16px 18px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: var(--color-surface);
  text-decoration: none;
}

.learn-flow-card span {
  display: block;
  margin-bottom: 4px;
  color: var(--color-muted);
  font-size: 0.9rem;
  font-weight: 700;
}

.learn-flow-card strong {
  display: block;
  color: var(--color-primary);
  font-size: 1.02rem;
  line-height: 1.35;
}

.learn-flow-card:hover,
.learn-flow-card:focus {
  border-color: var(--color-primary);
  background: #f3f9fd;
  text-decoration: none;
}

.learn-flow-disabled {
  opacity: 0.65;
}

.learn-flow-disabled strong {
  color: var(--color-muted);
}

.learn-flow-next {
  text-align: right;
}

@media (max-width: 640px) {
  .learn-flow-nav {
    grid-template-columns: 1fr;
  }

  .learn-flow-next {
    text-align: left;
  }
}

/* =========================================================
   Site-wide educational disclaimer
   ========================================================= */

.site-disclaimer {
  width: min(100% - 32px, var(--max-width));
  margin: 0 auto 18px;
  padding: 14px 16px;
  border: 1px solid var(--color-border);
  border-left: 5px solid var(--color-accent);
  border-radius: 10px;
  background: #fff7ed;
  color: var(--color-muted);
}

.site-disclaimer p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.5;
}

@media (max-width: 640px) {
  .site-disclaimer {
    width: calc(100% - 32px);
    margin-bottom: 16px;
  }
}

/* ============================================================
   Sticky site header
   Keeps main navigation visible while scrolling.
   ============================================================ */

.site-header,
header.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border, #dbe3ea);
  box-shadow: 0 2px 10px rgba(15, 23, 42, 0.06);
}


/* ============================================================
   Fixed site header - final override
   Keeps navigation visible at all scroll positions.
   ============================================================ */

body {
  padding-top: 72px;
}

.site-header {
  position: fixed !important;
  top: 0 !important;
  left: 0 !important;
  right: 0 !important;
  z-index: 9999 !important;
  background: rgba(255, 255, 255, 0.98) !important;
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border, #dbe3ea);
  box-shadow: 0 2px 10px rgba(15, 23, 42, 0.08);
}

@media (max-width: 700px) {
  body {
    padding-top: 96px;
  }
}


/* ============================================================
   v12a Navigation Redesign
   Content hubs are grouped into four top-level header menus so
   the header remains usable as the site grows.
   ============================================================ */

.header-inner {
  position: relative;
}

.mega-nav {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  justify-content: flex-end;
  gap: 6px;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 12px;
  border-radius: 999px;
  color: var(--color-muted);
  font-weight: 800;
  font-size: 0.95rem;
  text-decoration: none;
  white-space: nowrap;
}

.nav-link::after {
  content: "";
  width: 0.45rem;
  height: 0.45rem;
  margin-left: 0.45rem;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: translateY(-2px) rotate(45deg);
  opacity: 0.7;
}

.nav-item.active > .nav-link,
.nav-item:hover > .nav-link,
.nav-item:focus-within > .nav-link {
  color: var(--color-primary);
  background: #eef7fb;
  text-decoration: none;
}

.mega-panel {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(210px, 1fr));
  gap: 18px;
  min-width: min(92vw, 520px);
  padding: 20px;
  border: 1px solid var(--color-border);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.99);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.16);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  pointer-events: none;
  transition: opacity 140ms ease, transform 140ms ease, visibility 140ms ease;
}

.mega-panel-wide {
  grid-template-columns: repeat(3, minmax(190px, 1fr));
  min-width: min(92vw, 760px);
}

.has-mega:hover .mega-panel,
.has-mega:focus-within .mega-panel {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
  pointer-events: auto;
}

.mega-column {
  display: grid;
  align-content: start;
  gap: 8px;
}

.mega-heading {
  margin: 0 0 4px;
  color: var(--color-text);
  font-size: 0.82rem;
  font-weight: 900;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.mega-column a {
  display: block;
  padding: 8px 10px;
  border-radius: 10px;
  color: var(--color-muted);
  font-size: 0.94rem;
  font-weight: 700;
  line-height: 1.25;
  text-decoration: none;
}

.mega-column a:hover,
.mega-column a:focus {
  color: var(--color-primary);
  background: #f3f9fd;
  text-decoration: none;
}

.mega-column sub {
  font-size: 0.68em;
  line-height: 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(180px, 1.4fr) repeat(4, minmax(140px, 1fr));
  gap: 24px;
  align-items: start;
}

.footer-title {
  margin: 0 0 8px;
  color: var(--color-text);
  font-weight: 900;
}

.footer-grid a {
  display: block;
  margin: 0 0 6px;
  color: var(--color-muted);
  font-weight: 700;
}

.footer-grid a:hover,
.footer-grid a:focus {
  color: var(--color-primary);
}

@media (max-width: 980px) {
  body {
    padding-top: 116px;
  }

  .header-inner {
    align-items: flex-start;
    flex-direction: column;
    justify-content: center;
    gap: 8px;
    min-height: 104px;
    padding: 10px 0;
  }

  .mega-nav {
    width: 100%;
    justify-content: flex-start;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .mega-panel,
  .mega-panel-wide {
    left: 0;
    right: auto;
    grid-template-columns: repeat(2, minmax(180px, 1fr));
    min-width: min(92vw, 620px);
  }
}

@media (max-width: 700px) {
  body {
    padding-top: 148px;
  }

  .header-inner {
    min-height: 136px;
  }

  .mega-nav {
    flex-wrap: wrap;
    overflow: visible;
    gap: 4px;
  }

  .nav-link {
    min-height: 36px;
    padding: 0 10px;
    font-size: 0.9rem;
  }

  .mega-panel,
  .mega-panel-wide {
    position: fixed;
    top: 132px;
    left: 16px;
    right: 16px;
    grid-template-columns: 1fr;
    min-width: 0;
    max-height: calc(100vh - 150px);
    overflow-y: auto;
  }

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

@media (max-width: 520px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}


/* ============================================================
   v12b Navigation Rescue
   Replace failed mega-menu with a compact, reliable header.
   Major hubs are visible in the header; detailed navigation lives on hub pages.
   ============================================================ */
body {
  padding-top: 72px !important;
}

.site-header {
  position: fixed !important;
  top: 0 !important;
  left: 0 !important;
  right: 0 !important;
  z-index: 9999 !important;
  background: rgba(255, 255, 255, 0.98) !important;
  border-bottom: 1px solid var(--color-border, #dbe3ea) !important;
  box-shadow: 0 2px 10px rgba(15, 23, 42, 0.08) !important;
}

.header-inner {
  min-height: 64px !important;
  display: flex !important;
  align-items: center !important;
  justify-content: space-between !important;
  gap: 24px !important;
  padding-top: 0 !important;
  padding-bottom: 0 !important;
}

.site-logo {
  flex: 0 0 auto;
  white-space: nowrap;
}

.compact-nav {
  display: flex !important;
  align-items: center !important;
  justify-content: flex-end !important;
  flex-wrap: nowrap !important;
  gap: 6px !important;
  overflow-x: auto;
  scrollbar-width: thin;
}

.compact-nav a {
  display: inline-flex !important;
  align-items: center !important;
  min-height: 38px !important;
  padding: 0 10px !important;
  border-radius: 999px !important;
  color: var(--color-muted) !important;
  font-size: 0.92rem !important;
  font-weight: 800 !important;
  line-height: 1 !important;
  white-space: nowrap !important;
  text-decoration: none !important;
}

.compact-nav a.active,
.compact-nav a:hover,
.compact-nav a:focus {
  color: var(--color-primary) !important;
  background: #eef7fb !important;
  text-decoration: none !important;
}

.mega-panel,
.mega-panel-wide {
  display: none !important;
}

@media (max-width: 980px) {
  body {
    padding-top: 116px !important;
  }

  .header-inner {
    min-height: 104px !important;
    align-items: flex-start !important;
    flex-direction: column !important;
    justify-content: center !important;
    gap: 8px !important;
    padding: 10px 0 !important;
  }

  .compact-nav {
    width: 100% !important;
    justify-content: flex-start !important;
    padding-bottom: 4px !important;
  }
}

@media (max-width: 640px) {
  body {
    padding-top: 148px !important;
  }

  .header-inner {
    min-height: 136px !important;
  }

  .compact-nav {
    flex-wrap: wrap !important;
    overflow: visible !important;
    gap: 4px !important;
  }

  .compact-nav a {
    min-height: 34px !important;
    padding: 0 9px !important;
    font-size: 0.88rem !important;
  }
}


/* =========================================================
   v15a operational UX and discoverability systems
   ========================================================= */

.eyebrow {
  margin: 0 0 8px;
  color: var(--color-accent);
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.operational-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(240px, 0.8fr);
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: center;
}

.operational-hero .hero-copy p:not(.eyebrow) {
  margin-top: 0.9rem;
}

.hero-actions {
  display: grid;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 16px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: #f8fbfd;
  color: var(--color-primary);
  font-weight: 900;
  text-align: center;
}

.btn:hover,
.btn:focus {
  border-color: var(--color-primary);
  background: #eef6fb;
  text-decoration: none;
}

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

.btn-primary:hover,
.btn-primary:focus {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: #ffffff;
}

.section-heading-row {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 16px;
}

.section-heading-row h2 {
  margin-bottom: 0;
}

.text-link {
  font-weight: 900;
  white-space: nowrap;
}

.operational-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.operation-card {
  display: flex;
  flex-direction: column;
  min-height: 100%;
  padding: 22px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  box-shadow: var(--shadow);
}

.operation-card.priority-card {
  border-color: rgba(31, 95, 139, 0.38);
  background: linear-gradient(180deg, #ffffff 0%, #f2f8fc 100%);
}

.operation-card h3 {
  margin: 0 0 8px;
  font-size: 1.15rem;
}

.operation-card p {
  margin: 0 0 14px;
  color: var(--color-muted);
}

.operation-card ul {
  margin: auto 0 0;
  padding-left: 1.1rem;
}

.operation-card li {
  margin-bottom: 6px;
}

.quick-access-band {
  margin-top: clamp(2rem, 4vw, 3rem);
  padding: 22px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: #ffffff;
  box-shadow: var(--shadow);
}

.quick-access-band h2 {
  margin-top: 0;
}

.quick-chip-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.quick-chip-grid a,
.workflow-grid a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 8px 12px;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: #f8fbfd;
  font-weight: 800;
}

.quick-chip-grid a:hover,
.quick-chip-grid a:focus,
.workflow-grid a:hover,
.workflow-grid a:focus {
  background: #eef6fb;
  border-color: var(--color-primary);
  text-decoration: none;
}

.balance-card {
  padding: clamp(1.5rem, 4vw, 2.5rem);
  border: 1px solid #f0d6ad;
  border-radius: var(--radius);
  background: #fff9f0;
  box-shadow: var(--shadow);
}

.balance-card h2 {
  margin-top: 0;
}

.workflow-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.section-nav {
  width: min(100% - 32px, var(--max-width));
  margin: 0 auto 22px;
  padding: 14px 16px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: #ffffff;
  box-shadow: 0 3px 12px rgba(15, 23, 42, 0.04);
}

.section-nav-title {
  display: block;
  margin-bottom: 8px;
  color: var(--color-muted);
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.section-nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.section-nav-links a {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  padding: 6px 10px;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: #f8fbfd;
  color: var(--color-primary);
  font-size: 0.92rem;
  font-weight: 800;
}

.section-nav-links a.active,
.section-nav-links a:hover,
.section-nav-links a:focus {
  border-color: var(--color-primary);
  background: #eef6fb;
  text-decoration: none;
}

.related-panel {
  width: min(100% - 32px, var(--max-width));
  margin: clamp(2rem, 4vw, 3rem) auto 0;
  padding: 24px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: #ffffff;
  box-shadow: var(--shadow);
}

.related-panel h2 {
  margin-top: 0;
  font-size: clamp(1.35rem, 3vw, 1.8rem);
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.related-card {
  display: block;
  padding: 14px 16px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: #f8fbfd;
}

.related-card:hover,
.related-card:focus {
  border-color: var(--color-primary);
  background: #eef6fb;
  text-decoration: none;
}

.related-card span {
  display: block;
  font-weight: 900;
}

.related-card small {
  display: block;
  margin-top: 6px;
  color: var(--color-muted);
  line-height: 1.45;
}

.site-map-page .page-list {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 220px), 1fr));
}

@media (max-width: 1040px) {
  .operational-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .related-grid,
  .workflow-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 820px) {
  .operational-hero {
    grid-template-columns: 1fr;
  }

  .section-heading-row {
    align-items: flex-start;
    flex-direction: column;
  }

  .text-link {
    white-space: normal;
  }

  .operational-grid,
  .related-grid,
  .workflow-grid {
    grid-template-columns: 1fr;
  }
}

@media (min-width: 1100px) {
  .section-nav {
    position: sticky;
    top: 10px;
    z-index: 5;
  }
}

/* =========================================================
   v15b system-behavior diagrams
   ========================================================= */

.system-diagram {
  margin: 28px 0;
  padding: 20px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: #f8fbfd;
}

.diagram-title {
  margin-bottom: 14px;
  color: var(--color-muted);
  font-size: 0.82rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.isolation-diagram,
.flow-diagram {
  display: grid;
  gap: 12px;
  align-items: stretch;
}

.isolation-diagram {
  grid-template-columns: 1.1fr 0.85fr 1.1fr;
}

.isolation-diagram .pipe,
.isolation-diagram .flange,
.isolation-diagram .bypass,
.flow-diagram > div {
  padding: 14px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: var(--color-surface);
  font-weight: 800;
  text-align: center;
}

.isolation-diagram .protected {
  border-color: #7fb3d5;
}

.isolation-diagram .grounded {
  border-color: #a3b18a;
}

.isolation-diagram .flange {
  border-style: dashed;
  background: #fffdf5;
}

.isolation-diagram .bypass {
  grid-column: 1 / -1;
  background: #f4f7fb;
  color: var(--color-primary-dark);
}

.flow-diagram.three-step {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.system-diagram small {
  display: block;
  margin-top: 4px;
  color: var(--color-muted);
  font-weight: 600;
  line-height: 1.35;
}

@media (max-width: 760px) {
  .isolation-diagram,
  .flow-diagram.three-step {
    grid-template-columns: 1fr;
  }

  .isolation-diagram .bypass {
    grid-column: auto;
  }
}


/* =========================================================
   Technical Practice Guide Pages
   ========================================================= */

.technical-practice-guide .guide-header {
  margin: 32px 0 24px;
}

.technical-practice-guide .guide-header h1 {
  max-width: none;
}

.technical-practice-guide .lead {
  max-width: none;
}

.guide-layout {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 28px;
  align-items: start;
}

.guide-sidebar {
  position: relative;
}

.guide-nav-card {
  position: sticky;
  top: 18px;
  display: grid;
  gap: 8px;
  padding: 18px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.guide-nav-card h2 {
  margin: 0 0 8px;
  font-size: 1rem;
}

.guide-nav-card a {
  display: block;
  padding: 6px 0;
  font-size: 0.93rem;
  font-weight: 700;
  color: var(--color-muted);
}

.guide-main {
  min-width: 0;
}

.content-block {
  margin-bottom: 32px;
  padding: 24px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.content-block > h2:first-child {
  margin-top: 0;
}

.callout {
  margin: 20px 0;
  padding: 16px 18px;
  border-left: 5px solid var(--color-primary);
  background: #f8fafc;
  border-radius: 10px;
}

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

.callout-info {
  border-left-color: var(--color-primary);
}

.callout-accent {
  border-left-color: var(--color-accent);
}

.callout-warning {
  border-left-color: #d97706;
  background: #fff7ed;
}

.callout-danger {
  border-left-color: #dc2626;
  background: #fef2f2;
}

.callout-success {
  border-left-color: #16a34a;
  background: #f0fdf4;
}

.tag-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 16px 0 20px;
}

.tag-grid span {
  display: inline-flex;
  align-items: center;
  padding: 7px 11px;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  background: #f8fafc;
  font-weight: 700;
  color: var(--color-muted);
  font-size: 0.92rem;
}

.procedure-list {
  display: grid;
  gap: 10px;
  padding-left: 24px;
}

.procedure-list li {
  padding-left: 4px;
}

.practice-question,
.worked-step {
  margin: 18px 0;
  padding: 18px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: #f8fafc;
}

.practice-question h3,
.worked-step h3 {
  margin-top: 0;
}

.formula-block,
.formula-card {
  margin: 18px 0;
  padding: 18px;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  background: #f8fafc;
}

.formula-block p {
  margin: 0;
  font-size: 1.15rem;
  font-weight: 800;
}

.table-wrapper {
  overflow-x: auto;
}

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

  .guide-nav-card {
    position: static;
  }
}


.ca-unit-nowrap {
  white-space: nowrap;
}