:root {
  --bb-blue-950: #041b3d;
  --bb-blue-900: #06295c;
  --bb-blue-800: #003f88;
  --bb-blue-700: #0756a5;
  --bb-blue-100: #eaf2ff;
  --bb-yellow: #ffe000;
  --bb-yellow-strong: #f7c900;
  --bb-yellow-soft: #fff8c7;
  --ink: #16243a;
  --muted: #5d6b7d;
  --line: #d8e2ef;
  --surface: #ffffff;
  --surface-soft: #f4f7fb;
  --page: #eef3f9;
  --shadow: 0 18px 52px rgba(4, 31, 73, 0.11);
  --shadow-soft: 0 9px 28px rgba(4, 31, 73, 0.08);
  --radius: 22px;
  --max: 1480px;
  --reading: 920px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 116px;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(0, 63, 136, 0.05), transparent 12%, transparent 88%, rgba(0, 63, 136, 0.05)),
    var(--page);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.72;
  text-rendering: optimizeLegibility;
}

body.menu-open {
  overflow: hidden;
}

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

a {
  color: inherit;
}

p {
  margin: 0 0 1.15rem;
}

.skip-link {
  position: fixed;
  left: 18px;
  top: -100px;
  z-index: 1000;
  padding: 12px 17px;
  color: var(--bb-blue-950);
  background: var(--bb-yellow);
  border-radius: 0 0 10px 10px;
  font-weight: 800;
  text-decoration: none;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 0;
}

.portal-strip {
  color: #ffffff;
  background: var(--bb-blue-950);
  font-size: 0.84rem;
}

.portal-strip-inner {
  width: min(calc(100% - 48px), var(--max));
  min-height: 38px;
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.portal-strip p {
  margin: 0;
}

.portal-strip strong,
.portal-strip-secondary {
  color: var(--bb-yellow);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.97);
  border-bottom: 1px solid var(--line);
  box-shadow: 0 5px 22px rgba(4, 31, 73, 0.07);
  backdrop-filter: blur(14px);
}

.header-inner {
  width: min(calc(100% - 48px), var(--max));
  min-height: 92px;
  margin-inline: auto;
  display: flex;
  align-items: center;
  gap: 30px;
}

.brand {
  min-width: 310px;
  display: flex;
  align-items: center;
  gap: 14px;
  color: var(--bb-blue-950);
  text-decoration: none;
}

.brand img {
  width: 58px;
  height: 58px;
  flex: 0 0 58px;
  object-fit: cover;
  background: var(--bb-yellow);
  border: 1px solid rgba(4, 31, 73, 0.12);
  border-radius: 14px;
  box-shadow: 0 7px 20px rgba(4, 31, 73, 0.11);
}

.brand span {
  min-width: 0;
  display: flex;
  flex-direction: column;
}

.brand strong {
  font-size: 1.07rem;
  line-height: 1.2;
  letter-spacing: -0.01em;
}

.brand small {
  margin-top: 4px;
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.35;
}

.main-nav {
  margin-left: auto;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 4px;
}

.main-nav a {
  position: relative;
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  padding: 10px 11px;
  color: var(--ink);
  border-radius: 12px;
  font-size: 0.86rem;
  font-weight: 760;
  line-height: 1.25;
  text-align: center;
  text-decoration: none;
  transition: color 0.18s ease, background 0.18s ease, transform 0.18s ease;
}

.main-nav a::after {
  content: "";
  position: absolute;
  left: 13px;
  right: 13px;
  bottom: 4px;
  height: 3px;
  background: var(--bb-yellow-strong);
  border-radius: 999px;
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 0.18s ease;
}

.main-nav a:hover {
  color: var(--bb-blue-800);
  background: var(--bb-blue-100);
  transform: translateY(-1px);
}

.main-nav a:hover::after,
.main-nav a[aria-current="page"]::after {
  transform: scaleX(1);
}

.main-nav a[aria-current="page"] {
  color: var(--bb-blue-900);
  background: var(--bb-blue-100);
}

.menu-toggle {
  display: none;
  min-height: 44px;
  padding: 10px 15px;
  color: #ffffff;
  background: var(--bb-blue-900);
  border: 0;
  border-radius: 11px;
  font: inherit;
  font-weight: 800;
  cursor: pointer;
}

.menu-toggle::before {
  content: "☰";
  margin-right: 8px;
  color: var(--bb-yellow);
}

.hero {
  position: relative;
  overflow: hidden;
  color: #ffffff;
  background: linear-gradient(128deg, var(--bb-blue-950) 0%, var(--bb-blue-900) 53%, var(--bb-blue-700) 100%);
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 84% 14%, rgba(255, 224, 0, 0.18), transparent 31%),
    linear-gradient(112deg, transparent 0 63%, rgba(255, 255, 255, 0.045) 63% 64%, transparent 64%);
  pointer-events: none;
}

.hero-inner {
  position: relative;
  width: min(calc(100% - 72px), var(--max));
  min-height: 590px;
  margin-inline: auto;
  padding-block: 72px;
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(390px, 0.92fr);
  align-items: center;
  gap: 64px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  color: var(--bb-blue-800);
  font-size: 0.83rem;
  font-weight: 850;
  letter-spacing: 0.08em;
  line-height: 1.45;
  text-transform: uppercase;
}

.eyebrow::before {
  content: "";
  width: 34px;
  height: 3px;
  flex: 0 0 34px;
  background: var(--bb-yellow-strong);
  border-radius: 999px;
}

.hero .eyebrow {
  color: var(--bb-yellow);
}

.hero h1 {
  max-width: 900px;
  margin: 0.55rem 0 1.35rem;
  font-size: clamp(2.9rem, 5vw, 5.5rem);
  line-height: 1;
  letter-spacing: -0.045em;
}

.hero p {
  max-width: 790px;
  color: #e8f1ff;
  font-size: clamp(1.03rem, 1.45vw, 1.2rem);
  line-height: 1.75;
}

.hero-media {
  margin: 0;
  padding: 13px;
  color: var(--muted);
  background: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.24);
  border-radius: 26px;
  box-shadow: 0 28px 80px rgba(0, 0, 0, 0.3);
}

.hero-media img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  border-radius: 18px;
}

.hero-media figcaption {
  padding: 11px 5px 2px;
  font-size: 0.9rem;
}

.hero-actions {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 13px;
}

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  padding: 12px 19px;
  border: 1px solid transparent;
  border-radius: 12px;
  font-weight: 800;
  text-decoration: none;
  transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button.primary {
  color: var(--bb-blue-950);
  background: var(--bb-yellow);
  box-shadow: 0 9px 22px rgba(0, 0, 0, 0.18);
}

.button.primary:hover {
  background: #ffea45;
}

.button.secondary {
  color: #ffffff;
  border-color: rgba(255, 255, 255, 0.48);
  background: rgba(255, 255, 255, 0.07);
}

.button.secondary:hover {
  background: rgba(255, 255, 255, 0.14);
}

.overview {
  width: min(calc(100% - 72px), var(--max));
  margin: 0 auto;
  padding: 66px 44px;
  display: grid;
  grid-template-columns: minmax(270px, 0.72fr) minmax(0, 1.28fr);
  gap: 54px;
  background: #ffffff;
  border-inline: 1px solid var(--line);
}

.overview h2,
.faq-section h2 {
  margin: 0.5rem 0 1rem;
  color: var(--bb-blue-950);
  font-size: clamp(1.9rem, 3vw, 2.65rem);
  line-height: 1.16;
  letter-spacing: -0.025em;
}

.page-toc {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 11px;
}

.page-toc a {
  display: flex;
  min-height: 54px;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 15px;
  color: var(--bb-blue-800);
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: 12px;
  font-weight: 700;
  line-height: 1.35;
  text-decoration: none;
  transition: border-color 0.18s ease, background 0.18s ease, transform 0.18s ease;
}

.page-toc a:hover {
  background: var(--bb-blue-100);
  border-color: #b6c9e1;
  transform: translateY(-1px);
}

.content-layout {
  width: min(calc(100% - 72px), var(--max));
  margin-inline: auto;
  padding: 46px 0 90px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 330px;
  align-items: start;
  gap: 38px;
}

.article-content {
  min-width: 0;
}

.content-section {
  position: relative;
  margin-bottom: 25px;
  padding: clamp(30px, 4vw, 46px);
  overflow: hidden;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
}

.content-section::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 6px;
  background: linear-gradient(180deg, var(--bb-yellow), var(--bb-yellow-strong));
}

.content-section:nth-child(even)::before {
  background: linear-gradient(180deg, var(--bb-blue-700), var(--bb-blue-900));
}

.content-section h2 {
  max-width: var(--reading);
  margin: 0 0 20px;
  color: var(--bb-blue-950);
  font-size: clamp(1.7rem, 2.6vw, 2.45rem);
  line-height: 1.18;
  letter-spacing: -0.02em;
}

.content-section h3 {
  max-width: var(--reading);
  margin: 31px 0 12px;
  color: var(--bb-blue-800);
  font-size: 1.28rem;
  line-height: 1.34;
}

.content-section p {
  max-width: var(--reading);
  margin: 0 0 17px;
  color: #293d56;
  font-size: 1.03rem;
}

.content-section img {
  margin: 26px 0;
  border-radius: 18px;
  box-shadow: var(--shadow-soft);
}

.section-number {
  position: absolute;
  top: 20px;
  right: 28px;
  color: #dde6f1;
  font-size: 2.35rem;
  font-weight: 900;
  line-height: 1;
}

.related-panel {
  min-width: 0;
}

.sticky-box {
  position: sticky;
  top: 116px;
  padding: 28px;
  color: #ffffff;
  background: linear-gradient(160deg, var(--bb-blue-950), var(--bb-blue-800));
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 22px;
  box-shadow: var(--shadow);
}

.sticky-box .eyebrow {
  color: var(--bb-yellow);
}

.sticky-box h2 {
  margin: 0.55rem 0 1rem;
  color: #ffffff;
  line-height: 1.25;
}

.sticky-box a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 13px 0;
  color: #ffffff;
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
  text-decoration: none;
}

.sticky-box a:hover {
  color: var(--bb-yellow);
}

.notice {
  margin-top: 23px;
  color: #dbe8fa;
  font-size: 0.9rem;
}

.faq-section {
  padding: clamp(30px, 4vw, 42px);
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
}

.faq-section details {
  padding: 16px 0;
  border-top: 1px solid var(--line);
}

.faq-section summary {
  position: relative;
  padding-right: 42px;
  color: var(--bb-blue-900);
  font-weight: 800;
  cursor: pointer;
}

.faq-section summary::after {
  content: "+";
  position: absolute;
  top: -5px;
  right: 0;
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  color: var(--bb-blue-950);
  background: var(--bb-yellow);
  border-radius: 50%;
  font-size: 1.2rem;
}

.faq-section details[open] summary::after {
  content: "−";
}

.faq-section details p {
  margin-top: 13px;
  color: var(--muted);
}

.site-footer {
  position: relative;
  overflow: hidden;
  color: #dce8f7;
  background: linear-gradient(135deg, #031633, var(--bb-blue-950) 55%, #06295c);
}

.site-footer::after {
  content: "";
  position: absolute;
  right: -130px;
  bottom: -190px;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: rgba(255, 224, 0, 0.055);
  pointer-events: none;
}

.footer-inner {
  position: relative;
  z-index: 1;
  width: min(calc(100% - 72px), var(--max));
  margin-inline: auto;
  padding: 68px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr 0.9fr 1fr;
  gap: 50px;
}

.footer-brand-lockup {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 18px;
}

.footer-brand-lockup img {
  width: 62px;
  height: 62px;
  object-fit: cover;
  background: var(--bb-yellow);
  border-radius: 14px;
}

.footer-brand-lockup strong {
  display: block;
  color: #ffffff;
  font-size: 1.1rem;
  line-height: 1.25;
}

.footer-brand-lockup span {
  display: block;
  margin-top: 4px;
  color: var(--bb-yellow);
  font-size: 0.8rem;
}

.footer-brand p {
  max-width: 430px;
  color: #d6e3f4;
  font-size: 0.92rem;
  line-height: 1.65;
}

.footer-column h2 {
  position: relative;
  margin: 0 0 20px;
  padding-bottom: 13px;
  color: #ffffff;
  font-size: 0.97rem;
  line-height: 1.35;
}

.footer-column h2::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 42px;
  height: 3px;
  background: var(--bb-yellow);
  border-radius: 999px;
}

.footer-column nav {
  display: block;
}

.footer-column a {
  display: block;
  width: 100%;
  padding: 10px 0;
  color: #dce8f7;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 0.9rem;
  line-height: 1.4;
  text-decoration: none;
}

.footer-column a:hover {
  color: var(--bb-yellow);
}

.footer-column a[aria-current="page"] {
  color: var(--bb-yellow);
  font-weight: 800;
}

.footer-bottom {
  margin-top: 40px;
  padding-top: 25px;
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 32px;
  border-top: 1px solid rgba(255, 255, 255, 0.18);
}

.footer-bottom p {
  margin: 0;
  color: #d6e3f4;
  font-size: 0.85rem;
  line-height: 1.55;
}

.footer-bottom p + p {
  margin-top: 7px;
}

.footer-topics {
  flex: 0 0 auto;
  padding: 11px 16px;
  color: #ffffff !important;
  border: 1px solid var(--bb-yellow);
  border-radius: 12px;
  font-weight: 800;
  text-align: center;
}

.utility-main {
  width: min(calc(100% - 72px), 1120px);
  min-height: 56vh;
  margin-inline: auto;
  padding: 64px 0 90px;
}

.utility-hero {
  margin-bottom: 24px;
  padding: clamp(34px, 6vw, 62px);
  color: #ffffff;
  background: linear-gradient(130deg, var(--bb-blue-950), var(--bb-blue-800));
  border-radius: 25px;
  box-shadow: var(--shadow);
}

.utility-hero .eyebrow {
  color: var(--bb-yellow);
}

.utility-hero h1 {
  margin: 0.6rem 0 1rem;
  font-size: clamp(2.3rem, 5vw, 4.2rem);
  line-height: 1.05;
  letter-spacing: -0.035em;
}

.utility-hero p {
  max-width: 780px;
  color: #e8f1ff;
  font-size: 1.08rem;
}

.utility-content {
  padding: clamp(30px, 5vw, 52px);
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: 22px;
  box-shadow: var(--shadow-soft);
}

.utility-content h2 {
  margin: 0 0 1rem;
  color: var(--bb-blue-950);
  font-size: 1.75rem;
}

.utility-content h2:not(:first-child) {
  margin-top: 2.1rem;
}

.utility-content p,
.utility-content li {
  max-width: var(--reading);
  color: #293d56;
}

.utility-content a {
  color: var(--bb-blue-800);
  font-weight: 750;
}

.utility-grid,
.channel-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.utility-card,
.channel-card {
  padding: 24px;
  background: #f7faff;
  border: 1px solid #dce7f5;
  border-radius: 16px;
}

.utility-card h2,
.channel-card h2 {
  margin: 0 0 0.8rem;
  font-size: 1.3rem;
}

.utility-card p:last-child,
.channel-card p:last-child {
  margin-bottom: 0;
}

.utility-section + .utility-section,
.source-note,
.official-note {
  margin-top: 2.2rem;
}

.official-note,
.source-note {
  padding: 24px;
  border-radius: 16px;
}

.official-note {
  margin-top: 0;
  margin-bottom: 24px;
  background: #fff9d8;
  border: 1px solid #f0cf28;
}

.source-note {
  background: #eef5ff;
  border-left: 5px solid var(--bb-blue-800);
}

.official-note h2,
.source-note h2 {
  margin-top: 0;
  font-size: 1.35rem;
}

.channel-number {
  margin: 0.35rem 0 0.15rem;
  color: var(--bb-blue-950);
  font-size: 1.3rem;
  font-weight: 850;
}

.channel-number + p {
  margin-top: 0;
}

:focus-visible {
  outline: 3px solid var(--bb-yellow-strong);
  outline-offset: 3px;
}

@media (max-width: 1260px) {
  .brand {
    min-width: 270px;
  }

  .main-nav a {
    padding-inline: 8px;
    font-size: 0.8rem;
  }
}

@media (max-width: 1100px) {
  html {
    scroll-padding-top: 94px;
  }

  .header-inner {
    min-height: 82px;
    flex-wrap: wrap;
    padding-block: 11px;
  }

  .brand {
    min-width: 0;
    margin-right: auto;
  }

  .menu-toggle {
    display: inline-flex;
    align-items: center;
  }

  .main-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    max-height: calc(100vh - 82px);
    margin: 0;
    padding: 13px max(24px, calc((100% - var(--max)) / 2 + 24px)) 20px;
    display: none;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
    overflow: auto;
    background: #ffffff;
    border-top: 1px solid var(--line);
    box-shadow: 0 20px 45px rgba(4, 31, 73, 0.15);
  }

  .main-nav.open {
    display: grid;
  }

  .main-nav a {
    justify-content: flex-start;
    padding: 12px 14px;
    font-size: 0.92rem;
    text-align: left;
    background: var(--surface-soft);
  }

  .hero-inner {
    grid-template-columns: 1fr;
    min-height: auto;
    gap: 45px;
  }

  .hero-media {
    max-width: 760px;
  }

  .content-layout {
    grid-template-columns: 1fr;
  }

  .related-panel {
    order: -1;
  }

  .sticky-box {
    position: static;
  }

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

@media (max-width: 760px) {
  .portal-strip-inner {
    width: min(calc(100% - 30px), var(--max));
    min-height: 42px;
  }

  .portal-strip-secondary {
    display: none;
  }

  .header-inner,
  .hero-inner,
  .overview,
  .content-layout,
  .footer-inner,
  .utility-main {
    width: min(calc(100% - 30px), var(--max));
  }

  .header-inner {
    gap: 14px;
  }

  .brand img {
    width: 50px;
    height: 50px;
    flex-basis: 50px;
  }

  .brand strong {
    font-size: 0.96rem;
  }

  .brand small {
    font-size: 0.72rem;
  }

  .main-nav {
    grid-template-columns: 1fr;
    padding-inline: 15px;
  }

  .hero-inner {
    padding-block: 50px;
  }

  .hero h1 {
    font-size: clamp(2.55rem, 13vw, 4rem);
  }

  .overview {
    padding: 48px 24px;
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .page-toc {
    grid-template-columns: 1fr;
  }

  .content-layout {
    padding-top: 30px;
  }

  .content-section {
    padding: 29px 23px;
    border-radius: 18px;
  }

  .section-number {
    right: 20px;
    font-size: 1.8rem;
  }

  .footer-inner {
    padding-top: 54px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 36px;
  }

  .footer-bottom {
    align-items: stretch;
    flex-direction: column;
  }

  .footer-topics {
    width: 100%;
  }

  .utility-main {
    padding-block: 38px 65px;
  }

  .utility-grid,
  .channel-grid {
    grid-template-columns: 1fr;
  }

  .utility-hero,
  .utility-content {
    border-radius: 18px;
  }
}

@media (max-width: 430px) {
  .brand small {
    display: none;
  }

  .brand strong {
    max-width: 170px;
  }

  .menu-toggle {
    padding-inline: 12px;
    font-size: 0.9rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}