:root {
  --ink: #111a26;
  --muted: #58697e;
  --line: #cbd7e5;
  --paper: #ffffff;
  --canvas: #f5f8fc;
  --accent: #1f66c1;
  --soft: #eaf3ff;
  --shell: min(1180px, calc(100% - 48px));
  font-family: Arial, "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--paper);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; background: var(--paper); color: var(--ink); }
a { color: inherit; }
img { display: block; max-width: 100%; }
.shell { width: var(--shell); margin-inline: auto; }
.category-business { --accent: #146c5b; --soft: #e8f5f1; }
.category-career { --accent: #a14d21; --soft: #fff0e7; }
.category-official { --accent: #6c4aa1; --soft: #f2edfa; }
.category-content { --accent: #a83f56; --soft: #faedf0; }

.topic-header { position: sticky; top: 0; z-index: 20; background: rgba(255,255,255,.98); border-bottom: 1px solid var(--line); }
.topic-header .shell { min-height: 72px; display: flex; align-items: center; gap: 28px; }
.topic-brand { display: inline-flex; align-items: center; gap: 10px; margin-right: auto; text-decoration: none; }
.topic-brand img { width: 42px; height: 42px; object-fit: contain; }
.topic-brand span { display: grid; }
.topic-brand b { font-size: 16px; letter-spacing: -.02em; }
.topic-brand small { color: var(--muted); font-size: 11px; margin-top: 2px; }
.topic-header nav { display: flex; gap: 28px; }
.topic-header nav a { font-size: 14px; text-decoration: none; }
.topic-header nav a:hover { color: var(--accent); }
.header-cta, .button { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; padding: 0 20px; border: 1px solid var(--accent); background: var(--accent); color: #fff; font-weight: 700; text-decoration: none; transition: transform .18s ease, background .18s ease; }
.header-cta:hover, .button:hover { transform: translateY(-2px); background: color-mix(in srgb, var(--accent) 88%, #000); }
.breadcrumbs { min-height: 52px; display: flex; align-items: center; gap: 9px; color: #718095; font-size: 13px; }
.breadcrumbs a { text-decoration: none; }
.breadcrumbs a:hover { color: var(--accent); }

.topic-hero { overflow: hidden; border-block: 1px solid var(--line); background: linear-gradient(90deg,#fff 0 49%,var(--soft) 49% 100%); }
.topic-hero .shell { min-height: 0; display: grid; grid-template-columns: .88fr 1.12fr; align-items: center; gap: 20px; }
.hero-copy { padding-block: 70px; position: relative; z-index: 2; }
.eyebrow, .section-index { margin: 0 0 18px; color: var(--accent); font-size: 12px; line-height: 1.4; font-weight: 700; letter-spacing: .09em; text-transform: uppercase; }
.hero-copy h1 { max-width: 680px; margin: 0; font-size: clamp(44px, 5vw, 72px); line-height: .98; letter-spacing: -.055em; text-wrap: balance; }
.hero-answer { max-width: 620px; margin: 28px 0 0; color: #34465c; font-size: 19px; line-height: 1.65; text-wrap: pretty; }
.hero-actions { display: flex; align-items: center; gap: 24px; margin-top: 32px; }
.text-link { color: var(--accent); font-weight: 700; text-underline-offset: 5px; }
.hero-facts { display: flex; flex-wrap: wrap; gap: 0; margin: 34px 0 0; padding: 0; list-style: none; border-top: 1px solid var(--line); }
.hero-facts li { margin-top: 14px; padding-right: 18px; color: #647488; font-size: 13px; }
.hero-facts li + li { padding-left: 18px; border-left: 1px solid var(--line); }
.topic-visual { position: relative; margin: 0 -100px 0 0; padding: 30px; background: rgba(255,255,255,.35); border-left: 1px solid color-mix(in srgb,var(--accent) 30%,#fff); }
.topic-visual img { width: min(740px, 100%); height: auto; border: 1px solid #aec2da; box-shadow: 0 28px 60px rgba(38,74,116,.14); }
.topic-visual figcaption { max-width: 650px; margin-top: 12px; color: #647488; font-size: 12px; line-height: 1.5; }

.quick-answer { background: #101820; color: #fff; }
.quick-answer .shell { min-height: 0; display: grid; grid-template-columns: 250px 1fr; gap: 20px; align-items: center; }
.quick-answer .section-index { color: #91bdf4; }
.quick-answer h2 { max-width: 720px; margin: 0 0 18px; font-size: clamp(30px,4vw,48px); line-height: 1.04; letter-spacing: -.035em; }
.quick-answer p:last-child { max-width: 820px; margin: 0; color: #c7d2de; font-size: 17px; line-height: 1.7; }

.topic-context { padding: 28px 0; border-bottom: 1px solid var(--line); }
.topic-context .shell { display: grid; grid-template-columns: .74fr 1.26fr; gap: 90px; }
.context-heading h2 { max-width: 430px; margin: 0; font-size: clamp(32px,3.8vw,50px); line-height: 1.05; letter-spacing: -.04em; }
.context-copy > p { margin: 0 0 20px; color: var(--muted); font-size: 17px; line-height: 1.75; }
.context-copy dl { display: grid; grid-template-columns: repeat(3,1fr); margin: 38px 0 0; border-block: 1px solid var(--ink); }
.context-copy dl div { padding: 20px 20px 22px 0; }
.context-copy dl div + div { padding-left: 20px; border-left: 1px solid var(--line); }
.context-copy dt { margin-bottom: 9px; color: var(--accent); font-size: 12px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; }
.context-copy dd { margin: 0; font-size: 14px; line-height: 1.55; }

.topic-structure { padding: 28px 0; }
.topic-structure .shell { display: grid; grid-template-columns: .74fr 1.26fr; gap: 90px; }
.section-heading h2, .quality-check h2, .topic-cta h2 { margin: 0; font-size: clamp(34px,4vw,54px); line-height: 1.03; letter-spacing: -.04em; text-wrap: balance; }
.section-heading > p:last-child { max-width: 540px; margin: 22px 0 0; color: var(--muted); font-size: 17px; line-height: 1.7; }
.topic-structure ol { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.topic-structure li { display: grid; grid-template-columns: 58px 1fr; gap: 20px; padding: 28px 0; border-bottom: 1px solid var(--line); }
.topic-structure li > span { color: var(--accent); font-size: 13px; font-weight: 700; }
.topic-structure h3 { margin: 0 0 9px; font-size: 21px; }
.topic-structure li p { margin: 0; color: var(--muted); line-height: 1.65; }

.working-example { padding: 28px 0; background: var(--soft); border-block: 1px solid color-mix(in srgb,var(--accent) 28%,#fff); }
.working-example .shell { display: grid; grid-template-columns: 130px 1.25fr .75fr; gap: 54px; align-items: start; }
.example-label { display: grid; gap: 12px; color: var(--accent); }
.example-label span { font-size: 48px; line-height: 1; font-weight: 700; }
.example-label p { margin: 0; font-size: 12px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; }
.example-content h2 { margin: 0 0 26px; font-size: clamp(32px,3.8vw,50px); line-height: 1.05; letter-spacing: -.04em; }
.example-content > p { margin: 0; color: #32465a; font-size: 19px; line-height: 1.75; }
.example-content blockquote { margin: 38px 0 0; padding: 22px 0; border-block: 1px solid color-mix(in srgb,var(--accent) 45%,#fff); color: var(--accent); font-size: 17px; line-height: 1.6; font-weight: 700; }
.working-example aside { padding: 24px; background: #fff; border: 1px solid color-mix(in srgb,var(--accent) 35%,#fff); }
.working-example aside p:last-child { margin: 0; color: #394b5e; line-height: 1.65; }

.quality-check { padding: 28px 0; }
.quality-check .shell { display: grid; grid-template-columns: .82fr 1.18fr; gap: 90px; }
.quality-check ul { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--ink); }
.quality-check li { display: grid; grid-template-columns: 190px 1fr; gap: 28px; padding: 24px 0; border-bottom: 1px solid var(--line); }
.quality-check li b { font-size: 16px; }
.quality-check li span { color: var(--muted); line-height: 1.55; }

.topic-faq { padding: 28px 0; background: var(--canvas); border-block: 1px solid var(--line); }
.topic-faq .shell { display: grid; grid-template-columns: .8fr 1.2fr; gap: 90px; }
.faq-list { border-top: 1px solid var(--ink); }
.faq-list details { border-bottom: 1px solid var(--line); }
.faq-list summary { position: relative; padding: 24px 44px 24px 0; font-size: 17px; font-weight: 700; cursor: pointer; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: "+"; position: absolute; right: 4px; color: var(--accent); font-size: 24px; font-weight: 400; }
.faq-list details[open] summary::after { content: "×"; }
.faq-list p { margin: -6px 42px 24px 0; color: var(--muted); line-height: 1.7; }

.related-documents { padding: 28px 0; }
.related-documents .shell { display: grid; grid-template-columns: .58fr 1.42fr; gap: 80px; align-items: start; }
.related-documents h2 { margin: 0; font-size: 34px; letter-spacing: -.03em; }
.related-documents nav { display: grid; grid-template-columns: repeat(3,1fr); border-block: 1px solid var(--ink); }
.related-documents nav a { min-height: 132px; padding: 22px; border-right: 1px solid var(--line); text-decoration: none; font-size: 18px; font-weight: 700; transition: background .18s ease; }
.related-documents nav a:last-child { border-right: 0; }
.related-documents nav a:hover { background: var(--soft); }
.related-documents nav span { display: block; margin-bottom: 36px; color: var(--accent); font-size: 12px; }

.topic-cta { padding: 28px 0; background: #17212c; color: #fff; }
.topic-cta .shell { display: flex; align-items: flex-end; justify-content: space-between; gap: 60px; }
.topic-cta h2 { max-width: 760px; }
.topic-cta p:not(.eyebrow) { max-width: 680px; margin: 20px 0 0; color: #c8d3df; font-size: 17px; line-height: 1.65; }
.topic-cta .button { flex: none; background: #fff; border-color: #fff; color: #17212c; }
.topic-cta .button:hover { background: var(--soft); }
.topic-footer { background: #0c1117; color: #aeb9c5; }
.topic-footer .shell { min-height: 84px; display: flex; align-items: center; justify-content: space-between; gap: 28px; font-size: 13px; }
.topic-footer a { color: #fff; text-decoration: none; }

/* Six compositions rotate at page level; one brand system, different reading rhythm. */
.layout-1 .topic-hero { background: linear-gradient(90deg,var(--soft) 0 51%,#fff 51% 100%); }
.layout-1 .topic-hero .shell { grid-template-columns: 1.08fr .92fr; }
.layout-1 .topic-visual { order: -1; margin: 0; padding-left: 0; border: 0; }
.layout-1 .hero-copy { padding-left: 28px; }
.layout-2 .topic-hero { background: #fff; }
.layout-2 .topic-hero .shell { min-height: auto; padding-block: 66px 78px; grid-template-columns: 1fr; gap: 46px; }
.layout-2 .hero-copy { max-width: 930px; padding: 0; }
.layout-2 .topic-visual { margin: 0; padding: 24px; background: var(--soft); border: 1px solid var(--line); }
.layout-2 .topic-visual img { width: 100%; }
.layout-2 .quick-answer .shell { grid-template-columns: .65fr 1.35fr; }
.layout-3 .topic-hero .shell { grid-template-columns: .72fr 1.28fr; }
.layout-3 .topic-visual { transform: translateY(36px); }
.layout-3 .topic-structure .shell { grid-template-columns: 1fr; }
.layout-3 .topic-structure .section-heading { display: grid; grid-template-columns: .7fr 1.3fr; column-gap: 70px; }
.layout-3 .topic-structure ol { display: grid; grid-template-columns: repeat(2,1fr); }
.layout-3 .topic-structure li:nth-child(odd) { padding-right: 32px; border-right: 1px solid var(--line); }
.layout-3 .topic-structure li:nth-child(even) { padding-left: 32px; }
.layout-4 .topic-hero { background: var(--soft); }
.layout-4 .topic-hero .shell { grid-template-columns: 1fr 1fr; }
.layout-4 .hero-copy { background: #fff; margin-left: -60px; padding: 64px 60px; border: 1px solid var(--line); }
.layout-4 .topic-visual { margin: 0; padding: 0; border: 0; }
.layout-4 .working-example .shell { grid-template-columns: .7fr 1.3fr; }
.layout-4 .working-example aside { grid-column: 1; grid-row: 1 / span 2; margin-top: 92px; }
.layout-4 .example-label { grid-column: 2; grid-row: 1; display: flex; align-items: baseline; }
.layout-4 .example-content { grid-column: 2; }
.layout-5 .topic-hero { background: linear-gradient(180deg,#fff 0 72%,var(--soft) 72% 100%); }
.layout-5 .topic-hero .shell { min-height: 0; grid-template-columns: 1fr 1fr; gap: 20px; }
.layout-5 .topic-visual { margin-right: -54px; transform: rotate(1deg); }
.layout-5 .quality-check .shell { grid-template-columns: 1fr; }
.layout-5 .quality-check ul { display: grid; grid-template-columns: repeat(2,1fr); }
.layout-5 .quality-check li:nth-child(odd) { padding-right: 28px; border-right: 1px solid var(--line); }
.layout-5 .quality-check li:nth-child(even) { padding-left: 28px; }

@media (prefers-reduced-motion: no-preference) {
  .topic-visual img { animation: visual-arrive .7s cubic-bezier(.2,.7,.2,1) both; }
  .hero-copy > * { animation: copy-arrive .6s cubic-bezier(.2,.7,.2,1) both; }
  .hero-copy > :nth-child(2) { animation-delay: .06s; }
  .hero-copy > :nth-child(3) { animation-delay: .12s; }
  .hero-copy > :nth-child(4) { animation-delay: .18s; }
  @keyframes visual-arrive { from { opacity: 0; transform: translateY(18px); } }
  @keyframes copy-arrive { from { opacity: 0; transform: translateY(12px); } }
}

@media (max-width: 980px) {
  :root { --shell: min(100% - 36px, 760px); }
  .topic-header nav { display: none; }
  .topic-hero, .layout-1 .topic-hero, .layout-2 .topic-hero, .layout-4 .topic-hero, .layout-5 .topic-hero { background: linear-gradient(180deg,#fff 0 50%,var(--soft) 50% 100%); }
  .topic-hero .shell, .layout-1 .topic-hero .shell, .layout-4 .topic-hero .shell, .layout-5 .topic-hero .shell { min-height: auto; grid-template-columns: 1fr; gap: 34px; padding-block: 54px; }
  .layout-1 .topic-visual { order: 0; }
  .layout-1 .hero-copy, .layout-4 .hero-copy { margin: 0; padding: 0; background: transparent; border: 0; }
  .topic-visual, .layout-3 .topic-visual, .layout-5 .topic-visual { margin: 0; padding: 18px; transform: none; }
  .quick-answer .shell, .layout-2 .quick-answer .shell, .topic-context .shell, .topic-structure .shell, .quality-check .shell, .topic-faq .shell, .related-documents .shell { grid-template-columns: 1fr; gap: 38px; padding-block: 70px; }
  .working-example .shell, .layout-4 .working-example .shell { grid-template-columns: 90px 1fr; }
  .working-example aside, .layout-4 .working-example aside { grid-column: 2; grid-row: auto; margin: 0; }
  .layout-4 .example-label, .layout-4 .example-content { grid-column: auto; grid-row: auto; }
  .layout-3 .topic-structure .section-heading { display: block; }
  .related-documents nav { grid-template-columns: 1fr; }
  .related-documents nav a { min-height: auto; border-right: 0; border-bottom: 1px solid var(--line); }
  .related-documents nav a:last-child { border-bottom: 0; }
  .related-documents nav span { margin-bottom: 12px; }
}

@media (max-width: 640px) {
  :root { --shell: calc(100% - 32px); }
  .topic-header .shell { min-height: 64px; }
  .topic-brand small, .header-cta { display: none; }
  .topic-brand b { font-size: 14px; }
  .breadcrumbs { overflow: hidden; white-space: nowrap; }
  .breadcrumbs a:first-child, .breadcrumbs span:first-of-type { display: none; }
  .topic-hero .shell, .layout-2 .topic-hero .shell { padding-block: 40px; }
  .hero-copy { padding: 0; }
  .hero-copy h1 { font-size: clamp(38px, 12vw, 54px); }
  .hero-answer { font-size: 17px; line-height: 1.55; }
  .hero-actions { align-items: stretch; flex-direction: column; gap: 16px; }
  .button { width: 100%; }
  .text-link { text-align: center; }
  .hero-facts { display: grid; grid-template-columns: 1fr; }
  .hero-facts li + li { padding-left: 0; border-left: 0; }
  .topic-visual { padding: 10px; }
  .topic-visual figcaption { display: none; }
  .quick-answer .shell { min-height: 0; padding-block: 58px; }
  .topic-structure, .quality-check, .topic-faq, .working-example { padding-block: 72px; }
  .topic-context { padding-block: 72px; }
  .context-copy dl { grid-template-columns: 1fr; }
  .context-copy dl div { padding: 18px 0; }
  .context-copy dl div + div { padding-left: 0; border-left: 0; border-top: 1px solid var(--line); }
  .section-heading h2, .quality-check h2, .topic-cta h2 { font-size: 36px; }
  .topic-structure li { grid-template-columns: 42px 1fr; }
  .layout-3 .topic-structure ol { grid-template-columns: 1fr; }
  .layout-3 .topic-structure li:nth-child(n) { padding-inline: 0; border-right: 0; }
  .working-example .shell, .layout-4 .working-example .shell { grid-template-columns: 1fr; gap: 28px; }
  .working-example aside, .layout-4 .working-example aside { grid-column: 1; }
  .example-label { display: flex; align-items: baseline; gap: 14px; }
  .quality-check li { grid-template-columns: 1fr; gap: 8px; }
  .layout-5 .quality-check ul { grid-template-columns: 1fr; }
  .layout-5 .quality-check li:nth-child(n) { padding-inline: 0; border-right: 0; }
  .topic-cta { padding-block: 72px; }
  .topic-cta .shell { align-items: stretch; flex-direction: column; }
  .topic-footer .shell { min-height: 112px; align-items: flex-start; justify-content: center; flex-direction: column; gap: 8px; }
}