.closed-circuit-guide {
  --cc-ink: #17221f;
  --cc-muted: #5c6965;
  --cc-line: #d8e0dc;
  --cc-paper: #f4f6f3;
  --cc-green: #176a49;
  --cc-deep: #10221c;
  color: var(--cc-ink);
  background: #fff;
}

.closed-circuit-guide main { overflow: clip; }
.closed-circuit-guide ::selection { color: #fff; background: var(--cc-green); }
.closed-circuit-guide a:focus-visible,
.closed-circuit-guide button:focus-visible { outline: 3px solid #d85522; outline-offset: 4px; }

.cc-wrap { width: min(1180px, calc(100% - 40px)); margin-inline: auto; }
.cc-hero { padding: 54px 0 58px; background: var(--cc-paper); border-bottom: 1px solid var(--cc-line); }
.cc-hero-grid { display: grid; grid-template-columns: minmax(0, 1.18fr) minmax(340px, .82fr); gap: clamp(36px, 5vw, 72px); align-items: center; }
.cc-breadcrumb { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; color: #63706c; font-size: 14px; font-weight: 700; }
.cc-breadcrumb a { text-decoration: underline; text-decoration-color: transparent; text-underline-offset: 4px; }
.cc-breadcrumb a:hover { text-decoration-color: currentColor; }
.cc-hero h1 { max-width: 790px; margin: 0; font-size: clamp(40px, 5vw, 66px); line-height: 1.03; letter-spacing: -.035em; text-wrap: balance; }
.cc-quick { max-width: 760px; margin-top: 26px; padding-top: 20px; border-top: 1px solid #cbd5d0; }
.cc-quick h2 { margin: 0 0 8px; color: var(--cc-green); font-size: 16px; line-height: 1.3; }
.cc-quick p { margin: 0; color: #43514d; font-size: 18px; line-height: 1.62; }
.cc-hero-media { margin: 0; overflow: hidden; background: #e5eae6; border-radius: 12px; box-shadow: 0 18px 42px rgba(16, 34, 28, .14); }
.cc-hero-media img { width: 100%; max-height: 330px; aspect-ratio: 4 / 3; object-fit: cover; }
.cc-hero-media figcaption,
.cc-flow-figure figcaption,
.cc-reference figcaption { padding: 11px 14px; color: #56635f; background: #fff; font-size: 13px; line-height: 1.5; }

.cc-section { padding: 66px 0; border-bottom: 1px solid var(--cc-line); }
.cc-heading { max-width: 810px; margin-bottom: 28px; }
.cc-heading h2,
.cc-copy-narrow h2,
.cc-circulating h2,
.cc-reference h2,
.cc-related h2 { margin: 0; font-size: clamp(30px, 3.5vw, 46px); line-height: 1.1; letter-spacing: -.025em; text-wrap: balance; }
.cc-heading p,
.cc-copy-narrow p,
.cc-circulating p,
.cc-reference p { color: var(--cc-muted); font-size: 17px; line-height: 1.7; }
.cc-heading p { margin: 12px 0 0; }

.cc-flow { background: #fff; }
.cc-flow-figure { max-width: 1080px; margin: 0; overflow: hidden; border: 1px solid var(--cc-line); border-radius: 12px; background: #fff; }
.cc-flow-figure img { display: block; width: 100%; height: auto; background: var(--cc-paper); }

.cc-two-column { display: grid; grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr); gap: clamp(42px, 7vw, 88px); align-items: start; }
.cc-two-column .cc-heading { margin: 0; }
.cc-definitions { margin: 0; border-top: 1px solid var(--cc-line); }
.cc-definitions > div { padding: 18px 0; border-bottom: 1px solid var(--cc-line); }
.cc-definitions dt,
.cc-factor-list dt { margin-bottom: 6px; font-size: 18px; font-weight: 800; }
.cc-definitions dd,
.cc-factor-list dd { margin: 0; color: var(--cc-muted); font-size: 16px; line-height: 1.62; }

.cc-return { background: var(--cc-paper); }
.cc-copy-narrow { max-width: 900px; }
.cc-copy-narrow p { max-width: 75ch; margin: 16px 0 0; }

.cc-factor-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); column-gap: 56px; margin: 0; border-top: 1px solid var(--cc-line); }
.cc-factor-list > div { padding: 20px 0; border-bottom: 1px solid var(--cc-line); }

.cc-circulating { color: #eef5f1; background: var(--cc-deep); border-bottom: 0; }
.cc-circulating-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(370px, .85fr); gap: clamp(42px, 6vw, 76px); align-items: center; }
.cc-circulating h2 { color: #fff; }
.cc-circulating p { color: #bdcbc5; }
.cc-load-equation { display: grid; grid-template-columns: 1fr auto 1.35fr auto 1fr; gap: 9px; align-items: center; }
.cc-load-equation span { padding: 16px 12px; border: 1px solid rgba(255,255,255,.24); text-align: center; font-size: 14px; font-weight: 800; line-height: 1.35; }
.cc-load-equation b { color: #e1bd6d; font-size: 22px; }

.cc-observation-list { border-top: 1px solid var(--cc-line); }
.cc-observation-list p { display: grid; grid-template-columns: minmax(210px, .42fr) minmax(0, 1fr); gap: 28px; margin: 0; padding: 18px 0; border-bottom: 1px solid var(--cc-line); }
.cc-observation-list strong { font-size: 17px; }
.cc-observation-list span { color: var(--cc-muted); font-size: 16px; line-height: 1.6; }

.cc-reference { background: var(--cc-paper); }
.cc-reference-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(380px, .9fr); gap: clamp(42px, 6vw, 72px); align-items: center; }
.cc-reference p { max-width: 65ch; margin: 16px 0 0; }
.cc-reference-link { display: inline-block; margin-top: 20px; color: var(--cc-green); font-weight: 800; text-decoration: underline; text-underline-offset: 5px; }
.cc-reference figure { margin: 0; overflow: hidden; border: 1px solid var(--cc-line); border-radius: 12px; background: #fff; }
.cc-reference figure img { display: block; width: 100%; aspect-ratio: 4 / 3; object-fit: contain; }

.cc-related { padding: 56px 0 64px; background: #fff; }
.cc-related-links { display: flex; flex-wrap: wrap; gap: 18px 28px; margin-top: 26px; }
.cc-related-links a { color: var(--cc-green); font-weight: 800; text-decoration: underline; text-underline-offset: 5px; }
.cc-related-links a:hover,
.cc-reference-link:hover { color: #0f5036; }
.cc-source-note { max-width: 90ch; margin: 26px 0 0; padding-top: 20px; color: #65716d; border-top: 1px solid var(--cc-line); font-size: 14px; line-height: 1.65; }
.cc-source-note a { color: #355f4f; text-decoration: underline; text-underline-offset: 3px; }

.closed-circuit-guide .mobile-menu-toggle { display: none; align-items: center; justify-content: center; min-height: 42px; padding: 0 14px; color: #1b2b34; background: #fff; border: 1px solid #c9d2d8; border-radius: 6px; font: inherit; font-weight: 700; cursor: pointer; }

@media (max-width: 900px) {
  .cc-hero-grid { grid-template-columns: minmax(0, 1.08fr) minmax(300px, .92fr); gap: 30px; }
  .cc-reference-grid { grid-template-columns: minmax(0, 1fr) minmax(320px, .82fr); gap: 34px; }
  .cc-circulating-grid { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .cc-wrap { width: min(100% - 32px, 1180px); }
  .cc-hero { padding: 30px 0 38px; }
  .cc-hero-grid,
  .cc-two-column,
  .cc-reference-grid { grid-template-columns: 1fr; gap: 24px; }
  .cc-breadcrumb { margin-bottom: 15px; font-size: 12px; }
  .cc-hero h1 { font-size: clamp(34px, 10vw, 43px); line-height: 1.04; }
  .cc-quick { margin-top: 19px; padding-top: 15px; }
  .cc-quick p { font-size: 16px; line-height: 1.58; }
  .cc-hero-media img { max-height: 235px; }
  .cc-section { padding: 44px 0; }
  .cc-heading { margin-bottom: 21px; }
  .cc-heading h2,
  .cc-copy-narrow h2,
  .cc-circulating h2,
  .cc-reference h2,
  .cc-related h2 { font-size: 30px; }
  .cc-heading p,
  .cc-copy-narrow p,
  .cc-circulating p,
  .cc-reference p { font-size: 16px; line-height: 1.62; }
  .cc-flow-figure img { width: 100%; }
  .cc-two-column .cc-heading { margin-bottom: 0; }
  .cc-definitions > div { padding: 16px 0; }
  .cc-definitions dt,
  .cc-factor-list dt { font-size: 17px; }
  .cc-definitions dd,
  .cc-factor-list dd { font-size: 15px; line-height: 1.58; }
  .cc-factor-list { grid-template-columns: 1fr; column-gap: 0; }
  .cc-factor-list > div { padding: 17px 0; }
  .cc-load-equation { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
  .cc-load-equation span { flex: 1 1 120px; padding: 13px 10px; }
  .cc-load-equation b { flex: 0 0 auto; font-size: 17px; }
  .cc-observation-list p { grid-template-columns: 1fr; gap: 7px; padding: 16px 0; }
  .cc-observation-list strong { font-size: 16px; }
  .cc-observation-list span { font-size: 15px; line-height: 1.58; }
  .cc-reference figure img { max-height: 250px; }
  .cc-related { padding: 42px 0 48px; }
  .cc-related-links { display: grid; gap: 17px; }
  .cc-related-links a { width: fit-content; }
  .cc-source-note { margin-top: 22px; }
  .closed-circuit-guide .site-header.nav-ready { grid-template-columns: minmax(0, 1fr) auto auto; padding-bottom: 8px; }
  .closed-circuit-guide .site-header.nav-ready .mobile-menu-toggle { display: inline-flex; grid-column: 3; grid-row: 1; }
}

@media (prefers-reduced-motion: reduce) {
  .closed-circuit-guide * { scroll-behavior: auto !important; transition: none !important; }
}