/* ============================================================
   Layout — reset + sidebar TOC + content column + hero
   ============================================================ */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;   /* sticky nav offset */
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-serif);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--band-c-fg);
  background: var(--band-c-bg);
  -webkit-font-smoothing: antialiased;
}

img, svg { max-width: 100%; display: block; }
a { color: var(--band-b-accent); text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { color: var(--band-b-accent-strong); text-decoration-thickness: 2px; }

/* ── Top bar (Band A) ─────────────────────────────────────── */

.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--band-a-bg);
  color: var(--band-a-fg);
  border-bottom: 1px solid var(--band-a-rule);
  font-family: var(--font-sans);
}
.topbar-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 1.5rem;
}
.topbar-brand {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--band-a-fg);
  text-decoration: none;
  letter-spacing: 0.5px;
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
}
.topbar-brand:hover { color: var(--band-a-fg); text-decoration: none; }
.topbar-brand .mark {
  display: inline-block;
  padding: 0.15rem 0.5rem;
  background: var(--band-b-accent);
  color: white;
  border-radius: 2px;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  vertical-align: middle;
}
.topbar-nav {
  margin-left: auto;
  display: flex;
  gap: 1.25rem;
  font-size: 0.9rem;
}
.topbar-nav a {
  color: var(--band-a-fg-dim);
  text-decoration: none;
}
.topbar-nav a:hover { color: var(--band-a-fg); }

/* ── Hero (Band A) ────────────────────────────────────────── */

.hero {
  background: linear-gradient(135deg, var(--band-a-bg) 0%, var(--band-a-bg-2) 100%);
  color: var(--band-a-fg);
  padding: 4rem 1.25rem 3rem;
  border-bottom: 4px solid var(--band-b-accent);
}
.hero-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding-left: calc(var(--sidebar-w) + 3rem);
}
@media (max-width: 1100px) {
  .hero-inner { padding-left: 1.25rem; }
}
.hero h1 {
  font-family: var(--font-serif);
  font-size: var(--fs-hero);
  line-height: 1.1;
  margin: 0 0 1rem 0;
  letter-spacing: -0.5px;
}
.hero .eyebrow {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--band-a-fg-dim);
  margin-bottom: 1rem;
}
.hero .lede {
  font-size: 1.25rem;
  line-height: 1.5;
  max-width: 720px;
  color: var(--band-a-fg);
  opacity: 0.9;
}
.hero .hero-stats {
  display: flex;
  gap: 2.5rem;
  margin-top: 2.5rem;
  flex-wrap: wrap;
}
.hero .hero-stat {
  font-family: var(--font-sans);
}
.hero .hero-stat .num {
  font-size: 2.3rem;
  font-weight: 700;
  color: white;
  line-height: 1;
  display: block;
}
.hero .hero-stat .label {
  font-size: 0.75rem;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--band-a-fg-dim);
  margin-top: 0.4rem;
  display: block;
}

/* ── Main layout: sidebar + content ───────────────────────── */

.page {
  max-width: 1280px;
  margin: 0 auto;
  padding: 2rem 1.25rem 4rem;
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  gap: 3rem;
  align-items: start;
}
@media (max-width: 1100px) {
  .page { grid-template-columns: 1fr; gap: 1.5rem; }
}

/* ── Sidebar TOC ──────────────────────────────────────────── */

.toc {
  position: sticky;
  top: 80px;
  max-height: calc(100vh - 100px);
  overflow-y: auto;
  font-family: var(--font-sans);
  font-size: 0.87rem;
  padding-right: 0.5rem;
}
@media (max-width: 1100px) {
  .toc {
    position: static;
    max-height: none;
    padding: 1rem 1.25rem;
    background: var(--band-c-bg-alt);
    border: 1px solid var(--band-c-rule);
    border-radius: var(--page-radius);
  }
}
.toc h2 {
  font-family: var(--font-sans);
  font-size: 0.72rem;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--band-c-fg-dim);
  margin: 0 0 0.8rem 0;
  font-weight: 600;
}
.toc ol {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: toc;
}
.toc ol > li {
  counter-increment: toc;
  margin: 0.35rem 0;
  line-height: 1.35;
}
.toc ol > li::before {
  content: counter(toc, decimal-leading-zero);
  color: var(--band-c-fg-dim);
  font-size: 0.75rem;
  font-variant-numeric: tabular-nums;
  margin-right: 0.6rem;
}
.toc a {
  color: var(--band-c-fg);
  text-decoration: none;
  display: inline;
}
.toc a:hover { color: var(--band-b-accent); text-decoration: underline; }
.toc .sub {
  list-style: none;
  padding: 0 0 0 1.5rem;
  margin: 0.3rem 0 0.5rem 0;
  font-size: 0.83rem;
  color: var(--band-c-fg-dim);
}
.toc .sub li { margin: 0.2rem 0; }

/* ── Content column ───────────────────────────────────────── */

.content {
  min-width: 0;
}
.content section {
  margin-bottom: 3.5rem;
  scroll-margin-top: 80px;
}
.content h2 {
  font-family: var(--font-serif);
  font-size: var(--fs-h1);
  line-height: 1.2;
  margin: 0 0 1rem 0;
  padding-bottom: 0.5rem;
  border-bottom: 3px solid var(--band-a-bg);
  letter-spacing: -0.3px;
}
.content h3 {
  font-family: var(--font-serif);
  font-size: var(--fs-h3);
  margin: 2rem 0 0.5rem 0;
  color: var(--band-a-bg);
}
.content p { margin: 0 0 1rem 0; }
.content ul, .content ol { margin: 0 0 1rem 1.5rem; padding: 0; }
.content li { margin: 0.35rem 0; }

/* ── Footer (Band A) ──────────────────────────────────────── */

.footer {
  background: var(--band-a-bg);
  color: var(--band-a-fg-dim);
  padding: 3rem 1.25rem;
  font-family: var(--font-sans);
  font-size: 0.85rem;
  border-top: 4px solid var(--band-b-accent);
}
.footer-inner {
  max-width: 1280px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 3rem;
}
@media (max-width: 800px) {
  .footer-inner { grid-template-columns: 1fr; gap: 1.5rem; }
}
.footer h4 {
  font-family: var(--font-sans);
  font-size: 0.72rem;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--band-a-fg);
  margin: 0 0 0.8rem 0;
}
.footer a { color: var(--band-a-fg); text-decoration: none; }
.footer a:hover { text-decoration: underline; }
.footer p { margin: 0 0 0.5rem 0; }