:root {
  --ink: #111827;
  --body: #3f4b5c;
  --muted: #59677a;
  --line: #d8dee7;
  --soft: #f7f5ef;
  --soft-blue: #f2f6fb;
  --gold: #865306;
  --gold-dark: #603a03;
  --navy: #173a63;
  --success: #176b36;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--body); background: #fff; font: 16px/1.7 "Segoe UI Variable Text", "Segoe UI", Roboto, Arial, sans-serif; -webkit-font-smoothing: antialiased; }
a { color: var(--gold-dark); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--navy); }
img { max-width: 100%; }
.content-container { width: min(calc(100% - 40px), 1080px); margin: 0 auto; }
.content-site-header { min-height: 68px; border-bottom: 1px solid var(--line); background: rgba(255,255,255,.98); }
.content-site-header .content-container { min-height: 68px; display: flex; align-items: center; gap: 28px; }
.content-brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; }
.content-brand img { width: 34px; height: 34px; }
.content-brand span { display: grid; line-height: 1.15; }
.content-brand strong { font-size: .94rem; }
.content-brand small { color: var(--muted); font-size: .67rem; }
.content-nav { margin-left: auto; display: flex; align-items: center; gap: 22px; }
.content-nav a { color: #425166; font-size: .84rem; font-weight: 650; text-decoration: none; }
.content-nav .content-nav-cta { padding: 9px 15px; border-radius: 9px; color: #fff; background: var(--gold); }
.content-menu { display: none; margin-left: auto; width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 9px; background: #fff; color: var(--ink); font-size: 1.25rem; }
.content-breadcrumbs { display: flex; flex-wrap: wrap; gap: 8px; padding-top: 24px; color: var(--muted); font-size: .78rem; }
.content-breadcrumbs a { color: var(--muted); }
.content-hero { padding: 48px 0 42px; border-bottom: 1px solid var(--line); background: linear-gradient(135deg, #fff 0%, #fcfaf5 58%, #f4f7fb 100%); }
.content-eyebrow { color: var(--gold); font-size: .74rem; font-weight: 800; letter-spacing: .1em; text-transform: uppercase; }
.content-hero h1 { max-width: 820px; margin: 12px 0 18px; color: var(--ink); font-size: clamp(2rem, 5vw, 3.2rem); line-height: 1.08; letter-spacing: -.035em; }
.content-hero p { max-width: 760px; margin: 0; color: #465468; font-size: 1.02rem; }
.content-meta { display: flex; flex-wrap: wrap; gap: 8px 20px; margin-top: 24px; color: var(--muted); font-size: .78rem; }
.content-layout { display: grid; grid-template-columns: minmax(0, 1fr) 280px; gap: 72px; align-items: start; padding: 56px 0 72px; }
.content-article { min-width: 0; }
.content-article h2 { margin: 44px 0 12px; color: var(--ink); font-size: 1.58rem; line-height: 1.2; letter-spacing: -.02em; }
.content-article h2:first-child { margin-top: 0; }
.content-article h3 { margin: 28px 0 8px; color: var(--ink); font-size: 1.08rem; }
.content-article p, .content-article li { color: var(--body); }
.content-article ul, .content-article ol { padding-left: 22px; }
.content-article li + li { margin-top: 8px; }
.content-rule, .content-example, .content-mistake, .content-practice { margin: 26px 0; padding: 22px 24px; border: 1px solid var(--line); border-radius: 14px; background: var(--soft-blue); }
.content-rule strong, .content-example strong, .content-mistake strong, .content-practice strong { display: block; margin-bottom: 6px; color: var(--ink); }
.content-rule { border-left: 4px solid var(--navy); }
.content-example { background: var(--soft); border-left: 4px solid var(--gold); }
.content-mistake { background: #fff9ed; border-left: 4px solid #a86506; }
.content-practice { background: #f1f8f3; border-left: 4px solid var(--success); }
.content-practice summary { cursor: pointer; color: var(--ink); font-weight: 750; }
.content-formula { display: block; margin: 10px 0; color: var(--ink); font: 700 1.03rem/1.6 ui-monospace, SFMono-Regular, Consolas, monospace; }
.content-toc { position: sticky; top: 24px; padding: 20px; border: 1px solid var(--line); border-radius: 14px; background: #fff; }
.content-toc strong { display: block; margin-bottom: 12px; color: var(--ink); font-size: .84rem; }
.content-toc a { display: block; padding: 7px 0; color: #465468; font-size: .8rem; text-decoration: none; }
.content-toc a + a { border-top: 1px solid #edf0f4; }
.content-cta { margin-top: 48px; padding: 28px; border-radius: 18px; background: #16273c; color: #fff; }
.content-cta h2 { margin: 0 0 10px; color: #fff; }
.content-cta p { color: #dce5f0; }
.content-button { display: inline-flex; min-height: 44px; align-items: center; justify-content: center; margin-top: 8px; padding: 10px 18px; border-radius: 9px; color: #fff; background: #9a620a; font-weight: 750; text-decoration: none; }
.content-button:hover { color: #fff; background: #b57816; }
.content-author { margin-top: 32px; padding-top: 20px; border-top: 1px solid var(--line); color: var(--muted); font-size: .8rem; }
.resource-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; margin-top: 28px; }
.resource-card { padding: 22px; border: 1px solid var(--line); border-radius: 14px; color: inherit; text-decoration: none; background: #fff; }
.resource-card:hover { border-color: #ae8a50; box-shadow: 0 10px 28px rgba(17,24,39,.06); }
.resource-card span { color: var(--gold); font-size: .7rem; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.resource-card h2 { margin: 7px 0; color: var(--ink); font-size: 1.12rem; }
.resource-card p { margin: 0; color: var(--muted); font-size: .85rem; }
.about-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin: 28px 0; }
.about-grid article { padding: 22px; border: 1px solid var(--line); border-radius: 14px; }
.about-grid strong { display: block; color: var(--ink); }
.content-site-footer { padding: 36px 0; border-top: 1px solid var(--line); background: #f8f9fb; }
.content-site-footer .content-container { display: flex; justify-content: space-between; gap: 24px; color: var(--muted); font-size: .75rem; }
.content-site-footer nav { display: flex; flex-wrap: wrap; gap: 16px; }
.content-site-footer a { color: var(--muted); }

@media (max-width: 780px) {
  .content-container { width: min(calc(100% - 28px), 1080px); }
  .content-menu { display: inline-grid; place-items: center; }
  .content-nav { display: none; position: absolute; z-index: 10; top: 62px; right: 14px; left: 14px; padding: 14px; border: 1px solid var(--line); border-radius: 12px; background: #fff; box-shadow: 0 16px 40px rgba(17,24,39,.12); }
  .content-nav.is-open { display: grid; }
  .content-nav a { padding: 8px 10px; }
  .content-hero { padding: 34px 0 32px; }
  .content-hero h1 { font-size: clamp(2rem, 10vw, 2.65rem); }
  .content-layout { grid-template-columns: 1fr; gap: 30px; padding: 38px 0 56px; }
  .content-toc { position: static; order: -1; }
  .resource-grid, .about-grid { grid-template-columns: 1fr; }
  .content-site-footer .content-container { flex-direction: column; }
}