/* ==========================================================================
   Tectonic Finance Guide — base stylesheet
   Neutral, content-first design. No JS dependency for core layout.
   ========================================================================== */

:root {
  --ink: #1c2230;
  --ink-soft: #4a5266;
  --ink-faint: #6c7488;
  --line: #e4e7ee;
  --line-soft: #eef0f5;
  --paper: #ffffff;
  --paper-alt: #f7f8fb;
  --paper-tint: #f0f3f9;
  --accent: #2f5d8a;
  --accent-deep: #21456a;
  --accent-soft: #eaf1f8;
  --good: #2e7d62;
  --warn: #9a6a17;
  --radius: 10px;
  --radius-lg: 16px;
  --shadow: 0 1px 2px rgba(20, 30, 50, .05), 0 8px 24px rgba(20, 30, 50, .06);
  --maxw: 1080px;
  --font: "Iowan Old Style", "Palatino Linotype", "Source Serif Pro", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.65;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }
.narrow { max-width: 760px; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

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

/* ---------- Header / nav ---------- */
.site-head {
  position: sticky; top: 0; z-index: 40;
  background: rgba(255,255,255,.92);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; gap: 18px; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; color: var(--ink); font-size: 18px; letter-spacing: -.01em; }
.brand:hover { text-decoration: none; }
.brand .mark { width: 30px; height: 30px; flex: 0 0 auto; }
.brand small { display: block; font-weight: 500; font-size: 11px; color: var(--ink-faint); letter-spacing: .04em; text-transform: uppercase; }

.nav-links { display: flex; gap: 4px; margin-left: auto; align-items: center; flex-wrap: wrap; }
.nav-links a {
  color: var(--ink-soft); font-size: 15px; font-weight: 500;
  padding: 8px 12px; border-radius: 8px;
}
.nav-links a:hover { background: var(--paper-tint); color: var(--ink); text-decoration: none; }
.nav-links a[aria-current="page"] { color: var(--accent-deep); background: var(--accent-soft); }

.nav-toggle { display: none; }
.hamburger { display: none; }

/* ---------- Hero ---------- */
.hero { background: linear-gradient(180deg, var(--paper-alt), var(--paper)); border-bottom: 1px solid var(--line-soft); }
.hero-inner { padding: 64px 0 52px; display: grid; grid-template-columns: 1.3fr 1fr; gap: 40px; align-items: center; }
.hero h1 { margin: 0 0 14px; }
.eyebrow { display: inline-block; font-size: 13px; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--accent); background: var(--accent-soft); padding: 5px 11px; border-radius: 30px; margin-bottom: 16px; }
.hero p.lead { font-size: 19px; color: var(--ink-soft); margin: 0 0 24px; }
.hero-art { width: 100%; }

/* ---------- Typography ---------- */
h1, h2, h3, h4 { color: var(--ink); line-height: 1.22; letter-spacing: -.015em; font-weight: 700; }
h1 { font-size: 2.5rem; margin: .2em 0 .4em; }
h2 { font-size: 1.7rem; margin: 1.8em 0 .5em; }
h3 { font-size: 1.28rem; margin: 1.6em 0 .4em; }
h4 { font-size: 1.05rem; margin: 1.4em 0 .3em; color: var(--ink-soft); }
p { margin: 0 0 1.1em; }
.lead { font-size: 1.18rem; color: var(--ink-soft); }

main section { padding: 18px 0; }
.prose { font-size: 17px; }
.prose ul, .prose ol { padding-left: 1.3em; margin: 0 0 1.2em; }
.prose li { margin: .4em 0; }
.prose h2 { padding-top: .2em; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; font-family: var(--sans); font-weight: 600; font-size: 15px;
  padding: 11px 20px; border-radius: 9px; border: 1px solid transparent; cursor: pointer;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-deep); text-decoration: none; }
.btn-ghost { background: transparent; color: var(--accent); border-color: var(--line); }
.btn-ghost:hover { background: var(--paper-tint); text-decoration: none; }
.btn-row { display: flex; gap: 12px; flex-wrap: wrap; }

/* ---------- Cards / grids ---------- */
.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius-lg);
  padding: 24px; box-shadow: var(--shadow);
}
.card h3 { margin-top: 0; }
.card .ico { width: 38px; height: 38px; margin-bottom: 12px; }
.card-link { display: block; color: inherit; }
.card-link:hover { text-decoration: none; border-color: var(--accent); }
.card-link:hover h3 { color: var(--accent); }

.stat { text-align: center; }
.stat .num { font-size: 2rem; font-weight: 700; color: var(--accent-deep); letter-spacing: -.02em; }
.stat .cap { font-size: 14px; color: var(--ink-faint); }

/* ---------- Callouts ---------- */
.note, .callout {
  border: 1px solid var(--line); border-left: 4px solid var(--accent);
  background: var(--paper-alt); border-radius: 8px; padding: 16px 18px; margin: 1.4em 0;
}
.callout.warn { border-left-color: var(--warn); }
.callout.tip { border-left-color: var(--good); }
.callout p:last-child { margin-bottom: 0; }
.callout strong { color: var(--ink); }

/* ---------- Tables ---------- */
.table-wrap { overflow-x: auto; margin: 1.4em 0; }
table { border-collapse: collapse; width: 100%; font-size: 15px; }
th, td { text-align: left; padding: 11px 14px; border-bottom: 1px solid var(--line); }
th { background: var(--paper-alt); font-weight: 600; color: var(--ink-soft); }
tbody tr:hover { background: var(--paper-tint); }

/* ---------- Breadcrumbs ---------- */
.crumbs { font-size: 13px; color: var(--ink-faint); padding: 18px 0 0; }
.crumbs a { color: var(--ink-faint); }
.crumbs a:hover { color: var(--accent); }
.crumbs span { margin: 0 7px; opacity: .6; }

/* ---------- TOC / layout ---------- */
.with-aside { display: grid; grid-template-columns: 1fr 240px; gap: 48px; align-items: start; padding: 36px 0 60px; }
.toc { position: sticky; top: 84px; font-size: 14px; border-left: 2px solid var(--line); padding-left: 16px; }
.toc strong { display: block; text-transform: uppercase; letter-spacing: .05em; font-size: 12px; color: var(--ink-faint); margin-bottom: 10px; }
.toc a { display: block; color: var(--ink-soft); padding: 4px 0; }
.toc a:hover { color: var(--accent); text-decoration: none; }

/* ---------- Section banding ---------- */
.band { background: var(--paper-alt); border-top: 1px solid var(--line-soft); border-bottom: 1px solid var(--line-soft); }
.band-tint { background: var(--paper-tint); }

/* ---------- FAQ ---------- */
.faq details { border: 1px solid var(--line); border-radius: 10px; padding: 4px 18px; margin: 10px 0; background: var(--paper); }
.faq summary { cursor: pointer; font-weight: 600; padding: 12px 0; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; float: right; color: var(--accent); font-weight: 700; }
.faq details[open] summary::after { content: "–"; }
.faq details[open] summary { border-bottom: 1px solid var(--line-soft); }
.faq .answer { padding: 12px 0 6px; color: var(--ink-soft); }

/* ---------- Pills / tags ---------- */
.pills { display: flex; flex-wrap: wrap; gap: 8px; margin: 1em 0; }
.pill { font-size: 13px; padding: 5px 12px; border: 1px solid var(--line); border-radius: 30px; color: var(--ink-soft); background: var(--paper); }

/* ---------- Footer ---------- */
.site-foot { background: #161b26; color: #b9c0cf; margin-top: 60px; font-size: 15px; }
.foot-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 32px; padding: 52px 0 36px; }
.site-foot h4 { color: #fff; font-size: 14px; text-transform: uppercase; letter-spacing: .05em; margin: 0 0 14px; }
.site-foot a { color: #b9c0cf; }
.site-foot a:hover { color: #fff; }
.site-foot ul { list-style: none; padding: 0; margin: 0; }
.site-foot li { margin: 8px 0; }
.foot-brand p { color: #8b93a6; font-size: 14px; max-width: 34ch; }
.socials { display: flex; gap: 10px; margin-top: 14px; }
.socials a { width: 34px; height: 34px; border: 1px solid #2b3140; border-radius: 8px; display: flex; align-items: center; justify-content: center; }
.socials a:hover { border-color: #4a5266; background: #1d2330; }
.socials svg { width: 17px; height: 17px; fill: #b9c0cf; }
.foot-bottom { border-top: 1px solid #262c39; padding: 20px 0; display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; font-size: 13px; color: #7e8699; }
.disclaimer-bar { background: #11151d; color: #7e8699; font-size: 12.5px; padding: 14px 0; line-height: 1.55; }
.disclaimer-bar strong { color: #a7aebe; }

/* ---------- Misc ---------- */
.section-head { max-width: 640px; margin-bottom: 28px; }
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }
.muted { color: var(--ink-faint); }
.divider { height: 1px; background: var(--line); border: 0; margin: 40px 0; }
.kicker { font-size: 13px; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--accent); margin-bottom: 8px; }
.center { text-align: center; }
.mt0 { margin-top: 0; }
.related { display: grid; grid-template-columns: repeat(3,1fr); gap: 16px; margin: 24px 0; }
.related a { display: block; border: 1px solid var(--line); border-radius: 10px; padding: 16px; color: var(--ink); }
.related a:hover { border-color: var(--accent); text-decoration: none; }
.related .t { font-weight: 600; margin-bottom: 4px; }
.related .d { font-size: 14px; color: var(--ink-faint); }

.skip-link { position: absolute; left: -999px; top: 0; background: #fff; padding: 10px 16px; z-index: 100; }
.skip-link:focus { left: 8px; top: 8px; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; }
  .hero-art { max-width: 360px; }
  .with-aside { grid-template-columns: 1fr; }
  .toc { display: none; }
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .foot-grid { grid-template-columns: 1fr 1fr; }
  .related { grid-template-columns: 1fr; }
}
@media (max-width: 720px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.45rem; }
  .hamburger { display: flex; flex-direction: column; gap: 4px; margin-left: auto; background: none; border: 0; padding: 8px; cursor: pointer; }
  .hamburger span { width: 22px; height: 2px; background: var(--ink); display: block; }
  .nav-links {
    position: fixed; inset: 64px 0 auto 0; background: #fff; flex-direction: column;
    align-items: stretch; gap: 0; padding: 8px 16px 16px; border-bottom: 1px solid var(--line);
    margin-left: 0; display: none; box-shadow: var(--shadow);
  }
  .nav-toggle:checked ~ .nav-links { display: flex; }
  .nav-links a { padding: 12px 8px; border-bottom: 1px solid var(--line-soft); }
}
@media (max-width: 560px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .foot-grid { grid-template-columns: 1fr; }
  body { font-size: 16px; }
}