/* Financial AI essays — distinct from AI Orchestration blog chrome.
   Textbook-precursor: cream page, ink type, amber rail, clean formula panels. */
:root {
  --page: #f6f1e8;
  --ink: #14110f;
  --muted: #5c534a;
  --faint: #8a7f72;
  --line: #ddd2c4;
  --card: #fffdf8;
  --rail: #c45c26;
  --rail-soft: #f3e0d4;
  --ink-blue: #1e3a5f;
  --ok: #1f6b4a;
  --bad: #9b2c2c;
  --serif: "Source Serif Pro", "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  --sans: "Lato", "Noto Sans", ui-sans-serif, system-ui, sans-serif;
  --mono: "JetBrains Mono", "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  --max: 880px; /* match earlier book essay measure */
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background:
    linear-gradient(90deg, var(--rail-soft) 0 0.55rem, transparent 0.55rem),
    var(--page);
  color: var(--ink);
  font-family: var(--serif);
  /* same scale as AI Orchestration essays — do not enlarge page body */
  font-size: 1rem;
  line-height: 1.55;
}
a { color: var(--ink-blue); text-decoration-thickness: 1px; text-underline-offset: 0.12em; }
a:hover { color: var(--rail); }
.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 2rem 1.25rem 4rem;
}
.nav {
  display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap;
  font-family: var(--sans); font-size: 0.85rem; color: var(--muted);
  margin: 0 0 1.5rem;
}
.nav a { color: var(--muted); text-decoration: none; font-weight: 600; }
.nav a:hover { color: var(--rail); }
.hero {
  padding: 0.5rem 0 1.75rem;
  border-bottom: 2px solid var(--ink);
  margin-bottom: 1.75rem;
}
.kicker {
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--rail);
  margin: 0 0 0.75rem;
}
h1 {
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  line-height: 1.15;
  margin: 0 0 0.75rem;
  font-weight: 600;
}
.lead {
  font-size: 1.05rem;
  color: var(--muted);
  margin: 0 0 1rem;
  max-width: 42rem;
  line-height: 1.55;
}
.howto {
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 4px solid var(--rail);
  border-radius: 2px 10px 10px 2px;
  padding: 1rem 1.15rem;
  margin: 0 0 1.75rem;
  font-family: var(--sans);
  font-size: 0.95rem;
  color: var(--muted);
}
.howto strong {
  display: block;
  color: var(--ink);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.4rem;
}
.figure {
  margin: 1.75rem 0 2rem;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
}
.figure-cap {
  font-family: var(--sans);
  font-size: 0.88rem;
  color: var(--muted);
  padding: 0.85rem 1.1rem 0.35rem;
  line-height: 1.45;
}
.figure-cap strong { color: var(--ink); }
.figure img {
  display: block;
  width: 100%;
  height: auto;
  background: #fff;
  border-top: 1px solid var(--line);
}
article h2 {
  font-family: var(--sans);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  margin: 2.35rem 0 0.85rem;
  padding-top: 0.35rem;
  color: var(--ink);
  border-top: 1px solid var(--line);
}
article h2:first-of-type { border-top: 0; padding-top: 0; }
article h3 {
  font-family: var(--sans);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--ink-blue);
  margin: 1.5rem 0 0.55rem;
}
article p { margin: 0 0 1rem; }
article ul, article ol { margin: 0 0 1.1rem; padding-left: 1.25rem; }
article li { margin-bottom: 0.45rem; }
article blockquote {
  margin: 1.1rem 0;
  padding: 0.85rem 1.1rem;
  border-left: 3px solid var(--rail);
  background: var(--rail-soft);
  color: var(--ink);
  font-style: italic;
}
table.data {
  width: 100%;
  border-collapse: collapse;
  margin: 1.1rem 0 1.35rem;
  font-size: 0.95rem;
  background: var(--card);
}
table.data th, table.data td {
  border: 1px solid var(--line);
  padding: 0.55rem 0.7rem;
  text-align: left;
  vertical-align: top;
}
table.data th {
  font-family: var(--sans);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  background: #f0ebe3;
}
.formula {
  font-family: var(--mono);
  font-size: 0.92rem;
  line-height: 1.55;
  background: #1a2332;
  color: #e8eef7;
  padding: 1rem 1.15rem;
  border-radius: 10px;
  margin: 1rem 0 1.25rem;
  overflow-x: auto;
}
.formula .lbl {
  display: block;
  font-family: var(--sans);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #9db0c9;
  margin-bottom: 0.45rem;
}
.callout {
  margin: 1.25rem 0;
  padding: 1rem 1.15rem;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: var(--card);
}
.callout .t {
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.4rem;
}
.callout.lock { border-color: #b7d7c8; background: #f2faf6; }
.callout.lock .t { color: var(--ok); }
.callout.warn { border-color: #e5b4b4; background: #fdf4f4; }
.callout.warn .t { color: var(--bad); }
.callout.idea { border-color: #c9d6e8; background: #f4f7fb; }
.callout.idea .t { color: var(--ink-blue); }
.side {
  margin-top: 2.25rem;
  padding: 1rem 1.15rem;
  background: #1a2332;
  color: #c9d4e3;
  border-radius: 10px;
  font-family: var(--sans);
  font-size: 0.9rem;
  line-height: 1.5;
}
.side strong { display: block; color: #fff; margin-bottom: 0.4rem; font-size: 0.78rem; letter-spacing: 0.06em; text-transform: uppercase; }
.side em { color: #fff; font-style: normal; font-weight: 600; }
footer.ep-foot {
  margin-top: 3rem;
  padding-top: 1.1rem;
  border-top: 2px solid var(--ink);
  font-family: var(--sans);
  font-size: 0.85rem;
  color: var(--muted);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}
@media (max-width: 640px) {
  body { background: var(--page); }
  .wrap { padding: 1.35rem 1rem 3.5rem; }
}