:root {
  --bg: #f4ead7;
  --paper: #fffaf0;
  --ink: #3a2d1f;
  --ink-soft: #6b5946;
  --line: #e0d0b2;
  --green: #4c7a34;
  --green-dark: #35561f;
  --gold: #c98a1c;
  --blue: #2f6d8f;
  --on-accent: #fff8e6;
  --banner-from: #35561f;
  --banner-to: #4c7a34;
  --banner-ink: #fff8e6;
  --shadow: 0 1px 0 #e7dbc2, 0 6px 20px rgba(58, 45, 31, .07);
  --sidebar: 300px;
  --header-offset: 76px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
  --bg: #1c1913;
  --paper: #25211a;
  --ink: #ece3d3;
  --ink-soft: #a99c85;
  --line: #3b352a;
  --green: #7fae52;
  --green-dark: #a8d47c;
  --gold: #e0ab4b;
  --blue: #79b6d4;
  --on-accent: #16200f;
  --banner-from: #1f2f18;
  --banner-to: #2d4522;
  --banner-ink: #e8f2da;
  --shadow: 0 6px 20px rgba(0, 0, 0, .3);
  color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --bg: #1c1913;
  --paper: #25211a;
  --ink: #ece3d3;
  --ink-soft: #a99c85;
  --line: #3b352a;
  --green: #7fae52;
  --green-dark: #a8d47c;
  --gold: #e0ab4b;
  --blue: #79b6d4;
  --on-accent: #16200f;
  --banner-from: #1f2f18;
  --banner-to: #2d4522;
  --banner-ink: #e8f2da;
  --shadow: 0 6px 20px rgba(0, 0, 0, .3);
  color-scheme: dark;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: var(--header-offset); }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.65 "Inter" "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  -webkit-text-size-adjust: 100%;
}

a { color: var(--blue); }

/* ---------- progress bar ---------- */
#progress {
  position: fixed; inset: 0 0 auto 0; height: 3px; z-index: 60;
  background: transparent; pointer-events: none;
}
#progress span {
  display: block; height: 100%; width: 0;
  background: linear-gradient(90deg, var(--green), var(--gold));
}

/* ---------- banner ---------- */
.banner {
  background:
    radial-gradient(120% 140% at 12% 0%, rgba(255, 255, 255, .22), transparent 60%),
    linear-gradient(160deg, var(--banner-from), var(--banner-to));
  color: var(--banner-ink);
  padding: 56px 24px 44px;
  border-bottom: 4px solid rgba(0, 0, 0, .18);
}
.banner-inner { max-width: 1180px; margin: 0 auto; }
.eyebrow {
  margin: 0 0 6px; text-transform: uppercase; letter-spacing: .22em;
  font-size: 12px; font-weight: 700; opacity: .8;
  font-family: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}
.banner h1 {
  margin: 0; font-size: clamp(28px, 4.4vw, 46px); line-height: 1.12;
  letter-spacing: -.01em; text-shadow: 0 2px 0 rgba(0, 0, 0, .18);
}
.tagline { margin: 14px 0 0; max-width: 62ch; font-size: 17px; opacity: .92; }
.source { margin: 18px 0 0; font-size: 13px; opacity: .82; }
.source a { color: inherit; }

/* ---------- layout ---------- */
.layout {
  max-width: 1180px; margin: 0 auto; padding: 0 24px 80px;
  display: grid; grid-template-columns: var(--sidebar) minmax(0, 1fr); gap: 44px;
  align-items: start;
}

/* ---------- sticky table of contents ---------- */
#toc {
  position: sticky; top: 0;
  max-height: 100vh; overflow-y: auto; overscroll-behavior: contain;
  padding: 28px 6px 40px 0;
  scrollbar-width: thin;
}
.toc-head {
  margin: 0 0 12px; font-size: 11px; letter-spacing: .2em; text-transform: uppercase;
  color: var(--ink-soft); font-family: ui-monospace, Menlo, Consolas, monospace;
}
#toc ul { list-style: none; margin: 0; padding: 0; }
#toc a {
  display: flex; gap: 8px; align-items: baseline;
  padding: 5px 10px; border-radius: 6px;
  color: var(--ink-soft); text-decoration: none;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  font-size: 13.5px; line-height: 1.4;
  border-left: 2px solid transparent;
}
#toc a:hover { background: rgba(76, 122, 52, .1); color: var(--ink); }
.toc-part-link { font-weight: 650; font-size: 14px !important; color: var(--ink) !important; margin-top: 10px; }
.toc-roman, .toc-num {
  flex: none; font-variant-numeric: tabular-nums; font-size: 11px;
  color: var(--gold); font-weight: 700; min-width: 26px;
  font-family: ui-monospace, Menlo, Consolas, monospace;
}
.toc-part > ul { margin: 2px 0 4px 13px; border-left: 1px solid var(--line); }
#toc a.active {
  background: rgba(76, 122, 52, .16); color: var(--green-dark);
  border-left-color: var(--green); font-weight: 650;
}
#toc a.active .toc-num, #toc a.active .toc-roman { color: var(--green-dark); }
.toc-part.in-view > .toc-part-link { color: var(--green-dark) !important; }

/* ---------- content ---------- */
main { min-width: 0; padding-top: 28px; }

.part { margin: 0 0 12px; }
.part h2 {
  display: flex; align-items: baseline; gap: 14px;
  margin: 52px 0 20px; padding-bottom: 12px;
  font-size: clamp(24px, 3vw, 32px); line-height: 1.2; letter-spacing: -.01em;
  border-bottom: 3px solid var(--line);
}
.part:first-child h2 { margin-top: 8px; }
.part-roman {
  flex: none; font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 14px; font-weight: 700; color: var(--on-accent);
  background: var(--green); padding: 5px 10px; border-radius: 6px;
  letter-spacing: .04em;
}

.sub {
  background: var(--paper); border: 1px solid var(--line); border-radius: 12px;
  padding: 22px 26px; margin: 0 0 20px; box-shadow: var(--shadow);
}
.sub h3 {
  display: flex; align-items: baseline; gap: 10px;
  margin: 0 0 14px; font-size: 20px; line-height: 1.3; color: var(--green-dark);
}
.sub-num {
  flex: none; font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 13px; color: var(--gold);
}
.sub h4 {
  margin: 22px 0 8px; font-size: 15px; letter-spacing: .02em;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--ink);
}
.sub h4::before { content: "▸ "; color: var(--gold); }
.sub > :first-child, .intro > :first-child { margin-top: 0; }
.sub > :last-child, .intro > :last-child { margin-bottom: 0; }

.intro { margin: 0 0 20px; font-size: 16.5px; }
.intro.card {
  background: var(--paper); border: 1px solid var(--line); border-radius: 12px;
  padding: 22px 26px; box-shadow: var(--shadow); font-size: 16px;
}
.intro .points { padding-left: 20px; }

.lead {
  margin: 18px 0 6px; font-weight: 700;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif; font-size: 14.5px;
}

ul.points { margin: 8px 0 14px; padding-left: 22px; }
ul.points li { margin: 5px 0; }
ul.points li::marker { color: var(--green); }
strong { color: var(--green-dark); }

/* ---------- callouts ---------- */
.callout {
  display: flex; gap: 10px; margin: 14px 0;
  padding: 12px 15px; border-radius: 9px; font-size: 15px;
  background: rgba(201, 138, 28, .1); border-left: 3px solid var(--gold);
}
.callout.pick { background: rgba(76, 122, 52, .12); border-left-color: var(--green); }
.callout.note { background: rgba(47, 109, 143, .1); border-left-color: var(--blue); }
.callout-mark { flex: none; }

/* ---------- tables ---------- */
.table-wrap { overflow-x: auto; margin: 12px 0 18px; border: 1px solid var(--line); border-radius: 9px; }
table { border-collapse: collapse; width: 100%; font-size: 14.5px; }
thead th {
  background: rgba(76, 122, 52, .14); text-align: left; font-weight: 700;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif; font-size: 13px;
  letter-spacing: .03em; color: var(--green-dark);
  padding: 10px 14px; white-space: nowrap;
}
td { padding: 9px 14px; border-top: 1px solid var(--line); vertical-align: top; }
tbody tr:nth-child(even) { background: rgba(0, 0, 0, .025); }
tbody tr:hover { background: rgba(76, 122, 52, .07); }
td:first-child { font-weight: 650; white-space: nowrap; }

footer {
  margin-top: 56px; padding-top: 20px; border-top: 1px solid var(--line);
  color: var(--ink-soft); font-size: 13px;
}

/* ---------- back to top ---------- */
#to-top {
  position: fixed; right: 22px; bottom: 22px; z-index: 40;
  width: 42px; height: 42px; display: grid; place-items: center;
  background: var(--green); color: var(--on-accent); border-radius: 50%;
  text-decoration: none; font-size: 18px; box-shadow: 0 4px 14px rgba(0, 0, 0, .22);
  opacity: 0; pointer-events: none; transition: opacity .2s;
}
#to-top.show { opacity: .92; pointer-events: auto; }

/* ---------- mobile ---------- */
#toc-toggle { display: none; }

@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; gap: 0; padding: 0 16px 60px; }
  #toc-toggle {
    display: block; position: sticky; top: 0; z-index: 50;
    width: 100%; margin: 0; padding: 13px 16px;
    background: var(--green); color: var(--on-accent); border: 0;
    font: 600 14px/1 system-ui, -apple-system, "Segoe UI", sans-serif;
    text-align: left; cursor: pointer;
  }
  #toc-toggle::after { content: " ▾"; }
  #toc-toggle[aria-expanded="true"]::after { content: " ▴"; }
  #toc {
    position: sticky; top: 42px; z-index: 45;
    max-height: 60vh; padding: 12px 10px;
    background: var(--paper); border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow);
  }
  #toc[hidden] { display: none; }
  main { padding-top: 20px; }
  .sub { padding: 18px 16px; border-radius: 10px; }
  .banner { padding: 38px 20px 32px; }
  html { scroll-padding-top: 52px; }
}

/* ---------- theme toggle ---------- */
.banner-inner { position: relative; }
#theme-toggle {
  position: absolute; top: 0; right: 0;
  display: flex; align-items: center; gap: 7px;
  padding: 8px 14px; border-radius: 999px; cursor: pointer;
  background: rgba(255, 248, 230, .14); color: var(--banner-ink);
  border: 1px solid rgba(255, 248, 230, .34);
  font: 600 13px/1 system-ui, -apple-system, "Segoe UI", sans-serif;
  transition: background .15s, transform .15s;
}
#theme-toggle:hover { background: rgba(255, 248, 230, .26); }
#theme-toggle:active { transform: scale(.96); }
#theme-toggle .icon { font-size: 15px; line-height: 1; }
:root[data-theme="dark"] #theme-toggle,
:root[data-theme="light"] #theme-toggle { border-style: solid; }

@media (max-width: 900px) {
  #theme-toggle { position: static; margin-bottom: 16px; }
  .banner-inner { display: flex; flex-direction: column; align-items: flex-start; }
}