:root {
  color-scheme: light;
  --paper: #fbfaf7;
  --surface: #fffefa;
  --ink: #111827;
  --muted: #5b6574;
  --rule: #d6d9e0;
  --arc: #0b5cad;
  --arc-tint: #eaf3fb;
  --arc-1: #0b5cad;
  --arc-1-tint: #eaf3fb;
  --arc-2: #a75a12;
  --arc-2-tint: #fbf1e4;
  --arc-3: #1e7a63;
  --arc-3-tint: #e8f6f1;
  --arc-4: #a33a52;
  --arc-4-tint: #fbe9ee;
  --arc-5: #5c4b8a;
  --arc-5-tint: #f0ecfa;
  --arc-6: #0b5cad;
  --arc-6-tint: #eaf3fb;
}

* { box-sizing: border-box; }
html { background: var(--paper); }
body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 94% 9%, color-mix(in srgb, var(--arc-tint) 90%, transparent), transparent 26rem),
    linear-gradient(180deg, var(--paper), color-mix(in srgb, var(--arc-tint) 28%, var(--paper)));
  font: 17px/1.78 Inter, "PingFang SC", "Noto Sans SC", sans-serif;
}
.arc-1 { --arc: var(--arc-1); --arc-tint: var(--arc-1-tint); }
.arc-2 { --arc: var(--arc-2); --arc-tint: var(--arc-2-tint); }
.arc-3 { --arc: var(--arc-3); --arc-tint: var(--arc-3-tint); }
.arc-4 { --arc: var(--arc-4); --arc-tint: var(--arc-4-tint); }
.arc-5 { --arc: var(--arc-5); --arc-tint: var(--arc-5-tint); }
.arc-6 { --arc: var(--arc-6); --arc-tint: var(--arc-6-tint); }
.site-masthead {
  align-items: center;
  display: flex;
  justify-content: space-between;
  min-height: 54px;
  padding: 0 max(28px, calc((100vw - 1120px) / 2));
  background: rgba(251, 250, 247, 0.88);
  border-bottom: 1px solid rgba(44, 55, 68, 0.12);
  backdrop-filter: blur(12px);
}
.site-masthead a { color: #122235; font: 700 16px/1 Georgia, "Noto Serif SC", serif; text-decoration: none; }
.site-masthead span { color: var(--arc); font: 800 11px/1 ui-monospace, monospace; letter-spacing: 0.12em; }
.reading-shell {
  width: min(900px, calc(100% - 40px));
  min-height: calc(100vh - 110px);
  margin: 44px auto 96px;
  padding: 54px 64px 88px;
  background: rgba(255, 254, 250, 0.94);
  border: 1px solid rgba(44, 55, 68, 0.12);
  border-top: 6px solid var(--arc);
  box-shadow: 0 24px 64px rgba(35, 42, 52, 0.08);
}
.arc-ribbon {
  align-items: baseline;
  display: flex;
  gap: 10px;
  margin: -20px 0 42px;
  padding: 11px 14px;
  color: var(--arc);
  background: var(--arc-tint);
  border-left: 4px solid var(--arc);
}
.arc-ribbon span, .arc-ribbon small { font: 800 11px/1.3 ui-monospace, monospace; letter-spacing: 0.08em; }
.arc-ribbon strong { font-size: 14px; }
.arc-ribbon small { margin-left: auto; color: var(--muted); }
h1, h2, h3 { line-height: 1.3; text-wrap: balance; }
h1 { margin: 0 0 32px; font: 700 42px/1.2 "Noto Serif SC", "Songti SC", serif; }
h2 { margin-top: 52px; padding-top: 12px; border-top: 1px solid color-mix(in srgb, var(--arc) 24%, var(--rule)); }
h3 { margin-top: 36px; }
a { color: var(--arc); text-underline-offset: 0.18em; }
blockquote { margin: 28px 0; padding: 16px 20px; background: var(--arc-tint); border-left: 4px solid var(--arc); }
code { font-family: "SFMono-Regular", Consolas, monospace; font-size: 0.9em; }
pre { overflow-x: auto; padding: 20px; background: #111827; color: #f8fafc; border-radius: 8px; }
table { width: 100%; border-collapse: collapse; margin: 24px 0; font-size: 0.94em; }
th, td { padding: 10px 12px; border: 1px solid var(--rule); text-align: left; vertical-align: top; }
th { background: var(--arc-tint); }
img { display: block; max-width: 100%; height: auto; margin: 32px auto; padding: 8px; background: #fff; border: 1px solid rgba(44, 55, 68, 0.1); }
.agent-callout { display: flex; align-items: center; justify-content: space-between; gap: 18px; margin-top: 56px; padding: 18px 20px; background: var(--arc-tint); border-left: 4px solid var(--arc); }
.agent-callout strong { color: var(--arc); font: 800 12px/1.3 ui-monospace, monospace; letter-spacing: 0.08em; text-transform: uppercase; }
.agent-callout a { font-weight: 750; }

.book-cover-page { --arc: #0b5cad; --arc-tint: #eaf3fb; }
.book-cover-page .site-masthead { position: relative; z-index: 5; }
.book-cover {
  isolation: isolate;
  overflow: hidden;
  position: relative;
  min-height: 640px;
  padding: 96px max(28px, calc((100vw - 1120px) / 2)) 76px;
  background:
    radial-gradient(circle at 88% 16%, rgba(30, 122, 99, 0.14), transparent 27%),
    linear-gradient(135deg, #eaf3fb 0%, #fbfaf7 51%, #fbf1e4 100%);
  border-bottom: 1px solid rgba(44, 55, 68, 0.12);
}
.book-cover__content { position: relative; z-index: 2; width: 100%; max-width: 1120px; min-width: 0; }
.book-cover__eyebrow, .arc-map__heading p { margin: 0; color: #0b5cad; font: 800 12px/1.2 ui-monospace, monospace; letter-spacing: 0.16em; }
.book-cover h1 { max-width: 900px; margin: 18px 0 24px; color: #122235; font-size: clamp(64px, 10vw, 128px); line-height: 0.88; letter-spacing: -0.065em; }
.book-cover__subtitle { max-width: 760px; margin: 0; color: #0b5cad; font: 700 clamp(24px, 3.4vw, 44px)/1.2 "Noto Serif SC", "Songti SC", serif; }
.book-cover__promise { max-width: 720px; margin: 24px 0 0; color: #475569; font-size: 17px; overflow-wrap: anywhere; }
.book-cover__actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 34px; }
.cover-button { padding: 11px 16px; color: #122235; background: rgba(255,255,255,0.62); border: 1px solid rgba(18,34,53,0.22); font-size: 14px; font-weight: 750; text-decoration: none; }
.cover-button--primary { color: #fff; background: #0b5cad; border-color: #0b5cad; }
.book-cover__rail { display: grid; grid-template-columns: repeat(6, minmax(26px, 92px)); gap: 8px; margin-top: 64px; }
.book-cover__rail i { height: 8px; background: var(--arc-color); }
.cover-orbit { position: absolute; z-index: 1; border: 14px solid rgba(11, 92, 173, 0.1); border-radius: 50%; }
.cover-orbit--one { width: 520px; height: 520px; right: -120px; top: -140px; }
.cover-orbit--two { width: 300px; height: 300px; right: 16%; bottom: -210px; border-color: rgba(167, 90, 18, 0.1); }
.arc-map { padding: 72px max(28px, calc((100vw - 1120px) / 2)) 88px; background: #fbfaf7; }
.arc-map__heading { max-width: 780px; }
.arc-map__heading h2 { margin: 10px 0 36px; padding: 0; border: 0; font: 700 clamp(30px, 4.2vw, 52px)/1.15 "Noto Serif SC", "Songti SC", serif; }
.arc-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.arc-card { --arc-color: var(--arc-1); display: flex; flex-direction: column; min-height: 220px; padding: 22px; color: #122235; background: #fff; border: 1px solid rgba(44,55,68,0.13); border-top: 6px solid var(--arc-color); text-decoration: none; transition: transform 160ms ease, box-shadow 160ms ease; }
.arc-card:hover { transform: translateY(-3px); box-shadow: 0 18px 34px rgba(35,42,52,0.09); }
.arc-card span { color: var(--arc-color); font: 800 11px/1.3 ui-monospace, monospace; letter-spacing: 0.08em; }
.arc-card strong { margin-top: 20px; font: 700 22px/1.25 "Noto Serif SC", "Songti SC", serif; }
.arc-card small { margin-top: auto; padding-top: 26px; color: #5b6574; font-size: 14px; line-height: 1.6; }
.arc-card--1 { --arc-color: var(--arc-1); }
.arc-card--2 { --arc-color: var(--arc-2); }
.arc-card--3 { --arc-color: var(--arc-3); }
.arc-card--4 { --arc-color: var(--arc-4); }
.arc-card--5 { --arc-color: var(--arc-5); }
.arc-card--6 { --arc-color: var(--arc-6); }
.book-cover-page .reading-shell { margin-top: 0; border-top: 1px solid rgba(44,55,68,0.12); box-shadow: none; }
.book-cover-page .reading-shell > h1:first-child { display: none; }
@media (max-width: 700px) {
  body { font-size: 16px; }
  .site-masthead { padding: 0 18px; }
  .site-masthead span { max-width: 52%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .reading-shell { width: calc(100% - 24px); margin: 20px auto 48px; padding: 34px 20px 60px; }
  .arc-ribbon { align-items: flex-start; flex-wrap: wrap; margin-bottom: 30px; }
  .arc-ribbon small { width: 100%; margin-left: 0; }
  h1 { font-size: 32px; }
  table { display: block; overflow-x: auto; }
  .book-cover { min-height: 560px; padding: 70px 22px 52px; }
  .book-cover h1 { font-size: clamp(54px, 18vw, 78px); }
  .book-cover__promise { max-width: calc(100vw - 44px); line-height: 1.7; }
  .book-cover__rail { width: 100%; grid-template-columns: repeat(6, minmax(0, 1fr)); margin-top: 46px; }
  .arc-map { padding: 52px 18px 64px; }
  .arc-grid { grid-template-columns: 1fr; }
  .arc-card { min-height: 180px; }
  .agent-callout { align-items: flex-start; flex-direction: column; gap: 6px; }
}