:root {
  --ink: #14181d;
  --ink-soft: #2a323c;
  --mist: #7a8b9a;
  --wash: #d5dee6;
  --paper: #eef2f5;
  --paper-deep: #e2e8ee;
  --seal: #8f2a2a;
  --gold: #8f7840;
  --ridge-1: #4a5a68;
  --ridge-2: #3a4854;
  --ridge-3: #2b353f;
  --hero-top: #9eb0bf;
  --hero-mid: #6d8193;
  --hero-bot: #2f3b46;
  --shadow: rgba(20, 24, 29, 0.18);
  --max-prose: 42rem;
  --nav-h: 3.5rem;
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(158, 176, 191, 0.35), transparent 60%),
    radial-gradient(900px 500px at 90% 0%, rgba(143, 120, 64, 0.08), transparent 55%),
    linear-gradient(180deg, var(--paper) 0%, var(--paper-deep) 100%);
  font-family: "Noto Serif SC", "Songti SC", "SimSun", serif;
  font-weight: 400;
  line-height: 1.9;
  letter-spacing: 0.02em;
  overflow-x: hidden;
}

.grain {
  pointer-events: none;
  position: fixed;
  inset: 0;
  z-index: 50;
  opacity: 0.045;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
}

a {
  color: inherit;
  text-decoration: none;
}

code {
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: 0.85em;
  background: rgba(20, 24, 29, 0.06);
  padding: 0.1em 0.35em;
  border-radius: 0.25rem;
}

/* —— Nav —— */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 40;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.25rem;
  background: transparent;
  transition: background 0.4s var(--ease-out), box-shadow 0.4s var(--ease-out), color 0.3s ease;
  color: rgba(255, 255, 255, 0.92);
}

.site-nav.is-solid {
  background: rgba(238, 242, 245, 0.88);
  backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 rgba(20, 24, 29, 0.08);
  color: var(--ink);
}

.nav-brand {
  font-family: "Ma Shan Zheng", cursive;
  font-size: 1.55rem;
  letter-spacing: 0.12em;
}

.toc-toggle {
  appearance: none;
  border: 1px solid currentColor;
  background: transparent;
  color: inherit;
  font-family: "ZCOOL XiaoWei", "Noto Serif SC", serif;
  font-size: 0.95rem;
  letter-spacing: 0.2em;
  padding: 0.35rem 0.85rem;
  cursor: pointer;
  opacity: 0.9;
}

.toc-toggle:hover {
  opacity: 1;
}

@media (min-width: 1100px) {
  .toc-toggle {
    display: none;
  }
}

/* —— Hero —— */
.hero {
  position: relative;
  min-height: 100vh;
  min-height: 100dvh;
  display: grid;
  place-items: center;
  overflow: hidden;
  color: #f4f7fa;
  isolation: isolate;
}

.hero-sky {
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(180deg, var(--hero-top) 0%, var(--hero-mid) 42%, var(--hero-bot) 100%);
}

.mist {
  position: absolute;
  inset: -20% -10%;
  background:
    radial-gradient(ellipse at 30% 40%, rgba(255, 255, 255, 0.28), transparent 55%),
    radial-gradient(ellipse at 70% 55%, rgba(255, 255, 255, 0.18), transparent 50%);
  filter: blur(28px);
  animation: drift 22s ease-in-out infinite alternate;
}

.mist-b {
  animation-duration: 28s;
  animation-direction: alternate-reverse;
  opacity: 0.7;
}

@keyframes drift {
  from {
    transform: translate3d(-2%, 1%, 0) scale(1.05);
  }
  to {
    transform: translate3d(3%, -2%, 0) scale(1.12);
  }
}

.ridges {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  height: min(52vh, 520px);
}

.ridge {
  fill: var(--ridge-1);
}

.ridge.r2 {
  fill: var(--ridge-2);
}

.ridge.r3 {
  fill: var(--ridge-3);
}

.hero-copy {
  width: min(920px, calc(100% - 2.5rem));
  text-align: center;
  padding: 5rem 0 6rem;
  transform: translateY(1.25rem);
  opacity: 0;
  animation: rise 1.15s var(--ease-out) 0.15s forwards;
}

@keyframes rise {
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

.hero-years {
  margin: 0 0 1.25rem;
  font-family: "ZCOOL XiaoWei", serif;
  font-size: 0.95rem;
  letter-spacing: 0.45em;
  color: rgba(255, 255, 255, 0.78);
}

.hero-brand {
  margin: 0;
  font-family: "Ma Shan Zheng", cursive;
  font-size: clamp(3.4rem, 11vw, 6.5rem);
  font-weight: 400;
  line-height: 1.05;
  letter-spacing: 0.18em;
  text-indent: 0.18em;
  text-shadow: 0 8px 40px rgba(20, 24, 29, 0.25);
}

.hero-subject {
  margin: 1.4rem 0 0;
  font-family: "ZCOOL XiaoWei", serif;
  font-size: clamp(1.35rem, 3.2vw, 1.85rem);
  letter-spacing: 0.28em;
  text-indent: 0.28em;
  color: rgba(255, 255, 255, 0.92);
}

.hero-tagline {
  margin: 1.5rem auto 0;
  max-width: 34rem;
  font-size: 1.02rem;
  line-height: 1.85;
  color: rgba(244, 247, 250, 0.82);
  letter-spacing: 0.06em;
}

.hero-actions {
  margin-top: 2.25rem;
}

.btn-primary {
  display: inline-block;
  padding: 0.85rem 1.8rem;
  border: 1px solid rgba(255, 255, 255, 0.55);
  background: rgba(20, 24, 29, 0.18);
  backdrop-filter: blur(6px);
  font-family: "ZCOOL XiaoWei", serif;
  font-size: 1rem;
  letter-spacing: 0.35em;
  text-indent: 0.35em;
  transition: background 0.3s ease, border-color 0.3s ease, transform 0.3s var(--ease-out);
}

.btn-primary:hover {
  background: rgba(20, 24, 29, 0.35);
  border-color: rgba(255, 255, 255, 0.85);
  transform: translateY(-2px);
}

.hero-scroll {
  position: absolute;
  left: 50%;
  bottom: 1.5rem;
  transform: translateX(-50%);
  width: 1px;
  height: 3rem;
  background: rgba(255, 255, 255, 0.25);
  overflow: hidden;
}

.hero-scroll span {
  display: block;
  width: 100%;
  height: 40%;
  background: rgba(255, 255, 255, 0.85);
  animation: scroll-line 1.8s var(--ease-out) infinite;
}

@keyframes scroll-line {
  0% {
    transform: translateY(-120%);
  }
  100% {
    transform: translateY(280%);
  }
}

/* —— Reading layout —— */
.read-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  width: min(1180px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 3.5rem 0 5rem;
}

@media (min-width: 1100px) {
  .read-layout {
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 3rem;
    align-items: start;
  }
}

.toc-rail {
  display: none;
}

@media (min-width: 1100px) {
  .toc-rail {
    display: block;
    position: sticky;
    top: calc(var(--nav-h) + 1.5rem);
    padding-right: 1rem;
    border-right: 1px solid rgba(20, 24, 29, 0.1);
  }
}

.toc-label {
  margin: 0 0 1rem;
  font-family: "ZCOOL XiaoWei", serif;
  font-size: 0.85rem;
  letter-spacing: 0.35em;
  color: var(--mist);
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.toc-link {
  display: block;
  padding: 0.45rem 0.6rem 0.45rem 0.75rem;
  border-left: 2px solid transparent;
  color: var(--ink-soft);
  font-size: 0.92rem;
  line-height: 1.45;
  letter-spacing: 0.04em;
  transition: color 0.25s ease, border-color 0.25s ease, background 0.25s ease;
}

.toc-link .kicker {
  display: block;
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  color: var(--mist);
  margin-bottom: 0.15rem;
}

.toc-link:hover,
.toc-link.is-active {
  color: var(--ink);
  border-left-color: var(--seal);
  background: rgba(143, 42, 42, 0.05);
}

.toc-link.is-active .kicker {
  color: var(--seal);
}

/* —— Drawer TOC —— */
.toc-drawer {
  position: fixed;
  top: 0;
  right: 0;
  z-index: 45;
  width: min(20rem, 88vw);
  height: 100%;
  background: rgba(238, 242, 245, 0.97);
  box-shadow: -12px 0 40px var(--shadow);
  transform: translateX(105%);
  transition: transform 0.4s var(--ease-out);
}

.toc-drawer.is-open {
  transform: translateX(0);
}

.toc-drawer[hidden] {
  display: block !important;
  visibility: hidden;
  pointer-events: none;
}

.toc-drawer.is-open[hidden] {
  visibility: visible;
  pointer-events: auto;
}

.toc-drawer-inner {
  padding: calc(var(--nav-h) + 1rem) 1.25rem 2rem;
  height: 100%;
  overflow: auto;
}

.toc-backdrop {
  position: fixed;
  inset: 0;
  z-index: 44;
  background: rgba(20, 24, 29, 0.35);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.toc-backdrop.is-open {
  opacity: 1;
}

.toc-backdrop[hidden] {
  display: block !important;
  visibility: hidden;
  pointer-events: none;
}

.toc-backdrop.is-open[hidden] {
  visibility: visible;
  pointer-events: auto;
}

/* —— Manuscript —— */
.manuscript {
  min-width: 0;
}

.chapter {
  margin-bottom: 4.5rem;
  scroll-margin-top: calc(var(--nav-h) + 1.25rem);
  opacity: 0;
  transform: translateY(1.5rem);
  transition: opacity 0.8s var(--ease-out), transform 0.8s var(--ease-out);
}

.chapter.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.chapter-header {
  margin-bottom: 2rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid rgba(20, 24, 29, 0.12);
}

.chapter-kicker {
  margin: 0 0 0.5rem;
  font-family: "ZCOOL XiaoWei", serif;
  font-size: 0.9rem;
  letter-spacing: 0.4em;
  color: var(--seal);
}

.chapter-title {
  margin: 0;
  font-family: "ZCOOL XiaoWei", serif;
  font-size: clamp(1.7rem, 3.5vw, 2.25rem);
  font-weight: 400;
  letter-spacing: 0.12em;
  line-height: 1.35;
  color: var(--ink);
}

.section {
  margin-bottom: 2.25rem;
}

.section-heading {
  margin: 0 0 1rem;
  font-family: "ZCOOL XiaoWei", serif;
  font-size: 1.2rem;
  font-weight: 400;
  letter-spacing: 0.14em;
  color: var(--ink-soft);
}

.prose {
  max-width: var(--max-prose);
}

.prose p {
  margin: 0 0 1.15rem;
  font-size: 1.05rem;
  text-align: justify;
  text-justify: inter-ideograph;
}

.prose p:last-child {
  margin-bottom: 0;
}

.tenets {
  list-style: none;
  margin: 1.25rem 0 1.5rem;
  padding: 0;
  display: grid;
  gap: 0.85rem;
  max-width: var(--max-prose);
}

.tenet {
  padding: 0.85rem 0 0.85rem 1rem;
  border-left: 2px solid var(--gold);
}

.tenet strong {
  display: block;
  font-family: "ZCOOL XiaoWei", serif;
  font-weight: 400;
  letter-spacing: 0.2em;
  margin-bottom: 0.25rem;
  color: var(--ink);
}

.tenet span {
  color: var(--ink-soft);
  font-size: 0.98rem;
}

/* —— Footer —— */
.site-footer {
  border-top: 1px solid rgba(20, 24, 29, 0.1);
  padding: 2.5rem 1.25rem 3.5rem;
  text-align: center;
  color: var(--mist);
  font-size: 0.92rem;
}

.site-footer p {
  margin: 0.35rem 0;
}

.footer-hint {
  font-size: 0.85rem;
  opacity: 0.85;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .mist,
  .hero-scroll span,
  .hero-copy,
  .chapter {
    animation: none !important;
    transition: none !important;
    opacity: 1 !important;
    transform: none !important;
  }
}