/* 水墨本 V3：线装册页。
   订口在左，书耳在右，卷首竖排题签，一篇一叶。
   禁止 hero 双栏、五站胶囊、胶带 tilt、sticky 数字条。
   断网可读：霞鹜文楷自托管。无深色模式，无滚动动效。 */

@font-face {
  font-family: "LXGW WenKai";
  src: url("vendor/fonts/LXGWWenKai-Regular.ttf") format("truetype");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "LXGW WenKai";
  src: url("vendor/fonts/LXGWWenKai-Medium.ttf") format("truetype");
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}

:root {
  --paper: #F5F1E8;
  --paper-deep: #EDE6D8;
  --silk: #E4D9C6;
  --jiao: #1C1E22;
  --nong: #30343A;
  --dan: #5E6166;
  --fei: #8A8680;
  --line: rgba(48, 52, 58, 0.18);
  --line-soft: rgba(48, 52, 58, 0.1);
  --cinnabar: #8B2E2E;
  --cinnabar-ink: #6E2424;
  --prose: 34em;
  --page: 44rem;
  --display: "LXGW WenKai", "Kaiti SC", "STKaiti", "KaiTi", "楷体", serif;
  --serif: "LXGW WenKai", "Songti SC", "STSong", "Noto Serif SC", "SimSun", Georgia, serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --s1: 4px;
  --s2: 8px;
  --s3: 12px;
  --s4: 16px;
  --s5: 24px;
  --s6: 32px;
  --s7: 48px;
  --s8: 64px;
  --s9: 96px;
  --s10: 128px;
}

* { box-sizing: border-box; }

html {
  color-scheme: light;
  scrollbar-color: var(--fei) var(--paper);
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--nong);
  font-family: var(--serif);
  font-weight: 400;
  font-size: 18px;
  line-height: 2.05;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.18;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='220' height='220'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='.72' numOctaves='4' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.28  0 0 0 0 0.24  0 0 0 0 0.18  0 0 0 .42 0'/></filter><rect width='100%' height='100%' filter='url(%23n)'/></svg>");
}

::selection {
  background: rgba(139, 46, 46, 0.16);
  color: var(--jiao);
}

a { color: var(--cinnabar-ink); text-underline-offset: 3px; }
a:hover { color: var(--cinnabar); }

:focus-visible {
  outline: 1px solid var(--cinnabar);
  outline-offset: 3px;
}

.skip {
  position: absolute;
  left: -999px;
  top: 8px;
}
.skip:focus {
  left: 44px;
  z-index: 80;
  background: var(--paper);
  padding: 6px 12px;
  color: var(--jiao);
  border: 1px solid var(--cinnabar);
}

/* —— 线装订口：四眼一线，不是顶栏 —— */
.binding {
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  width: 28px;
  z-index: 12;
  background: linear-gradient(90deg, #E2D6C0 0%, var(--paper) 86%);
  border-right: 1px solid var(--line-soft);
}
.binding::after {
  content: "";
  position: absolute;
  left: 13px;
  top: 11%;
  bottom: 11%;
  width: 1px;
  background: var(--nong);
  opacity: 0.28;
}
.binding i {
  position: absolute;
  left: 9px;
  width: 9px;
  height: 9px;
  border: 1.5px solid var(--nong);
  border-radius: 50%;
  background: var(--paper-deep);
  z-index: 1;
}
.binding i:nth-child(1) { top: 12%; }
.binding i:nth-child(2) { top: 37%; }
.binding i:nth-child(3) { top: 62%; }
.binding i:nth-child(4) { top: 87%; }

/* —— 书耳：三方印，不是胶囊 —— */
.ears {
  position: fixed;
  right: 14px;
  top: 22%;
  z-index: 20;
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.ear {
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border: 1.5px solid var(--cinnabar);
  outline: 1px solid color-mix(in srgb, var(--cinnabar) 50%, transparent);
  outline-offset: 2px;
  color: var(--cinnabar);
  text-decoration: none;
  font-family: var(--display);
  font-size: 13px;
  font-weight: 500;
  background: var(--paper);
  line-height: 1;
}
.ear.is-on {
  background: var(--cinnabar);
  color: var(--paper);
}
@media (hover: hover) {
  .ear:hover { background: color-mix(in srgb, var(--cinnabar) 12%, var(--paper)); }
  .ear.is-on:hover { background: var(--cinnabar); color: var(--paper); }
}


.ear.ear-back {
  margin-top: 10px;
  background: transparent;
  color: var(--cinnabar-ink);
  border: 1px solid var(--cinnabar);
  box-shadow: none;
  font-size: 15px;
}
.ear.ear-back:hover {
  background: rgba(139, 46, 46, 0.08);
  color: var(--cinnabar);
}

.page {
  position: relative;
  z-index: 1;
  width: min(var(--page), calc(100% - 88px));
  margin: 0 auto;
  padding: 0 0 var(--s10);
}

/* —— 卷首：右缘竖排题签，左大留白 —— */
.frontis {
  min-height: 100svh;
  display: flex;
  justify-content: flex-end;
  align-items: center;
  padding: 10vh 4% 8vh 8%;
}
.slip {
  writing-mode: vertical-rl;
  height: min(80vh, 42rem);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2rem;
}
.slip h1,
.slip .vol,
.slip .sub {
  white-space: nowrap;
}
.slip h1 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(2rem, 4vw, 2.9rem);
  font-weight: 500;
  letter-spacing: 0.22em;
  line-height: 1.2;
  color: var(--jiao);
}
.slip .vol {
  margin: 0;
  font-family: var(--display);
  font-size: 0.95rem;
  letter-spacing: 0.38em;
  color: var(--cinnabar);
  font-weight: 500;
}
.slip-tail {
  display: flex;
  flex-direction: row;
  align-items: flex-start;
  gap: 1.5rem;
}
.slip .sub {
  margin: 0;
  font-family: var(--display);
  font-size: 1.05rem;
  letter-spacing: 0.24em;
  color: var(--dan);
  padding-block-start: 3.2em;
}
.yin {
  writing-mode: horizontal-tb;
  flex: 0 0 auto;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 2px solid var(--cinnabar);
  outline: 1px solid var(--cinnabar);
  outline-offset: 3px;
  color: var(--cinnabar);
  font-family: var(--display);
  font-size: 18px;
  font-weight: 500;
  background: color-mix(in srgb, var(--paper) 88%, var(--cinnabar) 6%);
  letter-spacing: 0;
}

/* —— 插页立轴：天杆地杆，无 tilt、无胶带 —— */
.axis {
  margin: var(--s7) auto var(--s5);
  max-width: 36rem;
  padding: 10px 12px 14px;
  background: var(--silk);
  border-top: 3px solid var(--jiao);
  border-bottom: 3px solid var(--jiao);
  border-left: 0;
  border-right: 0;
}
.axis.cover {
  max-width: 19rem;
  margin-top: 0;
  margin-bottom: var(--s8);
}
.axis img {
  display: block;
  width: 100%;
  height: auto;
  background: var(--paper);
  vertical-align: middle;
}
.axis figcaption {
  margin: 10px 2px 0;
  color: var(--dan);
  font-family: var(--display);
  font-size: 13px;
  letter-spacing: 0.08em;
  line-height: 1.55;
  text-align: right;
}

.open .path {
  text-indent: 0;
  color: var(--dan);
  font-size: 0.95em;
  margin-bottom: var(--s4);
  padding-bottom: var(--s3);
  border-bottom: 1px solid var(--line-soft);
}
.open {
  max-width: var(--prose);
  margin: 0 auto var(--s8);
}
.open p {
  margin: 0 0 1.1em;
  text-indent: 2em;
  text-wrap: pretty;
}

/* —— 目次：一、二、三，不是横向数字条 —— */
.toc {
  max-width: 22rem;
  margin: 0 auto var(--s10);
  padding-top: var(--s4);
}
.toc h2 {
  margin: 0 0 var(--s5);
  font-family: var(--display);
  font-size: 1.05rem;
  font-weight: 500;
  letter-spacing: 0.46em;
  color: var(--cinnabar);
}
.toc ol {
  margin: 0;
  padding: 0;
  list-style: none;
}
.toc a {
  display: grid;
  grid-template-columns: 2.1em 1fr;
  gap: 0.7rem;
  padding: 0.5rem 0 0.55rem;
  text-decoration: none;
  color: var(--nong);
  border-bottom: 1px dotted var(--line);
  font-size: 17px;
}
@media (hover: hover) {
  .toc a:hover { color: var(--cinnabar-ink); }
}
.toc .n {
  color: var(--cinnabar);
  font-family: var(--display);
  font-weight: 500;
}

/* —— 一篇一叶 —— */
.leaf {
  position: relative;
  max-width: var(--prose);
  margin: 0 auto var(--s10);
  padding-top: var(--s6);
}
.leaf + .leaf {
  border-top: 1px solid var(--line-soft);
}
.leaf h2 {
  margin: 0 0 1.5em;
  font-family: var(--display);
  font-size: clamp(1.45rem, 2.4vw, 1.85rem);
  font-weight: 500;
  letter-spacing: 0.06em;
  line-height: 1.35;
  color: var(--jiao);
  text-wrap: balance;
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
}
.leaf h2 .n {
  flex: 0 0 auto;
  color: var(--cinnabar);
  font-size: 0.72em;
  letter-spacing: 0.12em;
}
.leaf p {
  margin: 0 0 1.12em;
  text-indent: 2em;
  text-wrap: pretty;
}
.leaf p.flush,
.leaf .see {
  text-indent: 0;
}

.note {
  writing-mode: vertical-rl;
  position: absolute;
  right: calc(100% + 1.4rem);
  top: 5.2rem;
  color: var(--dan);
  font-family: var(--display);
  font-size: 13px;
  letter-spacing: 0.22em;
  height: 9.5em;
  line-height: 1.2;
}

/* 匾额：一句闲话，不是术语框 */
.plaque {
  margin: 1.6rem 0 1.8rem 12%;
  padding: 0;
  max-width: 16em;
  font-family: var(--display);
  font-size: 1.18rem;
  line-height: 1.55;
  letter-spacing: 0.08em;
  color: var(--jiao);
  text-indent: 0;
}
.plaque::before {
  content: "";
  display: block;
  width: 1.5rem;
  height: 1px;
  background: var(--cinnabar);
  margin-bottom: 0.75rem;
}

.see {
  display: inline-block;
  margin-top: 0.4rem;
  font-family: var(--display);
  font-size: 13.5px;
  letter-spacing: 0.08em;
  color: var(--dan);
  text-decoration: none;
  border-bottom: 1px dotted var(--line);
}
@media (hover: hover) {
  .see:hover { color: var(--cinnabar-ink); border-bottom-style: solid; }
}

code {
  font-family: var(--mono);
  font-size: 0.84em;
  background: transparent;
  border-bottom: 1px dotted var(--line);
  padding: 0 0.12em;
}

.colophon {
  max-width: var(--prose);
  margin: var(--s8) auto 0;
  padding-top: var(--s6);
  border-top: 1px solid var(--nong);
  color: var(--dan);
  font-family: var(--display);
  font-size: 15px;
  line-height: 1.9;
}
.colophon p {
  margin: 0 0 0.7em;
  text-indent: 2em;
}
.colophon p.flush { text-indent: 0; }

@media (max-width: 860px) {
  .note {
    writing-mode: horizontal-tb;
    position: static;
    height: auto;
    letter-spacing: 0.14em;
    margin: -0.6em 0 1.4em;
    font-size: 13px;
  }
  .page { width: calc(100% - 72px); }
}

@media (max-width: 640px) {
  body { font-size: 17px; }
  .binding {
    width: 100%;
    height: 10px;
    bottom: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line-soft);
    background: linear-gradient(180deg, #E2D6C0 0%, var(--paper) 100%);
  }
  .binding::after {
    left: 10%;
    right: 10%;
    top: 4px;
    bottom: auto;
    width: auto;
    height: 1px;
  }
  .binding i {
    top: 0;
    left: auto;
  }
  .binding i:nth-child(1) { left: 12%; }
  .binding i:nth-child(2) { left: 37%; }
  .binding i:nth-child(3) { left: 62%; }
  .binding i:nth-child(4) { left: 87%; }
  .ears {
    position: static;
    flex-direction: row;
    justify-content: flex-end;
    padding: 22px 8px 0;
    gap: 12px;
  }
  .page {
    width: calc(100% - 32px);
    padding-bottom: 80px;
  }
  .frontis {
    min-height: auto;
    padding: 8vh 4% 6vh;
    justify-content: center;
  }
  .slip {
    height: auto;
    max-height: none;
  }
  .slip h1 { font-size: clamp(1.7rem, 8vw, 2.2rem); }
  .axis.cover { max-width: 16rem; }
  .plaque { margin-left: 0; }
}

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