/* R3.1 视觉系统；本候选仅使用系统字体，不嵌入字体文件。 */
:root {
  --paper: #f3ecdc;        /* 纸 */
  --paper-deep: #e8dec6;   /* 题签、书签底 */
  --paper-edge: #d9ccb0;   /* 纸边、分隔 */
  --ink: #2b2620;          /* 墨 */
  --ink-soft: #5b5248;     /* 淡墨：书目信息、导读 */
  --wood: #7a5a3a;         /* 木刻版框 */
  --wood-light: #a88a68;
  --cinnabar: #a3342a;     /* 朱砂：印章、选段标记、当前位置 */
  --slate: #4c5a58;        /* 青灰：馆藏刊本 */
  --focus: #1f5f8b;

  --serif: "Songti SC", "STSong", "SimSun", "Noto Serif SC", serif;
  --sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;

  --measure: 34em;
  --gutter: 16px;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.85;
  letter-spacing: 0.02em;
}
a { color: var(--ink); text-decoration-color: var(--wood-light); text-underline-offset: 0.25em; }
a:hover { color: var(--cinnabar); text-decoration-color: var(--cinnabar); }
:focus-visible { outline: 2px solid var(--focus); outline-offset: 3px; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: var(--gutter); top: 8px; background: var(--paper); padding: 4px 8px; z-index: 10; }

/* —— 页眉：藏书楼匾额 —— */
.site-head {
  border-bottom: 3px double var(--wood);
  background: var(--paper-deep);
}
.site-head .inner {
  max-width: 1120px; margin: 0 auto; padding: 10px var(--gutter);
  display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap;
}
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.seal {
  width: 34px; height: 34px; flex: none;
  border: 2px solid var(--cinnabar); color: var(--cinnabar);
  display: grid; place-items: center;
  font-size: 13px; line-height: 1.05; font-weight: 700; letter-spacing: 0;
  text-align: center; border-radius: 3px;
}
.brand-name { font-size: 19px; font-weight: 700; letter-spacing: 0.08em; color: var(--ink); }
.nav { display: flex; gap: 4px 18px; flex-wrap: wrap; font-size: 15px; }
.nav a { text-decoration: none; padding: 4px 0; border-bottom: 2px solid transparent; }
.nav a[aria-current="page"] { border-bottom-color: var(--cinnabar); color: var(--cinnabar); }

/* —— 主体 —— */
main { max-width: 1120px; margin: 0 auto; padding: 28px var(--gutter) 48px; }
.hero { max-width: var(--measure); margin: 8px auto 32px; text-align: center; }
.hero h1 { font-size: 30px; letter-spacing: 0.16em; margin: 0 0 6px; font-weight: 700; }
.hero .tagline { font-size: 18px; color: var(--cinnabar); letter-spacing: 0.12em; margin: 0 0 14px; }
.hero .lead { color: var(--ink-soft); margin: 0; }
.rule-orn { display: flex; align-items: center; gap: 10px; justify-content: center; color: var(--wood); margin: 18px 0 0; }
.rule-orn::before, .rule-orn::after { content: ""; height: 1px; width: 64px; background: var(--wood-light); }

.section-title {
  font-size: 15px; letter-spacing: 0.3em; color: var(--wood);
  margin: 0 0 12px; display: flex; align-items: center; gap: 10px;
}
.section-title::after { content: ""; flex: 1; height: 1px; background: var(--paper-edge); }

/* —— 书卡：题签＋版框 —— */
.shelf { display: grid; gap: 28px; }
.book {
  position: relative;
  border: 2px solid var(--wood);
  outline: 1px solid var(--wood-light); outline-offset: -7px;   /* 木刻双栏版框 */
  background: #f7f1e3;
  padding: 22px 18px 18px;
}
.book-label {                                   /* 线装题签 */
  display: inline-block;
  background: var(--paper-deep); border: 1px solid var(--wood-light);
  padding: 2px 12px; font-size: 20px; font-weight: 700; letter-spacing: 0.1em;
  margin: 0 0 8px;
}
.book-meta { font-size: 14px; color: var(--ink-soft); margin: 0 0 14px; line-height: 1.7; }
.book-meta .sep { color: var(--wood-light); padding: 0 4px; }

.tag {
  display: inline-block; font-family: var(--sans); font-size: 12px; letter-spacing: 0.1em;
  padding: 0 7px; border-radius: 2px; vertical-align: 2px; margin-right: 6px; line-height: 1.7;
  border: 1px solid currentColor;
}
.tag-excerpt { color: var(--cinnabar); }
.tag-guide { color: var(--ink-soft); }
.tag-etext { color: var(--wood); }
.tag-print { color: var(--slate); }

.excerpt {
  margin: 0 0 14px; padding: 14px 16px 14px 18px;
  border-left: 3px solid var(--cinnabar);
  background: var(--paper);
  font-size: 19px; line-height: 2; letter-spacing: 0.06em;
}
.excerpt p { margin: 0; }
.excerpt .label { display: block; margin-bottom: 6px; }
.guide { color: var(--ink-soft); margin: 0 0 16px; font-size: 16px; }
.guide .label { margin-right: 2px; }

.actions { display: flex; flex-wrap: wrap; gap: 10px 14px; align-items: center; }
.btn {
  display: inline-block; text-decoration: none;
  border: 1px solid var(--ink); padding: 6px 16px; font-size: 15px; letter-spacing: 0.08em;
  background: var(--ink); color: var(--paper); border-radius: 2px;
}
.btn:hover { background: var(--cinnabar); border-color: var(--cinnabar); color: #fff; }
.btn-line { background: transparent; color: var(--ink); }
.btn-line:hover { background: transparent; color: var(--cinnabar); }
.src-link { font-size: 15px; }
.ext::after { content: " ↗"; font-family: var(--sans); font-size: 12px; color: var(--ink-soft); }

.home-more { text-align: center; margin: 36px 0 0; }

/* —— 目录 —— */
.toc-jump { display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 28px; justify-content: center; }
.toc-jump a {
  text-decoration: none; font-size: 14px; padding: 2px 12px;
  border: 1px solid var(--wood-light); background: var(--paper-deep); border-radius: 2px;
}
.catalog { max-width: 820px; margin: 0 auto; }
.cat-group { margin: 0 0 30px; scroll-margin-top: 16px; }
.entry {
  border-top: 1px solid var(--paper-edge); padding: 16px 0 14px;
  display: grid; grid-template-columns: 1fr; gap: 4px; scroll-margin-top: 16px;
}
.entry:target { background: linear-gradient(90deg, rgba(163,52,42,0.08), transparent 70%); }
.entry h3 { margin: 0; font-size: 18px; letter-spacing: 0.06em; }
.entry h3 .pian { font-weight: 400; color: var(--ink-soft); font-size: 15px; }
.entry .q { margin: 2px 0; font-size: 16px; }
.entry .note { margin: 0; font-size: 14px; color: var(--ink-soft); }
.entry .links { font-size: 14px; display: flex; flex-wrap: wrap; gap: 4px 14px; }
.entry .anchor-id { font-family: var(--sans); font-size: 11px; color: var(--wood-light); }

/* —— 选读页 —— */
.reading { display: grid; gap: 28px; }
.crumbs { font-size: 14px; color: var(--ink-soft); margin: 0 0 14px; }
.crumbs a { color: var(--ink-soft); }
.read-head h1 { font-size: 26px; letter-spacing: 0.1em; margin: 0 0 4px; }
.read-head .juan { color: var(--cinnabar); letter-spacing: 0.12em; margin: 0 0 6px; }
.read-head .meta { font-size: 14px; color: var(--ink-soft); margin: 0; }
.leaf {                                           /* 版面：上下栏线＋双边框 */
  border: 2px solid var(--wood); outline: 1px solid var(--wood-light); outline-offset: -7px;
  background: #f7f1e3; padding: 26px 22px;
}
.leaf .excerpt { font-size: 20px; border-left-width: 3px; }
.leaf .excerpt p + p { margin-top: 0.6em; }
.punct-note { font-size: 13px; color: var(--ink-soft); margin: 0 0 18px; }
.aside-box { border: 1px solid var(--paper-edge); background: var(--paper-deep); padding: 16px 16px 14px; font-size: 15px; }
.aside-box h2 { font-size: 15px; letter-spacing: 0.2em; color: var(--wood); margin: 0 0 8px; }
.aside-box dl { margin: 0; display: grid; grid-template-columns: 4.5em 1fr; gap: 4px 10px; }
.aside-box dt { color: var(--ink-soft); }
.aside-box dd { margin: 0; }
.src-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }
.src-list li { line-height: 1.6; }
.src-list .why { display: block; font-size: 13px; color: var(--ink-soft); }
.status-pending { color: var(--cinnabar); }

/* —— 页脚 —— */
.site-foot { border-top: 3px double var(--wood); background: var(--paper-deep); font-size: 14px; }
.site-foot .inner { max-width: 1120px; margin: 0 auto; padding: 20px var(--gutter) 28px; text-align: center; }
.foot-links { display: flex; flex-wrap: wrap; gap: 6px 18px; justify-content: center; margin: 0 0 12px; }
.foot-org { margin: 0; color: var(--ink-soft); line-height: 1.8; }

/* —— 占位页 —— */
.placeholder { max-width: var(--measure); margin: 20px auto; text-align: center; color: var(--ink-soft); }

/* —— 桌面 —— */
@media (min-width: 900px) {
  body { font-size: 18px; }
  .hero h1 { font-size: 38px; }
  .shelf { grid-template-columns: 1fr 1fr; gap: 32px; }
  .book { padding: 30px 28px 24px; }
  .reading { grid-template-columns: minmax(0, 1fr) 300px; align-items: start; }
  .reading aside { position: sticky; top: 20px; display: grid; gap: 18px; }
  .leaf { padding: 36px 40px; }
  .entry { grid-template-columns: 11em 1fr; column-gap: 24px; }
  .entry h3 { grid-row: span 4; }
}
@media (max-width: 360px) {
  .brand-name { font-size: 17px; }
  .excerpt { font-size: 18px; padding: 12px 12px 12px 14px; }
  .leaf { padding: 20px 14px; }
}
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; } }

/* 全站工具与说明页的统一外观，保留 R5 各工具结构和脚本。 */
.tool-page { max-width: 860px; }
.tool-page .card { background: #f7f1e3; border-color: var(--paper-edge); color: var(--ink); box-shadow: none; }
.tool-page input, .tool-page select, .tool-page textarea { font: inherit; border-color: var(--wood-light); background: #fffdf8; color: var(--ink); }
.tool-page button, .tool-page .btn { font: inherit; background: var(--ink); color: var(--paper); border-color: var(--ink); border-radius: 2px; }
.tool-page button:hover, .tool-page .btn:hover { background: var(--cinnabar); border-color: var(--cinnabar); }
.tool-page [role="note"] { background: var(--paper-deep) !important; color: var(--ink) !important; border-bottom: 1px solid var(--paper-edge); }
.site-foot a { color: var(--ink); }
main > h1 { line-height: 1.35; }
@media (max-width: 600px) { .site-head .inner { align-items: flex-start; } .nav { gap: 4px 12px; } }

.tool-list { list-style-position: inside; padding: 0; }
.tool-list li { border-top: 1px solid var(--paper-edge); padding: 10px 0; }


/* R3.1 汉风视觉补充：仅绘制线、框与印，不载入字体或图片。 */
.site-head { position: relative; border-bottom: 0; }
.site-head::after,
.site-foot::before {
  content: "";
  display: block;
  height: 12px;
  background: url("/assets/huiwen.svg") repeat-x left center / 24px 12px;
  border-block: 1px solid var(--wood-light);
}
.site-foot { border-top: 0; }
.site-head .seal {
  background: var(--cinnabar);
  color: var(--paper);
  border: 2px solid var(--cinnabar);
  box-shadow: inset 0 0 0 2px var(--paper), inset 0 0 0 4px var(--cinnabar);
  border-radius: 0;
}
.hero::before {
  content: "";
  display: block;
  width: 60px;
  height: 60px;
  margin: 0 auto 12px;
  border: 2px solid var(--wood);
  border-radius: 50%;
  background:
    radial-gradient(circle at center, var(--wood) 0 3px, transparent 3.5px),
    linear-gradient(90deg, transparent 48%, var(--wood-light) 49% 51%, transparent 52%),
    linear-gradient(0deg, transparent 48%, var(--wood-light) 49% 51%, transparent 52%),
    radial-gradient(circle, transparent 48%, var(--wood-light) 49% 51%, transparent 52%);
  box-shadow: inset 0 0 0 5px var(--paper), inset 0 0 0 6px var(--wood-light);
}
.section-title { gap: 12px; }
.section-title::before {
  content: "";
  display: inline-block;
  flex: 0 0 8px;
  width: 8px;
  height: 8px;
  border: 1px solid var(--wood);
  transform: rotate(45deg);
}
.book { border-left: 7px double var(--wood); }
.read-head { text-align: center; }
.read-head::after {
  content: "◁  ───  ◇  ───  ▷";
  display: block;
  margin: 10px auto 0;
  color: var(--wood);
  font-size: 13px;
  letter-spacing: 0.18em;
}
.leaf { position: relative; }
.shelf { grid-template-columns: minmax(0, 1fr); }
@media (min-width: 900px) {
  .shelf { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .book-label {
    writing-mode: vertical-rl;
    text-orientation: upright;
    min-height: 6em;
    padding: 10px 6px;
    letter-spacing: 0.12em;
    vertical-align: top;
  }
  .leaf .excerpt {
    writing-mode: vertical-rl;
    text-orientation: mixed;
    width: min(38rem, 100%);
    height: 28rem;
    overflow-x: auto;
    border-left: 0;
    border-right: 3px solid var(--cinnabar);
    background-color: var(--paper);
    background-image: repeating-linear-gradient(90deg, transparent 0 2.8rem, rgba(163, 52, 42, 0.18) 2.8rem calc(2.8rem + 1px));
    line-height: 2;
    letter-spacing: 0.06em;
  }
  .leaf .excerpt p + p { margin-inline-start: 0.7em; margin-block-start: 0; }
}
@media (max-width: 899px) {
  .shelf { grid-template-columns: minmax(0, 1fr); }
  .book-label { writing-mode: horizontal-tb; text-orientation: mixed; }
  .leaf .excerpt {
    writing-mode: horizontal-tb;
    width: 100%;
    height: auto;
    overflow: visible;
    border-left: 3px solid var(--cinnabar);
    border-right: 0;
    background-image: none;
  }
  .leaf .excerpt p + p { margin-block-start: 0.6em; margin-inline-start: 0; }
}