/* =========================================================================
   yhxx · 私人藏书室
   不是博客。是图书馆。
   ========================================================================= */

/* --- 设计令牌 ----------------------------------------------------------- */

:root {
  /* 纸与墨 */
  --paper:        #E8DCC0;  /* 纸面主色，温暖陈旧 */
  --paper-edge:   #D4C6A8;  /* 卡片描边 */
  --paper-shadow: #C9B996;  /* 卡片硬阴影 */
  --paper-deep:   #DCCFB0;  /* 区块分隔的更浅纸 */
  --ink:          #1F1B16;  /* 墨黑主文字 */
  --ink-soft:     #4A4138;  /* 次级文字 */
  --ash:          #6B5D4D;  /* 元信息、分隔线 */

  /* 签名强调 */
  --vermilion:      #9A2A2A;  /* 朱砂红，签名强调 */
  --vermilion-deep: #7A1F1F;  /* 朱砂悬停 */

  /* 辅助 */
  --moss:        #5C6B47;  /* 苔绿，眉批与标签 */
  --moss-soft:   #88976B;

  /* 字体 */
  --font-display: "Source Han Serif SC", "Noto Serif SC", "Songti SC",
                  "STSong", "Cormorant Garamond", "EB Garamond", serif;
  --font-body:    "Source Han Serif SC", "Noto Serif SC", "Songti SC",
                  "STSong", "Spectral", "Crimson Pro", serif;
  --font-mono:    "IBM Plex Mono", "JetBrains Mono", "SF Mono",
                  Consolas, "Liberation Mono", monospace;

  /* 字号阶（modular, ratio ~1.25） */
  --step--2: 0.75rem;     /* 12px - 元信息 */
  --step--1: 0.875rem;    /* 14px - 眉批 */
  --step-0:  1.0625rem;   /* 17px - 摘要 */
  --step-1:  1.1875rem;   /* 19px - 正文 */
  --step-2:  1.4375rem;   /* 23px - 副标题/标题 */
  --step-3:  1.875rem;    /* 30px - 二级标题 */
  --step-4:  2.75rem;     /* 44px - 大标题 */
  --step-5:  4.5rem;      /* 72px - 卷首 */

  /* 节奏 */
  --gutter:      clamp(1.25rem, 4vw, 2.5rem);
  --measure:     38rem;    /* ~620px 阅读列 */
  --measure-wide: 64rem;   /* 1024px 目录容器 */
  --transition:  180ms cubic-bezier(0.2, 0.7, 0.3, 1);
}

/* --- Reset -------------------------------------------------------------- */

*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }

html {
  -webkit-text-size-adjust: 100%;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  hanging-punctuation: first last;
}

img, svg { display: block; max-width: 100%; }

body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--step-0);
  line-height: 1.75;
  font-feature-settings: "kern" 1, "liga" 1, "calt" 1;
  min-height: 100vh;
  background-image:
    radial-gradient(ellipse 60% 50% at 12% 18%,
      rgba(154, 42, 42, 0.025) 0%, transparent 55%),
    radial-gradient(ellipse 70% 60% at 88% 82%,
      rgba(107, 93, 77, 0.045) 0%, transparent 60%);
  background-attachment: fixed;
}

::selection {
  background: var(--vermilion);
  color: var(--paper);
}

:focus-visible {
  outline: 2px solid var(--vermilion);
  outline-offset: 3px;
  border-radius: 2px;
}

/* --- 容器 --------------------------------------------------------------- */

.shell {
  max-width: var(--measure-wide);
  margin: 0 auto;
  padding: 0 var(--gutter);
  position: relative;
}

/* --- 报头 --------------------------------------------------------------- */

.masthead {
  padding: 3.25rem 0 1.75rem;
  margin-bottom: 3.5rem;
  border-bottom: 1px solid var(--ash);
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 1rem;
}

.wordmark {
  font-family: var(--font-display);
  font-size: var(--step-2);
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--ink);
  text-decoration: none;
  display: inline-flex;
  align-items: baseline;
  gap: 0.15em;
}
.wordmark .mark {
  color: var(--vermilion);
  font-size: 1.15em;
  line-height: 1;
}
.wordmark:hover .mark,
.wordmark:focus-visible .mark { color: var(--vermilion-deep); }

.season {
  font-family: var(--font-mono);
  font-size: var(--step--2);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ash);
}

/* --- 目录首页 ----------------------------------------------------------- */

.catalog-header {
  text-align: center;
  margin-bottom: 3.5rem;
}

.catalog-title {
  font-family: var(--font-display);
  font-size: clamp(var(--step-4), 8vw, var(--step-5));
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.05;
  margin-bottom: 0.75rem;
  /* 字间距：把"目 录"撑开 */
}

.catalog-subtitle {
  font-family: var(--font-display);
  font-style: italic;
  font-size: var(--step-2);
  color: var(--ink-soft);
  letter-spacing: 0.01em;
}

.catalog-blurb {
  max-width: 34rem;
  margin: 2.25rem auto 0;
  font-size: var(--step-1);
  line-height: 1.85;
  color: var(--ink-soft);
  text-align: justify;
  text-justify: inter-character;
}

.catalog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 22rem), 1fr));
  gap: 1.75rem;
  margin-bottom: 4rem;
}

/* --- 目录卡片 ----------------------------------------------------------- */

.card {
  position: relative;
  background: var(--paper);
  border: 1px solid var(--paper-edge);
  padding: 1.85rem 1.5rem 1.35rem;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  transition: transform var(--transition),
              box-shadow var(--transition),
              border-color var(--transition);
  box-shadow:
    0 1px 0 var(--paper-shadow),
    2px 2px 0 var(--paper-shadow);
}

.card:hover,
.card:focus-visible {
  transform: translate(-1px, -1px);
  box-shadow:
    0 1px 0 var(--paper-shadow),
    3px 3px 0 var(--paper-shadow);
  border-color: var(--ash);
  outline: none;
}

.card-class {
  font-family: var(--font-mono);
  font-size: var(--step--2);
  letter-spacing: 0.12em;
  color: var(--ash);
  position: absolute;
  top: 0.85rem;
  right: 1.1rem;
}

.card-title {
  font-family: var(--font-display);
  font-size: var(--step-3);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.01em;
  padding-right: 3rem;
  color: var(--ink);
}

.card:hover .card-title,
.card:focus-visible .card-title {
  color: var(--vermilion);
}

.card-summary {
  font-size: var(--step-0);
  line-height: 1.7;
  color: var(--ink-soft);
  flex: 1;
}

.card-meta {
  display: flex;
  gap: 0.6rem;
  font-family: var(--font-mono);
  font-size: var(--step--2);
  letter-spacing: 0.06em;
  color: var(--ash);
  padding-top: 0.85rem;
  border-top: 1px dashed var(--paper-edge);
  flex-wrap: wrap;
}
.card-meta .sep { opacity: 0.45; }
.card-meta .tag { color: var(--moss); }

/* --- 文章页 ----------------------------------------------------------- */

.article-shell {
  padding-top: 1.5rem;
}

.article-header {
  position: relative;
  margin-bottom: 4rem;
  padding-top: 4.5rem;
}

/* 借书戳 */
.stamp {
  position: absolute;
  top: -0.5rem;
  right: 0;
  width: 5.5rem;
  height: 5.5rem;
  color: var(--vermilion);
  transform: rotate(-9deg);
  opacity: 0.88;
  filter: contrast(1.08);
}
.stamp circle { fill: none; stroke: currentColor; }
.stamp text {
  fill: currentColor;
  font-family: var(--font-mono);
  font-weight: 700;
}

.article-class {
  font-family: var(--font-mono);
  font-size: var(--step--2);
  letter-spacing: 0.14em;
  color: var(--ash);
  margin-bottom: 1.25rem;
}

.article-title {
  font-family: var(--font-display);
  font-size: clamp(var(--step-4), 5.5vw, var(--step-5));
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin-bottom: 1.25rem;
  max-width: 18ch;
}

.article-byline {
  font-family: var(--font-display);
  font-style: italic;
  font-size: var(--step-2);
  color: var(--ink-soft);
  margin-bottom: 1.25rem;
  letter-spacing: 0.005em;
}

.article-meta {
  font-family: var(--font-mono);
  font-size: var(--step--2);
  letter-spacing: 0.1em;
  color: var(--ash);
  display: flex;
  gap: 0.85rem;
  flex-wrap: wrap;
}
.article-meta .sep { opacity: 0.45; }

/* --- 正文（含眉批） ----------------------------------------------------- */

.article-body {
  margin-bottom: 3rem;
}

.article-body p {
  font-size: var(--step-1);
  line-height: 1.95;
  margin: 0 auto 1.6rem;
  max-width: var(--measure);
  text-align: justify;
  text-justify: inter-character;
}

/* 段首大字 */
.article-body .lede::first-letter {
  font-family: var(--font-display);
  font-size: 3.6em;
  float: left;
  line-height: 0.92;
  margin: 0.08em 0.12em -0.05em 0;
  color: var(--vermilion);
  font-weight: 700;
}

.article-body h2 {
  font-family: var(--font-display);
  font-size: var(--step-3);
  font-weight: 600;
  letter-spacing: -0.005em;
  margin: 3.25rem auto 1.4rem;
  max-width: var(--measure);
  position: relative;
  padding-left: 1.75rem;
  line-height: 1.35;
}
.article-body h2::before {
  content: "§";
  position: absolute;
  left: -0.1rem;
  color: var(--vermilion);
  font-weight: 400;
  font-style: italic;
}

.article-body blockquote {
  margin: 2.25rem auto;
  max-width: var(--measure);
  padding: 0.25rem 0 0.25rem 1.5rem;
  border-left: 2px solid var(--vermilion);
  font-family: var(--font-display);
  font-style: italic;
  font-size: var(--step-2);
  line-height: 1.55;
  color: var(--ink-soft);
}

/* 眉批 */
.marginalia {
  font-family: var(--font-display);
  font-style: italic;
  font-size: var(--step--1);
  line-height: 1.55;
  color: var(--moss);
  padding: 0.85rem 1rem 0.85rem 1.1rem;
  border-left: 2px solid var(--moss-soft);
  background: rgba(92, 107, 71, 0.045);
  max-width: var(--measure);
  margin: 0 auto 1.6rem;
}
.marginalia .marker {
  font-family: var(--font-mono);
  font-style: normal;
  font-size: var(--step--2);
  letter-spacing: 0.16em;
  color: var(--moss);
  display: block;
  margin-bottom: 0.4rem;
  opacity: 0.8;
}

/* 脚注标记 */
.article-body sup {
  font-family: var(--font-mono);
  font-size: 0.7em;
  color: var(--vermilion);
  margin-left: 0.15em;
  font-weight: 700;
  line-height: 0;
}
.article-body sup a {
  color: inherit;
  text-decoration: none;
}
.article-body sup a:hover,
.article-body sup a:focus-visible {
  color: var(--vermilion-deep);
}

/* 脚注区 */
.footnotes {
  max-width: var(--measure);
  margin: 4rem auto 0;
  padding-top: 2rem;
  border-top: 1px solid var(--paper-edge);
  font-size: var(--step--1);
  color: var(--ink-soft);
  line-height: 1.7;
}
.footnotes ol {
  padding-left: 0;
  list-style: none;
  counter-reset: fn;
}
.footnotes li {
  counter-increment: fn;
  margin-bottom: 0.85rem;
  padding-left: 2.25rem;
  position: relative;
}
.footnotes li::before {
  content: counter(fn);
  position: absolute;
  left: 0;
  font-family: var(--font-mono);
  font-size: var(--step--2);
  color: var(--vermilion);
  font-weight: 700;
}
.footnotes li a {
  color: var(--ash);
  text-decoration: none;
  margin-left: 0.4em;
  font-family: var(--font-mono);
}
.footnotes li a:hover,
.footnotes li a:focus-visible {
  color: var(--vermilion);
}

/* 文章导航 */
.article-nav {
  max-width: var(--measure);
  margin: 3rem auto 0;
  padding-top: 2rem;
  border-top: 1px solid var(--paper-edge);
  display: flex;
  justify-content: space-between;
  gap: 2rem;
  font-family: var(--font-mono);
  font-size: var(--step--1);
}
.article-nav a {
  color: var(--ink);
  text-decoration: none;
  transition: color var(--transition);
  max-width: 45%;
  font-family: var(--font-display);
  font-style: italic;
}
.article-nav a:hover,
.article-nav a:focus-visible {
  color: var(--vermilion);
}
.article-nav .label {
  display: block;
  font-family: var(--font-mono);
  font-style: normal;
  font-size: var(--step--2);
  letter-spacing: 0.14em;
  margin-bottom: 0.35rem;
  color: var(--ash);
  text-transform: uppercase;
}
.article-nav .prev { text-align: left; }
.article-nav .next { text-align: right; margin-left: auto; }

/* --- 版权页 ------------------------------------------------------------- */

.colophon {
  margin-top: 5rem;
  padding: 2.25rem 0;
  border-top: 1px solid var(--ash);
  font-family: var(--font-mono);
  font-size: var(--step--2);
  letter-spacing: 0.1em;
  color: var(--ash);
  text-align: center;
}
.colophon .dot {
  display: inline-block;
  margin: 0 0.75em;
  color: var(--vermilion);
}

/* --- 宽屏眉批布局 ------------------------------------------------------- */

@media (min-width: 1280px) {
  .article-body.has-marginalia {
    display: grid;
    grid-template-columns:
      1fr
      minmax(0, var(--measure))
      minmax(0, 16rem)
      1fr;
    column-gap: 2.5rem;
    row-gap: 0;
    align-items: start;
  }
  .article-body.has-marginalia > p,
  .article-body.has-marginalia > h2,
  .article-body.has-marginalia > blockquote,
  .article-body.has-marginalia > .footnotes {
    grid-column: 2;
    max-width: none;
    margin-left: 0;
    margin-right: 0;
  }
  .article-body.has-marginalia > .marginalia {
    grid-column: 3;
    margin: 0;
    padding: 0.5rem 0 0.5rem 1.25rem;
    border-left: 1px solid var(--moss-soft);
    background: transparent;
    max-width: none;
    align-self: start;
  }
  /* 让 .footnotes 横跨 */
  .article-body.has-marginalia > .footnotes {
    grid-column: 2 / 4;
  }
}

/* --- 响应式 ------------------------------------------------------------- */

@media (max-width: 720px) {
  .masthead {
    padding: 2rem 0 1.25rem;
    margin-bottom: 2.5rem;
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
  .catalog-header { margin-bottom: 2.5rem; }
  .catalog-blurb { font-size: var(--step-0); }
  .catalog-grid { gap: 1.25rem; }
  .card { padding: 1.5rem 1.25rem 1.15rem; }
  .card-title { font-size: var(--step-2); }

  .article-header { padding-top: 3.5rem; margin-bottom: 2.5rem; }
  .stamp { width: 3.75rem; height: 3.75rem; top: 0; }
  .article-body p { line-height: 1.85; }
  .article-body h2 { padding-left: 1.5rem; font-size: var(--step-2); }
  .article-nav { flex-direction: column; gap: 1.25rem; }
  .article-nav a { max-width: 100%; }
  .article-nav .next { text-align: left; }
}

/* --- 可访问性 ----------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}

/* 键盘可见焦点 */
a:focus:not(:focus-visible) { outline: none; }