/* ------------------------------------------------------------------ *
 * 基础层：字体、颜色变量、正文排版。网页与 PDF 共用。
 * ------------------------------------------------------------------ */

@font-face {
  font-family: "Noto Serif SC";
  src: url("../fonts/noto-serif-sc-400.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Noto Serif SC";
  src: url("../fonts/noto-serif-sc-700.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

:root {
  --serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
          "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  --paper: #faf7f1;
  --paper-raised: #fffdf8;
  --ink: #24211c;
  --ink-soft: #5c554b;
  --ink-faint: #8c8477;
  --accent: #9c3b24;
  --accent-soft: #bf6147;
  --rule: #e3dacb;
  --rule-strong: #cdc2b0;
  --quote-bg: #f2ebdf;
  --code-bg: #f0e9dd;
  --shadow: 0 1px 2px rgba(70, 52, 30, .05), 0 12px 32px rgba(70, 52, 30, .06);

  --measure: 40rem;
  --radius: 8px;
}

html[data-theme="dark"] {
  --paper: #15130f;
  --paper-raised: #1c1915;
  --ink: #e9e2d6;
  --ink-soft: #b3aa9b;
  --ink-faint: #8a8173;
  --accent: #d9805f;
  --accent-soft: #e39a7d;
  --rule: #322c24;
  --rule-strong: #463e33;
  --quote-bg: #1e1a15;
  --code-bg: #24201a;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 16px 40px rgba(0, 0, 0, .35);
}

@media (prefers-color-scheme: dark) {
  html[data-theme="auto"] {
    --paper: #15130f;
    --paper-raised: #1c1915;
    --ink: #e9e2d6;
    --ink-soft: #b3aa9b;
    --ink-faint: #8a8173;
    --accent: #d9805f;
    --accent-soft: #e39a7d;
    --rule: #322c24;
    --rule-strong: #463e33;
    --quote-bg: #1e1a15;
    --code-bg: #24201a;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 16px 40px rgba(0, 0, 0, .35);
  }
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.9;
  font-feature-settings: "palt" 0;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: color-mix(in srgb, var(--accent) 22%, transparent); }

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-soft); }

img, svg, video { max-width: 100%; height: auto; }

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  z-index: 999;
  padding: .6rem 1rem;
  background: var(--ink);
  color: var(--paper);
  border-radius: 0 0 var(--radius) 0;
}
.skip-link:focus { left: 0; }

/* ---------------- 正文排版 ---------------- */

.prose {
  max-width: var(--measure);
  font-size: 1.0625rem;
  line-height: 1.95;
  text-align: justify;
  text-justify: inter-ideograph;
  overflow-wrap: break-word;
}

.prose > :first-child { margin-top: 0; }

.prose p {
  margin: 0 0 1.15em;
}

.prose strong { font-weight: 700; }
.prose em { font-style: italic; }

.prose a {
  border-bottom: 1px solid color-mix(in srgb, var(--accent) 35%, transparent);
  padding-bottom: .5px;
}

.prose h2,
.prose h3,
.prose h4,
.prose h5,
.prose h6 {
  font-family: var(--serif);
  font-weight: 700;
  line-height: 1.5;
  scroll-margin-top: 4.6rem;
  text-align: left;
}

.prose h3 {
  font-size: 1.42rem;
  margin: 2.7em 0 .9em;
  padding-left: .72em;
  border-left: 4px solid var(--accent);
}

.prose h4 {
  font-size: 1.12rem;
  margin: 2.1em 0 .6em;
  color: var(--ink);
}

.prose h4::before {
  content: "";
  display: inline-block;
  width: .42em;
  height: .42em;
  margin-right: .55em;
  margin-bottom: .12em;
  background: var(--accent);
  transform: rotate(45deg);
}

.prose h5 {
  font-size: 1rem;
  margin: 1.7em 0 .45em;
  color: var(--ink-soft);
  letter-spacing: .02em;
}

.prose ul,
.prose ol {
  margin: 0 0 1.15em;
  padding-left: 1.6em;
}

.prose li { margin: .3em 0; }
.prose li > ul,
.prose li > ol { margin: .3em 0 .4em; }
.prose li p { margin-bottom: .4em; }

.prose blockquote {
  margin: 1.7em 0;
  padding: 1.05em 1.3em 1.05em 1.35em;
  background: var(--quote-bg);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--ink);
}

.prose blockquote p {
  margin: 0 0 .55em;
  text-indent: 0;
  font-size: 1.02em;
  letter-spacing: .01em;
}

.prose blockquote p:last-child { margin-bottom: 0; }
.prose blockquote em { color: var(--ink-soft); }

.prose hr {
  border: 0;
  height: 1.9em;
  margin: 1.4em 0;
  text-align: center;
  color: var(--accent-soft);
}
.prose hr::before {
  content: "❖";
  display: block;
  font-size: .82em;
  letter-spacing: .5em;
  opacity: .75;
}

.prose code {
  font-family: var(--mono);
  font-size: .88em;
  background: var(--code-bg);
  padding: .12em .38em;
  border-radius: 4px;
}

.prose pre {
  background: var(--code-bg);
  padding: 1em 1.15em;
  border-radius: var(--radius);
  overflow-x: auto;
  line-height: 1.65;
}
.prose pre code { background: none; padding: 0; }

/* 表格 */

.table-wrap {
  margin: 1.9em 0;
  overflow-x: auto;
  border-radius: var(--radius);
  -webkit-overflow-scrolling: touch;
}

.prose table {
  border-collapse: collapse;
  width: 100%;
  font-size: .88em;
  line-height: 1.7;
  text-align: left;
}

.prose th,
.prose td {
  padding: .62em .78em;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
}

.prose thead th {
  border-bottom: 2px solid var(--rule-strong);
  font-weight: 700;
  background: color-mix(in srgb, var(--quote-bg) 60%, transparent);
}

.prose tbody tr:last-child td { border-bottom: 0; }

/* 数学公式（pandoc --mathml 输出，无需 JS） */

math {
  font-family: "STIX Two Math", "Latin Modern Math", "Cambria Math", var(--serif);
  font-size: 1.02em;
}

math[display="block"],
.math.display,
div.math {
  display: block;
  margin: 1.3em 0;
  text-align: center;
  overflow-x: auto;
  overflow-y: hidden;
}

/* 脚注 */

.footnotes {
  margin-top: 3em;
  padding-top: 1.2em;
  border-top: 1px solid var(--rule);
  font-size: .9em;
  color: var(--ink-soft);
}
.footnotes ol { padding-left: 1.4em; }

/* 通用小元素 */

.kicker {
  margin: 0 0 .7em;
  font-family: var(--sans);
  font-size: .78rem;
  letter-spacing: .26em;
  color: var(--accent);
}

.dot { margin: 0 .5em; color: var(--ink-faint); }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}