:root {
  --bg: #f4efe7;
  --paper: var(--surface, #fbfaf6);
  --surface-muted: #eee7dc;
  --ink: var(--text, #1f1b16);
  --muted: #625a50;
  --line: var(--border, #d8ccbd);
  --separator: #ded2c3;
  --accent: #c96442;
  --accent-strong: #8f3f2a;
  --accent-soft: #f1dfd4;
  --warm-soft: #fff8e5;
  --reader-radius: var(--radius-lg, 18px);
  --reader-shadow: var(--card-shadow, none);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background: var(--bg);
  font-family: Inter, -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.78;
}

a { color: inherit; }

.toc-toggle,
.toc-backdrop {
  display: none;
}

.layout {
  display: grid;
  grid-template-columns: 224px minmax(0, 1fr);
  gap: 24px;
  width: min(1220px, calc(100% - 40px));
  margin: 112px auto 72px;
  align-items: start;
}

aside {
  position: sticky;
  top: 96px;
  max-height: calc(100svh - 120px);
  display: flex;
  flex-direction: column;
  min-height: 0;
  padding: 18px 14px;
  overflow: hidden;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--reader-radius);
  box-shadow: none;
}

aside h1 {
  margin: 0 0 4px;
  color: var(--ink);
  font-size: 15px;
  line-height: 1.35;
  font-weight: 700;
}

aside p {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.55;
}

.site-links,
nav {
  display: grid;
  gap: 2px;
  min-width: 0;
  overflow: auto;
  padding: 0;
  scrollbar-width: thin;
}

aside nav {
  margin-top: 14px;
  min-height: 0;
  padding-right: 2px;
}

nav ul {
  display: grid;
  gap: 2px;
  list-style: none;
  margin: 0;
  padding: 0;
}

nav ul ul {
  display: grid;
  gap: 1px;
  margin: 3px 0 5px 8px;
  padding-left: 8px;
  border-left: 1px solid var(--separator);
}

nav li {
  margin: 0;
  min-width: 0;
}

.site-links {
  margin: 0 0 18px;
  padding: 0 0 16px;
  border-bottom: 1px solid var(--line);
}

.site-links a,
nav a {
  display: block;
  padding: 6px 8px;
  color: var(--muted);
  border: 1px solid transparent;
  border-radius: 8px;
  background: transparent;
  text-decoration: none;
  font-size: 12.5px;
  line-height: 1.45;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

nav ul ul a {
  font-size: 11.5px;
  padding: 5px 7px;
}

.site-links a:hover,
nav a:hover {
  color: var(--accent-strong);
  background: var(--accent-soft);
  border-color: color-mix(in srgb, var(--accent) 24%, var(--line));
}

main {
  width: 100%;
  max-width: none;
  min-width: 0;
  padding: 44px clamp(26px, 3.4vw, 68px) 84px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--reader-radius);
  box-shadow: var(--reader-shadow);
}

.hero,
section {
  scroll-margin-top: 116px;
  padding: 0 0 44px;
  margin: 0 0 44px;
  border-bottom: 1px solid var(--line);
}

.hero { padding-top: 2px; }

.kicker {
  margin: 0 0 6px;
  color: var(--accent);
  font-size: .75em;
  font-weight: 700;
  letter-spacing: .08em;
}

h1,
h2,
h3,
h4 {
  line-height: 1.32;
}

h1 {
  margin: 0 0 12px;
  color: var(--ink);
  font-size: 2.1em;
}

h2 {
  margin: 0 0 15px;
  color: var(--ink);
  font-size: 1.68em;
}

section h2 { font-size: 1.52em; }

h3 {
  margin: 26px 0 10px;
  color: var(--accent-strong);
  font-size: 1.12em;
}

h4 {
  margin: 20px 0 8px;
  font-size: 1em;
}

p { margin: 9px 0; }

ul,
ol {
  padding-left: 1.35em;
}

li { margin: 5px 0; }

code {
  padding: 1px 4px;
  color: var(--ink);
  background: var(--surface-muted);
  border-radius: 3px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: .9em;
}

pre {
  overflow-x: auto;
  padding: 12px 14px;
  background: var(--surface-muted);
  border: 1px solid var(--line);
  border-radius: 8px;
}

pre code {
  padding: 0;
  background: transparent;
  border-radius: 0;
}

mjx-container {
  max-width: 100%;
}

blockquote {
  margin: 16px 0;
  padding: 8px 0 8px 15px;
  color: var(--muted);
  border-left: 3px solid var(--accent);
}

table {
  display: block;
  width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
  margin: 17px 0;
  font-size: .88em;
}

th,
td {
  border: 1px solid var(--line);
  padding: 7px 9px;
  vertical-align: top;
}

th {
  background: var(--accent-soft);
  color: var(--ink);
  font-weight: 700;
}

.math-display,
.display-math {
  overflow-x: auto;
  max-width: 1440px;
  margin: 14px 0;
  padding: 9px 12px;
  background: var(--surface-muted);
  border-left: 2px solid var(--accent);
}

.notes-index {
  max-width: 980px;
}

.note-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 18px;
  align-items: baseline;
  padding: 15px 0;
  color: var(--ink);
  border-top: 1px solid var(--line);
  text-decoration: none;
}

.note-row:first-child {
  border-top: 0;
}

.note-row strong {
  display: block;
  font-size: 1.03em;
}

.note-row span {
  color: var(--muted);
  font-size: .82em;
}

.note-row em {
  color: var(--accent);
  font-style: normal;
  font-size: .85em;
  font-weight: 700;
}

.note-row:hover strong,
.note-row:hover em {
  color: var(--accent);
}

figure {
  margin: 20px 0;
}

figure img,
p > img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow: none;
}

figcaption {
  margin-top: 8px;
  color: var(--muted);
  font-size: .82em;
  line-height: 1.5;
  text-align: center;
}

@media (max-width: 860px) {
  body.toc-open {
    overflow: hidden;
  }

  .toc-toggle {
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 42;
    width: 36px;
    height: 36px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    color: var(--ink);
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 50%;
    box-shadow: none;
    cursor: pointer;
  }

  .toc-toggle:hover {
    background: var(--surface-muted);
  }

  body.toc-open .toc-toggle {
    border-color: color-mix(in srgb, var(--accent) 30%, var(--line));
    color: var(--accent-strong);
  }

  .toc-backdrop {
    position: fixed;
    inset: 0;
    z-index: 35;
    display: block;
    background: rgba(31, 27, 22, 0.22);
  }

  .toc-backdrop[hidden] {
    display: none;
  }

  .layout {
    display: block;
    width: calc(100% - 28px);
    margin: 88px auto 36px;
  }

  aside {
    position: fixed;
    top: 76px;
    left: 14px;
    bottom: 14px;
    z-index: 45;
    width: min(310px, calc(100vw - 28px));
    max-height: none;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    margin: 0;
    padding: 16px 14px;
    transform: translateX(calc(-100% - 18px));
    transition: transform 0.2s ease;
  }

  body.toc-open aside {
    transform: translateX(0);
  }

  aside nav {
    margin-top: 14px;
    min-height: 0;
    overflow: auto;
    padding-right: 2px;
  }

  .site-links,
  nav {
    display: grid;
    gap: 2px;
    overflow: auto;
    padding-bottom: 0;
  }

  nav ul {
    display: grid;
    gap: 2px;
    width: auto;
  }

  nav ul ul {
    display: grid;
  }

  nav li {
    flex: initial;
  }

  .site-links a,
  nav a {
    max-width: none;
    border: 1px solid transparent;
    border-radius: 8px;
    background: transparent;
  }

  main {
    padding: 28px 18px 56px;
  }

  p,
  li {
    overflow-wrap: anywhere;
  }

  .math.inline,
  mjx-container[jax="SVG"] {
    display: inline-block;
    max-width: 100%;
    overflow-x: auto;
    overflow-y: hidden;
    vertical-align: middle;
  }

  .hero,
  section {
    padding-bottom: 34px;
    margin-bottom: 34px;
  }

  .note-row {
    grid-template-columns: 1fr;
    gap: 4px;
  }
}

@media print {
  body { background: #fff; }

  .layout { display: block; }

  aside { display: none; }

  main { padding: 0; }

  .hero,
  section {
    break-inside: avoid;
  }
}