:root {
  --bg: #f5f5f7;
  --surface: rgba(255, 255, 255, 0.72);
  --surface-2: #ffffff;
  --surface-strong: #ffffff;
  --text: #1d1d1f;
  --muted: #86868b;
  --primary: #0071e3;
  --primary-soft: rgba(0, 113, 227, 0.08);
  --accent: #2997ff;
  --border: rgba(0, 0, 0, 0.08);
  --border-solid: #e5e5ea;
  --code-bg: #f5f5f7;
  --code-text: #1d1d1f;
  --shadow: 0 4px 14px rgba(0, 0, 0, 0.04), 0 14px 32px rgba(0, 0, 0, 0.04);
  --shadow-soft: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-glow: 0 0 0 4px rgba(0, 113, 227, 0.15);
  --radius: 20px;
  --radius-sm: 10px;
  --content-width: 72ch;
  --sidebar-width: 260px;
  --header-height: 52px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  color: var(--text);
  line-height: 1.6;
  font-weight: 400;
  letter-spacing: -0.015em;
  background: var(--bg);
}

body.dark {
  --bg: #000000;
  --surface: rgba(29, 29, 31, 0.72);
  --surface-2: #1d1d1f;
  --surface-strong: #1d1d1f;
  --text: #f5f5f7;
  --muted: #86868b;
  --primary: #2997ff;
  --primary-soft: rgba(41, 151, 255, 0.12);
  --accent: #64d2ff;
  --border: rgba(255, 255, 255, 0.15);
  --border-solid: #333336;
  --code-bg: #1d1d1f;
  --code-text: #f5f5f7;
  --shadow: 0 4px 14px rgba(0, 0, 0, 0.4), 0 14px 32px rgba(0, 0, 0, 0.4);
  --shadow-soft: 0 2px 8px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 0 4px rgba(41, 151, 255, 0.25);
  background: var(--bg);
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

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

code,
pre code {
  font-family: "Cascadia Code", Consolas, monospace;
}

.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1200;
  width: 0%;
  height: 4px;
  background: linear-gradient(90deg, var(--accent), var(--primary));
}

.site-topbar {
  position: sticky;
  top: 0;
  z-index: 1100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  min-height: 52px;
  width: 100%;
  margin: 0;
  padding: 0 max(1.5rem, calc((100% - 1050px) / 2));
  background: var(--surface);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border);
  border-radius: 0;
  box-shadow: none;
  transition: all 0.3s ease;
}

body.dark .site-topbar {
  box-shadow: none;
}

.site-brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  min-width: 0;
}

.site-brand-badge {
  width: 32px;
  height: 32px;
  min-width: 32px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  font-weight: 800;
  color: #ffffff;
  background: var(--primary);
  box-shadow: none;
  flex-shrink: 0;
  font-size: 0.95rem;
}

.site-brand-text {
  min-width: 0;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.site-brand-text strong {
  display: block;
  max-width: min(42vw, 20ch);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 0.98rem;
  line-height: 1.2;
}

.site-brand-text span {
  display: block;
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.2;
}

.site-topbar-actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.site-btn {
  border: 1px solid var(--border);
  background: var(--surface-strong);
  color: var(--text);
  border-radius: 999px;
  padding: 0.68rem 1rem;
  cursor: pointer;
  font: inherit;
  transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease;
}

.site-btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-soft);
  text-decoration: none;
}

.site-btn:focus-visible,
.copy-code:focus-visible,
.toc a:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--accent) 65%, transparent);
  outline-offset: 2px;
}

.site-layout {
  width: min(1120px, calc(100% - 2rem));
  margin: 2rem auto 4rem;
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  gap: 1.25rem;
  align-items: start;
}

.site-sidebar {
  position: sticky;
  top: calc(var(--header-height) + 1rem);
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.site-sidebar-panel,
.sidebar-card,
.book-article {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
}

body.dark .site-sidebar-panel,
body.dark .sidebar-card,
body.dark .book-article {
  border: 1px solid var(--border-solid);
}

.site-sidebar-panel {
  padding: 1.25rem;
  max-height: calc(100vh - var(--header-height) - 3rem);
  overflow: auto;
  scrollbar-width: thin;
}

nav#TOC {
  margin: 0;
}

nav#TOC::before {
  content: "目錄";
  display: block;
  margin-bottom: 0.9rem;
  font-size: 1rem;
  font-weight: 800;
  letter-spacing: 0.04em;
}

nav#TOC > ul,
.toc {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.55rem;
}

nav#TOC li,
.toc li {
  margin: 0;
}

nav#TOC a,
.toc a {
  display: block;
  padding: 0.55rem 0.8rem;
  border-radius: 8px;
  color: var(--text);
  text-decoration: none;
  transition: all 0.2s ease;
  border: none;
  background: transparent;
  font-weight: 500;
  font-size: 0.95rem;
}

nav#TOC a::before,
.toc a::before {
  display: none;
}

nav#TOC a:hover,
.toc a:hover {
  background: var(--primary-soft);
  color: var(--primary);
}

nav#TOC a.active,
.toc a.active {
  background: var(--primary);
  color: #ffffff;
  font-weight: 600;
}

nav#TOC > ul > li:first-child,
nav#TOC ul ul {
  display: none;
}

.sidebar-card {
  padding: 1rem;
}

.sidebar-card strong {
  display: block;
  margin-bottom: 0.35rem;
}

.sidebar-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.site-main {
  min-width: 0;
  display: grid;
  gap: 1.25rem;
}

.site-hero {
  position: relative;
  overflow: hidden;
  width: 100%;
  margin: 0;
  min-height: auto;
  padding: 1.25rem 2rem;
  border-radius: var(--radius) !important;
  transform: translateZ(0);
  background: linear-gradient(135deg, #e0f2fe 0%, #bae6fd 100%);
  color: #0c4a6e;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  gap: 0.5rem;
  box-shadow: var(--shadow-soft);
}

body.dark .site-hero {
  background: linear-gradient(135deg, rgba(41, 151, 255, 0.15) 0%, rgba(0, 113, 227, 0.25) 100%);
  color: #f0f9ff;
  border: 1px solid var(--border-solid);
}

.site-hero::before {
  display: none;
}

.site-hero::after {
  display: none;
}

.site-hero > * {
  position: relative;
  z-index: 1;
}

#title-block-header {
  margin: 0;
}

.site-hero-kicker {
  margin: 0;
  color: inherit;
  opacity: 0.85;
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.06em;
}

h1.title {
  margin: 0;
  font-size: clamp(1.6rem, 1.4rem + 1vw, 2.2rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
  max-width: 30ch;
  text-wrap: balance;
  color: inherit;
}

p.author {
  display: inline-block;
  margin: 1rem 0 0;
  padding: 0.52rem 1rem;
  border-radius: 999px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  font-weight: 600;
}

.site-hero-lead {
  max-width: 34rem;
  margin: 0.2rem auto 0;
  color: inherit;
  opacity: 0.9;
  font-size: 0.95rem;
  line-height: 1.5;
  font-weight: 400;
}

.book-article {
  padding: clamp(1.4rem, 1.05rem + 1.1vw, 2.25rem);
}

.book-article > * {
  max-width: var(--content-width);
}

.book-article > h1,
.book-article > h2,
.book-article > h3,
.book-article > h4,
.book-article > h5,
.book-article > h6,
.book-article > p,
.book-article > ul,
.book-article > ol,
.book-article > blockquote,
.book-article > pre,
.book-article > div.sourceCode,
.book-article > figure,
.book-article > table,
.book-article > hr,
.book-article > div {
  margin-left: auto;
  margin-right: auto;
}

.book-article > h1:first-child {
  display: none;
}

h1:not(.title),
h2,
h3,
h4,
h5,
h6 {
  color: var(--text);
  scroll-margin-top: calc(var(--header-height) + 1.5rem);
}

h1:not(.title) {
  margin-top: 2.2rem;
  padding: 1rem 1.15rem;
  border-radius: 20px;
  background: linear-gradient(180deg, rgba(232, 243, 255, 0.88) 0%, rgba(255, 255, 255, 0.98) 100%);
  border: 1px solid #d9ebff;
  box-shadow: var(--shadow-soft);
  font-size: clamp(1.5rem, 1.2rem + 0.9vw, 2.05rem);
}

body.dark h1:not(.title) {
  background: linear-gradient(180deg, rgba(30, 41, 59, 0.9) 0%, rgba(15, 23, 42, 0.96) 100%);
  border-color: #334155;
}

h2 {
  margin-top: 1.9rem;
  padding-bottom: 0.45rem;
  border-bottom: 2px solid color-mix(in srgb, var(--primary) 20%, #bfdbfe);
  font-size: clamp(1.35rem, 1.18rem + 0.6vw, 1.95rem);
}

h3 {
  margin-top: 1.5rem;
  font-size: clamp(1.08rem, 1rem + 0.38vw, 1.34rem);
}

p,
li {
  color: var(--text);
}

p {
  font-size: 1.03rem;
}

ul,
ol {
  padding-left: 1.4rem;
}

li + li {
  margin-top: 0.35rem;
}

blockquote {
  margin: 1.2rem auto;
  padding: 0.95rem 1rem;
  border-left: 4px solid #60a5fa;
  background: color-mix(in srgb, var(--surface-2) 88%, #f3fbff);
  border-radius: 12px;
}

pre,
div.sourceCode {
  position: relative;
  margin: 1.2rem auto;
}

pre {
  background: var(--code-bg);
  color: var(--code-text);
  padding: 1rem 1.1rem;
  border-radius: 16px;
  overflow-x: auto;
  border: 1px solid #d9e9f8;
  box-shadow:
    0 10px 24px rgba(37, 99, 235, 0.06),
    inset 0 0 0 1px rgba(255, 255, 255, 0.55);
}

div.sourceCode {
  background: transparent;
  border: none;
  box-shadow: none;
  padding: 0;
  overflow: visible;
}

div.sourceCode > pre {
  margin: 0;
}

pre code,
div.sourceCode code {
  color: inherit;
}

code span.kw,
code span.cf,
code span.op {
  color: #1d4ed8;
}

code span.fu,
code span.bu {
  color: #0f766e;
}

code span.st,
code span.ch,
code span.sc {
  color: #0f766e;
}

code span.dv,
code span.bn,
code span.fl {
  color: #047857;
}

code span.co,
code span.do,
code span.an,
code span.cv,
code span.in,
code span.wa {
  color: #6b7280;
}

code span.va,
code span.ot,
code span.at {
  color: #334155;
}

.copy-code {
  position: absolute;
  top: 0.8rem;
  right: 0.8rem;
  border: 1px solid #cfe0f3;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.9);
  color: #1f3b57;
  padding: 0.4rem 0.72rem;
  font: inherit;
  font-size: 0.88rem;
  cursor: pointer;
}

body.dark pre,
body.dark div.sourceCode {
  border-color: #24334c;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.04);
}

body.dark .copy-code {
  border-color: rgba(255, 255, 255, 0.18);
  background: rgba(15, 23, 42, 0.72);
  color: #e2e8f0;
}

body.dark code span.kw,
body.dark code span.cf,
body.dark code span.op {
  color: #8bb8ff;
}

body.dark code span.fu,
body.dark code span.bu,
body.dark code span.st,
body.dark code span.ch,
body.dark code span.sc {
  color: #5eead4;
}

body.dark code span.dv,
body.dark code span.bn,
body.dark code span.fl {
  color: #86efac;
}

body.dark code span.co,
body.dark code span.do,
body.dark code span.an,
body.dark code span.cv,
body.dark code span.in,
body.dark code span.wa {
  color: #94a3b8;
}

body.dark code span.va,
body.dark code span.ot,
body.dark code span.at {
  color: #dbeafe;
}

p code,
li code {
  padding: 0.14rem 0.42rem;
  border-radius: 6px;
  background: var(--primary-soft);
  color: var(--primary);
}

hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2rem auto;
}

img,
svg {
  max-width: 100%;
  border-radius: 18px;
}

figure {
  margin: 1.6rem auto 2rem;
}

figure img {
  box-shadow: var(--shadow);
}

figcaption {
  margin-top: 0.75rem;
  text-align: center;
  color: var(--muted);
  font-size: 0.95rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  overflow: hidden;
  border-radius: 16px;
  box-shadow: var(--shadow-soft);
}

th,
td {
  padding: 0.8rem 0.9rem;
  border: 1px solid var(--border);
  text-align: left;
}

th {
  background: #f6fbff;
}

body.sidebar-open {
  overflow: hidden;
}

@media (max-width: 980px) {
  .site-layout {
    width: min(100%, calc(100% - 1rem));
    grid-template-columns: minmax(0, 1fr);
  }

  .site-topbar {
    width: min(100%, calc(100% - 1rem));
  }

  .site-sidebar {
    position: fixed;
    top: calc(var(--header-height) + 0.7rem);
    left: 0.5rem;
    right: 0.5rem;
    z-index: 1050;
    transform: translateY(-14px);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.2s ease, opacity 0.2s ease;
  }

  body.sidebar-open .site-sidebar {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .site-sidebar-panel {
    max-height: min(68vh, 520px);
  }
}

@media (min-width: 981px) {
  .site-btn[data-role="menu"] {
    display: none;
  }
}

@media (max-width: 720px) {
  .site-topbar {
    padding: 0 0.75rem;
    width: min(100%, calc(100% - 0.6rem));
  }

  .site-brand-text span {
    display: none;
  }

  .site-layout {
    margin-top: 0.8rem;
    width: min(100%, calc(100% - 0.6rem));
  }

  .site-hero,
  .book-article {
    border-radius: 20px;
  }

  .site-hero {
    min-height: 220px;
  }

  h1.title {
    max-width: 100%;
    text-wrap: pretty;
  }

  .book-article {
    padding: 1.15rem 0.95rem;
  }

  pre,
  div.sourceCode {
    padding-top: 3.1rem;
  }

  .copy-code {
    top: 0.7rem;
    right: 0.7rem;
  }
}