:root {
  color-scheme: light;
  --ink: #3c3c43;
  --ink-strong: #252630;
  --muted: #6c6f85;
  --subtle: #8c8fa1;
  --night: #eff1f5;
  --night-soft: #e6e9ef;
  --surface: rgba(255, 255, 255, 0.72);
  --surface-strong: rgba(255, 255, 255, 0.96);
  --line: #ccd0da;
  --line-soft: #dce0e8;
  --line-strong: rgba(64, 160, 43, 0.55);
  --flutter: #1e66f5;
  --flutter-deep: #1752c7;
  --mint: #40a02b;
  --warning: #fe640b;
  --sidebar-width: 21rem;
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-width: 20rem;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(44rem 32rem at 12% -8%, rgba(64, 160, 43, 0.11), transparent 72%),
    radial-gradient(40rem 30rem at 92% 0%, rgba(30, 102, 245, 0.09), transparent 70%),
    var(--night);
  font-size: 1rem;
  line-height: 1.75;
  overflow-wrap: anywhere;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
}

button,
a,
summary {
  -webkit-tap-highlight-color: transparent;
}

:focus-visible {
  outline: 0.1875rem solid var(--mint);
  outline-offset: 0.25rem;
  border-radius: 0.25rem;
}

.topbar {
  width: min(76rem, calc(100% - 3rem));
  min-height: 5.5rem;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.875rem;
  color: var(--ink);
  text-decoration: none;
}

.site-mark {
  width: 2.5rem;
  height: 2.5rem;
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  color: #ffffff;
  background: linear-gradient(145deg, var(--mint), var(--flutter));
  border-radius: 0.75rem 0.25rem 0.75rem 0.25rem;
  box-shadow: 0 0.75rem 2.5rem rgba(30, 102, 245, 0.16);
  transform: rotate(-4deg);
}

.site-mark span {
  font: 800 1.125rem/1 ui-monospace, SFMono-Regular, Menlo, monospace;
  transform: rotate(4deg);
}

.brand-copy {
  display: grid;
  line-height: 1.2;
}

.brand-copy strong {
  font-size: 0.9375rem;
  letter-spacing: 0.02em;
}

.brand-copy small {
  margin-top: 0.3rem;
  color: var(--subtle);
  font-size: 0.75rem;
}

.text-link {
  color: var(--muted);
  font-size: 0.875rem;
  text-decoration: none;
}

.text-link:hover {
  color: var(--flutter);
}

.course-intro {
  width: min(76rem, calc(100% - 3rem));
  min-height: 39rem;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(18rem, 0.6fr);
  align-items: center;
  gap: clamp(3rem, 8vw, 8rem);
  padding: 5rem 0;
}

.eyebrow {
  margin: 0 0 1.25rem;
  color: var(--mint);
  font: 700 0.75rem/1.2 ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: 0.16em;
}

.intro-copy h1 {
  max-width: 48rem;
  margin: 0;
  font-size: clamp(2.75rem, 6vw, 5.7rem);
  line-height: 1.04;
  letter-spacing: -0.055em;
  color: var(--ink-strong);
}

.intro-copy h1 span {
  color: transparent;
  background: linear-gradient(90deg, var(--flutter), var(--mint));
  background-clip: text;
  -webkit-background-clip: text;
}

.intro-text {
  max-width: 42rem;
  margin: 2rem 0 0;
  color: var(--muted);
  font-size: 1.0625rem;
}

.intro-actions {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-top: 2.25rem;
}

.primary-action,
.secondary-action {
  min-height: 3rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9375rem;
  font-weight: 700;
  text-decoration: none;
}

.primary-action {
  gap: 1.25rem;
  padding: 0.75rem 1.25rem;
  color: #ffffff;
  background: linear-gradient(120deg, var(--flutter), var(--mint));
  border-radius: 0.75rem;
  box-shadow: 0 1rem 3rem rgba(30, 102, 245, 0.16);
}

.secondary-action {
  color: var(--muted);
}

.secondary-action:hover {
  color: var(--ink);
}

.course-status {
  position: relative;
  min-height: 24rem;
  padding: 2rem;
  overflow: hidden;
  color: #cdd6f4;
  background: linear-gradient(#181825 0 2.65rem, #11111b 2.65rem);
  border: 1px solid #313244;
  border-radius: 1.5rem;
  box-shadow: 0 2rem 5rem -2.5rem rgba(0, 0, 0, 0.78), 0 0 3.5rem -2.5rem rgba(64, 160, 43, 0.6);
}

.course-status::before {
  content: "";
  position: absolute;
  top: 1rem;
  left: 1.1rem;
  width: 0.64rem;
  height: 0.64rem;
  border-radius: 50%;
  background: #f38ba8;
  box-shadow: 1.05rem 0 #f9e2af, 2.1rem 0 #a6e3a1;
}

.status-orbit {
  position: absolute;
  top: -5rem;
  right: -5rem;
  width: 15rem;
  height: 15rem;
  border: 1px solid rgba(84, 196, 255, 0.25);
  border-radius: 50%;
}

.status-orbit::before,
.status-orbit::after {
  content: "";
  position: absolute;
  border: 1px solid rgba(99, 245, 208, 0.14);
  border-radius: 50%;
}

.status-orbit::before { inset: 2rem; }
.status-orbit::after { inset: 4rem; }

.status-orbit span {
  position: absolute;
  top: 50%;
  left: -0.25rem;
  width: 0.5rem;
  height: 0.5rem;
  background: var(--mint);
  border-radius: 50%;
  box-shadow: 0 0 1.25rem var(--mint);
}

.course-status > p {
  margin: 2rem 0 0;
  color: #a6adc8;
  font-size: 0.8125rem;
}

.course-status > strong {
  position: relative;
  display: block;
  margin-top: 1.5rem;
  font-size: 4.8rem;
  line-height: 1;
  letter-spacing: -0.06em;
  color: #f4f5fb;
}

.course-status > strong span {
  color: #6c7086;
  font-size: 1.5rem;
  letter-spacing: 0;
}

.course-status > small {
  color: #a6e3a1;
  font-size: 0.8125rem;
}

.course-status dl {
  margin: 3.5rem 0 0;
  border-top: 1px solid #313244;
}

.course-status dl div {
  display: flex;
  justify-content: space-between;
  padding: 0.7rem 0;
  border-bottom: 1px solid #313244;
}

.course-status dt,
.course-status dd {
  margin: 0;
  font-size: 0.8125rem;
}

.course-status dt { color: #6c7086; }
.course-status dd { color: #cdd6f4; }

.course-map {
  width: min(76rem, calc(100% - 3rem));
  margin: 0 auto;
  padding: 5rem 0 7rem;
  border-top: 1px solid var(--line);
}

.map-heading {
  max-width: 42rem;
  margin-bottom: 4rem;
}

.map-heading h2 {
  margin: 0;
  font-size: clamp(2rem, 4vw, 3.5rem);
  line-height: 1.1;
  letter-spacing: -0.04em;
  color: var(--ink-strong);
}

.map-heading > p:last-child {
  margin: 1rem 0 0;
  color: var(--muted);
}

.course-section {
  display: grid;
  grid-template-columns: 13rem minmax(0, 1fr);
  gap: 2rem;
  padding: 2.75rem 0;
  border-top: 1px solid var(--line);
}

.section-heading {
  position: sticky;
  top: 2rem;
  align-self: start;
}

.section-heading > span,
.section-heading > small {
  color: var(--subtle);
  font: 0.75rem/1.2 ui-monospace, SFMono-Regular, Menlo, monospace;
}

.section-heading h2 {
  margin: 0.5rem 0 1.5rem;
  font-size: 1.125rem;
  line-height: 1.35;
  color: var(--ink-strong);
}

.lesson-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.lesson-card {
  min-width: 0;
  min-height: 14rem;
  display: flex;
  flex-direction: column;
  padding: 1.5rem;
  text-decoration: none;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 1rem;
  transition: border-color 160ms ease, transform 160ms ease, background 160ms ease;
}

.lesson-card:hover {
  background: var(--surface-strong);
  border-color: var(--line-strong);
  box-shadow: 0 0.9rem 2rem -1.2rem rgba(64, 160, 43, 0.36);
  transform: translateY(-0.2rem);
}

.lesson-index {
  color: var(--flutter);
  font: 700 0.6875rem/1.2 ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: 0.12em;
}

.lesson-card h3 {
  margin: 1rem 0 0.75rem;
  font-size: 1.125rem;
  line-height: 1.45;
  color: var(--ink-strong);
}

.lesson-card p {
  display: -webkit-box;
  margin: 0;
  overflow: hidden;
  color: var(--muted);
  font-size: 0.875rem;
  line-height: 1.65;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 3;
}

.lesson-action {
  margin-top: auto;
  padding-top: 1.5rem;
  color: var(--muted);
  font-size: 0.8125rem;
}

.lesson-card:hover .lesson-action { color: var(--mint); }

.site-footer {
  width: min(76rem, calc(100% - 3rem));
  min-height: 6rem;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  color: var(--subtle);
  font-size: 0.8125rem;
  border-top: 1px solid var(--line);
}

.lesson-sidebar {
  position: fixed;
  inset: 0 auto 0 0;
  z-index: 2;
  width: var(--sidebar-width);
  padding: 1.5rem;
  overflow-y: auto;
  background: rgba(239, 241, 245, 0.94);
  border-right: 1px solid var(--line);
  backdrop-filter: blur(1rem);
}

.sidebar-progress {
  margin: 2rem 0 1rem;
}

.sidebar-progress span {
  color: var(--subtle);
  font-size: 0.75rem;
}

.sidebar-progress i {
  height: 0.125rem;
  display: block;
  margin-top: 0.65rem;
  overflow: hidden;
  background: var(--line);
}

.sidebar-progress i::after {
  content: "";
  width: var(--progress);
  height: 100%;
  display: block;
  background: linear-gradient(90deg, var(--flutter), var(--mint));
}

.lesson-nav {
  display: grid;
  gap: 0.25rem;
}

.lesson-link {
  min-width: 0;
  min-height: 3rem;
  display: grid;
  grid-template-columns: 2rem minmax(0, 1fr);
  align-items: center;
  gap: 0.5rem;
  padding: 0.55rem 0.65rem;
  color: var(--muted);
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: 0.6rem;
}

.lesson-link span {
  color: var(--subtle);
  font: 0.6875rem/1 ui-monospace, SFMono-Regular, Menlo, monospace;
}

.lesson-link strong {
  overflow: hidden;
  font-size: 0.78rem;
  font-weight: 500;
  line-height: 1.35;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.lesson-link:hover {
  color: var(--mint);
  background: rgba(64, 160, 43, 0.06);
}

.lesson-link.is-current {
  color: var(--mint);
  background: rgba(64, 160, 43, 0.09);
  border-color: rgba(64, 160, 43, 0.18);
}

.lesson-link.is-current span { color: var(--mint); }

.lesson-main {
  min-width: 0;
  margin-left: var(--sidebar-width);
  display: grid;
  grid-template-columns: minmax(0, 48rem) minmax(10rem, 13rem);
  justify-content: center;
  align-items: start;
  gap: clamp(1.5rem, 3vw, 3rem);
  padding: 2rem clamp(1.5rem, 3vw, 3rem) 0;
}

.mobile-header,
.mobile-course-nav {
  display: none;
}

.lesson-article {
  min-width: 0;
  width: 100%;
  margin: 0;
  padding: 2.75rem 2rem 4rem;
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid var(--line-soft);
  border-radius: 0.75rem;
  box-shadow: 0 1.5rem 4rem -3rem rgba(37, 38, 48, 0.28);
}

.standalone-main .lesson-article {
  width: min(48rem, calc(100% - 3rem));
  margin: 0 auto;
  padding: 2.75rem 2rem 4rem;
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid var(--line-soft);
  border-radius: 0.75rem;
}

.article-header {
  margin-bottom: 4rem;
  padding-bottom: 2.25rem;
  border-bottom: 1px solid var(--line-soft);
}

.article-header > p {
  margin: 0 0 1.25rem;
  color: var(--mint);
  font: 700 0.75rem/1.2 ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: 0.14em;
}

.article-header h1 {
  margin: 0;
  font-size: clamp(2rem, 4vw, 2.5rem);
  font-weight: 750;
  line-height: 1.22;
  letter-spacing: -0.035em;
  color: var(--ink-strong);
}

.article-header > div {
  display: flex;
  gap: 1.5rem;
  margin-top: 1.75rem;
  color: var(--subtle);
  font-size: 0.75rem;
}

.article-body {
  min-width: 0;
  color: #4c4f69;
  font-size: 1.0625rem;
  line-height: 1.85;
}

.article-body h2,
.article-body h3,
.article-body h4 {
  color: var(--ink-strong);
  line-height: 1.35;
  scroll-margin-top: 2rem;
}

.article-body h2 {
  margin: 3.5rem 0 1.15rem;
  font-size: 1.5rem;
  letter-spacing: -0.025em;
}

.article-body h2::before {
  content: "●";
  margin-right: 0.65em;
  color: var(--mint);
  font-size: 0.58em;
  vertical-align: 0.22em;
}

.article-body h3 {
  margin: 2.75rem 0 1rem;
  font-size: 1.2rem;
}

.article-body h3::before {
  content: "⌞";
  margin-right: 0.45em;
  color: var(--subtle);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

.article-body h4 {
  margin: 2rem 0 0.75rem;
  font-size: 1rem;
}

.article-body p,
.article-body ul,
.article-body ol {
  margin: 1rem 0;
}

.article-body li + li {
  margin-top: 0.45rem;
}

.article-body a {
  color: var(--flutter);
  text-decoration-color: rgba(84, 196, 255, 0.35);
  text-underline-offset: 0.2em;
}

.article-body a:hover {
  color: var(--mint);
  text-decoration-color: currentColor;
}

.article-body code {
  padding: 0.15em 0.4em;
  color: #fe640b;
  background: rgba(230, 233, 239, 0.78);
  border: 1px solid var(--line-soft);
  border-radius: 0.35rem;
  font: 0.9em/1.5 ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

.article-body pre {
  position: relative;
  margin: 1.5rem 0;
  padding: 3.7rem 1.4rem 1.35rem;
  overflow-x: auto;
  color: #cdd6f4;
  background: linear-gradient(#181825 0 2.65rem, #11111b 2.65rem);
  border: 1px solid #313244;
  border-radius: 0.9rem;
  -webkit-overflow-scrolling: touch;
}

.article-body pre::before {
  content: "";
  position: absolute;
  top: 1rem;
  left: 1.1rem;
  width: 0.64rem;
  height: 0.64rem;
  border-radius: 50%;
  background: #f38ba8;
  box-shadow: 1.05rem 0 #f9e2af, 2.1rem 0 #a6e3a1;
}

.article-body pre code {
  padding: 0;
  color: inherit;
  background: transparent;
  border: 0;
  font-size: 0.875rem;
  line-height: 1.7;
}

.article-body blockquote {
  margin: 1.5rem 0;
  padding: 0.9rem 1.25rem;
  color: #4c4f69;
  background: linear-gradient(100deg, rgba(64, 160, 43, 0.09), transparent 78%);
  border-left: 0.2rem solid var(--mint);
}

.article-body blockquote p { margin: 0; }

.article-body table {
  width: 100%;
  display: block;
  margin: 1.5rem 0;
  overflow-x: auto;
  border-spacing: 0;
  border-collapse: collapse;
  -webkit-overflow-scrolling: touch;
}

.article-body th,
.article-body td {
  min-width: 9rem;
  padding: 0.75rem 0.9rem;
  text-align: left;
  vertical-align: top;
  border: 1px solid var(--line);
}

.article-body th {
  color: var(--mint);
  background: rgba(64, 160, 43, 0.09);
  font-size: 0.875rem;
}

.article-body td {
  font-size: 0.9rem;
}

.article-body img {
  max-width: 100%;
  height: auto;
  display: block;
  margin: 1.75rem auto;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: 0.9rem;
  box-shadow: 0 1.5rem 4rem rgba(0, 0, 0, 0.2);
}

.article-body hr {
  margin: 3rem 0;
  border: 0;
  border-top: 1px solid var(--line);
}

.article-body input[type="checkbox"] {
  width: 1rem;
  height: 1rem;
  margin-right: 0.5rem;
  accent-color: var(--flutter-deep);
}

.chapter-pagination {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--line);
}

.chapter-step {
  min-width: 0;
  min-height: 7rem;
  display: flex;
  flex-direction: column;
  padding: 1.2rem;
  text-decoration: none;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 0.8rem;
}

.chapter-step:hover { border-color: var(--line-strong); }
.chapter-step--next { text-align: right; }
.chapter-step span { color: var(--subtle); font-size: 0.75rem; }
.chapter-step strong { margin-top: auto; font-size: 0.9rem; line-height: 1.5; }

.article-footer {
  grid-column: 1 / -1;
  min-height: 5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0 2rem;
  color: var(--subtle);
  font-size: 0.75rem;
  border-top: 1px solid var(--line);
}

.article-footer a {
  color: var(--muted);
  text-decoration: none;
}

.standalone-main .lesson-article {
  padding-top: 4rem;
}

.article-outline {
  position: sticky;
  top: 1.5rem;
  max-height: calc(100vh - 3rem);
  overflow-y: auto;
  color: var(--muted);
  scrollbar-width: thin;
}

.article-outline > p {
  margin: 0 0 1rem;
  color: var(--subtle);
  font: 650 0.7rem/1.4 ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: 0.12em;
}

.article-outline > p::before {
  content: "> ";
  color: var(--mint);
}

.article-outline ol,
.mobile-toc ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

.article-outline li {
  position: relative;
  margin-bottom: 0.55rem;
  padding-left: 1.05rem;
}

.article-outline li::before {
  content: "●";
  position: absolute;
  top: 0.28rem;
  left: 0;
  color: #9ca0b0;
  font-size: 0.48rem;
}

.article-outline .outline-subitem {
  padding-left: 1.55rem;
}

.article-outline .outline-subitem::before {
  content: "⌞";
  top: -0.05rem;
  font: 0.78rem/1.5 ui-monospace, SFMono-Regular, Menlo, monospace;
}

.article-outline a {
  display: block;
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.55;
  text-decoration: none;
}

.article-outline a:hover {
  color: var(--mint);
}

.mobile-toc {
  display: none;
  margin: 2rem 0;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  background: rgba(230, 233, 239, 0.66);
}

.mobile-toc summary {
  padding: 1rem 1.25rem;
  cursor: pointer;
  color: var(--ink-strong);
  font: 650 0.85rem/1.5 ui-monospace, SFMono-Regular, Menlo, monospace;
}

.mobile-toc ol {
  padding: 0 1.25rem 1.2rem 2rem;
}

.mobile-toc li + li { margin-top: 0.4rem; }
.mobile-toc .outline-subitem { margin-left: 1rem; }
.mobile-toc a { color: var(--muted); font-size: 0.82rem; text-decoration: none; }
.mobile-toc a:hover { color: var(--mint); }

@media (max-width: 1180px) {
  .lesson-main {
    grid-template-columns: minmax(0, 48rem);
  }

  .article-outline {
    display: none;
  }

  .mobile-toc {
    display: block;
  }
}

@media (max-width: 980px) {
  .course-intro {
    grid-template-columns: minmax(0, 1fr);
    gap: 3rem;
  }

  .course-status {
    min-height: 18rem;
  }

  .course-status dl {
    margin-top: 2.5rem;
  }

  .lesson-sidebar {
    display: none;
  }

  .lesson-main {
    margin-left: 0;
    display: block;
    padding: 0;
  }

  .mobile-header {
    min-height: 4rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 0 1.25rem;
    color: var(--subtle);
    font: 0.75rem/1 ui-monospace, SFMono-Regular, Menlo, monospace;
    border-bottom: 1px solid var(--line);
  }

  .mobile-brand {
    color: var(--ink);
    font-family: inherit;
    text-decoration: none;
  }

  .mobile-course-nav {
    display: block;
    width: min(52rem, calc(100% - 2rem));
    margin: 1rem auto 0;
    background: rgba(255, 255, 255, 0.72);
    border: 1px solid var(--line);
    border-radius: 0.75rem;
  }

  .mobile-course-nav summary {
    min-height: 3rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
    color: var(--muted);
    cursor: pointer;
    list-style: none;
  }

  .mobile-course-nav summary::-webkit-details-marker { display: none; }
  .mobile-course-nav summary span { color: var(--subtle); font-size: 0.75rem; }
  .mobile-course-nav nav { max-height: 24rem; padding: 0.5rem; overflow-y: auto; border-top: 1px solid var(--line); }
}

@media (max-width: 720px) {
  .topbar,
  .course-intro,
  .course-map,
  .site-footer {
    width: min(100% - 2rem, 76rem);
  }

  .topbar {
    min-height: 4.5rem;
  }

  .brand-copy small {
    display: none;
  }

  .topbar .text-link {
    font-size: 0.75rem;
  }

  .course-intro {
    min-height: auto;
    padding: 4rem 0;
  }

  .intro-copy h1 {
    font-size: clamp(2.45rem, 12vw, 4rem);
  }

  .intro-actions {
    align-items: stretch;
    flex-direction: column;
    gap: 0.75rem;
  }

  .primary-action,
  .secondary-action {
    width: 100%;
  }

  .course-status {
    min-height: 18rem;
    padding: 1.5rem;
  }

  .course-status > strong {
    font-size: 4rem;
  }

  .course-map {
    padding: 4rem 0;
  }

  .course-section {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .section-heading {
    position: static;
  }

  .section-heading h2 {
    margin-bottom: 0.4rem;
  }

  .lesson-grid {
    grid-template-columns: 1fr;
  }

  .lesson-card {
    min-height: 12.5rem;
  }

  .lesson-article,
  .standalone-main .lesson-article {
    width: min(100% - 2rem, 52rem);
    margin: 0 auto;
    padding: 3rem 0 4rem;
    background: transparent;
    border: 0;
    box-shadow: none;
  }

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

  .article-header h1 {
    font-size: clamp(1.9rem, 9vw, 2.3rem);
  }

  .article-header > div {
    align-items: flex-start;
    flex-direction: column;
    gap: 0.35rem;
  }

  .article-body {
    font-size: 1rem;
    line-height: 1.8;
  }

  .article-body h2 {
    margin-top: 3.25rem;
  }

  .article-body pre {
    margin-right: -0.25rem;
    margin-left: -0.25rem;
    padding: 3.5rem 1rem 1rem;
    border-radius: 0.7rem;
  }

  .article-body th,
  .article-body td {
    min-width: 8rem;
    padding: 0.65rem 0.75rem;
  }

  .chapter-pagination {
    grid-template-columns: 1fr;
  }

  .chapter-step--next { text-align: left; }
  .article-footer { align-items: flex-start; flex-direction: column; justify-content: center; }
}

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