/* =========================================================
   i4qi.com.cn — 爱思助手品牌站共享样式
   ========================================================= */

:root {
  --ink: #1c1c1a;
  --ink-soft: #4a4a46;
  --ink-muted: #77776f;
  --line: #d9d8d2;
  --line-strong: #b9b8b1;
  --paper: #f6f5f1;
  --paper-deep: #eeede7;
  --white: #fbfaf7;
  --brand: #b45309;
  --brand-ink: #7c3e08;
  --brand-soft: rgba(180, 83, 9, 0.12);
  --shadow: 0 1px 0 rgba(0, 0, 0, 0.04), 0 18px 40px rgba(0, 0, 0, 0.05);
  --radius: 14px;
  --radius-sm: 8px;
  --font-serif: "Songti SC", "Noto Serif SC", "STSong", "SimSun", Georgia, serif;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  --measure: 68ch;
  --container: 1180px;
  --gutter: clamp(1rem, 3vw, 2.5rem);
  --space-section: clamp(3rem, 6vw, 6rem);
  --fs-h1: clamp(2.25rem, 5.2vw, 4.3rem);
  --fs-h2: clamp(1.65rem, 3.2vw, 2.6rem);
  --fs-h3: clamp(1.15rem, 1.8vw, 1.4rem);
  --fs-body: clamp(1rem, 1.1vw, 1.08rem);
  --fs-small: clamp(0.82rem, 0.9vw, 0.9rem);
  --fs-lead: clamp(1.1rem, 1.4vw, 1.3rem);
}

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

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: 1.75;
  letter-spacing: 0.01em;
}

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

a {
  color: inherit;
  text-decoration-thickness: 0.06em;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--brand-ink);
}

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

::selection {
  background: var(--brand-soft);
  color: var(--ink);
}

section[id],
div[id] {
  scroll-margin-top: 5rem;
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.01em;
  margin: 0 0 0.6em;
  color: var(--ink);
  text-wrap: balance;
}

h1 {
  font-size: var(--fs-h1);
}

h2 {
  font-size: var(--fs-h2);
}

h3 {
  font-size: var(--fs-h3);
}

h4 {
  font-size: 1.05rem;
}

p {
  margin: 0 0 1em;
}

.lead {
  font-size: var(--fs-lead);
  color: var(--ink-soft);
  max-width: var(--measure);
}

.small {
  font-size: var(--fs-small);
}

.muted {
  color: var(--ink-muted);
}

.nowrap {
  white-space: nowrap;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.92em;
  background: var(--paper-deep);
  padding: 0.12em 0.3em;
  border-radius: 4px;
  overflow-wrap: anywhere;
}

.note {
  font-size: 0.85rem;
  color: var(--ink-muted);
}

.container {
  width: min(100% - var(--gutter) * 2, var(--container));
  margin-inline: auto;
}

.section {
  padding-block: var(--space-section);
  border-top: 1px solid var(--line);
}

.section-head {
  margin-bottom: clamp(1.5rem, 3vw, 2.5rem);
  max-width: 78ch;
}

.section-index {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--brand-ink);
  margin-bottom: 0.6rem;
}

.section-index::before {
  content: "";
  display: inline-block;
  width: 1.6rem;
  height: 1px;
  background: var(--brand);
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -3rem;
  z-index: 100;
  background: var(--ink);
  color: var(--white);
  padding: 0.5rem 0.8rem;
  border-radius: 4px;
  text-decoration: none;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 1rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid var(--line);
  background: rgba(246, 245, 241, 0.94);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 0.9rem;
  flex-wrap: wrap;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--ink);
}

.brand img {
  width: 40px;
  height: 40px;
  object-fit: contain;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-name {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.brand-sub {
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  color: var(--ink-muted);
  text-transform: uppercase;
}

.main-nav {
  display: flex;
  gap: 0.3rem;
  flex-wrap: wrap;
}

.main-nav a {
  padding: 0.45rem 0.8rem;
  border-radius: 999px;
  font-size: 0.92rem;
  text-decoration: none;
  color: var(--ink-soft);
  transition: background 0.2s ease, color 0.2s ease;
}

.main-nav a:hover {
  background: var(--paper-deep);
  color: var(--ink);
}

.main-nav a[aria-current="page"] {
  background: var(--ink);
  color: var(--white);
}

.main-nav a[aria-current="page"]:hover {
  background: var(--brand);
  color: var(--white);
}

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--paper-deep);
  padding-block: clamp(2rem, 4vw, 3.5rem);
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 0.8fr) minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: start;
}

.footer-brand img {
  width: 40px;
  height: 40px;
  object-fit: contain;
  margin-bottom: 0.6rem;
}

.footer-brand p {
  max-width: 48ch;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

.footer-title {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--ink-muted);
  text-transform: uppercase;
  margin-bottom: 0.8rem;
}

.footer-nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.4rem;
}

.footer-nav a {
  text-decoration: none;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

.footer-nav a:hover {
  color: var(--brand-ink);
}

.footer-nav a[aria-current="page"] {
  color: var(--ink);
  font-weight: 600;
}

.footer-meta p {
  margin-bottom: 0.5rem;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  border-top: 1px solid var(--line);
  margin-top: 2rem;
  padding-top: 1rem;
  font-size: 0.82rem;
  color: var(--ink-muted);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 2.9rem;
  padding: 0.65rem 1.2rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(0);
}

.btn-primary {
  background: var(--ink);
  color: var(--white);
  border-color: var(--ink);
}

.btn-primary:hover {
  background: var(--brand);
  border-color: var(--brand);
  color: var(--white);
}

.btn-secondary {
  background: transparent;
  color: var(--ink);
  border-color: var(--line-strong);
}

.btn-secondary:hover {
  border-color: var(--ink);
  background: var(--white);
  color: var(--ink);
}

.btn-accent {
  background: var(--brand);
  color: var(--white);
  border-color: var(--brand);
}

.btn-accent:hover {
  background: var(--brand-ink);
  border-color: var(--brand-ink);
  color: var(--white);
}

.btn-small {
  min-height: 2.2rem;
  padding: 0.35rem 0.75rem;
  font-size: 0.82rem;
}

.btn-row {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.hero {
  padding-block: clamp(2.5rem, 6vw, 5rem);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, var(--white), var(--paper));
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.95fr);
  gap: clamp(1.5rem, 4vw, 4rem);
  align-items: center;
}

.hero-copy {
  max-width: 66ch;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  color: var(--ink-muted);
  margin-bottom: 1rem;
}

.eyebrow .dot {
  display: inline-block;
  width: 0.45rem;
  height: 0.45rem;
  border-radius: 50%;
  background: var(--brand);
}

.hero-lead {
  font-size: var(--fs-lead);
  color: var(--ink-soft);
  max-width: 58ch;
}

.hero-actions {
  display: flex;
  gap: 0.7rem;
  flex-wrap: wrap;
  margin-block: 1.2rem 1rem;
}

.hero-note {
  font-size: 0.85rem;
  color: var(--ink-muted);
  max-width: 52ch;
}

.hero-visual {
  min-width: 0;
}

.svg-frame {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
}

.hero-svg {
  max-width: 680px;
  margin-inline: auto;
}

.svg-caption {
  font-size: 0.8rem;
  color: var(--ink-muted);
  margin-top: 0.6rem;
  text-align: center;
  max-width: 60ch;
  margin-inline: auto;
}

.intro-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(1rem, 2vw, 1.6rem);
}

.intro-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(1rem, 2vw, 1.4rem);
  box-shadow: var(--shadow);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.intro-card:hover {
  border-color: var(--line-strong);
  box-shadow: 0 10px 26px rgba(0, 0, 0, 0.07);
}

.intro-card h3 {
  margin-bottom: 0.4rem;
}

.intro-card p {
  font-size: 0.95rem;
  color: var(--ink-soft);
}

.feature-map {
  margin: 0 0 clamp(1.2rem, 2vw, 2rem);
}

.feature-map svg {
  max-width: 760px;
  margin-inline: auto;
}

.feature-map figcaption,
.quick-figure figcaption,
.safety-figure figcaption {
  font-size: 0.8rem;
  color: var(--ink-muted);
  text-align: center;
  margin-top: 0.4rem;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(1rem, 2vw, 1.4rem);
}

.feature-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(1rem, 2vw, 1.5rem);
  position: relative;
  box-shadow: var(--shadow);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
  border-color: var(--line-strong);
  box-shadow: 0 10px 26px rgba(0, 0, 0, 0.07);
}

.feature-no {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--brand-ink);
  margin-bottom: 0.5rem;
}

.feature-card h3 {
  margin-bottom: 0.3rem;
}

.feature-card p {
  font-size: 0.93rem;
  color: var(--ink-soft);
}

.scenario-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(1rem, 2vw, 1.6rem);
}

.scenario-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(1rem, 2vw, 1.6rem);
  box-shadow: var(--shadow);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.scenario-card:hover {
  border-color: var(--line-strong);
  box-shadow: 0 10px 26px rgba(0, 0, 0, 0.07);
}

.scenario-card h3 {
  margin-bottom: 0.5rem;
}

.scenario-card p {
  font-size: 0.95rem;
  color: var(--ink-soft);
}

.steps {
  list-style: none;
  padding: 0;
  margin: 0.9rem 0 0;
  display: grid;
  gap: 0.55rem;
  counter-reset: step;
}

.steps li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.7rem;
  align-items: start;
  font-size: 0.92rem;
  color: var(--ink-soft);
}

.steps li::before {
  counter-increment: step;
  content: counter(step);
  display: inline-flex;
  width: 1.5rem;
  height: 1.5rem;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--paper-deep);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 0.72rem;
  font-weight: 600;
  border: 1px solid var(--line);
}

.scenario-card .note {
  font-size: 0.85rem;
  color: var(--ink-muted);
  margin-top: 0.8rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--line);
}

.quick-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  gap: clamp(1.5rem, 3vw, 3rem);
  align-items: center;
}

.timeline {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.8rem;
  counter-reset: timeline;
}

.timeline li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.8rem;
  align-items: start;
  padding: 0.7rem 0.9rem;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  color: var(--ink-soft);
}

.timeline li::before {
  counter-increment: timeline;
  content: counter(timeline, decimal-leading-zero);
  font-family: var(--font-serif);
  font-size: 0.9rem;
  color: var(--brand-ink);
  border-right: 1px solid var(--line);
  padding-right: 0.8rem;
}

.timeline li strong {
  color: var(--ink);
  font-weight: 600;
}

.quick-figure {
  margin: 0;
}

.quick-svg {
  max-width: 760px;
  margin-inline: auto;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--white);
}

table {
  width: 100%;
  border-collapse: collapse;
  min-width: 620px;
}

table caption {
  caption-side: top;
  text-align: left;
  font-size: 0.85rem;
  color: var(--ink-muted);
  padding: 0.8rem 1rem 0;
}

thead th {
  text-align: left;
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--ink-muted);
  padding: 0.9rem 1rem;
  border-bottom: 1px solid var(--line-strong);
  background: var(--paper-deep);
}

tbody td {
  padding: 0.9rem 1rem;
  border-bottom: 1px solid var(--line);
  font-size: 0.9rem;
  color: var(--ink-soft);
  vertical-align: top;
}

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

tbody tr:hover {
  background: var(--paper);
}

tbody td strong {
  color: var(--ink);
}

.table-note {
  font-size: 0.85rem;
  color: var(--ink-muted);
  margin-top: 0.6rem;
}

.safety-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
  gap: clamp(1.5rem, 3vw, 3rem);
  align-items: start;
}

.safety-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.7rem;
}

.safety-list li {
  padding: 0.8rem 1rem;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  font-size: 0.93rem;
  color: var(--ink-soft);
}

.safety-list li strong {
  color: var(--ink);
}

.safety-figure {
  margin: 0;
}

.safety-svg {
  max-width: 360px;
  margin-inline: auto;
}

.version-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
  gap: clamp(1.5rem, 3vw, 3rem);
  align-items: start;
}

.version-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(1rem, 2vw, 1.6rem);
  box-shadow: var(--shadow);
}

.version-card dl {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.5rem 0.9rem;
  margin: 0.8rem 0 1rem;
}

.version-card dt {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: var(--ink-muted);
}

.version-card dd {
  margin: 0;
  font-size: 0.92rem;
  color: var(--ink);
}

.version-cta {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.version-note-card {
  background: var(--paper-deep);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(1rem, 2vw, 1.6rem);
}

.version-note-card h3 {
  margin-bottom: 0.4rem;
}

.version-note-card p {
  font-size: 0.92rem;
  color: var(--ink-soft);
}

.download-band {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  background: var(--ink);
  color: var(--white);
  border-radius: var(--radius);
  padding: clamp(1.2rem, 3vw, 2rem);
  margin-block: 1.5rem;
}

.download-band h3 {
  color: var(--white);
  margin-bottom: 0.3rem;
}

.download-band p {
  color: rgba(255, 255, 255, 0.72);
  font-size: 0.9rem;
  margin-bottom: 0;
}

.download-actions {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.download-band .btn-primary {
  background: var(--brand);
  border-color: var(--brand);
  color: var(--white);
}

.download-band .btn-primary:hover {
  background: var(--white);
  border-color: var(--white);
  color: var(--ink);
}

.download-band .btn-secondary {
  border-color: rgba(255, 255, 255, 0.4);
  color: var(--white);
}

.download-band .btn-secondary:hover {
  border-color: var(--white);
  background: rgba(255, 255, 255, 0.08);
  color: var(--white);
}

.download-steps {
  list-style: none;
  padding: 0;
  margin: 1rem 0;
  display: grid;
  gap: 0.5rem;
}

.download-steps li {
  display: flex;
  gap: 0.6rem;
  font-size: 0.93rem;
  color: var(--ink-soft);
}

.download-steps li::before {
  content: "→";
  color: var(--brand);
  font-weight: 600;
}

.faq-list {
  display: grid;
  gap: 0.6rem;
  margin-top: 1.2rem;
}

.faq-item {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.faq-item summary {
  cursor: pointer;
  padding: 0.9rem 1rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--ink);
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  transition: background 0.2s ease;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  font-family: var(--font-serif);
  font-size: 1.2rem;
  color: var(--brand);
  transition: transform 0.2s ease;
}

.faq-item[open] summary {
  background: var(--paper-deep);
  border-bottom: 1px solid var(--line);
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
}

.faq-item summary:hover {
  background: var(--paper);
}

.faq-item summary:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: -2px;
}

.faq-item p {
  margin: 0;
  padding: 0.1rem 1rem 1rem;
  font-size: 0.92rem;
  color: var(--ink-soft);
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(1rem, 2vw, 1.5rem);
}

.article-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(1rem, 2vw, 1.4rem);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  box-shadow: var(--shadow);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.article-card:hover {
  border-color: var(--line-strong);
  box-shadow: 0 10px 26px rgba(0, 0, 0, 0.07);
}

.article-card h3 {
  margin-bottom: 0;
}

.article-card p {
  font-size: 0.92rem;
  color: var(--ink-soft);
  margin-bottom: 0.2rem;
}

.article-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.6rem;
  margin-top: auto;
  padding-top: 0.6rem;
  border-top: 1px solid var(--line);
}

.article-card time {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  color: var(--ink-muted);
  letter-spacing: 0.02em;
}

.article-card .btn {
  margin-left: auto;
}

.related-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.5rem 1.5rem;
}

.related-list li {
  border-bottom: 1px solid var(--line);
  padding: 0.7rem 0;
}

.related-list a {
  font-family: var(--font-serif);
  font-weight: 600;
  text-decoration: none;
  color: var(--ink);
  display: inline-block;
}

.related-list a:hover {
  color: var(--brand-ink);
}

.related-list span {
  display: block;
  font-size: 0.85rem;
  color: var(--ink-muted);
  margin-top: 0.15rem;
}

.callout {
  border-left: 3px solid var(--brand);
  background: var(--paper-deep);
  padding: 0.8rem 1rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.9rem;
  color: var(--ink-soft);
  margin-block: 1rem;
}

.callout strong {
  color: var(--ink);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.2rem 0.55rem;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  font-family: var(--font-sans);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--ink-muted);
  background: var(--white);
}

.page-hero {
  padding-block: clamp(2.5rem, 5vw, 4.2rem);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, var(--white), var(--paper));
}

.page-hero h1 {
  margin-bottom: 0.4em;
}

.page-hero .lead {
  max-width: 64ch;
}

.prose {
  max-width: var(--measure);
}

.prose h2 {
  margin-top: 2.2rem;
}

.prose h3 {
  margin-top: 1.6rem;
}

.prose ul,
.prose ol {
  padding-left: 1.2rem;
}

.prose li {
  margin-bottom: 0.4rem;
  color: var(--ink-soft);
}

.content-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 0.4fr);
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: start;
}

.content-grid > .prose {
  min-width: 0;
}

.sidebar-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
  box-shadow: var(--shadow);
}

.sidebar-card h2,
.sidebar-card h3 {
  font-size: 1.1rem;
}

.sidebar-card p,
.sidebar-card li {
  font-size: 0.9rem;
  color: var(--ink-soft);
}

.sidebar-card ul {
  padding-left: 1rem;
}

.download-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: clamp(1.2rem, 3vw, 2rem);
  box-shadow: var(--shadow);
}

.download-card h2 {
  margin-bottom: 0.5rem;
}

.download-card .btn-row {
  margin-top: 1rem;
}

.meta-list {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.4rem 0.8rem;
  margin: 0;
}

.meta-list dt {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: var(--ink-muted);
}

.meta-list dd {
  margin: 0;
  font-size: 0.92rem;
  color: var(--ink);
}

.draw {
  stroke-dasharray: 1;
  stroke-dashoffset: 0;
  animation: draw 9s ease-in-out infinite alternate;
}

.sweep {
  transform-box: fill-box;
  transform-origin: center;
  animation: sweep 16s ease-in-out infinite alternate;
}

.pulse {
  transform-box: fill-box;
  transform-origin: center;
  animation: pulse 7s ease-in-out infinite;
}

@keyframes draw {
  0% {
    stroke-dashoffset: 1;
  }
  100% {
    stroke-dashoffset: 0;
  }
}

@keyframes sweep {
  0% {
    transform: translateX(-120%);
  }
  100% {
    transform: translateX(120%);
  }
}

@keyframes pulse {
  0%,
  100% {
    opacity: 0.55;
  }
  50% {
    opacity: 1;
  }
}

@media (max-width: 980px) {
  .hero-grid,
  .quick-grid,
  .safety-grid,
  .version-grid,
  .content-grid {
    grid-template-columns: 1fr;
  }

  .intro-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .footer-brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 700px) {
  .intro-grid,
  .feature-grid,
  .scenario-grid,
  .article-grid,
  .related-list {
    grid-template-columns: 1fr;
  }

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

  .header-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .main-nav {
    width: 100%;
  }

  .hero-actions .btn,
  .download-actions .btn,
  .version-cta .btn {
    width: 100%;
  }

  .download-band {
    flex-direction: column;
    align-items: flex-start;
  }

  .download-actions {
    width: 100%;
  }

  .table-wrap {
    border-radius: var(--radius-sm);
  }

  table {
    min-width: 560px;
  }

  .section {
    padding-block: clamp(2.2rem, 7vw, 3.5rem);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .draw,
  .sweep,
  .pulse {
    animation: none;
  }

  .btn,
  .skip-link,
  .faq-item summary,
  .faq-item summary::after,
  .main-nav a,
  .intro-card,
  .feature-card,
  .scenario-card,
  .article-card {
    transition: none;
  }
}