:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --line: #e5e7eb;
  --line-strong: #d1d5db;
  --accent: #111827;
  --accent-soft: #f3f4f6;
  --ok: #059669;
  --warn: #d97706;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(17, 24, 39, 0.04), 0 8px 24px rgba(17, 24, 39, 0.04);
  --font: "Segoe UI Variable Text", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --mono: "Cascadia Mono", "Consolas", "SFMono-Regular", monospace;
  --max: 1080px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  font-size: 16px;
}

a {
  color: inherit;
  text-decoration: none;
}

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

.container {
  width: min(var(--max), calc(100% - 40px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(247, 248, 250, 0.88);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 64px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.logo-mark {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  background: var(--accent);
  color: #fff;
  font-size: 12px;
  font-family: var(--mono);
}

.logo-text span {
  color: var(--muted);
  font-weight: 500;
}

.nav-links {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}

.nav-links a {
  padding: 8px 12px;
  border-radius: 8px;
  color: var(--muted);
  font-size: 14px;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
  background: var(--surface);
}

.lang-switch {
  display: inline-flex;
  border: 1px solid var(--line);
  border-radius: 999px;
  overflow: hidden;
  background: var(--surface);
}

.lang-switch button {
  border: 0;
  background: transparent;
  color: var(--muted);
  padding: 6px 12px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
}

.lang-switch button.active {
  background: var(--accent);
  color: #fff;
}

.hero {
  padding: 72px 0 48px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 40px;
  align-items: center;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 18px;
}

.tag {
  font-size: 12px;
  color: var(--muted);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 5px 10px;
}

.hero h1 {
  margin: 0 0 14px;
  font-size: clamp(32px, 5vw, 48px);
  line-height: 1.15;
  letter-spacing: -0.03em;
  font-weight: 750;
}

.hero h1 em {
  font-style: normal;
  border-bottom: 3px solid var(--text);
}

.hero-lead {
  margin: 0 0 28px;
  color: var(--muted);
  font-size: 17px;
  max-width: 520px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 28px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
  transition: 0.15s ease;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  opacity: 0.9;
}

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

.btn-secondary:hover,
.btn-ghost:hover {
  background: var(--accent-soft);
}

.btn-ghost {
  background: transparent;
  border-color: var(--line);
  color: var(--text);
  min-height: 36px;
  padding: 0 12px;
  font-size: 13px;
}

.trust-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.trust-item {
  padding: 14px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.trust-item strong {
  display: block;
  font-size: 18px;
  margin-bottom: 2px;
}

.trust-item span,
.trust-item {
  color: var(--muted);
  font-size: 13px;
}

.trust-item strong {
  color: var(--text);
}

.hero-visual {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.hero-visual img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.hero-caption {
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 12px;
  color: var(--muted);
}

.section {
  padding: 64px 0;
}

.section-alt {
  background: var(--surface);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.section-head {
  margin-bottom: 28px;
  max-width: 640px;
}

.eyebrow {
  display: inline-block;
  margin-bottom: 8px;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 600;
}

.section-head h2,
.page-hero h1 {
  margin: 0 0 10px;
  font-size: clamp(24px, 3vw, 32px);
  letter-spacing: -0.02em;
  line-height: 1.25;
}

.section-head p,
.page-hero p {
  margin: 0;
  color: var(--muted);
}

.page-hero {
  padding: 48px 0 16px;
}

.grid-5,
.grid-3,
.compat-grid,
.steps,
.capability-list {
  display: grid;
  gap: 14px;
}

.grid-5 {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.grid-3,
.steps {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.compat-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.platform-card,
.feature-card,
.reco-card,
.scene-card,
.compat-item,
.step-card,
.faq-item,
.how-copy,
.doc-block {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.section-alt .platform-card,
.section-alt .feature-card,
.section-alt .reco-card,
.section-alt .scene-card,
.section-alt .compat-item,
.section-alt .step-card,
.section-alt .faq-item,
.section-alt .how-copy,
.section-alt .doc-block,
.section-alt .how-visual {
  background: var(--bg);
}

.platform-card,
.feature-card,
.reco-card,
.scene-card,
.compat-item,
.step-card,
.doc-block {
  padding: 18px;
}

.platform-card h3,
.feature-card h3,
.reco-card h3,
.scene-card h3,
.compat-item h3,
.step-card h3,
.doc-block h3 {
  margin: 0 0 8px;
  font-size: 17px;
  letter-spacing: -0.01em;
}

.platform-card p,
.feature-card p,
.scene-card p,
.compat-item p,
.step-card p,
.doc-block p,
.doc-block li {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.meta-line {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  margin: 8px 0;
  font-size: 12px;
  color: var(--muted);
}

.status {
  color: var(--ok);
  font-weight: 600;
}

.status.warn {
  color: var(--warn);
}

.feature-card .icon {
  width: 36px;
  height: 36px;
  margin-bottom: 12px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  background: var(--accent-soft);
  color: var(--text);
  font-family: var(--mono);
  font-size: 12px;
}

.how-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.how-copy {
  padding: 22px;
}

.how-copy ol {
  margin: 0;
  padding-left: 18px;
  color: var(--muted);
}

.how-copy li {
  margin-bottom: 12px;
}

.how-copy li strong {
  color: var(--text);
}

.how-visual {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--surface);
  position: relative;
  min-height: 280px;
}

.how-visual img {
  width: 100%;
  height: 100%;
  min-height: 280px;
  object-fit: cover;
}

.code-panel {
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 12px;
  padding: 12px 14px;
  border-radius: 10px;
  background: rgba(17, 24, 39, 0.9);
  color: #e5e7eb;
  font-family: var(--mono);
  font-size: 12px;
  line-height: 1.55;
}

.capability-list {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
}

.capability-list li {
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--muted);
  font-size: 14px;
}

.section-alt .capability-list li {
  background: var(--bg);
}

.capability-list strong {
  display: block;
  color: var(--text);
  margin-bottom: 4px;
}

.reco-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.reco-meta {
  display: grid;
  gap: 6px;
  color: var(--muted);
  font-size: 14px;
}

.reco-meta strong {
  color: var(--text);
  font-weight: 600;
}

.reco-card .btn {
  margin-top: auto;
  width: 100%;
}

.step-num {
  display: inline-block;
  margin-bottom: 10px;
  font-size: 12px;
  font-family: var(--mono);
  color: var(--muted);
  letter-spacing: 0.04em;
}

.error-box {
  margin-top: 16px;
  padding: 16px 18px;
  border-radius: var(--radius);
  border: 1px solid #fde68a;
  background: #fffbeb;
  color: #92400e;
  font-size: 14px;
}

.error-box a {
  text-decoration: underline;
}

.faq-list {
  display: grid;
  gap: 10px;
}

.faq-item details {
  padding: 16px 18px;
}

.faq-item summary {
  cursor: pointer;
  font-weight: 650;
  list-style: none;
}

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

.faq-item summary::after {
  content: "+";
  float: right;
  color: var(--muted);
  font-weight: 400;
}

.faq-item details[open] summary::after {
  content: "−";
}

.faq-item p {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.cta {
  padding: 24px 0 72px;
}

.cta-panel {
  padding: 40px 28px;
  border-radius: 16px;
  border: 1px solid var(--line);
  background: var(--surface);
  text-align: center;
  box-shadow: var(--shadow);
}

.cta-panel h2 {
  margin: 0 0 8px;
  font-size: clamp(24px, 3vw, 32px);
  letter-spacing: -0.02em;
}

.cta-panel p {
  margin: 0 0 20px;
  color: var(--muted);
}

.cta-actions {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--surface);
  padding: 48px 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr repeat(4, 1fr);
  gap: 24px;
  margin-bottom: 24px;
}

.site-footer h3 {
  margin: 0 0 12px;
  font-size: 14px;
}

.site-footer p,
.site-footer a,
.footer-bottom {
  color: var(--muted);
  font-size: 14px;
}

.site-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.site-footer a:hover {
  color: var(--text);
}

.footer-bottom {
  border-top: 1px solid var(--line);
  padding-top: 16px;
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  font-size: 13px;
}

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

table {
  width: 100%;
  border-collapse: collapse;
  min-width: 700px;
}

th,
td {
  padding: 14px 16px;
  text-align: left;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

th {
  background: var(--accent-soft);
  font-weight: 650;
}

td {
  color: var(--muted);
}

td strong {
  color: var(--text);
}

.media-row {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 20px;
  align-items: center;
}

.media-frame {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--surface);
}

.media-frame img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
}

.doc-block {
  margin-bottom: 0;
}

.doc-block ol,
.doc-block ul {
  margin: 0;
  padding-left: 18px;
}

@keyframes fadeup {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.hero-copy,
.hero-visual,
.section-head {
  animation: fadeup 0.55s ease both;
}

.hero-visual {
  animation-delay: 0.08s;
}

@media (max-width: 960px) {
  .hero-grid,
  .how-grid,
  .media-row,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .grid-5,
  .grid-3,
  .steps,
  .compat-grid,
  .capability-list {
    grid-template-columns: 1fr 1fr;
  }

  .nav-links {
    display: none;
  }
}

@media (max-width: 640px) {
  .container {
    width: min(var(--max), calc(100% - 28px));
  }

  .hero {
    padding-top: 48px;
  }

  .grid-5,
  .grid-3,
  .steps,
  .compat-grid,
  .capability-list,
  .trust-row {
    grid-template-columns: 1fr;
  }

  .section {
    padding: 48px 0;
  }
}