:root {
  color-scheme: light;
  --ink: #1a1c1f;
  --muted: #5d6673;
  --line: #dce2e8;
  --paper: #f7f9fb;
  --white: #ffffff;
  --blue: #2457d6;
  --blue-dark: #173b94;
  --green: #1d7a59;
  --orange: #b95c1c;
  --shadow: 0 18px 50px rgba(31, 42, 55, 0.14);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.5;
}

.skip-link {
  position: absolute;
  top: -48px;
  left: 16px;
  z-index: 100;
  padding: 10px 14px;
  border-radius: 8px;
  background: var(--blue);
  color: white;
  font-weight: 700;
  text-decoration: none;
}

.skip-link:focus {
  top: 12px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.section-lead,
.cta-lead {
  margin: 14px 0 0;
  max-width: 720px;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.55;
}

.hero-highlights {
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  color: var(--muted);
}

.hero-highlights li {
  position: relative;
  padding-left: 18px;
  margin-top: 8px;
}

.hero-highlights li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--green);
  font-weight: 900;
}

a {
  color: inherit;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 64px;
  padding: 0 28px;
  background: rgba(255, 255, 255, 0.9);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(16px);
}

.brand,
nav {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand {
  text-decoration: none;
  font-weight: 750;
}

.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 8px;
  color: white;
  background: var(--blue);
  font-size: 14px;
}

nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
}

.lang-switch {
  padding: 4px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--blue-dark) !important;
  font-weight: 700;
  background: white;
}

html[lang="zh-CN"] body {
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Source Han Sans SC", ui-sans-serif, system-ui, sans-serif;
}

.hero,
.band,
.final-cta {
  max-width: 1180px;
  margin: 0 auto;
  padding: 84px 28px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.02fr) minmax(360px, 0.98fr);
  gap: 52px;
  align-items: center;
  min-height: calc(100vh - 64px);
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  max-width: 760px;
  font-size: 58px;
  line-height: 1.02;
  letter-spacing: 0;
}

h2 {
  margin: 0;
  font-size: 38px;
  line-height: 1.12;
  letter-spacing: 0;
}

h3 {
  margin: 0 0 10px;
  font-size: 20px;
  letter-spacing: 0;
}

.subtitle {
  max-width: 660px;
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 20px;
  line-height: 1.55;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: 8px;
  font-weight: 750;
  text-decoration: none;
}

.button.primary {
  color: white;
  background: var(--blue);
}

.button.secondary {
  color: var(--blue-dark);
  background: white;
  border-color: var(--line);
}

.hero-panel {
  margin: 0;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
  box-shadow: var(--shadow);
}

.screen {
  padding: 18px;
  border: 1px solid #cbd5df;
  border-radius: 8px;
  background: #eef3f8;
}

.window-row {
  display: flex;
  gap: 8px;
  margin-bottom: 18px;
}

.window-row span {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: #8996a5;
}

.grid-preview {
  display: grid;
  grid-template-columns: repeat(5, minmax(40px, 1fr));
  gap: 8px;
}

.grid-preview span {
  display: grid;
  place-items: center;
  aspect-ratio: 1;
  border: 1px solid #b8c4d2;
  border-radius: 6px;
  background: white;
  color: var(--blue-dark);
  font-weight: 800;
}

.keyboard-strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-top: 18px;
  color: var(--green);
  font-weight: 750;
}

/* Compact inline keys in body copy */
kbd {
  display: inline-block;
  vertical-align: baseline;
  margin: 0 2px;
  padding: 1px 6px;
  border: 1px solid #b8c4d2;
  border-radius: 4px;
  background: white;
  color: var(--ink);
  font-family: inherit;
  font-size: 0.9em;
  font-weight: 800;
  line-height: 1.35;
  white-space: nowrap;
}

.keyboard-strip kbd {
  min-width: 38px;
  margin: 0;
  padding: 8px 10px;
  border-radius: 6px;
  font-size: inherit;
  text-align: center;
  line-height: normal;
  white-space: normal;
}

.band {
  border-top: 1px solid var(--line);
}

.section-copy {
  max-width: 720px;
  margin-bottom: 30px;
}

.three,
.four,
.compare,
.use-grid {
  display: grid;
  gap: 16px;
}

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

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

article,
.use-grid p,
.check-list p {
  margin: 0;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
}

article p,
.check-list p,
.use-grid p {
  color: var(--muted);
  line-height: 1.65;
}

article strong {
  display: block;
  margin-bottom: 8px;
  font-size: 18px;
}

.check-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: step;
}

.steps li {
  margin: 0;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
}

.steps li strong {
  display: block;
  margin-bottom: 10px;
  font-size: 18px;
  line-height: 1.5;
}

.steps li p {
  margin: 0;
  color: var(--muted);
  line-height: 1.65;
}

.zone-table-wrap {
  margin-top: 28px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
}

.zone-table-title {
  margin: 0 0 14px;
  font-size: 18px;
}

.zone-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
}

.zone-table th,
.zone-table td {
  padding: 10px 12px;
  border: 1px solid var(--line);
  text-align: left;
}

.zone-table th {
  background: var(--paper);
  font-weight: 800;
}

.faq-list {
  display: grid;
  gap: 12px;
}

.faq-list details {
  padding: 18px 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
}

.faq-list summary {
  cursor: pointer;
  font-weight: 750;
  font-size: 17px;
}

.faq-list p {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.55;
}

.faq-list code {
  font-size: 0.92em;
}

.requirements {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.site-footer {
  max-width: 1180px;
  margin: 0 auto;
  padding: 40px 28px 56px;
  border-top: 1px solid var(--line);
  text-align: center;
  color: var(--muted);
  font-size: 14px;
}

.site-footer p {
  margin: 0 0 10px;
}

.site-footer nav {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 16px;
  margin: 16px 0;
}

.site-footer nav a {
  color: var(--blue-dark);
  text-decoration: none;
  font-weight: 700;
}

.footer-copy {
  margin-top: 18px !important;
  font-size: 13px;
}

.check-list p::before {
  content: "✓";
  margin-right: 10px;
  color: var(--green);
  font-weight: 900;
}

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

.label {
  display: inline-flex;
  margin-bottom: 18px;
  padding: 6px 10px;
  border-radius: 999px;
  color: white;
  font-size: 13px;
  font-weight: 800;
}

.label.before {
  background: var(--orange);
}

.label.after {
  background: var(--green);
}

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

.use-grid p {
  color: var(--ink);
  font-weight: 750;
}

.final-cta {
  text-align: center;
  border-top: 1px solid var(--line);
}

.final-cta .actions {
  justify-content: center;
}

@media (max-width: 880px) {
  .topbar {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
    padding: 14px 20px;
  }

  nav {
    flex-wrap: wrap;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  h1 {
    font-size: 42px;
  }

  h2 {
    font-size: 30px;
  }

  .three,
  .four,
  .compare,
  .check-list,
  .use-grid,
  .steps {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 520px) {
  .hero,
  .band,
  .final-cta {
    padding: 58px 18px;
  }

  h1 {
    font-size: 34px;
  }

  .subtitle {
    font-size: 17px;
  }

  .grid-preview {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 6px;
  }

  .grid-preview span {
    min-width: 0;
    font-size: 13px;
  }

  .zone-table-wrap {
    overflow-x: auto;
  }

  .zone-table {
    min-width: 520px;
  }

  .button {
    width: 100%;
  }
}