:root {
  color-scheme: light dark;
  --brand: #0066ff;
  --brand-hover: #0055df;
  --brand-bright: #2382ff;
  --brand-soft: rgba(0, 102, 255, 0.10);
  --cyan: #27dbe8;
  --green: #18b96b;
  --orange: #ff8a00;
  --red: #ff3b3b;
  --background: #f5f7fb;
  --surface: #ffffff;
  --surface-raised: rgba(255, 255, 255, 0.90);
  --surface-subtle: #f7f9fd;
  --text: #101521;
  --secondary: #5f6878;
  --tertiary: #8a93a2;
  --border: rgba(16, 21, 33, 0.10);
  --shadow: 0 24px 80px rgba(16, 47, 104, 0.11);
  --shadow-small: 0 10px 30px rgba(16, 47, 104, 0.08);
  --page-width: 1160px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --brand: #3385ff;
    --brand-hover: #66a3ff;
    --brand-bright: #5a9dff;
    --brand-soft: rgba(0, 102, 255, 0.19);
    --cyan: #45e5ef;
    --green: #35d98d;
    --orange: #ffa43b;
    --red: #ff5d5d;
    --background: #070a10;
    --surface: #121721;
    --surface-raised: rgba(18, 23, 33, 0.90);
    --surface-subtle: #171d28;
    --text: #f5f7fb;
    --secondary: #a8b1c0;
    --tertiary: #7f899a;
    --border: rgba(255, 255, 255, 0.10);
    --shadow: none;
    --shadow-small: none;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  overflow-x: hidden;
  background:
    radial-gradient(circle at 78% 3%, rgba(0, 102, 255, 0.20), transparent 34rem),
    radial-gradient(circle at 12% 28%, rgba(39, 219, 232, 0.08), transparent 28rem),
    var(--background);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", "Noto Sans SC", sans-serif;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }
img { display: block; max-width: 100%; }
button, a { -webkit-tap-highlight-color: transparent; }

.lang.zh { display: none; }
html[data-language="zh-Hans"] .lang.en { display: none; }
html[data-language="zh-Hans"] .lang.zh { display: inline; }

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

.nav-wrap {
  position: sticky;
  top: 0;
  z-index: 50;
  padding: 12px 20px;
  background: rgba(245, 247, 251, 0.80);
  border-bottom: 1px solid transparent;
  backdrop-filter: saturate(165%) blur(20px);
  -webkit-backdrop-filter: saturate(165%) blur(20px);
}

@media (prefers-color-scheme: dark) {
  .nav-wrap { background: rgba(7, 10, 16, 0.80); }
}

.nav {
  width: min(100%, var(--page-width));
  min-height: 52px;
  margin-inline: auto;
  display: flex;
  align-items: center;
  gap: 22px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
  color: var(--text);
  text-decoration: none;
  font-size: 17px;
  font-weight: 780;
  letter-spacing: -0.025em;
}

.brand img {
  width: 30px;
  height: 30px;
  border-radius: 9px;
  box-shadow: 0 7px 18px rgba(0, 102, 255, 0.23);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-left: auto;
}

.nav-links a {
  padding: 8px 11px;
  border-radius: 9px;
  color: var(--secondary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 630;
  white-space: nowrap;
}

.nav-links a:hover,
.nav-links a:focus-visible,
.nav-links a[aria-current="page"] {
  color: var(--text);
  background: var(--brand-soft);
  outline: none;
}

.language-switcher {
  display: inline-flex;
  flex: 0 0 auto;
  padding: 3px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface-raised);
}

.language-switcher button {
  min-width: 40px;
  border: 0;
  border-radius: 999px;
  padding: 6px 9px;
  background: transparent;
  color: var(--secondary);
  font: inherit;
  font-size: 12px;
  cursor: pointer;
}

.language-switcher button[aria-pressed="true"] {
  background: var(--brand);
  color: #fff;
  font-weight: 750;
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.04fr) minmax(390px, 0.96fr);
  align-items: center;
  gap: clamp(46px, 7vw, 92px);
  min-height: 710px;
  padding: 82px 0 92px;
}

.hero-copy-wrap { position: relative; z-index: 2; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 19px;
  padding: 7px 12px;
  border: 1px solid rgba(0, 102, 255, 0.20);
  border-radius: 999px;
  background: var(--brand-soft);
  color: var(--brand);
  font-size: 13px;
  font-weight: 750;
}

.eyebrow::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--green) 17%, transparent);
}

h1 {
  max-width: 760px;
  margin: 0;
  font-size: clamp(3.25rem, 7.2vw, 6rem);
  line-height: 0.98;
  letter-spacing: -0.065em;
}

.gradient-text {
  color: var(--brand);
  background: linear-gradient(100deg, var(--brand) 4%, #1684ff 56%, #18c7dd);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-copy {
  max-width: 650px;
  margin: 27px 0 0;
  color: var(--secondary);
  font-size: clamp(1.05rem, 2vw, 1.24rem);
  line-height: 1.68;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 31px;
}

.button {
  min-height: 50px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 11px 19px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--surface-raised);
  color: var(--text);
  text-decoration: none;
  font-weight: 730;
  box-shadow: var(--shadow-small);
  transition: transform 160ms ease, border-color 160ms ease, background 160ms ease;
}

.button:hover { transform: translateY(-2px); border-color: rgba(0, 102, 255, 0.38); }
.button.primary { border-color: var(--brand); background: var(--brand); color: #fff; }
.button.primary:hover { background: var(--brand-hover); }
.button-icon { font-size: 18px; line-height: 1; }

.availability {
  margin: 16px 0 0;
  color: var(--tertiary);
  font-size: 13px;
}

.device-stage {
  position: relative;
  min-height: 590px;
  display: grid;
  place-items: center;
}

.device-glow {
  position: absolute;
  width: 470px;
  height: 470px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(0, 102, 255, 0.28), rgba(39, 219, 232, 0.08) 45%, transparent 70%);
  filter: blur(6px);
}

.phone {
  position: relative;
  width: min(100%, 390px);
  min-height: 570px;
  padding: 24px 20px 21px;
  border: 1px solid rgba(255, 255, 255, 0.34);
  border-radius: 42px;
  background: var(--surface);
  background: color-mix(in srgb, var(--surface) 94%, var(--brand) 6%);
  box-shadow: 0 45px 110px rgba(5, 32, 83, 0.24), inset 0 0 0 6px rgba(128, 138, 155, 0.10);
  transform: rotate(1.2deg);
}

.phone::before {
  content: "";
  position: absolute;
  top: 10px;
  left: 50%;
  width: 82px;
  height: 7px;
  transform: translateX(-50%);
  border-radius: 99px;
  background: var(--border);
}

.app-bar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 3px 18px;
}

.app-title { font-size: 25px; font-weight: 800; letter-spacing: -0.04em; }
.app-state { margin-left: auto; color: var(--secondary); font-size: 12px; font-weight: 700; }
.app-state::before { content: ""; display: inline-block; width: 7px; height: 7px; margin-right: 6px; border-radius: 50%; background: var(--green); }
.info-chip { width: 34px; height: 34px; display: grid; place-items: center; border: 1px solid var(--border); border-radius: 50%; background: var(--surface-raised); color: var(--brand); font-weight: 800; }

.diagnostic-card {
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 24px;
  background: var(--surface);
  box-shadow: var(--shadow-small);
}

.card-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.card-heading h2 { margin: 0; font-size: 18px; line-height: 1.2; }
.unit { color: var(--tertiary); font-size: 12px; font-weight: 550; }
.rtt-values { display: flex; gap: 15px; text-align: right; }
.rtt-values span { display: block; color: var(--tertiary); font-size: 10px; line-height: 1.25; }
.rtt-values strong { display: block; margin-top: 3px; font-size: 14px; }
.network-name { margin: 12px 0 3px; color: var(--secondary); font-size: 12px; }
.network-name strong { color: var(--text); }

.chart {
  position: relative;
  overflow: hidden;
  height: 190px;
  margin-top: 10px;
  border: 1px solid var(--border);
  border-radius: 17px;
  background:
    linear-gradient(to bottom, transparent 32%, var(--border) 33%, transparent 34%, transparent 65%, var(--border) 66%, transparent 67%),
    linear-gradient(to right, transparent 32%, var(--border) 33%, transparent 34%, transparent 65%, var(--border) 66%, transparent 67%),
    var(--surface-subtle);
}

.chart canvas { width: 100%; height: 100%; }
.chart-label { position: absolute; z-index: 2; color: var(--tertiary); font-size: 9px; pointer-events: none; }
.chart-label.top { top: 7px; left: 8px; }
.chart-label.bottom { bottom: 7px; right: 9px; }

.metrics-card {
  margin-top: 13px;
  padding: 16px 18px;
  border: 1px solid var(--border);
  border-radius: 22px;
  background: var(--surface);
  box-shadow: var(--shadow-small);
}

.metrics-title { margin-bottom: 10px; font-size: 13px; font-weight: 760; }
.metrics-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0; }
.metric { padding: 8px 10px; }
.metric:nth-child(odd) { border-right: 1px solid var(--border); padding-left: 0; }
.metric:nth-child(even) { padding-right: 0; }
.metric:nth-child(n+3) { border-top: 1px solid var(--border); }
.metric small { display: block; color: var(--tertiary); font-size: 10px; }
.metric strong { display: block; margin-top: 2px; font-size: 17px; }
.metric .safe { color: var(--green); }
.metric .orange { color: var(--orange); }
.metric .blue { color: var(--brand); }

.proof-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin-bottom: 24px;
  border: 1px solid var(--border);
  border-radius: 22px;
  background: var(--surface-raised);
  box-shadow: var(--shadow-small);
}

.proof-item { padding: 21px 22px; text-align: center; }
.proof-item + .proof-item { border-left: 1px solid var(--border); }
.proof-item strong { display: block; color: var(--brand); font-size: 1.35rem; line-height: 1.2; }
.proof-item span { display: block; margin-top: 5px; color: var(--secondary); font-size: 13px; }

section { padding: 92px 0; scroll-margin-top: 74px; }
.section-heading { max-width: 760px; margin-bottom: 40px; }
.section-kicker { margin-bottom: 10px; color: var(--brand); font-size: 13px; font-weight: 790; letter-spacing: 0.04em; text-transform: uppercase; }
.section-heading h2 { margin: 0; font-size: clamp(2.15rem, 5vw, 4.2rem); line-height: 1.05; letter-spacing: -0.055em; }
.section-heading p { max-width: 680px; margin: 19px 0 0; color: var(--secondary); font-size: 1.08rem; }

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

.feature-card {
  min-height: 265px;
  padding: 27px;
  border: 1px solid var(--border);
  border-radius: 24px;
  background: var(--surface);
  box-shadow: var(--shadow-small);
  transition: transform 180ms ease, border-color 180ms ease;
}

.feature-card:hover { transform: translateY(-4px); border-color: rgba(0, 102, 255, 0.30); }
.feature-icon { width: 46px; height: 46px; display: grid; place-items: center; margin-bottom: 24px; border-radius: 15px; background: var(--brand-soft); color: var(--brand); font-size: 22px; font-weight: 760; }
.feature-icon.orange { color: var(--orange); background: var(--brand-soft); background: color-mix(in srgb, var(--orange) 11%, transparent); }
.feature-icon.green { color: var(--green); background: var(--brand-soft); background: color-mix(in srgb, var(--green) 11%, transparent); }
.feature-card h3 { margin: 0; font-size: 1.24rem; letter-spacing: -0.02em; }
.feature-card p { margin: 10px 0 0; color: var(--secondary); }

.workflow-section { border-block: 1px solid var(--border); background: var(--surface); background: color-mix(in srgb, var(--surface) 48%, transparent); }
.workflow { display: grid; grid-template-columns: minmax(0, 0.88fr) minmax(400px, 1.12fr); gap: clamp(44px, 8vw, 100px); align-items: center; }

.timeline {
  position: relative;
  display: grid;
  gap: 13px;
  padding-left: 30px;
}

.timeline::before { content: ""; position: absolute; top: 22px; bottom: 22px; left: 9px; width: 2px; border-radius: 99px; background: linear-gradient(var(--brand), var(--orange), var(--green)); }
.timeline-item { position: relative; padding: 20px 22px; border: 1px solid var(--border); border-radius: 18px; background: var(--surface); box-shadow: var(--shadow-small); }
.timeline-item::before { content: ""; position: absolute; top: 25px; left: -27px; width: 12px; height: 12px; border: 3px solid var(--background); border-radius: 50%; background: var(--brand); }
.timeline-item:nth-child(2)::before { background: var(--orange); }
.timeline-item:nth-child(3)::before { background: var(--green); }
.timeline-time { color: var(--tertiary); font-variant-numeric: tabular-nums; font-size: 12px; }
.timeline-item strong { display: block; margin-top: 4px; font-size: 1.02rem; }
.timeline-item p { margin: 4px 0 0; color: var(--secondary); font-size: 14px; }

.privacy-panel {
  position: relative;
  overflow: hidden;
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(300px, 0.8fr);
  gap: 48px;
  align-items: center;
  padding: clamp(36px, 7vw, 68px);
  border: 1px solid var(--border);
  border-radius: 30px;
  background:
    radial-gradient(circle at 92% 15%, rgba(39, 219, 232, 0.17), transparent 18rem),
    linear-gradient(135deg, var(--brand-soft), transparent 65%),
    var(--surface);
  box-shadow: var(--shadow);
}

.privacy-panel h2 { margin: 0; font-size: clamp(2.1rem, 5vw, 3.8rem); line-height: 1.05; letter-spacing: -0.05em; }
.privacy-panel p { max-width: 680px; margin: 18px 0 0; color: var(--secondary); font-size: 1.06rem; }
.privacy-points { display: grid; gap: 12px; }
.privacy-point { display: flex; align-items: center; gap: 13px; padding: 14px 16px; border: 1px solid var(--border); border-radius: 15px; background: var(--surface-raised); color: var(--secondary); font-size: 14px; }
.privacy-point::before { content: "✓"; width: 25px; height: 25px; display: grid; place-items: center; flex: 0 0 auto; border-radius: 50%; background: var(--brand-soft); background: color-mix(in srgb, var(--green) 15%, transparent); color: var(--green); font-weight: 900; }

.echo-panel {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(380px, 1.1fr);
  gap: clamp(44px, 8vw, 92px);
  align-items: center;
}

.server-card { overflow: hidden; border: 1px solid rgba(255, 255, 255, 0.11); border-radius: 24px; background: #09111f; color: #eaf1ff; box-shadow: 0 34px 90px rgba(5, 22, 52, 0.28); }
.server-bar { min-height: 46px; display: flex; align-items: center; gap: 7px; padding: 0 16px; border-bottom: 1px solid rgba(255, 255, 255, 0.08); color: #7d8ba5; font-size: 12px; }
.server-dot { width: 10px; height: 10px; border-radius: 50%; background: #ff5f57; }
.server-dot:nth-child(2) { background: #febc2e; }
.server-dot:nth-child(3) { background: #28c840; }
.server-name { margin-left: auto; }
.server-lines { padding: 28px 25px 31px; font-family: "SFMono-Regular", Consolas, monospace; font-size: 13px; line-height: 1.9; }
.server-lines p { margin: 0; }
.server-lines .prompt { color: var(--cyan); }
.server-lines .muted { color: #7d8ba5; }
.server-lines .success { color: #61dda9; }

.cta {
  margin-bottom: 74px;
  padding: clamp(42px, 7vw, 70px);
  border-radius: 30px;
  background: linear-gradient(135deg, #0066ff, #0754dc 62%, #05379d);
  color: #fff;
  text-align: center;
  box-shadow: 0 32px 90px rgba(0, 74, 194, 0.27);
}

.cta h2 { max-width: 780px; margin: 0 auto; font-size: clamp(2.15rem, 5vw, 4.3rem); line-height: 1.05; letter-spacing: -0.055em; }
.cta p { max-width: 660px; margin: 18px auto 0; color: rgba(255, 255, 255, 0.78); font-size: 1.08rem; }
.cta .actions { justify-content: center; }
.cta .button.primary { border-color: #fff; background: #fff; color: #0754dc; }
.cta .button.secondary { border-color: rgba(255, 255, 255, 0.32); background: rgba(255, 255, 255, 0.10); color: #fff; box-shadow: none; }

footer { border-top: 1px solid var(--border); }
.footer-row { min-height: 112px; display: flex; align-items: center; gap: 24px; color: var(--secondary); font-size: 13px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 18px; margin-left: auto; }
.footer-links a { text-decoration: none; }
.footer-links a:hover { color: var(--brand); }

@media (max-width: 980px) {
  .nav-links a:nth-child(2) { display: none; }
  .hero { grid-template-columns: 1fr; padding-top: 62px; }
  .hero-copy-wrap { text-align: center; }
  .hero-copy { margin-inline: auto; }
  .actions { justify-content: center; }
  .device-stage { min-height: 600px; }
  .feature-grid { grid-template-columns: 1fr 1fr; }
  .workflow, .echo-panel { grid-template-columns: 1fr; }
  .privacy-panel { grid-template-columns: 1fr; }
}

@media (max-width: 700px) {
  .container { width: min(calc(100% - 26px), var(--page-width)); }
  .nav-wrap { padding-inline: 13px; }
  .nav { gap: 10px; }
  .brand span { display: none; }
  .nav-links { overflow-x: auto; scrollbar-width: none; }
  .nav-links::-webkit-scrollbar { display: none; }
  .nav-links a { padding-inline: 9px; }
  .nav-links a:nth-child(3) { display: none; }
  .language-switcher button { min-width: 35px; padding-inline: 7px; }
  .hero { min-height: auto; padding: 52px 0 66px; }
  h1 { font-size: clamp(3rem, 15vw, 4.7rem); }
  .device-stage { min-height: 535px; }
  .phone { width: min(100%, 356px); min-height: 526px; border-radius: 36px; transform: none; }
  .chart { height: 162px; }
  .proof-strip { grid-template-columns: 1fr 1fr; }
  .proof-item:nth-child(3) { border-left: 0; border-top: 1px solid var(--border); }
  .proof-item:nth-child(4) { border-top: 1px solid var(--border); }
  section { padding: 72px 0; }
  .feature-grid { grid-template-columns: 1fr; }
  .feature-card { min-height: 0; }
  .workflow { gap: 40px; }
  .privacy-panel { gap: 34px; border-radius: 24px; }
  .echo-panel { gap: 38px; }
  .cta { margin-bottom: 48px; border-radius: 24px; }
  .footer-row { flex-direction: column; justify-content: center; padding: 28px 0; text-align: center; }
  .footer-links { justify-content: center; margin-left: 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .button, .feature-card { transition: none; }
  .button:hover, .feature-card:hover { transform: none; }
}