:root {
  --bg: #070b12;
  --bg-elev: #0c121c;
  --ink: #e8eef7;
  --ink-muted: #8b9bb0;
  --line: rgba(148, 183, 210, 0.14);
  --accent: #3dd6c6;
  --accent-dim: rgba(61, 214, 198, 0.16);
  --accent-glow: rgba(61, 214, 198, 0.35);
  --danger-soft: #f0a0a0;
  --font-sans: "IBM Plex Sans", "PingFang SC", "Noto Sans SC", system-ui, sans-serif;
  --font-display: "Syne", "IBM Plex Sans", "PingFang SC", sans-serif;
  --max: 68rem;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  color-scheme: dark;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 1.05rem;
  line-height: 1.6;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
  text-underline-offset: 0.18em;
}

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

.shell {
  position: relative;
  overflow-x: clip;
}

.shell::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -2;
  background:
    radial-gradient(900px 520px at 12% -10%, rgba(61, 214, 198, 0.14), transparent 60%),
    radial-gradient(700px 480px at 88% 8%, rgba(64, 120, 220, 0.12), transparent 55%),
    var(--bg);
}

.shell::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 20%, #000 20%, transparent 75%);
  pointer-events: none;
  opacity: 0.55;
}

.wrap {
  width: min(100% - 2.5rem, var(--max));
  margin-inline: auto;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.35rem 0 0.5rem;
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 0.55rem;
  color: var(--ink);
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: -0.03em;
}

.brand:hover {
  text-decoration: none;
}

.brand-mark {
  font-size: 1.25rem;
}

.brand-cn {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--ink-muted);
  letter-spacing: 0.08em;
}

.nav-links {
  display: flex;
  gap: 1.25rem;
  align-items: center;
  font-size: 0.92rem;
}

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

.nav-links a:hover {
  color: var(--ink);
  text-decoration: none;
}

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

.lang-switch {
  display: inline-flex;
  align-items: center;
}

.lang-switch select {
  appearance: none;
  -webkit-appearance: none;
  min-height: 2rem;
  padding: 0.25rem 1.75rem 0.25rem 0.7rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background:
    linear-gradient(45deg, transparent 50%, var(--ink-muted) 50%) calc(100% - 14px) / 5px 5px no-repeat,
    linear-gradient(135deg, var(--ink-muted) 50%, transparent 50%) calc(100% - 10px) / 5px 5px no-repeat,
    var(--bg-elev);
  color: var(--ink);
  font: inherit;
  font-size: 0.85rem;
  cursor: pointer;
}

.lang-switch select:hover,
.lang-switch select:focus {
  border-color: rgba(61, 214, 198, 0.45);
  outline: none;
}

.hero {
  padding: 12vh 0 8vh;
  min-height: min(88vh, 52rem);
  display: flex;
  flex-direction: column;
  justify-content: center;
  animation: rise 0.9s var(--ease) both;
}

.hero-kicker {
  margin: 0 0 1rem;
  font-size: 0.8rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--accent);
}

.hero h1 {
  margin: 0;
  max-width: 14ch;
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 8vw, 5.4rem);
  font-weight: 700;
  line-height: 0.98;
  letter-spacing: -0.045em;
}

.hero-lead {
  margin: 1.4rem 0 0;
  max-width: 34rem;
  color: var(--ink-muted);
  font-size: clamp(1.05rem, 2.2vw, 1.25rem);
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  margin-top: 2.2rem;
  animation: rise 1s var(--ease) 0.12s both;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  min-height: 2.85rem;
  padding: 0.7rem 1.25rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font: inherit;
  font-size: 0.95rem;
  font-weight: 560;
  cursor: pointer;
  transition: transform 0.25s var(--ease), background 0.25s var(--ease), border-color 0.25s var(--ease);
  text-decoration: none;
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-1px);
}

.btn-primary {
  color: #041016;
  background: var(--accent);
  box-shadow: 0 0 0 1px rgba(61, 214, 198, 0.25), 0 12px 40px var(--accent-glow);
}

.btn-primary:hover {
  background: #62e4d6;
}

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

.btn-ghost:hover {
  border-color: rgba(61, 214, 198, 0.45);
  background: var(--accent-dim);
}

.section {
  padding: 4.5rem 0 5.5rem;
  border-top: 1px solid var(--line);
  animation: rise 1s var(--ease) 0.2s both;
}

.section h2 {
  margin: 0 0 0.75rem;
  font-family: var(--font-display);
  font-size: clamp(1.55rem, 3vw, 2rem);
  letter-spacing: -0.03em;
}

.section-lead {
  margin: 0 0 2.2rem;
  max-width: 36rem;
  color: var(--ink-muted);
}

.feature-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1.5rem;
}

@media (min-width: 720px) {
  .feature-list {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.75rem;
  }
}

.feature-list li {
  padding-top: 1rem;
  border-top: 1px solid var(--line);
}

.feature-list h3 {
  margin: 0 0 0.45rem;
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.feature-list p {
  margin: 0;
  color: var(--ink-muted);
  font-size: 0.95rem;
}

.privacy-band {
  margin: 0;
  padding: 1.25rem 1.4rem;
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: linear-gradient(180deg, rgba(61, 214, 198, 0.06), transparent 70%);
  color: var(--ink-muted);
  font-size: 0.95rem;
}

.privacy-band strong {
  color: var(--ink);
  font-weight: 600;
}

.footer {
  padding: 2.5rem 0 3rem;
  border-top: 1px solid var(--line);
  color: var(--ink-muted);
  font-size: 0.88rem;
}

.footer-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 1.5rem;
  justify-content: space-between;
  align-items: center;
}

.footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

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

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

.legal {
  padding: 3rem 0 5rem;
}

.legal h1 {
  margin: 0 0 0.5rem;
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 2.75rem);
  letter-spacing: -0.03em;
}

.legal .meta {
  margin: 0 0 2rem;
  color: var(--ink-muted);
  font-size: 0.9rem;
}

.legal h2 {
  margin: 2rem 0 0.6rem;
  font-size: 1.15rem;
}

.legal p,
.legal li {
  color: var(--ink-muted);
}

.legal ul {
  padding-left: 1.2rem;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}