:root {
  --bg: #0b0718;
  --bg-2: #130c2a;
  --card: #1a1236;
  --line: #2c2252;
  --fg: #f3f0ff;
  --muted: #a99fcb;
  --cyan: #6be4f7;
  --magenta: #e05ad0;
  --blue: #4f8df6;
  --radius: 20px;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--cyan); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }

/* Language switch: English by default, Chinese when <html> has class "lang-zh". */
.zh { display: none; }
html.lang-zh .en { display: none; }
html.lang-zh .zh { display: revert; }
html.lang-zh span.zh, html.lang-zh a.zh { display: inline; }

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 20px; }

/* Header */
header.top {
  position: sticky; top: 0; z-index: 10;
  background: rgba(11, 7, 24, 0.78);
  backdrop-filter: saturate(160%) blur(16px);
  -webkit-backdrop-filter: saturate(160%) blur(16px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}
header.top .wrap { display: flex; align-items: center; gap: 16px; height: 58px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--fg); font-weight: 650; letter-spacing: -0.01em; }
.brand:hover { text-decoration: none; }
.brand img { width: 30px; height: 30px; border-radius: 8px; }
nav.links { margin-left: auto; display: flex; align-items: center; gap: 18px; font-size: 15px; }
nav.links a { color: var(--muted); }
nav.links a:hover, nav.links a[aria-current] { color: var(--fg); text-decoration: none; }
.lang {
  font: inherit; font-size: 14px; color: var(--fg); cursor: pointer;
  background: transparent; border: 1px solid var(--line); border-radius: 999px; padding: 4px 12px;
}
.lang:hover { border-color: var(--muted); }

/* Hero */
.hero { position: relative; overflow: hidden; padding: 72px 0 0; text-align: center; }
.hero::before {
  content: ""; position: absolute; inset: 0;
  background:
    radial-gradient(60% 50% at 50% 0%, rgba(124, 77, 255, 0.35), transparent 70%),
    radial-gradient(40% 30% at 85% 30%, rgba(224, 90, 208, 0.18), transparent 70%),
    radial-gradient(40% 30% at 15% 40%, rgba(107, 228, 247, 0.14), transparent 70%);
  pointer-events: none;
}
.grid {
  position: absolute; left: -50%; right: -50%; bottom: 0; height: 55%;
  background-image:
    linear-gradient(rgba(150, 110, 255, 0.35) 1px, transparent 1px),
    linear-gradient(90deg, rgba(150, 110, 255, 0.35) 1px, transparent 1px);
  background-size: 56px 56px;
  transform: perspective(420px) rotateX(62deg);
  transform-origin: 50% 100%;
  mask-image: linear-gradient(to top, #000 10%, transparent 85%);
  -webkit-mask-image: linear-gradient(to top, #000 10%, transparent 85%);
  pointer-events: none;
}
.hero .wrap { position: relative; }
.hero .icon { width: 112px; height: 112px; border-radius: 26px; margin: 0 auto 26px; box-shadow: 0 18px 50px rgba(124, 77, 255, 0.45); }
.hero h1 { font-size: clamp(40px, 7vw, 68px); line-height: 1.04; letter-spacing: -0.035em; margin: 0 0 18px; font-weight: 750; }
.hero h1 .accent {
  background: linear-gradient(90deg, var(--cyan), var(--blue) 45%, var(--magenta));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero p.lead { font-size: clamp(18px, 2.4vw, 21px); color: var(--muted); max-width: 620px; margin: 0 auto 30px; }
.cta { display: inline-flex; align-items: center; gap: 10px; padding: 13px 24px; border-radius: 999px; font-weight: 600; font-size: 17px; color: #0b0718; background: var(--fg); }
.cta:hover { text-decoration: none; background: #fff; }
.cta svg { width: 20px; height: 20px; }
.note { margin-top: 14px; font-size: 14px; color: var(--muted); }

.phones { display: flex; justify-content: center; align-items: flex-end; gap: 22px; margin-top: 56px; padding-bottom: 0; }
.phone {
  width: 250px; flex: none; border-radius: 38px; overflow: hidden;
  border: 6px solid #241a44; background: #000;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.55), 0 0 0 1px rgba(255, 255, 255, 0.06);
}
.phone.side { width: 220px; opacity: 0.92; margin-bottom: -40px; }
.phone.center { margin-bottom: -80px; }
.phones-clip { overflow: hidden; padding-bottom: 0; }

/* Sections */
section { padding: 120px 0 40px; }
section + section { padding-top: 64px; }
.eyebrow { font-size: 13px; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; color: var(--cyan); margin: 0 0 10px; }
h2 { font-size: clamp(28px, 4vw, 40px); line-height: 1.12; letter-spacing: -0.025em; margin: 0 0 14px; }
.sub { color: var(--muted); max-width: 640px; margin: 0 0 36px; font-size: 18px; }

.cards { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.card h3 { margin: 12px 0 6px; font-size: 18px; letter-spacing: -0.01em; }
.card p { margin: 0; color: var(--muted); font-size: 15px; line-height: 1.5; }
.badge { width: 40px; height: 40px; border-radius: 12px; display: grid; place-items: center; }
.badge svg { width: 22px; height: 22px; }

.split { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
.split .shot { justify-self: center; }
.split .shot .phone { width: 280px; }
ul.checks { list-style: none; padding: 0; margin: 0; }
ul.checks li { position: relative; padding: 10px 0 10px 30px; border-bottom: 1px solid var(--line); }
ul.checks li:last-child { border-bottom: 0; }
ul.checks li::before {
  content: ""; position: absolute; left: 2px; top: 19px; width: 12px; height: 12px; border-radius: 4px;
  background: linear-gradient(135deg, var(--cyan), var(--magenta));
}
.formats { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 6px; }
.formats span { font: 600 13px/1 ui-monospace, "SF Mono", Menlo, monospace; padding: 7px 10px; border-radius: 8px; background: var(--bg-2); border: 1px solid var(--line); color: var(--fg); }
.group { margin-bottom: 22px; }
.group b { display: block; font-size: 15px; color: var(--muted); font-weight: 600; }

.pro {
  border-radius: 28px; padding: 44px; border: 1px solid var(--line);
  background:
    radial-gradient(80% 120% at 100% 0%, rgba(224, 90, 208, 0.22), transparent 60%),
    radial-gradient(80% 120% at 0% 100%, rgba(107, 228, 247, 0.16), transparent 60%),
    var(--card);
}
.pro p { color: var(--muted); max-width: 680px; }

/* Plain text pages (support, privacy) */
.doc { max-width: 720px; padding: 56px 20px 40px; }
.doc h1 { font-size: clamp(32px, 5vw, 44px); letter-spacing: -0.03em; line-height: 1.1; margin: 0 0 8px; }
.doc h2 { font-size: 21px; margin: 36px 0 8px; letter-spacing: -0.01em; }
.doc p, .doc li { color: #d9d3f0; }
.doc .muted { color: var(--muted); font-size: 15px; }

footer { border-top: 1px solid var(--line); margin-top: 80px; padding: 28px 0 48px; color: var(--muted); font-size: 14px; }
footer .wrap { display: flex; flex-wrap: wrap; gap: 10px 22px; align-items: center; }
footer a { color: var(--muted); }
footer .copy { margin-right: auto; }

@media (max-width: 900px) {
  .cards { grid-template-columns: 1fr 1fr; }
  .split { grid-template-columns: 1fr; gap: 32px; }
  .split .shot { order: 2; }
}
@media (max-width: 640px) {
  nav.links a.hide-sm { display: none; }
  .hero { padding-top: 48px; }
  .phone.side { display: none; }
  .phone.center { width: 240px; }
  .cards { grid-template-columns: 1fr; }
  .pro { padding: 28px 22px; }
  section { padding-top: 110px; }
}