:root {
  --xbb-bg: #0c1220;
  --xbb-bg-soft: #121a2e;
  --xbb-surface: rgba(22, 32, 56, 0.72);
  --xbb-glass: rgba(255, 255, 255, 0.06);
  --xbb-line: rgba(255, 255, 255, 0.1);
  --xbb-text: #e8edf7;
  --xbb-muted: #9aa8c4;
  --xbb-cyan: #2dd4bf;
  --xbb-coral: #fb7185;
  --xbb-violet: #818cf8;
  --xbb-gold: #fbbf24;
  --xbb-radius: 18px;
  --xbb-header-h: 58px;
  --xbb-sticky-h: 0px;
  --xbb-font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--xbb-header-h) + var(--xbb-sticky-h) + 16px);
}

body {
  font-family: var(--xbb-font);
  background: var(--xbb-bg);
  color: var(--xbb-text);
  line-height: 1.78;
  font-size: 15px;
  overflow-x: hidden;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 10% -10%, rgba(45, 212, 191, 0.14), transparent 55%),
    radial-gradient(ellipse 60% 40% at 90% 20%, rgba(129, 140, 248, 0.12), transparent 50%),
    radial-gradient(ellipse 50% 30% at 50% 100%, rgba(251, 113, 133, 0.08), transparent 45%);
  pointer-events: none;
  z-index: 0;
}

a { color: var(--xbb-cyan); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--xbb-gold); }

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

.xbb-skip {
  position: absolute;
  left: -9999px;
  top: 0;
  padding: 8px 16px;
  background: var(--xbb-cyan);
  color: #000;
  z-index: 9999;
}
.xbb-skip:focus { left: 8px; top: 8px; }

/* Header */
.xbb-topbar {
  position: sticky;
  top: 0;
  z-index: 200;
  height: var(--xbb-header-h);
  background: rgba(12, 18, 32, 0.88);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--xbb-line);
}

.xbb-topbar-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 16px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.xbb-logo-link {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--xbb-text);
  font-weight: 700;
  font-size: 16px;
}
.xbb-logo-link img { border-radius: 10px; }

.xbb-burger {
  width: 42px;
  height: 42px;
  border: 1px solid var(--xbb-line);
  border-radius: 12px;
  background: var(--xbb-glass);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
}
.xbb-burger span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--xbb-text);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}

.xbb-drawer {
  position: fixed;
  top: var(--xbb-header-h);
  right: 0;
  width: min(280px, 85vw);
  height: calc(100vh - var(--xbb-header-h));
  background: rgba(18, 26, 46, 0.97);
  backdrop-filter: blur(20px);
  border-left: 1px solid var(--xbb-line);
  transform: translateX(100%);
  transition: transform 0.3s ease;
  z-index: 190;
  padding: 24px 0;
}
.xbb-drawer-open { transform: translateX(0); }

.xbb-drawer ul { list-style: none; }
.xbb-drawer li a {
  display: block;
  padding: 14px 24px;
  color: var(--xbb-muted);
  font-size: 15px;
  border-left: 3px solid transparent;
}
.xbb-drawer li a:hover,
.xbb-drawer li a[aria-current="page"] {
  color: var(--xbb-cyan);
  background: rgba(45, 212, 191, 0.06);
  border-left-color: var(--xbb-cyan);
}

.xbb-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 180;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s;
}
.xbb-overlay-show { opacity: 1; pointer-events: auto; }

body.xbb-noscroll { overflow: hidden; }

/* Sticky download bar */
.xbb-pin-dl {
  position: fixed;
  top: var(--xbb-header-h);
  left: 0;
  right: 0;
  z-index: 185;
  background: rgba(12, 18, 32, 0.94);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--xbb-line);
  padding: 8px 12px;
  transform: translateY(-110%);
  transition: transform 0.35s ease;
}
.xbb-pin-dl.xbb-pin-show { transform: translateY(0); }

.xbb-ad-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 8px;
  max-width: 1100px;
  margin: 0 auto;
}

.xbb-ad-row .xbb-ad-unit {
  width: calc(20% - 8px);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}
.xbb-ad-row .xbb-ad-unit a img {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  object-fit: cover;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.35);
  transition: transform 0.2s;
}
.xbb-ad-row .xbb-ad-unit a:hover img { transform: scale(1.06); }
.xbb-ad-row .xbb-ad-unit span {
  font-size: 10px;
  color: var(--xbb-muted);
  max-width: 64px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  text-align: center;
}

@media (min-width: 768px) {
  .xbb-ad-row .xbb-ad-unit { width: calc(12.5% - 8px); }
  .xbb-ad-row .xbb-ad-unit a img { width: 52px; height: 52px; }
}

/* Promo strip */
.xbb-promo-band {
  max-width: 1100px;
  margin: 0 auto;
  padding: 12px 16px;
  position: relative;
  z-index: 1;
}

/* Hero */
.xbb-banner {
  position: relative;
  z-index: 1;
  padding: 36px 16px 48px;
  max-width: 1100px;
  margin: 0 auto;
}

.xbb-banner-grid {
  display: grid;
  gap: 32px;
  align-items: center;
}

@media (min-width: 768px) {
  .xbb-banner-grid { grid-template-columns: 1.1fr 0.9fr; }
}

.xbb-banner h1 {
  font-size: clamp(1.5rem, 4.5vw, 2rem);
  line-height: 1.35;
  margin-bottom: 16px;
  background: linear-gradient(135deg, var(--xbb-text) 0%, var(--xbb-cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.xbb-lead {
  color: var(--xbb-muted);
  font-size: 15px;
  margin-bottom: 20px;
}

.xbb-chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.xbb-chip {
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 12px;
  background: var(--xbb-glass);
  border: 1px solid var(--xbb-line);
  color: var(--xbb-muted);
}

.xbb-phone-frame {
  position: relative;
  max-width: 280px;
  margin: 0 auto;
}
.xbb-phone-frame::before {
  content: "";
  position: absolute;
  inset: -20px;
  background: conic-gradient(from 180deg, var(--xbb-cyan), var(--xbb-violet), var(--xbb-coral), var(--xbb-cyan));
  border-radius: 32px;
  opacity: 0.35;
  filter: blur(24px);
  z-index: -1;
}
.xbb-phone-frame img {
  border-radius: 24px;
  border: 2px solid var(--xbb-line);
  box-shadow: 0 24px 48px rgba(0, 0, 0, 0.45);
}

/* Main content */
.xbb-wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 16px 64px;
  position: relative;
  z-index: 1;
}

.xbb-segment {
  margin-bottom: 48px;
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.xbb-segment.xbb-inview { opacity: 1; transform: translateY(0); }

.xbb-label {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--xbb-coral);
  margin-bottom: 10px;
  padding: 4px 10px;
  border-radius: 6px;
  background: rgba(251, 113, 133, 0.1);
}

.xbb-segment h2 {
  font-size: clamp(1.25rem, 3.5vw, 1.6rem);
  margin-bottom: 16px;
  color: var(--xbb-text);
}

.xbb-segment h3 {
  font-size: 1.05rem;
  margin: 20px 0 10px;
  color: var(--xbb-cyan);
}

.xbb-segment p { margin-bottom: 14px; color: var(--xbb-muted); }

/* Cards grid */
.xbb-tile-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(2, 1fr);
}
@media (min-width: 640px) { .xbb-tile-grid { grid-template-columns: repeat(4, 1fr); } }

.xbb-tile {
  padding: 20px 16px;
  border-radius: var(--xbb-radius);
  background: var(--xbb-surface);
  backdrop-filter: blur(10px);
  border: 1px solid var(--xbb-line);
  text-align: center;
  transition: border-color 0.25s, transform 0.25s;
}
.xbb-tile:hover {
  border-color: rgba(45, 212, 191, 0.35);
  transform: translateY(-3px);
}
.xbb-tile img {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  margin: 0 auto 12px;
  object-fit: cover;
}
.xbb-tile h3 { font-size: 14px; margin: 0 0 8px; color: var(--xbb-text); }
.xbb-tile p { font-size: 12px; margin: 0; line-height: 1.6; }

/* Zigzag media */
.xbb-zigzag {
  display: grid;
  gap: 28px;
  align-items: center;
}
@media (min-width: 768px) {
  .xbb-zigzag { grid-template-columns: 1fr 1fr; }
  .xbb-zigzag.xbb-zig-reverse .xbb-zig-media { order: 2; }
}

.xbb-zig-media img {
  border-radius: var(--xbb-radius);
  border: 1px solid var(--xbb-line);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.3);
}

/* Quote box */
.xbb-callout {
  padding: 20px 22px;
  border-radius: var(--xbb-radius);
  border-left: 4px solid var(--xbb-gold);
  background: linear-gradient(90deg, rgba(251, 191, 36, 0.08), transparent);
  margin: 20px 0;
}
.xbb-callout p { margin: 0; color: var(--xbb-text); font-size: 14px; }

/* Stats ribbon */
.xbb-stat-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin: 24px 0;
}
@media (min-width: 640px) { .xbb-stat-row { grid-template-columns: repeat(4, 1fr); } }

.xbb-stat {
  text-align: center;
  padding: 16px;
  border-radius: 14px;
  background: var(--xbb-glass);
  border: 1px solid var(--xbb-line);
}
.xbb-stat strong {
  display: block;
  font-size: 1.4rem;
  color: var(--xbb-cyan);
  margin-bottom: 4px;
}
.xbb-stat span { font-size: 12px; color: var(--xbb-muted); }

/* Download CTA */
.xbb-cta-band {
  text-align: center;
  padding: 40px 24px;
  border-radius: 24px;
  background: linear-gradient(145deg, rgba(45, 212, 191, 0.12), rgba(129, 140, 248, 0.08));
  border: 1px solid var(--xbb-line);
  margin-top: 32px;
}
.xbb-cta-band h2 { margin-bottom: 12px; }
.xbb-cta-band p { margin-bottom: 20px; }

.xbb-btn-get {
  display: inline-block;
  padding: 14px 36px;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--xbb-cyan), var(--xbb-violet));
  color: #0c1220;
  font-weight: 700;
  font-size: 15px;
  transition: transform 0.2s, box-shadow 0.2s;
  box-shadow: 0 8px 24px rgba(45, 212, 191, 0.25);
}
.xbb-btn-get:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(45, 212, 191, 0.35);
  color: #0c1220;
}

/* Breadcrumb */
.xbb-crumb {
  max-width: 1100px;
  margin: 0 auto;
  padding: 16px 16px 0;
  font-size: 13px;
  color: var(--xbb-muted);
  position: relative;
  z-index: 1;
}
.xbb-crumb a { color: var(--xbb-muted); }
.xbb-crumb a:hover { color: var(--xbb-cyan); }
.xbb-crumb span { color: var(--xbb-text); }

/* Legal / sub pages */
.xbb-doc {
  max-width: 800px;
  margin: 0 auto;
  padding: 24px 16px 64px;
  position: relative;
  z-index: 1;
}
.xbb-doc h1 {
  font-size: 1.6rem;
  margin-bottom: 8px;
}
.xbb-doc .xbb-doc-meta {
  color: var(--xbb-muted);
  font-size: 13px;
  margin-bottom: 28px;
}
.xbb-doc h2 {
  font-size: 1.15rem;
  margin: 28px 0 12px;
  color: var(--xbb-cyan);
}
.xbb-doc p, .xbb-doc li {
  color: var(--xbb-muted);
  margin-bottom: 12px;
  font-size: 14px;
}
.xbb-doc ul { padding-left: 20px; margin-bottom: 16px; }

/* Error pages */
.xbb-err {
  text-align: center;
  padding: 60px 16px 80px;
  position: relative;
  z-index: 1;
}
.xbb-err-code {
  font-size: 5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--xbb-coral), var(--xbb-violet));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 16px;
}
.xbb-err h1 { font-size: 1.4rem; margin-bottom: 12px; }
.xbb-err p { color: var(--xbb-muted); margin-bottom: 24px; max-width: 420px; margin-left: auto; margin-right: auto; }

/* Footer */
.xbb-foot {
  border-top: 1px solid var(--xbb-line);
  padding: 32px 16px;
  text-align: center;
  position: relative;
  z-index: 1;
}
.xbb-foot-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 20px;
  margin-bottom: 16px;
}
.xbb-foot-nav a {
  color: var(--xbb-muted);
  font-size: 14px;
}
.xbb-foot-copy {
  font-size: 12px;
  color: var(--xbb-muted);
  opacity: 0.7;
}