:root {
  --bby-bg: #0f0a1a;
  --bby-surface: rgba(255, 255, 255, 0.06);
  --bby-surface-strong: rgba(255, 255, 255, 0.1);
  --bby-text: #f4f0ff;
  --bby-muted: #b8aed4;
  --bby-rose: #ff3d7f;
  --bby-rose-dim: #c92d63;
  --bby-cyan: #40e0d0;
  --bby-violet: #7c4dff;
  --bby-gold: #ffc857;
  --bby-radius: 18px;
  --bby-radius-sm: 12px;
  --bby-shadow: 0 18px 48px rgba(0, 0, 0, 0.45);
  --bby-header-h: 58px;
  --bby-promo-h: 0px;
  --bby-dl-h: 0px;
  --bby-max: 1120px;
  --bby-font: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--bby-font);
  font-size: 16px;
  line-height: 1.75;
  color: var(--bby-text);
  background: var(--bby-bg);
  background-image:
    radial-gradient(ellipse 80% 50% at 10% -10%, rgba(124, 77, 255, 0.35), transparent),
    radial-gradient(ellipse 60% 40% at 95% 20%, rgba(255, 61, 127, 0.22), transparent),
    radial-gradient(ellipse 50% 30% at 50% 100%, rgba(64, 224, 208, 0.12), transparent);
  min-height: 100vh;
}

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

a {
  color: var(--bby-cyan);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--bby-rose);
}

.bby-wrap {
  width: min(var(--bby-max), calc(100% - 2rem));
  margin-inline: auto;
}

/* Promo top */
.bby-promo-top {
  position: relative;
  z-index: 120;
  background: linear-gradient(90deg, rgba(124, 77, 255, 0.25), rgba(255, 61, 127, 0.2));
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  padding: 0.55rem 0 0.35rem;
}

.bby-promo-top p {
  margin: 0 0 0.35rem;
  text-align: center;
  font-size: 0.82rem;
  color: var(--bby-muted);
  letter-spacing: 0.04em;
}

#ads {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 0.35rem;
  background: transparent;
  margin: 0;
  padding-bottom: 0.35rem;
}

#ads .bby-ad-cell {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 70px;
}

#ads img {
  width: 58px;
  height: 58px;
  object-fit: cover;
  border-radius: 16px;
  border: 2px solid rgba(255, 255, 255, 0.12);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.35);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

#ads a:hover img {
  transform: translateY(-3px) scale(1.05);
  box-shadow: 0 12px 28px rgba(255, 61, 127, 0.35);
}

#ads figcaption {
  margin-top: 0.2rem;
  font-size: 10px;
  color: var(--bby-muted);
  text-align: center;
  max-width: 68px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Header */
.bby-header {
  position: sticky;
  top: 0;
  z-index: 110;
  background: rgba(15, 10, 26, 0.88);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.07);
}

.bby-header-inner {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  min-height: var(--bby-header-h);
  gap: 1rem;
  position: relative;
}

.bby-nav-slot {
  position: relative;
  margin-left: auto;
  flex-shrink: 0;
}

.bby-brand {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  color: var(--bby-text);
  font-weight: 700;
  font-size: 1.05rem;
}

.bby-brand img {
  width: 36px;
  height: 36px;
  border-radius: 10px;
}

.bby-nav-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 12px;
  background: var(--bby-surface);
  color: var(--bby-text);
  font-size: 0;
  cursor: pointer;
  padding: 0;
}

.bby-nav-icon,
.bby-nav-icon::before,
.bby-nav-icon::after {
  display: block;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: var(--bby-text);
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.bby-nav-icon {
  position: relative;
}

.bby-nav-icon::before,
.bby-nav-icon::after {
  content: "";
  position: absolute;
  left: 0;
}

.bby-nav-icon::before {
  top: -6px;
}

.bby-nav-icon::after {
  top: 6px;
}

.bby-nav-slot:has(.bby-nav-open) .bby-nav-icon {
  background: transparent;
}

.bby-nav-slot:has(.bby-nav-open) .bby-nav-icon::before {
  top: 0;
  transform: rotate(45deg);
}

.bby-nav-slot:has(.bby-nav-open) .bby-nav-icon::after {
  top: 0;
  transform: rotate(-45deg);
}

.bby-nav-panel ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: none;
  flex-direction: column;
  gap: 0.25rem;
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  left: auto;
  min-width: 11.5rem;
  background: rgba(22, 14, 38, 0.97);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--bby-radius-sm);
  padding: 0.75rem;
  box-shadow: var(--bby-shadow);
  z-index: 130;
}

.bby-nav-panel.bby-nav-open ul {
  display: flex;
}

.bby-nav-panel a {
  display: block;
  padding: 0.55rem 0.75rem;
  border-radius: 8px;
  color: var(--bby-muted);
  font-size: 0.92rem;
}

.bby-nav-panel a:hover,
.bby-nav-panel a[aria-current="page"] {
  color: var(--bby-text);
  background: rgba(255, 61, 127, 0.15);
}

/* Sticky download bar */
#bby-dl-bar {
  position: fixed;
  top: var(--bby-header-h);
  left: 0;
  right: 0;
  z-index: 105;
  background: rgba(18, 11, 32, 0.96);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(64, 224, 208, 0.2);
  padding: 0.45rem 0.75rem;
  transform: translateY(-110%);
  opacity: 0;
  pointer-events: none;
  transition: transform 0.28s ease, opacity 0.28s ease;
}

#bby-dl-bar.bby-dl-visible {
  transform: translateY(0);
  opacity: 1;
  pointer-events: auto;
}

#bby-dl-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.4rem;
  max-width: var(--bby-max);
  margin: 0 auto;
}

#bby-dl-grid .bby-dl-cell a {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
  color: var(--bby-muted);
  font-size: 9px;
  text-align: center;
}

#bby-dl-grid img {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  object-fit: cover;
}

body.bby-dl-pad {
  padding-top: var(--bby-dl-h);
}

/* Hero */
.bby-hero {
  padding: 2.5rem 0 3rem;
  position: relative;
  overflow: hidden;
}

.bby-hero::before {
  content: "";
  position: absolute;
  width: 320px;
  height: 320px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 61, 127, 0.25), transparent 70%);
  top: -80px;
  right: -60px;
  pointer-events: none;
}

.bby-hero-layout {
  display: grid;
  gap: 2rem;
  align-items: center;
}

.bby-hero-badge {
  display: inline-block;
  padding: 0.3rem 0.85rem;
  border-radius: 999px;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  background: linear-gradient(135deg, rgba(124, 77, 255, 0.4), rgba(255, 61, 127, 0.35));
  border: 1px solid rgba(255, 255, 255, 0.12);
  margin-bottom: 1rem;
}

.bby-hero h1 {
  font-size: clamp(1.65rem, 5vw, 2.35rem);
  line-height: 1.25;
  margin: 0 0 1rem;
  background: linear-gradient(135deg, #fff 30%, var(--bby-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.bby-hero-lead {
  font-size: 1.02rem;
  color: var(--bby-muted);
  margin: 0;
}

.bby-phone-shell {
  position: relative;
  max-width: 280px;
  margin: 0 auto;
  padding: 0.65rem;
  border-radius: 28px;
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.14), rgba(255, 255, 255, 0.04));
  border: 1px solid rgba(255, 255, 255, 0.15);
  box-shadow: var(--bby-shadow), 0 0 60px rgba(124, 77, 255, 0.2);
}

.bby-phone-shell img {
  border-radius: 22px;
}

.bby-phone-glow {
  position: absolute;
  inset: -20%;
  background: radial-gradient(circle, rgba(64, 224, 208, 0.15), transparent 60%);
  z-index: -1;
}

/* Sections */
.bby-section {
  padding: 3rem 0;
}

.bby-section-wave {
  position: relative;
}

.bby-section-wave::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255, 61, 127, 0.4), transparent);
}

.bby-section-tint {
  background: rgba(255, 255, 255, 0.03);
}

.bby-eyebrow {
  display: inline-block;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--bby-rose);
  margin-bottom: 0.5rem;
}

.bby-section h2 {
  font-size: clamp(1.35rem, 4vw, 1.85rem);
  margin: 0 0 1rem;
  line-height: 1.3;
}

.bby-section h3 {
  font-size: 1.12rem;
  margin: 0 0 0.5rem;
  color: var(--bby-cyan);
}

.bby-prose p {
  margin: 0 0 1rem;
  color: var(--bby-muted);
}

.bby-prose p:last-child {
  margin-bottom: 0;
}

/* Cards */
.bby-mosaic {
  display: grid;
  gap: 1rem;
  margin-top: 1.5rem;
}

.bby-tile {
  padding: 1.25rem;
  border-radius: var(--bby-radius);
  background: var(--bby-surface);
  border: 1px solid rgba(255, 255, 255, 0.08);
  backdrop-filter: blur(8px);
  transition: border-color 0.25s ease, transform 0.25s ease;
}

.bby-tile:hover {
  border-color: rgba(255, 61, 127, 0.35);
  transform: translateY(-2px);
}

.bby-tile-icon {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.bby-tile p {
  margin: 0;
  font-size: 0.92rem;
  color: var(--bby-muted);
}

/* Split layout */
.bby-split {
  display: grid;
  gap: 2rem;
  align-items: center;
}

.bby-split-reverse .bby-split-media {
  order: -1;
}

.bby-frame {
  border-radius: var(--bby-radius);
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: var(--bby-shadow);
}

/* Stats row */
.bby-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
  margin: 1.5rem 0;
}

.bby-stat {
  text-align: center;
  padding: 1rem;
  border-radius: var(--bby-radius-sm);
  background: var(--bby-surface);
  border: 1px solid rgba(64, 224, 208, 0.15);
}

.bby-stat strong {
  display: block;
  font-size: 1.4rem;
  color: var(--bby-cyan);
}

.bby-stat span {
  font-size: 0.8rem;
  color: var(--bby-muted);
}

/* Breadcrumb */
.bby-crumb {
  padding: 1rem 0 0.5rem;
  font-size: 0.85rem;
  color: var(--bby-muted);
}

.bby-crumb a {
  color: var(--bby-muted);
}

.bby-crumb a:hover {
  color: var(--bby-cyan);
}

.bby-crumb span {
  margin: 0 0.35rem;
  opacity: 0.5;
}

/* Legal / inner pages */
.bby-page-head {
  padding: 1.5rem 0 2rem;
}

.bby-page-head h1 {
  font-size: clamp(1.5rem, 4vw, 2rem);
  margin: 0 0 0.75rem;
}

.bby-legal h2 {
  font-size: 1.2rem;
  margin: 2rem 0 0.75rem;
  color: var(--bby-text);
}

.bby-legal h3 {
  font-size: 1.05rem;
  margin: 1.25rem 0 0.5rem;
}

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

.bby-legal ul {
  padding-left: 1.25rem;
}

/* Footer */
.bby-footer {
  margin-top: 3rem;
  padding: 2rem 0;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  background: rgba(0, 0, 0, 0.25);
}

.bby-footer-grid {
  display: grid;
  gap: 1.5rem;
}

.bby-footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
}

.bby-footer-nav a {
  font-size: 0.88rem;
  color: var(--bby-muted);
}

.bby-footer-copy {
  font-size: 0.82rem;
  color: rgba(184, 174, 212, 0.7);
  margin: 0;
}

/* Error pages */
.bby-error {
  text-align: center;
  padding: 3rem 0 4rem;
}

.bby-error-code {
  font-size: 4rem;
  font-weight: 800;
  line-height: 1;
  background: linear-gradient(135deg, var(--bby-rose), var(--bby-violet));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Reveal animation */
.bby-fade {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.bby-fade.bby-inview {
  opacity: 1;
  transform: translateY(0);
}

/* Desktop */
@media (min-width: 768px) {
  .bby-nav-slot {
    margin-left: auto;
    display: flex;
    align-items: center;
  }

  .bby-nav-toggle {
    display: none;
  }

  .bby-nav-panel ul {
    display: flex;
    flex-direction: row;
    position: static;
    background: none;
    border: none;
    box-shadow: none;
    padding: 0;
    gap: 0.15rem;
    min-width: 0;
  }

  .bby-nav-panel a {
    padding: 0.45rem 0.85rem;
    font-size: 0.88rem;
  }

  .bby-hero-layout {
    grid-template-columns: 1.1fr 0.9fr;
  }

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

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

  .bby-split {
    grid-template-columns: 1fr 1fr;
  }

  .bby-split-reverse {
    direction: rtl;
  }

  .bby-split-reverse > * {
    direction: ltr;
  }

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

  #bby-dl-grid {
    grid-template-columns: repeat(8, 1fr);
  }

  .bby-footer-grid {
    grid-template-columns: 1fr auto;
    align-items: center;
  }
}

@media (min-width: 1024px) {
  .bby-mosaic-4 {
    grid-template-columns: repeat(4, 1fr);
  }
}