:root {
  --sky-top: #d9f3ff;
  --sky-mid: #8ec8f5;
  --sky-deep: #2f6fd6;
  --ink: #0d1b2a;
  --ink-soft: #3a4a5c;
  --ink-faint: #6b7c8f;
  --paper: #f4f9fd;
  --line: rgba(15, 45, 80, 0.1);
  --accent: #1a6fd4;
  --max: 1080px;
  --font-display: "Noto Serif SC", "Songti SC", "STSong", serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  background: var(--paper);
  -webkit-text-size-adjust: 100%;
}

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

a {
  color: inherit;
  text-decoration: none;
}

.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 22px;
  background: rgba(244, 249, 253, 0.72);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s ease, background 0.25s ease;
}

.site-nav.is-solid {
  border-bottom-color: var(--line);
  background: rgba(244, 249, 253, 0.92);
}

.nav-brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: 0.06em;
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  padding: 8px 16px;
  border-radius: 999px;
  background: var(--ink);
  color: #fff;
  font-size: 0.9rem;
  font-weight: 550;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-cta:hover {
  transform: translateY(-1px);
  opacity: 0.92;
}

.hero {
  position: relative;
  min-height: 100svh;
  display: grid;
  align-items: center;
  overflow: hidden;
  color: var(--ink);
  background:
    radial-gradient(ellipse 80% 55% at 72% 28%, rgba(255, 255, 255, 0.65) 0%, transparent 55%),
    radial-gradient(ellipse 60% 50% at 18% 78%, rgba(61, 184, 255, 0.35) 0%, transparent 60%),
    linear-gradient(165deg, var(--sky-top) 0%, var(--sky-mid) 46%, #4a8fe0 100%);
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(1.5px 1.5px at 12% 22%, rgba(255, 255, 255, 0.7), transparent),
    radial-gradient(1.5px 1.5px at 28% 48%, rgba(255, 255, 255, 0.55), transparent),
    radial-gradient(1.5px 1.5px at 54% 18%, rgba(255, 255, 255, 0.65), transparent),
    radial-gradient(1.5px 1.5px at 78% 36%, rgba(255, 255, 255, 0.45), transparent),
    radial-gradient(1.5px 1.5px at 88% 68%, rgba(255, 255, 255, 0.5), transparent);
  opacity: 0.9;
  pointer-events: none;
  animation: star-drift 18s ease-in-out infinite alternate;
}

.hero-inner {
  position: relative;
  z-index: 1;
  width: min(100% - 40px, var(--max));
  margin: 0 auto;
  padding: 96px 0;
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 40px;
  align-items: center;
}

.hero-copy {
  max-width: 34rem;
}

.brand-mark {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 18px;
  opacity: 0;
  transform: translateY(18px);
  animation: rise-in 0.9s cubic-bezier(0.22, 1, 0.36, 1) 0.05s forwards;
}

.brand-mark img {
  width: 72px;
  height: 72px;
  border-radius: 18px;
  box-shadow: 0 18px 40px rgba(20, 70, 140, 0.22);
}

.brand-name {
  font-family: var(--font-display);
  font-size: clamp(3.6rem, 8vw, 5.6rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.08em;
  margin: 0;
  text-shadow: 0 2px 24px rgba(255, 255, 255, 0.35);
}

.hero-headline {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 3.2vw, 1.85rem);
  font-weight: 600;
  line-height: 1.35;
  opacity: 0;
  transform: translateY(18px);
  animation: rise-in 0.9s cubic-bezier(0.22, 1, 0.36, 1) 0.18s forwards;
}

.hero-lead {
  margin: 0 0 20px;
  font-size: 1.05rem;
  color: var(--ink-soft);
  max-width: 28rem;
  opacity: 0;
  transform: translateY(18px);
  animation: rise-in 0.9s cubic-bezier(0.22, 1, 0.36, 1) 0.3s forwards;
}

.scroll-hint {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.92rem;
  font-weight: 550;
  color: var(--ink);
  opacity: 0;
  transform: translateY(18px);
  animation: rise-in 0.9s cubic-bezier(0.22, 1, 0.36, 1) 0.42s forwards;
}

.scroll-hint::after {
  content: "";
  width: 7px;
  height: 7px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: rotate(45deg);
  opacity: 0.7;
}

.scroll-hint:hover {
  text-decoration: underline;
}

.btn-store {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 14px 22px;
  border-radius: 14px;
  background: var(--ink);
  color: #fff;
  transition: transform 0.22s ease, background 0.22s ease;
}

.btn-store:hover {
  transform: translateY(-2px);
  background: #152536;
}

.btn-store svg {
  width: 22px;
  height: 22px;
  flex-shrink: 0;
}

.btn-store .btn-kicker {
  display: block;
  font-size: 0.72rem;
  opacity: 0.75;
  line-height: 1.2;
}

.btn-store .btn-label {
  display: block;
  font-size: 1.05rem;
  font-weight: 650;
  letter-spacing: 0.02em;
  line-height: 1.25;
}

.btn-ghost {
  display: inline-flex;
  align-items: center;
  padding: 14px 18px;
  border-radius: 14px;
  border: 1px solid rgba(13, 27, 42, 0.18);
  background: rgba(255, 255, 255, 0.55);
  color: var(--ink);
  font-weight: 550;
  transition: background 0.2s ease, border-color 0.2s ease;
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.8);
  border-color: rgba(13, 27, 42, 0.28);
}

.hero-device {
  justify-self: end;
  width: min(100%, 340px);
  opacity: 0;
  transform: translateY(28px) scale(0.98);
  animation: rise-in 1s cubic-bezier(0.22, 1, 0.36, 1) 0.25s forwards;
}

.device-frame {
  position: relative;
  margin: 0;
  border-radius: 36px;
  padding: 12px;
  background: linear-gradient(160deg, rgba(255, 255, 255, 0.72), rgba(255, 255, 255, 0.28));
  border: 1px solid rgba(255, 255, 255, 0.65);
  box-shadow: 0 28px 60px rgba(24, 70, 140, 0.28);
}

.device-screen {
  position: relative;
  border-radius: 26px;
  overflow: hidden;
  background: #0b0b0d;
  aspect-ratio: 9 / 19.5;
}

.device-screen-light {
  background: #f7f7f8;
}

.device-shot {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
}

.device-caption {
  margin: 12px 0 2px;
  text-align: center;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--ink-soft);
}

.showcase-band {
  background: linear-gradient(180deg, #eef6fc 0%, #f7fafc 100%);
  border-block: 1px solid var(--line);
}

.showcase-inner {
  width: min(100% - 40px, var(--max));
  margin: 0 auto;
  padding: 105px 0;
  display: grid;
  grid-template-columns: 1fr minmax(220px, 320px);
  gap: 40px;
  align-items: center;
}

.showcase-inner-flip {
  grid-template-columns: minmax(220px, 320px) 1fr;
}

.showcase-inner-flip .showcase-copy {
  text-align: right;
  justify-self: stretch;
}

.showcase-inner-flip .showcase-copy .section-lead {
  margin-left: auto;
}

.showcase-copy .section-lead {
  margin-bottom: 0;
}

.showcase-device {
  justify-self: end;
  width: min(100%, 320px);
}

.showcase-inner-flip .showcase-device {
  justify-self: start;
}

.mid-cta {
  display: flex;
  justify-content: center;
  padding-top: 36px;
  padding-bottom: 20px;
}

.section {
  width: min(100% - 40px, var(--max));
  margin: 0 auto;
  padding: 72px 0;
}

.section-kicker {
  margin: 0 0 10px;
  font-size: 0.85rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
}

.section-title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 4vw, 2.25rem);
  line-height: 1.25;
  font-weight: 700;
}

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

.feature-rail {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line);
}

.feature-row {
  display: grid;
  grid-template-columns: 88px 1fr;
  gap: 20px;
  padding: 26px 0;
  border-bottom: 1px solid var(--line);
  align-items: start;
}

.feature-index {
  font-family: var(--font-display);
  font-size: 1.7rem;
  line-height: 1;
  color: var(--sky-deep);
  opacity: 0.5;
}

.feature-row h3 {
  margin: 0 0 8px;
  font-size: 1.15rem;
  font-weight: 700;
}

.feature-row p {
  margin: 0;
  color: var(--ink-soft);
  max-width: 42rem;
}

.note-band {
  background: linear-gradient(120deg, rgba(217, 243, 255, 0.9), rgba(142, 200, 245, 0.45));
  border-block: 1px solid var(--line);
}

.note-band .section {
  padding: 48px 0;
}

.note-band p {
  margin: 0;
  max-width: 44rem;
  color: var(--ink-soft);
}

.download-panel {
  text-align: center;
  padding: 64px 0 80px;
}

.download-panel .section-lead {
  margin-left: auto;
  margin-right: auto;
}

.download-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
  align-items: stretch;
}

.download-actions .btn-store,
.download-actions .btn-ghost {
  box-sizing: border-box;
  min-width: 200px;
  min-height: 64px;
  padding: 12px 22px;
  border-radius: 14px;
  justify-content: center;
}

.download-actions .btn-ghost {
  gap: 0;
}

.download-actions .btn-ghost .btn-kicker {
  display: block;
  font-size: 0.72rem;
  opacity: 0.65;
  line-height: 1.2;
  font-weight: 500;
}

.download-actions .btn-ghost .btn-label {
  display: block;
  font-size: 1.05rem;
  font-weight: 650;
  letter-spacing: 0.02em;
  line-height: 1.25;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: #eaf4fb;
  padding: 36px 0 48px;
}

.footer-inner {
  width: min(100% - 40px, var(--max));
  margin: 0 auto;
  display: grid;
  gap: 18px;
}

.footer-brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.2rem;
}

.footer-meta,
.footer-links {
  color: var(--ink-faint);
  font-size: 0.88rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 18px;
}

.footer-links a:hover {
  color: var(--accent);
  text-decoration: underline;
}

@keyframes rise-in {
  to {
    opacity: 1;
    transform: none;
  }
}

@keyframes star-drift {
  from { transform: translate3d(0, 0, 0); }
  to { transform: translate3d(-12px, 8px, 0); }
}

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

  .brand-mark,
  .hero-headline,
  .hero-lead,
  .scroll-hint,
  .hero-device {
    opacity: 1;
    transform: none;
  }
}

@media (max-width: 860px) {
  .hero-inner {
    grid-template-columns: 1fr;
    padding: 108px 0 48px;
    gap: 28px;
  }

  .hero-device {
    justify-self: center;
    width: min(100%, 300px);
  }

  .showcase-inner,
  .showcase-inner-flip {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 56px 0;
  }

  /* 手机端：文字在上、预览在下（与看图段一致） */
  .showcase-inner-flip .showcase-copy {
    order: -1;
    text-align: left;
    justify-self: stretch;
  }

  .showcase-inner-flip .showcase-copy .section-lead {
    margin-left: 0;
    max-width: none;
  }

  .showcase-device,
  .showcase-inner-flip .showcase-device {
    justify-self: center;
    width: min(100%, 260px);
  }

  .hero-showcase {
    padding-top: 96px;
    padding-bottom: 48px;
  }

  .feature-row {
    grid-template-columns: 48px 1fr;
    gap: 12px;
  }

  .feature-index {
    font-size: 1.35rem;
  }
}

@media (max-width: 480px) {
  .site-nav {
    padding: 12px 16px;
  }

  .hero-inner,
  .section,
  .showcase-inner,
  .footer-inner {
    width: min(100% - 28px, var(--max));
  }

  .brand-name {
    letter-spacing: 0.04em;
  }

  .brand-mark img {
    width: 56px;
    height: 56px;
    border-radius: 14px;
  }

  .btn-store,
  .btn-ghost {
    width: 100%;
    justify-content: center;
  }

  .download-actions {
    flex-direction: column;
  }
}