/* Base */
:root {
  --bg: #ffffff;
  --text: #1f2937;
  --muted: rgba(31, 41, 55, 0.7);
  --line: rgba(17, 24, 39, 0.08);
  --shadow: 0 18px 45px rgba(17, 24, 39, 0.14);
  --shadow-soft: 0 10px 26px rgba(17, 24, 39, 0.1);
  --radius: 16px;
  --accent: #5cd4c5;
  --accent-2: #3a86ff;
  --accent-strong: #ff8a3d;
  --header-h: 72px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Noto Sans CJK SC", "Noto Sans SC", sans-serif;
  color: var(--text);
  background: var(--bg);
  overflow-x: hidden;
}

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

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

.container {
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
}

/* Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-h);
  z-index: 20;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(17, 24, 39, 0.05);
  transition: box-shadow 200ms ease, background 200ms ease, border-color 200ms ease;
}

.site-header.is-scrolled {
  background: rgba(255, 255, 255, 0.94);
  border-bottom-color: rgba(17, 24, 39, 0.08);
  box-shadow: 0 8px 24px rgba(17, 24, 39, 0.08);
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  letter-spacing: 0.2px;
}

.brand-mark {
  flex: 0 0 auto;
  box-shadow: 0 10px 26px rgba(58, 134, 255, 0.18);
  border-radius: 14px;
}

.brand-text {
  font-size: 16px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 26px;
  color: rgba(31, 41, 55, 0.82);
  font-size: 14px;
}

.nav-link {
  position: relative;
  padding: 8px 0;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 2px;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border-radius: 99px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 220ms ease;
}

.nav-link:hover::after,
.nav-link.is-active::after {
  transform: scaleX(1);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  height: 40px;
  padding: 0 16px;
  border-radius: 10px;
  border: 1px solid transparent;
  cursor: pointer;
  user-select: none;
  transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease, border-color 160ms ease;
  font-size: 14px;
  font-weight: 600;
  white-space: nowrap;
}

.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn-icon svg {
  display: block;
}

.btn-primary {
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  color: #fff;
  box-shadow: 0 12px 26px rgba(58, 134, 255, 0.2);
  border: 0;
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 34px rgba(58, 134, 255, 0.26);
}

.header-cta {
  border: 0;
}

/* Hero */
.hero {
  position: relative;
  padding-top: calc(var(--header-h) + 28px);
  padding-bottom: 88px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(6, 37, 88, 0.78) 0%, rgba(0, 92, 190, 0.64) 42%, rgba(18, 156, 144, 0.58) 100%),
    radial-gradient(1200px 600px at 20% 30%, rgba(92, 212, 197, 0.55) 0%, rgba(92, 212, 197, 0) 62%),
    radial-gradient(1000px 520px at 72% 36%, rgba(58, 134, 255, 0.52) 0%, rgba(58, 134, 255, 0) 64%);
}

.hero-inner {
  position: relative;
  display: grid;
  grid-template-columns: 1.05fr 1.25fr;
  align-items: center;
  gap: 40px;
}

.hero-left {
  padding: 12px 0;
}

.hero-title {
  margin: 0;
  font-size: clamp(36px, 4.2vw, 54px);
  font-weight: 800;
  letter-spacing: 0.5px;
  color: #ffffff;
  text-shadow: 0 18px 44px rgba(0, 0, 0, 0.26);
}

.hero-subtitle {
  margin: 18px 0 24px;
  color: rgba(255, 255, 255, 0.92);
  text-shadow: 0 14px 34px rgba(0, 0, 0, 0.22);
  line-height: 1.75;
  font-size: 16px;
  max-width: 520px;
}

.hero-actions {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.btn-download {
  height: 50px;
  padding: 0 18px;
  border-radius: 12px;
  background: var(--accent-strong);
  color: #fff;
  box-shadow: 0 16px 36px rgba(255, 138, 61, 0.28);
  width: fit-content;
}

.btn-download:hover {
  transform: translateY(-1px);
  box-shadow: 0 22px 44px rgba(255, 138, 61, 0.34);
}

.hero-meta {
  color: rgba(255, 255, 255, 0.86);
  font-size: 13px;
}

.hero-right {
  display: flex;
  justify-content: flex-end;
}

.hero-device {
  width: min(640px, 100%);
  filter: drop-shadow(0 22px 46px rgba(0, 0, 0, 0.2));
}

.scroll-hint {
  position: absolute;
  left: 50%;
  bottom: 18px;
  transform: translateX(-50%);
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: rgba(255, 255, 255, 0.88);
  font-size: 13px;
  padding: 8px 14px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.18);
}

.scroll-hint-dot {
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: #fff;
  opacity: 0.85;
  animation: hintPulse 1.4s ease-in-out infinite;
}

@keyframes hintPulse {
  0%,
  100% {
    transform: translateY(0);
    opacity: 0.9;
  }
  50% {
    transform: translateY(4px);
    opacity: 0.55;
  }
}

/* Sections */
.section {
  padding: 84px 0;
  background: #fff;
}

.features {
  padding-top: 90px;
}

.section-header {
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: center;
  text-align: center;
  margin-bottom: 34px;
}

.section-title {
  margin: 0;
  font-size: 30px;
  letter-spacing: 0.2px;
}

.section-desc {
  margin: 0;
  color: var(--muted);
  line-height: 1.7;
  max-width: 700px;
  font-size: 14px;
}

/* Feature grid */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.feature-card {
  background: #fff;
  border: 1px solid rgba(17, 24, 39, 0.07);
  border-radius: var(--radius);
  padding: 26px 18px 22px;
  text-align: center;
  box-shadow: 0 6px 18px rgba(17, 24, 39, 0.06);
  transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.feature-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-soft);
  border-color: rgba(58, 134, 255, 0.22);
}

.feature-icon {
  width: 66px;
  height: 66px;
  margin: 0 auto 14px;
  border-radius: 18px;
  background: linear-gradient(135deg, rgba(92, 212, 197, 0.22), rgba(58, 134, 255, 0.16));
  color: rgba(79, 195, 184, 1);
  display: grid;
  place-items: center;
}

.feature-icon svg {
  width: 34px;
  height: 34px;
}

.feature-title {
  margin: 0;
  font-size: 16px;
  font-weight: 800;
  letter-spacing: 0.2px;
}

.feature-desc {
  margin: 10px 0 0;
  color: rgba(31, 41, 55, 0.62);
  font-size: 13px;
  line-height: 1.7;
}

/* Guide */
.guide {
  background: linear-gradient(180deg, #fff 0%, rgba(58, 134, 255, 0.03) 100%);
}

.guide-card {
  border: 1px solid rgba(17, 24, 39, 0.07);
  background: rgba(255, 255, 255, 0.8);
  border-radius: 22px;
  box-shadow: 0 14px 44px rgba(17, 24, 39, 0.08);
  padding: 26px;
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.guide-item {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 14px;
  border-radius: 18px;
  border: 1px solid rgba(17, 24, 39, 0.06);
  background: #fff;
}

.guide-badge {
  width: 34px;
  height: 34px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-weight: 800;
  color: #0f172a;
  background: linear-gradient(135deg, rgba(92, 212, 197, 0.26), rgba(58, 134, 255, 0.18));
}

.guide-title {
  font-weight: 800;
  font-size: 14px;
}

.guide-desc {
  color: rgba(31, 41, 55, 0.68);
  font-size: 13px;
  line-height: 1.65;
  margin-top: 6px;
}

/* Footer */
.site-footer {
  border-top: 1px solid rgba(17, 24, 39, 0.07);
  background: #fff;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: row;
  flex-wrap: wrap;
  text-align: center;
  gap: 14px;
  color: rgba(31, 41, 55, 0.68);
  font-size: 13px;
  padding: 18px 0;
}

.icp {
  color: rgba(31, 41, 55, 0.68);
}

.icp:hover {
  color: rgba(58, 134, 255, 0.9);
}

/* Reveal */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 520ms ease, transform 520ms ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive */
@media (max-width: 980px) {
  .hero-inner {
    grid-template-columns: 1fr;
    gap: 26px;
  }

  .hero-right {
    justify-content: center;
  }

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

  .guide-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  :root {
    --header-h: 66px;
  }

  .nav {
    display: none;
  }

  .container {
    width: min(1120px, calc(100% - 28px));
  }

  .btn {
    height: 38px;
  }

  .btn-download {
    width: 100%;
    justify-content: center;
  }

  .hero-actions {
    align-items: stretch;
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }

  .footer-inner {
    justify-content: center;
    align-items: center;
    height: auto;
    padding: 16px 0;
  }
}