:root {
  --text: #24262b;
  --muted: #747982;
  --line: #e7ebf1;
  --blue-soft: #f7faff;
  --dark: #393b47;
  --red: #fc2d2d;
  --red-2: #fc634c;
  --shadow: 0 18px 50px rgba(26, 85, 140, .12);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
  color: var(--text);
  background: #fff;
  line-height: 1.5;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; }
button, input { font: inherit; }
.skip-link {
  position: fixed;
  left: 12px;
  top: -60px;
  z-index: 2000;
  background: #fff;
  color: #111;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: 6px;
}
.skip-link:focus { top: 12px; }
.shell {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
}
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: 68px;
  background: rgba(255, 255, 255, .96);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(0, 0, 0, 0);
}
.site-header.shadow { box-shadow: 0 4px 10px rgba(0, 0, 0, .06); }
.nav {
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand { display: inline-flex; align-items: center; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 34px;
  font-size: 16px;
}
.nav-links > a, .nav-group > a {
  position: relative;
  padding: 23px 0;
}
.nav-links .active::after,
.nav-links > a:hover::after,
.nav-group:hover > a::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 16px;
  width: 28px;
  height: 2px;
  background: var(--red);
  transform: translateX(-50%);
}
.nav-group { position: relative; }
.dropdown {
  display: none;
  position: absolute;
  left: 50%;
  top: 52px;
  width: 112px;
  transform: translateX(-50%);
  background: #fff;
  box-shadow: 0 4px 16px rgba(0, 0, 0, .08);
  border-radius: 8px;
  overflow: hidden;
}
.dropdown a {
  display: block;
  padding: 13px 12px;
  text-align: center;
}
.dropdown a:hover { background: #f2f3f5; }
.nav-group:hover .dropdown { display: block; }
.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  border: 0;
  background: transparent;
  padding: 10px;
}
.nav-toggle span {
  display: block;
  height: 2px;
  margin: 6px 0;
  background: #333;
}

.hero { min-height: 664px; overflow: hidden; }
.hero-grid {
  display: grid;
  grid-template-columns: .95fr 1.05fr;
  align-items: center;
  min-height: 664px;
  gap: 48px;
}
.hero-copy h1 {
  margin: 0;
  font-size: clamp(44px, 5vw, 58px);
  line-height: 1.4;
  font-weight: 700;
  letter-spacing: .04em;
}
.hero-copy p {
  margin: 28px 0 42px;
  font-size: clamp(19px, 2vw, 24px);
  color: #141414;
}
.primary-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 11px;
  min-width: 213px;
  min-height: 70px;
  padding: 0 30px;
  border-radius: 11px;
  color: #fff;
  font-weight: 600;
  font-size: 22px;
  background: linear-gradient(116deg, var(--red-2), var(--red) 66%);
  box-shadow: 0 4px 12px rgba(230, 38, 38, .2), 0 4px 24px rgba(254, 75, 75, .2);
}
.primary-btn img {
  width: 32px;
  height: 32px;
}
.primary-btn:hover { filter: brightness(.98); }
.hero-device {
  position: relative;
  min-height: 440px;
}
.mail-window {
  position: absolute;
  right: 0;
  top: 18px;
  width: min(680px, 100%);
  min-height: 410px;
  background: #fff;
  border-radius: 18px;
  box-shadow: 0 28px 80px rgba(36, 92, 160, .22);
  overflow: hidden;
}
.window-bar {
  height: 48px;
  background: #f2f5fb;
  display: flex;
  align-items: center;
  gap: 9px;
  padding-left: 22px;
}
.window-bar span {
  width: 11px;
  height: 11px;
  border-radius: 999px;
  background: #d2d8e3;
}
.mail-layout {
  display: grid;
  grid-template-columns: 88px 210px 1fr;
  min-height: 362px;
}
.mail-sidebar { background: #4b80fe; padding: 30px 24px; }
.mail-sidebar i {
  display: block;
  width: 34px;
  height: 34px;
  border-radius: 10px;
  background: rgba(255, 255, 255, .32);
  margin-bottom: 20px;
}
.mail-list { padding: 28px 22px; background: #fbfcff; border-right: 1px solid var(--line); }
.mail-list b {
  display: block;
  height: 54px;
  border-radius: 10px;
  background: #eef3fb;
  margin-bottom: 16px;
}
.mail-content { padding: 38px 34px; }
.mail-content strong {
  display: block;
  width: 72%;
  height: 26px;
  border-radius: 999px;
  background: #dfe7f5;
  margin-bottom: 34px;
}
.mail-content em {
  display: block;
  height: 16px;
  border-radius: 999px;
  background: #eef2f7;
  margin-bottom: 16px;
}
.mail-content em:nth-child(4) { width: 68%; }
.phone-card {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 210px;
  height: 300px;
  border-radius: 28px;
  background: #fff;
  box-shadow: var(--shadow);
  display: grid;
  place-items: center;
  border: 10px solid #f4f7fb;
}
.phone-card img { width: 132px; }

.section { padding: 96px 0; }
.soft-blue { background: var(--blue-soft); }
.centered { text-align: center; }
h2 {
  margin: 0;
  font-size: clamp(34px, 4vw, 48px);
  line-height: 1.35;
  font-weight: 700;
}
.section p, .download-hero p, .send-section p {
  margin: 22px auto 0;
  max-width: 760px;
  color: var(--muted);
  font-size: 18px;
}
.platform-scene {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 18px;
  margin-top: 64px;
}
.platform-scene article,
.download-row a,
.download-card {
  border-radius: 8px;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}
.platform-scene article {
  min-height: 156px;
  padding: 32px 18px;
  background: var(--dark);
  color: #fff;
  box-shadow: var(--shadow);
}
.platform-scene img { height: 48px; filter: drop-shadow(0 10px 18px rgba(75, 128, 254, .22)); }
.platform-scene span {
  display: block;
  margin-top: 20px;
  font-weight: 600;
}
.split-section {
  display: grid;
  grid-template-columns: .92fr 1.08fr;
  gap: 64px;
  align-items: center;
}
.split-section h2, .split-section p { text-align: left; margin-left: 0; }
.mail-cloud {
  min-height: 310px;
  position: relative;
  border-radius: 20px;
  background: linear-gradient(180deg, #f9fbff, #fff);
  box-shadow: var(--shadow);
}
.mail-cloud span {
  position: absolute;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 86px;
  min-height: 50px;
  padding: 0 18px;
  border-radius: 999px;
  background: #fff;
  color: #3b4657;
  font-weight: 700;
  box-shadow: 0 10px 28px rgba(44, 82, 130, .12);
}
.mail-cloud span:nth-child(1) { left: 12%; top: 16%; }
.mail-cloud span:nth-child(2) { right: 18%; top: 14%; }
.mail-cloud span:nth-child(3) { left: 38%; top: 39%; }
.mail-cloud span:nth-child(4) { left: 10%; bottom: 18%; }
.mail-cloud span:nth-child(5) { right: 9%; bottom: 24%; }
.mail-cloud span:nth-child(6) { right: 30%; bottom: 7%; }
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
  margin-top: 54px;
}
.feature-grid article {
  min-height: 190px;
  padding: 30px;
  background: #fff;
  border-radius: 8px;
  box-shadow: var(--shadow);
  text-align: left;
}
.feature-grid h3 {
  margin: 0 0 12px;
  font-size: 22px;
}
.feature-grid p {
  margin: 0;
  font-size: 16px;
}
.video-band {
  position: relative;
  background: var(--dark);
  color: #fff;
  overflow: hidden;
}
.video-band video {
  display: block;
  width: 100%;
  max-height: 640px;
  object-fit: cover;
  opacity: .72;
}
.video-title {
  position: absolute;
  inset: 0;
  display: grid;
  place-content: center;
  pointer-events: none;
  text-align: center;
}
.video-title h2 {
  font-size: clamp(32px, 5vw, 54px);
  text-shadow: 0 2px 4px rgba(0, 0, 0, .15);
}
.video-title p {
  margin: 16px 0 0;
  font-size: clamp(20px, 3vw, 28px);
}
.download-dark {
  padding: 44px 0 62px;
  background: var(--dark);
  color: #fff;
}
.download-dark h2 { font-size: clamp(30px, 4vw, 36px); }
.download-row {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 26px;
  margin-top: 40px;
}
.download-row a {
  min-height: 146px;
  border: 1px solid rgba(255, 255, 255, .62);
  display: grid;
  place-items: center;
  padding: 26px 10px 18px;
}
.download-row a:hover,
.download-card:hover {
  transform: translateY(-3px);
  background: rgba(255, 255, 255, .1);
}
.download-row img { height: 44px; }
.download-row span { display: block; font-size: 14px; }
.site-footer {
  background: var(--dark);
  color: #979797;
  border-top: 1px solid rgba(249, 249, 249, .1);
}
.site-footer.light {
  background: #fff;
  border-top: 1px solid rgba(0, 0, 0, .1);
}
.footer-inner {
  min-height: 84px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  font-size: 14px;
}
.footer-inner p { margin: 0; }
.footer-inner nav {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
}
.footer-inner a:hover { color: #fff; }
.site-footer.light a:hover { color: #333; }

.download-page { background: #fff; }
.download-hero {
  padding: 72px 0 42px;
  background: linear-gradient(180deg, #fff, var(--blue-soft));
}
.app-logo { margin-bottom: 22px; }
.download-hero h1 {
  margin: 0;
  font-size: clamp(38px, 5vw, 52px);
  line-height: 1.3;
}
.download-panel { padding: 48px 0 76px; }
.download-panel h2 {
  text-align: center;
  font-size: 32px;
  margin-bottom: 34px;
}
.download-cards {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 22px;
}
.download-card {
  min-height: 210px;
  padding: 26px 18px;
  background: var(--dark);
  color: #fff;
  text-align: center;
  display: grid;
  justify-items: center;
  align-content: center;
  gap: 12px;
  box-shadow: var(--shadow);
}
.download-card > img:not(.qr) { height: 45px; }
.download-card strong {
  display: block;
  font-size: 18px;
}
.download-card span {
  color: rgba(255, 255, 255, .78);
  font-size: 14px;
}
.qr-card {
  padding-top: 18px;
  gap: 8px;
}
.qr-card .qr {
  width: 104px;
  height: 104px;
  padding: 6px;
  background: #fff;
  border-radius: 6px;
}
.send-section {
  padding: 70px 0;
  background: var(--blue-soft);
}
.send-grid {
  display: grid;
  grid-template-columns: .9fr 1.1fr;
  gap: 54px;
  align-items: center;
}
.send-grid h2 { font-size: 36px; }
.send-grid h2, .send-grid p { text-align: left; margin-left: 0; }
.phone-form {
  background: #fff;
  border-radius: 8px;
  box-shadow: var(--shadow);
  padding: 30px;
}
.phone-form label {
  display: block;
  font-weight: 700;
  margin-bottom: 12px;
}
.phone-form div {
  display: flex;
  gap: 12px;
}
.phone-form input {
  min-width: 0;
  flex: 1;
  height: 52px;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0 16px;
  outline: none;
}
.phone-form input:focus {
  border-color: #4b80fe;
  box-shadow: 0 0 0 3px rgba(75, 128, 254, .18);
}
.phone-form button {
  width: 96px;
  min-height: 52px;
  border: 0;
  border-radius: 6px;
  background: #4b80fe;
  color: #fff;
  cursor: pointer;
}
.phone-form p {
  margin: 12px 0 0;
  font-size: 14px;
  color: var(--muted);
}

@media (max-width: 900px) {
  .site-header, .nav { height: 64px; }
  .nav-toggle { display: block; }
  .nav-links {
    position: fixed;
    left: 0;
    right: 0;
    top: 64px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 10px 20px 20px;
    background: #fff;
    box-shadow: 0 12px 26px rgba(0, 0, 0, .08);
  }
  .nav-links.open { display: flex; }
  .nav-links > a, .nav-group > a { display: block; padding: 14px 0; }
  .dropdown {
    position: static;
    display: block;
    transform: none;
    width: 100%;
    box-shadow: none;
    background: #f7f8fb;
  }
  .dropdown a { text-align: left; }
  .hero, .hero-grid { min-height: auto; }
  .hero-grid {
    grid-template-columns: 1fr;
    padding: 64px 0 58px;
  }
  .hero-device { min-height: 360px; }
  .mail-layout { grid-template-columns: 68px 1fr; }
  .mail-content { display: none; }
  .phone-card { width: 154px; height: 224px; }
  .section { padding: 68px 0; }
  .platform-scene,
  .feature-grid,
  .download-row,
  .download-cards,
  .split-section,
  .send-grid {
    grid-template-columns: 1fr;
  }
  .platform-scene { margin-top: 38px; }
  .split-section { gap: 34px; }
  .mail-cloud { min-height: 260px; }
  .video-title { position: static; padding: 38px 20px; background: var(--dark); }
  .video-band video { opacity: 1; }
  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
    padding: 22px 0;
  }
  .download-row { gap: 14px; }
}

@media (max-width: 520px) {
  .shell { width: min(100% - 28px, 1180px); }
  .hero-copy p, .section p, .download-hero p, .send-section p { font-size: 16px; }
  .mail-window { min-height: 310px; }
  .mail-layout { min-height: 262px; }
  .mail-sidebar { padding: 24px 16px; }
  .mail-list { padding: 22px 16px; }
  .phone-form div { flex-direction: column; }
  .phone-form button { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}