:root {
  color-scheme: light;
  --primary: #0b5bd3;
  --primary-hover: #0849ab;
  --ink: #172033;
  --muted: #5f697b;
  --line: #d9dee8;
  --surface: #ffffff;
  --soft: #f5f7fa;
  --green: #118a67;
  --green-soft: #e4f4ee;
  --content: 1180px;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 74px;
}

body {
  margin: 0;
  overflow-x: hidden;
  background: var(--surface);
  color: var(--ink);
  font-family: "Noto Sans SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.65;
}

body, button, a { letter-spacing: 0; }
a { color: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
img { display: block; max-width: 100%; }
h1, h2, h3, p, figure { margin-top: 0; }

.site-header {
  position: sticky;
  z-index: 30;
  top: 0;
  border-bottom: 1px solid rgba(217, 222, 232, .92);
  background: rgba(255, 255, 255, .96);
  backdrop-filter: blur(12px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  width: min(var(--content), calc(100% - 40px));
  min-height: 72px;
  margin: 0 auto;
}

.brand {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-size: 18px;
  font-weight: 800;
  line-height: 1;
  text-decoration: none;
}

.brand img, .footer-brand img { border-radius: 8px; }

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 34px;
  margin-left: auto;
}

.desktop-nav a {
  color: #4d5669;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
}

.desktop-nav a:hover { color: var(--primary); }

.download-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-height: 52px;
  padding: 12px 24px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: var(--primary);
  box-shadow: 0 8px 20px rgba(11, 91, 211, .18);
  color: #fff;
  font-size: 16px;
  font-weight: 800;
  line-height: 1.25;
  text-align: center;
  text-decoration: none;
  transition: background-color .16s ease, transform .16s ease, box-shadow .16s ease;
}

.download-button:hover {
  background: var(--primary-hover);
  box-shadow: 0 10px 24px rgba(11, 91, 211, .24);
}

.download-button:active { transform: translateY(1px); }

.header-download {
  min-height: 46px;
  padding: 10px 18px;
  font-size: 14px;
}

a:focus-visible,
button:focus-visible,
.screen-viewport:focus-visible {
  outline: 3px solid #78aaff;
  outline-offset: 3px;
}

.hero {
  position: relative;
  display: flex;
  min-height: min(680px, calc(100svh - 118px));
  align-items: center;
  overflow: hidden;
  background: #313b48 url("/assets/measure-room.jpg") center 58% / cover no-repeat;
  color: #fff;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: rgba(15, 22, 34, .48);
}

.hero-content {
  position: relative;
  z-index: 1;
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
  padding: 58px 0 74px;
}

.hero-kicker {
  margin-bottom: 10px;
  font-size: 15px;
  font-weight: 700;
}

.hero h1 {
  max-width: 720px;
  margin-bottom: 14px;
  font-size: clamp(46px, 5vw, 68px);
  line-height: 1.12;
}

.hero-summary {
  max-width: 680px;
  margin-bottom: 28px;
  font-size: clamp(20px, 2vw, 26px);
  font-weight: 600;
}

.hero-download { min-width: 238px; }

.release-meta {
  margin: 13px 0 0;
  color: rgba(255, 255, 255, .9);
  font-size: 13px;
}

.hero-next {
  position: absolute;
  z-index: 2;
  bottom: 12px;
  left: 50%;
  display: grid;
  width: 48px;
  height: 48px;
  place-items: center;
  transform: translateX(-50%);
  color: rgba(255, 255, 255, .88);
  font-size: 30px;
  line-height: 1;
  text-decoration: none;
}

.wechat-tip {
  width: min(var(--content), calc(100% - 40px));
  margin: 18px auto 0;
  padding: 12px 16px;
  border-left: 4px solid var(--primary);
  background: #eef4ff;
  color: #31405b;
  font-size: 14px;
}

.wechat-tip strong { margin-right: 8px; color: var(--ink); }
.section-band { padding: 82px 0; }

.section-inner {
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
}

.section-heading { margin-bottom: 42px; }

.centered-heading {
  max-width: 720px;
  margin-right: auto;
  margin-left: auto;
  text-align: center;
}

.eyebrow {
  margin-bottom: 6px;
  color: var(--primary);
  font-size: 13px;
  font-weight: 800;
}

.section-heading h2,
.privacy-layout h2,
.final-download h2 {
  margin-bottom: 10px;
  font-size: clamp(28px, 3vw, 40px);
  line-height: 1.3;
}

.section-heading > p:last-child,
.feature-item p,
.privacy-layout p,
.install-steps p,
.final-download p { color: var(--muted); }

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.feature-item {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr);
  gap: 18px;
  min-width: 0;
  padding: 34px 30px;
}

.feature-item + .feature-item { border-left: 1px solid var(--line); }

.feature-icon {
  display: grid;
  width: 52px;
  height: 52px;
  place-items: center;
  border: 1px solid #cfe0fb;
  border-radius: 8px;
  background: #edf4ff;
  color: var(--primary);
  font: 800 25px/1 "Segoe UI", sans-serif;
}

.feature-item h3,
.install-steps h3 {
  margin: 1px 0 7px;
  font-size: 20px;
  line-height: 1.4;
}

.feature-item p,
.install-steps p { margin-bottom: 0; font-size: 15px; }

.screens {
  overflow: hidden;
  border-top: 1px solid var(--line);
  background: var(--soft);
}

.screen-viewport { overflow: visible; }

.screen-track {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 42px;
}

.screen-slide { min-width: 0; margin: 0; text-align: center; }

.phone-frame {
  width: min(100%, 294px);
  margin: 0 auto;
  overflow: hidden;
  border: 1px solid #cfd6e2;
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 16px 36px rgba(23, 32, 51, .12);
}

.phone-frame img {
  width: 100%;
  aspect-ratio: 9 / 20;
  object-fit: cover;
  object-position: top center;
}

.screen-slide figcaption { display: grid; gap: 3px; margin-top: 18px; }
.screen-slide figcaption strong { font-size: 19px; }
.screen-slide figcaption span { color: var(--muted); font-size: 14px; }
.carousel-controls { display: none; }

.privacy-band {
  padding: 56px 0;
  border-top: 1px solid #bfe5d7;
  border-bottom: 1px solid #bfe5d7;
  background: var(--green-soft);
}

.privacy-layout {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  align-items: center;
  gap: 24px;
}

.privacy-icon {
  display: grid;
  width: 56px;
  height: 56px;
  place-items: center;
  border: 2px solid var(--green);
  border-radius: 50%;
  color: var(--green);
  font-size: 27px;
  font-weight: 800;
}

.privacy-layout .eyebrow,
.privacy-layout h2 { color: #0b7659; }
.privacy-layout h2 { margin-bottom: 5px; }
.privacy-layout p:last-child { margin-bottom: 0; color: #326b5a; }

.install-steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 32px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.install-steps li {
  position: relative;
  display: grid;
  grid-template-columns: 52px minmax(0, 1fr);
  gap: 18px;
  min-width: 0;
}

.install-steps li + li::before {
  position: absolute;
  top: 25px;
  right: calc(100% + 8px);
  width: 16px;
  height: 1px;
  background: var(--line);
  content: "";
}

.step-number {
  display: grid;
  width: 50px;
  height: 50px;
  place-items: center;
  border: 2px solid var(--primary);
  border-radius: 50%;
  color: var(--primary);
  font-size: 20px;
  font-weight: 800;
}

.install-note {
  margin: 32px 0 0;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}

.final-download {
  padding: 68px 0;
  border-top: 1px solid var(--line);
  background: var(--soft);
  text-align: center;
}

.final-download p { margin-bottom: 24px; }

.final-download small {
  display: block;
  margin-top: 12px;
  color: var(--muted);
}

footer {
  padding: 42px 20px 28px;
  background: var(--ink);
  color: #fff;
}

.footer-inner {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 32px;
  width: min(var(--content), 100%);
  margin: 0 auto;
}

.footer-brand { display: flex; gap: 12px; align-items: center; }
.footer-brand strong { font-size: 17px; }
.footer-brand p { margin: 4px 0 0; color: #b8c2d2; font-size: 13px; }
.footer-inner nav { display: flex; flex-wrap: wrap; gap: 24px; }

.footer-inner a,
.icp { color: #dce3ee; font-size: 14px; text-decoration: none; }

.icp,
.copyright {
  display: block;
  width: max-content;
  max-width: 100%;
  margin-right: auto;
  margin-left: auto;
  color: #909bad;
  font-size: 12px;
  text-align: center;
}

.icp { margin-top: 28px; text-decoration: none; }
.copyright { margin-top: 5px; margin-bottom: 0; }

@media (max-width: 820px) {
  html { scroll-padding-top: 62px; }

  .header-inner {
    width: calc(100% - 28px);
    min-height: 62px;
    gap: 10px;
  }

  .brand { min-width: 0; gap: 8px; font-size: 16px; }
  .brand img { width: 36px; height: 36px; }
  .desktop-nav { display: none; }
  .header-download { min-height: 44px; padding: 9px 12px; font-size: 13px; }
  .header-download span { display: none; }

  .hero {
    min-height: min(680px, calc(100svh - 110px));
    background-position: 61% center;
  }

  .hero-overlay { background: rgba(15, 22, 34, .54); }

  .hero-content {
    width: calc(100% - 40px);
    padding: 54px 0 76px;
    text-align: center;
  }

  .hero-kicker { font-size: 13px; }
  .hero h1 { font-size: 39px; }

  .hero-summary {
    max-width: 320px;
    margin-right: auto;
    margin-left: auto;
    font-size: 18px;
  }

  .hero-download { width: min(100%, 330px); }
  .release-meta { font-size: 12px; }
  .wechat-tip { width: calc(100% - 28px); font-size: 13px; }
  .wechat-tip strong, .wechat-tip span { display: block; }
  .section-band { padding: 58px 0; }
  .section-inner { width: calc(100% - 40px); }
  .section-heading { margin-bottom: 30px; }

  .section-heading h2,
  .privacy-layout h2,
  .final-download h2 { font-size: 28px; }

  .feature-grid { grid-template-columns: 1fr; }
  .feature-item { padding: 24px 0; }
  .feature-item + .feature-item { border-top: 1px solid var(--line); border-left: 0; }

  .screen-viewport {
    overflow-x: auto;
    overscroll-behavior-x: contain;
    scroll-behavior: smooth;
    scroll-snap-type: x mandatory;
    scrollbar-width: none;
  }

  .screen-viewport::-webkit-scrollbar { display: none; }

  .screen-track {
    display: flex;
    width: 300%;
    gap: 0;
  }

  .screen-slide {
    flex: 0 0 33.333333%;
    width: 33.333333%;
    padding: 0;
    scroll-snap-align: start;
    scroll-snap-stop: always;
  }

  .phone-frame { width: min(78vw, 304px); }
  .screen-slide figcaption { padding: 0 12px; }

  .carousel-controls {
    display: grid;
    grid-template-columns: 48px auto 48px;
    align-items: center;
    justify-content: center;
    gap: 18px;
    margin-top: 22px;
  }

  .carousel-arrow {
    display: grid;
    width: 48px;
    height: 48px;
    place-items: center;
    border: 1px solid var(--line);
    border-radius: 50%;
    background: #fff;
    color: var(--ink);
    font: 400 30px/1 "Segoe UI", sans-serif;
    cursor: pointer;
  }

  .carousel-dots { display: flex; gap: 9px; }

  .carousel-dot {
    width: 10px;
    height: 10px;
    padding: 0;
    border: 0;
    border-radius: 50%;
    background: #c9d0dc;
    cursor: pointer;
  }

  .carousel-dot.is-active { background: var(--primary); }
  .privacy-band { padding: 42px 0; }

  .privacy-layout {
    grid-template-columns: 44px minmax(0, 1fr);
    align-items: start;
    gap: 15px;
  }

  .privacy-icon { width: 42px; height: 42px; font-size: 20px; }
  .install-steps { grid-template-columns: 1fr; gap: 26px; }
  .install-steps li + li::before { display: none; }
  .install-note { text-align: left; }
  .final-download { padding: 54px 0; }
  .footer-inner { flex-direction: column; }
}

@media (max-width: 360px) {
  .header-inner { width: calc(100% - 20px); }
  .brand { font-size: 15px; }
  .brand img { width: 32px; height: 32px; }
  .header-download { padding-right: 10px; padding-left: 10px; font-size: 12px; }
  .hero-content, .section-inner { width: calc(100% - 28px); }
  .hero h1 { font-size: 36px; }
  .hero-summary { font-size: 17px; }
  .release-meta { font-size: 11px; }

  .feature-item {
    grid-template-columns: 46px minmax(0, 1fr);
    gap: 14px;
  }

  .feature-icon { width: 44px; height: 44px; }
  .phone-frame { width: min(82vw, 284px); }
  .footer-brand p { overflow-wrap: anywhere; }
}

@media (prefers-reduced-motion: reduce) {
  html, .screen-viewport { scroll-behavior: auto; }
  .download-button { transition: none; }
}