:root {
  --green: #07c160;
  --green-dark: #059c4c;
  --green-soft: #eaf8f0;
  --ink: #171a1f;
  --muted: #6b7280;
  --line: #e5e7eb;
  --soft: #f6f7f8;
  --white: #fff;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--white);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
button { font: inherit; }
img { display: block; max-width: 100%; height: auto; }

.site-header {
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 28px;
  border-bottom: 1px solid var(--line);
}
.brand { display: inline-flex; align-items: center; gap: 10px; font-size: 19px; font-weight: 700; }
.brand img { width: 34px; height: 34px; border-radius: 8px; }
.brand.small { font-size: 16px; }
.brand.small img { width: 28px; height: 28px; }
.header-note { color: var(--muted); font-size: 13px; }
.site-nav { display: flex; align-items: center; gap: 26px; margin-left: auto; margin-right: 26px; color: #4b5563; font-size: 13px; }
.site-nav a:hover { color: var(--green-dark); }
.site-nav .nav-download { min-height: 34px; display: inline-flex; align-items: center; padding: 0 14px; border-radius: 6px; color: #fff; background: var(--green); font-weight: 700; }

.download-hero {
  width: min(1180px, 100%);
  min-height: 650px;
  margin: 0 auto;
  padding: 66px 28px 58px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(380px, .8fr);
  align-items: center;
  gap: 80px;
}
.download-copy { min-width: 0; }
.eyebrow, .section-head > span { color: var(--green-dark); font-size: 12px; font-weight: 750; }
h1, h2, p { margin-top: 0; }
h1 { margin-bottom: 18px; font-size: 52px; line-height: 1.08; letter-spacing: 0; }
.lead { max-width: 580px; margin-bottom: 30px; color: #4b5563; font-size: 18px; line-height: 1.75; }

.primary-download { max-width: 430px; }
.primary-button {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 0 20px;
  border-radius: 8px;
  color: #fff;
  background: var(--green);
  box-shadow: 0 12px 28px rgba(7,193,96,.2);
  font-size: 17px;
  font-weight: 700;
}
.primary-button:hover { background: var(--green-dark); }
.primary-button small { font-size: 12px; font-weight: 600; opacity: .8; }
.primary-download p { margin: 9px 0 0; color: var(--muted); font-size: 12px; }

.alternate-downloads { max-width: 560px; margin-top: 28px; border-top: 1px solid var(--line); }
.alternate-item {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}
.alternate-item > div:first-child { display: grid; gap: 3px; }
.alternate-item strong { font-size: 14px; }
.alternate-item span { color: var(--muted); font-size: 12px; }
.alternate-item a, .alternate-item button {
  min-height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 12px;
  border: 1px solid #cdd3d8;
  border-radius: 6px;
  color: #374151;
  background: #fff;
  cursor: pointer;
  font-size: 13px;
  font-weight: 650;
}
.alternate-item a:hover, .alternate-item button:hover { border-color: var(--green); color: var(--green-dark); }
.alternate-actions { display: flex; gap: 8px; }
.alternate-actions b { margin-left: 5px; color: var(--green-dark); }

.product-preview { position: relative; min-height: 520px; }
.phone {
  position: absolute;
  margin: 0;
  overflow: hidden;
  border: 8px solid #16191d;
  border-radius: 30px;
  background: var(--soft);
  box-shadow: 0 24px 60px rgba(17,24,39,.16);
}
.phone img { width: 100%; height: 100%; object-fit: cover; object-position: top; }
.phone-main { top: 0; right: 20px; width: 260px; aspect-ratio: 9 / 19.5; z-index: 2; }
.phone-side { left: 0; bottom: 0; width: 220px; aspect-ratio: 9 / 19.5; opacity: .92; }

.proof-band {
  display: grid;
  grid-template-columns: repeat(3, minmax(0,1fr));
  width: min(1124px, calc(100% - 56px));
  margin: 0 auto;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.proof-band div { display: grid; gap: 5px; padding: 24px; border-right: 1px solid var(--line); }
.proof-band div:last-child { border-right: 0; }
.proof-band strong { font-size: 14px; }
.proof-band span { color: var(--muted); font-size: 12px; line-height: 1.5; }

.positioning {
  width: min(1124px, calc(100% - 56px));
  margin: 0 auto;
  padding: 110px 0 70px;
  display: grid;
  grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr);
  gap: 90px;
}
.section-label, .story-copy > span, .boundaries > div:first-child > span { color: var(--green-dark); font-size: 12px; font-weight: 750; }
.positioning h2, .story-copy h2, .boundaries h2 { margin: 10px 0 0; font-size: 40px; line-height: 1.28; letter-spacing: 0; }
.positioning-body { padding-top: 25px; }
.positioning-body p { color: #4b5563; font-size: 16px; line-height: 1.85; }

.capabilities { width: min(1124px, calc(100% - 56px)); margin: 0 auto 110px; display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); border-top: 1px solid var(--line); border-left: 1px solid var(--line); }
.capabilities article { min-height: 230px; display: grid; grid-template-columns: 36px minmax(0,1fr); gap: 15px; padding: 28px 24px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.capabilities article > b { color: var(--green-dark); font-size: 12px; }
.capabilities h3 { margin: 0 0 12px; font-size: 19px; }
.capabilities p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.75; }

.feature-story { width: 100%; min-height: 720px; display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); align-items: center; background: var(--soft); }
.feature-social { background: #fff; }
.story-media { height: 720px; overflow: hidden; background: #eef0f1; }
.story-media img { width: 100%; height: 100%; object-fit: cover; object-position: top center; }
.story-copy { max-width: 560px; padding: 70px 72px; }
.story-copy p { margin: 22px 0; color: #4b5563; font-size: 16px; line-height: 1.8; }
.story-copy ul { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--line); }
.story-copy li { padding: 13px 0; border-bottom: 1px solid var(--line); font-size: 14px; }

.screens, .install-guide, .faq { width: min(1124px, calc(100% - 56px)); margin: 0 auto; padding: 90px 0; }
.section-head { margin-bottom: 28px; }
.section-head h2 { margin: 8px 0 0; font-size: 34px; letter-spacing: 0; }
.screen-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 24px; }
.screen-grid figure { margin: 0; min-width: 0; }
.screen-grid img { width: 100%; aspect-ratio: 9 / 16; object-fit: cover; object-position: top; border: 1px solid var(--line); border-radius: 8px; background: var(--soft); }
.screen-grid figcaption { padding-top: 10px; color: var(--muted); font-size: 13px; }

.use-scenes { width: min(1124px, calc(100% - 56px)); margin: 0 auto; padding: 20px 0 100px; }
.scene-list { border-top: 1px solid var(--line); }
.scene-list article { display: grid; grid-template-columns: 180px minmax(240px,.7fr) minmax(300px,1fr); gap: 30px; align-items: baseline; padding: 26px 0; border-bottom: 1px solid var(--line); }
.scene-list span { color: var(--green-dark); font-size: 12px; font-weight: 700; }
.scene-list h3 { margin: 0; font-size: 18px; }
.scene-list p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.7; }

.install-guide { width: 100%; max-width: none; padding-left: max(28px, calc((100vw - 1124px)/2)); padding-right: max(28px, calc((100vw - 1124px)/2)); background: var(--soft); }
.install-guide ol { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 1px; margin: 0; padding: 0; list-style: none; background: var(--line); border: 1px solid var(--line); }
.install-guide li { min-height: 128px; display: flex; gap: 15px; padding: 22px; background: #fff; }
.install-guide li > b { width: 30px; height: 30px; flex: 0 0 auto; display: grid; place-items: center; border-radius: 50%; color: #fff; background: var(--green); }
.install-guide li div { display: grid; align-content: start; gap: 8px; }
.install-guide li span { color: var(--muted); font-size: 13px; line-height: 1.6; }

.boundaries { width: min(1124px, calc(100% - 56px)); margin: 0 auto; padding: 90px 0; display: grid; grid-template-columns: minmax(0,.65fr) minmax(0,1.35fr); gap: 80px; border-bottom: 1px solid var(--line); }
.boundary-points { display: grid; gap: 0; border-top: 1px solid var(--line); }
.boundary-points p { display: grid; grid-template-columns: 110px minmax(0,1fr); gap: 20px; margin: 0; padding: 18px 0; border-bottom: 1px solid var(--line); color: var(--muted); font-size: 14px; line-height: 1.7; }
.boundary-points b { color: var(--ink); }

.faq details { border-top: 1px solid var(--line); padding: 18px 0; }
.faq details:last-child { border-bottom: 1px solid var(--line); }
.faq summary { cursor: pointer; font-size: 15px; font-weight: 700; }
.faq details p { margin: 10px 0 0; color: var(--muted); font-size: 14px; line-height: 1.7; }
.site-footer { min-height: 92px; display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 24px max(28px, calc((100vw - 1124px)/2)); border-top: 1px solid var(--line); }
.site-footer p { margin: 0; color: var(--muted); font-size: 12px; }
.site-footer .beian a { color: var(--muted); text-decoration: none; }
.site-footer .beian a:hover { text-decoration: underline; }

@media (max-width: 900px) {
  .site-nav { display: none; }
  .download-hero { grid-template-columns: 1fr; gap: 54px; padding-top: 46px; }
  .primary-download, .alternate-downloads { max-width: none; }
  .product-preview { min-height: 580px; width: min(430px, 100%); margin: 0 auto; }
  .phone-main { right: 0; }
  .phone-side { left: 0; }
  .proof-band { grid-template-columns: 1fr; }
  .proof-band div { border-right: 0; border-bottom: 1px solid var(--line); }
  .proof-band div:last-child { border-bottom: 0; }
  .positioning { grid-template-columns: 1fr; gap: 20px; }
  .positioning-body { padding-top: 0; }
  .capabilities { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .feature-story { grid-template-columns: 1fr; }
  .feature-social .story-copy { order: 2; }
  .story-media { height: 620px; }
  .story-copy { max-width: none; }
  .scene-list article { grid-template-columns: 130px minmax(0,1fr); }
  .scene-list p { grid-column: 2; }
  .boundaries { grid-template-columns: 1fr; gap: 30px; }
}

@media (max-width: 620px) {
  .site-header { height: 58px; padding: 0 18px; }
  .brand { font-size: 17px; }
  .brand img { width: 31px; height: 31px; }
  .download-hero { min-height: 0; padding: 38px 18px 52px; }
  h1 { font-size: 38px; }
  .lead { font-size: 16px; margin-bottom: 24px; }
  .primary-button { min-height: 58px; }
  .alternate-item, .alternate-actions { align-items: stretch; flex-direction: column; }
  .alternate-actions { width: 100%; }
  .alternate-actions a, .alternate-actions button, .developer-item > a { width: 100%; }
  .product-preview { min-height: 460px; }
  .phone-main { width: 220px; }
  .phone-side { width: 180px; }
  .proof-band, .screens, .faq { width: calc(100% - 36px); }
  .positioning, .capabilities, .use-scenes, .boundaries { width: calc(100% - 36px); }
  .positioning { padding: 72px 0 48px; }
  .positioning h2, .story-copy h2, .boundaries h2 { font-size: 30px; }
  .capabilities { grid-template-columns: 1fr; margin-bottom: 72px; }
  .capabilities article { min-height: 0; }
  .story-media { height: 520px; }
  .story-copy { padding: 54px 18px; }
  .screens, .faq { padding: 64px 0; }
  .screen-grid { grid-template-columns: repeat(3, minmax(230px,1fr)); gap: 12px; overflow-x: auto; padding-bottom: 8px; scroll-snap-type: x mandatory; }
  .screen-grid figure { scroll-snap-align: start; }
  .section-head h2 { font-size: 28px; }
  .install-guide { padding: 64px 18px; }
  .install-guide ol { grid-template-columns: 1fr; }
  .install-guide li { min-height: 0; }
  .use-scenes { padding: 0 0 72px; }
  .scene-list article { grid-template-columns: 1fr; gap: 8px; }
  .scene-list p { grid-column: auto; }
  .boundaries { padding: 64px 0; }
  .boundary-points p { grid-template-columns: 1fr; gap: 6px; }
  .site-footer { align-items: flex-start; flex-direction: column; padding: 24px 18px; }
}