:root {
  --ink: #101318;
  --ink-2: #2d3440;
  --muted: #66717f;
  --line: #d9dee6;
  --soft: #f3f6f9;
  --panel: #ffffff;
  --graphite: #1b1f25;
  --steel: #8793a2;
  --cyan: #0b86c6;
  --cyan-2: #17a9d4;
  --green: #16a368;
  --yellow: #d7921f;
  --red: #d84a4a;
  --shadow: 0 18px 48px rgba(16, 19, 24, .12);
  --radius: 8px;
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-size: 16px;
  line-height: 1.7;
}

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

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, .94);
  border-bottom: 1px solid rgba(217, 222, 230, .82);
  backdrop-filter: blur(12px);
}

.nav {
  width: min(1180px, calc(100% - 36px));
  margin: 0 auto;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-weight: 800;
  color: var(--ink);
  letter-spacing: 0;
}

.brand img {
  width: 42px;
  height: 42px;
  border-radius: 8px;
  box-shadow: 0 8px 24px rgba(16, 19, 24, .16);
}

.brand span {
  font-size: 20px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  color: var(--ink-2);
  font-size: 14px;
}

.nav-links a {
  padding: 10px 12px;
  border-radius: 6px;
}

.nav-links a:hover,
.nav-links a[aria-current="page"] {
  background: var(--soft);
  color: var(--cyan);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: 7px;
  font-weight: 700;
  font-size: 15px;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease, border-color .18s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  color: #fff;
  background: var(--cyan);
  box-shadow: 0 12px 26px rgba(11, 134, 198, .26);
}

.btn-primary:hover {
  background: #0877b0;
}

.btn-secondary {
  color: var(--ink);
  background: #fff;
  border-color: var(--line);
}

.btn-secondary:hover {
  border-color: var(--cyan);
}

.section {
  padding: 84px 0;
}

.section-tight {
  padding: 56px 0;
}

.wrap {
  width: min(1180px, calc(100% - 36px));
  margin: 0 auto;
}

.hero {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(135deg, #ffffff 0%, #f7fafc 42%, #e9f4f9 100%);
  padding: 48px 0 30px;
}

.hero::after {
  content: "";
  position: absolute;
  inset: auto -8% -34% 42%;
  height: 420px;
  background: radial-gradient(circle, rgba(23, 169, 212, .14), rgba(23, 169, 212, 0) 68%);
  pointer-events: none;
}

.hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(420px, 560px);
  align-items: center;
  gap: 52px;
}

.hero h1,
.page-hero h1 {
  margin: 0;
  max-width: 720px;
  color: var(--ink);
  font-size: clamp(40px, 6vw, 66px);
  line-height: 1.08;
  letter-spacing: 0;
}

.hero p,
.page-hero p {
  margin: 22px 0 0;
  max-width: 640px;
  color: var(--muted);
  font-size: 18px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.hero-facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 24px;
}

.fact {
  padding: 14px 16px;
  border: 1px solid rgba(217, 222, 230, .9);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, .74);
}

.fact strong {
  display: block;
  color: var(--ink);
  font-size: 18px;
  line-height: 1.2;
}

.fact span {
  display: block;
  margin-top: 5px;
  color: var(--muted);
  font-size: 13px;
}

.dashboard {
  border-radius: 8px;
  background: #151a20;
  color: #edf3f7;
  box-shadow: var(--shadow);
  border: 1px solid rgba(255, 255, 255, .08);
  overflow: hidden;
}

.dash-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 18px;
  border-bottom: 1px solid rgba(255, 255, 255, .08);
}

.window-dots {
  display: flex;
  gap: 7px;
}

.window-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #4a535f;
}

.window-dots span:nth-child(1) { background: #d84a4a; }
.window-dots span:nth-child(2) { background: #d7921f; }
.window-dots span:nth-child(3) { background: #16a368; }

.dash-title {
  color: #aeb9c5;
  font-size: 13px;
}

.dash-body {
  padding: 16px;
}

.sensor-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.sensor {
  min-height: 118px;
  padding: 16px;
  border-radius: 7px;
  background: #20262e;
  border: 1px solid rgba(255, 255, 255, .07);
}

.sensor-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: #aeb9c5;
  font-size: 13px;
}

.sensor-value {
  margin-top: 12px;
  font-size: 34px;
  font-weight: 800;
  line-height: 1;
}

.sensor-value small {
  font-size: 15px;
  color: #aeb9c5;
}

.bar {
  height: 8px;
  margin-top: 18px;
  border-radius: 999px;
  background: #333c47;
  overflow: hidden;
}

.bar span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--cyan-2), var(--green));
}

.bar.warn span {
  background: linear-gradient(90deg, var(--yellow), var(--red));
}

.dash-log {
  margin-top: 12px;
  padding: 14px 16px;
  border-radius: 7px;
  background: #0f141a;
  color: #aeb9c5;
  font-size: 13px;
}

.dash-log div + div {
  margin-top: 6px;
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 32px;
  margin-bottom: 34px;
}

.section-head h2,
.content h2 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(28px, 4vw, 42px);
  line-height: 1.18;
  letter-spacing: 0;
}

.section-head p {
  margin: 0;
  max-width: 560px;
  color: var(--muted);
}

.feature-grid,
.scenario-grid,
.review-grid,
.download-grid,
.faq-grid {
  display: grid;
  gap: 18px;
}

.feature-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.scenario-grid,
.review-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.split .review-grid {
  grid-template-columns: 1fr;
}

.download-grid {
  grid-template-columns: 1.2fr .8fr;
  align-items: stretch;
}

.faq-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.card,
.panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.card {
  padding: 24px;
}

.card h3,
.panel h3 {
  margin: 0;
  color: var(--ink);
  font-size: 20px;
  line-height: 1.35;
}

.card p,
.panel p,
.content p,
.content li {
  color: var(--muted);
}

.icon {
  width: 42px;
  height: 42px;
  display: inline-grid;
  place-items: center;
  margin-bottom: 18px;
  border-radius: 8px;
  background: #eaf6fb;
  color: var(--cyan);
}

.band {
  background: var(--soft);
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(360px, 500px);
  gap: 42px;
  align-items: center;
}

.mini-board {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: 0 16px 34px rgba(16, 19, 24, .08);
}

.step {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 14px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.step:last-child {
  border-bottom: 0;
}

.step b {
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 7px;
  background: var(--graphite);
  color: #fff;
}

.step h3 {
  margin: 0;
  font-size: 18px;
}

.step p {
  margin: 4px 0 0;
  color: var(--muted);
}

.quote {
  position: relative;
}

.quote p {
  margin: 0;
}

.quote strong {
  display: block;
  margin-top: 20px;
  color: var(--ink);
}

.page-hero {
  background: linear-gradient(135deg, #f8fafc, #eef6fa);
  padding: 68px 0;
  border-bottom: 1px solid var(--line);
}

.breadcrumbs {
  margin-bottom: 18px;
  color: var(--muted);
  font-size: 14px;
}

.breadcrumbs a {
  color: var(--cyan);
}

.content {
  max-width: 900px;
}

.content h2 {
  margin-top: 44px;
}

.content h2:first-child {
  margin-top: 0;
}

.content ul {
  padding-left: 20px;
}

.callout {
  padding: 22px;
  border-left: 4px solid var(--cyan);
  background: #eef8fc;
  border-radius: 0 8px 8px 0;
}

.download-panel {
  padding: 30px;
}

.download-panel .version {
  display: inline-flex;
  padding: 6px 10px;
  border-radius: 6px;
  background: #eaf6fb;
  color: var(--cyan);
  font-weight: 800;
  font-size: 14px;
}

.source-list {
  display: grid;
  gap: 12px;
  margin-top: 24px;
}

.source-list a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 7px;
  color: var(--ink);
  background: #fff;
}

.source-list a span {
  color: var(--muted);
  font-size: 14px;
}

.history-list {
  display: grid;
  gap: 14px;
}

.history-item {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 18px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.history-item:last-child {
  border-bottom: 0;
}

.history-version {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 72px;
  height: 38px;
  border-radius: 7px;
  background: var(--graphite);
  color: #fff;
  font-weight: 800;
}

.history-item h3 {
  margin: 0;
  font-size: 20px;
}

.history-item p {
  margin: 6px 0 0;
  color: var(--muted);
}

.site-footer {
  background: #101318;
  color: #d7dde5;
  padding: 44px 0 26px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.2fr repeat(2, minmax(0, .7fr));
  gap: 28px;
}

.site-footer h2,
.site-footer h3 {
  margin: 0 0 12px;
  color: #fff;
}

.site-footer p,
.site-footer a {
  color: #aeb9c5;
  font-size: 14px;
}

.footer-links {
  display: grid;
  gap: 8px;
}

.copyright {
  margin-top: 32px;
  padding-top: 18px;
  border-top: 1px solid rgba(255, 255, 255, .12);
  color: #8b96a3;
  font-size: 13px;
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 18px;
  background: rgba(16, 19, 24, .62);
}

.modal.is-open {
  display: flex;
}

.modal-box {
  width: min(760px, 100%);
  max-height: min(92vh, 760px);
  overflow: auto;
  background: #fff;
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 22px 24px;
  border-bottom: 1px solid var(--line);
}

.modal-head h2 {
  margin: 0;
  font-size: 24px;
}

.modal-close {
  width: 38px;
  height: 38px;
  border: 0;
  border-radius: 7px;
  background: var(--soft);
  color: var(--ink);
  font-size: 26px;
  line-height: 1;
  cursor: pointer;
}

.modal-body {
  padding: 24px;
}

.qr-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  margin-top: 18px;
}

.qr-card {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  text-align: center;
}

.qr-card img {
  width: 178px;
  height: 178px;
  margin: 0 auto 12px;
}

.qr-card strong {
  display: block;
}

.qr-card span {
  color: var(--muted);
  font-size: 13px;
}

.modal-note {
  margin-top: 18px;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 920px) {
  .nav {
    height: auto;
    padding: 14px 0;
    align-items: flex-start;
  }

  .nav-links {
    display: none;
  }

  .hero-grid,
  .split,
  .download-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 52px;
  }

  .feature-grid,
  .scenario-grid,
  .review-grid,
  .faq-grid,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .section-head {
    display: block;
  }

  .section-head p {
    margin-top: 12px;
  }
}

@media (max-width: 640px) {
  .wrap,
  .nav {
    width: min(100% - 28px, 1180px);
  }

  .brand span {
    font-size: 18px;
  }

  .nav-actions .btn-secondary {
    display: none;
  }

  .hero h1,
  .page-hero h1 {
    font-size: 38px;
  }

  .hero-facts,
  .sensor-grid,
  .qr-grid,
  .history-item {
    grid-template-columns: 1fr;
  }

  .section {
    padding: 60px 0;
  }

  .card,
  .download-panel {
    padding: 20px;
  }
}