:root {
  color-scheme: light;
  --bg: #f6f8fb;
  --ink: #17202a;
  --muted: #5b6776;
  --line: #dce4ee;
  --panel: #ffffff;
  --panel-2: #edf6f3;
  --green: #1f8a70;
  --blue: #255c99;
  --orange: #d97828;
  --dark: #111827;
  --shadow: 0 20px 50px rgba(23, 32, 42, 0.09);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  line-height: 1.55;
}

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

.hero {
  min-height: 92vh;
  padding: 24px clamp(18px, 4vw, 64px) 56px;
  background:
    linear-gradient(135deg, rgba(31, 138, 112, 0.12), transparent 42%),
    linear-gradient(315deg, rgba(37, 92, 153, 0.14), transparent 48%),
    #f9fbfd;
  border-bottom: 1px solid var(--line);
}

.nav {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  max-width: 1180px;
  margin: 0 auto;
  flex-wrap: wrap;
}

.nav a {
  min-height: 40px;
  display: inline-flex;
  align-items: center;
  padding: 8px 13px;
  border: 1px solid rgba(23, 32, 42, 0.1);
  border-radius: 8px;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.65);
  font-size: 14px;
}

.hero-grid {
  max-width: 1180px;
  min-height: calc(92vh - 92px);
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.95fr);
  gap: clamp(30px, 6vw, 74px);
  align-items: center;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--green);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  max-width: 780px;
  font-size: clamp(42px, 6.2vw, 80px);
  line-height: 0.98;
  letter-spacing: 0;
}

h2 {
  margin: 0;
  font-size: clamp(30px, 4vw, 48px);
  line-height: 1.08;
  letter-spacing: 0;
}

h3 {
  margin: 0 0 10px;
  font-size: 20px;
  line-height: 1.2;
}

.lead {
  max-width: 680px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: clamp(18px, 2vw, 22px);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.button {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 18px;
  border-radius: 8px;
  font-weight: 750;
  border: 1px solid transparent;
}

.button.primary {
  background: var(--dark);
  color: #fff;
}

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

.signal-panel {
  padding: 24px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid rgba(23, 32, 42, 0.1);
  box-shadow: var(--shadow);
}

.node-card {
  padding: 22px;
  border-radius: 8px;
  background: var(--dark);
  color: #fff;
}

.node-card.gateway {
  background: #fff;
  color: var(--ink);
  border: 1px solid var(--line);
}

.node-card strong {
  display: block;
  margin: 10px 0;
  font-size: 22px;
  line-height: 1.2;
}

.node-card p {
  margin: 0;
  color: inherit;
  opacity: 0.78;
}

.chip {
  display: inline-flex;
  padding: 5px 9px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.16);
  color: inherit;
  font-size: 12px;
  font-weight: 800;
}

.gateway .chip {
  background: var(--panel-2);
  color: var(--green);
}

.radio-line {
  height: 86px;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 13px;
}

.radio-line span {
  width: 12px;
  height: 12px;
  border-radius: 999px;
  background: var(--orange);
  box-shadow: 0 0 0 8px rgba(217, 120, 40, 0.12);
}

.mini-metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-top: 14px;
}

.mini-metrics div {
  min-height: 78px;
  padding: 14px;
  border-radius: 8px;
  background: #eef3f8;
}

.mini-metrics b,
.mini-metrics span {
  display: block;
}

.mini-metrics span {
  margin-top: 4px;
  color: var(--muted);
  font-size: 13px;
}

.section {
  padding: clamp(58px, 8vw, 104px) clamp(18px, 4vw, 64px);
}

.section.muted {
  background: #fff;
  border-block: 1px solid var(--line);
}

.section-heading {
  max-width: 760px;
  margin: 0 auto 34px;
  text-align: center;
}

.section-heading p:not(.eyebrow) {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 18px;
}

.architecture-grid,
.roles-grid {
  max-width: 1180px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.card,
.roles-grid article,
.hardware-card,
.connection {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 10px 28px rgba(23, 32, 42, 0.05);
}

.card {
  min-height: 260px;
  padding: 22px;
}

.number {
  display: inline-flex;
  margin-bottom: 34px;
  color: var(--blue);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-weight: 800;
}

.card p,
.roles-grid p,
.hardware-card li,
.connection p,
.timeline p {
  color: var(--muted);
}

.flow {
  max-width: 1240px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(7, minmax(118px, 1fr));
  align-items: stretch;
  gap: 8px;
}

.flow-step {
  min-height: 220px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fbfd;
}

.flow-step span {
  width: 34px;
  height: 34px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
  border-radius: 50%;
  background: var(--green);
  color: #fff;
  font-weight: 800;
}

.flow-step strong {
  display: block;
  font-size: 17px;
}

.connector {
  display: none;
}

.hardware-layout {
  max-width: 980px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.hardware-card {
  padding: 26px;
}

.hardware-card.accent {
  background: #f3faf7;
}

.hardware-card ul {
  margin: 18px 0 0;
  padding-left: 20px;
}

.hardware-card li + li {
  margin-top: 10px;
}

.connection-grid {
  max-width: 1080px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.connection {
  min-height: 158px;
  padding: 20px;
}

.connection strong {
  display: block;
  margin-bottom: 9px;
  color: var(--blue);
}

.timeline {
  max-width: 900px;
  margin: 0 auto;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.timeline li {
  display: grid;
  grid-template-columns: 112px 1fr;
  gap: 18px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.timeline li > span {
  color: var(--orange);
  font-weight: 850;
}

.timeline p {
  margin: 0;
}

.roles-grid {
  grid-template-columns: repeat(4, 1fr);
}

.roles-grid article {
  min-height: 184px;
  padding: 20px;
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 28px clamp(18px, 4vw, 64px);
  background: var(--dark);
  color: #fff;
}

.footer span {
  color: rgba(255, 255, 255, 0.68);
}

@media (max-width: 1020px) {
  .hero-grid {
    grid-template-columns: 1fr;
    padding-top: 52px;
  }

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

  .flow {
    grid-template-columns: 1fr;
    max-width: 620px;
  }

  .flow-step {
    min-height: auto;
  }

  .connector {
    display: block;
    width: 2px;
    height: 22px;
    margin: 0 auto;
    background: var(--line);
  }

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

@media (max-width: 680px) {
  .hero {
    min-height: auto;
    padding-top: 14px;
  }

  .nav {
    justify-content: flex-start;
  }

  .nav a {
    font-size: 13px;
    padding-inline: 10px;
  }

  .hero-grid {
    min-height: auto;
    padding-top: 42px;
  }

  h1 {
    font-size: 40px;
  }

  .hero-actions,
  .footer {
    flex-direction: column;
  }

  .button {
    width: 100%;
  }

  .signal-panel {
    padding: 16px;
  }

  .mini-metrics,
  .architecture-grid,
  .hardware-layout,
  .connection-grid,
  .roles-grid {
    grid-template-columns: 1fr;
  }

  .timeline li {
    grid-template-columns: 1fr;
    gap: 8px;
  }
}