:root {
  color-scheme: dark;
  --ink: #f3f7f4;
  --muted: #aebbb4;
  --panel: rgba(11, 18, 20, 0.82);
  --panel-solid: #10181b;
  --line: rgba(255, 255, 255, 0.14);
  --track: #d8e1dc;
  --green: #2fd27e;
  --amber: #f0b342;
  --red: #f15d52;
  --steel: #6fa1b2;
  --blue: #8bd3ff;
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.34);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  background:
    linear-gradient(180deg, rgba(6, 9, 10, 0.22), #081012 620px),
    radial-gradient(circle at 84% 12%, rgba(47, 210, 126, 0.18), transparent 30%),
    linear-gradient(135deg, #121918 0%, #10161a 42%, #0b1214 100%);
  color: var(--ink);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  line-height: 1.5;
  letter-spacing: 0;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 24px;
  padding: 18px clamp(18px, 4vw, 56px);
  border-bottom: 1px solid var(--line);
  background: rgba(7, 13, 14, 0.88);
  backdrop-filter: blur(18px);
}

.brand,
.nav-links,
.hero-actions,
.site-footer {
  display: flex;
  align-items: center;
}

.brand {
  gap: 10px;
  font-weight: 800;
}

.brand-mark {
  width: 28px;
  height: 28px;
  border: 2px solid var(--track);
  border-radius: 50%;
  background:
    linear-gradient(90deg, transparent 43%, var(--green) 43% 57%, transparent 57%),
    linear-gradient(0deg, transparent 43%, var(--amber) 43% 57%, transparent 57%),
    #111b1d;
  box-shadow: 0 0 0 4px rgba(47, 210, 126, 0.12);
}

.nav-links {
  gap: 8px;
}

.nav-links a,
.header-action,
.primary-action,
.secondary-action {
  min-height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  font-weight: 700;
}

.nav-links a {
  padding: 0 12px;
  color: var(--muted);
}

.nav-links a:hover {
  color: var(--ink);
  background: rgba(255, 255, 255, 0.08);
}

.header-action {
  justify-self: end;
  padding: 0 14px;
  border: 1px solid var(--line);
  color: var(--ink);
}

.hero {
  min-height: calc(100svh - 72px);
  display: flex;
  align-items: center;
  padding: clamp(28px, 5vw, 64px) clamp(18px, 4vw, 56px);
}

.hero-panel {
  width: min(1260px, 100%);
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(320px, 0.86fr) minmax(440px, 1.14fr);
  gap: clamp(24px, 5vw, 72px);
  align-items: center;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--green);
  font-size: 0.78rem;
  font-weight: 900;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 20px;
  max-width: 9ch;
  font-size: clamp(4rem, 12vw, 9.8rem);
  line-height: 0.82;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 16px;
  max-width: 760px;
  font-size: clamp(2.1rem, 5vw, 4.8rem);
  line-height: 0.98;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 8px;
  font-size: 1.04rem;
}

.hero-text,
.section-copy p {
  max-width: 660px;
  color: var(--muted);
  font-size: clamp(1rem, 1.5vw, 1.2rem);
}

.hero-actions {
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.primary-action,
.secondary-action {
  padding: 0 18px;
}

.primary-action {
  background: var(--green);
  color: #06110c;
}

.secondary-action {
  border: 1px solid var(--line);
  color: var(--ink);
}

.control-board {
  position: relative;
  min-height: 410px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  overflow: hidden;
  background:
    linear-gradient(rgba(255, 255, 255, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.04) 1px, transparent 1px),
    #0a1011;
  background-size: 34px 34px;
  box-shadow: var(--shadow);
}

#railCanvas {
  width: 100%;
  height: 100%;
  min-height: 410px;
  display: block;
}

.board-status {
  position: absolute;
  left: 18px;
  right: 18px;
  bottom: 18px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(6, 10, 11, 0.82);
}

.board-status span {
  color: var(--muted);
}

.metrics,
.feature-band,
.split-band,
.scenario-band,
.site-footer {
  width: min(1260px, calc(100% - clamp(36px, 8vw, 112px)));
  margin: 0 auto;
}

.support-form {
  display: grid;
  gap: 10px;
  width: min(460px, 100%);
}

.support-form label {
  display: grid;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--muted);
}

.support-form input,
.support-form textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 10px 12px;
  background: rgba(12, 19, 21, 0.92);
  color: var(--ink);
  font: inherit;
  resize: vertical;
}

.support-form .primary-action {
  border: 0;
  cursor: pointer;
}

.metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.metrics div,
.feature-grid article,
.scenario-list article {
  background: rgba(12, 19, 21, 0.88);
}

.metrics div {
  padding: 22px;
}

.metrics strong,
.metrics span,
.scenario-list strong,
.scenario-list span,
.site-footer strong,
.site-footer span {
  display: block;
}

.metrics span,
.scenario-list span,
.site-footer span,
.feature-grid p {
  color: var(--muted);
}

.feature-band,
.scenario-band {
  padding: clamp(76px, 11vw, 142px) 0;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 34px;
}

.feature-grid article,
.scenario-list article {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 22px;
}

.feature-icon {
  width: 42px;
  height: 42px;
  display: block;
  margin-bottom: 22px;
  border-radius: 6px;
  border: 1px solid var(--line);
}

.signal-icon {
  background: radial-gradient(circle, var(--green) 0 18%, transparent 19%), #10181b;
}

.route-icon {
  background:
    linear-gradient(135deg, transparent 42%, var(--blue) 43% 57%, transparent 58%),
    #10181b;
}

.alert-icon {
  background:
    radial-gradient(circle at 50% 32%, var(--amber) 0 13%, transparent 14%),
    radial-gradient(circle at 50% 68%, var(--red) 0 13%, transparent 14%),
    #10181b;
}

.split-band {
  display: grid;
  grid-template-columns: 1fr 0.86fr;
  gap: clamp(26px, 6vw, 74px);
  align-items: center;
  padding: clamp(56px, 9vw, 110px) 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.schematic {
  position: relative;
  min-height: 360px;
  border-radius: 8px;
  background: #0b1113;
  border: 1px solid var(--line);
  overflow: hidden;
}

.track-line {
  position: absolute;
  height: 8px;
  border-radius: 999px;
  background: var(--track);
  box-shadow: 0 0 22px rgba(255, 255, 255, 0.18);
}

.track-line.main {
  left: 8%;
  right: 8%;
  top: 50%;
}

.track-line.branch-one {
  left: 36%;
  width: 46%;
  top: 36%;
  transform: rotate(-18deg);
  transform-origin: left center;
}

.track-line.branch-two {
  left: 28%;
  width: 52%;
  top: 63%;
  transform: rotate(18deg);
  transform-origin: left center;
}

.node {
  position: absolute;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 24px var(--green);
}

.n1 { left: 17%; top: 48%; }
.n2 { left: 36%; top: 48%; }
.n3 { left: 67%; top: 30%; }
.n4 { left: 78%; top: 60%; }

.train-chip {
  position: absolute;
  left: 48%;
  top: 43%;
  min-width: 88px;
  padding: 8px 10px;
  border-radius: 6px;
  background: var(--amber);
  color: #191004;
  font-weight: 900;
  text-align: center;
}

.scenario-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-top: 30px;
}

.site-footer {
  justify-content: space-between;
  gap: 24px;
  padding: 34px 0 48px;
  border-top: 1px solid var(--line);
}

@media (max-width: 920px) {
  .site-header {
    grid-template-columns: 1fr auto;
  }

  .nav-links {
    display: none;
  }

  .hero {
    min-height: auto;
  }

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

  h1 {
    max-width: 8ch;
  }

  .feature-grid,
  .metrics,
  .scenario-list {
    grid-template-columns: 1fr;
  }

  .control-board {
    min-height: 340px;
  }

  #railCanvas {
    min-height: 340px;
  }
}

@media (max-width: 560px) {
  .site-header {
    padding: 14px 16px;
  }

  .brand span:last-child {
    max-width: 132px;
    line-height: 1.05;
  }

  .header-action {
    padding: 0 10px;
    font-size: 0.9rem;
  }

  .board-status,
  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }
}