:root {
  color-scheme: dark;
  --night: #0a0d10;
  --iron: #13181d;
  --steel: #242c33;
  --fog: #9aa6af;
  --paper: #eef2f4;
  --signal: #ff6a24;
  --trace: #4bd5b4;
  --body-copy: #b5bec5;
  --footer-copy: #7f8a92;
  --grid-line: rgba(255, 255, 255, 0.022);
  --shell-line: rgba(255, 255, 255, 0.07);
  --line: rgba(255, 255, 255, 0.1);
  --line-strong: rgba(255, 255, 255, 0.16);
  --shell-sheen: rgba(255, 255, 255, 0.02);
  --signal-wash: rgba(255, 106, 36, 0.1);
  --signal-glow: rgba(255, 106, 36, 0.3);
  --trace-glow: rgba(75, 213, 180, 0.45);
  --pulse-halo: rgba(75, 213, 180, 0.1);
  --packet-bg: rgba(10, 13, 16, 0.82);
  --panel-shadow: rgba(0, 0, 0, 0.28);
  --display: "Arial Narrow", "Aptos Display", "Helvetica Neue", sans-serif;
  --body: "Aptos", "Helvetica Neue", Arial, sans-serif;
  --utility: "SFMono-Regular", "Cascadia Code", "Liberation Mono", monospace;
}

html[data-theme="light"] {
  color-scheme: light;
  --night: #eef2f5;
  --iron: #ffffff;
  --steel: #dce4e9;
  --fog: #66737c;
  --paper: #17232c;
  --signal: #e85c19;
  --trace: #087f69;
  --body-copy: #52616c;
  --footer-copy: #6f7c85;
  --grid-line: rgba(32, 53, 67, 0.045);
  --shell-line: rgba(32, 53, 67, 0.12);
  --line: rgba(32, 53, 67, 0.14);
  --line-strong: rgba(32, 53, 67, 0.2);
  --shell-sheen: rgba(255, 255, 255, 0.58);
  --signal-wash: rgba(232, 92, 25, 0.09);
  --signal-glow: rgba(232, 92, 25, 0.2);
  --trace-glow: rgba(8, 127, 105, 0.28);
  --pulse-halo: rgba(8, 127, 105, 0.13);
  --packet-bg: rgba(255, 255, 255, 0.9);
  --panel-shadow: rgba(39, 57, 68, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  background: var(--night);
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  color: var(--paper);
  background:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px),
    var(--night);
  background-size: 56px 56px;
  font-family: var(--body);
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
}

a:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 6px;
}

.page-shell {
  width: min(1440px, 100%);
  min-height: 100vh;
  margin: 0 auto;
  padding: 0 clamp(24px, 5vw, 78px);
  border-inline: 1px solid var(--shell-line);
  background: linear-gradient(115deg, var(--shell-sheen), transparent 46%);
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 104px;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  gap: 14px;
  align-items: center;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-content: center;
  gap: 4px;
  width: 46px;
  height: 46px;
  border: 1px solid var(--line-strong);
  border-radius: 11px;
  background: var(--iron);
  transform: rotate(-3deg);
}

.brand-mark i {
  display: block;
  width: 20px;
  height: 3px;
  background: var(--paper);
}

.brand-mark i:nth-child(2) {
  width: 15px;
  background: var(--signal);
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font: 700 20px/1 var(--display);
  letter-spacing: 0.14em;
}

.brand small,
.build-state,
.eyebrow,
.field-label,
.principle-key,
footer {
  font-family: var(--utility);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.brand small {
  margin-top: 5px;
  color: var(--fog);
  font-size: 9px;
}

.build-state {
  display: flex;
  gap: 10px;
  align-items: center;
  color: var(--fog);
  font-size: 10px;
}

.header-actions {
  display: flex;
  gap: 16px;
  align-items: center;
}

.theme-toggle {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  min-height: 34px;
  padding: 0 11px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--fog);
  background: var(--iron);
  font: 9px/1 var(--utility);
  letter-spacing: 0.08em;
  cursor: pointer;
}

.theme-toggle:hover {
  color: var(--paper);
  border-color: var(--line-strong);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 3px;
}

.theme-toggle-icon::before {
  content: "☼";
  display: block;
  font-size: 15px;
  line-height: 1;
}

html[data-theme="light"] .theme-toggle-icon::before {
  content: "◐";
}

.state-pulse {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--trace);
  box-shadow: 0 0 0 5px var(--pulse-halo);
  animation: breathe 2.8s ease-in-out infinite;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.88fr) minmax(480px, 1.12fr);
  gap: clamp(50px, 8vw, 128px);
  align-items: center;
  min-height: 650px;
  padding: 88px 0 82px;
}

.hero-copy {
  max-width: 620px;
}

.eyebrow {
  margin: 0 0 26px;
  color: var(--signal);
  font-size: 10px;
}

h1 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(54px, 5.2vw, 80px);
  font-stretch: condensed;
  font-weight: 650;
  line-height: 0.96;
  letter-spacing: -0.055em;
}

h1 span {
  display: block;
  white-space: nowrap;
}

.hero-intro {
  max-width: 560px;
  margin: 34px 0 0;
  color: var(--body-copy);
  font-size: clamp(15px, 1.35vw, 18px);
  line-height: 1.8;
}

.status-line {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 20px;
  align-items: baseline;
  margin-top: 38px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.status-line span {
  color: var(--fog);
  font: 10px/1 var(--utility);
  letter-spacing: 0.08em;
}

.status-line strong {
  font-size: 13px;
  font-weight: 600;
}

.signal-field {
  position: relative;
  min-height: 440px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 20px;
  background:
    radial-gradient(circle at 72% 35%, var(--signal-wash), transparent 30%),
    var(--iron);
  box-shadow: 0 34px 80px var(--panel-shadow);
}

.field-label {
  display: flex;
  justify-content: space-between;
  padding: 18px 20px;
  border-bottom: 1px solid var(--line);
  color: var(--fog);
  font-size: 9px;
}

.signal-rail {
  position: relative;
  height: 260px;
  margin: 0 28px;
}

.rail-line {
  position: absolute;
  top: 51%;
  right: 5%;
  left: 5%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--trace) 15%, var(--signal) 74%, transparent);
  box-shadow: 0 0 20px var(--signal-glow);
}

.node {
  position: absolute;
  top: calc(51% - 6px);
  width: 13px;
  height: 13px;
  border: 2px solid var(--iron);
  border-radius: 50%;
  background: var(--trace);
  box-shadow: 0 0 0 1px var(--trace), 0 0 18px var(--trace-glow);
}

.node-a { left: 10%; }
.node-b { left: 38%; }
.node-c { left: 65%; background: var(--signal); box-shadow: 0 0 0 1px var(--signal), 0 0 18px var(--signal-glow); }
.node-d { right: 9%; background: var(--paper); box-shadow: 0 0 0 1px var(--paper); }

.signal-packet {
  position: absolute;
  padding: 7px 9px;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--fog);
  background: var(--packet-bg);
  font: 8px/1 var(--utility);
  letter-spacing: 0.08em;
}

.packet-a { top: 62px; left: 17%; }
.packet-b { right: 24%; bottom: 52px; }
.packet-c { top: 72px; right: 7%; color: var(--signal); }

.field-readout {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line);
}

.field-readout div {
  display: grid;
  min-width: 0;
  padding: 20px;
  border-right: 1px solid var(--line);
}

.field-readout div:last-child {
  border-right: 0;
}

.field-readout span,
.field-readout small {
  color: var(--fog);
  font: 9px/1 var(--utility);
}

.field-readout strong {
  margin: 24px 0 7px;
  font-size: 13px;
  font-weight: 600;
}

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

.principles article {
  min-height: 220px;
  padding: 36px clamp(20px, 3vw, 42px) 40px 0;
  border-right: 1px solid var(--line);
}

.principles article + article {
  padding-left: clamp(20px, 3vw, 42px);
}

.principles article:last-child {
  border-right: 0;
}

.principle-key {
  color: var(--signal);
  font-size: 9px;
}

.principles h2 {
  margin: 28px 0 13px;
  font-family: var(--display);
  font-size: 24px;
  font-weight: 650;
  letter-spacing: -0.025em;
}

.principles p {
  max-width: 320px;
  margin: 0;
  color: var(--fog);
  font-size: 13px;
  line-height: 1.75;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 32px 0 44px;
  color: var(--footer-copy);
  font-size: 9px;
}

@keyframes breathe {
  50% { opacity: 0.45; transform: scale(0.82); }
}

@media (max-width: 980px) {
  .hero {
    grid-template-columns: 1fr;
    gap: 64px;
    padding-top: 72px;
  }

  .signal-field {
    min-height: 420px;
  }
}

@media (max-width: 720px) {
  .page-shell {
    padding-inline: 20px;
    border-inline: 0;
  }

  .site-header {
    min-height: 88px;
  }

  .brand small {
    display: none;
  }

  .build-state {
    font-size: 8px;
  }

  .hero {
    min-height: auto;
    padding: 64px 0;
  }

  h1 {
    font-size: clamp(42px, 12vw, 60px);
  }

  .signal-field {
    min-height: 390px;
    border-radius: 14px;
  }

  .signal-rail {
    height: 230px;
    margin-inline: 12px;
  }

  .field-readout strong {
    margin-top: 16px;
    font-size: 11px;
  }

  .field-readout div {
    padding: 15px 10px;
  }

  .principles {
    grid-template-columns: 1fr;
  }

  .principles article,
  .principles article + article {
    min-height: 0;
    padding: 30px 0 34px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .principles article:last-child {
    border-bottom: 0;
  }

  footer {
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}