:root {
  --bg: #f3f4f2;
  --panel: #fcfcfb;
  --text: #151a1f;
  --muted: #4d5966;
  --line: #c8ced4;
  --accent: #3f6574;
  --focus: #26424f;
  --max-width: 76rem;
  --space-2xs: 0.35rem;
  --space-xs: 0.65rem;
  --space-sm: 0.95rem;
  --space-md: 1.4rem;
  --space-lg: 2.2rem;
  --space-xl: 3.4rem;
  --space-2xl: 5.1rem;
  --radius-sm: 0.45rem;
  --radius-md: 0.8rem;
  --radius-lg: 1.2rem;
  --shadow-soft: 0 18px 34px -28px rgba(16, 23, 31, 0.42);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "IBM Plex Sans", "Segoe UI", Arial, sans-serif;
  color: var(--text);
  background-color: var(--bg);
  line-height: 1.58;
  text-rendering: optimizeLegibility;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background-image: radial-gradient(rgba(34, 52, 65, 0.06) 0.8px, transparent 0.8px);
  background-size: 14px 14px;
  opacity: 0.42;
  pointer-events: none;
  z-index: -2;
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  background: linear-gradient(180deg, rgba(243, 244, 242, 0.82), rgba(243, 244, 242, 0.95));
  pointer-events: none;
  z-index: -1;
}

h1,
h2,
h3 {
  font-family: "Space Grotesk", "Avenir Next", "Segoe UI", sans-serif;
  line-height: 1.18;
  letter-spacing: -0.02em;
  margin: 0;
}

h1 {
  font-size: clamp(2.1rem, 4.4vw, 3.7rem);
}

h2 {
  font-size: clamp(1.6rem, 3.1vw, 2.2rem);
  margin-bottom: var(--space-md);
}

h3 {
  font-size: clamp(1.05rem, 2.1vw, 1.28rem);
  margin-bottom: var(--space-xs);
}

p {
  margin: 0 0 var(--space-md);
  max-width: 72ch;
}

a {
  color: inherit;
  text-underline-offset: 0.2em;
}

a:hover {
  text-decoration-thickness: 2px;
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  top: -120px;
  left: var(--space-md);
  z-index: 1200;
  padding: var(--space-xs) var(--space-sm);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  color: var(--text);
  text-decoration: none;
}

.skip-link:focus {
  top: var(--space-sm);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  border-bottom: 1px solid rgba(91, 106, 118, 0.25);
  background: rgba(243, 244, 242, 0.92);
  backdrop-filter: blur(9px);
}

.header-inner {
  width: min(100% - 2rem, var(--max-width));
  margin-inline: auto;
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-sm) 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  text-decoration: none;
  color: var(--text);
}

.brand-mark {
  width: 1.15rem;
  height: 1.15rem;
  border: 1px solid var(--accent);
  transform: rotate(45deg);
  border-radius: 2px;
  position: relative;
}

.brand-mark::before {
  content: "";
  position: absolute;
  inset: 0.25rem;
  border: 1px solid rgba(63, 101, 116, 0.56);
}

.brand-text {
  font-family: "Space Grotesk", "Avenir Next", sans-serif;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.nav-toggle {
  margin-left: auto;
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.75rem;
  font: inherit;
  color: var(--text);
}

.site-nav {
  width: 100%;
  display: none;
}

.site-nav ul {
  list-style: none;
  margin: var(--space-sm) 0 0;
  padding: 0;
  display: grid;
  gap: var(--space-2xs);
}

.site-nav a {
  display: block;
  padding: 0.3rem 0.45rem;
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--muted);
  font-size: 0.94rem;
}

.site-nav a.is-active {
  background: rgba(63, 101, 116, 0.12);
  color: var(--text);
}

.site-header.nav-open .site-nav {
  display: block;
}

main {
  width: min(100% - 2rem, var(--max-width));
  margin-inline: auto;
  padding: var(--space-2xl) 0 var(--space-xl);
}

.section {
  padding-block: var(--space-xl);
  border-top: 1px solid rgba(104, 117, 129, 0.25);
}

.section:first-of-type {
  border-top: 0;
  padding-top: var(--space-lg);
}

.hero {
  display: grid;
  gap: var(--space-lg);
  align-items: start;
  border: 1px solid rgba(102, 118, 130, 0.3);
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(252, 252, 251, 0.96), rgba(246, 247, 245, 0.9));
  box-shadow: var(--shadow-soft);
  padding: clamp(1.1rem, 3vw, 2.2rem);
}

.eyebrow {
  display: inline-block;
  margin-bottom: var(--space-sm);
  padding: 0.2rem 0.58rem;
  border: 1px solid rgba(63, 101, 116, 0.45);
  border-radius: 99px;
  text-transform: uppercase;
  font-size: 0.74rem;
  letter-spacing: 0.08em;
  color: var(--accent);
  font-weight: 600;
}

.hero-subtitle {
  font-size: clamp(1.08rem, 2vw, 1.38rem);
  max-width: 46ch;
}

.hero-note {
  color: var(--muted);
  font-size: 1.01rem;
}

.hero-diagram {
  margin: 0;
  border: 1px solid rgba(101, 116, 127, 0.35);
  background: rgba(247, 248, 246, 0.72);
  border-radius: var(--radius-md);
  padding: var(--space-sm);
}

.hero-diagram svg {
  width: 100%;
  height: auto;
}

.hero-diagram figcaption {
  margin-top: var(--space-xs);
  color: var(--muted);
  font-size: 0.89rem;
}

.grid-lines path {
  fill: none;
  stroke: rgba(96, 113, 126, 0.3);
  stroke-width: 1;
}

.module-boxes polygon,
.terminal-sketch polygon,
.terminal-sketch polyline,
.terminal-sketch line,
.terminal-sketch circle {
  fill: rgba(63, 101, 116, 0.08);
  stroke: rgba(47, 70, 82, 0.9);
  stroke-width: 1.4;
  vector-effect: non-scaling-stroke;
}

.signal-lines path {
  fill: none;
  stroke: url(#lineFade);
  stroke-width: 2.1;
}

.node-points circle {
  fill: var(--accent);
}

.section-panel {
  background: rgba(251, 251, 250, 0.88);
  border: 1px solid rgba(102, 118, 130, 0.28);
  border-radius: var(--radius-md);
  padding: clamp(1rem, 2.4vw, 1.55rem);
  box-shadow: var(--shadow-soft);
}

.statement-list,
.wedge-list,
.reference-list {
  margin: 0;
  padding-left: 1.2rem;
}

.statement-list li,
.wedge-list li,
.reference-list li {
  margin-bottom: var(--space-xs);
}

.grid-two {
  display: grid;
  gap: var(--space-md);
  grid-template-columns: 1fr;
}

.panel {
  border: 1px solid rgba(102, 118, 130, 0.3);
  border-radius: var(--radius-md);
  background: rgba(252, 252, 251, 0.86);
  padding: var(--space-md);
}

.closing-line {
  margin-bottom: 0;
  color: var(--muted);
}

.section-intro {
  color: var(--muted);
}

.layer-stack {
  margin-top: var(--space-md);
  display: grid;
  gap: var(--space-sm);
}

.layer-card {
  position: relative;
  border: 1px solid rgba(88, 105, 117, 0.34);
  background: rgba(251, 251, 250, 0.9);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-md) var(--space-md) calc(var(--space-md) + 1.8rem);
  box-shadow: var(--shadow-soft);
}

.layer-card::before {
  content: "";
  position: absolute;
  left: 1rem;
  top: 0.92rem;
  width: 0.32rem;
  height: calc(100% - 1.8rem);
  background: rgba(63, 101, 116, 0.18);
}

.layer-index {
  display: inline-block;
  font-family: "Space Grotesk", sans-serif;
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: var(--space-xs);
}

.terminal-sketch {
  margin: 0;
  border: 1px solid rgba(102, 118, 130, 0.3);
  border-radius: var(--radius-md);
  background: rgba(250, 251, 249, 0.9);
  padding: var(--space-sm);
}

.terminal-sketch svg {
  width: 100%;
  height: auto;
}

.terminal-sketch figcaption {
  margin-top: var(--space-xs);
  font-size: 0.87rem;
  color: var(--muted);
}

.questions-grid {
  display: grid;
  gap: var(--space-sm);
  grid-template-columns: 1fr;
}

.question-card {
  border: 1px solid rgba(100, 115, 126, 0.34);
  border-radius: var(--radius-sm);
  background: rgba(249, 250, 248, 0.86);
  padding: var(--space-sm);
}

.reference-list a,
.archive-card {
  color: var(--text);
}

.archive-grid {
  display: grid;
  gap: var(--space-sm);
  grid-template-columns: 1fr;
}

.archive-card {
  border: 1px solid rgba(95, 111, 122, 0.34);
  border-radius: var(--radius-sm);
  background: rgba(252, 252, 251, 0.92);
  padding: var(--space-sm);
  text-decoration: none;
}

.archive-card:hover {
  border-color: rgba(63, 101, 116, 0.58);
}

.archive-card.placeholder {
  color: var(--muted);
  border-style: dashed;
}

.site-footer {
  width: min(100% - 2rem, var(--max-width));
  margin-inline: auto;
  border-top: 1px solid rgba(104, 117, 129, 0.25);
  padding: var(--space-md) 0 var(--space-xl);
  color: var(--muted);
  font-size: 0.93rem;
}

[data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 500ms ease, transform 500ms ease;
}

[data-reveal].revealed {
  opacity: 1;
  transform: translateY(0);
}

@media (min-width: 48rem) {
  .nav-toggle {
    display: none;
  }

  .site-nav {
    margin-left: auto;
    width: auto;
    display: block;
  }

  .site-nav ul {
    margin: 0;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: flex-end;
    gap: 0.15rem;
  }

  .site-nav a {
    font-size: 0.85rem;
    white-space: nowrap;
  }

  .hero {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  }

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

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

@media (min-width: 72rem) {
  .questions-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

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

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

  [data-reveal] {
    opacity: 1;
    transform: none;
  }
}