/* ═══ PARALLAX ENGINEERING — design system ═══
   Palette: void navy · electric cyan · hot magenta · solar gold
   Type: Instrument Serif (display) · Space Grotesk (text) · JetBrains Mono (data)
*/

:root {
  --void: #05060f;
  --void-2: #0a0c1c;
  --ink: #e8e9f2;
  --ink-dim: #9a9db6;
  --cyan: #4ef0ff;
  --magenta: #ff4ecd;
  --gold: #ffc94e;
  --violet: #8b6cff;
  --line: rgba(139, 108, 255, 0.18);
  --serif: "Instrument Serif", Georgia, serif;
  --sans: "Space Grotesk", system-ui, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  background: var(--void);
  color: var(--ink);
  font-family: var(--sans);
  font-weight: 300;
  line-height: 1.65;
  overflow-x: hidden;
}

::selection { background: var(--magenta); color: var(--void); }

a { color: var(--cyan); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ── ambient layers ── */
#hero-field {
  position: fixed; inset: 0;
  width: 100vw; height: 100vh;
  z-index: 0;
  opacity: 0.85;
}
.grain {
  position: fixed; inset: -50%;
  z-index: 2; pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='300' height='300' filter='url(%23n)' opacity='0.5'/%3E%3C/svg%3E");
  opacity: 0.05;
  animation: grain 0.6s steps(4) infinite;
}
@keyframes grain {
  0% { transform: translate(0,0); } 25% { transform: translate(-2%,3%); }
  50% { transform: translate(3%,-2%); } 75% { transform: translate(-3%,-3%); }
  100% { transform: translate(2%,2%); }
}

nav, header, main, footer { position: relative; z-index: 3; }

/* ── nav ── */
#nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 10;
  display: flex; justify-content: space-between; align-items: center;
  padding: 1.1rem 2.5rem;
  background: linear-gradient(to bottom, rgba(5,6,15,0.92), rgba(5,6,15,0));
  backdrop-filter: blur(2px);
}
.wordmark {
  font-family: var(--mono); font-weight: 600; font-size: 0.85rem;
  letter-spacing: 0.35em; color: var(--ink);
}
.wordmark span { display: block; font-weight: 300; color: var(--violet); letter-spacing: 0.42em; font-size: 0.6rem; }
.wordmark:hover { text-decoration: none; }
.nav-links { display: flex; gap: 1.6rem; }
.nav-links a {
  font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.12em;
  color: var(--ink-dim); text-transform: uppercase;
}
.nav-links a:hover { color: var(--cyan); text-decoration: none; }
@media (max-width: 900px) { .nav-links { display: none; } }

/* ── hero ── */
.hero {
  min-height: 100vh;
  display: flex; flex-direction: column; justify-content: center;
  padding: 8rem 8vw 6rem;
  max-width: 1200px;
}
.kicker {
  font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.3em;
  text-transform: uppercase; color: var(--gold);
  margin-bottom: 2rem;
}
.hero h1 {
  font-family: var(--serif); font-weight: 400;
  font-size: clamp(3.2rem, 9vw, 7.5rem);
  line-height: 0.98; letter-spacing: -0.01em;
  margin-bottom: 3rem;
}
.hero h1 em {
  font-style: italic;
  background: linear-gradient(100deg, var(--cyan), var(--violet) 45%, var(--magenta));
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
}
.lede {
  max-width: 620px; font-size: 1.12rem; color: var(--ink-dim);
  margin-bottom: 1.4rem;
}
.lede strong { color: var(--ink); font-weight: 500; }
.lede em { color: var(--cyan); font-style: italic; }
.lede.small { font-size: 0.95rem; }
.scroll-cue {
  margin-top: 3rem; font-family: var(--mono); font-size: 0.72rem;
  letter-spacing: 0.25em; text-transform: uppercase; color: var(--violet);
  animation: bob 2.4s ease-in-out infinite;
  width: fit-content;
}
@keyframes bob { 0%,100% { transform: translateY(0); } 50% { transform: translateY(8px); } }

/* ── propositions ── */
.prop {
  padding: 9rem 8vw;
  border-top: 1px solid var(--line);
  background: linear-gradient(to bottom, rgba(10,12,28,0.75), rgba(5,6,15,0.55));
  transition: opacity 0.9s ease, transform 0.9s ease;
}
/* screenshot-test mode */
body.capture .hero { min-height: auto; padding-top: 10rem; }

/* hidden state applies only once JS is confirmed running */
body.anim .prop { opacity: 0; transform: translateY(40px); }
body.anim .prop.vis { opacity: 1; transform: none; }

.prop-num {
  font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.35em;
  text-transform: uppercase; color: var(--magenta);
}
.prop-head h2 {
  font-family: var(--serif); font-weight: 400;
  font-size: clamp(2.2rem, 5vw, 4rem); line-height: 1.05;
  margin: 0.8rem 0 3.5rem;
}
.prop-body {
  display: grid; grid-template-columns: minmax(320px, 1fr) minmax(320px, 1fr);
  gap: 4rem; align-items: start;
}
.prop-body.reverse { direction: rtl; }
.prop-body.reverse > * { direction: ltr; }
@media (max-width: 1000px) {
  .prop-body, .prop-body.reverse { grid-template-columns: 1fr; direction: ltr; }
}

.prose p { margin-bottom: 1.3rem; color: var(--ink-dim); font-size: 1.02rem; }
.prose strong { color: var(--ink); font-weight: 500; }
.prose em { color: var(--cyan); }
.math-block {
  margin: 1.6rem 0; padding: 1.1rem 1.4rem;
  border-left: 2px solid var(--violet);
  background: rgba(139,108,255,0.06);
  border-radius: 0 8px 8px 0;
  overflow-x: auto;
  color: var(--ink);
}
.katex { font-size: 1.05em; }

/* ── figures ── */
.fig { margin: 0; }
.fig canvas {
  width: 100%; height: auto; display: block;
  border: 1px solid var(--line); border-radius: 12px;
  background: var(--void-2);
  box-shadow: 0 0 80px rgba(139,108,255,0.10), inset 0 0 60px rgba(0,0,0,0.5);
  touch-action: none;
}
.fig figcaption {
  margin-top: 0.9rem; font-family: var(--mono);
  font-size: 0.72rem; line-height: 1.6; color: var(--ink-dim);
  letter-spacing: 0.03em;
}

/* ── controls ── */
.controls { margin-top: 2rem; display: flex; flex-direction: column; gap: 0.9rem; }
.btn-row { display: flex; flex-wrap: wrap; gap: 0.55rem; }
button {
  font-family: var(--mono); font-size: 0.75rem; letter-spacing: 0.08em;
  padding: 0.6rem 1.1rem;
  background: rgba(139,108,255,0.08);
  color: var(--ink); border: 1px solid var(--line); border-radius: 8px;
  cursor: pointer; transition: all 0.18s ease;
}
button:hover { border-color: var(--violet); background: rgba(139,108,255,0.18); transform: translateY(-1px); }
button:active { transform: translateY(0); }
button.accent {
  border-color: var(--cyan); color: var(--cyan);
  background: rgba(78,240,255,0.07);
  box-shadow: 0 0 20px rgba(78,240,255,0.12);
}
button.accent:hover { background: rgba(78,240,255,0.16); }
button.toggle.on { border-color: var(--gold); color: var(--gold); background: rgba(255,201,78,0.08); }
button b { font-weight: 600; }

.slider-row {
  display: flex; align-items: center; gap: 1rem;
  font-family: var(--mono); font-size: 0.75rem; color: var(--ink-dim);
}
.slider-row .mono { color: var(--cyan); min-width: 5.5ch; }
input[type="range"] {
  flex: 1; appearance: none; -webkit-appearance: none; height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--magenta));
  border-radius: 2px; outline: none;
}
input[type="range"]::-webkit-slider-thumb {
  appearance: none; -webkit-appearance: none;
  width: 16px; height: 16px; border-radius: 50%;
  background: var(--ink); border: 2px solid var(--violet);
  cursor: grab; box-shadow: 0 0 12px rgba(139,108,255,0.6);
}
input[type="range"]::-moz-range-thumb {
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--ink); border: 2px solid var(--violet); cursor: grab;
}

.readout {
  font-family: var(--mono); font-size: 0.78rem; line-height: 1.8;
  color: var(--ink-dim); white-space: pre-wrap;
  padding: 0.8rem 1rem; border: 1px dashed var(--line); border-radius: 8px;
  min-height: 2.2rem;
  background: rgba(5,6,15,0.5);
}
.readout .hot { color: var(--magenta); }
.readout .cool { color: var(--cyan); }
.readout .warm { color: var(--gold); }
.mono { font-family: var(--mono); }

/* ── colophon ── */
.colophon {
  padding: 8rem 8vw 6rem;
  border-top: 1px solid var(--line);
  background: linear-gradient(to bottom, rgba(10,12,28,0.8), var(--void));
  max-width: 100%;
}
.colophon h2 {
  font-family: var(--serif); font-weight: 400; font-style: italic;
  font-size: clamp(2rem, 4.5vw, 3.4rem); margin-bottom: 1.6rem;
  background: linear-gradient(100deg, var(--gold), var(--magenta));
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
  width: fit-content;
}
.colophon p { max-width: 680px; color: var(--ink-dim); margin-bottom: 1.4rem; }
.colophon .small { font-size: 0.72rem; letter-spacing: 0.04em; line-height: 2; }