/* style.css — Tufte meets Turing */

/* ── Reset & base ─────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --void:    #09090b;
  --surface: #111113;
  --dim:     #2a2a2e;
  --muted:   #6b6b72;
  --text:    #e8e6e0;
  --warm:    #f0ead8;
  --accent:  #c8a96e;
  --font:    "Georgia", "Times New Roman", serif;
  --mono:    "Menlo", "Consolas", "Liberation Mono", monospace;
}

html, body {
  height: 100%;
  background: var(--void);
  color: var(--text);
  font-family: var(--font);
  font-size: clamp(15px, 1.1vw, 18px);
  line-height: 1.65;
  overflow-x: hidden;
}

/* ── Background canvas ────────────────────────────────────── */
#bg {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0.18;
  transition: opacity 0.8s ease;
  image-rendering: pixelated;
  z-index: 0;
  /* Slow breathing radial behind the sim */
  background: radial-gradient(ellipse 80% 60% at 50% 40%,
    #1a1408 0%, var(--void) 100%);
  animation: breathe 12s ease-in-out infinite alternate;
}

@keyframes breathe {
  from { opacity: 0.15; }
  to   { opacity: 0.22; }
}

/* ── SVG grain overlay ────────────────────────────────────── */
#grain {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 1;
}

/* ── Switcher nav ─────────────────────────────────────────── */
#switcher {
  position: fixed;
  top: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 0;
  z-index: 10;
  border: 1px solid var(--dim);
  border-radius: 3px;
  overflow: hidden;
  background: rgba(9,9,11,0.7);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

#switcher .domain {
  background: transparent;
  border: none;
  border-right: 1px solid var(--dim);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  padding: 0.45rem 0.9rem;
  cursor: pointer;
  transition: color 0.2s, background 0.2s;
  white-space: nowrap;
}

#switcher .domain:last-child { border-right: none; }

#switcher .domain:hover {
  color: var(--warm);
  background: rgba(200,169,110,0.06);
}

#switcher .domain.active {
  color: var(--accent);
  background: rgba(200,169,110,0.1);
}

/* ── Main content ─────────────────────────────────────────── */
main#content {
  position: relative;
  z-index: 5;
  max-width: 52rem;
  margin: 0 auto;
  padding: 8rem 2rem 4rem;
}

/* ── Header ───────────────────────────────────────────────── */
header {
  margin-bottom: 4rem;
}

.kicker {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 0.75rem;
  transition: opacity 0.4s;
}

h1 {
  font-size: clamp(2.4rem, 5vw, 4rem);
  font-weight: 400;
  color: var(--warm);
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin-bottom: 1.25rem;
  transition: opacity 0.4s;
}

.lede {
  font-size: 1.05rem;
  color: var(--text);
  max-width: 38rem;
  opacity: 0.85;
  transition: opacity 0.4s;
}

/* ── Strands ──────────────────────────────────────────────── */
.strands {
  display: flex;
  flex-direction: column;
  gap: 3rem;
}

.strand {
  position: relative;
  padding-left: 1.5rem;
  border-left: 1px solid var(--dim);
  transition: border-color 0.4s;
}

.strand:hover {
  border-color: var(--accent);
}

.strand h2 {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.6rem;
}

.strand p {
  font-size: 0.95rem;
  color: var(--text);
  opacity: 0.8;
  max-width: 34rem;
}

.strand em {
  color: var(--accent);
  font-style: normal;
}

/* ── Margin notes ─────────────────────────────────────────── */
.margin-note {
  position: absolute;
  right: -14rem;
  top: 0;
  width: 12rem;
  font-family: var(--mono);
  font-size: 0.65rem;
  line-height: 1.5;
  color: var(--muted);
  border-left: 1px solid var(--dim);
  padding-left: 0.75rem;
  transition: color 0.3s;
}

.strand:hover .margin-note {
  color: var(--accent);
}

@media (max-width: 900px) {
  .margin-note {
    position: static;
    width: auto;
    border-left: none;
    border-top: 1px solid var(--dim);
    padding: 0.5rem 0 0;
    margin-top: 0.75rem;
  }
}

/* ── Footer ───────────────────────────────────────────────── */
footer {
  margin-top: 5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--dim);
  font-family: var(--mono);
  font-size: 0.65rem;
  color: var(--muted);
  letter-spacing: 0.04em;
}

/* ── Content fade transition ──────────────────────────────── */
#content.fading {
  opacity: 0;
  transform: translateY(4px);
  transition: opacity 0.25s ease, transform 0.25s ease;
}

#content.visible {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.35s ease 0.1s, transform 0.35s ease 0.1s;
}