/* ============================================================
   EpiChat — warm academic + terminal-inspired
   ============================================================ */

:root {
  /* base palette — warm academic */
  --paper: oklch(0.97 0.012 80);
  --paper-2: oklch(0.94 0.015 78);
  --paper-3: oklch(0.91 0.018 75);
  --rule: oklch(0.78 0.02 70);
  --ink: oklch(0.22 0.02 40);
  --ink-2: oklch(0.38 0.02 45);
  --ink-3: oklch(0.55 0.02 50);

  /* accent — burgundy (tweakable) */
  --accent-h: 25;
  --accent: oklch(0.42 0.12 var(--accent-h));
  --accent-soft: oklch(0.42 0.12 var(--accent-h) / 0.12);
  --accent-ink: oklch(0.32 0.12 var(--accent-h));

  /* fonts */
  --serif: "Newsreader", "Source Serif Pro", Georgia, serif;
  --mono: "JetBrains Mono", "SF Mono", ui-monospace, Menlo, monospace;

  /* spacing scale */
  --pad: 2rem;
  --measure: 68ch;
  --max: 1200px;

  /* density */
  --density: 1;
}

[data-theme="dark"] {
  --paper: oklch(0.18 0.015 50);
  --paper-2: oklch(0.22 0.018 50);
  --paper-3: oklch(0.26 0.02 50);
  --rule: oklch(0.38 0.02 55);
  --ink: oklch(0.93 0.012 80);
  --ink-2: oklch(0.78 0.015 75);
  --ink-3: oklch(0.60 0.018 65);
  --accent: oklch(0.72 0.13 var(--accent-h));
  --accent-soft: oklch(0.72 0.13 var(--accent-h) / 0.15);
  --accent-ink: oklch(0.82 0.12 var(--accent-h));
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.55;
  font-feature-settings: "ss01", "liga", "onum";
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* paper grain — very subtle */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(90deg, transparent 0 119px, oklch(0.5 0.02 40 / 0.03) 119px 120px),
    repeating-linear-gradient(0deg, transparent 0 23px, oklch(0.5 0.02 40 / 0.025) 23px 24px);
  z-index: 1;
  mix-blend-mode: multiply;
}
[data-theme="dark"] body::before { mix-blend-mode: screen; opacity: 0.4; }

a {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
  transition: border-color 120ms, color 120ms;
}
a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.mono, code, pre, kbd, .tag, .label, .num {
  font-family: var(--mono);
  font-feature-settings: "zero", "ss01";
}

.label {
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-3);
  font-weight: 500;
}

.tag {
  display: inline-block;
  padding: 2px 8px;
  font-size: 0.64rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  border: 1px solid var(--rule);
  color: var(--ink-2);
  border-radius: 2px;
}
.tag.accent {
  color: var(--accent);
  border-color: var(--accent);
}
.tag.filled {
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
}

/* ------------------------------------------------------------
   Layout
   ------------------------------------------------------------ */

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 var(--pad);
  position: relative;
  z-index: 2;
}

.rule {
  border: 0;
  border-top: 1px solid var(--rule);
  margin: 0;
}

.rule-double {
  border: 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  height: 4px;
  margin: 0;
}

section {
  padding: calc(6rem * var(--density)) 0;
  border-top: 1px solid var(--rule);
  position: relative;
}

.section-head {
  display: grid;
  grid-template-columns: 1fr 2.4fr;
  gap: 3rem;
  margin-bottom: 3rem;
  align-items: baseline;
}

.section-index {
  font-family: var(--mono);
  font-size: 1rem;
  letter-spacing: 0.12em;
  color: var(--ink-3);
  text-transform: uppercase;
}
.section-index::before { content: "● "; color: var(--accent); }

.section-title {
  font-family: var(--serif);
  font-weight: 400;
  font-style: italic;
  font-size: clamp(1.8rem, 3.2vw, 2.6rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
  margin: 0;
}
.section-title em {
  font-style: normal;
  color: var(--accent);
}

/* ------------------------------------------------------------
   Nav
   ------------------------------------------------------------ */

.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in oklch, var(--paper) 92%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--rule);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem var(--pad);
  max-width: var(--max);
  margin: 0 auto;
  gap: 2rem;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  border: 0;
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.brand:hover { color: var(--accent); border: 0; }
.brand-mark {
  display: inline-block;
  width: 10px; height: 10px;
  background: var(--accent);
  border-radius: 50%;
  transform: translateY(-1px);
}
.brand-meta {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.nav-links {
  display: flex;
  gap: 1.8rem;
  align-items: center;
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
}
.nav-links a {
  border: 0;
  color: var(--ink-2);
  padding: 0.3rem 0;
  position: relative;
}
.nav-links a:hover { color: var(--accent); }
.nav-links a.active { color: var(--ink); }
.nav-links a.active::before {
  content: "▸ ";
  color: var(--accent);
}

.nav-cta {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 0.55rem 0.9rem;
  background: var(--ink);
  color: var(--paper);
  border: 1px solid var(--ink);
  border-radius: 2px;
  transition: background 140ms, color 140ms;
}
.nav-cta:hover {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--paper);
}

/* ------------------------------------------------------------
   Buttons
   ------------------------------------------------------------ */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.85rem 1.2rem;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--paper);
  border-radius: 2px;
  cursor: pointer;
  transition: all 140ms;
}
.btn:hover { background: var(--accent); border-color: var(--accent); color: var(--paper); }
.btn.ghost { background: transparent; color: var(--ink); }
.btn.ghost:hover { background: var(--ink); color: var(--paper); }
.btn.accent { background: var(--accent); border-color: var(--accent); }

.btn .arrow { transition: transform 140ms; }
.btn:hover .arrow { transform: translateX(3px); }

/* ------------------------------------------------------------
   Display type
   ------------------------------------------------------------ */

.hero-kicker {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 2.2rem;
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}
.hero-kicker span { position: relative; }
.hero-kicker span + span::before {
  content: "·";
  position: absolute;
  left: -0.9rem;
  color: var(--rule);
}
.hero-kicker .status-dot {
  display: inline-block;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
  margin-right: 0.4rem;
  transform: translateY(-1px);
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

.display {
  font-family: var(--serif);
  font-size: clamp(3rem, 7vw, 6.4rem);
  line-height: 0.98;
  letter-spacing: -0.025em;
  font-weight: 400;
  margin: 0 0 2rem;
}
.display em {
  font-style: italic;
  color: var(--accent);
}

.lede {
  font-family: var(--serif);
  font-size: clamp(1.2rem, 1.7vw, 1.45rem);
  line-height: 1.45;
  color: var(--ink-2);
  max-width: 56ch;
  font-weight: 400;
  text-wrap: pretty;
}

/* ------------------------------------------------------------
   Panels, cards, terminal
   ------------------------------------------------------------ */

.panel {
  border: 1px solid var(--rule);
  background: var(--paper-2);
  padding: 1.6rem;
  border-radius: 3px;
}

.terminal {
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.6;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  border-radius: 3px;
  overflow: hidden;
}
.terminal-chrome {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.55rem 0.8rem;
  border-bottom: 1px solid var(--rule);
  background: var(--paper-3);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
}
.terminal-chrome .dots { display: flex; gap: 5px; }
.terminal-chrome .dots i {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--rule);
  display: inline-block;
}
.terminal-chrome .dots i:first-child { background: var(--accent); opacity: 0.75; }
.terminal-chrome .title { margin-left: auto; }
.terminal-body { padding: 1.1rem 1.2rem; }

.prompt { color: var(--ink-3); user-select: none; }
.prompt.user::before { content: "▸ "; color: var(--accent); }
.prompt.sys::before { content: "⎿ "; color: var(--ink-3); }

.kv {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 0.2rem 1.2rem;
  font-family: var(--mono);
  font-size: 0.78rem;
}
.kv dt { color: var(--ink-3); }
.kv dd { margin: 0; color: var(--ink); }

/* leader-dot rows, like a classic reference book */
.leader {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  font-family: var(--mono);
  font-size: 0.82rem;
  padding: 0.45rem 0;
  border-bottom: 1px dotted var(--rule);
}
.leader .name { color: var(--ink); }
.leader .dots {
  flex: 1;
  border-bottom: 1px dotted var(--rule);
  margin: 0 0.3rem;
  transform: translateY(-4px);
}
.leader .val { color: var(--ink-2); }

/* ------------------------------------------------------------
   Grid helpers
   ------------------------------------------------------------ */

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 2.2rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }

@media (max-width: 900px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .section-head { grid-template-columns: 1fr; gap: 1rem; }
  :root { --pad: 1.25rem; }
}

/* ------------------------------------------------------------
   Footer
   ------------------------------------------------------------ */

footer.site {
  border-top: 1px solid var(--rule);
  padding: 3rem 0 2rem;
  margin-top: 0;
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--ink-3);
}
footer.site .cols {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 3rem;
}
footer.site h4 {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin: 0 0 0.8rem;
  font-weight: 500;
}
footer.site ul { list-style: none; padding: 0; margin: 0; }
footer.site li { padding: 0.25rem 0; }
footer.site a { border: 0; color: var(--ink-2); }
footer.site a:hover { color: var(--accent); }
footer.site .ascii {
  font-size: 0.72rem;
  color: var(--ink-3);
  white-space: pre;
  line-height: 1.2;
  opacity: 0.7;
}
footer.site .bottom {
  display: flex;
  justify-content: space-between;
  border-top: 1px solid var(--rule);
  padding-top: 1.2rem;
  font-size: 0.72rem;
}

@media (max-width: 900px) {
  footer.site .cols { grid-template-columns: 1fr 1fr; }
}

/* ------------------------------------------------------------
   Tweaks panel
   ------------------------------------------------------------ */

.tweaks {
  position: fixed;
  bottom: 1.25rem;
  right: 1.25rem;
  z-index: 100;
  width: 280px;
  background: var(--paper);
  border: 1px solid var(--ink);
  border-radius: 3px;
  font-family: var(--mono);
  font-size: 0.76rem;
  box-shadow: 0 12px 40px oklch(0 0 0 / 0.12);
  display: none;
}
.tweaks.on { display: block; }
.tweaks h3 {
  margin: 0;
  padding: 0.6rem 0.9rem;
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  border-bottom: 1px solid var(--rule);
  background: var(--ink);
  color: var(--paper);
}
.tweaks .group {
  padding: 0.8rem 0.9rem;
  border-bottom: 1px solid var(--rule);
}
.tweaks .group:last-child { border-bottom: 0; }
.tweaks label {
  display: block;
  font-size: 0.64rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 0.4rem;
}
.tweaks .swatches { display: flex; gap: 0.3rem; }
.tweaks .sw {
  width: 22px; height: 22px;
  border-radius: 50%;
  border: 1px solid var(--rule);
  cursor: pointer;
}
.tweaks .sw.on { outline: 2px solid var(--ink); outline-offset: 2px; }

.tweaks .opts { display: flex; gap: 0.3rem; flex-wrap: wrap; }
.tweaks .opt {
  padding: 0.35rem 0.55rem;
  border: 1px solid var(--rule);
  background: var(--paper-2);
  cursor: pointer;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-2);
  border-radius: 2px;
}
.tweaks .opt.on {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}