/* ===========================================================
   The Learning Oven — stylesheet
   Paper/ink palette pulled from the source diagrams themselves.
   =========================================================== */

@import url('https://fonts.googleapis.com/css2?family=Fraunces:opsz,wght@9..144,400;9..144,500;9..144,600&family=Archivo:wght@400;500;600;700&display=swap');

:root{
  --paper: #EAE6DC;
  --paper-raised: #F2EFE7;
  --paper-dim: #DCD7C9;
  --ink: #26221E;
  --ink-soft: #4B453E;
  --ink-faint: #837B6E;
  --brick: #8A3B2A;
  --brick-dim: #C98F7E;
  --forest: #2E5A44;
  --forest-dim: #9CBBAB;
  --line: rgba(38,34,30,0.14);
  --serif: "Fraunces", ui-serif, Georgia, "Iowan Old Style", serif;
  --sans: "Archivo", ui-sans-serif, "Segoe UI", system-ui, sans-serif;
  --measure: 65ch;
  --radius: 8px;
}

*{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }

body{
  margin:0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 19px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

@media (prefers-reduced-motion: reduce){
  html{ scroll-behavior:auto; }
  *{ animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}

::selection{ background: var(--brick-dim); color: var(--ink); }

a{ color: inherit; }
h1,h2,h3{ font-family: var(--serif); font-weight: 600; line-height:1.15; margin: 0 0 0.4em; }
p{ margin: 0 0 1.3em; max-width: var(--measure); }
strong{ font-weight: 600; }
em{ font-style: italic; }

/* ---------- Top chrome ---------- */
.site-header{
  position: sticky;
  top: 0;
  z-index: 40;
  display:flex;
  align-items:center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1.5rem;
  background: rgba(234,230,220,0.92);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--line);
  font-family: var(--sans);
}

.brand{
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.05rem;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.depth-switch{
  display:flex;
  gap: 0.25rem;
  background: var(--paper-dim);
  border-radius: 999px;
  padding: 3px;
}
.depth-switch button{
  font-family: var(--sans);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.4rem 0.9rem;
  border: none;
  border-radius: 999px;
  background: transparent;
  color: var(--ink-soft);
  cursor: pointer;
  transition: background 0.25s ease, color 0.25s ease;
}
.depth-switch button.active{
  background: var(--ink);
  color: var(--paper);
}
.depth-switch button:focus-visible, button:focus-visible, a:focus-visible{
  outline: 2px solid var(--brick);
  outline-offset: 2px;
}

/* ---------- Layout shell ---------- */
.shell{
  display:grid;
  grid-template-columns: 1fr;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

@media (min-width: 980px){
  .shell.has-rail{
    grid-template-columns: 220px minmax(0,1fr);
    gap: 3rem;
  }
}

/* ---------- Hero ---------- */
.hero{
  max-width: 900px;
  margin: 4.5rem auto 2.5rem;
  padding: 0 1.5rem;
  text-align: left;
}
.hero .kicker{
  font-family: var(--sans);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--brick);
  margin-bottom: 0.9rem;
}
.hero h1{
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  max-width: 14ch;
}
.hero p.deck{
  font-size: 1.2rem;
  color: var(--ink-soft);
  max-width: 46ch;
}
.hero .begin-btn{
  display:inline-block;
  margin-top: 1.2rem;
  font-family: var(--sans);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.75rem 1.4rem;
  background: var(--ink);
  color: var(--paper);
  border-radius: var(--radius);
  text-decoration: none;
  transition: transform 0.2s ease;
}
.hero .begin-btn:hover{ transform: translateY(-1px); }

/* ---------- Chapter rail ---------- */
.chapter-rail{
  position: sticky;
  top: 5.2rem;
  align-self: start;
  max-height: calc(100vh - 7rem);
  overflow-y: auto;
  font-family: var(--sans);
  padding-bottom: 2rem;
}
.chapter-rail ul{ list-style:none; margin:0; padding:0; }
.chapter-rail li{ margin-bottom: 0.15rem; }
.chapter-rail a{
  display:block;
  text-decoration:none;
  padding: 0.45rem 0.5rem;
  border-radius: 6px;
  color: var(--ink-faint);
  font-size: 0.86rem;
  transition: color 0.2s ease, background 0.2s ease;
}
.chapter-rail a:hover{ background: var(--paper-raised); color: var(--ink); }
.chapter-rail a.current{ color: var(--ink); background: var(--paper-raised); font-weight: 600; }
.chapter-rail .rail-num{
  display:block;
  font-variant-numeric: oldstyle-nums;
  color: var(--brick);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.15rem;
}
.chapter-rail .rail-title{
  display:block;
  line-height: 1.3;
}
.chapter-rail-toggle{ display:none; }

/* ---------- Reading column ---------- */
.reading{ min-width: 0; padding-bottom: 8rem; }

.tier-title{ margin: 1rem 0 2rem; }
.tier-title h1{ font-size: 2.1rem; }
.tier-subtitle{ font-family: var(--sans); color: var(--ink-faint); font-size: 0.95rem; margin:0; }

p.lede{ font-size: 1.15rem; color: var(--ink-soft); }

.chapter{ padding-top: 2.4rem; margin-top: 1rem; border-top: 1px solid var(--line); scroll-margin-top: 5rem; }
.chapter:first-of-type{ border-top: none; }
.chapter-head{ margin-bottom: 1.2rem; }
.chapter-eyebrow{
  display:block;
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--brick);
  margin-bottom: 0.3rem;
}
.chapter h2{ font-size: 1.6rem; max-width: 24ch; }

.ann-section{ padding-top: 2rem; margin-top: 1rem; border-top: 1px solid var(--line); scroll-margin-top: 5rem; }
.ann-section:first-of-type{ border-top:none; }

/* The account's own final line, wherever it falls \u2014 no text is added, only emphasis. */
.tier-full .chapter:last-of-type p:last-of-type,
.tier-annotated .ann-section:last-of-type p:last-of-type{
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--line);
  font-style: italic;
  color: var(--ink-soft);
  font-size: 1.15rem;
}

/* ---------- Status tags ---------- */
.status-line{ margin: -0.6em 0 1.4em; }
.status-tag{
  display:inline-block;
  font-family: var(--sans);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  padding: 0.32rem 0.65rem;
  border-radius: 999px;
  background: var(--paper-dim);
  color: var(--ink-soft);
  border: 1px solid var(--line);
}
.status-tag[data-status="lore"]{ background: rgba(46,90,68,0.12); color: var(--forest); border-color: rgba(46,90,68,0.3); }
.status-tag[data-status="hos"]{ background: rgba(138,59,42,0.1); color: var(--brick); border-color: rgba(138,59,42,0.28); }

/* ---------- Diagram widgets ---------- */
.diagram-widget{
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1.4rem 1.4rem 1.6rem;
  margin: 1.6rem 0 2.2rem;
  max-width: none;
}
.diagram-caption{
  font-family: var(--sans);
  font-size: 0.85rem;
  color: var(--ink-faint);
  margin-bottom: 0.6rem;
}
.diagram-stage{ width:100%; }
.diagram-stage svg{ width:100%; height:auto; display:block; }
.diagram-stage.small svg{ max-width: 640px; margin: 0 auto; display:block; }

.d-circle{ fill: var(--paper); stroke: var(--ink); stroke-width: 1.4; }
.d-box.product{ fill: var(--paper); stroke: var(--ink); stroke-width: 1.4; }
.d-arrow{ stroke: var(--ink-faint); stroke-width: 1.4; marker-end: none; }
.d-arrow.out{ stroke: var(--brick); }
.d-label{ font-family: var(--sans); fill: var(--ink); font-size: 15px; }
.d-label.small{ font-size: 13px; }
.d-label.tiny{ font-size: 10.5px; }
.d-label.dim{ fill: var(--ink-faint); }
.d-label.center{ text-anchor: middle; }
.d-label.mid{ text-anchor: middle; }
.d-label.small-strong{ font-size: 13px; font-weight: 600; text-anchor: middle; }

#layer-a, #layer-a-2, #layer-a-ann{ transition: opacity 0.5s ease; }
#layer-b, #layer-b-2, #layer-b-ann{ transition: opacity 0.6s ease 0.35s; }
#a-outbound, #a-outbound-2, #a-outbound-ann{ transition: opacity 0.5s ease, transform 0.5s ease; transform-origin: 680px 250px; }
#a-outbound.fading, #a-outbound-2.fading, #a-outbound-ann.fading{ opacity: 0; transform: scale(0.85); }
#a-core, #a-core-2, #a-core-ann{ transition: opacity 0.5s ease 0.15s; }

.pie-slice.tf{ fill: var(--brick); opacity: 0.88; }
.pie-slice.lc{ fill: var(--ink); opacity: 0.85; }
.pie-slice.smc{ fill: var(--forest); opacity: 0.88; }
.d-circle.center-hub{ fill: var(--paper); }
.pie-label{ fill: var(--paper); }
text.pie-label.dim{ fill: rgba(234,230,220,0.75); }

.diagram-controls{ margin-top: 1rem; }
.diagram-btn{
  font-family: var(--sans);
  font-weight: 600;
  font-size: 0.88rem;
  padding: 0.6rem 1.1rem;
  border-radius: 999px;
  border: 1px solid var(--ink);
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}
.diagram-btn:hover{ background: var(--ink); color: var(--paper); }
.diagram-btn.small{ margin-top: 0.9rem; }
.diagram-note{
  font-family: var(--sans);
  font-size: 0.9rem;
  color: var(--ink-soft);
  margin: 0.7rem 0 0;
  max-width: 56ch;
}

/* step diagram (community progression) */
.step-bar{ fill: var(--paper-dim); stroke: var(--line); }
.step-bar.one{ fill: var(--brick); opacity: 0.18; }
.step-bar.two{ fill: var(--ink); opacity: 0.14; }
.step-bar.three{ fill: var(--forest); opacity: 0.2; }
.step-num{ font-family: var(--sans); font-weight: 700; font-size: 13px; }
.step-title{ font-family: var(--serif); font-weight: 600; font-size: 17px; }
.step-copy{ font-size: 13.5px; }
.step{ opacity: 0.25; transition: opacity 0.5s ease; }
.step.revealed{ opacity: 1; }

/* ---------- Timeline ---------- */
.timeline-wrap{
  margin: 0 auto 3rem;
  max-width: 1180px;
  padding: 0 1.5rem;
}
.timeline{
  display:flex;
  gap: 0;
  border-top: 2px solid var(--ink);
  position: relative;
  padding-top: 1.6rem;
  overflow-x: auto;
}
.timeline-item{
  flex: 1 1 0;
  min-width: 160px;
  position: relative;
  padding-right: 1.2rem;
}
.timeline-item::before{
  content:"";
  position:absolute;
  top:-1.6rem;
  left:-4px;
  width:8px; height:8px;
  border-radius:50%;
  background: var(--ink);
}
.timeline::after{
  content:"";
  position:absolute;
  top:0;
  right:0;
  height:2px;
  width:70px;
  background: linear-gradient(to right, transparent, var(--paper));
  pointer-events:none;
}
.timeline-item .t-year{ font-family: var(--sans); font-size: 0.75rem; color: var(--brick); font-weight:700; }
.timeline-item h3{ font-family: var(--sans); font-size: 0.98rem; margin: 0.25rem 0 0.35rem; }
.timeline-item p{ font-family: var(--sans); font-size: 0.82rem; color: var(--ink-soft); max-width: 26ch; margin:0; }

/* ---------- Footer ---------- */
.site-footer{
  font-family: var(--sans);
  font-size: 0.82rem;
  color: var(--ink-faint);
  text-align:center;
  padding: 3rem 1.5rem 4rem;
}

/* ---------- Utility ---------- */
[hidden]{ display:none !important; }

@media (max-width: 640px){
  body{ font-size: 17px; }
  .hero{ margin-top: 2.5rem; }
  .site-header{ padding: 0.7rem 1rem; }
  .brand{ font-size: 0.92rem; }
}