/* ========================================================================
   /skript — Lecture-Reader · Variante C „Buch mit Kapiteln“
   Light-Editorial, exakt im Design-System von chaos-explorer (styles.css).
   Fraunces (display) · Instrument Sans (body) · JetBrains Mono (Zahlen/Labels)
   KaTeX-CSS wird in index.html geladen (Formeln sind vorgerendert).
   ======================================================================== */

:root {
  --bg:       #f6f3ea;
  --paper:    #fdfbf4;
  --paper-2:  #f1ecdf;
  --line:     #e1dbcb;
  --line-2:   #c6bfac;

  --ink:      #141310;
  --ink-2:    #3a3630;
  --ink-dim:  #625b4f;
  --ink-mute: #8e867a;

  --accent:      #8d2d1c;
  --accent-soft: #c55b3b;
  --cool:        #203955;
  --cool-soft:   #6e8aad;
  --warm:        #6e4a2c;
  --ok:          #355b2d;

  --radius:    6px;
  --radius-sm: 3px;

  --font-display: "Fraunces", "Times New Roman", serif;
  --font-body:    "Instrument Sans", system-ui, sans-serif;
  --font-mono:    "JetBrains Mono", ui-monospace, monospace;

  /* Höhe von Kopf(control-bar) für sticky-Offsets / scroll-margin. */
  --control-h: 54px;
  --page-pad:  56px;
  --shell-max: 1680px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

/* `hidden`-Attribut gewinnt immer. */
[hidden] { display: none !important; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

::selection { background: var(--accent); color: var(--paper); }

.grain {
  position: fixed; inset: 0;
  pointer-events: none;
  opacity: 0.04;
  mix-blend-mode: multiply;
  z-index: 1;
  width: 100%; height: 100%;
}

a { color: var(--accent); text-decoration: none; border-bottom: 1px solid var(--line-2); }
a:hover { border-bottom-color: var(--accent); }

kbd {
  font-family: var(--font-mono);
  font-size: 10.5px;
  padding: 1px 5px;
  border: 1px solid var(--line-2);
  border-bottom-width: 2px;
  border-radius: 3px;
  background: var(--paper);
  color: var(--ink-dim);
}

.katex { font-size: 1em; }
.katex-display { margin: 8px 0; overflow-x: auto; overflow-y: hidden; }

/* ------------------------------------------------------------------ Kopf */

.site-header {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: end;
  gap: 40px;
  padding: 36px var(--page-pad) 20px;
  border-bottom: 1px solid var(--line);
  max-width: var(--shell-max);
  margin: 0 auto;
}

.brand-kicker {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--ink-mute);
  display: block;
  margin-bottom: 8px;
}
.brand-title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(28px, 3.5vw, 44px);
  line-height: 0.98;
  letter-spacing: -0.022em;
  margin: 0;
  color: var(--ink);
  font-variation-settings: "SOFT" 0, "opsz" 144;
}
.brand-title em {
  font-style: italic;
  font-weight: 300;
  color: var(--ink-2);
  font-variation-settings: "SOFT" 20, "opsz" 144;
}
.brand-meta {
  margin: 12px 0 0;
  font-size: 13px;
  color: var(--ink-dim);
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: baseline;
}
.brand-meta .meta-course   { color: var(--ink-2); font-weight: 500; }
.brand-meta .meta-sep      { color: var(--ink-mute); }
.brand-meta .meta-lecturer,
.brand-meta .meta-term     { color: var(--ink-dim); }

.site-nav {
  display: flex;
  gap: 8px;
  justify-self: end;
}
.nav-link {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 6px 13px;
  border: 1px solid var(--line-2);
  border-radius: 3px;
  color: var(--ink-dim);
  background: var(--paper);
  transition: color 120ms, border-color 120ms;
  white-space: nowrap;
}
.nav-link:hover { color: var(--accent); border-color: var(--accent); }
.nav-back { color: var(--ink-2); }
/* Klausur als CTA — spiegelt die Hauptseite (nav-link--cta mit Accent). */
.nav-link--cta { color: var(--paper); background: var(--accent); border-color: var(--accent); }
.nav-link--cta:hover { color: var(--paper); background: #7a2617; border-color: #7a2617; }

/* --------------------------------------------------- Steuerungsleiste */

.control-bar {
  position: sticky;
  top: 0;
  z-index: 30;
  display: flex;
  align-items: center;
  gap: 22px;
  padding: 9px var(--page-pad);
  min-height: var(--control-h);
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
/* Die Leiste läuft randlos über die Seite; Inhalt bleibt am Shell ausgerichtet. */
.control-bar { max-width: none; }

.progress {
  display: flex;
  align-items: baseline;
  gap: 8px;
  min-width: 0;
  flex-shrink: 1;
}
.progress-num {
  font-family: var(--font-mono);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  color: var(--ink);
  white-space: nowrap;
}
.progress-sep { color: var(--ink-mute); }
.progress-chapter {
  font-family: var(--font-display);
  font-style: italic;
  font-size: 15px;
  font-variation-settings: "SOFT" 30, "opsz" 20;
  color: var(--accent);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.control-tools {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 18px;
}

/* Suche */
.search { position: relative; display: flex; align-items: center; }
.search-label {
  position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0);
}
.search-input {
  font-family: var(--font-body);
  font-size: 13px;
  color: var(--ink);
  width: 260px;
  max-width: 34vw;
  padding: 6px 12px;
  border: 1px solid var(--line-2);
  border-radius: 4px;
  background: var(--paper);
  outline: none;
  transition: border-color 120ms, box-shadow 120ms;
}
.search-input::placeholder { color: var(--ink-mute); }
.search-input:focus {
  border-color: var(--accent);
  box-shadow: inset 0 0 0 1px var(--accent);
}
.search-count {
  position: absolute;
  right: 10px; top: 50%; transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--ink-mute);
  pointer-events: none;
}

/* Erklärtext-Toggle (Schalter im Stil von LectureDeck) */
.explain-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  user-select: none;
}
.explain-toggle input { position: absolute; opacity: 0; width: 0; height: 0; }
.explain-toggle-track {
  width: 34px; height: 18px;
  border-radius: 10px;
  background: var(--line-2);
  border: 1px solid var(--line-2);
  position: relative;
  transition: background 140ms;
  flex-shrink: 0;
}
.explain-toggle-knob {
  position: absolute;
  top: 1px; left: 1px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--paper);
  box-shadow: 0 1px 2px rgba(0,0,0,0.2);
  transition: transform 140ms;
}
.explain-toggle input:checked + .explain-toggle-track { background: var(--accent); border-color: var(--accent); }
.explain-toggle input:checked + .explain-toggle-track .explain-toggle-knob { transform: translateX(16px); }
.explain-toggle input:focus-visible + .explain-toggle-track { box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 30%, transparent); }
.explain-toggle-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ink-dim);
  white-space: nowrap;
}

/* Drawer-Toggle (nur Mobile sichtbar) */
.drawer-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-dim);
  background: var(--paper);
  border: 1px solid var(--line-2);
  border-radius: 4px;
  padding: 6px 11px;
  cursor: pointer;
}
.drawer-toggle-bars { display: inline-flex; flex-direction: column; gap: 3px; }
.drawer-toggle-bars span { width: 14px; height: 1.5px; background: var(--ink-dim); border-radius: 1px; }

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

.reader-layout {
  position: relative;
  z-index: 2;
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 0 var(--page-pad) 100px;
  display: grid;
  grid-template-columns: 288px minmax(0, 1fr);
  gap: 48px;
  align-items: start;
}

/* ---------------------------------------------------------- Sidebar */

.sidebar {
  position: sticky;
  top: var(--control-h);
  align-self: start;
  height: calc(100vh - var(--control-h));
}
.sidebar-inner {
  height: 100%;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: 26px 18px 40px 0;
  scrollbar-width: thin;
  scrollbar-color: var(--line-2) transparent;
}
.sidebar-inner::-webkit-scrollbar { width: 8px; }
.sidebar-inner::-webkit-scrollbar-thumb { background: var(--line-2); border-radius: 4px; }

.sidebar-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}
.sidebar-title {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-mute);
}
.drawer-close {
  display: none;
  font-size: 24px;
  line-height: 1;
  background: none;
  border: none;
  color: var(--ink-dim);
  cursor: pointer;
  padding: 0 4px;
}

.toc { display: flex; flex-direction: column; }

/* Kapitel-Gruppe (Level-1 + eingerückte Level-2) */
.toc-group { margin-bottom: 2px; }
.toc-group.is-hidden { display: none; }

.toc-link {
  display: block;
  color: var(--ink-dim);
  border: none;
  border-left: 2px solid transparent;
  padding: 5px 10px 5px 12px;
  border-radius: 0 3px 3px 0;
  transition: background 120ms, color 120ms, border-color 120ms;
  line-height: 1.35;
}
.toc-link:hover { background: var(--paper-2); color: var(--ink); }

/* Level-1 fett (Kapitel) */
.toc-l1 {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--ink-2);
  font-variation-settings: "SOFT" 10, "opsz" 30;
  margin-top: 10px;
}
.toc-l1 .toc-range {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 400;
  color: var(--ink-mute);
  margin-left: 6px;
  font-variant-numeric: tabular-nums;
}
/* Level-2 eingerückt (Abschnitte) */
.toc-l2 {
  font-family: var(--font-body);
  font-size: 12.5px;
  color: var(--ink-dim);
  padding-left: 24px;
}
.toc-l2.is-hidden { display: none; }

/* aktiver Eintrag (Scroll-Spy) */
.toc-link.active {
  color: var(--accent);
  border-left-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 7%, transparent);
}
.toc-l1.active { color: var(--accent); }

/* Such-Highlight in der Sidebar */
.toc-link mark {
  background: color-mix(in srgb, var(--accent-soft) 32%, transparent);
  color: inherit;
  border-radius: 2px;
  padding: 0 1px;
}

.toc-empty {
  font-size: 12.5px;
  color: var(--ink-mute);
  font-style: italic;
  padding: 8px 12px;
}

/* ---------------------------------------------------- Hauptspalte */

.reader-main { min-width: 0; padding-top: 26px; }
.reader-main:focus { outline: none; }

.reader-loading {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--ink-mute);
  padding: 60px 0;
  text-align: center;
}

/* ----------------------------- Kapitel-Trenner (Buch-Dramaturgie) */

.chapter-divider {
  scroll-margin-top: calc(var(--control-h) + 14px);
  padding: 60px 0 30px;
  margin-top: 26px;
  border-top: 1px solid var(--line);
}
.chapter-divider:first-child { border-top: none; margin-top: 0; padding-top: 12px; }

.chapter-eyebrow {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 12px;
}
.chapter-kicker {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--accent);
}
.chapter-range {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--ink-mute);
  font-variant-numeric: tabular-nums;
}
.chapter-heading {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(30px, 4.2vw, 52px);
  line-height: 1.02;
  letter-spacing: -0.025em;
  color: var(--ink);
  margin: 0;
  font-variation-settings: "SOFT" 0, "opsz" 144;
  max-width: 20ch;
}
.chapter-heading .num {
  font-style: italic;
  font-weight: 300;
  color: var(--accent-soft);
  font-variation-settings: "SOFT" 30, "opsz" 144;
  margin-right: 0.3em;
}
/* Ein-Seiten-Kapitel = Abschnitts-Trenner: dezenter. */
.chapter-divider.is-marker { padding: 40px 0 20px; }
.chapter-divider.is-marker .chapter-heading { font-size: clamp(22px, 2.6vw, 30px); color: var(--ink-2); }

/* --------------------------------------------------- Folien-Karten */

.slide-card {
  scroll-margin-top: calc(var(--control-h) + 14px);
  margin: 22px 0;
  /* Perf: offscreen-Karten nicht rendern; Platzhalterhöhe geschätzt
     (4:3-Bild + Label + Erklärtext). auto-Keyword korrigiert nach 1. Render. */
  content-visibility: auto;
  contain-intrinsic-size: auto 1020px;
}

.slide-label {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 6px 10px;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.06em;
}
.slide-label .sl-n {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  text-transform: uppercase;
  letter-spacing: 0.12em;
}
.slide-label .sl-sep { color: var(--line-2); }
.slide-label .sl-chapter { color: var(--ink-mute); text-transform: uppercase; letter-spacing: 0.1em; }
.slide-label .sl-section {
  font-family: var(--font-display);
  font-style: italic;
  font-size: 13.5px;
  letter-spacing: 0;
  color: var(--ink-2);
  font-variation-settings: "SOFT" 30, "opsz" 14;
}

/* Folienbild — 4:3 1400×1050 auf Papier, dezenter Rahmen & Schatten */
.slide-figure {
  margin: 0;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
  box-shadow: 0 8px 22px -14px rgba(20,19,16,0.35);
}
.slide-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 3;
  border-radius: var(--radius-sm);
  background: #fff;   /* Beamer-Folien sind weiß; verhindert Flackern beim Lazy-Load */
}

/* Erklärtext unter der Folie */
.slide-text {
  margin: 14px 0 0;
  padding: 2px 2px 0;
  max-width: 74ch;
  color: var(--ink-2);
  font-size: 15px;
  line-height: 1.62;
}
.slide-text p { margin: 0 0 0.7em; }
.slide-text p:last-child { margin-bottom: 0; }
.slide-text strong { color: var(--ink); font-weight: 600; }
.slide-text em { font-style: italic; }
.slide-text ul { margin: 0.3em 0 0.8em; padding-left: 1.3em; }
.slide-text li { margin: 0.2em 0; }
.slide-text .katex { color: var(--ink); }
.slide-text a { border-bottom: 1px solid var(--line-2); }
.slide-text a:hover { border-bottom-color: var(--accent); }

.slide-text-placeholder {
  height: 3.2em; /* reserviert Platz bis zum Lazy-Inject, vermeidet Layout-Sprung */
}

/* Erklärtexte global aus (Toggle) */
body[data-explain="off"] .slide-text,
body[data-explain="off"] .slide-text-placeholder { display: none; }
body[data-explain="off"] .slide-card { contain-intrinsic-size: auto 700px; }

/* Sprung-Highlight nach Suche/Deep-Link */
.slide-card.flash .slide-figure {
  animation: flash 1200ms ease-out;
}
@keyframes flash {
  0%   { box-shadow: 0 0 0 3px var(--accent), 0 8px 22px -14px rgba(20,19,16,0.35); }
  100% { box-shadow: 0 0 0 0 transparent, 0 8px 22px -14px rgba(20,19,16,0.35); }
}

/* ----------------------------------------------- Zurück-nach-oben */

.to-top {
  position: fixed;
  right: 22px; bottom: 22px;
  z-index: 25;
  width: 42px; height: 42px;
  border-radius: 50%;
  border: 1px solid var(--line-2);
  background: var(--paper);
  color: var(--ink-dim);
  font-size: 18px;
  cursor: pointer;
  box-shadow: 0 6px 16px -8px rgba(0,0,0,0.3);
  opacity: 0;
  transform: translateY(8px);
  pointer-events: none;
  transition: opacity 180ms, transform 180ms, color 120ms, border-color 120ms;
}
.to-top.visible { opacity: 1; transform: translateY(0); pointer-events: auto; }
.to-top:hover { color: var(--accent); border-color: var(--accent); }

/* ============================================================ Responsive */

@media (max-width: 1200px) {
  :root { --page-pad: 32px; }
  .reader-layout { grid-template-columns: 248px minmax(0, 1fr); gap: 32px; }
}

@media (max-width: 900px) {
  :root { --page-pad: 20px; }

  .site-header {
    grid-template-columns: 1fr;
    align-items: start;
    gap: 16px;
    padding: 22px var(--page-pad) 16px;
  }
  .site-nav { justify-self: start; }

  .control-bar { gap: 12px; padding: 8px var(--page-pad); }
  .drawer-toggle { display: inline-flex; }
  .progress { display: none; }              /* Platz sparen auf Mobile */
  .control-tools { gap: 10px; }
  .search-input { width: 150px; max-width: 40vw; }
  .explain-toggle-label { display: none; }  /* nur Schalter zeigen */

  .reader-layout {
    grid-template-columns: 1fr;
    gap: 0;
    padding: 0 var(--page-pad) 80px;
  }

  /* Sidebar wird zum Off-Canvas-Drawer */
  .sidebar {
    position: fixed;
    top: 0; left: 0; bottom: 0;
    width: min(320px, 86vw);
    height: 100%;
    z-index: 60;
    background: var(--bg);
    border-right: 1px solid var(--line);
    box-shadow: 12px 0 40px -20px rgba(0,0,0,0.4);
    transform: translateX(-102%);
    transition: transform 240ms cubic-bezier(0.2,0.7,0.25,1);
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-inner { padding: 20px 18px 40px; }
  .drawer-close { display: block; }

  .drawer-backdrop {
    position: fixed; inset: 0;
    z-index: 55;
    background: rgba(20,19,16,0.34);
    -webkit-backdrop-filter: blur(1px);
    backdrop-filter: blur(1px);
  }

  .reader-main { padding-top: 12px; }
  .slide-text { max-width: none; }
}

/* prefers-reduced-motion respektieren */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; }
}