/* ===========================================================
   Reader-View — Stoffkatalog-Browser
   Mobile-First. Tabs auf Mobile, 2-Column-Grid ab 768px.
   =========================================================== */

/* ---------- Header-Top mit Filter-Button rechts ---------- */
.reader__header-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.4rem;
}
.reader__header-title {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.2;
}

/* Filter-Button: rundes Icon-Only mit Eye-Icon */
.reader__filter-btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.4rem;
  height: 2.4rem;
  padding: 0;
  background: var(--color-surface-hover);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  font: inherit;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: background 180ms ease, border-color 180ms ease, color 180ms ease, box-shadow 180ms ease, transform 100ms ease;
  flex-shrink: 0;
  box-shadow: var(--shadow-sm);
}
.reader__filter-btn:hover {
  background: var(--color-surface-active);
  color: var(--color-text);
  border-color: var(--color-border-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}
.reader__filter-btn:active { transform: translateY(0); }
.reader__filter-btn:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

/* Active = "Gelesene ausgeblendet" */
.reader__filter-btn.is-active {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-hover) 100%);
  border-color: var(--color-primary);
  color: var(--color-on-accent);
  box-shadow: 0 2px 10px -2px color-mix(in srgb, var(--color-primary) 45%, transparent);
}
.reader__filter-btn.is-active:hover {
  filter: brightness(1.08);
  box-shadow: 0 4px 14px -2px color-mix(in srgb, var(--color-primary) 55%, transparent);
}

/* Eye-Icon: SVG, mit Slash der nur bei is-active sichtbar wird */
.reader__filter-btn-icon {
  flex-shrink: 0;
  transition: transform 200ms ease;
}
.reader__filter-icon-slash {
  stroke-dasharray: 32;
  stroke-dashoffset: 32;
  transition: stroke-dashoffset 250ms ease;
}
.reader__filter-btn.is-active .reader__filter-icon-slash {
  stroke-dashoffset: 0;
}
.reader__filter-btn.is-active .reader__filter-btn-icon {
  transform: scale(1.05);
}


/* Hide-Read Modus: alle als gelesen markierten li-Items ausblenden */
.reader--hide-read .reader__node--li.is-read {
  display: none;
}

/* ---------- Container ---------- */
.reader {
  display: flex;
  flex-direction: column;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  overflow: hidden;
  min-height: calc(100vh - 8rem);
}

/* ---------- Mobile-Tabs (default, ab 768px versteckt) ---------- */
.reader__tabs {
  display: flex;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  flex-shrink: 0;
}
.reader__tab {
  flex: 1;
  padding: 0.85rem 1rem;
  background: transparent;
  border: none;
  border-bottom: 3px solid transparent;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: color 0.18s ease, border-color 0.18s ease, background-color 0.18s ease;
}
.reader__tab:hover {
  color: var(--color-text);
  background: var(--color-surface-hover);
}
.reader__tab.is-active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}
.reader__tab:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: -2px;
}

/* ---------- Hauptbereiche ---------- */
.reader__tree,
.reader__detail {
  width: 100%;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--color-border-hover) transparent;
}

.reader__tree::-webkit-scrollbar,
.reader__detail::-webkit-scrollbar {
  width: 8px;
}
.reader__tree::-webkit-scrollbar-thumb,
.reader__detail::-webkit-scrollbar-thumb {
  background: var(--color-border-hover);
  border-radius: 4px;
}

/* Mobile: nur eines sichtbar (via .is-active) */
.reader__tree,
.reader__detail {
  display: none;
}
.reader__tree.is-active,
.reader__detail.is-active {
  display: block;
}

/* ---------- Tree (Sidebar) ---------- */
.reader__tree {
  background: var(--bg);
  padding: 0.5rem 0;
  max-height: calc(100vh - 12rem);
}

/* Node-Container (pb / tf wrappen ihre Kinder) */
.reader__node {
  position: relative;
}

.reader__node-children {
  margin: 0;
  padding: 0;
  list-style: none;
}
.reader__node-children[hidden] {
  display: none;
}

/* ---------- Node-Toggle (Buttons für pb/tf) ---------- */
.reader__node-toggle,
.reader__node-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
  background: transparent;
  border: none;
  border-left: 3px solid transparent;
  padding: 0.55rem 0.85rem;
  font-family: inherit;
  font-size: 0.94rem;
  line-height: 1.35;
  color: var(--color-text);
  text-align: left;
  cursor: pointer;
  border-radius: 0;
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.reader__node-toggle:hover,
.reader__node-link:hover {
  background: var(--color-surface-hover);
}
.reader__node-toggle:focus-visible,
.reader__node-link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: -2px;
  position: relative;
  z-index: 1;
}

/* Caret (Chevron) */
.reader__node-caret {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1rem;
  height: 1rem;
  font-size: 0.78rem;
  color: var(--color-text-muted);
  transition: transform 0.2s ease, color 0.2s ease;
}
.reader__node.is-open > .reader__node-toggle .reader__node-caret {
  transform: rotate(0deg);
  color: var(--color-text);
}

/* Nr-Prefix */
.reader__node-nr {
  flex-shrink: 0;
  font-variant-numeric: tabular-nums;
  font-size: 0.82rem;
  color: var(--color-text-muted);
  font-weight: 600;
}
.reader__node-name {
  flex: 1;
  min-width: 0;
  text-align: left;
  white-space: normal;
  overflow-wrap: anywhere;
}
.reader__node-meta {
  flex-shrink: 0;
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--color-text-muted);
  padding: 0.1rem 0.45rem;
  background: var(--color-surface-muted);
  border-radius: 999px;
}

/* ---------- Ebene 1: Prüfungsbereich (pb) ---------- */
.reader__node--pb > .reader__node-toggle {
  padding-left: 0.75rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
}
.reader__node--pb + .reader__node--pb {
  margin-top: 0.15rem;
}
.reader__node--pb > .reader__node-toggle .reader__node-nr {
  color: var(--color-primary);
  font-size: 0.9rem;
}

/* ---------- Ebene 2: Themenfeld (tf) ---------- */
.reader__node--tf > .reader__node-toggle {
  padding-left: 2rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
}
.reader__node--tf > .reader__node-toggle:hover {
  color: var(--color-text);
}

/* ---------- Ebene 3: Lerninhalt (li) ---------- */
.reader__node--li {
  list-style: none;
  position: relative;
}
.reader__node--li > .reader__node-link {
  padding-left: 3rem;
  padding-top: 0.45rem;
  padding-bottom: 0.45rem;
  font-size: 0.9rem;
  color: var(--color-text);
  border-radius: 0;
}

/* Indent-Marker (subtile vertikale Linie für li-Tiefe) */
.reader__node--li::before {
  content: "";
  position: absolute;
  left: 2.4rem;
  top: 0.2rem;
  bottom: 0.2rem;
  width: 1px;
  background: var(--color-border);
  pointer-events: none;
}

/* Aktiver Stichpunkt */
.reader__node--li.reader__node--active > .reader__node-link {
  background: var(--color-primary-light);
  border-left-color: var(--color-primary);
  color: var(--color-text);
  font-weight: 600;
}
.reader__node--li.reader__node--active::before {
  background: var(--color-primary);
  width: 2px;
}
.reader__node--li.reader__node--active > .reader__node-link:hover {
  background: var(--color-primary-light);
  filter: brightness(0.97);
}

/* Gelesen */
.reader__node--li.is-read > .reader__node-link .reader__node-name::before {
  content: "\002713\0020";
  color: var(--color-success-text, var(--color-success));
  font-weight: 700;
  margin-right: 0.1rem;
}

/* Gedimmt (nicht prüfungsrelevant) */
.reader__node--li.is-dimmed > .reader__node-link {
  opacity: 0.6;
}
.reader__node--li.is-dimmed > .reader__node-link:hover {
  opacity: 0.85;
}

/* Badges in li-Items */
.reader__node-badge {
  flex-shrink: 0;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0.1rem 0.45rem;
  border-radius: 999px;
  background: var(--color-surface-muted);
  color: var(--color-text-muted);
  margin-left: auto;
}
.reader__node-badge--muted {
  background: var(--bg-muted);
  color: var(--color-text-muted);
  font-size: 0.65rem;
}
.reader__node--active .reader__node-badge {
  background: var(--color-primary);
  color: var(--color-on-accent);
}

/* Placeholder */
.reader__placeholder {
  padding: 2rem 1.25rem;
  color: var(--color-text-muted);
  font-style: italic;
  text-align: center;
}

/* ---------- Detail-Panel ---------- */
.reader__detail {
  padding: 1rem 1.1rem 2rem;
  background: var(--color-surface);
}

/* Breadcrumb (kompakt, oben dranklebend) */
.reader__breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin: 0 0 0.5rem;
  line-height: 1.3;
}
.reader__breadcrumb-sep {
  color: var(--color-text-placeholder, var(--color-text-muted));
  margin: 0 0.1rem;
  opacity: 0.7;
}

/* Titel direkt unter Breadcrumb */
.reader__title {
  font-size: 1.45rem;
  font-weight: 700;
  line-height: 1.25;
  color: var(--color-text);
  margin: 0 0 0.75rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--color-border);
}

/* Lead-Text */
.reader__lead {
  font-size: 1rem;
  color: var(--color-text-muted);
  margin: 0 0 1rem;
  line-height: 1.55;
}

/* ---------- Beschreibungs-Blöcke (subtle mit linker Akzent-Linie) ---------- */
.reader__description {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin: 0 0 1.25rem;
}
.reader__desc-block {
  position: relative;
  background: var(--bg-muted);
  border: none;
  border-left: 3px solid var(--color-border-hover);
  border-radius: 0 8px 8px 0;
  padding: 0.8rem 1rem 0.8rem 1rem;
}
.reader__desc-block h4 {
  margin: 0 0 0.35rem;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  font-weight: 700;
}
.reader__desc-block p {
  margin: 0;
  color: var(--color-text);
  line-height: 1.55;
  font-size: 0.95rem;
}
.reader__desc-block--example {
  background: var(--color-info-bg);
  border-left-color: var(--color-primary);
}
.reader__desc-block--example h4 { color: var(--color-info-text); }
.reader__desc-block--example p { color: var(--color-info-text); }
.reader__desc-block--mnemonic {
  background: var(--color-warning-bg);
  border-left-color: var(--color-warning, var(--color-warning-border));
}
.reader__desc-block--mnemonic h4 { color: var(--color-warning-text); }
.reader__desc-block--mnemonic p { color: var(--color-warning-text); }

/* ---------- Relevanz-Badge ---------- */
.reader__relevanz {
  display: inline-block;
  padding: 0.22rem 0.7rem;
  border-radius: 999px;
  font-size: 0.74rem;
  font-weight: 600;
  text-transform: capitalize;
  background: var(--bg-muted);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  margin-bottom: 0.5rem;
}
.reader__relevanz--hoch {
  background: var(--color-success-bg);
  color: var(--color-success-text);
  border-color: var(--color-success-border);
}
.reader__relevanz--mittel {
  background: var(--color-warning-bg);
  color: var(--color-warning-text);
  border-color: var(--color-warning-border);
}
.reader__relevanz--niedrig,
.reader__relevanz--gering {
  background: var(--bg-muted);
  color: var(--color-text-muted);
  border-color: var(--color-border);
}

/* ---------- Coverage-Box (Aufgaben-Zähler) ---------- */
.reader__coverage {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  padding: 0.85rem 1rem;
  background: var(--color-info-bg);
  border: 1px solid var(--color-info-border);
  border-left: 3px solid var(--color-primary);
  border-radius: 10px;
  margin: 1rem 0 1.25rem;
}
.reader__coverage-summary {
  margin: 0;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-info-text);
}

/* ---------- Actions (Markieren-Button) ---------- */
.reader__actions {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin: 0 0 1.5rem;
}
.reader__mark {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease, transform 0.1s ease;
}
.reader__mark:hover {
  background: var(--color-surface-hover);
  border-color: var(--color-border-hover);
}
.reader__mark:active {
  transform: translateY(1px);
}
.reader__mark.is-read {
  background: var(--color-success-bg);
  border-color: var(--color-success-border);
  color: var(--color-success-text);
}
.reader__mark.is-read:hover {
  filter: brightness(0.97);
}
.reader__mark:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ---------- Verknüpfte Aufgaben (Karten-Grid mit Badge) ---------- */
.reader__aufgaben {
  margin-top: 1.5rem;
}
.reader__aufgaben h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  margin: 0 0 0.75rem;
}
.reader__aufgaben-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 14rem), 1fr));
  gap: 0.5rem;
}
.reader__aufgaben-list > li {
  list-style: none;
}
.reader__aufgabe-link {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.65rem 0.85rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  text-decoration: none;
  color: var(--color-text);
  font-size: 0.9rem;
  transition: border-color 0.15s ease, box-shadow 0.15s ease, transform 0.1s ease, background-color 0.15s ease;
}
.reader__aufgabe-link:hover {
  background: var(--color-surface-hover);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-sm, 0 2px 6px rgba(37, 99, 235, 0.1));
  transform: translateY(-1px);
}
.reader__aufgabe-link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}
.reader__aufgabe-icon {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.4rem;
  height: 1.4rem;
  color: var(--color-primary);
  font-weight: 700;
  transition: transform 0.15s ease;
}
.reader__aufgabe-link:hover .reader__aufgabe-icon {
  transform: translateX(2px);
}
.reader__aufgabe-id {
  flex: 1;
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-primary);
  padding: 0.2rem 0.5rem;
  background: var(--color-primary-light);
  border-radius: 6px;
  letter-spacing: 0.01em;
}

/* Empty-State */
.reader__empty {
  text-align: center;
  padding: 1.5rem 1rem;
  color: var(--color-text-muted);
  font-style: italic;
  background: var(--bg-muted);
  border-radius: 8px;
  margin: 0.5rem 0 0;
}

/* ===========================================================
   Desktop ab 768px: 2-Column-Layout
   =========================================================== */
@media (min-width: 768px) {
  .reader {
    display: grid;
    grid-template-columns: 320px 1fr;
    gap: 0;
    height: calc(100vh - 8rem);
    min-height: 32rem;
    max-width: 1400px;
    margin: 0 auto;
  }

  /* Tabs auf Desktop ausblenden */
  .reader__tabs {
    display: none;
  }

  /* Beide Spalten immer sichtbar */
  .reader__tree,
  .reader__detail {
    display: block;
    max-height: none;
    height: 100%;
  }

  .reader__tree {
    border-right: 1px solid var(--color-border);
    padding: 0.75rem 0;
  }

  .reader__detail {
    padding: 1.5rem 2rem 2.5rem;
  }

  .reader__title {
    font-size: 1.75rem;
    padding-bottom: 0.75rem;
  }

  .reader__breadcrumb {
    font-size: 0.85rem;
    margin-bottom: 0.6rem;
  }
}