/* ============================================================
   assets/css/style.css – Zentrales Design-System
   lernbuch.schule
   ============================================================ */

/* ── Lokale Schriften (DSGVO-konform, kein Google) ────────── */

/* Lexend – Fließtext & UI */
@font-face {
  font-family: 'Lexend';
  src: url('../fonts/lexend-400.woff2') format('woff2');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Lexend';
  src: url('../fonts/lexend-500.woff2') format('woff2');
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Lexend';
  src: url('../fonts/lexend-600.woff2') format('woff2');
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Lexend';
  src: url('../fonts/lexend-700.woff2') format('woff2');
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Lexend';
  src: url('../fonts/lexend-800.woff2') format('woff2');
  font-weight: 800;
  font-style: normal;
  font-display: swap;
}

/* Source Serif 4 – Überschriften */
@font-face {
  font-family: 'Source Serif 4';
  src: url('../fonts/source-serif-4-300.woff2') format('woff2');
  font-weight: 300;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Source Serif 4';
  src: url('../fonts/source-serif-4-300italic.woff2') format('woff2');
  font-weight: 300;
  font-style: italic;
  font-display: swap;
}
@font-face {
  font-family: 'Source Serif 4';
  src: url('../fonts/source-serif-4-400.woff2') format('woff2');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Source Serif 4';
  src: url('../fonts/source-serif-4-600.woff2') format('woff2');
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: 'Source Serif 4';
  src: url('../fonts/source-serif-4-600italic.woff2') format('woff2');
  font-weight: 600;
  font-style: italic;
  font-display: swap;
}

/* ── CSS Custom Properties ────────────────────────────────── */
:root {
  /* Farben */
  --sl-bg:            #F8F9FB;
  --sl-surface:       #FFFFFF;
  --sl-border:        rgba(0,0,0,0.08);
  --sl-primary:       #4A7FCB;
  --sl-primary-light: #EAF1FB;
  --sl-primary-dark:  #2D5A9E;
  --sl-accent:        #3BAF7E;
  --sl-accent-light:  #E6F7F0;
  --sl-warn:          #E8A020;
  --sl-warn-light:    #FEF5E4;
  --sl-text:          #1A1A2E;
  --sl-muted:         #6B7280;
  --sl-subtle:        #9CA3AF;

  /* Fach-Farben */
  --fach-mathe:       #4A7FCB;
  --fach-deutsch:     #3BAF7E;
  --fach-nawi:        #E8A020;
  --fach-musik:       #B06ECB;
  --fach-kunst:       #E06070;
  --fach-physik:      #5BAFD6;
  --fach-sport:       #6B8E5E;
  --fach-ethik:       #D4835A;
  --fach-wat:         #4A7FCB;
  --fach-geo:         #3BAF7E;
  --fach-sprachen:    #B06ECB;
  --fach-geschichte:  #D4835A;

  /* Radien */
  --sl-radius:    10px;
  --sl-radius-sm: 6px;
  --sl-radius-lg: 16px;

  /* Schatten */
  --sl-shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --sl-shadow:    0 4px 12px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
  --sl-shadow-lg: 0 8px 24px rgba(0,0,0,0.10), 0 4px 8px rgba(0,0,0,0.06);

  /* Übergänge */
  --sl-transition: 0.18s ease;
}

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

html {
  font-size: 15px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: 'Lexend', system-ui, sans-serif;
  background-color: var(--sl-bg);
  color: var(--sl-text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--sl-primary);
  text-decoration: none;
  transition: color var(--sl-transition);
}
a:hover { color: var(--sl-primary-dark); }

img { max-width: 100%; height: auto; display: block; }

/* ── Layout ───────────────────────────────────────────────── */
.sl-container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
}

.sl-main {
  flex: 1;
  padding: 32px 0 64px;
}

/* ── Navigation ───────────────────────────────────────────── */
.sl-nav {
  background: var(--sl-surface);
  border-bottom: 1px solid var(--sl-border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--sl-shadow-sm);
}

.sl-nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  gap: 16px;
}

.sl-nav__logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: 'Source Serif 4', serif;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--sl-primary-dark);
  text-decoration: none;
  flex-shrink: 0;
}

.sl-nav__logo-icon {
  width: 34px;
  height: 34px;
  background: linear-gradient(135deg, var(--sl-primary), var(--sl-primary-dark));
  border-radius: var(--sl-radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1rem;
}

.sl-nav__links {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
}

.sl-nav__links a {
  padding: 6px 12px;
  border-radius: var(--sl-radius-sm);
  color: var(--sl-muted);
  font-weight: 500;
  font-size: 0.875rem;
  transition: all var(--sl-transition);
}
.sl-nav__links a:hover,
.sl-nav__links a.aktiv {
  background: var(--sl-primary-light);
  color: var(--sl-primary-dark);
}

.sl-nav__actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* ── Buttons ──────────────────────────────────────────────── */
.sl-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border-radius: var(--sl-radius-sm);
  font-family: 'Lexend', sans-serif;
  font-size: 0.875rem;
  font-weight: 700;
  cursor: pointer;
  border: none;
  transition: all var(--sl-transition);
  text-decoration: none;
  line-height: 1;
}

.sl-btn--primary {
  background: var(--sl-primary);
  color: white;
}
.sl-btn--primary:hover {
  background: var(--sl-primary-dark);
  color: white;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(74,127,203,0.35);
}

.sl-btn--secondary {
  background: var(--sl-primary-light);
  color: var(--sl-primary-dark);
}
.sl-btn--secondary:hover {
  background: #d4e5f7;
  color: var(--sl-primary-dark);
}

.sl-btn--ghost {
  background: transparent;
  color: var(--sl-muted);
  border: 1px solid var(--sl-border);
}
.sl-btn--ghost:hover {
  background: var(--sl-bg);
  color: var(--sl-text);
}

.sl-btn--lg {
  padding: 12px 28px;
  font-size: 1rem;
  border-radius: var(--sl-radius);
}

.sl-btn--sm {
  padding: 5px 12px;
  font-size: 0.8rem;
}

/* ── Karten ───────────────────────────────────────────────── */
.sl-card {
  background: var(--sl-surface);
  border: 1px solid var(--sl-border);
  border-radius: var(--sl-radius);
  padding: 20px;
  box-shadow: var(--sl-shadow-sm);
  transition: box-shadow var(--sl-transition), transform var(--sl-transition);
}

.sl-card:hover {
  box-shadow: var(--sl-shadow);
  transform: translateY(-2px);
}

.sl-card--flat { box-shadow: none; }
.sl-card--flat:hover { box-shadow: none; transform: none; }

/* ── Badges ───────────────────────────────────────────────── */
.sl-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.sl-badge--primary { background: var(--sl-primary-light); color: var(--sl-primary-dark); }
.sl-badge--accent  { background: var(--sl-accent-light);  color: #1a7a53; }
.sl-badge--warn    { background: var(--sl-warn-light);    color: #9a6a10; }
.sl-badge--muted   { background: var(--sl-bg);            color: var(--sl-muted); border: 1px solid var(--sl-border); }

/* ── Fortschrittsbalken ───────────────────────────────────── */
.sl-progress {
  width: 100%;
  height: 6px;
  background: var(--sl-bg);
  border-radius: 3px;
  overflow: hidden;
}

.sl-progress__bar {
  height: 100%;
  background: linear-gradient(90deg, var(--sl-primary), var(--sl-accent));
  border-radius: 3px;
  transition: width 0.4s ease;
}

/* ── Formulare ────────────────────────────────────────────── */
.sl-form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 16px;
}

.sl-label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--sl-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.sl-input,
.sl-select,
.sl-textarea {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--sl-border);
  border-radius: var(--sl-radius-sm);
  font-family: 'Lexend', sans-serif;
  font-size: 0.9375rem;
  color: var(--sl-text);
  background: var(--sl-surface);
  transition: border-color var(--sl-transition), box-shadow var(--sl-transition);
  outline: none;
}

.sl-input:focus,
.sl-select:focus,
.sl-textarea:focus {
  border-color: var(--sl-primary);
  box-shadow: 0 0 0 3px rgba(74,127,203,0.15);
}

.sl-textarea { resize: vertical; min-height: 100px; }

/* ── Alerts & Hinweise ────────────────────────────────────── */
.sl-alert {
  padding: 12px 16px;
  border-radius: var(--sl-radius-sm);
  font-size: 0.875rem;
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 16px;
}

.sl-alert--info    { background: var(--sl-primary-light); color: var(--sl-primary-dark); }
.sl-alert--success { background: var(--sl-accent-light);  color: #1a7a53; }
.sl-alert--warn    { background: var(--sl-warn-light);    color: #9a6a10; }
.sl-alert--error   { background: #FEF0F0; color: #9b2626; }

/* ── Quiz-Komponenten ─────────────────────────────────────── */
.sl-quiz-option {
  display: block;
  width: 100%;
  text-align: left;
  padding: 12px 16px;
  border: 1.5px solid var(--sl-border);
  border-radius: var(--sl-radius-sm);
  background: var(--sl-surface);
  font-family: 'Lexend', sans-serif;
  font-size: 0.9375rem;
  cursor: pointer;
  transition: all var(--sl-transition);
  margin-bottom: 8px;
  color: var(--sl-text);
}

.sl-quiz-option:hover:not(:disabled) {
  border-color: var(--sl-primary);
  background: var(--sl-primary-light);
}

.sl-quiz-option.richtig {
  background: var(--sl-accent-light);
  border-color: var(--sl-accent);
  color: #1a7a53;
  font-weight: 600;
}

.sl-quiz-option.falsch {
  background: #FEF0F0;
  border-color: #FFADAD;
  color: #9b2626;
}

/* ── Fach-Farb-Hilfklassen ────────────────────────────────── */
.fach-mathe     { --fach-color: var(--fach-mathe); }
.fach-deutsch   { --fach-color: var(--fach-deutsch); }
.fach-nawi      { --fach-color: var(--fach-nawi); }
.fach-musik     { --fach-color: var(--fach-musik); }
.fach-kunst     { --fach-color: var(--fach-kunst); }
.fach-physik    { --fach-color: var(--fach-physik); }
.fach-sport     { --fach-color: var(--fach-sport); }
.fach-ethik     { --fach-color: var(--fach-ethik); }
.fach-wat       { --fach-color: var(--fach-wat); }
.fach-geo       { --fach-color: var(--fach-geo); }
.fach-sprachen  { --fach-color: var(--fach-sprachen); }
.fach-geschichte{ --fach-color: var(--fach-geschichte); }

.fach-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: var(--fach-color, var(--sl-primary));
  display: inline-block;
  flex-shrink: 0;
}

/* ── Seitenüberschrift ────────────────────────────────────── */
.sl-page-header {
  padding: 40px 0 32px;
}

.sl-page-header h1 {
  font-family: 'Source Serif 4', serif;
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  color: var(--sl-text);
  line-height: 1.2;
}

.sl-page-header p {
  color: var(--sl-muted);
  font-size: 1rem;
  margin-top: 8px;
}

/* ── Grid-System ──────────────────────────────────────────── */
.sl-grid {
  display: grid;
  gap: 16px;
}

.sl-grid--2 { grid-template-columns: repeat(2, 1fr); }
.sl-grid--3 { grid-template-columns: repeat(3, 1fr); }
.sl-grid--4 { grid-template-columns: repeat(4, 1fr); }
.sl-grid--auto { grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }

/* ── Trennlinie ───────────────────────────────────────────── */
.sl-divider {
  height: 1px;
  background: var(--sl-border);
  margin: 24px 0;
}

/* ── Tabellen ─────────────────────────────────────────────── */
.sl-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.sl-table th {
  text-align: left;
  padding: 10px 14px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--sl-muted);
  border-bottom: 1px solid var(--sl-border);
}

.sl-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--sl-border);
  vertical-align: middle;
}

.sl-table tr:last-child td { border-bottom: none; }
.sl-table tr:hover td { background: var(--sl-bg); }

/* ── Footer ───────────────────────────────────────────────── */
.sl-footer {
  background: var(--sl-surface);
  border-top: 1px solid var(--sl-border);
  padding: 28px 0;
  margin-top: auto;
  font-size: 0.825rem;
  color: var(--sl-muted);
}

.sl-footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.sl-footer__links {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.sl-footer__links a {
  color: var(--sl-muted);
  font-size: 0.825rem;
}
.sl-footer__links a:hover { color: var(--sl-primary); }

/* ── Hero (Startseite) ────────────────────────────────────── */
.sl-hero {
  background: linear-gradient(135deg, var(--sl-primary-dark) 0%, var(--sl-primary) 60%, #5B9FE0 100%);
  color: white;
  padding: 72px 0 80px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.sl-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.04'%3E%3Ccircle cx='30' cy='30' r='2'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.sl-hero__content { position: relative; z-index: 1; }

.sl-hero h1 {
  font-family: 'Source Serif 4', serif;
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.15;
  margin-bottom: 16px;
}

.sl-hero p {
  font-size: clamp(1rem, 2.5vw, 1.2rem);
  opacity: 0.88;
  max-width: 560px;
  margin: 0 auto 32px;
  line-height: 1.65;
}

.sl-hero__actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.sl-btn--hero {
  padding: 14px 32px;
  font-size: 1.05rem;
  border-radius: var(--sl-radius);
  background: white;
  color: var(--sl-primary-dark);
  font-weight: 800;
}
.sl-btn--hero:hover {
  background: #f0f4ff;
  color: var(--sl-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.25);
}

.sl-btn--hero-outline {
  padding: 14px 32px;
  font-size: 1.05rem;
  border-radius: var(--sl-radius);
  background: rgba(255,255,255,0.12);
  color: white;
  border: 1.5px solid rgba(255,255,255,0.4);
  font-weight: 700;
}
.sl-btn--hero-outline:hover {
  background: rgba(255,255,255,0.22);
  color: white;
  transform: translateY(-2px);
}

/* ── Fach-Karte ───────────────────────────────────────────── */
.sl-fach-karte {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px;
  border-radius: var(--sl-radius);
  background: var(--sl-surface);
  border: 1px solid var(--sl-border);
  text-decoration: none;
  color: var(--sl-text);
  transition: all var(--sl-transition);
  position: relative;
  overflow: hidden;
}

.sl-fach-karte::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--fach-color, var(--sl-primary));
}

.sl-fach-karte:hover {
  box-shadow: var(--sl-shadow);
  transform: translateY(-3px);
  color: var(--sl-text);
  border-color: transparent;
}

.sl-fach-karte__icon {
  width: 44px; height: 44px;
  border-radius: var(--sl-radius-sm);
  background: var(--sl-bg);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.375rem;
}

.sl-fach-karte__name {
  font-weight: 700;
  font-size: 0.9375rem;
  color: var(--sl-text);
}

.sl-fach-karte__lektionen {
  font-size: 0.8rem;
  color: var(--sl-muted);
}

/* ── Breadcrumb ───────────────────────────────────────────── */
.sl-breadcrumb {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  color: var(--sl-muted);
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.sl-breadcrumb a {
  color: var(--sl-muted);
}
.sl-breadcrumb a:hover { color: var(--sl-primary); }

.sl-breadcrumb__sep { color: var(--sl-subtle); }

/* ── Lektion-Layout ───────────────────────────────────────── */
.sl-lektion-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 24px;
  align-items: start;
}

.sl-lektion-inhalt {
  background: var(--sl-surface);
  border: 1px solid var(--sl-border);
  border-radius: var(--sl-radius);
  padding: 32px;
}

.sl-lektion-inhalt h2 {
  font-family: 'Source Serif 4', serif;
  font-size: 1.5rem;
  margin-bottom: 16px;
  color: var(--sl-text);
}

.sl-lektion-inhalt h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 24px 0 10px;
  color: var(--sl-text);
}

.sl-lektion-inhalt p {
  margin-bottom: 14px;
  line-height: 1.75;
}

.sl-lektion-inhalt ul,
.sl-lektion-inhalt ol {
  padding-left: 22px;
  margin-bottom: 14px;
}

.sl-lektion-inhalt li {
  margin-bottom: 6px;
  line-height: 1.65;
}

.sl-lektion-sidebar {
  display: flex;
  flex-direction: column;
  gap: 16px;
  position: sticky;
  top: 76px;
}

/* ── Infobox ──────────────────────────────────────────────── */
.sl-infobox {
  border-left: 3px solid var(--sl-primary);
  background: var(--sl-primary-light);
  border-radius: 0 var(--sl-radius-sm) var(--sl-radius-sm) 0;
  padding: 14px 16px;
  font-size: 0.9rem;
  margin: 20px 0;
}

.sl-infobox--accent {
  border-color: var(--sl-accent);
  background: var(--sl-accent-light);
}

.sl-infobox--warn {
  border-color: var(--sl-warn);
  background: var(--sl-warn-light);
}

/* ── Responsive ───────────────────────────────────────────── */
@media (max-width: 900px) {
  .sl-lektion-layout {
    grid-template-columns: 1fr;
  }
  .sl-lektion-sidebar {
    position: static;
  }
  .sl-grid--3, .sl-grid--4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 600px) {
  .sl-container { padding: 0 16px; }
  .sl-nav__links { display: none; }
  .sl-grid--2, .sl-grid--3, .sl-grid--4 {
    grid-template-columns: 1fr;
  }
  .sl-hero { padding: 48px 0 56px; }
  .sl-hero__actions { flex-direction: column; align-items: center; }
  .sl-footer__inner { flex-direction: column; align-items: flex-start; }
  .sl-lektion-inhalt { padding: 20px 16px; }
}

/* ── Utility ──────────────────────────────────────────────── */
.sl-text-muted   { color: var(--sl-muted); }
.sl-text-subtle  { color: var(--sl-subtle); }
.sl-text-primary { color: var(--sl-primary); }
.sl-text-accent  { color: var(--sl-accent); }
.sl-text-sm      { font-size: 0.85rem; }
.sl-text-xs      { font-size: 0.75rem; }
.sl-fw-bold      { font-weight: 700; }
.sl-fw-medium    { font-weight: 500; }
.sl-mt-0  { margin-top: 0; }
.sl-mt-8  { margin-top: 8px; }
.sl-mt-16 { margin-top: 16px; }
.sl-mt-24 { margin-top: 24px; }
.sl-mb-0  { margin-bottom: 0; }
.sl-mb-8  { margin-bottom: 8px; }
.sl-mb-16 { margin-bottom: 16px; }
.sl-mb-24 { margin-bottom: 24px; }
.sl-flex  { display: flex; }
.sl-flex-center { display: flex; align-items: center; }
.sl-gap-8  { gap: 8px; }
.sl-gap-16 { gap: 16px; }
.sl-gap-24 { gap: 24px; }
.sl-hidden { display: none; }

/* ── Kopierschutz – Frontend-Hinweise ─────────────────────── */
.sl-copy-protected {
  user-select: none;
  -webkit-user-select: none;
}