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

:root {
  --bg:            #080c18;
  --bg-card:       #111827;
  --bg-hover:      #1a2234;
  --bg-input:      #0d1525;
  --accent:        #38bdf8;
  --accent-dim:    rgba(56,189,248,0.1);
  --accent-glow:   rgba(56,189,248,0.22);
  --accent-border: rgba(56,189,248,0.28);
  --danger:        #f87171;
  --danger-dim:    rgba(248,113,113,0.12);
  --success:       #4ade80;
  --success-dim:   rgba(74,222,128,0.12);
  --warning:       #fbbf24;
  --warning-dim:   rgba(251,191,36,0.12);
  --text:          #e2e8f0;
  --text-dim:      #94a3b8;
  --text-muted:    #64748b;
  --border:        rgba(255,255,255,0.07);
  --radius:        6px;
  --radius-sm:     3px;
  --radius-lg:     10px;
  --transition:    0.18s ease;
  --shadow:        0 4px 24px rgba(0,0,0,0.5);
}

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: 'DM Sans', -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  display: flex;
  flex-direction: column;
  background-image: radial-gradient(ellipse 80% 40% at 50% -5%, rgba(56,189,248,0.07) 0%, transparent 60%);
}

.main-content { flex: 1; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* Top accent stripe */
body::before {
  content: '';
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent 0%, var(--accent) 50%, transparent 100%);
  z-index: 100;
  opacity: 0.8;
}

/* ── Header ────────────────────────────────────────────────────────────── */
.app-header {
  padding: 20px 20px 0;
  position: sticky;
  top: 2px;
  z-index: 50;
  background: rgba(8,12,24,0.9);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  max-width: 640px;
  margin: 0 auto;
  text-align: center;
}

.header-title-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.app-title {
  font-family: 'DM Serif Display', Georgia, serif;
  font-size: clamp(1.4rem, 4vw, 1.8rem);
  font-weight: 400;
  color: var(--text);
  letter-spacing: -0.3px;
  line-height: 1;
}

.level-badge {
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-dim);
  border: 1px solid var(--accent-border);
  padding: 3px 9px;
  border-radius: 20px;
}

.app-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 5px;
}

.header-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 2px;
  margin-top: 12px;
  padding-top: 4px;
  border-top: 1px solid var(--border);
}

.nav-link {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 8px 14px;
  border-radius: var(--radius);
  transition: color var(--transition), background var(--transition);
}

.nav-link:hover {
  color: var(--text);
  background: var(--bg-hover);
  text-decoration: none;
}

.nav-logout { color: var(--danger); opacity: 0.7; }
.nav-logout:hover { color: var(--danger); opacity: 1; background: var(--danger-dim); text-decoration: none; }

/* ── Flash Messages ─────────────────────────────────────────────────────── */
.flash-container {
  max-width: 540px;
  margin: 14px auto 0;
  padding: 0 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.flash {
  padding: 10px 14px;
  border-radius: var(--radius);
  font-size: 0.84rem;
  font-weight: 500;
  border-left: 3px solid;
}

.flash-error   { background: var(--danger-dim);  border-color: var(--danger);  color: #fca5a5; }
.flash-success { background: var(--success-dim); border-color: var(--success); color: #86efac; }
.flash-warning { background: var(--warning-dim); border-color: var(--warning); color: #fde68a; }
.flash-info    { background: var(--accent-dim);  border-color: var(--accent);  color: #7dd3fc; }

/* ── Tabs ───────────────────────────────────────────────────────────────── */
.tabs {
  display: flex;
  justify-content: center;
  gap: 4px;
  padding: 16px 16px 0;
  max-width: 640px;
  margin: 0 auto;
  flex-wrap: wrap;
}

.tab {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  padding: 7px 16px;
  border-radius: 20px;
  border: 1px solid var(--border);
  transition: all var(--transition);
  text-decoration: none;
}

.tab:hover {
  color: var(--text);
  border-color: var(--accent-border);
  background: var(--accent-dim);
  text-decoration: none;
}

.tab-active {
  color: var(--accent);
  background: var(--accent-dim);
  border-color: var(--accent-border);
}

/* ── Topic Chips ────────────────────────────────────────────────────────── */
.topics-section {
  max-width: 640px;
  margin: 12px auto 0;
  padding: 0 16px;
}

.topic-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.topic-chip {
  font-size: 0.73rem;
  font-weight: 500;
  padding: 4px 11px;
  border-radius: 20px;
  border: 1px solid var(--border);
  color: var(--text-muted);
  background: transparent;
  transition: all var(--transition);
  text-decoration: none;
}

.topic-chip:hover {
  border-color: var(--accent-border);
  color: var(--accent);
  background: var(--accent-dim);
  text-decoration: none;
}

.topic-chip-active {
  border-color: var(--accent-border);
  color: var(--accent);
  background: var(--accent-dim);
}

/* ── Overall Progress ───────────────────────────────────────────────────── */
.overall-progress {
  max-width: 640px;
  margin: 20px auto 0;
  padding: 0 16px;
}

.progress-bar-container {
  height: 3px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
  margin-bottom: 7px;
}

.progress-bar {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: width 0.6s ease;
  box-shadow: 0 0 8px var(--accent-glow);
}

.progress-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}

/* ── Stats Grid (Dashboard Topic Cards) ─────────────────────────────────── */
.stats-grid {
  display: grid;
  gap: 8px;
  max-width: 640px;
  margin: 16px auto 32px;
  padding: 0 16px;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px;
  display: block;
  text-decoration: none;
  transition: all var(--transition);
}

.stat-card:hover {
  border-color: var(--accent-border);
  background: var(--bg-hover);
  transform: translateX(4px);
  text-decoration: none;
}

.stat-topic {
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--text);
  margin-bottom: 6px;
}

.stat-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.stat-learned {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.stat-due {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--warning);
  background: var(--warning-dim);
  padding: 2px 8px;
  border-radius: 10px;
}

.stat-mini-bar {
  height: 2px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
}

.stat-mini-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
}

/* ── Auth (Login / Register) ────────────────────────────────────────────── */
.auth-container {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 40px 16px;
}

.auth-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  width: 100%;
  max-width: 400px;
  box-shadow: var(--shadow);
}

.auth-title {
  font-family: 'DM Serif Display', Georgia, serif;
  font-size: 1.6rem;
  font-weight: 400;
  color: var(--text);
  margin-bottom: 28px;
  letter-spacing: -0.2px;
}

.auth-form .form-group {
  margin-bottom: 18px;
}

.auth-form label {
  display: block;
  font-size: 0.73rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 7px;
}

.auth-form input {
  width: 100%;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 11px 14px;
  color: var(--text);
  font-family: 'DM Sans', sans-serif;
  font-size: 0.9rem;
  transition: border-color var(--transition), box-shadow var(--transition);
  outline: none;
}

.auth-form input::placeholder { color: var(--text-muted); opacity: 0.5; }

.auth-form input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

.auth-switch {
  text-align: center;
  margin-top: 20px;
  font-size: 0.83rem;
  color: var(--text-muted);
}

.auth-switch a { color: var(--accent); font-weight: 500; }

/* ── Buttons ────────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: 'DM Sans', sans-serif;
  font-size: 0.88rem;
  font-weight: 600;
  padding: 11px 22px;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.btn-primary {
  background: var(--accent);
  color: #050a14;
}

.btn-primary:hover {
  background: #7dd3fc;
  box-shadow: 0 0 16px var(--accent-glow);
  transform: translateY(-1px);
  color: #050a14;
  text-decoration: none;
}

.btn-full { width: 100%; }

.btn-schwer {
  background: var(--danger-dim);
  color: var(--danger);
  border: 1px solid rgba(248,113,113,0.2);
}
.btn-schwer:hover { background: rgba(248,113,113,0.2); box-shadow: 0 4px 14px rgba(248,113,113,0.2); }

.btn-okay {
  background: var(--warning-dim);
  color: var(--warning);
  border: 1px solid rgba(251,191,36,0.2);
}
.btn-okay:hover { background: rgba(251,191,36,0.2); box-shadow: 0 4px 14px rgba(251,191,36,0.2); }

.btn-leicht {
  background: var(--success-dim);
  color: var(--success);
  border: 1px solid rgba(74,222,128,0.2);
}
.btn-leicht:hover { background: rgba(74,222,128,0.2); box-shadow: 0 4px 14px rgba(74,222,128,0.2); }

/* ── Flashcard ──────────────────────────────────────────────────────────── */
.session-info {
  max-width: 540px;
  margin: 20px auto 6px;
  padding: 0 16px;
}

.session-topic {
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
}

.card-counter {
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin: 8px auto;
  font-weight: 500;
}

.dot-progress {
  display: flex;
  justify-content: center;
  gap: 6px;
  margin: 10px auto 16px;
}

.dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--border);
  transition: background var(--transition), transform var(--transition);
}

.dot-active {
  background: var(--accent);
  transform: scale(1.3);
  box-shadow: 0 0 6px var(--accent-glow);
}

.card-stack {
  max-width: 520px;
  margin: 0 auto;
  padding: 0 16px;
}

.flashcard {
  width: 100%;
  height: 230px;
  position: relative;
  margin-bottom: 14px;
  cursor: pointer;
  perspective: 900px;
}

.flashcard-hidden { display: none; }

.flashcard.is-exiting {
  animation: cardExit 0.26s ease forwards;
}

@keyframes cardExit {
  to { opacity: 0; transform: translateY(-12px) scale(0.97); }
}

.flashcard-inner {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s cubic-bezier(0.4,0,0.2,1);
}

.flashcard-inner.is-flipped { transform: rotateY(180deg); }

.flashcard-front,
.flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  overflow-y: auto;
}

.flashcard-back {
  transform: rotateY(180deg);
  border-color: var(--accent-border);
}

.card-label {
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.card-label-c1 { color: var(--accent); }

.card-sentence {
  font-size: 0.95rem;
  color: var(--text-dim);
  line-height: 1.65;
  font-style: italic;
}

.card-hint {
  margin-top: 12px;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.card-c1-word {
  margin-top: 12px;
  font-size: 0.88rem;
  color: var(--text-dim);
  font-weight: 500;
}

.card-explanation {
  margin-top: 12px;
  font-size: 0.8rem;
  color: var(--text-muted);
  background: var(--accent-dim);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius);
  padding: 10px 14px;
  line-height: 1.55;
}

.highlight      { background: rgba(251,191,36,0.2); color: var(--warning); padding: 0 2px; border-radius: 2px; font-style: normal; }
.highlight-c1   { background: var(--accent-dim);    color: var(--accent);  padding: 0 2px; border-radius: 2px; font-style: normal; }

.flip-hint {
  text-align: center;
  font-size: 0.73rem;
  color: var(--text-muted);
  margin-top: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.key-badge {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1px 7px;
  font-size: 0.68rem;
  color: var(--text-muted);
  font-family: monospace;
}

.rating-buttons {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 10px;
  max-width: 520px;
  margin: 0 auto 16px;
  padding: 0 16px;
}

.rating-buttons .btn {
  padding: 12px 8px;
  flex-direction: column;
  gap: 2px;
  font-size: 0.82rem;
}

.key-hint {
  font-size: 0.65rem;
  opacity: 0.6;
  font-family: monospace;
  border: 1px solid currentColor;
  border-radius: 3px;
  padding: 0px 4px;
  line-height: 1.4;
}

.swipe-hint {
  display: flex;
  justify-content: space-between;
  max-width: 520px;
  margin: 0 auto 24px;
  padding: 0 20px;
  font-size: 0.73rem;
  color: var(--text-muted);
  opacity: 0.6;
}

/* ── Done Box ───────────────────────────────────────────────────────────── */
.done-box {
  max-width: 440px;
  margin: 40px auto;
  padding: 0 16px;
  text-align: center;
  background: var(--bg-card);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  box-shadow: 0 0 30px var(--accent-glow);
}

.done-icon { font-size: 2.5rem; margin-bottom: 14px; }

.done-box h2 {
  font-family: 'DM Serif Display', Georgia, serif;
  font-size: 1.5rem;
  color: var(--text);
  margin-bottom: 10px;
}

.done-box p {
  color: var(--text-muted);
  font-size: 0.88rem;
  margin-bottom: 8px;
}

.done-box .btn { margin-top: 16px; }

/* ── Quiz / Tippen / Lückentext / Zuordnung ─────────────────────────────── */
.quiz-container,
.tippen-container,
.lueckentext-container,
.zuordnung-container {
  max-width: 540px;
  margin: 24px auto;
  padding: 0 16px;
}

.question-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-bottom: 14px;
}

.question-card h3,
.question-card .question-text {
  font-size: 0.95rem;
  color: var(--text-dim);
  line-height: 1.65;
  margin-bottom: 18px;
  font-style: italic;
}

.options-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.option-btn {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 16px;
  font-size: 0.88rem;
  color: var(--text-dim);
  cursor: pointer;
  transition: all var(--transition);
  text-align: left;
  font-family: 'DM Sans', sans-serif;
  width: 100%;
}

.option-btn:hover { border-color: var(--accent-border); color: var(--text); background: var(--accent-dim); }
.option-btn.correct { border-color: var(--success); background: var(--success-dim); color: var(--success); }
.option-btn.wrong   { border-color: var(--danger);  background: var(--danger-dim);  color: var(--danger); }

.input-row {
  display: flex;
  gap: 8px;
}

.input-row input {
  flex: 1;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 11px 14px;
  color: var(--text);
  font-family: 'DM Sans', sans-serif;
  font-size: 0.9rem;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.input-row input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

.feedback-correct { color: var(--success); font-weight: 600; font-size: 0.85rem; margin-top: 10px; }
.feedback-wrong   { color: var(--danger);  font-weight: 600; font-size: 0.85rem; margin-top: 10px; }

.match-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.match-item {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 14px;
  font-size: 0.84rem;
  color: var(--text-dim);
  cursor: pointer;
  transition: all var(--transition);
  text-align: center;
}

.match-item:hover     { border-color: var(--accent-border); color: var(--text); }
.match-item.selected  { border-color: var(--accent); background: var(--accent-dim); color: var(--accent); }
.match-item.matched   { border-color: var(--success); background: var(--success-dim); color: var(--success); pointer-events: none; }
.match-item.mismatch  { border-color: var(--danger);  background: var(--danger-dim);  color: var(--danger); }

.score-summary {
  text-align: center;
  padding: 40px 24px;
  color: var(--text-muted);
}

.score-summary .big-score {
  font-family: 'DM Serif Display', serif;
  font-size: 4rem;
  color: var(--accent);
  line-height: 1;
  display: block;
}

/* ── Footer ─────────────────────────────────────────────────────────────── */
.app-footer {
  text-align: center;
  padding: 20px 16px;
  border-top: 1px solid var(--border);
  font-size: 0.78rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  margin-top: 40px;
}

.app-footer a {
  color: var(--text-muted);
  text-decoration: none;
  padding: 0 12px;
  transition: color var(--transition);
}

.app-footer a:hover { color: var(--accent); }
.app-footer span { color: var(--border); user-select: none; }

/* ── Legal Pages ────────────────────────────────────────────────────────── */
.legal-page {
  max-width: 680px;
  margin: 32px auto;
  padding: 0 16px 40px;
  line-height: 1.75;
  color: var(--text-dim);
}

.legal-page h2 {
  font-family: 'DM Serif Display', serif;
  font-size: 1.7rem;
  font-weight: 400;
  margin-bottom: 28px;
  color: var(--text);
}

.legal-page h3 {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-top: 32px;
  margin-bottom: 10px;
  color: var(--accent);
}

.legal-page ul { padding-left: 18px; margin: 8px 0; }
.legal-page li { margin-bottom: 6px; }
.legal-page a  { color: var(--accent); }

.back-link {
  display: inline-block;
  margin-top: 36px;
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text-muted);
  transition: color var(--transition);
}

.back-link:hover { color: var(--accent); text-decoration: none; }

/* ── Responsive ─────────────────────────────────────────────────────────── */
@media (max-width: 520px) {
  .auth-card { padding: 28px 20px; }
  .rating-buttons { grid-template-columns: 1fr; }
  .match-grid { grid-template-columns: 1fr; }
  .tabs { gap: 4px; }
}

@media (min-width: 640px) {
  .stats-grid { grid-template-columns: 1fr 1fr; }
}