/* ============================
   Variables & Reset
   ============================ */
:root {
  --bg:        #0f172a;
  --bg-card:   #1e293b;
  --bg-card2:  #263349;
  --bg-input:  #0f1f33;
  --border:    #334155;
  --accent:    #3b82f6;
  --accent-d:  #2563eb;
  --success:   #22c55e;
  --warning:   #f59e0b;
  --danger:    #ef4444;
  --danger-d:  #dc2626;
  --text:      #f1f5f9;
  --text-muted:#94a3b8;
  --text-dim:  #64748b;
  --radius:    12px;
  --radius-sm: 8px;
  --shadow:    0 4px 24px rgba(0,0,0,0.4);
  --header-h:  56px;
  --transition:0.2s ease;
}
*,*::before,*::after { box-sizing:border-box; margin:0; padding:0; }
html { font-size:16px; -webkit-text-size-adjust:100%; }
body {
  font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;
  background:var(--bg);
  color:var(--text);
  min-height:100vh;
  overflow-x:hidden;
  line-height:1.5;
}
button { cursor:pointer; font:inherit; border:none; background:none; }
input,textarea,select { font:inherit; color:var(--text); }
a { color:var(--accent); text-decoration:none; }
ul { list-style:none; }
img { max-width:100%; }

/* ============================
   Login Page
   ============================ */
#login-page {
  min-height:100vh;
  display:flex;
  align-items:center;
  justify-content:center;
  padding:24px 16px;
  background:radial-gradient(ellipse at top, #1e3a5f 0%, var(--bg) 70%);
}
.login-container {
  width:100%;
  max-width:380px;
}
.login-logo {
  text-align:center;
  margin-bottom:32px;
}
.login-logo .logo-icon {
  font-size:48px;
  display:block;
  margin-bottom:12px;
}
.login-logo h1 {
  font-size:28px;
  font-weight:700;
  letter-spacing:-0.5px;
}
.login-logo p {
  color:var(--text-muted);
  margin-top:4px;
  font-size:14px;
}
.login-form {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:24px;
  display:flex;
  flex-direction:column;
  gap:16px;
}
.alert {
  padding:12px 16px;
  border-radius:var(--radius-sm);
  font-size:14px;
  margin-bottom:8px;
}
.alert-error {
  background:rgba(239,68,68,0.15);
  border:1px solid rgba(239,68,68,0.3);
  color:#fca5a5;
}

/* ============================
   App Layout
   ============================ */
#app {
  min-height:100vh;
}
#app-header {
  position:fixed;
  top:0; left:0; right:0;
  height:var(--header-h);
  background:rgba(15,23,42,0.95);
  backdrop-filter:blur(12px);
  border-bottom:1px solid var(--border);
  display:flex;
  align-items:center;
  gap:12px;
  padding:0 16px;
  z-index:100;
}
#header-title {
  flex:1;
  font-size:17px;
  font-weight:600;
  overflow:hidden;
  text-overflow:ellipsis;
  white-space:nowrap;
}
#header-right {
  display:flex;
  align-items:center;
  gap:8px;
}
#main {
  position:fixed;
  top:var(--header-h);
  left:0; right:0; bottom:0;
  overflow:hidden;
}

/* ============================
   Views
   ============================ */
.view {
  position:absolute;
  top:0; left:0; right:0; bottom:0;
  overflow-y:auto;
  -webkit-overflow-scrolling:touch;
  padding:16px 16px 88px;
  transform:translateX(100%);
  transition:transform 0.3s cubic-bezier(0.4,0,0.2,1);
  will-change:transform;
}
.view.active {
  transform:translateX(0);
}
.view.slide-left {
  transform:translateX(-100%);
}

/* ============================
   Buttons
   ============================ */
.btn {
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:12px 20px;
  border-radius:var(--radius-sm);
  font-size:15px;
  font-weight:500;
  transition:background var(--transition), transform 0.1s;
  white-space:nowrap;
}
.btn:active { transform:scale(0.97); }
.btn-primary {
  background:var(--accent);
  color:#fff;
}
.btn-primary:hover { background:var(--accent-d); }
.btn-secondary {
  background:var(--bg-card2);
  color:var(--text);
  border:1px solid var(--border);
}
.btn-secondary:hover { background:#2e3e52; }
.btn-danger {
  background:var(--danger);
  color:#fff;
}
.btn-danger:hover { background:var(--danger-d); }
.btn-full { width:100%; }
.btn-icon {
  width:40px; height:40px;
  display:flex; align-items:center; justify-content:center;
  border-radius:50%;
  color:var(--text);
  font-size:20px;
  transition:background var(--transition);
  flex-shrink:0;
}
.btn-icon:hover { background:var(--bg-card2); }
.btn-text {
  color:var(--accent);
  font-size:14px;
  padding:4px 8px;
}
.btn-close {
  width:32px; height:32px;
  display:flex; align-items:center; justify-content:center;
  border-radius:50%;
  color:var(--text-muted);
  font-size:18px;
  transition:background var(--transition);
}
.btn-close:hover { background:var(--bg-card2); color:var(--text); }

.btn-star {
  font-size:24px;
  color:var(--text-dim);
  transition:color var(--transition), transform 0.2s;
  padding:4px 8px;
}
.btn-star.starred { color:var(--warning); }
.btn-star:active { transform:scale(1.3); }

.btn-fab {
  position:fixed;
  bottom:24px; right:20px;
  width:56px; height:56px;
  border-radius:50%;
  font-size:28px;
  background:var(--accent);
  color:#fff;
  box-shadow:0 4px 16px rgba(59,130,246,0.4);
  z-index:50;
  padding:0;
}

/* ============================
   Inputs & Forms
   ============================ */
.input-group {
  display:flex;
  flex-direction:column;
  gap:6px;
}
.input-group label {
  font-size:14px;
  font-weight:500;
  color:var(--text-muted);
}
input[type="text"],
input[type="password"],
input[type="number"],
textarea,
select {
  background:var(--bg-input);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  padding:12px 14px;
  font-size:15px;
  color:var(--text);
  width:100%;
  transition:border-color var(--transition);
  -webkit-appearance:none;
}
input:focus, textarea:focus, select:focus {
  outline:none;
  border-color:var(--accent);
}
textarea {
  resize:vertical;
  min-height:120px;
  line-height:1.6;
}
input[type="number"] { max-width:120px; }

/* ============================
   Cards & Sections
   ============================ */
.card {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:16px;
}
.section {
  display:flex;
  flex-direction:column;
  gap:16px;
  padding-bottom:8px;
}
.section h3 {
  font-size:17px;
  font-weight:600;
}
.section-desc {
  font-size:14px;
  color:var(--text-muted);
  margin-top:-8px;
}
.section-sub {
  display:flex;
  flex-direction:column;
  gap:10px;
}
.section-sub h4 {
  font-size:15px;
  font-weight:600;
  color:var(--text-muted);
}

/* ============================
   Dashboard
   ============================ */
.dashboard-hero {
  margin-bottom:20px;
}
.dashboard-hero h2 {
  font-size:22px;
  font-weight:700;
}
.dashboard-hero p {
  color:var(--text-muted);
  font-size:14px;
  margin-top:4px;
}
.modules-grid {
  display:grid;
  grid-template-columns:repeat(auto-fill, minmax(155px, 1fr));
  gap:12px;
}
.module-card {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:16px 14px;
  cursor:pointer;
  transition:border-color var(--transition), transform 0.15s;
  position:relative;
  min-height:130px;
  display:flex;
  flex-direction:column;
  gap:10px;
}
.module-card:hover { border-color:var(--accent); }
.module-card:active { transform:scale(0.97); }
.module-card-name {
  font-size:14px;
  font-weight:600;
  line-height:1.3;
  flex:1;
}
.module-card-progress {
  display:flex;
  gap:6px;
  flex-wrap:wrap;
}
.progress-chip {
  font-size:11px;
  padding:3px 8px;
  border-radius:20px;
  background:var(--bg-card2);
  color:var(--text-muted);
  white-space:nowrap;
}
.progress-chip.has-content { color:var(--accent); background:rgba(59,130,246,0.12); }
.module-card-date {
  font-size:11px;
  color:var(--text-dim);
}

.empty-state {
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  text-align:center;
  padding:48px 24px;
  gap:12px;
}
.empty-icon { font-size:48px; }
.empty-state h3 { font-size:18px; font-weight:600; }
.empty-state p { font-size:14px; color:var(--text-muted); max-width:280px; }

/* ============================
   Tab Bar
   ============================ */
.tab-bar {
  display:flex;
  border-bottom:1px solid var(--border);
  margin: 0 -16px;
  padding:0 16px;
  gap:0;
  position:sticky;
  top:0;
  background:var(--bg);
  z-index:10;
}
.tab-btn {
  flex:1;
  padding:12px 8px;
  font-size:13px;
  font-weight:500;
  color:var(--text-muted);
  border-bottom:2px solid transparent;
  transition:color var(--transition), border-color var(--transition);
  text-align:center;
}
.tab-btn.active {
  color:var(--accent);
  border-bottom-color:var(--accent);
}
.tab-content { padding-top:16px; }
.tab-content.hidden { display:none; }

/* ============================
   Upload Area
   ============================ */
.upload-area {
  position:relative;
}
.file-input {
  position:absolute;
  inset:0;
  opacity:0;
  cursor:pointer;
  z-index:1;
}
.upload-label {
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:6px;
  padding:20px;
  border:2px dashed var(--border);
  border-radius:var(--radius);
  background:var(--bg-input);
  cursor:pointer;
  transition:border-color var(--transition), background var(--transition);
  text-align:center;
}
.upload-label:hover { border-color:var(--accent); background:rgba(59,130,246,0.05); }
.upload-icon { font-size:28px; }
.upload-label span:nth-child(2) { font-size:15px; font-weight:500; }
.upload-hint { font-size:12px; color:var(--text-muted); }

.file-list { display:flex; flex-direction:column; gap:8px; margin-top:8px; }
.file-item {
  display:flex;
  align-items:center;
  gap:10px;
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  padding:10px 12px;
}
.file-item-name { flex:1; font-size:14px; overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }
.file-item-size { font-size:12px; color:var(--text-muted); flex-shrink:0; }
.file-item-remove {
  width:28px; height:28px;
  border-radius:50%;
  display:flex; align-items:center; justify-content:center;
  color:var(--text-dim);
  font-size:16px;
  flex-shrink:0;
  transition:color var(--transition), background var(--transition);
}
.file-item-remove:hover { color:var(--danger); background:rgba(239,68,68,0.1); }

.text-preview {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  overflow:hidden;
}
.preview-header {
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:10px 14px;
  font-size:14px;
  color:var(--text-muted);
}
.preview-content {
  padding:14px;
  font-size:12px;
  color:var(--text-muted);
  white-space:pre-wrap;
  max-height:200px;
  overflow-y:auto;
  border-top:1px solid var(--border);
  line-height:1.6;
}
.preview-content.hidden { display:none; }

/* ============================
   Materialien Tab
   ============================ */
.stats-grid {
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:10px;
  margin-bottom:16px;
}
.stat-card {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  padding:14px 12px;
  text-align:center;
  display:flex;
  flex-direction:column;
  gap:4px;
}
.stat-number {
  font-size:26px;
  font-weight:700;
  color:var(--accent);
}
.stat-label { font-size:11px; color:var(--text-muted); }
.action-row {
  display:flex;
  flex-direction:column;
  gap:8px;
  margin-bottom:20px;
}
.content-preview-item {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  padding:12px 14px;
  margin-bottom:8px;
}
.content-preview-q { font-size:14px; font-weight:500; margin-bottom:4px; }
.content-preview-a { font-size:13px; color:var(--text-muted); }

/* ============================
   Learn Setup
   ============================ */
.setup-container {
  max-width:440px;
  margin:0 auto;
}
.setup-container h2 {
  font-size:22px;
  font-weight:700;
  margin-bottom:20px;
}
.mode-cards {
  display:flex;
  flex-direction:column;
  gap:12px;
  margin-bottom:24px;
}
.mode-card {
  background:var(--bg-card);
  border:2px solid var(--border);
  border-radius:var(--radius);
  padding:16px 18px;
  cursor:pointer;
  display:flex;
  align-items:center;
  gap:14px;
  transition:border-color var(--transition), background var(--transition);
}
.mode-card:hover { border-color:var(--accent); }
.mode-card.selected {
  border-color:var(--accent);
  background:rgba(59,130,246,0.08);
}
.mode-icon { font-size:28px; flex-shrink:0; }
.mode-card h3 { font-size:16px; font-weight:600; }
.mode-card p { font-size:13px; color:var(--text-muted); margin-top:2px; }
.mode-count { font-size:12px; color:var(--accent); margin-left:auto; flex-shrink:0; }
.setup-options { margin-bottom:20px; }
.toggle-option {
  display:flex;
  align-items:center;
  gap:10px;
  cursor:pointer;
  font-size:15px;
}
.toggle-option input[type="checkbox"] {
  width:20px; height:20px;
  border-radius:4px;
  accent-color:var(--accent);
  cursor:pointer;
}

/* ============================
   Progress Bar
   ============================ */
.learn-progress {
  display:flex;
  align-items:center;
  gap:12px;
  margin-bottom:20px;
  padding:0 4px;
}
.progress-bar {
  flex:1;
  height:6px;
  background:var(--bg-card2);
  border-radius:3px;
  overflow:hidden;
}
.progress-fill {
  height:100%;
  background:var(--accent);
  border-radius:3px;
  transition:width 0.4s ease;
}
.learn-progress span { font-size:13px; color:var(--text-muted); flex-shrink:0; }

/* ============================
   Flashcards
   ============================ */
.flashcard-wrapper {
  position:relative;
  margin-bottom:24px;
}
.flashcard {
  perspective:1200px;
  height:300px;
  cursor:pointer;
  -webkit-tap-highlight-color:transparent;
}
.flashcard-inner {
  position:relative;
  width:100%; height:100%;
  transition:transform 0.55s cubic-bezier(0.4,0.2,0.2,1);
  transform-style:preserve-3d;
}
.flashcard-inner.flipped { transform:rotateY(180deg); }
.flashcard-front,
.flashcard-back {
  position:absolute;
  inset:0;
  backface-visibility:hidden;
  -webkit-backface-visibility:hidden;
  border-radius:var(--radius);
  display:flex;
  flex-direction:column;
  padding:24px 20px;
  border:1px solid var(--border);
}
.flashcard-front { background:var(--bg-card); }
.flashcard-back  { background:#1a3450; border-color:#2d5180; transform:rotateY(180deg); }
.card-label {
  font-size:11px;
  font-weight:600;
  letter-spacing:1px;
  text-transform:uppercase;
  color:var(--text-dim);
  margin-bottom:12px;
}
.card-text {
  flex:1;
  font-size:18px;
  font-weight:500;
  line-height:1.5;
  overflow-y:auto;
  display:flex;
  align-items:center;
}
.card-hint {
  font-size:12px;
  color:var(--text-dim);
  text-align:center;
  margin-top:12px;
}
.flashcard-back .card-text { font-size:15px; font-weight:400; color:#cbd5e1; align-items:flex-start; }

.flashcard-actions {
  display:flex;
  gap:12px;
  margin-bottom:16px;
}
.btn-wrong, .btn-correct {
  flex:1;
  padding:14px;
  border-radius:var(--radius-sm);
  font-size:16px;
  font-weight:600;
  transition:background var(--transition), transform 0.1s;
}
.btn-wrong {
  background:rgba(239,68,68,0.15);
  color:#fca5a5;
  border:1px solid rgba(239,68,68,0.3);
}
.btn-wrong:hover { background:rgba(239,68,68,0.25); }
.btn-correct {
  background:rgba(34,197,94,0.15);
  color:#86efac;
  border:1px solid rgba(34,197,94,0.3);
}
.btn-correct:hover { background:rgba(34,197,94,0.25); }
.btn-wrong:active, .btn-correct:active { transform:scale(0.96); }

.session-score {
  display:flex;
  justify-content:center;
  gap:20px;
  font-size:15px;
  font-weight:600;
}
.score-correct { color:var(--success); }
.score-wrong   { color:var(--danger); }

.btn-star-wrapper {
  position:absolute;
  top:8px; right:8px;
  z-index:5;
}

/* ============================
   Quiz
   ============================ */
.quiz-container {
  display:flex;
  flex-direction:column;
  gap:16px;
  position:relative;
}
.quiz-container > .btn-star {
  position:absolute;
  top:-8px; right:-8px;
}
.quiz-question {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:20px;
  font-size:16px;
  font-weight:500;
  line-height:1.5;
  min-height:80px;
}
.quiz-options {
  display:flex;
  flex-direction:column;
  gap:10px;
}
.quiz-option {
  background:var(--bg-card);
  border:2px solid var(--border);
  border-radius:var(--radius-sm);
  padding:14px 16px;
  text-align:left;
  font-size:15px;
  color:var(--text);
  transition:border-color var(--transition), background var(--transition);
  line-height:1.4;
}
.quiz-option:hover:not(:disabled) { border-color:var(--accent); background:rgba(59,130,246,0.06); }
.quiz-option.correct {
  border-color:var(--success);
  background:rgba(34,197,94,0.1);
  color:#86efac;
}
.quiz-option.wrong {
  border-color:var(--danger);
  background:rgba(239,68,68,0.1);
  color:#fca5a5;
}
.quiz-option:disabled { cursor:default; }
.explanation {
  background:rgba(59,130,246,0.08);
  border:1px solid rgba(59,130,246,0.2);
  border-radius:var(--radius-sm);
  padding:14px 16px;
  font-size:14px;
  color:#93c5fd;
  line-height:1.5;
}

/* ============================
   Chat Mode
   ============================ */
.chat-container { display:flex; flex-direction:column; gap:16px; position:relative; }
.chat-container > .btn-star { position:absolute; top:-8px; right:-8px; }
.chat-question {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:20px;
  font-size:16px;
  font-weight:500;
  line-height:1.5;
}
.feedback-panel {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:18px;
  display:flex;
  flex-direction:column;
  gap:14px;
}
.feedback-header {
  display:flex;
  align-items:center;
  gap:12px;
}
.feedback-badge {
  padding:4px 12px;
  border-radius:20px;
  font-size:13px;
  font-weight:600;
}
.badge-sehr-gut  { background:rgba(34,197,94,0.2);  color:#86efac; }
.badge-gut       { background:rgba(59,130,246,0.2); color:#93c5fd; }
.badge-ausreichend { background:rgba(245,158,11,0.2); color:#fcd34d; }
.badge-ungenuegend { background:rgba(239,68,68,0.2);  color:#fca5a5; }
.feedback-points { font-size:15px; font-weight:700; color:var(--text-muted); }
.feedback-section h4 {
  font-size:13px;
  font-weight:600;
  text-transform:uppercase;
  letter-spacing:0.5px;
  margin-bottom:8px;
  color:var(--text-muted);
}
.feedback-section ul { display:flex; flex-direction:column; gap:6px; }
.feedback-section li { font-size:14px; line-height:1.4; padding-left:12px; position:relative; }
.feedback-section li::before {
  content:'•';
  position:absolute;
  left:0;
  color:var(--text-dim);
}
details.musterantwort {
  background:var(--bg-input);
  border-radius:var(--radius-sm);
  padding:12px 14px;
}
details.musterantwort summary {
  cursor:pointer;
  font-size:14px;
  color:var(--accent);
  font-weight:500;
  list-style:none;
}
details.musterantwort summary::-webkit-details-marker { display:none; }
details.musterantwort > div {
  font-size:14px;
  color:var(--text-muted);
  line-height:1.6;
  margin-top:10px;
  white-space:pre-wrap;
}

/* ============================
   Editor
   ============================ */
.editor-tabs {
  display:flex;
  border-bottom:1px solid var(--border);
  margin:0 -16px;
  padding:0 16px;
  gap:0;
  position:sticky;
  top:0;
  background:var(--bg);
  z-index:10;
}
#editor-list { padding-top:12px; display:flex; flex-direction:column; gap:8px; padding-bottom:80px; }
.editor-item {
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  padding:12px 14px;
  display:flex;
  gap:10px;
  align-items:flex-start;
}
.editor-item-content { flex:1; min-width:0; }
.editor-item-q { font-size:14px; font-weight:500; margin-bottom:4px; }
.editor-item-a { font-size:13px; color:var(--text-muted); line-height:1.4; }
.editor-item-actions { display:flex; align-items:center; gap:4px; flex-shrink:0; }
.btn-edit, .btn-delete {
  width:32px; height:32px;
  border-radius:var(--radius-sm);
  display:flex; align-items:center; justify-content:center;
  font-size:16px;
  color:var(--text-dim);
  transition:color var(--transition), background var(--transition);
}
.btn-edit:hover  { color:var(--accent); background:rgba(59,130,246,0.1); }
.btn-delete:hover { color:var(--danger); background:rgba(239,68,68,0.1); }
.btn-fab-bottom {
  position:fixed;
  bottom:24px; right:20px;
  padding:12px 20px;
  border-radius:24px;
  box-shadow:var(--shadow);
  z-index:50;
}

/* ============================
   Modals
   ============================ */
.modal-overlay {
  position:fixed;
  inset:0;
  background:rgba(0,0,0,0.6);
  z-index:200;
  backdrop-filter:blur(4px);
  opacity:0;
  transition:opacity 0.2s;
}
.modal-overlay.visible { opacity:1; }
.modal {
  position:fixed;
  left:50%; bottom:0;
  transform:translateX(-50%) translateY(100%);
  width:100%;
  max-width:500px;
  background:var(--bg-card);
  border-radius:var(--radius) var(--radius) 0 0;
  z-index:210;
  transition:transform 0.3s cubic-bezier(0.4,0,0.2,1);
  max-height:90vh;
  overflow-y:auto;
}
.modal.open { transform:translateX(-50%) translateY(0); }
.modal-header {
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:18px 20px 14px;
  border-bottom:1px solid var(--border);
}
.modal-header h3 { font-size:17px; font-weight:600; }
.modal-body {
  padding:20px;
  display:flex;
  flex-direction:column;
  gap:16px;
}
.modal-body p { font-size:14px; color:var(--text-muted); line-height:1.5; }
.modal-footer {
  display:flex;
  gap:10px;
  padding:16px 20px;
  border-top:1px solid var(--border);
}
.modal-footer .btn { flex:1; }

/* ============================
   Session Complete
   ============================ */
.session-results {
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:8px;
  padding:8px 0;
}
.result-big {
  font-size:48px;
  font-weight:700;
  color:var(--accent);
}
.result-sub { font-size:15px; color:var(--text-muted); }
.result-row {
  display:flex;
  gap:20px;
  margin-top:8px;
}
.result-item { display:flex; flex-direction:column; align-items:center; gap:2px; }
.result-item-num { font-size:22px; font-weight:700; }
.result-item-lbl { font-size:12px; color:var(--text-muted); }

/* ============================
   Loading & Toast
   ============================ */
#loading-overlay {
  position:fixed;
  inset:0;
  background:rgba(15,23,42,0.85);
  z-index:500;
  display:flex;
  align-items:center;
  justify-content:center;
  flex-direction:column;
  gap:16px;
  backdrop-filter:blur(8px);
}
.spinner-large {
  width:48px; height:48px;
  border:3px solid var(--border);
  border-top-color:var(--accent);
  border-radius:50%;
  animation:spin 0.8s linear infinite;
}
#loading-text { font-size:15px; color:var(--text-muted); }
@keyframes spin { to { transform:rotate(360deg); } }

#toast-container {
  position:fixed;
  bottom:80px; left:50%;
  transform:translateX(-50%);
  z-index:300;
  display:flex;
  flex-direction:column;
  gap:8px;
  pointer-events:none;
  width:calc(100% - 32px);
  max-width:400px;
}
.toast {
  padding:12px 16px;
  border-radius:var(--radius-sm);
  font-size:14px;
  text-align:center;
  animation:toastIn 0.3s ease, toastOut 0.3s ease 2.7s forwards;
  pointer-events:auto;
}
.toast-success { background:#166534; color:#bbf7d0; border:1px solid #15803d; }
.toast-error   { background:#7f1d1d; color:#fecaca; border:1px solid #b91c1c; }
.toast-info    { background:#1e3a5f; color:#bfdbfe; border:1px solid #1d4ed8; }
@keyframes toastIn  { from { opacity:0; transform:translateY(8px); } to { opacity:1; transform:translateY(0); } }
@keyframes toastOut { from { opacity:1; } to { opacity:0; } }

/* ============================
   Utilities
   ============================ */
.hidden { display:none !important; }
.divider { height:1px; background:var(--border); margin:8px 0; }
.text-muted { color:var(--text-muted); }
.text-center { text-align:center; }
.mt-8  { margin-top:8px; }
.mt-16 { margin-top:16px; }
.gap-8  { gap:8px; }
.flex-row { display:flex; align-items:center; gap:10px; }
.flex-between { display:flex; align-items:center; justify-content:space-between; }

/* ============================
   Responsive
   ============================ */
@media (min-width:600px) {
  .flashcard { height:340px; }
  .card-text  { font-size:20px; }
  .modules-grid { grid-template-columns:repeat(auto-fill, minmax(180px,1fr)); }
}
@media (min-width:768px) {
  #view-flashcards,
  #view-quiz,
  #view-chat,
  #view-learn-setup {
    max-width:600px;
    margin:0 auto;
  }
  .modal { border-radius:var(--radius); top:50%; bottom:auto; transform:translateX(-50%) translateY(calc(-50% + 100px)); }
  .modal.open { transform:translateX(-50%) translateY(-50%); }
}