:root {
  --bg: #0b1220;
  --card: #121a2b;
  --text: #e8eefc;
  --muted: #9bb0d3;
  --accent: #4cc9f0;
  --border: #1f2937;
  --hover: #34d399;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Inter, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  height: 100%;
  margin: 0;
}

h1, h2, h3 {
  margin-bottom: 8px;
}

p {
  color: var(--muted);
}

.app {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px;
}

footer {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px;
}

.card {
  background: var(--card);
  padding: 16px;
  border-radius: 14px;
  border: 1px solid var(--border);
  box-shadow: 0 6px 20px rgba(0,0,0,.2);
  margin-bottom: 14px;
}

section {
  padding-top: 1rem;
}

.stem {
  font-size: 1.1rem;
  margin-bottom: 10px;
}

.choices {
  display: grid;
  gap: 10px;
  margin-top: 8px;
}

.choice {
  text-align: left;
  background: transparent;
  border: 1px solid #2a3655;
  color: var(--text);
  padding: 10px 12px;
  border-radius: 10px;
  cursor: pointer;
}

.choice:hover {
  border-color: var(--accent);
}

.feedback {
  margin-top: 12px;
  background: #0e2333;
  border: 1px solid #1e3755;
  padding: 12px;
  border-radius: 10px;
}

.panel {
  display: grid;
  gap: 14px;
}

.progress {
  background: #0e1526;
  border: 1px solid #1a2a4a;
  border-radius: 12px;
  padding: 12px;
  margin:8px 0 16px;
}

.controls {
  display: flex;
  gap: 8px;
}

button, .btn {
  background: #183459;
  color: #fff;
  border: 1px solid #2b4b7a;
  padding: 7px 12px;
  border-radius: 10px;
  cursor: pointer;
  margin: 1rem 0;
}

button:disabled {
  opacity: 0.6;
  cursor: default;
}

.btn {
  text-decoration: none;
  margin: 0.5rem 0;
}

.row {
  display: flex;
  gap: 16px;
}

.chapter-list {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  list-style: none;
  padding: 0;
}

.chapter-list li {
  border-radius: 12px;
  padding: 16px;
  background: var(--card);
  border: 1px solid var(--border);
}

.chapter-list li h3 {
  margin-bottom: 6px;
}

.chapter-list li p {
  color: var(--muted);
  margin-bottom: 10px;
}

.chapter-list li a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}


.lesson-list {
  display: grid;
  gap: 12px;
  list-style: none;
  padding: 0;
}

.lesson-list li {
  padding: 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--card);
}

.lesson-list li a {
  color: var(--accent);
  font-weight: 500;
  text-decoration: none;
}


.flashcard article {
  background: var(--card);
  padding: 16px;
  border-radius: 12px;
  border: 1px solid var(--border);
  margin-bottom: 14px;
}

.flashcard details summary {
  color: var(--hover);
  font-weight: 600;
  cursor: pointer;
}

.flashcard details p {
  margin-top: 6px;
  color: var(--muted);
}
.toast { padding:12px 0px; border-radius:10px; margin-bottom:12px; }

.action-buttons {
  display: flex;
  gap: 10px;
  justify-content: space-between;
}

/* .toast.warn { background:#7c2d12; color:#fff; }
.toast.info { background:#1e293b; color:#cbd5e1; }
.toast.success { background:#065f46; color:#ecfdf5; } */

/* 
.app { max-width: 900px; margin: 32px auto; padding: 0 16px; }
.card { background:#151a22; border:1px solid #2a3342; border-radius:12px; padding:16px; margin:16px 0; }
.quiz-card .choices { display:flex; flex-direction:column; gap:10px; margin:12px 0; }
.choice { display:flex; gap:8px; align-items:flex-start; }
.row { display:flex; gap:12px; }
.btn { padding:10px 14px; border-radius:10px; border:1px solid #2a3342; text-decoration:none; display:inline-block; }
.btn.primary { background:#3b82f6; color:#fff; border-color:#3b82f6; }
.btn.secondary { background:transparent; color:#cbd5e1; }
.toast { padding:12px 14px; border-radius:10px; margin-bottom:12px; }
.toast.warn { background:#7c2d12; color:#fff; }
.toast.info { background:#1e293b; color:#cbd5e1; }
.toast.success { background:#065f46; color:#ecfdf5; }
.progress { display:flex; justify-content:space-between; align-items:center; margin:8px 0 16px; }
.muted { color:#94a3b8; } */