/* ─── Concept Cards ─── */

.concept-card {
  display: block;
  border-radius: 12px;
  border: 1px solid var(--border-light, #e5e7eb);
  background: var(--card-bg, #ffffff);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  height: 100%;
}

.concept-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.concept-card-icon {
  font-size: 1.5rem;
}

.concept-card-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary, #1e293b);
  margin: 0;
}

.concept-card-description {
  font-size: 0.85rem;
  line-height: 1.4;
}

.concept-pill {
  display: inline-flex;
  align-items: center;
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  border-radius: 6px;
  background: var(--pill-bg, #f1f5f9);
  color: var(--text-secondary, #64748b);
}

.concept-pill i {
  font-size: 0.65rem;
}

/* ─── Concept Page ─── */

.concept-description {
  font-size: 1.05rem;
  line-height: 1.7;
  color: var(--text-primary, #1e293b);
}

.concept-scene-wrapper {
  max-width: 100%;
}

.concept-scene-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary, #1e293b);
  margin-bottom: 0.5rem;
}

.concept-scene-description {
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--text-secondary, #64748b);
}

.concept-scene-container {
  border-radius: 12px;
  border: 1px solid var(--border-light, #e5e7eb);
  background: var(--card-bg, #ffffff);
  overflow: hidden;
  width: 100%;
}

/* JSXGraph board */
.concept-jsxgraph-board {
  width: 100%;
}

.concept-jsxgraph-board svg {
  border-radius: 12px;
}

/* Matter.js canvas */
.concept-matter-canvas {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 12px;
}

/* Controls */
.concept-matter-controls {
  padding: 0.5rem 0;
}

.concept-control-label {
  font-size: 0.85rem;
  font-weight: 500;
  min-width: 80px;
  color: var(--text-primary, #1e293b);
}

.concept-control-value {
  font-size: 0.85rem;
  font-weight: 600;
  min-width: 40px;
  text-align: right;
  color: var(--text-primary, #1e293b);
}

/* ─── Concept Embed (in exercise pages) ─── */

.concept-embed-card {
  border-radius: 12px;
  border: 1px solid var(--border-light, #e5e7eb);
  background: var(--card-bg, #ffffff);
  overflow: hidden;
}

.concept-embed-header {
  padding: 0.75rem 1rem;
  background: var(--pill-bg, #f1f5f9);
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-primary, #1e293b);
}

.concept-embed-header i {
  color: var(--primary, #5bade0);
}

.concept-embed-body {
  padding: 0;
}

.concept-embed-body .concept-scene-container {
  border: none;
  border-radius: 0;
}

.concept-embed-link {
  display: block;
  padding: 0.5rem 1rem;
  text-align: center;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--primary, #5bade0);
  text-decoration: none;
  border-top: 1px solid var(--border-light, #e5e7eb);
}

.concept-embed-link:hover {
  background: var(--pill-bg, #f1f5f9);
}

/* ─── Badge ─── */

.badge.bg-outline {
  background: transparent;
  border: 1px solid var(--border-light, #e5e7eb);
  color: var(--text-secondary, #64748b);
  font-weight: 500;
}

/* ─── Dark Mode ─── */

@media (prefers-color-scheme: dark) {
  .concept-card {
    border-color: #334155;
    background: #1e293b;
  }

  .concept-card:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  }

  .concept-card-title,
  .concept-scene-title,
  .concept-control-label,
  .concept-control-value,
  .concept-description {
    color: #e2e8f0;
  }

  .concept-card-description,
  .concept-scene-description {
    color: #94a3b8;
  }

  .concept-pill {
    background: #334155;
    color: #94a3b8;
  }

  .concept-scene-container {
    border-color: #334155;
    background: #1e293b;
  }

  .concept-embed-card {
    border-color: #334155;
    background: #1e293b;
  }

  .concept-embed-header {
    background: #0f172a;
    color: #e2e8f0;
  }

  .concept-embed-link {
    border-color: #334155;
    color: #60a5fa;
  }

  .concept-embed-link:hover {
    background: #0f172a;
  }

  .badge.bg-outline {
    border-color: #334155;
    color: #94a3b8;
  }
}

/* ─── Responsive ─── */

@media (max-width: 768px) {
  .concept-scene-container {
    max-width: 100% !important;
  }

  .concept-matter-canvas {
    max-width: 100%;
  }
}