/* Orange Theme */
.orange-gradient {
  background: linear-gradient(135deg, #e56d00, #ff8c42);
}

/* Sidebar */
.sidebar {
  position: fixed;
  top: 0;
  left: -270px;
  width: 270px;
  height: 100%;
  background: #fff;
  box-shadow: 2px 0 8px rgba(0, 0, 0, 0.2);
  overflow-y: auto;
  transition: left 0.4s ease;
  z-index: 1050;
}
.sidebar.active {
  left: 0;
}
.sidebar-header {
  background: #e56d00;
  color: #fff;
  padding: 1rem;
}
.sidebar-body {
  padding: 1rem;
}
.sidebar-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.5);
  display: none;
  z-index: 1040;
}
.sidebar-overlay.active {
  display: block;
}
.chapter-item.active {
  background: #fff3e0;
  border-left: 4px solid #e56d00;
}

/* Buttons */
.btn-secondary {
  background-color: #e56d00 !important;
  border: none;
  transition: 0.3s;
}
.btn-secondary:hover {
  background-color: #ff8c42 !important;
}

/* Dark Mode */
body.dark-mode {
  background: #121212;
  color: #f1f1f1;
  transition: background 0.4s, color 0.4s;
}
body.dark-mode .card {
  background: #1e1e1e;
  color: #f1f1f1;
}
body.dark-mode .bg-light {
  background: #222 !important;
}
body.dark-mode .sidebar {
  background: #1f1f1f !important;
}
body.dark-mode .sidebar-header {
  background: #ff8c42 !important;
}