body {
  background: #f4f7fb;
  color: #1f2937;
}
.navbar { min-height: 56px; }
.app-main { margin-top: 84px; min-height: calc(100vh - 170px); }
.avatar-nav {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  object-fit: cover;
  background: #fff;
}
.sidebar-card { top: 88px; }
.lesson-content p, .lesson-content li { font-size: 1.05rem; line-height: 1.7; }
.dashboard-tile {
  display: block;
  padding: 1rem 1.25rem;
  border-radius: 1rem;
  background: #e9f2ff;
  text-decoration: none;
  color: #0d3b8a;
  font-weight: 600;
  height: 100%;
}
.dashboard-tile:hover { background: #d9e9ff; }
.question-box {
  border: 1px solid #dbe4f0;
  border-radius: 1rem;
  padding: 1.25rem;
  margin-bottom: 1rem;
  background: #fbfdff;
}
.page-footer { color: #4b5563; }
.ads-box { border: 1px dashed #93c5fd; }
.adsense-demo {
  border-radius: .75rem;
  padding: 1rem;
  background: linear-gradient(135deg, #fef3c7, #dbeafe);
  color: #334155;
  font-weight: 600;
}
.table-max {
  max-height: 420px;
}
.table-max table {
  margin-bottom: 0;
}
.list-group-item.active {
  background: #0d6efd;
  border-color: #0d6efd;
}