body {
  font-family: 'Tahoma', sans-serif;
  margin: 0;
  background: #f8f8f8;
  color: #333;
}
.app-header {
  background: #6200ea;
  color: white;
  padding: 1rem;
  text-align: center;
}
.subjects {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding: 1rem;
}
.fab {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: #6200ea;
  color: white;
  border: none;
  border-radius: 50%;
  width: 56px;
  height: 56px;
  font-size: 24px;
  cursor: pointer;
}
.hidden { display: none; }
.tabs {
  display: flex;
  justify-content: space-around;
  background: #eee;
  padding: 0.5rem;
}
.tabs button {
  flex: 1;
  padding: 0.5rem;
  border: none;
  background: transparent;
  cursor: pointer;
}