body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
  margin: 0;
  padding: 0;
}

.container {
  max-width: 700px;
  margin: auto;
  padding: 20px;
  background: white;
  border-radius: 10px;
  box-shadow: 0 0 15px rgba(0,0,0,0.1);
}

header {
  text-align: center;
  margin-bottom: 20px;
}

button {
  background-color: #1a73e8;
  color: white;
  padding: 10px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
}

button:hover {
  background-color: #0f5fd4;
}

.students-section, .join-class {
  margin-top: 30px;
}

input {
  width: 100%;
  padding: 10px;
  margin-top: 10px;
  border-radius: 6px;
  border: 1px solid #ccc;
}