body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #f7f7f7;
  color: #222;
}

header {
  background: #ffffff;
  padding: 40px 20px;
  text-align: center;
  border-bottom: 1px solid #ddd;
}

main {
  max-width: 900px;
  margin: 0 auto;
  padding: 30px 20px;
}

.lesson {
  background: white;
  padding: 24px;
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.word-box,
.quiz-box {
  margin-bottom: 24px;
}

button {
  margin: 6px 6px 6px 0;
  padding: 10px 16px;
  border: 1px solid #ccc;
  background: #eee;
  border-radius: 8px;
  cursor: pointer;
}

button:hover {
  background: #ddd;
}

#result {
  margin-top: 12px;
  font-weight: bold;
}