/* Cấu trúc chung cho toàn trang */
body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
  padding: 20px;
  line-height: 1.6;
}

.exercise-title {
  margin-bottom: 30px;
}

/* Khối tin nhắn (Màu vàng nhạt) */
.message-card {
  border: 2px solid #5b79ff;
  background-color: #ffffd1;
  padding: 40px 60px;
  border-radius: 15px;
  max-width: 800px;
  margin: 0 auto 50px auto;
  text-align: center;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.title-brown {
  color: #a52a2a;
  text-transform: uppercase;
  font-size: 24px;
  margin-bottom: 25px;
  font-weight: bold;
}

.content-text-justify {
  color: #333;
  font-size: 17px;
  margin: 0;
  text-align: justify;
  text-justify: inter-word;
}

/* Khối bài học (Có ảnh nền) */
.lesson-card {
  border: 6px solid #2e3b8b;
  border-radius: 10px;
  max-width: 500px;
  margin: 0 auto;
  padding: 60px 30px;
  text-align: center;
  position: relative;
  /* Hiệu ứng lớp phủ màu tối để chữ nổi bật hơn */
  background-image:
    linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)),
    url("https://images.unsplash.com/photo-1502086223501-7ea6ecd79368?auto=format&fit=crop&q=80&w=1000");
  background-size: cover;
  background-position: center;
  color: white;
}

.title-yellow {
  color: #ffff00;
  font-size: 22px;
  font-weight: bold;
  margin-bottom: 30px;
  text-transform: uppercase;
}

.content-text-center {
  font-size: 16px;
  line-height: 1.5;
  margin: 0;
  text-align: center;
}