body {
  font-family: sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background-color: #f0f0f0;
}

.container {
  background-color: #fff;
  padding: 40px;
  border-radius: 10px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  text-align: center;
}

.word-card {
  font-size: 24px;
  margin-bottom: 20px;
  padding: 20px;
  border: 1px solid #ddd;
  border-radius: 5px;
  cursor: pointer;
}

.word-card b {
  display: block;
  font-size: 36px;
  margin-bottom: 10px;
}

.word-card img {  
  height: auto;
  margin-bottom: 10px;
  border-radius: 5px; /* Điều chỉnh giá trị này để thay đổi độ bo tròn */
}

.btn {
  background-color: #007bff;
  color: #fff;
  padding: 20px 20px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  margin: 0 10px;
}

.btn i {
  margin-right: 5px;
}
/* General table styling */
#historyTable {
  width: 100%;
  border-collapse: collapse;
  margin: 0 auto;
}

#historyTable th, 
#historyTable td {
  border: 1px solid #ddd;
  padding: 8px;
  text-align: center;
}

#historyTable tr:nth-child(even) {
  background-color: #f9f9f9;
}

#historyTable tr:hover {
  background-color: #f1f1f1;
}

/* Styling for new learning sessions */
.newSession {
  border-bottom: 2px solid #333;  /* Thicker, darker border */
 
}

/* Header Styling */
#historyTable th {
  padding-top: 12px;
  padding-bottom: 12px;
  background-color: #4CAF50;
  color: white;
}