body, h1, h2, h3 {
  margin: 0;
  padding: 0;
  font-family: 'Open Sans', sans-serif;
}

/* 弹出框样式 */
.modal {
  display: none;
  position: fixed;
  z-index: 1000;
  left: 0;
  top: 20%;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgba(0, 0, 0, 0.7);
}

/* 弹出框内容区域样式 */
.modal-content {
  background-color: #fefefe;
  margin: 5% auto;
  padding: 20px;
  border: none;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
  width: 80%;
  max-width: 700px;
  border-radius: 8px;
  animation-name: modalOpen;
  animation-duration: 0.4s;
  text-align: center;
}

/* 关闭按钮样式 */
.close {
  color: #fff;
  background-color: #e74c3c;
  float: right;
  font-size: 28px;
  font-weight: bold;
  cursor: pointer;
  border-radius: 50%;
  width: 30px;
  height: 30px;
  line-height: 30px;
  text-align: center;
  margin: -10px -10px 10px 10px;
}

.close:hover,
.close:focus {
  color: #fff;
  background-color: #c0392b;
  text-decoration: none;
}

/* 弹出框标题样式 */
.modal-header {
  border-bottom: 1px solid #eaeaea;
  padding-bottom: 10px;
}

/* 弹出框正文样式 */
.modal-body {
  margin-top: 20px;
  line-height: 1.8;
  color: #333;
}

/* 弹出框按钮样式 */
.modal-footer {
  text-align: center;
  margin-top: 20px;
}

/* 弹出框动画效果 */
@keyframes modalOpen {
  from {opacity: 0;}
  to {opacity: 1;}
}

/* 段落样式 */
.modal-body p {
  margin-bottom: 15px;
  text-align: justify;
}

/* 按钮样式 */
.modal-footer button {
  background-color: #3498db;
  color: #fff;
  border: none;
  padding: 10px 20px;
  font-size: 16px;
  cursor: pointer;
  border-radius: 5px;
  transition: background-color 0.3s ease;
}

.modal-footer button:hover {
  background-color: #2980b9;
}