h1 {
  text-align: center;
  font-size: 70px; /* 放大字体 */
  /* font-family: Arial, sans-serif; */
  color: #333;
  margin-top: 160px; /* 增加下边距来向上移动标题 */
  margin-bottom: 0px; /* 增加下边距来向上移动标题 */
}
h2 {
  text-align: center;
  font-size: 50px; /* 放大字体 */
  /* font-family: Arial, sans-serif; */
  color: #333;
  margin-top: 20px; /* 增加下边距来向上移动标题 */
  margin-bottom: 60px; /* 增加下边距来向上移动标题 */
}

body {
  display: flex;
  flex-direction: column; /* 设置子元素在垂直方向上排列 */
  justify-content: space-around; /* 设置子元素在垂直方向上均匀分布 */
  align-items: center;
    height: 20vh;
  margin: 0;
  background-color: #f0f0f0;
  font-family: Arial, sans-serif;
}

.timer-container {
  background-color: #fff;
  padding: 40px;
  border-radius: 10px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

.timer {
  font-size: 72px;
  font-weight: bold;
  color: #333;
  margin-bottom: 20px;
}

.controls {
  display: flex;
  justify-content: center;
  gap: 20px;
}

.btn {
  background-color: #007bff;
  color: #fff;
  border: none;
  padding: 10px 20px;
  border-radius: 5px;
  font-size: 16px;
  cursor: pointer;
  transition: background-color 0.3s;
}

.btn:hover {
  background-color: #0056b3;
}