<div id="mine">
      <div class="level">
        <button type="button">初级</button>
        <button type="button">中级</button>
        <button type="button">高级</button>
        <button type="button">重新开始</button>
      </div>
      <div class="gameBox"></div>
      <div class="info">
        剩余雷数：<span class="mineNum"></span>
      </div>
    </div>

#mine {
  margin: 50px auto;
}
.level {
  text-align: center;
  margin-bottom: 10px;
}
.level button {
  padding: 5px 15px;
  background-color: cornflowerblue;
  border: none;
  color: #fff;
  border-radius: 3px;
  outline: none;
  cursor: pointer;
}
.level button.active {
  background-color: #00abff;
}
.info {
  margin-top: 10px;
  text-align: center;
}
table {
  border-spacing: 1px;
  background: #929196;
  margin: 0 auto;
}
td {
  padding: 0;
  width: 20px;
  height: 20px;
  background: #ccc;
  border: 2px solid;
  border-color: #fff #a1a1a1 #a1a1a1 #fff;
  
  text-align: center;
  line-height: 20px;
  font-weight: bold;
}
td.zero {
  border-color: #D9D9D9;
  background: #D9D9D9;
}
td.one {
  border-color: #D9D9D9;
  background: #D9D9D9;
  color: #0332fe;
}
td.two {
  border-color: #D9D9D9;
  background: #D9D9D9;
  color: #019f02;
}
td.three {
  border-color: #D9D9D9;
  background: #D9D9D9;
  color: #ff2600;
}
td.four {
  border-color: #D9D9D9;
  background: #D9D9D9;
  color: #93208f;
}
td.five {
  border-color: #D9D9D9;
  background: #D9D9D9;
  color: #019f02;
}
td.six {
  border-color: #D9D9D9;
  background: #D9D9D9;
  color: #ff3fff;
}
td.seven {
  border-color: #D9D9D9;
  background: #D9D9D9;
  color: #3fffbf;
}
td.eight {
  border-color: #D9D9D9;
  background: #D9D9D9;
  color: #22ee0f;
}
.mine {
  background: #d9d9d9 url(./mine.png) no-repeat center;
  background-size: cover;
}
.flag {
  background: #ccc url(./flag.png) no-repeat center;
  background-size: cover;
}