body, html {
    display: flex;
    justify-content: center;
    background-color: #f0f0f0;
}

.table-container,th,td { /* 设置边框为1像素宽的黑色实线 */
    background-color: white;
    border: 1px solid black;
    text-align: center;
    border-collapse: collapse;
    font-size: 20px;
    padding: 15px;
}
.main{
    text-align: center;,
}
button{
    font-size: 30px;
}
.foot{
    font-size: 25px;
    text-align: center;
    width: 100%;
    height: 50px;
    line-height: 50px;
    border-top: 2px solid #61a0ca;
    margin-top: 100px;
}