body {
    margin: 0;
}
#page {
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 2000px;
    background-color: aliceblue;
}
#top_bar {
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 70px;
    background-color: #369;
    color: #fff;
}
#game {
    position: absolute;
    left: 0px;
    top: 70px;
    width: 100%;
    height: 620px;
    background-color: #fff;
    clip:auto;
    overflow: hidden;
}
#board {
    position: absolute;
    left: 120px;
    top: 0;
    width: 82vw;
    height: 620px;
}
#footer_bar {
    position: absolute;
    left: 0;
    top: 690px;
    width: 100%;
    height: 48px;
    background-color: #369;
}
.dialog {
    postion: absolute;
    left: 300px;
    top: 110px;
    height: 460px;
    width: 320px;
    background-color: #369;
    border-radius: 30px;
    border: 2px solid #99f;
    padding: 20px 50px;
    color: #fff;
    text-align: center;
    display: none;
}
.dialog h2 {
    font-size: 28px;
    color: #fff;
    margin: 20px 0 20px;
}
.but_start_game {
    position: absolute;
    left: 42vw;
    top: 360px;
    height: 60px;
    width:200px;
    background-color: #f00;
    cursor: pointer;
    border-radius: 15px;
    border: 2px solid #f66;
    font-size: 28px;
    line-height: 60px;
    font-weight: bold;
    text-shadow: 0px 1px 1px #f99;    
}
.but_start_game:hover {
    background-color: #f33;
}
#start_game {
    display:block;
}