html, body {
    height: 100%;
    margin: 0;
}
body {
    background-color: #eee;
    font-family: "meiryo", "hiragino sans";
}
#main {
    background-color: white;
    width: 600px;
    margin: 0 auto;
    text-align: center;
    min-height: 100vh;
    padding: 0 50px;
    padding-bottom: 20px;
}
#main h1{
    margin: 0 -50px;
    margin-top: 0px;
    background-color: #ffa;
}
#main h2{
    font-size: 25px
}
#ok_button{
    background-color: lightskyblue;
    font-size: 20px;
    border-radius: 5px;
}