#id_MainVisual{
    background-image: url("mainVisual.jpg");
    background-size: cover;
    position: absolute;
    width:100%;
    height:100%;
    top: 0;
    left: 0;
}
#id_MainVisual::before{
    content: "";
    background-color:rgba(255,255,240,0.7);
    position: absolute;
    width:100%;
    height:100%;
    top: 0;
    left: 0;
}
#id_SoftwareName{
    width: 100%;
    height: 30px;
    position: absolute;
    top: 30%;
    text-align: center;
}
/* 画面幅が800px以下のときに適用 */ 
@media (max-width: 800px) { 
    #id_SoftwareName
    { 
        height: 80px;
        top: 5%;
        text-align: center;
    } 
}
#id_SoftwareName h1{
  font-family: "Kosugi Maru", sans-serif;
  font-weight: 400;
  font-style: normal;
  font-size: 70px;
  color: brown;
}
/* 画面幅が800px以下のときに適用 */ 
@media (max-width: 800px) { 
  font-size: 50px;
}
#id_Buttons{
    width: 100%;
    height: 30px;
    position: absolute;
    top: 60%;
    text-align: center;
}
#id_Buttons button{
    margin: 5px 0px 5px 0px;
    width: 170px;
}