/*** for PC Browser ***/
@media (min-width:401px)
{
ul.main_btn
{
    background: #BDD7EE;
    margin: 0 0 10px;
    padding: 30px 20px;
    display: flex;
    flex-wrap: wrap;
    width: 100%;
    box-sizing: border-box;
    list-style: none;
}

ul.main_btn li
{
    display: inline-table;
    width: 25%;
    min-height: 90px;
    border-spacing: 5px;
}

ul.main_btn li a
{
    display: table-cell;
    text-align: center;
    vertical-align: middle;
    font-size: x-large;
    font-weight: bold;
    color: #000000;
    text-decoration: none;
    border: 1px solid #bfbfbf;
    border-radius: 5px;
    overflow: hidden;
    background-color: #FFE699;
    box-shadow: 3px 3px 3px #000000;
}

ul.main_btn li:nth-child(n+5) a
{
    background-color: #DCEBD2;
}

ul.main_btn li a:hover
{
    box-shadow: none;
}
}


/*** for Smart Phone ***/
@media (max-width:400px)
{
ul.main_btn
{
    background: #BDD7EE;
    margin: 0 0 10px;
    padding: 10px;
    display: flex;
    flex-wrap: wrap;
    width: 100%;
    box-sizing: border-box;
    list-style: none;
}

ul.main_btn li
{
    display: inline-table;
    width: 50%;
    min-height: 70px;
    border-spacing: 5px;
}

ul.main_btn li a
{
    display: table-cell;
    text-align: center;
    vertical-align: middle;
    font-size: large;
    font-weight: bold;
    color: #000000;
    text-decoration: none;
    border: 1px solid #000000;
    border-radius: 5px;
    overflow: hidden;
    background-color: #FFE699;
}

ul.main_btn li:nth-child(n+5) a
{
    background-color: #DCEBD2;
}
}