html {
  overflow: auto;
}

.topDiv {
    margin: 0 auto; /*中央寄せ*/
    width: 80%;
}
p.explanation {
    font-size: 12px;
    font-weight: 700;
}


.square_btn {
    display: block;
    position: relative;
    width: 160px;
    padding: 0.8em;
    text-align: center;
    text-decoration: none;
    color: #1B1B1B;
    background: #fff;
    border: 1px solid #1B1B1B;
    margin: 0 auto;
}

    .square_btn:hover {
        background: #1B1B1B;
        color: #fff;
        cursor: pointer;
        text-decoration: none;
    }

.square_btn_kaiin {
    display: block;
    position: relative;
    width: 100px;
    padding: 0.8em;
    text-align: center;
    text-decoration: none;
    color: #1B1B1B;
    background: #fff;
    border: 1px solid #1B1B1B;
    margin-right: auto;
}

    .square_btn_kaiin:hover {
        background: #1B1B1B;
        color: #fff;
        cursor: pointer;
        text-decoration: none;
    }

input.tdForm {
    width: 100%;
    height: 100%;
    padding: 5px 8px;
    border-radius: 6px;
    border-top: 1px solid #aaa;
    border-left: 1px solid #aaa;
    border-right: 2px solid #aaa;
    border-bottom: 2px solid #aaa;
    background-image: none;
    background-color: #FFF;
    font-size: 16px;
    box-sizing: border-box; /* ※これがないと横にはみ出る */
}

textarea.tdForm {
    height: 120px;
    width: 100%;
    padding: 5px 8px;
    border-radius: 6px;
    border-top: 1px solid #aaa;
    border-left: 1px solid #aaa;
    border-right: 2px solid #aaa;
    border-bottom: 2px solid #aaa;
    background-image: none;
    background-color: #ddd;
    font-size: 16px;
    box-sizing: border-box; /* ※これがないと横にはみ出る */
}

table.formTable {
    background-color: #FFFFFF; /*背景色*/
    margin: 0 auto;
    margin-top: 0px; /*上部余白*/
    width: 100%;
    height: 100%;
}

    table.formTable td.tdForm {
        width: 50%;
    }

    table.formTable td.tdFormSelect {
        width: 50%;
        height: 10%
    }

img.hissu {
    margin: 0 auto; /*中央寄せ*/
    max-width: 4%;
    height: auto;
}


@media (max-width: 768px) {

    body {
        width: 100%;
        height: 100%;
        margin: 0 auto;
    }

    img.hissu {
        margin: 0 auto; /*中央せ*/
        min-width: 10%;
        height: auto;
    }
}