* {
    font-family: 'Courier New', Courier, monospace;
}

h1 {
    font-size: 26px;
    /* font-weight: lighter; */
    color: blue;
}

h3 {
    font-size: 18px;
    font-weight: lighter;
    color: black;
}

.div1 {
    font-size: 18px;
    /* width: 680px; */
    padding: 20px;
    border-width: 0px;
    border-color: #ff00aa;
    border-style: solid;
    width: 680px;
    margin: 5% auto;


    /* 鼠标点击文字不松开的效果 */
    :active {
        color: #00CC00;
    }

    /* 鼠标选中文字的效果 */
    ::selection {
        color: #fff;
        background: #00CC00;
    }
}

span {
    font-size: 18px;
    color: blue;
}



/* 媒体查询，移动客户端适配。 */
/* 
@media screen and (max-width:768px) {

    body {
        width: 400px;
    }

}

@media screen and (max-width:768px) {

    body {
        width: 680px;
    }

}  */