validation - css 不会验证不断收到解析错误@media handheld，只有屏幕和(最大宽度 : 320px) error

Question

无法弄清楚我的所有其他移动设备媒体查询有什么问题只验证我的最后一个不会我似乎无法在任何地方找到答案。我已经坚持了一段时间。不确定如何修复它，这是我第一次使用媒体查询，我使用 1140 网格和 html5 不知道如何让它进行验证。

body {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    background:url(../images/background.jpg);
    margin-left:auto;
    margin-right:auto;
    }

    p {
        font-family:Arial, Helvetica, sans-serif;
        font-size:18px;
    }


    h2 {

        font-family:Arial, Helvetica, sans-serif;
        font-size:24px;
        font-weight:bold;
        color:#000;
    }

    h4 {
        font-size:18px;
    }

    h3 {
        font-size:16px;
    }

    .hidden {
        display: none;
    }


        header nav {
        float:right;
        width:670px;
        height:70px;
        margin-top: 47px;
        font-family: Arial, Helvetica, sans-serif;
        background-image: url(../images/nav_bar.png);
        background-repeat:no-repeat;
    }

    nav ul li {
        float: left;
        cursor: pointer;
        list-style-type: none;
        padding-top:20px;
        padding-left:40px;
        text-align: left;
    }

    nav ul {

        font:Arial, Helvetica, sans-serif;
        font-size:24px;
        color:#FFF;
    }

nav ul li a {
    color: #FFF;
    text-decoration: none;
    }

    .logo {
        margin-top:87px;
    }

    .lineone {
        background:#000;
        height:5px;
        width:891px;
        float:right;
        margin-top:30px;
    }

    /*----Home----*/

    .photos {
        width:1140px;
        margin-left:55px;;
        margin-top:40px;
    }

    .about {
        margin-top:50px;
        margin-left:35px;
    }

    .linetwo {
        background:#000;
        height:5px;
        width:1102px;
        margin-left:35px;
        margin-top:10px;
    }


    .contenthome {
        margin-left:56px;
        margin-top:20px;
    }


/*----info-----*/

.lineinfo{
        background:#000;
        height:3px;
        width:625px;
}

#mainContent {
    margin-top:45px;    
}

#mainContent h2 {
    margin-top:50px;

}

#mainContent p {
    font-family:Arial, Helvetica, sans-serif;
    font-weight:lighter;
    font-size:18px; 
}

#mainImage{
    margin-top:40px;
    margin-left:20px;

}

.footer {
    background-image:url(../images/footer.png);
    background-repeat:no-repeat;
    float:left;
    padding-bottom:200px;
    height:100px;
    width:1129px;
    margin-top:182px;
}
.footer h3 {
    margin-left: auto;
    margin-right:auto;
    text-align:center;
    padding-top:43px;
}







/* ============================= */
/* ! Layout for mobile version   */
/* ============================= */


@media handheld, only screen and (max-width: 990px) {
    .lineinfo {
        width:90%;
    }
}

@media handheld, only screen and (max-width: 900px) {
    .logo{
        margin-top:130px;

    }

    .lineinfo {
        width:90%;
    }

}



@media handheld, only screen and (max-width: 767px) {

    .logo {
        margin-top:20px;
        width:90%;
        height:90%;
        margin-left:auto;
        margin-right:auto;
    }



    header nav {
        float:none;
        margin: 20px;
        margin-right:auto;
        margin-left:auto;
        margin-bottom:0px;
        width:300px;


}

    header nav ul li {
        margin:auto;
        height:10px;
        padding-right:20px;
        font-size:16px; 
        }


    .photos {
        width:75%;

}

#mainImage {
margin-right:auto;
margin-left:auto;

}
.lineinfo {
        width:90%;
    }

.footer {
    width:90%;

    background-image:url(../images/footer_media.png);

}
.footer h3{
    font-size:.875em;
}

@media handheld, only screen and (max-width: 320px) {


    .logo {
        margin-top:20px;
        margin-left:auto;
        margin-right:auto;
        width:90%;
        }

    header nav {
        float:none;
        margin: 20px;
        margin-right:auto;
        margin-left:auto;
        margin-bottom:0px;
    }


    header nav ul li {
        width:20px;
        font-size:12px;
    }

        .lineinfo {
        width:90%;
    }

    #mainImage {
margin-right:auto;
margin-left:auto;   
}

.footer h3 {
    font-size:.875em;
}
}

Answer 1

您错过了该部分后的结束括号 }:

 @media handheld, only screen and (max-width: 767px) {

只需注意括号:

   .footer h3{ 
       font-size:.875em;
    }
 } /* here. */

    @media handheld, only screen and (max-width: 320px) {