Css 为什么此媒体选择器在更宽的页面上处于活动状态？

我使用以下媒体选择器：

@media only screen and (max-width: 651px) 

出于某种原因，在810像素宽的页面上触发了媒体选择器内部的以下css片段

.bar .link{
    width: 92%;
    margin: 0 auto;
}

媒体选择器中的其他css均未触发。为什么？下面是完整的Css

/* ==========================================================================
   HTML5 Boilerplate styles - h5bp.com (generated via initializr.com)
   ========================================================================== */

html,
button,
input,
select,
textarea {
    font-family: GillSansMTStd-Medium;
    color: #222;
}

body {
    font-size: 1em;
    line-height: 1.4;
}

::-moz-selection {
    background: #b3d4fc;
    text-shadow: none;
}

::selection {
    background: #b3d4fc;
    text-shadow: none;
}

hr {
    display: block;
    height: 1px;
    border: 0;
    border-top: 1px solid #ccc;
    margin: 1em 0;
    padding: 0;
}

img {
    vertical-align: middle;
}

fieldset {
    border: 0;
    margin: 0;
    padding: 0;
}

textarea {
    resize: vertical;
}

.chromeframe {
    margin: 0.2em 0;
    background: #ccc;
    color: #000;
    padding: 0.2em 0;
}

input:invalid, textarea:invalid {
    -moz-box-shadow: none;
    box-shadow: none;
}
/* ==========================================================================
   Author's custom styles
   ========================================================================== */
html, body{
    height: 100%;
}


body{
    max-width: 810px;
    background: #e9e2d9;
    font-family: GillSansMTStd-Medium;
    font-weight: normal;
    font-style: normal;
    text-align: center;
}
h1,h2{
    color: #002244;
    font-family: PerpetuaMT-Bold;
    font-weight: normal;
    font-style: normal;
    font-size: 36px;
    padding: 32px 0 0;
    margin: 0;
    line-height: 1em;
    text-transform: uppercase;
    letter-spacing: 1px;
}
.apply h2,.pitch h2{
    padding-top: 50px;
}
h3{
    text-transform: uppercase;
    color: #002244;
    font-family: PerpetuaMT-Bold;
    font-weight: normal;
    font-style: normal;
    font-size: 18px;
    margin-top: 0;
    line-height: 1em;
    letter-spacing: 1px;
}

p, a{
    color: #002244;
    font-size: 12px;
    letter-spacing: 0;
    line-height: 15px;
    text-transform: uppercase;
}
a{
    cursor: pointer;
    text-decoration: underline;
}

span{
    text-transform: uppercase;
}
label span{
    text-decoration: underline;
    cursor: pointer;
}
button[disabled], html input[disabled] {
    opacity: 0.5;
}
.section.pitch{
    background: #e9e2d9;
    padding-top: 25px;
    z-index: 1;
    position: relative;
}
.section.details h3{
    font-size: 20px;
    position: absolute;
    width: 170px;
    top: 72px;
}

p.details{
    margin-bottom: -12px;
}
p.important{
    font-size: 16px;
    margin-top: -4px;
    margin-bottom: -6px;
}
p.minor{
    text-align: justify;
    text-transform: none;
    line-height: 16px;
    margin-bottom: 0;
}
.vote{
    margin: 0 70px 63px 70px;
    max-width: 670px;
}
.vote .byline{
    max-width: 500px;
    margin: 3px auto 0;
}
.special{
    font-size: 20px;
    color: #e9e2d9;
    background-color: #002244;
    text-align: center;
    text-transform: uppercase;
    padding: 12px 0 6px 0;
    font-family: PerpetuaMT-Bold;
    margin: 35px 0 0 0;
    height: 30px;
}

.special p{
    font-size: 25px;
    color: #e9e2d9;
    text-align: center;
    text-transform: uppercase;
    font-family: PerpetuaMT-Bold;
    display: inline;
}

.bar{
    width: 33%;
    display: inline-block;
    float: left;
    margin: 10px 0 32px 0;
}
.bar:hover {
    background: white;
}
.bar .link{
    padding-bottom: 6px;
}
.bar:hover .link{
    background: white;
}
.bar .link p{
    padding: 0 0 7px 0;
    margin: 10px 0 0 0;
}
.bar .link a{
    text-decoration: none;
    display: block;
    font-size: 18px;
}
.bar .link img{
    margin: 0 auto;
    width: 206px;;
}
.bar .link .after{
    margin: 0 auto;
    width: 206px;
    background-color: #002244;
    text-align: right;
    text-transform: uppercase;
    padding: 0;
}
.bar .link .after a{
    color: #e9e2d9;
    font-size: 9px;
    padding: 4px 6px 4px 0
}
.bar .like{
    width: 93%;
    background-color: #002244;
    margin: 0 auto 8px auto;
    height: 75px;
}
.bar .like p{
    color: #e9e2d9;
    margin: 0;
    font-size: 9px;
    padding: 6px 0 18px 0;
    margin: 0 30px;
    line-height: 1.2em;
}
.bar .like .fb_iframe_widget{
    padding: 8px 0 13px 0;
}
.bar .like p.percentage{
    padding: 13px 0 0 0;
    font-size: 18px;
}
.compact{
    margin-bottom: 24px;
}
.compact a{
    line-height: 1em;
}
.small{
    font-size: 9px;
    clear: both;
    padding-top: 10px;
    line-height: 1.3em;
    text-align: justify;
}
.instruction .count{
    position: absolute;
    top: 0!important;
    margin-left: -26px;
    left: 50%;
}
.count{
    color: transparent;
    margin: 11px auto 5px auto;
    height: 50px;
    width: 52px;
}
.count1{
    background: url("../img/1.png") no-repeat center;
}
.count2{
    background: url("../img/2.png") no-repeat center;
}
.count3{
    background: url("../img/3.png") no-repeat center;
}
.count4{
    background: url("../img/4.png") no-repeat center;
}
.disclaimer{
    padding-bottom: 32px;
    border-top: 1px solid #002244;
}
.disclaimer h2{
    padding: 40px 0 16px;
    font-size: 20px;
}
.disclaimer p{
    font-size: 10px;
}
a.label{
    font-size: 12px;
    color: white;
    text-decoration: none;
    line-height: 10px;
    padding: 8px 12px 7px;
    border-radius: 2px;
    background-color: #002244;
    letter-spacing: 1px;
    text-transform: uppercase;
    display: table;
    margin: 0 auto;
}
/*justify last line hack*/
p.details:after
{content: "";
display: inline-block;
width: 100%;}

.fieldset{
    margin-bottom: 10px;
    opacity: 0.3;
    margin-top: 24px;
}


.fieldset:first-child{
    opacity: 1;
}
.video-container{
    height: 0;
    position: relative;
    padding-bottom: 56.25%;
}

.video-container .videopreview{
    position: absolute;
    top: 0;
    background: url("../img/movieposter.png") no-repeat center #002244;
    width: 100%;
    height: 100%;
    cursor: pointer;
    background-size: contain;;
}
.video-container iframe{
    height: 100%;
    width: 100%;
    position: absolute;
    top: 0;
    left: 0;
}

.section{
    padding: 0 46px 32px;
    opacity: 0;
    float: left;
}
.section.blue{
    background-image: url('../img/whitearrow.png'), url('../img/bluearrow.png');
    background-position:  top center, bottom center;
    background-repeat: no-repeat;
    background-color: #002244;
    color: #e9e2d9;
    padding: 22px 45px 52px;
}
.section.blue h2,.section.blue h3, .section.blue p{
    color: #e9e2d9;
}
.jury {
    padding: 24px 0 15px;
}
.jury div{
    width: 24%;
    display: inline-block;
    opacity: 0;
}
.jury div a{
    color: white;
    background-color: #e9e2d9;
    width: 120px;
    height: 80px;
    border-radius: 60px;
    padding-top: 40px;
    font-size: 14px;
    line-height: 1em;
    display: block;
    margin: 0 auto;
    text-decoration: none;
}
.jury div a span{
    color: #002244;
}
.jury div a span span{
    text-decoration: underline;
}


.show{
    opacity: 1 !important;
    -moz-transition: opacity 1s;
    transition: opacity 1s;
}
.showmany>*{
    opacity: 1 !important;
    -moz-transition: opacity 1s;
    transition: opacity 1s;
}
.showmany>.n2{
    transition-delay: .2s;
}
.showmany>.n3{
    transition-delay: .4s;
}
.showmany>.n4{
    transition-delay: .6s;
}
.mathieu .mathieu,.mathieu .mathieu:hover{
    background-image: url('../img/mathieu.jpg');
    top: 6px;
    box-shadow: 0 0;
}
.mathieu .mathieu span{
    display: none;
}
.hirmane .hirmane, .hirmane .hirmane:hover {
    background-image: url('../img/hirmane.jpg');
    top: 6px;
    box-shadow: 0 0;
}

.hirmane .hirmane span{
    display: none;
}
.daniel .daniel,.daniel .daniel:hover{
    background-image: url('../img/daniel.jpg');
    top: 6px;
    box-shadow: 0 0;
}
.daniel .daniel span{
    display: none;
}
.laura .laura,.laura .laura:hover{
    background-image: url('../img/laura.jpg');
    top: 6px;
    box-shadow: 0 0;
}
.laura .laura span{
    display: none;
}

.jury div a span span{
    display: block;
    font-size: 8px;
    line-height: 1em;
    padding-top: 8px;
    text-decoration: underline;
}
.jury div p{
   min-height: 2em;
   letter-spacing: 0;
   margin: 1em auto;
}
.memeberdetailswrapper{
    height: 0;
    overflow: hidden;
    transition: all .5s;
}
.memeberdetailswrapper.expanded{
    height: 115px;
    transition: all .5s;
}

.memberdetails{
    opacity: 0;
    transition: all .3s;
    height: 100px;
    margin-bottom: -100px;
}

.memberdetails.visible{
    opacity: 1;
    transition: all .3s;
    transition-delay: .3s;
}

.instruction {
    width: 170px;
    height: 210px;
    display: inline-table;
    margin: 9px 27px 0;
    opacity: 0;
    position: relative;
}
.instruction p{
    position: absolute;
    top: 100px;
    margin-top: 0;
}
.documentholder{
    color: white;
    margin: 20px 30px;
    display: inline-block;
}

.documentholder div{
    background-size: 41px 51px;
    width: 100px;
    height: 100px;
    border-radius: 50%;
}
.documentholder .document{
    background: url('../img/document.png') center no-repeat #002244;
    background-size: 41px 51px;
}
.documentholder .photo{
    background: url('../img/photo.png') center no-repeat #002244;
    background-size: 60px auto;
}
.documentholder .video{
    background: url('../img/video.png') center no-repeat #002244;
    background-size: 60px auto;
}
.documentholder p {
    margin-top: 10px;
    margin-bottom: 0;
}

.documentholder p.opt {
    font-size: 9px;
    margin-top: 0;
    padding: 0;
}


.fieldset.mybutton{
    opacity: 1;
}

.mybutton{
    clear: both;
}
/* General button style (reset) */
input.mybtn, a.mybtn {
    max-width: 100%;
    white-space: inherit;
    text-decoration: none;
    font-size: 20px;
    margin: 10px auto 27px auto;
    width: auto;
    border: none;
    cursor: pointer;
    padding: 16px 27px 12px;
    display: inline-block;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 700;
    outline: none;
    background: white;
    color: #002244;
    line-height: 1em;
    border-radius: 20px;
}

.documentholder div,.back,.jury div a,.label,input.mybtn, a.mybtn {
    box-shadow: 0 6px;
    position: relative;
}

.documentholder div:after,.back:after,.jury div a:after,.label:after,.mybtn:after {
    content: '';
    position: absolute;
    z-index: -1;
    -webkit-transition: all 0.3s;
    -moz-transition: all 0.3s;
    transition: all 0.3s;
}
.documentholder div:hover,.back:hover,.jury div a:hover,.label:hover,.mybtn:hover{
    box-shadow: 0 4px;
    top: 2px;
}
.documentholder div:active,.back:active,.jury div a:active,.label:active,.mybtn:active {
    box-shadow: 0 0;
    top: 6px;
}
.instructions h2{
    padding: 19px 0 5px;
    font-size: 20px;
}
.footer{
    background: url('../img/footerlogo.png') top center no-repeat #002244;
    height: 220px;
    width: 100%;
    position: relative;
    float: left;
}
.footer p{
    color: #e9e2d9;;
    position: absolute;
    bottom: 18px;
    right: 5px;
    font-size: 10px;
    text-transform: uppercase;
}
#legal{
    position: fixed;
    width: 810px;
    background: white;
    padding-bottom: 100px;
    z-index: 5;
}
#legal p{
    padding: 6px 0 4px;
    font-size: 14px;
    margin: 0;
    letter-spacing: 3px;
}
.mybtn.computerbtn{
    display: none;
}
.backwrapper{
    position: absolute;
    left: 17px;
}
.backwrapperlast{
    position: absolute;
    left: 17px;
    top: 43px;
}


.back{
    height: 48px;
    display: block;
    width: 48px;
    color: #002244;
    background: url('../img/back.png') 8px 12px no-repeat white;
    border-radius: 24px;
}
.fbshare{
    float: right;
    margin-top: 10px;
}
.share{
    display: block;
}
.jury div.memeberdetailmobile{
    display: none
}
.clockwrapper p.clock {
    font-size: 90px;
    letter-spacing: 10px;
    display: block;
    width: 100%;
    height: 86px;
    margin: 20px 0 0px;
    line-height: 90px;
}
.clockwrapper p.clock span {
    position: relative;
    top: -10px;
}
.clockwrapper p{
    display: inline-block;
    width: 138px;
    margin: 0 0 40px;
    font-size: 10px;
}
.knowmore{
    margin-bottom: -15px;
}
.countdown .byline {
    padding-top: 4px;
    line-height: 20px;
    letter-spacing: 1px;
}
.submission{
    padding: 38px 77px;
}
.submission.likething{
    padding: 1px;
}
.likething .fb_iframe_widget{
    position: relative;
    top: -7px;
    display: inline!important;
    margin-left: 7px;
    padding: 0;
}

.submission .special p{
    line-height: 0px;
    display: inline;
    font-size: 21px;
}
.submission .special p.likedetails{
    position: relative;
    top: -11px;
    line-height: 0;
    padding: 0;
}
.submission img{
    width: 100%;
    margin-top: 2px;
}
.submission .content{
    text-align: left;
}
.submission .content .left{
    float: left;
    max-width: 381px;
    margin-right: 40px;
    display: inline-block; 
}
.submission .content .entrepreneur .special{
    font-size: 20px;
    margin-bottom: 6px;
}
.submission .content .entrepreneur p{
    font-size: 11px;
    text-transform: none;
}
.submission .content .entrepreneur p.name{
    text-transform: uppercase;
    padding-top: 10px;
    line-height: 0px;
}
.submission .content .entrepreneur{
    padding: 6px;
    display: inline-block;
    width: 206px;
    background: white;
    float: right;
    margin-top: 10px;
}
.submission .special{
    margin: 0 0 6px 0;
}
.submission .content .entrepreneur img{
    width: auto;
    margin-top: 0;
}
.submission .project h2{
    padding-top: 20px;
} 
.submission .project p{
    text-transform: none;
    font-size: 14px;
    margin-top: 4px;
}
.content .quote {
    margin: 50px 0;
}
.content .quote p {
    font-family: PerpetuaMT-Bold;
    font-size: 19px;
    line-height: 1em;
    text-transform: none;
    margin-bottom: 0;
}
.content .quote p.mentor {
    font-size: 11px;
    font-family: GillSansMTStd-Medium;
    text-transform: uppercase;
    padding-top: 13px;
    margin-top: 0;
    text-align: right;
}
.submission .social{
    clear: both;
    height: 82px;
}
.submission .social .socialheader{
    font-family: PerpetuaMT-Bold;
    font-size: 16px;
    margin: 20px 0 1px;
}
.submission .social p{
    color: #e9e2d8;
    margin: 0 60px;
}
.submission .social>div{
    max-width: 315px;
    background-color: #002244;
    float: left;
    display: inline-block;
    height: 82px;
    padding-bottom: 5px;
}
.submission .social .sharebox{
    float: right;
    margin-right: 0
}
.submission .social>.sharebox.wider {
    width: 100%;
}
.submission .social img{
    width: auto;
}
p.likedetails, span.likedetails{
    font-size: 11px !important;
    display: block !important;
    position: relative;
    top: 2px;
}
.social p.likedetails, .social span.likedetails{
    margin: 0;
    margin-top: -5px;
    margin-bottom: 4px;
    font-size: 10px!important;
}
.submission .social .sharebox .socialheader {
    margin: 27px 0 1px 0;
}
.social .fb_iframe_widget{
    padding-top: 0;
}
.faded{
    opacity: .6;
}
/* ==========================================================================
   Media Queries
   ========================================================================== */

@media only screen and (max-width: 651px) {
    .jury div.memeberdetailmobile{
        display: block;
        max-height: 0;
        transition: all .5s;
        overflow: hidden;
    }
    .jury div.memeberdetailmobile.visible{
        max-height: 300px
    }
    .section{
        opacity: 1;
    }
    .jury div{
        opacity: 1;
        display: block;
        width: 100%;
    }
    .memeberdetailswrapper{
        display: none;
    }
    .instruction{
        opacity: 1;
    }
    .mybtn.computerbtn{
        /*display: inline-block;*/
    }
    .mybtn.applybtn{
        /*display: none;*/
    }
    .jury div a{
        margin: 0 auto;
    }
    .jury div p{
        margin: 1em auto 2em auto;
    }
    .documentholder{
        padding: 20px 0;
        width: 33%;
        -moz-box-sizing: border-box;
        box-sizing: border-box;
        margin: 0;
    }
    .documentholder div{
        margin: 0 auto;
        width: 60px;
        height: 60px;
    }
    .documentholder .video {
        background-size: 43px auto;
    }
    .documentholder .photo {
        background-size: 37px auto;
    }
    .documentholder .document {
        background-size: 27px auto;
    }
    .qq-upload-list{
        width: 75%;
        margin: 0 auto;
    }
    .qq-upload-file{
        font-size: 10px;
    }
    #legal{
        bottom: -104px;
        width: 100%;
        font-size: 12px;
    }
    #legal p{
        letter-spacing: 0;
    }
    .apply input, .apply textarea{
        font-size: 11px;
        box-sizing: border-box;
    }
    .apply input[type="submit"]{
        font-size: 16px;
    }
    .footer{
        background-size: contain;
        position: relative;
        bottom: 6px;
    }
    .backwrapper, .backwrapperlast{
        top: 17px;
    }
    .pitch h2{
        padding-top: 24px;
    }
    h2{
        font-size: 23px;

    }
    .thankswrapper h2{
        padding-top: 70px;
    }
    .thankswrapper .share {
       margin-bottom: 0;
    }
    .mobilehide{
        display: none;
    }
    p.offset{
        margin-top: 2em;
    }
    .instruction{
        height: auto;
    }
    .instruction h3{
        margin-top: 1em;
    }
    .instruction,.instruction p,.section.details h3, .instruction .count{
        position: static;
    }
    .instruction .count{
        margin: 0 auto;
    }
    .memberdetails {
        height: auto;
        margin-bottom: 0;
    }
    .fieldset{
        overflow: hidden;
    }
    .footer p{
        font-size: 9px;
    }
    .clockwrapper p.clock {
        font-size: 39px;
        letter-spacing: 4px;
        margin: 0px 0 0px;
        height: 33px;
        line-height: 1em;    
    }
    .clockwrapper p {
        width: 55px;
        margin: -5px 0 24px;
        font-size: 9px;
        text-align: center;
        padding-top: 5px;
        position: relative;
    }
    .days{
        left: -10px;
    }
    .hours{
        left: -5px;
    }
    .min{
        right: -2px;
    }
    .sec{
        right: -6px;
    }
    .clockwrapper p.clock span {
       top: -4px;
    }
    .vote{
        margin: 0 4% 63px 4%;
    }
    .bar{
        width: 100%;
    }
    }
    .bar:hover, .link .bar:hover {
        background: transparent;
    }
    .bar .link{
        width: 92%;
        margin: 0 auto;
    }
    .bar .like{
        width: 206px;
    }
    .vote .special{
        font-size: 11px;
    }
    .submission {
        padding: 57px 17px;
    }
    .submission h1{
        font-size: 26px;
    }
    .submission .special{
        height: auto;
        padding: 12px 9px 0 9px;
    }
    .submission .special p.likedetails{
        line-height: 1em;
        font-size: 10px !important;
    }
    .submission .content .left{
        margin-right: 0;
        text-align: justify;
    }
    .submission .social>div{
        height: auto;
        margin-top: 20px;
        padding: 0 20px;
        max-width: 100%;

    }
    .submission .social .sharebox{
        display: none;
    }
    .submission .content .entrepreneur{
        box-sizing: border-box;
        width: 100%;
    }
    .submission .content .entrepreneur img{
        width: 100%;
    }
}
@media print,
       (-o-min-device-pixel-ratio: 5/4),
       (-webkit-min-device-pixel-ratio: 1.25),
       (min-resolution: 120dpi) {

}

/* ==========================================================================
   Helper classes
   ========================================================================== */

.ir {
    background-color: transparent;
    border: 0;
    overflow: hidden;
    *text-indent: -9999px;
}

.ir:before {
    content: "";
    display: block;
    width: 0;
    height: 150%;
}

.hidden {
    display: none !important;
    visibility: hidden;
}

.visuallyhidden {
    border: 0;
    clip: rect(0 0 0 0);
    height: 1px;
    margin: -1px;
    overflow: hidden;
    padding: 0;
    position: absolute;
    width: 1px;
}

.visuallyhidden.focusable:active,
.visuallyhidden.focusable:focus {
    clip: auto;
    height: auto;
    margin: 0;
    overflow: visible;
    position: static;
    width: auto;
}

.invisible {
    visibility: hidden;
}

.clearfix:before,
.clearfix:after {
    content: " ";
    display: table;
}

.clearfix:after {
    clear: both;
}

.clearfix {
    *zoom: 1;
}

/* ==========================================================================
   Print styles
   ========================================================================== */

@media print {
    * {
        background: transparent !important;
        color: #000 !important; /* Black prints faster: h5bp.com/s */
        box-shadow: none !important;
        text-shadow: none !important;
    }

    a,
    a:visited {
        text-decoration: underline;
    }

    a[href]:after {
        content: " (" attr(href) ")";
    }

    abbr[title]:after {
        content: " (" attr(title) ")";
    }

    /*
     * Don't show links for images, or javascript/internal links
     */

    .ir a:after,
    a[href^="javascript:"]:after,
    a[href^="#"]:after {
        content: "";
    }

    pre,
    blockquote {
        border: 1px solid #999;
        page-break-inside: avoid;
    }

    thead {
        display: table-header-group; /* h5bp.com/t */
    }

    tr,
    img {
        page-break-inside: avoid;
    }

    img {
        max-width: 100% !important;
    }

    @page {
        margin: 0.5cm;
    }

    p,
    h2,
    h3 {
        orphans: 3;
        widows: 3;
    }

    h2,
    h3 {
        page-break-after: avoid;
    }
}

.fb_iframe_widget{
    padding: 5px 0 10px 0;
    height: 12px;
    overflow: hidden;
}

/*preloader*/
body:after{
    display:none;
    content:url('../img/mathieu.jpg') url('../img/hirmane.jpg') url('../img/daniel.jpg');
}
.ieshow{
    display: none;
}
.ng-modal-overlay {
  /* A dark translucent div that covers the whole screen */
  position:absolute;
  z-index:9999;
  top:0;
  left:0;
  width:100%;
  height:100%;
  background-color:#000000;
  opacity: 0.8;
}
.ng-modal-dialog {
  /* A centered div above the overlay with a box shadow. */
  z-index:10000;
  position: absolute;
  width: 100%; /* Default */

  /* Center the dialog */
  top: 30px;
  left: 0;

}
.ng-modal-dialog-content {
  background-color: white;
  box-shadow: 4px 4px 80px #000;
  padding: 20px 40px;
  text-align: left;
  width: 75%;
  margin: 0 auto;
}

.ng-modal-dialog-content p{
    text-transform: inherit;
    font-size: 14px;
    margin-bottom: 30px;
    line-height: 1.3;
}
.ng-modal-dialog-content em{
    text-transform: uppercase;
    display: block;
    margin-bottom: 4px;
    font-family: PerpetuaMT-Bold;
    font-style: normal;
    font-weight: normal;
    font-size: 1.2em;
}
.ng-modal-dialog-content h2{
    text-align: center;
    padding-top: 25px;
    padding-bottom: 10px;
}
.ng-modal-dialog-content img{
    margin-top: 12px;
    width: 100%;
}
.ng-modal-close {
  cursor: pointer;
  display: inline-block;
  font-weight: bold;
  font-family: 'arial', 'sans-serif';
  float: right;

}

---

我在css选择器后面有两个括号，因此关闭了媒体选择器

}
}

---

我不明白你的问题到底是什么，但试着参考下面的内容（我之前的一个答案贴在下面）

将其包含在

中（如果您没有）

现在我试着解释一下……）

对于要应用这些样式的

max width

为

500px

的窗口。在大多数情况下，在这种尺寸下，你会谈论任何比桌面屏幕小的东西

@media screen and (max-width:500px)

对于具有

屏幕

和

最大宽度

为

500px

的窗口的设备，应用样式。这与上述内容几乎相同，只是您指定的是

屏幕

，而最常见的另一个是

打印

@media only screen and (max-width:500px)

这里有一个来自W3C的直截了当的例子来解释这一点

关键字“

only

”也可用于对较旧的用户代理隐藏样式表。用户代理必须处理以“only”开头的媒体查询，就像“only”关键字不存在一样

由于没有像“

only

”这样的媒体类型，旧浏览器应该忽略样式表

我试着把从网上收集的更多信息放在这里

@media all and (min-width: 500px) {
}

@media all and (max-width: 500px) and (min-width: 300px) {
}

@media all and (max-width: 299px) {
}

这就是媒体查询：逻辑if语句。“如果”这些关于浏览器的事情是真的，那么使用里面的CSS

And

关键字和

@media (min-width: 600px) and (max-width: 800px) {
  html { background: red; }
}

Or

逗号分隔

@media (max-width: 600px), (min-width: 800px) {
  html { background: red; }
}

从技术上讲，这些被视为独立的媒体查询，但这实际上是和或

Not

使用关键字not反转逻辑

@media not all and (max-width: 600px) {
  html { background: red; }
}

只是不做（最大宽度：600px）似乎对我不起作用，因此上面的语法有点时髦。也许有人能给我解释一下。请注意，这不仅适用于当前媒体查询，因此如果使用逗号分隔，它只会影响其所在的媒体查询。还请注意，not将整个媒体查询的逻辑作为一个整体反转，而不是反转其各个部分。非x和y=非（x和y）≠ （不是x）和y

独家

要确保一次只执行一个媒体查询，请输入可能的数字（或任何数字）。用这种方式在精神上管理他们可能更容易

@media (max-width: 400px) {
  html { background: red; }
}
@media (min-width: 401px) and (max-width: 800px) {
  html { background: green; }
}
@media (min-width: 801px) {
  html { background: blue; }
}

从逻辑上讲，这有点像switch语句，只是没有一个简单的方法来执行“如果这些匹配项都不执行此操作”，就像默认值一样

覆盖

没有什么可以阻止多个媒体查询同时为真。在某些情况下，使用此选项可能比使它们都具有排他性更有效

@media (min-width: 400px) {
  html { background: red; }
}
@media (min-width: 600px) {
  html { background: green; }
}
@media (min-width: 800px) {
  html { background: blue; }
}

媒体查询对其包含的选择器没有特殊性，但源顺序仍然很重要。以上操作将起作用，因为它们的顺序正确。交换这个顺序，当浏览器窗口宽度超过800px时，背景将是红色的，也许是好奇的

移动优先

您的小屏幕样式在常规屏幕CSS中，然后随着屏幕变大，您将覆盖您需要的内容。因此，一般来说，最小宽度的媒体查询

html { background: red; }

@media (min-width: 600px) {
  html { background: green; }
}

html { background: red; }

@media (max-width: 600px) {
  html { background: green; }
}

桌面优先

您的大屏幕样式在常规屏幕CSS中，然后随着屏幕变小，您将覆盖所需的内容。因此，一般来说，最大宽度媒体查询

html { background: red; }

@media (min-width: 600px) {
  html { background: green; }
}

html { background: red; }

@media (max-width: 600px) {
  html { background: green; }
}

你可以想怎么复杂就怎么复杂

@media 
  only screen and (min-width: 100px),
  not all and (min-width: 100px),
  not print and (min-height: 100px),
  (color),
  (min-height: 100px) and (max-height: 1000px),
  handheld and (orientation: landscape)
{
  html { background: red; }
}

注意，唯一的关键字是为了防止非媒体查询支持的浏览器不加载样式表或使用样式。不知道那曾经/现在有多有用

资料来源：

html { background: red; }

@media (max-width: 600px) {
  html { background: green; }
}

@media 
  only screen and (min-width: 100px),
  not all and (min-width: 100px),
  not print and (min-height: 100px),
  (color),
  (min-height: 100px) and (max-height: 1000px),
  handheld and (orientation: landscape)
{
  html { background: red; }
}