element.style {
}
@media only screen and (max-width: 767px)
.header, .headerText, #main {
    width: auto;
}
.header {
    height: 280px;
    background-image: url(https://images2018.cnblogs.com/blog/1384700/201805/1384700-20180507200746425-1272159424.jpg);
    background-repeat: no-repeat;
    background-position: left;
    border: 0px dotted #000000;
    padding-left: 0px;
    padding-top: 0px;
    margin-left: 0px;
    width: 850px;
    padding-bottom: 0px;
}

user agent stylesheet
div {
    display: block;
}
element.style {
}
a.headermaintitle:visited, a.headermaintitle:active, a.headermaintitle:link {
    color: #ccc;
    font-size: 66px;
    font-weight: bold;
    text-decoration: none;
}