html, 
body, 
h1, 
h2, 
h3, 
h4, 
h5 { 
    font-family: "Open Sans", "Helvetica Neue", Helvetica, "Hiragino Sans GB", "Hiragino Kaku Gothic Pro", "ヒラギノ角ゴ Pro W3", "noto sans", "source Han Sans", "Microsoft Yahei", "微软雅黑", "Microsoft JhengHei", "微軟正黑體", sans-serif; 
    font-weight: 400; 
}
* {
    box-sizing: border-box;
}
a {
    color: #ffffff;
    text-decoration: none;
}
a:hover {
    color: #ffffff;
    /* text-decoration: underline; */
}
.clearfix:before,
.clearfix:after {
    content: " ";
    display: table;
}
.clearfix:after {
    clear: both;
}

.tc {
    text-align: center;
}
html {
    line-height: 1.5;
    height: 100%;
    background: -webkit-linear-gradient(left, #1E2127 , #3D424D); /* Safari 5.1 - 6.0 */
    background: -o-linear-gradient(right, #1E2127, #3D424D); /* Opera 11.1 - 12.0 */
    background: -moz-linear-gradient(right, #1E2127, #3D424D); /* Firefox 3.6 - 15 */
    background: linear-gradient(to right, #1E2127 , #3D424D); /* 标准的语法 */
}
body {
    margin: 0;
    color: #ffffff;
    font-size: 14px;
}

footer {
    padding: 10px;
}

/* header start */
.header {
    padding: 15px 20px;
    display: flex;
    align-items: center;
    justify-content: flex-end;
}
.header-item {
    margin: 0 20px;
    display: flex;
    flex-flow: column;
    align-items: flex-end;
    justify-content: center;
}
.header-item a {
    text-decoration: underline;
	font-size: 18px;
}
a.header-language {
    text-decoration: none;
    padding: 10px 10px;
    border: 1px solid #ffffff;
    border-radius: 50%;
}
/* header end */

.container {
    width: 100%;
    margin: 50px auto;
    max-width: 1050px;
}

/* box */
.box {
    display: flex;
    justify-content: center;
}
.box-item {
    flex: 1;
    max-width: 300px;
    min-width: 260px;
    height: 350px;
    margin: 10px;
    background-color: rgba(66, 69, 77, 1);
    position: relative;
    overflow: hidden;
    border-radius: 10px;
    box-shadow: 0 2px 20px 0px rgba(22, 20, 20, 0.3);
}
.box-item-cont {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    transition: all 600ms ease;
}
.box-item-pane {
    opacity: 0;
    position: absolute;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(66, 70, 78, 0);
    color: #ffffff;
    transform: translateY(100%);
    z-index: -1;
    transition: all 600ms ease;
}
.box-item-pane ul {
    padding-left: 30px;
    padding-right: 30px;
}
.box-item-pane ul li {
    list-style: none;
    height: 40px;
    line-height: 40px;
    margin-bottom: 10px;
    border-radius: 4px;
    background-color: rgba(130, 133, 140, 1);
    padding-left: 10px;
    position: relative;
    transition: all 500ms ease;
}
.box-item-pane ul li:hover {
    background-color: rgba(38, 41, 48, 1)
}
.box-item-pane ul li span {
    position: absolute;
    z-index: 1;
    left: 10px;
    top: 0px;
    bottom: 0px;
    font-weight: bold;
    font-size: 16px;
}
.box-item-pane ul li a {
    display: inline-block;
    width: 100%;
    color: #ffffff;
    text-align: left;
    padding-left: 16px;
    height: 40px;
    line-height: 40px;
}
.box-item-pane ul li a img {
    display: block;
    height: 22px;
    margin-top: 9px;
}
.box-item-pane ul li a img.small {
    height: 28px;
    margin-top: 6px;
}
.box-logo {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    text-align: center;
    transition: all 600ms ease;
}
.box-logo img {
    display: block;
    width: 180px;
    height: auto;
    transition: all 600ms ease;
}
.box-logo img.light {
    display: block;
}
.box-logo img.dark {
    display: none;
}
.box-item:hover .box-item-cont {
    background-color: rgba(211, 211, 223, 1);
    top: 0;
    transform: translate(-50%, 0);
}
.box-item:hover .box-logo {
    height: 60px;
}
.box-item:hover .box-logo img.light {
    display: none;
}
.box-item:hover .box-logo img.dark {
    display: block;
    width: auto;
    height: 44px;
}
.box-item:hover .box-item-pane {
    opacity: 1;
    z-index: 1;
    background-color: rgba(95, 99, 108, 1);
    transform: translateY(60px);
}

@media (max-width: 830px) {
    .box {
        flex-flow: column;
        align-items: center;
    }
    .box-item {
        flex: none;
    }
}

/* links */
.links {
    margin-top: 50px;
    padding: 10px 0;
    text-align: center;
}
.btn {
    display: inline-block;
    font-size: 16px;
    padding: 15px 30px;
    border: 1px solid rgba(211, 211, 223, 1);
    border-radius: 5px;
    transition: all 300ms ease;
}
.btn:hover {
    text-decoration: none !important;
    color: #000000;
    background-color: rgba(211, 211, 223, 1);
    box-shadow: 3px 3px 10px rgba(0, 0, 0, 0.9)
}