/**** 默认主题 ****/
        .ColorTheme {
            --bgcolor-header: #0099ff;
            --color-header: #ffffff;
            --bgcolor-hover-headerNav: #33ccff;
            --bgcolor-header-groundtop: #99ccff;
        }

        body {
            margin: 0;
            -ms-text-size-adjust: none;
              -webkit-text-size-adjust: none;
                -moz-text-size-adjust: none;
                  text-size-adjust: none;
        }

        header {
            background-color: var(--bgcolor-header);
            color: var(--color-header);
        }

        header h1 {
            float: left;
            font-size: 2em;
            width: 8em;
            margin: 0;
            padding: 0.67em;
        }

        header nav {
            float: right;
        }

        header nav a {
            color: var(--color-header);
            text-decoration: none;
            display: block;
            float: left;
            font-size: 1em;
            margin: 0 0.5em;
            padding: 0.4em 0.8em;
            border-radius: 0 0 0.8em 0.8em;
        }

        header nav a:hover {
            background-color: var(--bgcolor-hover-headerNav);
        }

        header time {
            float: right;
            clear: right;
            padding: 1.2em 3em;
            font-size: 0.8em;
        }

        header #groundTop {
            min-height: 0.6em;
            background-color: var(--bgcolor-header-groundtop);
            clear: both;
        }
        
        .con_center {
            margin: 1.6em auto;
            width: 960px;
        }
        
        .con_center_button {
            display: block;
            text-decoration: none;
            float: left;
            height: 210px;
            width: 470px;
            margin-right: 10px;
            margin-bottom: 10px;
            background-color: #e8ebf0;
            color:#000000;
            text-align: center;
            line-height: 210px;
            font-size: 24px;
        }
        
        .con_center_button:hover {
            background-color: #acc6f1;
        }

        footer {
            text-align: center;
            font-size: 0.8em;
        }