.kb-404 {
    display: flex;
    align-items: center;
    height: 80vh;
    background: none;
    background: #efefef;
    margin-top:8vh;
}

    .kb-404 .kb-err {
        width: auto;
        margin: 0 auto;
        padding: 0 10% 1%
    }

        .kb-404 .kb-err img {
            width: 100%;
            height: 200px;
            margin-top: -30px;
        }

        .kb-404 .kb-err .txt {
            text-align: center;
            width: 300px;
            margin: 0 auto
        }

            .kb-404 .kb-err .txt .cn {
                font-size: 16px;
                color: #333;
                line-height: 40px
            }

        .kb-404 .kb-err .tt {
            text-align: center;
            width: 300px;
            margin: auto;
            margin-top: 20px;
        }

        .kb-404 .kb-err .btn {
            margin: 25px auto 0;
            width: 200px;
            height: 56px;
            line-height: 56px;
            cursor: pointer;
            font-size: 14px;
            background: #efefef;
            border: 1px solid #eb0028;
            -moz-border-radius: 2px;
            -webkit-border-radius: 2px;
            border-radius: 2px;
            -moz-transition: color .15s ease 0s;
            -o-transition: color .15s ease 0s;
            -webkit-transition-delay: 0s;
            transition: color .15s ease 0s;
            position: relative;
            display: block;
            color: #eb0028;
            z-index: 0
        }

        .kb-404 .kb-err .btn {
            height: 50px;
            max-width: 200px;
            background: none;
            color: #eb0028;
            line-height: 48px;
            font-size: 16px;
            margin: 50px auto 0;
            text-align: center;
        }

            .kb-404 .kb-err .btn:hover {
                color: #d70226;
            }

            .kb-404 .kb-err .btn:before {
                content: none;
            }

@media screen and (max-width: 600px) {
    .kb-404 {
        margin-top: 0;
    }
}