header {
    &>div {
        padding: 2rem 1rem;

        // different padding when screen size below width-md(768px)
        @media screen and (max-width: $width-md) {
            padding: 2rem 1.5rem;
        }
    }

    .sub-title {
        font-size: $font-size-l3;
        display: block;
        color: $color-mute;
    }

    border-bottom: $spliter;
}