Cod barra

gistfile1.txt

.barra-scroll
  .container
    nav.nav-header
      ul
        li
          a.bt-menu href="#"
            i.fa.fa-bars
            |  MENU
        li
          form.form-search
            i.fa.fa-search
            input type="text" id="dad" placeholder="buscar"
            button type="submit"
              i.fa.fa-chevron-right
        li.right
          a href="login.html"
            i.fa.fa-plus
            span  CADASTRAR
        li.right
          a.bt-login href="login.html"
            i.fa.fa-user
            span  ENTRAR


.barra-scroll
  padding: .8em
  padding-bottom: .2em
  width: 100%
  background: $bege + 10 url(/assets/images/logo-small.jpg)  center no-repeat
  border-bottom: 2px solid $bege
  opacity: 0
  top: 0
  position: fixed
  z-index: 1
  +prefixed(transition, .5s)
  ul
    margin: 0
    padding: 0
    li
      font-size: .8em
      display: inline-table
      top: -5px
      padding-right: 10px
      position: relative
      a
        letter-spacing: 1px
        &:hover
          color: $verde
        i
          color: $verde

.active
  position: fixed
  opacity: 1
  top: 0

javascript:
          
          var mainbottom = $('.logo-header').offset().top + $('.logo-header').height();

          // on scroll,
          $(window).on('scroll',function(){

              
              stop = Math.round($(window).scrollTop());
              if (stop > mainbottom) {
                  $('.barra-scroll').addClass('active');
              } else {
                  $('.barra-scroll').removeClass('active');
             }

          });