app.css

    .hidden.menu {
      display: none;
    }

    .masthead.segment {
      min-height: 500px;
      padding: 1em 0em;
      background-image: url(https://cosmicjs.com/uploads/0e5a4fd0-5abc-11e6-8f51-55bd82b62d3b-cosmic-js-dark.jpg) !important;
      background-size: cover !important;
      background-position: center !important;
      color: #fff !important;
      overflow: hidden !important;
    }
    .masthead .logo.item img {
      margin-right: 1em;
    }
    .masthead .ui.menu .ui.button {
      margin-left: 0.5em;
    }
    .masthead h1.ui.header {
      margin-top: 1.5em;
      margin-bottom: 0em;
      font-size: 4em;
      font-weight: normal;
    }
    .masthead h2 {
      font-size: 1.7em;
      font-weight: normal;
    }
    .ui.vertical.stripe {
      padding: 4em 0em;
    }
    .ui.vertical.stripe h3 {
      font-size: 2em;
    }
    .ui.vertical.stripe .button + h3,
    .ui.vertical.stripe p + h3 {
      margin-top: 3em;
    }
    .ui.vertical.stripe .floated.image {
      clear: both;
    }
    .ui.vertical.stripe p {
      font-size: 1.33em;
    }
    .ui.vertical.stripe .horizontal.divider {
      margin: 3em 0em;
    }

    .quote.stripe.segment {
      padding: 0em;
    }
    .quote.stripe.segment .grid .column {
      padding-top: 5em;
      padding-bottom: 5em;
    }

    .footer.segment {
      padding: 4em 0em;
    }

    .secondary.pointing.menu .toc.item {
      display: none;
    }

    .ui.link.cards.speakers {
      margin-left: auto;
      margin-right: auto;
    }

    .ui.center.aligned.header.speakers {
      margin-bottom: 1.5em;
    }

    .ui.center.aligned.header.sponsors {
        margin-top: 1.0em;
        margin-bottom: 1.0em;
    }

    .ui.images.sponsors img {
        filter: gray;
        -webkit-filter: grayscale(100%);
        -webkit-backface-visibility: hidden;
    }
    .ui.images.sponsors img:hover {
        filter: none;
        -webkit-filter: none;
        -webkit-backface-visibility: hidden;
    }

    .ui.center.aligned.header.pythoners {
        margin-bottom: 1.0em;
    }

    .ui.container.pythoners a {
        margin-top: 0.5em;
    }


    @media only screen and (max-width: 700px) {
      .ui.fixed.menu {
        display: none !important;
      }
      .secondary.pointing.menu .item,
      .secondary.pointing.menu .menu {
        display: none;
      }
      .secondary.pointing.menu .toc.item {
        display: block;
      }
      .masthead.segment {
        min-height: 350px;
      }
      .masthead h1.ui.header {
        font-size: 2em;
        margin-top: 1.5em;
      }
      .masthead h2 {
        margin-top: 0.5em;
        font-size: 1.5em;
      }
    }