@mixin schnitzel-responsive {
  @media only screen and (max-width: 640px) {
    body {
      padding-bottom: 10px;
    }

    // container overrides
    .container {
      width: auto;

      &>header {
        margin-top: 0 !important;
        padding: 0 10px;
        font-size: 100%;

        .site-title {
          font-size: 100%;

          display: block;
          margin-left: -10px;
          margin-right: -10px;
        }
      }

      &>section, &>article {
        padding-left: 10px;
        padding-right: 10px;
      }
    }

    // content overrides
    article, section {
      margin-top: 10px;

      h1, h2, h3, h4, h5, h6 {
        display: block;
        margin-left: -10px;
        margin-right: -10px;
      }
    }

    // grid overrides
    .column, .columns {
      width: 100% !important;
      float: none !important;
    }
  }
}

@mixin schnitzel-responsive {
  @media only screen and (max-width: 640px) {
    body {
      padding-bottom: 10px;
    }

    // container overrides
    .container {
      width: auto;

      &>header {
        margin-top: 0 !important;
        padding: 0 10px;
        font-size: 100%;

        .site-title {
          font-size: 100%;

          display: block;
          margin-left: -10px;
          margin-right: -10px;
        }
      }

      &>section, &>article {
        padding-left: 10px;
        padding-right: 10px;
      }
    }

    // content overrides
    article, section {
      margin-top: 10px;

      h1, h2 {
        display: block;
        margin-left: -10px;
        margin-right: -10px;
      }
    }

    // grid overrides
    .column, .columns {
      width: 100% !important;
      float: none !important;
    }
  }
}

Fix headings in responsive mode.
Fix headings in responsive mode.