edx-platform/static/css/courseware/_courseware.scss

div.course-wrapper {
  @extend .table-wrapper;

  ul, ol {
    list-style: none;
  }

  section.course-content {
    @extend .content;

    h1 {
      @extend .top-header;
    }

    p {
      margin-bottom: lh();

      &:empty {
        display: none;
        margin-bottom: 0;
      }
    }

    ul {
      li {
        margin-bottom: lh(.5);
      }
    }

    .problem-set {
      position: relative;
      @extend .clearfix;

      h2 {
        margin-top: 0;
        margin-bottom: 15px;
        width: flex-grid(2, 9);
        padding-right: flex-gutter(9);
        border-right: 1px dashed #ddd;
        @include box-sizing(border-box);
        display: table-cell;
        vertical-align: top;

        @media screen and (max-width:1120px) {
          display: block;
          width: auto;
          border-right: 0;
        }

        @media print {
          display: block;
          width: auto;
          border-right: 0;
        }
      }

      section.problem {
        display: table-cell;
        width: flex-grid(7, 9);
        padding-left: flex-gutter(9);

        @media screen and (max-width:1120px) {
          display: block;
          width: auto;
          padding: 0;
        }

        @media print {
          display: block;
          width: auto;
          padding: 0;

          canvas, img {
            page-break-inside: avoid;
          }
        }

        span {
          &.unanswered, &.ui-icon-bullet {
            @include inline-block();
            background: url('../images/unanswered-icon.png') center center no-repeat;
            height: 14px;
            position: relative;
            top: 4px;
            width: 14px;
          }

          &.correct, &.ui-icon-check {
            @include inline-block();
            background: url('../images/correct-icon.png') center center no-repeat;
            height: 20px;
            position: relative;
            top: 6px;
            width: 25px;
          }

          &.incorrect, &.ui-icon-close {
            @include inline-block();
            background: url('../images/incorrect-icon.png') center center no-repeat;
            height: 20px;
            width: 20px;
            position: relative;
            top: 6px;
          }
        }
      }

      div {
        > span {
          display: block;
          margin-bottom: lh(.5);
        }
      }

      input[type="text"] {
        display: inline-block;
      }

      center {
        display: block;
        margin: lh() 0;
        border: 1px solid #ccc;
        padding: lh();
      }

      section.action {
        margin-top: lh();
      }
    }

    section.problems-wrapper, div#seq_content {
      @extend .problem-set;
    }

    section.problems-wrapper {
      display: table;
      width: 100%;

      @media screen and (max-width:1120px) {
        display: block;
        width: auto;
      }
    }

    div#seq_content {
      h1 {
        background: none;
        margin-bottom: lh();
        padding-bottom: 0;
        border-bottom: none;
      }
    }

    ol.vert-mod {
      > li {
        @extend .clearfix;
        @extend .problem-set;
        border-bottom: 1px solid #ddd;
        margin-bottom: 15px;
        padding: 0 0 15px;

        &:last-child {
          border-bottom: none;
          margin-bottom: 0;
          padding-bottom: 0;
        }
      }
    }

    section.tutorials {
      ul {
        list-style: disc outside none;
        margin-left: lh();
      }
    }

    div.staff_info {
      @include clearfix();
      white-space: pre-wrap;
      border-top: 1px solid #ccc;
      padding-top: lh();
      margin-top: lh();
      line-height: lh();
      font-family: Consolas, "Lucida Console", Monaco, "Courier New", Courier, monospace;
    }

    div.ui-slider {
      border: 1px solid #aaa;
      background: #ddd;
      @include box-shadow(inset 0 1px 0 #eee);
      @include border-radius(0);

      a.ui-slider-handle {
        @include box-shadow(inset 0 1px 0 lighten($mit-red, 10%));
        background: $mit-red url(../images/slider-bars.png) center center no-repeat;
        border: 1px solid darken($mit-red, 20%);
        cursor: pointer;

        &:hover, &:focus {
          background-color: lighten($mit-red, 10%);
          outline: none;
        }
      }
    }
  }

  &.closed {
    section.course-index {
      width: flex-grid(.6);

      header#open_close_accordion {
        padding: 0;

        a {
          background-image: url('../images/slide-right-icon.png');
        }

        h2 {
          visibility: hidden;
          width: 10px;
          padding: 0;
        }
      }

      div#accordion {
        visibility: hidden;
        width: 10px;
        padding: 0;
      }
    }

    section.course-content {
      width: flex-grid(11.5) + flex-gutter();
    }
  }
}