edx-platform/sass/_courseware.scss

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

  ul, ol {
    list-style: none;
  }

  .tran {
    @include transition( all, .2s, $ease-in-out-quad);
  }

  section.course-index {
    @extend .sidebar;
    position: relative;
    @extend .tran;

    div#open_close_accordion {
    @include box-shadow(0 1px 0 #eee);
    border-bottom: 1px solid #d3d3d3;
      padding: 0 lh() 4px;

      h2 {
        padding-right: 20px;
      }

      a {
        width: 16px;
        text-indent: -9999px;
        height: 16px;
        position: absolute;
        padding: 8px;
        top: 12px;
        right: -1px;
        border: 1px solid #D3D3D3;
        background: #eee url('/static/images/slide-left-icon.png') center center no-repeat;
        @include box-shadow(0 0 0 1px #fff);
        @include border-radius(3px 0 0 3px);

        &:hover {
          background-color: white;
        }
      }
    }

    div#accordion {

      h3 {
        overflow: hidden;
        margin: 0;

        &:last-child {
          @include box-shadow(none);
        }

        &.ui-accordion-header {
          color: #000;

          a {
            font-size: $body-font-size;
            color: lighten($text-color, 10%);
          }

          &.ui-state-hover {
            border: none;
            border-bottom: 1px solid #d3d3d3;
          }

          &.ui-state-active {
            @extend .active;
          }
        }
      }

      ul.ui-accordion-content {
        @include border-radius(0);
        @include box-shadow( inset -1px 0 0 #e6e6e6);
        background: #d6d6d6;
        border: none;
        border-bottom: 1px solid #c3c3c3;
        font-size: 12px;
        margin: 0;
        overflow: hidden;

        li {
          &.active {
            font-weight: bold;
          }

          a {
            text-decoration: none;
            margin-bottom: lh(.5);
            display: block;
            color: #000;

            &:hover {
              color: #666;
            }

            p {
              margin-bottom: 0;

              &.subtitle {
                color: #666;
              }
            }
          }
        }
      }
    }
  }
  

  section.course-content {
    @extend .content;

    p {
      margin-bottom: lh();

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

    .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 dotted #ccc;
        @include box-sizing(border-box);
        display: table-cell;
        vertical-align: top;

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

        span {
          &.unanswered, &.ui-icon-bullet {
            @include inline-block();
            background: url('/static/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('/static/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('/static/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;
      }
    }

    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;
        }
      }
    }
  }

  &.closed {
    section.course-index {
      width: flex-grid(.6);
      padding-left: 4px;

    div#open_close_accordion {
      a {
        background-image: url('/static/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();
    }
  }
}