.task-submission-wizard
  .large-notice-block .icons-for-files {
    i {
      margin: 0 0.25ex;
    }
  }
  .upload-type-selected-state {
    height: 100%;
    .upload-assistant {
      padding-bottom: 1.25em;
      margin-bottom: 2em;
      border-bottom: 1px solid #ddd;
      h3 {
        float: left;
        font-size: 2em;
        small {
          margin-top: 0.5em;
          font-weight: lighter;
          display: block;
        }
      }
      .upload-type-switcher {
        float: right;
        text-align: right;
        p {
          margin-top: 0.75em;
        }
      }
    }

    .file-uploader {
      text-align: center;
      &.is-uploading {
        margin: 0;
        height: 100%;
        display: block;
        @include flex-center;
      }
      .file-drop-area, .upload-area, .result-area {
        margin: 0 auto;
        width: 50%;
      }
    }
  }
}

.task-submission-wizard {
  .large-notice-block .icons-for-files {
    i {
      margin: 0 0.25ex;
    }
  }
  .upload-type-selected-state {
    height: 100%;
    .upload-assistant {
      padding-bottom: 1.25em;
      margin-bottom: 2em;
      border-bottom: 1px solid #ddd;
      h3 {
        float: left;
        font-size: 2em;
        small {
          margin-top: 0.5em;
          font-weight: lighter;
          display: block;
        }
      }
      .upload-type-switcher {
        float: right;
        text-align: right;
        p {
          margin-top: 0.75em;
        }
      }
    }

    .file-uploader {
      text-align: center;
      &.is-uploading {
        margin: 0;
        height: 100%;
        display: block;
        @include flex-center;
      }
      .file-drop-area, .upload-area, .result-area {
        margin: 0 auto;
        width: 50%;
      }
    }
  }
}

Add missing brace for CSS selector
FIX: Add missing brace for CSS selector
