styles.css

.cell-output pre {
    margin-left: 0.8rem;
    margin-top: 0;
    background: none;
    border-left: 2px solid lightsalmon;
    border-top-left-radius: 0;
    border-top-right-radius: 0;
  }
  
  .cell-output .sourceCode {
    background: none;
    margin-top: 0;
  }
  
  .cell > .sourceCode {
    margin-bottom: 0;
  }