discourse/app/assets/stylesheets/common/admin/suspend.scss

.suspend-user-modal {
  .until-controls {
    margin-bottom: 1em;
  }

  .suspend-reason {
    width: 100%;

    &.combo-box {
      margin-bottom: 9px;
    }
  }

  .suspend-reason-label,
  .suspend-message-label {
    margin-bottom: 0.5em;
  }

  .textarea,
  input[type="text"] {
    box-sizing: border-box;
    height: 2.5em;
  }

  .inline-spinner {
    float: right;
  }
}

.modal-body {
  .penalty-post-edit {
    margin-top: 1em;

    textarea {
      height: 10em;
    }
  }
}