discourse/app/assets/stylesheets/desktop/modal.scss

// Hardcode to be the same as before for now. I would recommend not using bootbox, or finding a way so the html structure can be the same
.bootbox.modal {
  top: 50%;
  left: 50%;
  width: 610px;
  margin: -250px 0 0 -305px;
  .cancel {
    margin-left: 1em;
  }
}

.modal.in {
  -webkit-animation: fade 0.25s;
  animation: fade 0.25s;
}

.modal-footer .btn.right {
  float: right;
}

.modal-header {
  h3 {
    font-size: $font-up-3;
  }
}

.close {
  font-size: $font-up-3;
  text-decoration: none;
  &:visited {
    color: var(--primary-high);
  }
  cursor: pointer;
  &:hover {
    color: var(--primary);
  }
}

.modal {
  .category-chooser {
    width: 50%;
  }

  .modal-body.insert-link {
    input {
      min-width: 450px;
    }
  }
}

.choose-topic-modal {
  .modal-body {
    position: relative;
    height: 350px;
  }

  #choosing-topic {
    // prevents content from moving when user selects different move options 525px
    // is the same width we set on category edit modal
    width: 525px;

    p {
      margin-top: 0;
    }

    .radios {
      margin-bottom: 10px;
      display: flex;
      flex-direction: row;

      .radio-label {
        display: inline-block;
        padding-right: 15px;
      }
    }

    button {
      margin-top: 10px;
      display: block;
      width: 300px;
    }

    form {
      width: 95%;
      margin-top: 20px;

      .participant-selector {
        width: 100%;
      }

      div.ac-wrap {
        width: 100%;
        margin-bottom: 9px;
      }
    }
  }
}

.change-post-notice-modal {
  .modal-body {
    min-width: 450px;
  }
}

.json-schema-editor-modal {
  #json-editor-holder {
    min-width: 500px;
  }
}

.create-invite-modal,
.create-invite-bulk-modal,
.share-topic-modal {
  .modal-inner-container {
    width: 40em; // scale with user font-size
    max-width: 100vw; // prevent overflow if user font-size is enourmous
  }
}