gui/src/plugins/bootstrap/dark-theme.scss
// Required
@import 'bootstrap/scss/functions';
@import 'bootstrap/scss/variables';
@import 'bootstrap/scss/mixins';

.dark-theme {
  // General
  .main-body {
    background-color: $gray-900;
    color: $gray-400;
  }

  strong,
  label,
  div,
  p {
    color: $gray-400;
  }

  .btn {
    color: $gray-400;
  }

  // Forms
  input.form-control,
  select.form-select,
  textarea.form-control {
    background-color: $gray-900;
    color: $gray-400;
    border-color: $gray-700;
  }

  input.form-check-input {
    background-color: $gray-900;
    border-color: $gray-700;
  }

  input.form-control::placeholder {
    color: $gray-400;
  }

  // Accordion
  .accordion-item,
  .accordion-button {
    background-color: $gray-900;
    color: $gray-400;
    border-color: $gray-700;
  }

  .accordion-button {
    box-shadow: none;
  }

  // Lists
  .list-group .list-group-item {
    background-color: $gray-900;
    color: $gray-400;
    border-color: $gray-700;
  }

  // Table
  .table {
    color: $gray-400;

    tr td {
      color: $gray-400;
      border-color: $gray-700;
      background-color: $gray-900;
    }
  }

  // Modals
  .modal-content {
    background-color: $gray-900;

    .btn.btn-secondary {
      color: $gray-900;
    }
  }

  // Cards
  .card-body {
    background-color: $gray-900;
  }

  .card {
    border-color: $gray-700;
    overflow: hidden;
  }

  // Other
  .divider {
    border-bottom: 1px solid $gray-400;
  }
}
