plugins/CoreVisualizations/vue/src/MetricsPicker/MetricsPicker.less

.metrics-picker {
  // Declared inside the selector so they stay scoped to .metrics-picker.
  @_dropdown-shadow: ~"0 10px 40px 0 #A5B1CA4D, 0 0 3px 0 #A5B1CA4D";
  @_dropdown-shadow-dark: ~"0 10px 40px 0 #00000080, 0 0 3px 0 #00000080";

  // 1px solid — shared by the toggle/dropdown/checkbox borders and the focus outline
  @_border-stroke: ~"1px solid";
  @_border: ~"@{_border-stroke} @{theme-color-border-alternative}";

  // hover, and focus states
  @_accent-color: @theme-color-focus-ring;
  @_option-hover-bg: @theme-color-background-base;
  // checked state
  @_checked-color: @theme-color-new-brand;

  @_border-radius: 8px;
  @_checkbox-size: 18px;
  @_checkbox-border-radius: 6px;
  @_text-size: 14px;
  @_text-line-height: 20px;

  display: inline-block;
  position: relative;

  // In a narrow legend footer the picker stacks onto its own full-width row, so the
  // component stretches to fill it. The inline-block wrapper around this component is
  // widened separately in dataTableVisualizations.less (it lives outside this component).
  .jqplot-legend-footer.is-narrow & {
    width: 100%;
  }

  .metrics-picker__toggle {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    background: @theme-color-background-contrast;
    color: @theme-color-text;
    border: @_border;
    border-radius: @_border-radius;
    font-size: @_text-size;
    line-height: @_text-line-height;
    cursor: pointer;
    height: 38px;

    &:hover, &:focus-visible {
      border-color: @_accent-color;
    }
    &:focus-visible {
      outline: @_border-stroke @_accent-color;
    }

    &:focus, &:hover {
      outline: none;
    }

    // In a narrow legend footer the toggle fills its full-width row and centres its label.
    .jqplot-legend-footer.is-narrow & {
      width: 100%;
      justify-content: center;
    }
  }
  .metrics-picker__toggle-label {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    min-width: 0;        // the important one — see below
  }

  .metrics-picker__chevron {
    font-size: 12px;
    transition: transform .15s ease;
    flex: none;      // keep the chevron from being squashed
  }

  &.expanded .metrics-picker__chevron {
    transform: rotate(180deg);
  }

  .metrics-picker__dropdown {
    display: none;
    position: absolute;
    top: 100%;
    margin-top: 8px;
    left: 0;
    z-index: 1010; /* must be above ui dialog, matches series picker popover */
    overflow-y: auto;
    padding: 8px;
    /* the legend footer lives inside .dataTableFeatures (text-align: center) -
       reset so the metric checkboxes align to the left */
    text-align: left;
    background: @theme-color-background-contrast;
    border: @_border;
    border-radius: @_border-radius;
    box-shadow: @_dropdown-shadow;

    .inDarkMode({
      box-shadow: @_dropdown-shadow-dark;
    })
  }

  &.expanded .metrics-picker__dropdown {
    display: block;
    width: 254px;
  }

  .metrics-picker__column,
  .metrics-picker__row {
    padding: 2px 8px;
    cursor: pointer;
  }

  .metrics-picker__label {
    display: flex;
    align-items: flex-start;
    min-height: 32px;
    color: @theme-color-text-lighter;
    border-radius: 5px;
  }

  // hover just tints the option's background
  .metrics-picker__label:hover {
    background-color: @_option-hover-bg;
  }

  // keyboard navigation also draws a focus ring (the real radio/checkbox is visually
  // hidden by .filled-in, so the affordance lives on the option itself)
  .metrics-picker__label:has(input:focus-visible) {
    background-color: @_option-hover-bg;
    outline: 2px solid @_accent-color;
    outline-offset: 0;
  }

  // Materialize gives both the checkbox and radio "+ span" a padding-left: 35px; reset it
  // to a compact box so the marker sits tight against the title in either select mode.
  [type="checkbox"] + span:not(.lever),
  [type="radio"] + span:not(.lever) {
    width: @_checkbox-size;
    height: @_checkbox-size;
    padding: 0;
    margin-top: 4px;
  }

  .metrics-picker__title {
    font-size: @_text-size;
    line-height: @_text-line-height;
    margin-left: 8px;
    overflow-wrap: anywhere;
    word-break: break-word;
    margin-top: 3px;
  }

  [type="checkbox"].filled-in:checked + span:not(.lever)::after {
    border-color: @_checked-color;
    background-color: @_checked-color;
  }

  // The check
  [type="checkbox"].filled-in:checked + span:not(.lever)::before {
    border-right-color: @color-white;
    border-bottom-color: @color-white;
    width: 7px;
    height: 10px;
  }
  [type="checkbox"].filled-in:not(:checked) + span:not(.lever)::after {
    border: @_border;
  }

  /* compact 18px box with rounded corners (Materialize defaults to 20px / 2px) */
  [type="checkbox"].filled-in:checked + span:not(.lever)::after,
  [type="checkbox"].filled-in:not(:checked) + span:not(.lever)::after {
    width: @_checkbox-size;
    height: @_checkbox-size;
    border-radius: @_checkbox-border-radius;
  }

  // Radio marker — match the checkbox box: a 18px circle aligned to the same top-left
  // origin (Materialize insets the circle by margin: 4px and sizes it 16px), with the
  // same border colour when empty and accent fill when selected.
  [type="radio"] + span:not(.lever)::before,
  [type="radio"] + span:not(.lever)::after {
    margin: 0;
    width: @_checkbox-size;
    height: @_checkbox-size;
  }

  [type="radio"]:not(:checked) + span:not(.lever)::before {
    border: @_border;
  }

  [type="radio"]:checked + span:not(.lever)::after {
    border-color: @_checked-color;
    background-color: @_checked-color;
  }

  // The option's focus affordance is the label outline (see
  // .metrics-picker__label:has(input:focus-visible)). Neutralise Materialize's per-marker
  // focus styling — the 10px halo, grey/secondary fill and squared corners it adds on
  // .tabbed:focus — so the box/circle looks identical whether focused or not.
  [type="checkbox"].filled-in.tabbed:focus + span:not(.lever)::after,
  [type="radio"].tabbed:focus + span:not(.lever)::before {
    box-shadow: none;
  }

  [type="checkbox"].filled-in:not(:checked).tabbed:focus + span:not(.lever)::after {
    border: @_border;
    border-radius: @_checkbox-border-radius;
    background-color: transparent;
  }

  [type="checkbox"].filled-in:checked.tabbed:focus + span:not(.lever)::after {
    border-color: @_checked-color;
    background-color: @_checked-color;
    border-radius: @_checkbox-border-radius;
  }

  .metrics-picker__headline {
    margin: 0; // reset the default <p> margin
    padding: 10px 16px 4px;
    font-weight: bold;
    font-size: 12px;
    color: @theme-color-text-light;
  }
}