Tweaks for Bootstrap 4.6 when in forced-color mode, see https://github.com/twbs/bootstrap/issues/35941

forced-color.scss

// Tweaks to Bootstrap to better support forced-color accessability mode.
// https://github.com/twbs/bootstrap/issues/35941

@media (forced-colors) {

    navbar.fixed-top {
        border-bottom: 1px solid transparent;
    }

    input[type="submit"],
    input[type="button"],
    button {
        outline: 1px solid LinkText !important;
    }

    .btn {
        color: ButtonText !important;
        background-color: ButtonFace !important;
    }
    .btn.btn-link {
        color: LinkText;
        background-color: Canvas;
    }

    .badge,
    .label {
        color: CanvasText;
        background-color: Canvas;
        outline:  1px solid CanvasText !important;
    }

    .progress {
        border: 1px solid Graytext;
    }
    .progress-bar {
        color: HighlightText;
        background-color: Highlight !important;
    }

    form-control::placeholder,
    .text-muted {
        color: GrayText !important;
    }

    .custom-control.custom-radio,
    .custom-control.custom-checkbox {
        // Remove space left for custom overlap
        margin-left: 0;
    }

    .custom-control-label::before,
    .custom-control-label::after {
        // Remove custom control overlay.
        display: none;
    }
    .custom-control-input {
        // Restore standard control visibility.
        position: relative;
        z-index: inherit;
        opacity: 1;
    }
}