@use "../../variables";
// We want overlays to always appear over user content, so set a baseline
// very high z-index for the overlay container, which is where we create the new
// stacking context for all overlays.
$cdk-z-index-overlay-container: 1000;
$cdk-z-index-overlay: 1000;
$cdk-z-index-overlay-backdrop: 1000;

// Background color for all of the backdrops
$cdk-overlay-dark-backdrop-background: rgba(0, 0, 0, 0.55) !default;

// Default backdrop animation is based on the Material Design swift-ease-out.
$backdrop-animation-duration: 400ms !default;
$backdrop-animation-timing-function: cubic-bezier(0.25, 0.8, 0.25, 1) !default;

@mixin cdk-overlay() {
    .cdk-overlay-container,
    .cdk-global-overlay-wrapper {
        // Disable events from being captured on the overlay container.
        pointer-events: none;

        // The container should be the size of the viewport.
        top: 0;
        left: 0;
        height: 100%;
        width: 100%;

        // 弹出模态框时外部的滚动条可以滚动
        // overflow-y: auto;
        // justify-content: center;
        // align-items: baseline;
    }

    // The overlay-container is an invisible element which contains all individual overlays.
    .cdk-overlay-container {
        position: fixed;
        z-index: $cdk-z-index-overlay-container;

        &:empty {
            // Hide the element when it doesn't have any child nodes. This doesn't
            // include overlays that have been detached, rather than disposed.
            display: none;
        }
    }

    // We use an extra wrapper element in order to use make the overlay itself a flex item.
    // This makes centering the overlay easy without running into the subpixel rendering
    // problems tied to using `transform` and without interfering with the other position
    // strategies.
    .cdk-global-overlay-wrapper {
        display: flex;
        position: absolute;
        z-index: $cdk-z-index-overlay;
    }

    // A single overlay pane.
    .cdk-overlay-pane {
        // Note: it's important for this one to start off `absolute`,
        // in order for us to be able to measure it correctly.
        position: absolute;
        pointer-events: auto;
        box-sizing: content-box;
        z-index: $cdk-z-index-overlay;

        // For connected-position overlays, we set `display: flex` in
        // order to force `max-width` and `max-height` to take effect.
        display: flex;
        max-width: 100%;
        max-height: 100%;
    }

    .cdk-overlay-backdrop {
        // TODO(jelbourn): reuse sidenav fullscreen mixin.
        position: absolute;
        top: variables.$zero;
        bottom: variables.$zero;
        left: variables.$zero;
        right: variables.$zero;

        z-index: $cdk-z-index-overlay-backdrop;
        pointer-events: auto;
        -webkit-tap-highlight-color: transparent;
        transition: opacity $backdrop-animation-duration $backdrop-animation-timing-function;
        opacity: 0;

        &.cdk-overlay-backdrop-showing {
            opacity: 1;

            // In high contrast mode the rgba background will become solid so we need to fall back
            // to making it opaque using `opacity`. Note that we can't use the `cdk-high-contrast`
            // mixin, because we can't normalize the import path to the _a11y.scss both for the
            // source and when this file is distributed. See #10908.
            @media screen and (-ms-high-contrast: active) {
                opacity: 0.6;
            }
        }
    }

    .cdk-overlay-dark-backdrop {
        background: $cdk-overlay-dark-backdrop-background;
    }

    .cdk-overlay-transparent-backdrop {
        // Note: as of Firefox 57, having the backdrop be `background: none` will prevent it from
        // capturing the user's mouse scroll events. Since we also can't use something like
        // `rgba(0, 0, 0, 0)`, we work around the inconsistency by not setting the background at
        // all and using `opacity` to make the element transparent.
        &,
        &.cdk-overlay-backdrop-showing {
            opacity: 0;
        }
    }

    // Overlay parent element used with the connected position strategy. Used to constrain the
    // overlay element's size to fit within the viewport.
    .cdk-overlay-connected-position-bounding-box {
        position: absolute;
        z-index: $cdk-z-index-overlay;

        // We use `display: flex` on this element exclusively for centering connected overlays.
        // When *not* centering, a top/left/bottom/right will be set which overrides the normal
        // flex layout.
        display: flex;

        // We use the `column` direction here to avoid some flexbox issues in Edge
        // when using the "grow after open" options.
        flex-direction: column;

        // Add some dimensions so the element has an `innerText` which some people depend on in tests.
        min-width: 1px;
        min-height: 1px;
    }

    // Used when disabling global scrolling.
    .cdk-global-scrollblock {
        position: fixed;

        // Necessary for the content not to lose its width. Note that we're using 100%, instead of
        // 100vw, because 100vw includes the width plus the scrollbar, whereas 100% is the width
        // that the element had before we made it `fixed`.
        width: 100%;

        // Note: this will always add a scrollbar to whatever element it is on, which can
        // potentially result in double scrollbars. It shouldn't be an issue, because we won't
        // block scrolling on a page that doesn't have a scrollbar in the first place.
        overflow-y: scroll;
    }
}
