.with-container-query-support {
    #message-lists-container {
        container: message-lists / inline-size;
    }
}

.message_row {
    display: grid;
    /* Prevent the messagebox column from overflowing the 1fr
       space allotted by specifying `minmax(0,1fr)`, which
       sets 0 as the minimum size, not the grid default of
       `auto`. */
    grid-template: auto auto / 2px minmax(0, 1fr);
    grid-template-areas:
        "date_unread_marker    date_row  "
        "message_unread_marker messagebox";

    border-left: 1px solid var(--color-message-list-border);
    border-right: 1px solid var(--color-message-list-border);
    background-color: var(--color-background-stream-message-content);

    &.private-message {
        background-color: var(--color-background-private-message-content);

        .data-container::after {
            background: linear-gradient(
                0deg,
                var(--color-background-private-message-content),
                transparent 100%
            );
        }
    }

    &.direct_mention {
        background-color: var(--color-background-direct-mention);

        .message_embed .data-container::after {
            background: linear-gradient(
                0deg,
                var(--color-background-direct-mention),
                transparent 100%
            );
        }
    }

    &.group_mention {
        background-color: var(--color-background-group-mention);

        .message_embed .data-container::after {
            background: linear-gradient(
                0deg,
                var(--color-background-group-mention),
                transparent 100%
            );
        }
    }

    &.sender_info_hovered {
        .sender_name {
            cursor: pointer;
            /* TODO: Refactor the teetering nested classes
               above so that !important can be removed. */
            color: var(--color-text-sender-name-hover) !important;
        }

        .message-avatar {
            cursor: pointer;
        }
    }
}

.messagebox {
    grid-area: messagebox;
    overflow-wrap: break-word;
    border: none;
    /* The left padding value accounts for a 2px
      unread marker, ensuring a uniform 5px of
      padding on either side of the message box. */
    padding: 0 5px 0 3px;

    &:hover .message_controls {
        > .message_control_button {
            opacity: 1;
            visibility: visible;
        }
    }
}

.messagebox-content {
    display: grid;
    align-content: baseline;
    padding-left: 10px;
    /* Prevent the message column from overflowing the 1fr
       space allotted by specifying `minmax(0,1fr)`, which
       sets 0 as the minimum size, not the grid default of
       `auto`.

        The calculated `--message-box-timestamp-column-width`
        should match `max-content` exactly, but `max-content`
        ensures the timestamp will always have enough space
        in the column. */
    grid-template:
        minmax(var(--message-box-sender-line-height), auto) repeat(3, auto) /
        var(--message-box-avatar-column-width) minmax(0, 1fr) max-content
        8px minmax(var(--message-box-timestamp-column-width), max-content);
    /* Named grid areas provide flexibility for positioning grid items
       reliably, even if the row or column definitions of the grid change. */
    grid-template-areas:
        "edited message   controls . time"
        ".      message   .        . .   "
        ".      more      .        . .   "
        ".      reactions .        . .   ";

    &.content_edit_mode {
        cursor: default;
        /* Set the controls area to 0 to give more space
           to the edit/source view area. */
        grid-template-columns:
            var(--message-box-avatar-column-width) minmax(0, 1fr)
            0 8px minmax(
                var(--message-box-timestamp-column-width),
                max-content
            );
    }

    .message_edit_notice {
        grid-area: edited;
        align-self: center;
    }

    .edit-notifications {
        grid-area: edited;
        align-self: center;
    }

    .slow-send-spinner {
        display: none;
        place-self: center end;
        position: unset;
        margin-top: 1px;
        margin-right: 10px;
        text-align: end;
        grid-area: time;
    }

    .message_content:not(.status-message) {
        grid-area: message;
        padding: var(--message-box-markdown-aligned-vertical-space) 0 0;
        color: var(--color-text-message-default);
        /* We explicitly set line-height here so that
           the message area is not beholden to the legacy
           `max()` declaration on `body`. */
        line-height: var(--base-line-height-unitless);
        min-height: 17px;
        display: block;
        position: relative;
        overflow: hidden;

        /* For the sake of paragraphs and lists that include
           links, we adjust the vertical space here to keep
           it uniform. */
        &:has(> p:first-child, > ol:first-child, > ul:first-child) {
            padding-top: calc(
                var(--message-box-markdown-aligned-vertical-space) -
                    var(--message-box-link-focus-ring-block-padding)
            );
        }

        &:empty {
            display: none;
        }

        &.condensed {
            max-height: 8.5em;
            min-height: 0;
            overflow: hidden;
            mask-image: linear-gradient(
                to top,
                hsl(0deg 0% 100% / 0%) 0%,
                hsl(0deg 0% 100%) 60px
            );
            mask-size: cover;
        }

        &.collapsed {
            padding: 0;
            max-height: 0;
            min-height: 0;
            overflow: hidden;
        }
    }

    .message_reactions {
        grid-area: reactions;
        display: flex;
        /* Allow reactions to wrap in mobile viewports */
        flex-wrap: wrap;
        /* Keep reactions aligned to start (top), so that the
           margin on the reaction button doesn't appear to
           stretch the reactions taller. */
        align-items: flex-start;
        /* Control reaction spacing with a gap */
        gap: 4px;
    }

    .message_edit {
        grid-area: message;
        /* Align self to start, rather than baseline, so the baseline
          is preserved from the message itself--keeping the time,
          edit message, and controls at the same vertical alignment. */
        align-self: start;
        margin-top: var(--message-box-vertical-margin);
    }

    .message_length_controller {
        grid-area: more;
    }

    .collapsed ~ .message_length_controller {
        /* When content is collapsed, the length controller
           should occupy the space ordinarily assigned to
           the message. */
        grid-area: message;
        /* However, don't let the SHOW MORE button participate
           in the baseline group. */
        align-self: start;

        .message_length_toggle {
            /* Ensure that a collapsed message maintains the
               same space around the toggle button as any other
               message-row content. */
            margin: 4px 0;
        }
    }

    .message_length_toggle {
        width: 100%;
        height: 1.714em; /* 24px / 14px em */
        margin-bottom: var(--message-box-markdown-aligned-vertical-space);
        color: var(--color-text-show-more-less-button);
        background-color: var(--color-show-more-less-button-background);
        border-radius: 4px;
        border: none;
        outline: none;
        font-variant: all-small-caps;

        &:hover {
            background-color: var(
                --color-show-more-less-button-background-hover
            );
        }

        &:active {
            background-color: var(
                --color-show-more-less-button-background-active
            );
            scale: 0.98;
        }
    }

    &.content_edit_mode .message_length_controller {
        /* If entering edit mode on a collapsed message,
           just hide the controller area. This preserves
           the collapsed state of the message, which need
           not be touched. We just need to hide the button.
           This works for condensed messages, too. */
        display: none;
    }
}

.messagebox-includes-sender {
    .messagebox-content {
        grid-template-areas:
            "avatar sender    controls . time"
            "avatar message   .        . .   "
            ".      more      .        . .   "
            ".      reactions .        . .   ";

        .message_edit {
            /* No top margin when there's a sender row */
            margin-top: 0;
        }

        &.is-me-message {
            grid-template-areas:
                ".      .         .        . .   "
                "avatar sender    controls . time"
                "avatar sender    .        . .   "
                ".      more      .        . .   "
                ".      reactions .        . .   ";
            grid-template-rows:
                var(--message-box-vertical-margin) var(
                    --message-box-avatar-height
                )
                minmax(0, auto) repeat(3, auto);
            /* We align items to the baseline on me messages,
               and unset the align-content property. */
            align-items: baseline;
            align-content: unset;

            .message-avatar {
                /* Set the line-height to match the height of the avatar image
                   to center me-messages within the baseline group. */
                line-height: var(--message-box-avatar-height);
                align-self: baseline;
                /* Because the avatar may be the tallest element in a
                   single-line me message, this margin preserves the
                   overall height of the message box. */
                margin-bottom: var(--message-box-vertical-margin);

                .inline_profile_picture {
                    /* We adjust the vertical space in me messages via
                       the grid definition above. */
                    margin-top: 0;
                }
            }

            .message_controls {
                /* Because the controls height is smaller than the
                   available grid row height on me-messages, we
                   align to center here. */
                align-self: center;
            }

            .message_edit_notice {
                /* Unset the margin on a typical sender line. */
                margin-left: 0;
            }

            .message_sender {
                /* Don't display message sender as flexbox for me-messages. */
                display: block;
                /* Set the same line-height as on message content for
                   me-messages. */
                line-height: var(--base-line-height-unitless);
                /* Ensure the same spacing below messages as for any other
                   paragraph. */
                padding-bottom: var(
                    --message-box-markdown-aligned-vertical-space
                );
                /* Don't allow an ellipsis to display on me-messages. This is
                   an edge case that can happen with elements such as the
                   inline audio player. */
                overflow: visible;

                /* Display message components inline, with wrapping white-space,
                   so the sender name and message display as a continuous line
                   of wrapping text. */
                .sender_name {
                    white-space: normal;
                    display: inline;
                }

                .sender_name_text {
                    max-width: 100%;
                }
            }

            &.content_edit_mode {
                .message_sender {
                    /* Keep the me-message participating in the baseline */
                    visibility: hidden;
                }

                .message_edit {
                    /* Use the sender grid area for the me-message edit/view-source box */
                    grid-area: sender;
                    margin-top: var(--message-box-vertical-margin);
                }
            }
        }

        .message-avatar {
            grid-area: avatar;
            /* The picture should not participate in the baseline group. */
            align-self: start;

            .inline_profile_picture {
                /* Setting the margin inside this element prevents
                   unwanted shifts in the placement of especially
                   sender-line elements on the .messagebox-content
                   grid. */
                margin-top: var(--message-box-vertical-margin);
            }
        }

        .status-message {
            font-weight: normal;
        }

        .message_content {
            /* Pull message content up closer to sender to
               let the text baseline sit adjacent the bottom
               of the avatar. We also need to account for the
               padding atop .message_content. */
            margin-top: calc(
                (
                        var(--message-box-markdown-aligned-vertical-space) *
                            0.5 * -1
                    ) -
                    var(--message-box-markdown-aligned-vertical-space)
            );
            grid-area: message;
        }

        .message_edit_notice {
            /* When the edit notice is inline, as on edited me-messages,
              the inline-block and accompanying vertical-align styles will
              apply */
            display: inline-block;
            vertical-align: baseline;
            /* A bit of margin here helps these not look associated with the name. */
            margin-left: 4px;
            /* Unset the padding, align-self used on edited notices under the avatar. */
            padding-right: 0;
            align-self: unset;

            &.hide {
                display: none;
            }
        }

        .message_sender {
            overflow: hidden;
            text-overflow: ellipsis;
            grid-area: sender;
            display: flex;
            /* A generous line-height on the sender name is necessary
               for internationalization and non-Western Latin character
               sets. */
            line-height: var(--message-box-sender-line-height);
            /* Ensure flexed sender info (name, status emoji, inline EDITED)
               forms a baseline group, which will participate with the
               message-box grid's baseline group, too. */
            align-items: baseline;

            .zulip-icon.zulip-icon-bot {
                align-self: center;
                margin-left: 5px;
                /* The bot icon is center-aligned but appears
                slightly misaligned with the bot name text due
                to its shape. Adding a negative top margin ensures
                it's proper alignment. */
                margin-top: -0.12em;
            }

            .sender_name {
                display: inline-flex;
                font-weight: 700;
                color: var(--color-text-sender-name);
                column-gap: 3px;
                overflow: hidden;
                text-overflow: ellipsis;
                white-space: nowrap;
                outline: none;
                align-self: baseline;

                .sender_name_text {
                    overflow: hidden;
                    white-space: nowrap;
                    display: inline-flex;

                    .user-name {
                        overflow: hidden;
                        text-overflow: ellipsis;
                    }
                }
            }
        }
    }

    .collapsed ~ .message_length_controller .message_length_toggle {
        /* Collapse top margin to avoid extra space
           between the button and sender line. */
        margin-top: 0;
    }
}

.message_controls {
    grid-area: controls;
    /* Let the controls occupy the entire height
       of the row; inner flexboxes handle the
       centering of the icons. */
    align-self: stretch;
    /* Controls flex to the height of the top
       row of the message box, and center
       themselves within it. */
    display: flex;
    align-items: center;
    /* Ensure square icons for better centering. */
    line-height: 1;

    @container message-lists (width < $cq_sm_min) {
        /* This is intended to target the first message_controls child
           when there are 3 displayed. */
        .message_control_button:nth-last-child(3) {
            display: none;
        }
    }

    /* Media-query fallback. Note that because we're treating
       #message-lists-container as its own container, we can
       express a much simpler query there. The more complex
       conditions are necessary only for media queries. */
    @media (width < $sm_min), ((width >= $md_min) and (width < $mc_min)) {
        .without-container-query-support {
            /* This is intended to target the first message_controls child
            when there are 3 displayed. */
            .message_control_button:nth-last-child(3) {
                display: none;
            }
        }
    }

    /* This is a bit tricky; we need to reserve space for the message
       controls even when the message isn't hovered, so that hover
       doesn't disturb the layout.  Usually that would be just
       visibility: hidden, but that cannot be animated, so we set
       opacity as well, which can be animated. */
    .message_control_button {
        opacity: 0;
        visibility: hidden;
        transition: 0.2s ease;
        transition-property: opacity, visibility;
        /* Allow buttons to grow to fill the available space,
           in concord with the column calculated for the
           .messagebox-content grid. */
        flex: 1 0 0;
        /* Set the height to 100% to effectively flex open
           on the vertical axis. */
        height: 100%;
        /* Control buttons are their own flex containers,
           to more gracefully center the icons. */
        display: flex;
        place-items: center center;
        color: var(--color-message-action-visible);

        .emoji-message-control-button-container {
            /* This button has an extra div for Tippy purposes,
               so it becomes its own flex container. */
            display: flex;
        }

        & .message-controls-icon {
            cursor: pointer;
            /* The icon body is 16px square at 16px/1em; the clickable
               area for the icon is 26px wide by 25px tall, so these
               values ensure a 26px x 25px clickable area for the icon. */
            /* 2.5px at 16px/1em; 3px at 16px/1em */
            padding: 0.1563em 0.1875em;

            &::before {
                /* We specify block display so the
                   scaling transform below works as
                   expected. */
                display: block;
            }

            &:active::before {
                transform: scale(0.92);
                transform-origin: center;
                outline: 0;
            }

            &:focus {
                /* Remove the outline but do not color on focus;
                   focus-visible is more appropriate for the color
                   changes, as it only applies color when focus
                   is achieved from a keyboard or other pointerless
                   device. */
                outline: 0;
            }

            &:hover,
            &:focus-visible {
                outline: 0;
                color: var(--color-message-action-interactive);
            }

            /* Separate hover colors for stars */
            &.star:hover,
            &.star:focus-visible {
                color: var(--color-message-star-action);
            }
        }
    }

    /* Tooltips should not follow the width restrictions of their parent element. */
    [data-tippy-root] {
        width: max-content;
        overflow-wrap: unset;
    }

    .edit_content {
        width: var(--message-box-icon-width);

        .move_message_button,
        .edit_content_button {
            display: none;
        }

        &.can-edit-content {
            .edit_content_button {
                display: inline;
            }
        }

        &.can-move-message {
            .move_message_button {
                display: inline;
            }
        }
    }

    .failed_message_action {
        color: var(--color-failed-message-send-icon);
        font-weight: bold;
        padding: 1px;
        opacity: 1;
        visibility: visible;

        .rotating {
            animation: rotate 1s infinite linear;
        }
    }

    .star_container {
        &:not(.empty-star) {
            /* Color, opacity, and visibility, as though the message is hovered. */
            color: var(--color-message-star-action);
            opacity: 1;
            visibility: visible !important;
        }
    }
}

.unread_marker {
    margin-left: var(--unread-marker-left);
    opacity: 0;
    transition: opacity 0.3s ease-out;

    &.slow_fade {
        transition: opacity 2s ease-out;
    }

    &.fast_fade {
        transition: opacity 0.3s ease-out;
    }

    &.date_unread_marker {
        grid-area: date_unread_marker;

        .unread-marker-fill {
            border-radius: 0 !important;
            height: 100% !important;
        }
    }

    &.message_unread_marker {
        grid-area: message_unread_marker;
    }
}

.unread-marker-fill {
    height: 100%;
    width: 2px;
    background: linear-gradient(
        90deg,
        var(--color-unread-marker) 30%,
        hsl(217deg 64% 59% / 0%)
    );
}

.unread .unread_marker {
    transition: opacity 0.3s ease-out;
    opacity: 1;
}

.message-time {
    justify-self: end;
    padding-right: 5px;
    /* Maintain first-line baseline regardless of
       what happens in the message-content area (e.g., a
       collapsed message, or source/edit view). This
       line-height also keeps EDITED/MOVED messages
       in place, care of their baseline-group participation
       within the grid. */
    line-height: var(--message-box-sender-line-height);
    grid-area: time;
    display: block;
    /* 13px at 14px/1em */
    font-size: 0.9286em;
    font-weight: 350;
    text-align: end;
    opacity: 0.8;
    color: var(--color-text-default);
    letter-spacing: 0.02em;
    /* Disable blue link styling for the message timestamp link. */
    &:hover {
        text-decoration: none;
        color: var(--color-message-action-interactive);
    }

    &.notvisible {
        /* This happens when message failed to send. We don't want to
           display time but still want it to occupy space. */
        width: 45px !important;
        position: unset !important;
    }
}

/* Message-editing styles */
.message-edit-buttons-and-timer {
    margin-top: 5px;
    display: flex;
    gap: 5px;
    /* Allow items to occupy full height.
       This is especially important for
       buttons that are flex items. */
    align-items: stretch;
}

.message-actions-button {
    box-sizing: border-box;
    align-self: stretch;
    /* Display the actions buttons as
       flex containers for positioning
       text and spinners. */
    display: flex;
    align-items: center;
    justify-content: center;
    /* 28px at 16px/1em, per Vlad's spec. */
    height: 1.75em;
    /* 65px at 16px/1em, which is the width of
       the Cancel button. */
    min-width: 4.0625em;
    padding: 0 10px;
    border-radius: 4px;
    border: 0;
    line-height: 1;

    &:focus {
        outline: none;
    }

    &:focus-visible {
        outline: 2px solid var(--color-outline-focus);
    }
}

.message_edit_save {
    /* Match Save button's basic colors to
       the compose box Send button. */
    color: var(--color-compose-send-button-icon-color);
    background-color: var(--color-compose-send-button-background);

    &:hover {
        background-color: var(
            --color-compose-send-button-background-interactive
        );
    }

    &:disabled {
        /* Replicate disabled values, without any color shifts. */
        cursor: not-allowed;
        opacity: 0.5;
    }
}

.message_edit_cancel,
.message_edit_close {
    color: var(--color-exit-button-text);
    background: var(--color-exit-button-background);

    &:hover {
        background: var(--color-exit-button-background-interactive);
    }
}

.edit-content-container {
    border-radius: 4px;
    border: 1px solid var(--color-message-content-container-border);
    transition: border-color 0.2s ease;
    display: grid;
    grid-template-areas: "message-edit-content";

    &:has(.message_edit_content:focus) {
        border-color: var(--color-message-content-container-border-focus);
    }

    .message-edit-textbox {
        /* Setting `position:relative` on this container ensures that .copy-button
           (a possible immediate child with `position: absolute`) is positioned
           relative to this container instead of <html>. */
        position: relative;
        grid-area: message-edit-content;

        .textarea-over-limit {
            background-color: var(
                --color-compose-message-content-background-over-limit
            );
        }

        .textarea-approaching-limit {
            background-color: var(
                --color-compose-message-content-background-approaching-limit
            );
        }
    }
}

.message_edit_content {
    max-height: var(--max-message-edit-height);
    width: 100%;
    min-width: 206px;
    min-height: 52px;
    box-sizing: border-box;
    /* Setting resize as none hides the bottom right diagonal box
       (which even has a background color of its own!). */
    resize: none !important;
    color: var(--color-text-default);
    background-color: hsl(0deg 0% 100%);
    border-radius: 3px;
    vertical-align: middle;
    border: none;
    /* Match textarea padding to compose box and
       message-edit preview area. */
    padding: 5px 5px 0;
    margin: 0;

    box-shadow: none;

    &:focus {
        outline: 0;
    }

    &:read-only,
    &:disabled {
        cursor: not-allowed;
    }
}

/* The selector needs to be written this way to override the specificity
of the base style defined for a read-only textarea in dark mode. */
.message_edit_form .edit-controls textarea.message_edit_content:read-only {
    opacity: 1;
}

.message-editing-animation {
    display: inline-flex;
    align-items: baseline;
    margin-left: 3px;
    width: 40px;
    height: 5px;

    /* Avoid this animation element blocking clicks on .edit-notifications
       to display the message's edit history. */
    pointer-events: none;

    .y-animated-dot {
        width: 4px;
        height: 4px;
        background-color: hsl(0deg 0% 53%);
        border-radius: 50%;
        margin-left: 3px;
        opacity: 0;

        &:nth-child(1) {
            animation: typing 1s infinite 0.2s;
        }

        &:nth-child(2) {
            animation: typing 1s infinite 0.4s;
        }

        &:nth-child(3) {
            animation: typing 1s infinite 0.6s;
        }
    }
}

@keyframes typing {
    0% {
        opacity: 0;
        transform: translateY(0);
    }

    50% {
        opacity: 1;
        transform: translateY(-3px);
    }

    100% {
        opacity: 0;
        transform: translateY(0);
    }
}

.message_edit_countdown_timer {
    text-align: right;
    display: inline;
    color: hsl(0deg 0% 63%);

    &.expired {
        color: hsl(4deg 58% 33%);
    }
}

.message-edit-timer {
    display: none;
    /* Center vertically relative to
       buttons. */
    align-self: center;
    /* Use flexbox to position to far right of
       the Save and Cancel buttons. */
    margin-left: auto;
}

.message-edit-feature-group {
    border-radius: 0 0 3px 3px;
    background-color: var(--color-message-formatting-controls-container);
    /* margin on either side to let the border of
       .edit-content-container show through. */
    margin: 0 1px;
}

.message_edit_save .loader {
    display: none;
    /* 28px at 16px/1em */
    height: 1.75em;
    width: 1.75em;
    grid-area: button-display;
    justify-self: center;
    z-index: 1;
}

.message_edit_save:has(.showing-button-spinner) {
    /* We want to maintain the width of the Save button
       in an i18n friendly way; this quick grid ensures
       that the width of the text holds the button open,
       while the styles above ensure the spinner's
       centering. */
    display: grid;
    grid-template: "button-display";
}

.showing-button-spinner {
    visibility: hidden;
    grid-area: button-display;
    z-index: 0;
}

.edit-controls {
    .button-wrapper {
        cursor: not-allowed;
    }
}

.message-edit-button-disabled {
    pointer-events: none;
}

/* Reduce some of the heavy padding from Bootstrap. */
.message_edit_form {
    margin-bottom: 10px;
    cursor: default;

    .edit-form {
        /* Override Bootstrap. */
        margin-bottom: 0;
    }

    .edit-controls {
        margin-left: 0;
        margin-top: 0;
    }

    .preview_message_area {
        max-height: var(--max-message-edit-height);
        grid-area: message-edit-content;
    }
}

.message_edit_notice {
    /* 10px at 14px/1em */
    font-size: 0.7143em;
    opacity: 0.5;
    user-select: none;
    white-space: nowrap;
    overflow-x: hidden;
    overflow-x: clip;
    text-overflow: ellipsis;
    padding-right: 5.5px;
    cursor: pointer;
}

.fade-in-message {
    animation-name: fadeInMessage;
    animation-duration: 1s;
    animation-iteration-count: 1;

    .message_edit_notice {
        animation-name: fadeInEditNotice;
        animation-duration: 1s;
        animation-iteration-count: 1;
    }
}

.message_edit_notice_hover:hover {
    opacity: 1;
}

/* Locally echoed messages. */
.locally-echoed .message-time {
    opacity: 0;
    /* Don't show pointer when message-time doesn't have a link. */
    cursor: default;
}

/* Show the spinner only for messages that are still locally echoed. */
.locally-echoed .slow-send-spinner {
    display: unset !important;
    cursor: default;
}

/* Placehold the control buttons, unless there's a failure. */
.locally-echoed {
    .messagebox:hover
        .message_controls
        .message_control_button:not(.failed_message_action) {
        visibility: hidden;
    }
    /* The actual star icon is not added to the DOM when a
       message is locally echoed, so we set the equivalent
       width on its container. */
    .star_container {
        width: var(--message-box-icon-width);
    }
}

.recipient_row {
    /* See https://stackoverflow.com/questions/2717480/css-selector-for-first-element-with-class/8539107#8539107
       for details on how this works */
    .message_row.unread {
        .date_unread_marker {
            display: none;
        }
    }

    /* Select all but the first .message_row.unread,
       and remove the properties set from the previous rule. */
    .message_row.unread ~ .message_row.unread {
        .date_unread_marker {
            display: block;
        }
    }
}

.date_row {
    grid-area: date_row;

    & .timerender-content {
        display: block;
        overflow: hidden;
        text-transform: uppercase;
        font-size: calc(12em / 14);
        font-style: normal;
        font-weight: 600;
        line-height: 17px; /* identical to box height, or 131% */
        text-align: right;
        letter-spacing: 0.04em;
        color: var(--color-date);
        /* Right padding matches time in message row and date in recipient row. */
        padding: 8px 6px 8px 4px;

        &::before {
            width: 100%;
        }

        &::after {
            width: 6px;
            left: 0.25em;
            /* Align date with message time and recipient bar date. */
            margin-right: -1px;
        }
    }
}

.bookend {
    margin-top: 10px;
    background-color: transparent;
    padding-bottom: 10px;
    text-align: center;

    .stream-status {
        opacity: 0.6;

        & i {
            font-size: 0.7143em; /* 10px at 14px / em */
            /* TODO: Don't use relative positioning here. */
            position: relative;
            top: 0.1em; /* 1px at 10px / em */
            margin-left: 0.2em; /* 2px at 10px / em */
        }

        .zulip-icon.zulip-icon-lock {
            font-size: 0.8571em; /* 12px at 14px / em */
            top: 0.0833em; /* 1px at 12px / em */
            margin-left: 0.1667em; /* 2px at 12px / em */
        }
    }
}

.bookend-label {
    font-size: 1em;
    display: block;
    padding: 4px;
    overflow: hidden;

    &::before,
    &::after {
        width: 50%;
    }

    &::after {
        left: 0.25em;
        margin-right: -50%;
    }
}

/* Only show links on the trailing bookend. */
.bookend-channel-settings-link {
    display: none;
}

.trailing_bookend .bookend-channel-settings-link {
    display: inline;
}

.bookend-label::before,
.bookend-label::after,
.date_row .timerender-content::before,
.date_row .timerender-content::after {
    display: inline-block;
    position: relative;
    content: " ";
    vertical-align: middle;
    height: 0;
    border-bottom: 1px solid var(--color-border-message-group-spacer-line);
}

.bookend-label::before,
.date_row .timerender-content::before {
    right: 0.25em;
    margin-left: -50%;
}