/*
Copyright 2015, 2016 OpenMarket Ltd
Copyright 2020-2021 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

$left-gutter: 64px;

.mx_EventTile {
    --EventTile_content-margin-inline-end: 34px; // TODO: Use a spacing variable
    --EventTile_group_line-spacing-block-start: 1px;
    --EventTile_group_line-spacing-block-end: 3px;
    --EventTile_group_line-spacing-inline-start: $left-gutter;
    --EventTile_group_line-line-height: $font-22px;
    --EventTile_ThreadSummary-line-height: calc(2 * $font-12px);

    flex-shrink: 0;

    .mx_EventTile_avatar {
        cursor: pointer;
        user-select: none;
    }

    .mx_EventTile_body {
        overflow-y: hidden;
    }

    .mx_EventTile_receiptSent,
    .mx_EventTile_receiptSending {
        position: relative;
        display: inline-block;
        width: 16px;
        height: 16px;

        &::before {
            background-color: $tertiary-content;
            mask-repeat: no-repeat;
            mask-position: center;
            mask-size: 16px;
            width: 16px;
            height: 16px;
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
        }
    }

    .mx_EventTile_receiptSent::before {
        mask-image: url('$(res)/img/element-icons/circle-sent.svg');
    }

    .mx_EventTile_receiptSending::before {
        mask-image: url('$(res)/img/element-icons/circle-sending.svg');
    }

    .mx_EventTile_content {
        &.mx_EditMessageComposer {
            // Make sure the formatting bar is visible
            overflow: visible;
        }
    }

    .mx_EventTile_searchHighlight {
        background-color: $accent;
        color: $accent-fg-color;
        border-radius: 5px;
        padding-inline: 2px;
        cursor: pointer;

        a {
            background-color: $accent;
            color: $accent-fg-color;
        }
    }

    .mx_EventTileBubble {
        margin-block: var(--EventTileBubble_margin-block);
    }

    .mx_MImageBody {
        .mx_MImageBody_thumbnail_container {
            display: flex;
            align-items: center; // on every layout
        }
    }

    .mx_DisambiguatedProfile {
        color: $primary-content;
        font-size: $font-14px;
        display: inline-block;
        padding-bottom: 0px;
        padding-top: 0px;
    }

    .mx_ReactionsRow {
        display: flex;
        flex-flow: wrap;
        align-items: center;
        gap: $spacing-4;
    }

    .mx_ReplyChain--expanded {
        .mx_EventTile_body {
            display: block;
            overflow-y: scroll;
        }

        .mx_EventTile_collapsedCodeBlock {
            // !important needed due to .mx_ReplyTile .mx_EventTile_content .mx_EventTile_pre_container > pre
            display: block !important;
        }
    }

    .mx_RoomView_searchResultsPanel & {
        &.mx_EventTile_contextual {
            opacity: 0.4;
        }
    }

    &.mx_EventTile_highlight,
    &.mx_EventTile_highlight .markdown-body {
        color: $alert;
    }

    &.mx_EventTile_bubbleContainer {
        display: grid;
        grid-template-columns: 1fr 100px;

        .mx_EventTile_line {
            margin-right: 0;
            grid-column: 1 / 3;
            padding: 0 !important; // override default padding of mx_EventTile_line so that we can be centered
        }

        .mx_EventTile_msgOption {
            grid-column: 2;
        }

        &:hover {
            .mx_EventTile_line {
                // To avoid bubble events being highlighted
                background-color: inherit !important;
            }
        }
    }

    &.mx_EventTile_isEditing .mx_MessageTimestamp {
        visibility: hidden;
    }

    &[data-layout="irc"],
    &[data-layout="group"] {
        // TODO: adjust the values for IRC layout
        --EventTile-box-shadow-offset-x: calc(50px + $selected-message-border-width);
        --EventTile-box-shadow-spread-radius: -50px;
        .mx_EventTile_e2eIcon {
            position: absolute;
        }

        .mx_MImageBody {
            .mx_MImageBody_thumbnail_container {
                justify-content: flex-start;
                min-height: $font-44px;
                min-width: $font-44px;
            }
        }

        .mx_EventTile_line,
        .mx_EventTile_reply {
            position: relative;
            border-radius: 8px;
        }

        .mx_EventTile_reply {
            margin-right: 10px;
        }

        .mx_EventTile_msgOption {
            float: right;
            text-align: right;
            position: relative;
            width: 90px;

            /* Hack to stop the height of this pushing the messages apart.
               Replaces margin-top: -6px. This interacts better with a read
               marker being in between. Content overflows. */
            height: 1px;

            a {
                text-decoration: none;
            }
        }

        &.mx_EventTile_highlight,
        &.mx_EventTile_highlight .markdown-body {
            .mx_EventTile_line {
                background-color: $event-highlight-bg-color;
            }
        }

        &.focus-visible:focus-within,
        &.mx_EventTile_actionBarFocused,
        &.mx_EventTile_isEditing,
        &.mx_EventTile_selected {
            .mx_EventTile_line {
                background-color: $event-selected-color;
            }
        }

        // this is used for the tile for the event which is selected via the URL.
        &.mx_EventTile_isEditing,
        &.mx_EventTile_selected {
            > .mx_EventTile_line {
                // TODO: ultimately we probably want some transition on here.
                box-shadow:
                    inset var(--EventTile-box-shadow-offset-x) 0 0
                    var(--EventTile-box-shadow-spread-radius) $accent;
            }
        }

        &.mx_EventTile_info {
            .mx_EventTile_e2eIcon {
                top: 0;
            }
        }

        &.mx_EventTile_continuation .mx_EventTile_line {
            clear: both;
        }

        &:hover {
            .mx_EventTile_line {
                background-color: $event-selected-color;
            }

            &.mx_EventTile_verified .mx_EventTile_line {
                box-shadow:
                    inset var(--EventTile-box-shadow-offset-x) 0 0
                    var(--EventTile-box-shadow-spread-radius) $e2e-verified-color;
            }

            &.mx_EventTile_unverified .mx_EventTile_line {
                box-shadow:
                    inset var(--EventTile-box-shadow-offset-x) 0 0
                    var(--EventTile-box-shadow-spread-radius) $e2e-unverified-color;
            }

            &.mx_EventTile_unknown .mx_EventTile_line {
                box-shadow:
                    inset var(--EventTile-box-shadow-offset-x) 0 0
                    var(--EventTile-box-shadow-spread-radius) $e2e-unknown-color;
            }
        }
    }

    &[data-layout="bubble"],
    &[data-layout="group"] {
        .mx_EventTileBubble {
            margin-inline: auto;
        }
    }

    &[data-layout="irc"] {
        --EventTile_irc_line_info-margin-inline-start: calc(var(--name-width) + 10px + var(--icon-width));

        .mx_EventTile_msgOption {
            .mx_ReadReceiptGroup {
                inset-block-start: -0.3rem; // ($irc-line-height - avatar height) / 2
            }
        }

        .mx_MessageTimestamp {
            text-align: right;
        }

        .mx_EventTileBubble {
            position: relative;
            left: var(--EventTile_irc_line_info-margin-inline-start);

            &.mx_cryptoEvent {
                left: unset;
            }
        }

        .mx_ReplyTile .mx_EventTileBubble {
            left: unset; // Cancel the value specified above for the tile inside ReplyTile
        }

        &.mx_EventTile_isEditing > .mx_EventTile_line {
            .mx_EditMessageComposer {
                // add space for the stroke on box-shadow
                padding-inline-start: calc($selected-message-border-width + var(--EditMessageComposer-padding-inline));
            }
        }

        &.mx_EventTile_info {
            .mx_EventTile_avatar {
                left: var(--EventTile_irc_line_info-margin-inline-start);
                top: 0;
                margin-right: var(--right-padding);
                padding-block: var(--EventTile_irc_line-padding-block);
            }

            .mx_EventTile_line {
                margin-inline-start: var(--EventTile_irc_line_info-margin-inline-start);
            }
        }
    }

    &[data-layout="group"] {
        .mx_EventTile_avatar {
            top: 14px;
            left: $spacing-8;
        }

        .mx_EventTile_line,
        .mx_EventTile_reply {
            padding-top: var(--EventTile_group_line-spacing-block-start);
            padding-bottom: var(--EventTile_group_line-spacing-block-end);
            padding-left: var(--EventTile_group_line-spacing-inline-start);
            line-height: var(--EventTile_group_line-line-height);
        }

        .mx_EventTile_e2eIcon {
            inset: 6px 0 0 44px;
        }

        .mx_EventTile_msgOption {
            margin-inline-end: 10px;

            .mx_ReadReceiptGroup {
                // This aligns the avatar with the last line of the
                // message. We want to move it one line up
                // See .mx_EventTile[data-layout=group] .mx_EventTile_line in _EventTile.scss
                inset-block-start: calc(-$font-22px - 3px);
            }
        }

        .mx_MessageTimestamp {
            position: absolute;
            left: 0;
            text-align: center;
        }

        .mx_ThreadSummary,
        .mx_ThreadSummary_icon {
            margin-left: $left-gutter;
        }

        .mx_ReactionsRow {
            margin: $spacing-4 64px;
        }

        > .mx_DisambiguatedProfile {
            line-height: $font-20px;
            margin-left: $left-gutter;
            max-width: calc(100% - $left-gutter);
        }

        > .mx_EventTile_avatar {
            position: absolute;
            z-index: 9;
        }

        .mx_RoomView_timeline_rr_enabled & {
            $inline-end-margin: 80px; // TODO: Use a spacing variable

            .mx_ThreadSummary,
            .mx_ThreadSummary_icon,
            .mx_EventTile_line {
                margin-right: $inline-end-margin;
                min-height: $font-14px;
            }

            .mx_ThreadSummary {
                // leave space on both left & right gutters
                max-width: min(calc(100% - $left-gutter - $inline-end-margin), 600px);
            }

            // on ELS we need the margin to allow interaction with the expand/collapse button
            // which is normally in the RR gutter
        }

        &.mx_EventTile_continuation {
            padding-top: 0px !important;
        }

        &.mx_EventTile_info {
            $spacing-block-start: 3px;
            $spacing-block-end: 2px;

            padding-top: 0;

            .mx_EventTile_avatar,
            .mx_EventTile_e2eIcon {
                margin: $spacing-block-start 0 $spacing-block-end;
            }

            .mx_EventTile_avatar {
                top: initial;
                inset-inline-start: $left-gutter;
                height: 14px;
            }

            .mx_EventTile_line {
                padding-block: $spacing-block-start $spacing-block-end;
                // 20px: avatar area
                padding-inline-start: calc(var(--EventTile_group_line-spacing-inline-start) + 20px);

                .mx_MessageTimestamp {
                    top: 0;
                }
            }
        }

        &:hover {
            &.mx_EventTile_verified.mx_EventTile_info .mx_EventTile_line,
            &.mx_EventTile_unverified.mx_EventTile_info .mx_EventTile_line,
            &.mx_EventTile_unknown.mx_EventTile_info .mx_EventTile_line {
                padding-inline-start: calc($left-gutter + 18px + $selected-message-border-width);
            }
        }
    }

    &[data-layout="bubble"] {
        .mx_EventTile_msgOption {
            .mx_ReadReceiptGroup {
                position: absolute;
                inset-block-start: auto;

                // as close to right gutter without clipping as possible
                inset-inline-end: calc(-1 * var(--ReadReceiptGroup_EventBubbleTile-spacing-end));

                // (EventTileLine.line-height - ReadReceiptGroup.height) / 2
                // this centers the ReadReceiptGroup if we’ve got a single line
                inset-block-end: calc(($font-18px - 24px) / 2);
            }
        }
        .mx_EventTileBubble {
            // Timestamps are inside the tile, so the width can be less constrained
            max-width: 600px;
        }

        &.mx_EventTile_continuation {
            margin-top: 2px;
        }
    }
}

.mx_EventTile:not([data-layout="bubble"]) {
    max-width: 100%;
    clear: both;
    padding-top: 18px;
    font-size: $font-14px;
    position: relative;

    &.mx_EventTile_selected.mx_EventTile_info .mx_EventTile_line {
        padding-left: calc($left-gutter + 18px);
    }
}

.mx_GenericEventListSummary {
    &[data-layout="irc"],
    &[data-layout="group"] {
        .mx_EventTile_line .mx_RedactedBody {
            line-height: 1; // remove spacing between lines
        }
    }

    &[data-layout="irc"] {
        .mx_EventTile_line .mx_RedactedBody {
            padding-left: 24px; // 25px - 1px

            &::before {
                left: var(--right-padding);
            }
        }

        // Apply only collapsed events block
        > .mx_EventTile_line {
            // 15 px of padding
            /* stylelint-disable-next-line declaration-colon-space-after */
            padding-left:
                calc(var(--name-width) + var(--icon-width) + $MessageTimestamp_width + 3 * var(--right-padding));
        }
    }

    &[data-layout="group"] {
        .mx_EventTile_line {
            padding-left: $left-gutter;
        }

        .mx_GenericEventListSummary_unstyledList > .mx_EventTile_info .mx_EventTile_avatar ~ .mx_EventTile_line {
            padding-left: calc($left-gutter + 20px); // override padding-left $left-gutter
        }
    }
}

.mx_EventTile_content {
    /*
    all the overflow-y: hidden; are to trap Zalgos -
    but they introduce an implicit overflow-x: auto.
    so make that explicitly hidden too to avoid random
    horizontal scrollbars occasionally appearing, like in
    https://github.com/vector-im/vector-web/issues/1154
    */
    overflow-y: hidden;
    overflow-x: hidden;
    margin-right: var(--EventTile_content-margin-inline-end);

    .mx_EventTile_edited,
    .mx_EventTile_pendingModeration {
        user-select: none;
        font-size: $font-12px;
        color: $roomtopic-color;
        display: inline-block;
        margin-left: 9px;
    }

    .mx_EventTile_edited {
        cursor: pointer;
    }

    .markdown-body {
        font-family: inherit !important;
        white-space: normal !important;
        line-height: inherit !important;
        color: inherit; // inherit the colour from the dark or light theme by default (but not for code blocks)
        font-size: $font-14px;

        pre,
        code {
            font-family: $monospace-font-family !important;
            background-color: $codeblock-background-color;
        }

        code {
            white-space: pre-wrap; // don't collapse spaces in inline code blocks
        }

        pre {
            // have to use overlay rather than auto otherwise Linux and Windows
            // Chrome gets very confused about vertical spacing:
            // https://github.com/vector-im/vector-web/issues/754
            overflow-x: overlay;
            overflow-y: visible;

            &::-webkit-scrollbar-corner {
                background: transparent;
            }

            code {
                white-space: pre; // we want code blocks to be scrollable and not wrap

                > * {
                    display: inline;
                }
            }
        }

        h1,
        h2,
        h3,
        h4,
        h5,
        h6 {
            font-family: inherit !important;
            color: inherit;
        }

        /* Make h1 and h2 the same size as h3. */
        h1,
        h2 {
            font-size: 1.5em;
            border-bottom: none !important; // override GFM
        }

        a {
            color: $accent-alt;
        }

        blockquote {
            border-left: 2px solid $blockquote-bar-color;
            border-radius: 2px;
            padding: 0 10px;
        }

        /*
        // actually, removing the Italic TTF provides
        // better results seemingly

        // compensate for Nunito italics being terrible
        // https://github.com/google/fonts/issues/1726
        em {
            transform: skewX(-14deg);
            display: inline-block;
        }
        */
    }
}

/* Spoiler stuff */
.mx_EventTile_spoiler {
    cursor: pointer;

    .mx_EventTile_spoiler_reason {
        color: $event-timestamp-color;
        font-size: $font-11px;
    }

    .mx_EventTile_spoiler_content {
        filter: blur(5px) saturate(0.1) sepia(1);
        transition-duration: 0.5s;
    }

    &.visible > .mx_EventTile_spoiler_content {
        filter: none;
    }
}

.mx_EventTile_bigEmoji {
    font-size: 48px;
    line-height: 57px;

    .mx_Emoji {
        font-size: inherit !important;
    }
}

.mx_EventTile_e2eIcon {
    position: relative;
    width: 14px;
    height: 14px;
    display: block;
    background-repeat: no-repeat;
    background-size: contain;

    &::before,
    &::after {
        content: "";
        display: block;
        position: absolute;
        top: 0;
        bottom: 0;
        left: 0;
        right: 0;
        mask-repeat: no-repeat;
        mask-position: center;
        mask-size: contain;
    }

    &::before {
        mask-size: 80%;
    }

    &.mx_EventTile_e2eIcon_warning::after {
        mask-image: url('$(res)/img/e2e/warning.svg');
        background-color: $alert;
    }

    &.mx_EventTile_e2eIcon_normal::after {
        mask-image: url('$(res)/img/e2e/normal.svg');
        background-color: $header-panel-text-primary-color;
    }
}

.mx_EventTile_body {
    a:hover {
        text-decoration: underline;
    }

    pre {
        border: 1px solid transparent;

        .mx_EventTile:hover &,
        .mx_EventTile.focus-visible:focus-within & {
            border: 1px solid $tertiary-content;
        }
    }

    // selector wrongly applies to pill avatars but those have explicit width/height passed at a higher specificity
    &.markdown-body img {
        object-fit: contain;
        object-position: left top;
    }

    .mx_EventTile_clamp & {
        -webkit-line-clamp: 2;
        -webkit-box-orient: vertical;
        overflow: hidden;
        text-overflow: ellipsis;
        display: -webkit-box;
    }

    .mx_EventTile_pre_container {
        // For correct positioning of _copyButton (See TextualBody)
        position: relative;

        &:focus-within,
        &:hover {
            .mx_EventTile_button {
                visibility: visible;
            }
        }

        .mx_EventTile_collapsedCodeBlock {
            max-height: 30vh;
        }

        // Inserted adjacent to <pre> blocks, (See TextualBody)
        .mx_EventTile_button {
            position: absolute;
            top: $spacing-8;
            right: $spacing-8;
            width: 19px;
            height: 19px;
            visibility: hidden;
            background-color: $message-action-bar-fg-color;

            &.mx_EventTile_buttonBottom {
                top: 33px;
            }

            &.mx_EventTile_collapseButton,
            &.mx_EventTile_expandButton {
                mask-size: 75%;
            }
        }

        .mx_EventTile_copyButton {
            height: 17px;
            mask-image: url($copy-button-url);
            mask-position: center center;
            mask-repeat: no-repeat;
            mask-size: contain;
            right: 9px;
            width: 17px;
        }
    }
}

.mx_EventTile_lineNumbers {
    float: left;
    margin: 0 0.5em 0 -1.5em;
    color: gray;

    & span {
        text-align: right;
        display: block;
        padding-left: 1em;
    }
}

.mx_EventTile_button {
    display: inline-block;
    cursor: pointer;
}

.mx_EventTile_collapseButton,
.mx_EventTile_expandButton {
    mask-position: center;
    mask-repeat: no-repeat;
}

.mx_EventTile_collapseButton {
    mask-image: url("$(res)/img/element-icons/minimise-collapse.svg");
}

.mx_EventTile_expandButton {
    mask-image: url("$(res)/img/element-icons/maximise-expand.svg");
}

.mx_EventTile_keyRequestInfo {
    font-size: $font-12px;

    .mx_EventTile_keyRequestInfo_text {
        opacity: 0.5;

        .mx_AccessibleButton {
            color: $primary-content;
            text-decoration: underline;
        }
    }
}

.mx_EventTile_keyRequestInfo_tooltip_contents p {
    text-align: auto;
    margin-left: 3px;
    margin-right: 3px;

    &:first-child {
        margin-top: 0px;
    }

    &:last-child {
        margin-bottom: 0px;
    }
}

.mx_EventTile_tileError {
    color: red;
    text-align: center;

    // Remove some of the default tile padding so that the error is centered
    margin-right: 0;

    .mx_EventTile_line {
        padding-left: 0;
        margin-right: 0;

        span {
            padding: $spacing-4 $spacing-8;
        }
    }

    a {
        margin-left: 1em;
    }
}

.mx_EventTile:hover .mx_MessageActionBar,
.mx_EventTile.mx_EventTile_actionBarFocused .mx_MessageActionBar,
[data-whatinput='keyboard'] .mx_EventTile:focus-within .mx_MessageActionBar,
.mx_EventTile.focus-visible:focus-within .mx_MessageActionBar {
    visibility: visible;
}

// Inverse of the above to *disable* the animation on any indicators. This approach
// is less pretty, but is easier to target because otherwise we need to define the
// animation for when it's shown which means duplicating the style definition in
// multiple places.
.mx_EventTile:not(:hover):not(.mx_EventTile_actionBarFocused):not([data-whatinput='keyboard'] :focus-within) {
    &:not(.focus-visible:focus-within) .mx_MessageActionBar .mx_Indicator {
        animation: none;
    }
}

.mx_EventTile[data-shape="ThreadsList"] {
    --topOffset: $spacing-12;
    --leftOffset: 48px;
    $borderRadius: 8px;
    $padding: $spacing-8;
    $hrHeight: 1px;
    $notification-dot-size: 8px; // notification dot next to the timestamp

    margin: calc(var(--topOffset) + $hrHeight) 0 var(--topOffset); // include the height of horizontal line
    padding: $padding $spacing-24 $padding $padding;
    border-radius: $borderRadius;

    display: flex;
    flex-flow: wrap;
    align-items: center;

    &::after,
    &::before {
        content: "";
        position: absolute;
    }

    &::after {
        $inset-block-start: auto;
        $inset-inline-end: calc(32px - $padding);
        $inset-block-end: calc(-1 * var(--topOffset) - $hrHeight); // exclude the height of horizontal line
        $inset-inline-start: calc(var(--leftOffset) + $padding);
        inset: $inset-block-start $inset-inline-end $inset-block-end $inset-inline-start;

        height: $hrHeight;
        background-color: $quinary-content;
        pointer-events: none; // disable the message action bar on hover
    }

    &::before {
        inset: 0;
    }

    // Display notification dot
    &[data-notification]::before {
        $notification-inset-block-start: 14px; // 14px: align the dot with the timestamp row

        width: $notification-dot-size;
        height: $notification-dot-size;
        border-radius: 50%;
        inset: $notification-inset-block-start $spacing-8 auto auto;
    }

    &[data-notification="total"]::before {
        background-color: $room-icon-unread-color;
    }

    &[data-notification="highlight"]::before {
        background-color: $alert;
    }

    &:last-child {
        &::after {
            content: unset;
        }

        margin-bottom: 0;
    }

    &:first-child {
        margin-top: 0;
    }

    .mx_EventTile_avatar {
        inset: $padding auto auto $padding;
    }

    .mx_DisambiguatedProfile {
        margin-inline: 0 $spacing-12;
        display: inline-flex;
        flex: 1;

        .mx_DisambiguatedProfile_displayName,
        .mx_DisambiguatedProfile_mxid {
            display: block;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        .mx_DisambiguatedProfile_displayName {
            flex: none;
            max-width: 100%;
        }

        .mx_DisambiguatedProfile_mxid {
            flex: 1;
        }
    }

    .mx_EventTile_line {
        width: 100%;
        box-sizing: border-box;
        padding-bottom: 0;

        .mx_ThreadPanel_replies {
            margin-top: $spacing-8;
            display: flex;
            align-items: center;
            position: relative;

            &::before {
                @mixin ThreadSummaryIcon;
            }

            .mx_ThreadPanel_replies_amount {
                @mixin ThreadRepliesAmount;
                line-height: var(--EventTile_ThreadSummary-line-height);
                font-size: $font-12px; // Same font size as the counter on the main panel
            }

            .mx_ThreadSummary_content {
                text-overflow: ellipsis;
                overflow: hidden;
                white-space: nowrap;
            }
        }
    }

    .mx_DisambiguatedProfile,
    .mx_EventTile_line {
        padding-inline-start: var(--leftOffset);
    }

    .mx_MessageTimestamp {
        font-size: $font-12px;
        max-width: var(--MessageTimestamp-max-width);
        position: initial;
    }

    &:hover {
        background-color: $system;
    }

    // ThreadsList has always group layout
    &[data-layout="group"]:hover {
        .mx_EventTile_line {
            background-color: $system; // override $event-selected-color
            box-shadow: none; // don't show the verification left stroke in the thread list
        }
    }
}

// For style rules of ThreadView, see _ThreadPanel.pcss
.mx_ThreadView {
    --ThreadView_group_spacing-start: 56px; // 56px: 64px - 8px (padding)
    --ThreadView_group_spacing-end: 8px; // same as padding

    .mx_EventTile {
        display: flex;
        flex-direction: column;

        .mx_EventTile_roomName {
            display: none;
        }

        .mx_EventTile_line {
            padding-block: var(--BaseCard_EventTile_line-padding-block);
        }

        .mx_EventTile_line,
        .mx_ReactionsRow {
            padding-inline-start: 0; // Cancel inherited padding value for event message and reactions row
        }

        .mx_ReactionsRow {
            padding-inline-end: 0;
        }

        // handling for hidden events (e.g reactions) in the thread view
        &.mx_EventTile_info {
            .mx_EventTile_avatar {
                position: absolute;
                top: 1.5px; // Align with hidden event content
                margin-top: 0;
                margin-bottom: 0;
                width: 14px; // avatar img size
                height: 14px; // avatar img size
            }

            .mx_ViewSourceEvent_toggle {
                display: none; // hide the hidden event expand button, not enough space, view source can still be used
            }

            &.mx_EventTile_selected .mx_EventTile_line,
            .mx_EventTile_line {
                $line-height: $font-12px;

                padding-inline-start: 0;
                line-height: $line-height;

                .mx_EventTile_content,
                .mx_RedactedBody {
                    width: auto;
                    // 14px: avatar width, 6px: 20px - 14px
                    margin-inline-start: calc(var(--ThreadView_group_spacing-start) + 14px + 6px);
                    font-size: $line-height;
                }
            }

            &[data-layout="irc"],
            &[data-layout="group"] {
                padding-top: 0;

                .mx_EventTile_avatar {
                    left: calc($MessageTimestamp_width + 14px - 4px); // 14px: avatar width, 4px: align with text
                    z-index: 9; // position above the hover styling
                }

                .mx_MessageTimestamp {
                    top: 2px; // Align with avatar
                }
            }

            &[data-layout="bubble"] {
                .mx_EventTile_avatar {
                    inset-inline-start: 0;
                }
            }
        }

        &[data-layout="irc"],
        &[data-layout="group"] {
            padding-block-start: $spacing-16;

            .mx_EventTile_line {
                .mx_EventTile_content {
                    &.mx_EditMessageComposer {
                        padding-inline-start: 0; // align start of first letter with that of the event body
                    }
                }
            }
        }

        &[data-layout="group"] {
            width: 100%;

            .mx_EventTile_content,
            .mx_HiddenBody,
            .mx_RedactedBody,
            .mx_UnknownBody,
            .mx_MPollBody,
            .mx_MLocationBody,
            .mx_ReplyChain_wrapper,
            .mx_ReactionsRow {
                margin-inline-start: var(--ThreadView_group_spacing-start);
                margin-inline-end: var(--ThreadView_group_spacing-end);

                .mx_EventTile_content,
                .mx_HiddenBody,
                .mx_RedactedBody,
                .mx_MImageBody {
                    margin: 0;
                }
            }

            .mx_ReplyChain_wrapper {
                .mx_MLocationBody,
                .mx_UnknownBody { // Error message inside ReplyTile
                    margin-inline: unset;
                }
            }

            .mx_EventTile_mediaLine {
                // such as MImageBody
                > div,
                > span {
                    margin-inline-start: var(--ThreadView_group_spacing-start);
                    margin-inline-end: var(--ThreadView_group_spacing-end);
                }

                // such as MAudioBody and MFileBody
                > span {
                    display: block; // Apply the margin declarations to span element
                }
            }

            .mx_EventTile_senderDetails {
                display: flex;
                align-items: center;
                gap: $spacing-16; // gap between the avatar and the sender ID
                padding-inline-start: $spacing-8;

                a {
                    flex: 1;
                    min-width: unset;
                    max-width: 100%;
                    display: flex;
                    align-items: center;

                    .mx_DisambiguatedProfile {
                        margin-left: 8px;
                        flex: 1;
                    }
                }
            }

            .mx_MessageTimestamp {
                position: absolute; // for IRC layout
                top: 2px; // Align with mx_EventTile_content
            }

            &:hover {
                &.mx_EventTile_verified.mx_EventTile_info .mx_EventTile_line,
                &.mx_EventTile_unverified.mx_EventTile_info .mx_EventTile_line,
                &.mx_EventTile_unknown.mx_EventTile_info .mx_EventTile_line {
                    padding-inline-start: 0;
                }
            }
        }

        &[data-layout="bubble"] {
            margin-inline: var(--BaseCard_EventTile-spacing-inline);

            &::before {
                inset-inline: calc(-1 * var(--BaseCard_EventTile-spacing-inline));
                z-index: auto; // enable background color on hover
            }

            .mx_ReactionsRow {
                position: relative; // display on hover
            }

            .mx_EventTile_line.mx_EventTile_mediaLine {
                padding-block: 0;
                padding-inline-start: 0;
                max-width: var(--EventBubbleTile_line-max-width);
            }

            &[data-self="true"] {
                align-items: flex-end;

                .mx_EventTile_line.mx_EventTile_mediaLine {
                    margin: 0 var(--EventTile_bubble_line-margin-inline-end) 0 0; // align with normal messages
                }
            }
        }
    }

    .mx_GenericEventListSummary {
        &[data-layout="irc"],
        &[data-layout="group"] {
            > .mx_EventTile_line {
                padding-inline-start: var(--ThreadView_group_spacing-start); // align summary text with message text
                padding-inline-end: var(--ThreadView_group_spacing-end); // align summary text with message text
            }
        }
    }
}

// Cascading - compact modern layout on the main timeline and the right panel
.mx_MatrixChat_useCompactLayout {
    .mx_EventTile {
        // Override :not([data-layout="bubble"])
        &[data-layout="group"] {
            --MatrixChat_useCompactLayout_group-padding-top: $spacing-4;
            --MatrixChat_useCompactLayout-top-avatar: 2px;
            --MatrixChat_useCompactLayout-top-e2eIcon: 3px;
            --MatrixChat_useCompactLayout_line-spacing-block: 0px;

            padding-top: var(--MatrixChat_useCompactLayout_group-padding-top);

            .mx_EventTile_line,
            .mx_EventTile_reply {
                padding-block: var(--MatrixChat_useCompactLayout_line-spacing-block);
            }

            &.mx_EventTile_info {
                padding-top: 0; // same as the padding for non-compact .mx_EventTile.mx_EventTile_info
                font-size: $font-13px;

                .mx_EventTile_e2eIcon,
                .mx_EventTile_avatar {
                    top: 0;
                    margin-block: var(--MatrixChat_useCompactLayout_line-spacing-block);
                }

                .mx_EventTile_line,
                .mx_EventTile_reply {
                    line-height: $font-20px;
                }
            }

            &.mx_EventTile_emote {
                padding-top: $spacing-8; // add a bit more space for emotes so that avatars don't collide

                .mx_EventTile_avatar {
                    top: var(--MatrixChat_useCompactLayout-top-avatar);
                }

                .mx_EventTile_line,
                .mx_EventTile_reply {
                    padding-bottom: 1px;
                }

                &.mx_EventTile_continuation {
                    .mx_EventTile_line,
                    .mx_EventTile_reply {
                        padding-bottom: var(--MatrixChat_useCompactLayout_line-spacing-block);
                    }
                }
            }

            // Cascading - apply zero padding to every element including mx_EventTile_emote
            &.mx_EventTile_continuation {
                padding-top: var(--MatrixChat_useCompactLayout_line-spacing-block);
            }

            .mx_EventTile_avatar {
                top: var(--MatrixChat_useCompactLayout-top-avatar);
            }

            .mx_EventTile_e2eIcon {
                top: var(--MatrixChat_useCompactLayout-top-e2eIcon);
            }

            .mx_DisambiguatedProfile {
                font-size: $font-13px;
            }

            .mx_EventTile_msgOption {
                .mx_ReadReceiptGroup {
                    // This aligns the avatar with the last line of the
                    // message. We want to move it one line up - 2rem
                    inset-block-start: -2rem;
                }
            }

            .mx_EventTile_content .markdown-body {
                p,
                ul,
                ol,
                dl,
                blockquote,
                pre,
                table {
                    margin-bottom: $spacing-4; // 1/4 of the non-compact margin-bottom
                }
            }
        }

        &[data-shape="ThreadsList"][data-notification]::before {
            /* stylelint-disable-next-line declaration-colon-space-after */
            inset-block-start:
                calc($notification-inset-block-start - var(--MatrixChat_useCompactLayout_group-padding-top));
        }
    }
}

// Media query for mobile UI
@media only screen and (max-width: 480px) {
    .mx_EventTile_content {
        margin-right: 0;
    }
}