riot-web/res/css/views/rooms/_GroupLayout.scss

/*
Copyright 2015, 2016 OpenMarket Ltd
Copyright 2020 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_GroupLayout {
    .mx_EventTile {
        > .mx_SenderProfile {
            line-height: $font-20px;
            margin-left: $left-gutter;
        }

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

        .mx_MessageTimestamp {
            position: absolute;
            width: $MessageTimestamp_width;
        }

        .mx_EventTile_line, .mx_EventTile_reply {
            padding-top: 1px;
            padding-bottom: 3px;
            line-height: $font-22px;
        }
    }
}

/* Compact layout overrides */

.mx_MatrixChat_useCompactLayout {
    .mx_EventTile {
        padding-top: 4px;

        .mx_EventTile_line, .mx_EventTile_reply {
            padding-top: 0;
            padding-bottom: 0;
        }

        &.mx_EventTile_info {
            // same as the padding for non-compact .mx_EventTile.mx_EventTile_info
            padding-top: 0px;
            font-size: $font-13px;
            .mx_EventTile_line, .mx_EventTile_reply {
                line-height: $font-20px;
            }
            .mx_EventTile_avatar {
                top: 4px;
            }
        }

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

        &.mx_EventTile_emote {
            // add a bit more space for emotes so that avatars don't collide
            padding-top: 8px;
            .mx_EventTile_avatar {
                top: 2px;
            }
            .mx_EventTile_line, .mx_EventTile_reply {
                padding-top: 0px;
                padding-bottom: 1px;
            }
        }

        &.mx_EventTile_emote.mx_EventTile_continuation {
            padding-top: 0;
            .mx_EventTile_line, .mx_EventTile_reply {
                padding-top: 0px;
                padding-bottom: 0px;
            }
        }

        .mx_EventTile_avatar {
            top: 2px;
        }

        .mx_EventTile_e2eIcon {
            top: 3px;
        }

        .mx_EventTile_readAvatars {
            // This aligns the avatar with the last line of the
            // message. We want to move it one line up - 2rem
            top: -2rem;
        }

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

    .mx_RoomView_MessageList h2 {
        margin-top: 6px;
    }
}