element-web-Github/res/css/views/rooms/_ReplyPreview.pcss

/*
Copyright 2018 Vector Creations Ltd

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.
*/

.mx_ReplyPreview {
    border: 1px solid $primary-hairline-color;
    border-bottom: none;
    background: $background;
    max-height: 50vh;
    overflow: auto;

    .mx_ReplyPreview_section {
        border-bottom: 1px solid $primary-hairline-color;
        display: flex;
        flex-flow: column;
        row-gap: $spacing-8;
        padding: $spacing-8 $spacing-8 0 $spacing-8;

        .mx_ReplyPreview_header {
            display: flex;
            justify-content: space-between;
            column-gap: 8px;

            color: $primary-content;
            font-weight: 400;
            opacity: 0.4;

            .mx_ReplyPreview_header_cancel {
                background-color: $primary-content;
                mask: url('$(res)/img/cancel.svg');
                mask-repeat: no-repeat;
                mask-position: center;
                mask-size: 18px;
                width: 18px;
                height: 18px;
                min-width: 18px;
                min-height: 18px;
            }
        }
    }
}

.mx_RoomView_body {
    .mx_ReplyPreview {
        /* Add box-shadow to the reply preview on the main (left) panel only. */
        /* It is not added to the preview on the (right) panel for threads and a chat with a maximized widget. */
        box-shadow: 0px -16px 32px $composer-shadow-color;
        border-radius: 8px 8px 0 0;
    }
}