element-web-Github/res/css/views/messages/_ViewSourceEvent.pcss

/*
Copyright 2024 New Vector Ltd.
Copyright 2019 The Matrix.org Foundation C.I.C.

SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
Please see LICENSE files in the repository root for full details.
*/

.mx_EventTile_content.mx_ViewSourceEvent {
    display: flex;
    opacity: 0.6;
    font-size: $font-12px;
    width: 100%;
    overflow-x: auto; /* Cancel overflow setting of .mx_EventTile_content */
    line-height: normal; /* Align with avatar and E2E icon */

    pre,
    code {
        flex: 1;
    }

    pre {
        line-height: 1.2;
        margin: 3.5px 0;
    }

    .mx_ViewSourceEvent_toggle {
        --ViewSourceEvent_toggle-size: 12px;

        visibility: hidden;
        /* override styles from AccessibleButton */
        border-radius: 0;
        /* icon */
        mask-repeat: no-repeat;
        mask-position: 0 center;
        mask-size: auto var(--ViewSourceEvent_toggle-size);
        width: var(--ViewSourceEvent_toggle-size);
        min-width: var(--ViewSourceEvent_toggle-size);
        background-color: $accent;
        mask-image: url("$(res)/img/element-icons/maximise-expand.svg");

        .mx_EventTile:hover & {
            visibility: visible;
        }
    }

    &.mx_ViewSourceEvent_expanded .mx_ViewSourceEvent_toggle {
        align-self: flex-end;
        height: var(--ViewSourceEvent_toggle-size);
        mask-position: 0 bottom;
        margin-bottom: 5px;
        mask-image: url("$(res)/img/element-icons/minimise-collapse.svg");
    }
}