element-web/res/css/structures/_LeftPanel.pcss

/*
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.
*/

.mx_MatrixChat--with-avatar {
    .mx_LeftPanel,
    .mx_LeftPanel .mx_LeftPanel_roomListContainer {
        background-color: transparent;
    }
}

.mx_LeftPanel_outerWrapper {
    display: flex;
    flex-direction: column;
    max-width: 50%;
    position: relative;

    /* Contain the amount of layers rendered by constraining what actually needs re-layering via css */
    contain: layout paint;
}

.mx_LeftPanel_wrapper,
.mx_LeftPanel {
    --collapsedWidth: 68px;
}

.mx_LeftPanel_wrapper {
    display: flex;
    flex-direction: row;
    flex: 1;
    height: 100%; /* ensure space panel is still scrollable with an outer wrapper */

    .mx_LeftPanel_wrapper--user {
        background-color: $roomlist-bg-color;
        display: flex;
        overflow: hidden;
        position: relative;

        &[data-collapsed] {
            max-width: var(--collapsedWidth);
        }
    }
}

.mx_LeftPanel {
    background-color: $roomlist-bg-color;

    /* Create a row-based flexbox for the space panel and the room list */
    display: flex;
    contain: content;
    position: relative;
    flex-grow: 1;
    overflow: hidden;

    /* Note: The 'room list' in this context is actually everything that isn't the tag */
    /* panel, such as the menu options, breadcrumbs, filtering, etc */
    .mx_LeftPanel_roomListContainer {
        background-color: $roomlist-bg-color;
        flex: 1 0 0;
        min-width: 0;
        /* Create another flexbox (this time a column) for the room list components */
        display: flex;
        flex-direction: column;

        .mx_LeftPanel_userHeader {
            /* 12px top, 12px sides, 20px bottom (using 13px bottom to account
             * for internal whitespace in the breadcrumbs)
             */
            padding: 12px;
            flex-shrink: 0; /* to convince safari's layout engine the flexbox is fine */

            /* Create another flexbox column for the rows to stack within */
            display: flex;
            flex-direction: column;
        }

        .mx_LeftPanel_breadcrumbsContainer {
            overflow-y: hidden;
            overflow-x: scroll;
            margin: 12px 12px 0 12px;
            flex: 0 0 auto;
            /* Create yet another flexbox, this time within the row, to ensure items stay */
            /* aligned correctly. This is also a row-based flexbox. */
            display: flex;
            align-items: center;
            contain: content;

            &.mx_IndicatorScrollbar_leftOverflow {
                mask-image: linear-gradient(90deg, transparent, black 5%);
            }

            &.mx_IndicatorScrollbar_rightOverflow {
                mask-image: linear-gradient(90deg, black, black 95%, transparent);
            }

            &.mx_IndicatorScrollbar_rightOverflow.mx_IndicatorScrollbar_leftOverflow {
                mask-image: linear-gradient(90deg, transparent, black 5%, black 95%, transparent);
            }
        }

        .mx_LeftPanel_filterContainer {
            margin: 0 12px;
            padding: 12px 0 8px;
            border-bottom: 1px solid $quinary-content;

            flex-shrink: 0; /* to convince safari's layout engine the flexbox is fine */

            /* Create a flexbox to organize the inputs */
            display: flex;
            align-items: center;

            & + .mx_RoomListHeader {
                margin-top: 12px;
            }

            .mx_LeftPanel_dialPadButton {
                width: 32px;
                height: 32px;
                border-radius: 8px;
                background-color: $panel-actions;
                position: relative;
                margin-left: 8px;

                &::before {
                    content: "";
                    position: absolute;
                    top: 8px;
                    left: 8px;
                    width: 16px;
                    height: 16px;
                    mask-image: url("$(res)/img/element-icons/call/dialpad.svg");
                    mask-position: center;
                    mask-size: contain;
                    mask-repeat: no-repeat;
                    background-color: $secondary-content;
                }
            }

            .mx_LeftPanel_exploreButton,
            .mx_LeftPanel_recentsButton {
                width: 32px;
                height: 32px;
                border-radius: 8px;
                background-color: $panel-actions;
                position: relative;
                margin-left: 8px;

                &::before {
                    content: "";
                    position: absolute;
                    top: 8px;
                    left: 8px;
                    width: 16px;
                    height: 16px;
                    mask-position: center;
                    mask-size: contain;
                    mask-repeat: no-repeat;
                    background-color: $secondary-content;
                }

                &:hover {
                    background-color: $tertiary-content;

                    &::before {
                        background-color: $background;
                    }
                }
            }

            .mx_LeftPanel_exploreButton::before {
                mask-image: url("$(res)/img/element-icons/roomlist/explore.svg");
            }

            .mx_LeftPanel_recentsButton::before {
                mask-image: url("$(res)/img/element-icons/clock.svg");
            }
        }

        .mx_RoomListHeader:first-child {
            margin-top: 12px;
        }

        .mx_LeftPanel_roomListWrapper {
            /* Make the y-scrollbar more responsive */
            padding-right: 2px;
            overflow: hidden;
            margin-top: 10px; /* so we're not up against the search/filter */
            flex: 1 0 0; /* needed in Safari to properly set flex-basis */

            &.mx_LeftPanel_roomListWrapper_stickyBottom {
                padding-bottom: 32px;
            }

            &.mx_LeftPanel_roomListWrapper_stickyTop {
                padding-top: 32px;
            }
        }

        .mx_LeftPanel_actualRoomListContainer {
            position: relative; /* for sticky headers */
            height: 100%; /* ensure scrolling still works */
        }
    }

    /* These styles override the defaults for the minimized (66px) layout */
    &.mx_LeftPanel_minimized {
        flex-grow: 0;
        min-width: unset;
        width: unset !important;

        .mx_LeftPanel_roomListContainer {
            width: var(--collapsedWidth);

            .mx_LeftPanel_userHeader {
                flex-direction: row;
                justify-content: center;
            }

            .mx_LeftPanel_filterContainer {
                /* Organize the flexbox into a centered column layout */
                flex-direction: column;
                justify-content: center;

                .mx_LeftPanel_dialPadButton {
                    margin-left: 0;
                    margin-top: 8px;
                    background-color: transparent;
                }

                .mx_LeftPanel_exploreButton,
                .mx_LeftPanel_recentsButton {
                    margin-left: 0;
                    margin-top: 8px;
                }
            }
        }
    }
}