converse.js/sass/_controlbox.scss

#conversejs {
    .oauth-providers {
        text-align: center;
        .oauth-provider {
            margin: 1em 0;

            .oauth-login {
                margin-left: 0;
                color: var(--link-color);
                font-size: var(--font-size-large);
                &:hover {
                    color: var(--link-hover-color);
                }
                i {
                    color: var(--link-color);
                    font-size: var(--font-size-huge);
                    margin-right: 0.5em;
                }
            }
        }
    }

    .set-xmpp-status,
    .xmpp-status {
        .chat-status--online {
            color: var(--chat-status-online);
        }
        .chat-status--busy {
            color: var(--chat-status-busy);
        }
        .chat-status--away {
            color: var(--chat-status-away);
        }
        .far.fa-circle,
        .fa-times-circle {
            color: var(--subdued-color);
        }
    }

    .set-xmpp-status {
        .chat-status {
            padding-right: 0.5em;
        }
    }

    .room-info {
        font-size: var(--font-size-small);
        font-style: normal;
        font-weight: normal;

        li.room-info {
            display: block;
            margin-left: 5px;
        }
        p.room-info {
            line-height: var(--line-height);
            margin: 0;
            display: block;
            white-space: normal;
        }
    }
    div.room-info {
        padding: 0.3em 0;
        clear: left;
        width: 100%;
    }

    #controlbox {
        order: -1;
        color: var(--controlbox-text-color);

        converse-brand-logo {
            width: 100%;
            display: block;
        }

        converse-brand-heading {
            width: 100%;
            display: block;
        }

        .brand-name-wrapper {
            font-size: 200%;
        }

        .brand-name-wrapper--fullscreen {
            font-size: 100%;
        }

        .open-rooms-toggle, .open-rooms-toggle .fa {
            color: var(--groupchats-header-color) !important;
            &:hover {
                color: var(--chatroom-head-bg-color-dark) !important;
            }
        }

        .box-flyout {
            background-color: var(--controlbox-pane-background-color);
        }

        margin-right: calc(3 * var(--chat-gutter));

        &.logged-out {
            .box-flyout {
                .controlbox-pane {
                    overflow-y: auto;
                }
            }
        }

        form.search-xmpp-contact {
            margin: 0;
            padding-left: 5px;
            padding: 0 0 5px 5px;
            input {
                width: 8em;
            }
        }

        .msgs-indicator {
            margin-right: 0.5em;
        }

        a.subscribe-to-user {
            padding-left: 2em;
            font-weight: bold;
        }

        #converse-register {
            @include fade-in;
            background-color: var(--controlbox-pane-background-color);
            .title {
                font-weight: bold;
            }
            .info {
                color: green;
                font-size: 90%;
                margin: 1.5em 0;
            }
            .form-errors {
                color: var(--error-color);
                margin: 1em 0;
            }
            .provider-title {
                font-size: var(--font-size-huge);
                margin: 0;
            }
            .provider-score {
                width: 178px;
                margin-bottom: 8px;
            }
            .form-help .url {
                font-weight: bold;
                color: var(--link-color);
            }
            .input-group {
                display: table;
                margin: auto;
                width: 100%;
                span {
                    overflow-x: hidden;
                    text-overflow: ellipsis;
                    max-width: 110px;
                }
                span, input[name=username] {
                    display: table-cell;
                    text-align: left;
                }
            }
            .instructions {
                color: gray;
                font-size: 85%;
                &:hover {
                    color: var(--controlbox-text-color);
                }
            }
        }

        .conn-feedback {
            color: var(--controlbox-head-color);
            &.error {
                color: var(--error-color);
            }
            p {
                padding-bottom: 1em;
                &.feedback-subject.error {
                    font-weight: bold;
                }
            }
        }

        #converse-login-panel, #converse-register-panel {
            padding-top: 0;
            padding-bottom: 0;
        }

        #converse-login-panel {
            flex-direction: row;
        }

        .toggle-register-login {
            font-weight: bold;
        }

        .controlbox-pane {
            .userinfo {
                padding-bottom: 1em;

                .username {
                    margin-left: 0.5em;
                    overflow: hidden;
                    text-overflow: ellipsis;
                }
                .profile {
                    margin-bottom: 0.75em;
                }
            }
        }

        #chatrooms {
            padding: 0;

            .add-chatroom {
                input[type=button],
                input[type=submit],
                input[type=text] {
                    width: 100%;
                }
                margin: 0;
                padding: 0;
            }
        }

        .controlbox-section {

            .controlbox-heading {
                font-family: var(--heading-font);
                color: var(--controlbox-heading-color);
                font-weight: var(--controlbox-heading-font-weight);
                padding: 0;
                font-size: 1.1em;
                line-height: 1.1em;
                text-transform: uppercase;
            }

            .controlbox-heading--groupchats {
                color: var(--groupchats-header-color);
            }

            .controlbox-heading--contacts {
                color: var(--chat-head-color-dark);
            }

            .controlbox-heading--headline {
                color: var(--headline-head-color);
            }

            .controlbox-heading__btn {
                cursor: pointer;
                font-size: 1em;
                padding: 0;
                margin: var(--controlbox-heading-top-margin) 0 var(--inline-action-margin) 0;
                min-width: 25px;
                text-align: center;
                &.fa-vcard {
                    margin-top: 1em;
                }
            }
        }

        .dropdown {
            a {
                width: 143px;
                display: inline-block;
            }
            li {
                list-style: none;
                padding-left: 0;
            }
            dd {
                ul {
                    padding: 0;
                    list-style: none;
                    position: absolute;
                    left: 0;
                    top: 0;
                    width: 100%;
                    z-index: 21;
                    background-color: var(--light-background-color);
                    li:hover {
                        background-color: var(--highlight-color);
                    }
                }
            }

            dd.search-xmpp {
                height: 0;
                .contact-form-container {
                    position: absolute;
                    z-index: 22;
                    form {
                        box-shadow: 1px 4px 10px 1px rgba(0, 0, 0, 0.4);
                        background-color: white;
                    }
                }
                li:hover {
                    background-color: var(--light-background-color);
                }
            }
            dt a span {
                cursor: pointer;
                display: block;
                padding: 4px 7px 0 5px;
            }
        }

        .controlbox-panes {
            background-color: var(--controlbox-pane-background-color);
            border-right: 0.2143rem solid var(--panel-divider-color);
            height: 100%;
            overflow-y: auto;
        }

        .controlbox-subtitle {
            font-size: 90%;
            padding: 0.5em;
            text-align: right;
        }

        .controlbox-pane {
            background-color: var(--controlbox-pane-background-color);
            border: 0;
            font-size: var(--font-size);
            left: 0;
            text-align: left;
            overflow-x: hidden;
            padding: 0 0 1em 0;

            .controlbox-padded {
                padding-left: 1em;
                padding-right: 1em;
                align-items: center;
                line-height: normal;
                .change-status {
                    min-width: 25px;
                    text-align: center;
                }
            }

            .add-converse-contact {
                margin: 0 0 0.75em 0;
            }

            .chatbox-btn {
                margin: 0;
            }

            .switch-form {
                text-align: center;
                padding: 2em 0;
            }
            dd {
                margin-left: 0;
                margin-bottom: 0;
                &.odd {
                    background-color: #DCEAC5;
                }
            }
        }

        .add-xmpp-contact {
            padding: 1em 0.5em;
            input {
                margin: 0 0 1rem;
                width: 100%;
            }
            button {
                width: 100%;
            }
        }
    }
}

#conversejs {
    converse-chats {
        &.converse-overlayed {

            display: flex;
            flex-direction: row-reverse;

            .toggle-controlbox {
                order: -2;
                text-align: center;
                background-color: var(--link-color);
                border-top-left-radius: var(--button-border-radius);
                border-top-right-radius: var(--button-border-radius);
                color: #0a0a0a;
                float: right;
                height: 100%;
                margin: 0 var(--chat-gutter);
                padding: 1em;
                span {
                    color: var(--inverse-link-color);
                }
            }

            #controlbox {
                order: -1;
                min-width: var(--controlbox-width) !important;
                width: var(--controlbox-width);
                .box-flyout {
                    min-width: var(--controlbox-width) !important;
                    width: var(--controlbox-width);
                }

                .login-trusted {
                    white-space: nowrap;
                    font-size: 90%;
                }

                #converse-login-trusted {
                    margin-top: 0.5em;
                }
                &:not(.logged-out) {
                    .controlbox-head {
                        height: 15px;
                    }
                }

                .controlbox-head {
                    display: flex;
                    flex-direction: row-reverse;
                    flex-wrap: nowrap;
                    justify-content: space-between;
                    min-height: 0;

                    .brand-heading {
                        color: var(--controlbox-text-color);
                        font-size: 2em;
                    }
                    .chatbox-btn {
                        color: var(--controlbox-head-color);
                        margin: 0;
                    }
                }

                #converse-register, #converse-login {
                    @include make-col(12);
                    padding-bottom: 0;
                }

                #converse-register {
                    .button-cancel {
                        font-size: 90%;
                    }
                }

                .controlbox-panes {
                    border-radius: var(--chatbox-border-radius);
                }
            }
        }

        &.converse-embedded,
        &.converse-fullscreen{
            .toggle-controlbox {
                display: none;
            }
        }

        &.converse-embedded,
        &.converse-fullscreen,
        &.converse-mobile {
            #controlbox {
                @include make-col-ready();

                @include media-breakpoint-up(md) {
                    @include make-col(4);
                }
                @include media-breakpoint-up(lg) {
                    @include make-col(3);
                }
                @include media-breakpoint-up(xl) {
                    @include make-col(2);
                }

                &.logged-out {
                    @include make-col(12);
                }

                margin: 0;

                .flyout {
                    border-radius: 0;
                }

                #converse-login-panel {
                    border-radius: 0;
                    .converse-form {
                        padding: 3em 2em 3em;
                    }
                }

                .toggle-register-login {
                    line-height: var(--line-height-huge);
                }

                converse-brand-logo {
                    @include make-col(12);
                    margin-top: 5em;
                    margin-bottom: 1em;
                    .brand-heading {
                        width: 100%;
                        font-size: 500%;
                        padding: 0.7em 0 0 0;
                        opacity: 0.8;
                        color: var(--brand-heading-color);
                    }
                    .brand-subtitle {
                        font-size: 90%;
                        padding: 0.5em;
                    }
                    @media screen and (max-width: $mobile-portrait-length) {
                        .brand-heading {
                            font-size: 300%;
                        }
                    }
                }

                &.logged-out {
                    @include make-col(12);
                    @include fade-in;
                    width: 100%;
                    .box-flyout {
                        width: 100%;
                    }
                }
                .box-flyout {
                    border: 0;
                    width: 100%;
                    z-index: 1;
                    background-color: var(--controlbox-head-color);

                    .controlbox-head {
                        display: none;
                    }
                }

                #converse-register, #converse-login {
                    @include make-col-ready();
                    @include make-col(8);
                    @include make-col-offset(2);

                    @include media-breakpoint-up(sm) {
                        @include make-col(8);
                        @include make-col-offset(2);
                    }
                    @include media-breakpoint-up(md) {
                        @include make-col(8);
                        @include make-col-offset(2);
                    }
                    @include media-breakpoint-up(lg) {
                        @include make-col(6);
                        @include make-col-offset(3);
                    }
                    .title, .instructions {
                        margin: 1em 0;
                    }
                    input[type=submit],
                    input[type=button] {
                        width: auto;
                    }
                }
            }
        }

        &.converse-fullscreen {
            #controlbox {
                margin-left: -15px;
            }
            .controlbox-panes {
                padding-top: 2em;
            }
        }

        &.converse-overlayed {
            .brand-heading {
                padding-top: 0.8rem;
                padding-left: 0.8rem;
                width: 100%;
            }
            .converse-svg-logo {
                height: 1em;
            }
            #controlbox {
                #converse-login-panel {
                    height: 100%;
                }
                .controlbox-panes {
                    margin-top: 0.5em;
                }
            }
        }
    }
}

@include media-breakpoint-down(sm) {

    #conversejs {
        left: 0;
        right: 0;
        padding-left: env(safe-area-inset-left);
        padding-right: env(safe-area-inset-right);

        .converse-chatboxes {
            margin: 0 !important;
            flex-direction: row !important;
            justify-content: space-between;

            .converse-chatroom {
                font-size: 14px;
            }

            .chatbox {
                .box-flyout {
                    margin-left: 15px; // Counteracts Bootstrap margins, but not clear why needed...
                    left: 0;
                    bottom: 0;
                    border-radius: 0;
                    width: 100vw !important;
                    height: var(--fullpage-chat-height);
                }
            }

            #controlbox {
                width: 100vw !important;
                .box-flyout {
                    width: 100vw !important;
                    height: var(--fullpage-chat-height);
                    margin-right: -15px;
                }
                .sidebar {
                    display: block;
                }
            }

            &.sidebar-open {
                .chatbox:not(#controlbox) {
                    display: none;
                }
                #controlbox {
                    .controlbox-pane {
                        display: block;
                    }
                }
            }
        }
    }
}