Trilium/apps/client/src/widgets/layout/Breadcrumb.css

.breadcrumb-row {
    position: relative;
    min-height: 30px;
    align-items: center;

    .breadcrumb {
        display: flex;
        margin: 0;
        align-items: center;
        font-size: 0.9em;
        gap: 0.25em;
        flex-wrap: nowrap;
        overflow: hidden;

        > span,
        > span > span {
            display: flex;
            align-items: center;
            min-width: 0;

            a {
                color: inherit;
                text-decoration: none;
                min-width: 0;
                max-width: 150px;
                text-overflow: ellipsis;
                white-space: nowrap;
                overflow: hidden;
                display: block;
                flex-shrink: 2;
            }
        }

        > span:last-of-type a {
            max-width: 300px;
            flex-shrink: 1;
        }

        ul {
            flex-direction: column;
            list-style-type: none;
            margin: 0;
            padding: 0;
        }

        .dropdown-item span,
        .dropdown-item strong,
        .breadcrumb-last-item {
            text-overflow: ellipsis;
            white-space: nowrap;
            overflow: hidden;
            display: block;
            max-width: 300px;
        }

        .breadcrumb-last-item {
            text-decoration: none;
            color: unset;
            cursor: text;
        }

        input {
            padding: 0 10px;
            width: 200px;
        }
    }
}

body.experimental-feature-new-layout .breadcrumb-row {
    padding-inline-end: 0;
}