bitwarden-desktop/src/scss/environment.scss

html.os_windows {
    body {
        border-top: 1px solid #dddddd;
    }

    &.theme_dark body {
        border-top-color: #000000;
    }
}

html.os_macos {
    body.layout_frontend {
        -webkit-app-region: drag;

        button, a, i, b, span, input, p, h1, h2, h3, h4, h5, h6, img, select,
        textarea, label, .box, .modal-backdrop {
            -webkit-app-region: no-drag;
        }
    }

    #login-page {
        .content {
            a.settings-icon {
                position: absolute;
                left: unset;
                right: 20px;

                span {
                    margin-right: 8px;
                    float: left;
                }
            }
        }
    }

    #vault .header-search {
        -webkit-app-region: drag;

        input, i {
            -webkit-app-region: no-drag;
        }
    }

    #vault .mac-bar {
        height: 48px;
        -webkit-app-region: drag;
    }

    #vault > #groupings > .content > .inner-content {
        padding-top: 0;
    }
}