body {
    font-family: Arial, Helvetica, sans-serif !important;
}

:root {
    --body-font-family: Arial, Helvetica, sans-serif;
}
h1, h2, h3, h4, h5, h6,
h1.module-title, h2.module-title,
h3.module-title, h4.module-title,
.page-header h1,
.page-header h2 {
    font-family: Arial, Helvetica, sans-serif !important;
}