html {
    scroll-behavior: smooth;
}

main {
    position: relative;
    z-index: 1;
}

#main-content {
    margin-top: -60px; /* pull content up under nav (adjust height to match your nav) */
    min-height: 500px;
}

[id^="section_"] {
    scroll-margin-top: 129px; /* altura de tus 2 menús */
}