Font-size change in post gets overruled

Hello,

I changed the font-size of a post under ‘theme panel’ – theme fonts – post content. I changed default size in 20 px.
This doesn’t show on the website, it gets overruled and stays font-size 17. What need I change?

This is the code on my frontend:

.tdi_78_f73, .tdi_78_f73 > p, .tdi_78_f73 .tdb-block-inner > p {
font-family: Roboto !important;
font-size: 17px !important;
line-height: 1.5 !important;
font-weight: 400 !important;
}

.td-post-content p, .td-post-content {
font-size: 20px;
}
.td-post-content p, .td-post-content {
font-size: 20px;
}
.tagdiv-type {
font-size: 15px;
line-height: 1.74;
……..

Perfect, thx.