Exported layout looks rasterized ArcMap 10.7

[KamilaBelka]

I wanto to export the layout view into vector-based graphical format for publication purposes. It seems the vector format is resolution dependant and ArcMap first rasterizes the layout and then it exports the pixels into vector form! 

The problem is that I cannot obtain a fine resolution file without a pixel-like view and the exported file is very big. 

Zoomed-in view of the original layout as seen in ArcMap window (screenshoot):

Zoomed-in view of the exported PDF in 300 dpi resolution:

I use ArcMap 10.7.

Would you please advise how to solve this problem. 

[rzufelt]

Do you have transparency set on any of the layers in the TOC?

If so, try moving them below the layer that is getting rasterized, or, turn off transparency for testing.

R_

[JimCousins]

A little information?

Are you exporting or printing to PDF?

What size is your layout, 8.5x11 11x17 etc

What are your settings under the export options in the General and Format tabs?