Userscripts.org

This code should handle scaling the feed list dependent on the font size. If you want to change the spacing, adjust the 1.5em value in both places. Changing the value down will squeeze the items closer together and increasing the value will spread the items further apart.

.lhn-section-primary, 
#recommendations-tree .lhn-section-primary, 
.scroll-tree li.folder .link, 
.scroll-tree li.sub {
    height: 1.5em !important; }
.lhn-section-primary, 
#reading-list-unread-count, 
.scroll-tree {
    line-height: 1.5em !important; }
.section-minimize { 
    top: auto !important; }
#reading-list-unread-count { 
    margin-top: auto !important; }

Try this:

.entry .entry-body { 
  line-height: 1.5em !important; }

This is the code I use for the post spacing:

/* expanded view */ 
#entries.cards .entry { 
    margin: 0 !important; } 
#entries.cards .card-content { 
    padding: 5px !important; } 
/* list view */ 
#entries.list .collapsed .entry-source-title, 
#entries.list .collapsed .entry-title, 
#entries.list .collapsed .entry-date { 
    line-height: 1.5em !important; } 
#entries.list .entry .collapsed { 
    height: 1.5em !important; } 
#entries.list .expanded .entry-secondary-snippet { 
    display: none !important; }