userChrome.css

/*
about:config
toolkit.legacyUserProfileCustomizations.stylesheets = true
about:support
~/.mozilla/firefox/<profile>/chrome/userChrome.css
*/

/*.downloadButton {
    //transform: scale(2.7, 2.7);
    min-width: 90px;
    min-height: 52px;
}*/

#downloadsListBox .downloadButton{
  height: unset !important;
  margin-inline: 0 !important;
  border-radius: 0 !important;
}

#downloadsListBox .downloadButton > .button-box{
  border-left: 1px solid var(--panel-separator-color) !important;
  padding-inline: 18px !important;
}

#downloadsListBox > richlistitem{
  display: flex;
  height: unset !important;
  padding-inline: 0 !important;
  border-radius: 0 !important;
}
#downloadsListBox .downloadMainArea{
  flex-grow: 1;
  padding: 1.2em 0 !important;
}
#downloadsPanel-mainView{
  padding: 0 !important;
}
#downloadsFooterButtons > toolbarseparator{ margin: 0 !important; }

#downloadsFooterButtons > #downloadsHistory:not(:hover){
  background: rgba(120,120,120,0.1) !important;
}