Alter the height of the logo:

.et_fixed_nav #logo {
max-height: 160px;
}

Adjust the shrinking size:

.et-fixed-header #logo {
  max-height: 90px !important;
 padding:0 !important;	 
}

Change the speed of the shrink:

#logo {
transition: all 0.4s ease-in-out;
}

Alter the spacing at the top:
#logo {
	position: relative;
	top:-18px;
}

Alter the overhang at the bottom:

#logo {
	position: absolute;
	top:-18px;
}

Scale logo for mobile:

#logo {
  max-width: 30%;
  min-width:150px;
}