Core has a rule that increases specifically the house icon:

You can overwrite it like:
.d-header .discourse-tags .d-icon-house {
font-size: var(--font-0);
}
Core has a rule that increases specifically the house icon:

You can overwrite it like:
.d-header .discourse-tags .d-icon-house {
font-size: var(--font-0);
}