Changing text size of selected words of an image caption

Site URL: https://maroon-marlin-74y3.squarespace.com/

Hello everyone, may I please ask for your assistance!

https://maroon-marlin-74y3.squarespace.com/
Password: Astor1234

I am struggling to find ways in coding an image caption to just decrease the text size of a specific word.
The below image is what I want. I only need to decrease the text size of "KNZM,OBE" but keep the layout exactly the same. 

The current image is set in the "Card" format.

I have attempted the markdown block method but it ruins the layout by reducing the image size and adding a separation between the name + date. 

I hope this makes sense. Please please help!

First, make this text bold

Quote

KNZM,OBE

next, add this to Design > Custom CSS

div#block-c7ef9d3fcab594f4862b .image-title h3 strong {
    font-weight: normal;
    font-size: 10px;
}

Worked perfectly! Thank you so so much!!