I'm trying to create a grid with three columns, but if there are fewer than three items in a given row, I want the items to span the width of the grid. I'm including a screenshot of my current layout, an edit showing what I would like, and snippets of my HTML and CSS:
Current Layout (Note: the title at the top is done with a separate grid than the one with pictures. If there is a better way to do this, any help would be appreciated.):

Desired Layout:

HTML:
Botanicals
CSS:
#grid-title{
display: grid;
grid-template-columns: auto;
border: 1px solid black;
background-color: var(--navbarbg);
text-align: center;
}
#grid-body{
display: grid;
grid-template-columns: 1fr 1fr 1fr;
text-align: center;
}
#grid-item{
justify-content: center;
border: 1px solid black;
}




