Here's a similar formula I have in my application:
Case([Activity Status],
"1 Not Started", "<div style=\"background-color:bisque;width:40\">1 Not Started</div>",
"2 Ready", "<div style=\"background-color:yellow;width:40\">2 Ready</div>",
"2 Active", "<div style=\"background-color:yellow;width:40\">2 Active</div>",
"3 Needs Review", "<div style=\"background-color:orange;width:40\">3 Needs Review</div>",
"3 Open Workflow", "<div style=\"background-color:yellow;width:40\">3 Open Workflow</div>",
"4 On Hold", "<div style=\"background-color:orchid;width:40\">4 On Hold</div>",
"5 Deferred", "<div style=\"background-color:deepskyblue;width:40\">5 Deferred</div>",
"6 Completed", "<div style=\"background-color:Chartreuse;width:40\">6 Completed</div>",
"<Unknown Status>", "<div style=\"background-color:red;width:40\"><Unknown Status></div>"
)
And here's a different one where I use images:
If([IsAssignedToInactiveEmployee?],
"<div><img src=\"
https://images.quickbase.com/si/16/282-user_delete.png\"></div>";,
"<div><img src=\"
https://images.quickbase.com/si/16/280-user_0.png\"></div>";
)