I found that the following code worked but it deleted all the categories.
#geodir_map_v3_home_map_1_cat{display: none;}
What I want to do is to minimize the list as below.
<AS IS>
1. Restaurant
– Chinese
– Korean
2. Shop
– Supermarket
– Department store
<TO BE>*Click [+] to open children categories .
1. Restaurant [+]
2. Shop [+]
How can I make it happen?