refactor(docs-infra): clean up styles in `_card.scss` (#40427)

This commit cleans up the styles in `_card.scss` by:
- Fixing incosistenct indentation/newlines.
- Removing rules for unused selectors.
- Removing unnecessary styles.

PR Close #40427

aio/src/styles/2-modules/_card.scss

@@ -19,20 +19,11 @@
     }
 
     &:hover {
-        text-decoration: none;
-
       section {
         color: $blue;
       }
 
-        p {
-          color: $darkgray;
-          padding: 0 16px;
-        }
-
       .card-footer {
-          @include line-height(32);
-          padding: 8px 16px;
         background-color: rgba($blue, 0.1);
         color: $blue;
       }
@@ -73,10 +64,6 @@
         @include font-size(13);
       }
     }
-
-      .card-footer.center {
-        text-align: center;
-      }
   }
 }
 
@@ -107,5 +94,4 @@
   button {
     text-align: center;
   }
-
 }