update doc css

docs/source/_static/css/custom.css

@@ -1,3 +1,4 @@
+/* top left logo */
 .wy-side-nav-search, .wy-nav-top {
     background: linear-gradient(15deg, #13547a 0%, #80d0c7 100%);
 }
@@ -23,12 +24,17 @@
   color: #4b827c;
 }
 
-
-
+/* class object */
 .sig.sig-object {
-    padding: 5px 5px 5px 5px;
+    padding: 5px 5px 5px 8px;
     background-color: #e6e6e6;
     border-style: solid;
     border-color: black;
     border-width: 1px 0;
 }
+
+/* parameter object */
+dt {
+    padding: 5px 5px 5px 8px;
+    background-color: #ebebeb;
+}