fix legend dark color

utils.py

@@ -60,6 +60,7 @@ template = """
     margin-bottom: 5px;
     font-weight: bold;
     font-size: 90%;
+    color: #333;
     }
   .maplegend .legend-scale ul {
     margin: 0;
@@ -74,6 +75,7 @@ template = """
     margin-left: 0;
     line-height: 18px;
     margin-bottom: 2px;
+    color: #111;
     }
   .maplegend ul.legend-labels li span {
     display: block;