improve bond graphical primitives

src/styles/pdb-ligand-env-svg.css

@@ -29,16 +29,19 @@
 
 .pdb-lig-env-svg-bond-stacking {
     stroke-width: 2px;
+    stroke-dasharray: 10 10;
     stroke: green;
 }
 
 .pdb-lig-env-svg-bond-atom-pi {
     stroke-width: 2px;
+    stroke-dasharray: 10 10;
     stroke: #2E8B57;
 }
 
 .pdb-lig-env-svg-bond-amide {
     stroke-width: 2px;
+    stroke-dasharray: 10 10;
     stroke: green;
 }
 
@@ -65,16 +68,18 @@
 
 .pdb-lig-env-svg-bond-clashes {
     stroke-width: 2px;
+    stroke-dasharray: 10 10;
     stroke: #FF5050;
 }
 
 .pdb-lig-env-svg-bond-covalent {
-    stroke-width: 2px;
+    stroke-width: 3px;
     stroke: black;
 }
 
 .pdb-lig-env-svg-bond-other {
     stroke-width: 1px;
+    stroke-dasharray: 10 10;
     stroke: black;
 }