Custom stylesheet fixes (#687)

Signed-off-by: Christian Biasuzzi <christian.biasuzzi@soft.it>

Author: CBiasuzzi

network-area-diagram/src/main/resources/customStyle.css

@@ -1,8 +1,8 @@
-.nad-branch-edges .nad-edge-path, .nad-3wt-edges .nad-edge-path {stroke: grey; stroke-width: 5; fill: none}
-.nad-branch-edges .nad-winding, .nad-3wt-nodes .nad-winding {stroke: grey; stroke-width: 5; fill: none}
+.nad-branch-edges .nad-edge-path, .nad-3wt-edges .nad-edge-path {stroke: var(--nad-vl-color, grey); stroke-width: 5; fill: none}
+.nad-branch-edges .nad-winding, .nad-3wt-nodes .nad-winding {stroke: var(--nad-vl-color, grey); stroke-width: 5; fill: none}
 .nad-text-edges {stroke: black; stroke-width: 3; stroke-dasharray: 6,7}
-.nad-vl-nodes .nad-busnode {fill: lightgrey}
-.nad-vl-nodes circle.nad-unknown-busnode {stroke: #808080; stroke-width: 5; stroke-dasharray: 5,5; fill: none}
+.nad-vl-nodes .nad-busnode {fill: var(--nad-vl-color, lightgrey)}
+.nad-vl-nodes circle.nad-unknown-busnode {stroke: var(--nad-vl-color, #808080); stroke-width: 5; stroke-dasharray: 5,5; fill: none}
 .nad-hvdc-edge polyline.nad-hvdc {stroke: grey; stroke-width: 40}
 .nad-branch-edges .nad-tie-line-edge .nad-edge-path {stroke-width: 7}
 .nad-pst-arrow {stroke: #6a6a6a; stroke-width: 4; stroke-linecap: round; fill: none}
@@ -12,5 +12,5 @@ path.nad-arrow-in:not(.nad-state-in .nad-arrow-in) {visibility: hidden}
 .nad-text-nodes {font: 25px serif; fill: black; dominant-baseline: central}
 .nad-text-nodes foreignObject {overflow: visible; color: black}
 .nad-label-box {background-color: #6c6c6c20; width: max-content; padding: 10px; border-radius: 10px;}
-.nad-legend-square {width: 20px; height: 20px; background: lightgrey;}
+.nad-legend-square {width: 20px; height: 20px; background: var(--nad-vl-color, lightgrey);}
 .nad-edge-infos text, .nad-edge-label text {font: 20px serif; dominant-baseline:middle; stroke: #FFFFFFAA; stroke-width: 10; stroke-linejoin:round; paint-order: stroke}