add duel background

src/ui/Duel/PlayMat/Bg/index.module.scss

@@ -17,7 +17,7 @@
 .block {
   height: var(--block-height-m);
   width: var(--block-width);
-  background: radial-gradient(#1d1d1d, #222);
+  background: radial-gradient(#ffffff00, #222);
   position: relative;
   &.extra {
     margin-inline: calc(var(--block-width) / 2 + var(--col-gap) / 2);

src/ui/Duel/PlayMat/Mat/index.module.scss

+body {
+  background-image: url(/neos-assets/play-mat.png);
+  background-repeat: no-repeat;
+  background-size: cover;
+}
+
 section.mat {
   position: relative;
   width: "100%";