Initial commit

index.css

@@ -0,0 +1,24 @@
+.app {
+    text-align: center;
+}
+
+.big-cell {
+    border: 1px black solid;
+    display: inline-block;
+}
+
+.cell {
+    border: 1px gray solid;
+    width: 20pt;
+    height: 100%;
+    display: inline-block;
+    text-align: center;
+}
+
+.cell-highlight {
+    color: red;
+}
+
+span.cell:empty:before {
+  content: "\200b"; /* unicode zero width space character */
+}