Fix display first cell on big boards

android/gradle.properties

 org.gradle.jvmargs=-Xmx1536M
 android.useAndroidX=true
 android.enableJetifier=true
-app.versionName=0.0.17
-app.versionCode=17
+app.versionName=0.0.18
+app.versionCode=18

lib/entities/cell.dart

@@ -20,6 +20,8 @@ class Cell {
     );
 
     if ((row == 0) && (col == 0)) {
+      double blackPointFontSize = 30.0 - (myProvider.boardSize);
+
       return Stack(
         alignment: Alignment.center,
         children: <Widget>[
@@ -29,7 +31,7 @@ class Cell {
                 '•',
                 style: TextStyle(
                   color: Colors.black,
-                  fontSize: 30.0,
+                  fontSize: blackPointFontSize,
                   fontWeight: FontWeight.w800,
                 ),
                 textAlign: TextAlign.center