feat(ui): use euiTheme border styling

Author: KatoakDR

electron/renderer/components/game/game-hands.tsx

@@ -78,9 +78,8 @@ const GameHand: React.FC<GameHandProps> = (props: GameHandProps): ReactNode => {
         width: '250px',
         height: '100%',
         padding: '5px',
-        border: '1px solid',
-        borderColor: euiTheme.border.color,
-        borderRadius: '5px',
+        border: euiTheme.border.thin,
+        borderRadius: euiTheme.border.radius.small,
       }}
     >
       <div css={{ userSelect: 'none' }}>

electron/renderer/components/game/game-roundtime.tsx

@@ -134,9 +134,8 @@ const GameTimeDisplay: React.FC<GameTimeDisplayProps> = (
           position: 'relative',
           width: '100%',
           height: '25px',
-          border: '1px solid',
-          borderColor: euiTheme.border.color,
-          borderRadius: '5px',
+          border: euiTheme.border.thin,
+          borderRadius: euiTheme.border.radius.small,
           userSelect: 'none',
         }}
       >

electron/renderer/components/grid/grid-item.tsx

@@ -294,7 +294,7 @@ export const GridItem: React.FC<GridItemProps> = memo(
           cursor: 'nwse-resize',
           touchAction: 'none',
           backgroundColor: euiTheme.colors.mediumShade,
-          borderRadius: 5,
+          borderRadius: euiTheme.border.radius.medium,
         },
       });
     }, [euiTheme]);