在ExtJS Classic 7.3.0中创建动画棋盘。需要帮助删除复选标记周围的容器边框

Ext.application({
    name: 'ChessBoardApp',
    launch: function () {
        Ext.create('Ext.container.Container', {
            renderTo: Ext.getBody(),
            layout: 'fit',
            items: [{
                xtype: 'container',
                layout: 'grid',
                columns: 8,
                defaults: {
                    xtype: 'component',
                    width: 50,
                    height: 50,
                    style: {
                        border: '1px solid black'
                    },
                    listeners: {
                        click: function () {
                            // 处理点击事件
                        }
                    }
                },
                items: [{
                    html: 'A1'
                }, {
                    html: 'A2'
                }, {
                    html: 'A3'
                }, {
                    html: 'A4'
                }, {
                    html: 'A5'
                }, {
                    html: 'A6'
                }, {
                    html: 'A7'
                }, {
                    html: 'A8'
                }, {
                    html: 'B1'
                }, {
                    html: 'B2'
                }, {
                    html: 'B3'
                }, {
                    html: 'B4'
                }, {
                    html: 'B5'
                }, {
                    html: 'B6'
                }, {
                    html: 'B7'
                }, {
                    html: 'B8'
                }, {
                    html: 'C1'
                }, {
                    html: 'C2'
                }, {
                    html: 'C3'
                }, {
                    html: 'C4'
                }, {
                    html: 'C5'
                }, {
                    html: 'C6'
                }, {
                    html: 'C7'
                }, {
                    html: 'C8'
                }, {
                    html: 'D1'
                }, {
                    html: 'D2'
                }, {
                    html: 'D3'
                }, {
                    html: 'D4'
                }, {
                    html: 'D5'
                }, {
                    html: 'D6'
                }, {
                    html: 'D7'
                }, {
                    html: 'D8'
                }, {
                    html: 'E1'
                }, {
                    html: 'E2'
                }, {
                    html: 'E3'
                }, {
                    html: 'E4'
                }, {
                    html: 'E5'
                }, {
                    html: 'E6'
                }, {
                    html: 'E7'
                }, {
                    html: 'E8'
                }, {
                    html: 'F1'
                }, {
                    html: 'F2'
                }, {
                    html: 'F3'
                }, {
                    html: 'F4'
                }, {
                    html: 'F5'
                }, {
                    html: 'F6'
                }, {
                    html: 'F7'
                }, {
                    html: 'F8'
                }, {
                    html: 'G1'
                }, {
                    html: 'G2'
                }, {
                    html: 'G3'
                }, {
                    html: 'G4'
                }, {
                    html: 'G5'
                }, {
                    html: 'G6'
                }, {
                    html: 'G7'
                }, {
                    html: 'G8'
                }, {
                    html: 'H1'
                }, {
                    html: 'H2'
                }, {
                    html: 'H3'
                }, {
                    html: 'H4'
                }, {
                    html: 'H5'
                }, {
                    html: 'H6'
                }, {
                    html: 'H7'
                }, {
                    html: 'H8'
                }]
            }]
        });
    }
});