Hi nguyenthaodang
When you use the 'Theme Customizer' tool in template. Once the customization is done, save the changes. The changes is not saved directly to the customizer, it is saved as a preset. Open the Preset setting panel and select the version you saved. The preset works like a theme, it contains all the changes you did with the customizer.
You can find the generated files in: /templates/ja_simpli/etc/presets/styles