When the project is closed, different subtasks will be displayed in different colors on the project. If the subtasks are overdue, they will be marked with red overdue font

Gantt
#1

Hello, I have a requirement that when the project is closed, different subtasks will be displayed in different colors on the project. If the subtasks are overdue, they will be marked with red overdue font. I hope to receive your help. Thank you very much

#2

Hello,
To display several tasks on the same row, you need to use the Split Tasks feature:
https://docs.dhtmlx.com/gantt/desktop__split_tasks.html

You will also need to enable the open_split_tasks config to display child tasks on the same row when the parent task is collapsed and display the child tasks as usual when the parent task is expanded:
https://docs.dhtmlx.com/gantt/api__gantt_open_split_tasks_config.html

Starting from the 8.0 version, you can add different styles to the child tasks that are rendered on the same row:
https://docs.dhtmlx.com/gantt/desktop__split_tasks.html#styling

Here is an example:

If you want to add several styles, you can add a variable with the string or array type and add the class names to that variable depending on the conditions. At the end, you can return all those strings in the task_class template. Then, you can use these class names as selectors and add the style rules you need.
Here is an example of how it can be implemented:
https://snippet.dhtmlx.com/7e2icl15