Apologies if this is a stale thread but just wanted to share this with anyone interested.
I created a GitHub repo that contains some CSS snippets to accompany the Todoist sync plugin that makes the tasks in Obsidian look more like Todoist tasks.
Here’s the repo:
obsidian-todoist-plugin-styles
Disclaimer: While I am quite knowledgeable with CSS I do hold my hands up and say it could be implemented a lot more efficiently 
I’ve taken the colors directly from Todoist so if nothing else you can copy those 