XSLT In SharePoint 2010

Open site collection | create new Tasks list and input data

Open SharePoint Designer | Lists and Library | click on MicrosoftTechnologyTasks List >> right click All Tasks >> Edit File in Advanced Mode

Click on view >> see on Conditional Formatting

Click Conditional Formatting >> Format Row

Set condition

Then click set Style

Choose your formatting

Save file >> Yes

In right panel, you can see the existing conditions >> you can edit or delete

Here is result

Go back code of AllItems.aspx, you can see the conditions as follows