I don't believe there's a way to add code to the Data & Analysis tab. The JavaScript is on a question-by-question basis and the CSS is limited to the Survey Platform, to my knowledge. I love the idea though! You could post it on Qualtrics' Products and Ideas forum; it's a feature I could see use for, for sure.

I may have spoken too soon.. I was looking into a different question on the Developer Corner and I realized you could add in a new branch with a condition that looks at the Embedded Data 'Progress' and checks if it equals or is less than 2. You could then add an End of Survey element to the branch. On the End of Survey element, click 'customize', choose 'overwrite the default', then the last option is "Don't record this response". You might try that solution, not sure if the branching logic will fire when the survey is closed after a week, but worth a try! Any questions, just ask.

I couldn't make this work. The responses were recorded.
The field progress already exists in the data, and can be viewed in data and analysis once the responses have been recorded. HOWEVEVER, the issue is you CANNOT filter on this field . Ideally, on dashboard settings, progress percent would be defined (e.g., include progress percent greater than or equal to 25). At a minimum. This field (progress) should be available in data and analysis tab so that criteria could be applied. This would at least allow us to apply criteria for who is included