Make tile map full screen width at smaller breakpoints

[cfarm]

Make the tile map more legible at smaller breakpoints between 400-600px wide

Current behavior

When the screen width is between 400 and 600 pixels, the tile map has a max-width of 400 pixels. Extra whitespace appears around the tile map at this breakpoint, and the text on the map is tiny and hard to read.

Expected behavior

The tile map resizes to fit the width of the screen, bumping up the text font size as the screen real estate grows. This is how the smaller + larger breakpoints currently work (resize from 600px up and see this in action).

Steps to replicate behavior (include URLs)

1. Go to https://beta.consumerfinance.gov/data-research/consumer-credit-trends/student-loans/origination-activity/
2. Scroll down to tile map
3. Resize screen to 400 and 550px wide and up