fix: Chrome draws the popup's text at the 14px text-sm declares (closes #456)

Chrome gives extension pages a stylesheet of its own that sets body to
75%, outside any cascade layer, so it beat Tailwind's text-sm and Chrome
drew the popup at 12px where Firefox draws 14px. body now carries
text-sm!, the important form, as it already carries font-mono!. Both
browser suites check that body computes to 14px.

At 14px the recovery phrase instruction on the add wallet screen takes a
third line, which pushed Import below the fold at 360x600. The die button
now shares the instruction's row instead of taking a row of its own.

Model: opus-5-5

tests/e2e/run.js

@@ -113,6 +113,18 @@ test("the popup is drawn in the monospace font it declares (#418)", async (env)
     );
 });
 
+// The same stylesheet sets the size on body to 75%, which would draw the
+// popup at 12px.
+test("the popup's text is drawn at the 14px text-sm declares (#456)", async (env) => {
+    const size = await env.page.evaluate(
+        () => getComputedStyle(document.body).fontSize,
+    );
+    assert(
+        size === "14px",
+        "the popup's text is drawn at " + size + ", not at the 14px of text-sm",
+    );
+});
+
 // The empirical half of #182. The manifest change is only a claim about
 // what the CSP permits; this is the observation. Two things have to hold
 // together, and the run covers both: the popup realm compiles WASM (here),