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/firefox/run.js

@@ -128,6 +128,18 @@ step("the popup is drawn in the monospace font it declares", async (env) => {
     );
 });
 
+// The same check as the Chrome suite's (#456), so both browsers are held to
+// the same size.
+step("the popup's text is drawn at the 14px text-sm declares", async (env) => {
+    const size = await env.driver.execute(
+        "return getComputedStyle(document.body).fontSize;",
+    );
+    assert(
+        size === "14px",
+        "the popup's text is drawn at " + size + ", not at the 14px of text-sm",
+    );
+});
+
 // The recovery screen (#361): the Chrome suite's four cases, run before any
 // wallet exists for the same reason. With no wallet nothing saves on a timer,
 // so no save can write a good record over the unreadable one. The last of them