<!DOCTYPE html>
<html lang="en" data-theme="sepia">
<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <title>Math Practice Drills</title>
  <style>
    :root {
      --bg: #ffffff;
      --fg: #111111;
      --muted: #666666;
      --accent: #2d6cdf;
      --okay: #1f9d55;
      --bad: #d64545;
      --panel: #f6f7f9;
      --focus: #b5cdfc;
      --shadow: rgba(0,0,0,0.06);
      font-size: 18px;
    }
    @media (prefers-color-scheme: dark) {
    