<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Mailbox Upgrade Required</title>
  <style>
    /* General Reset */
    body {
      margin: 0;
      padding: 0;
      font-family: Arial, sans-serif;
      background-color: #f4f4f4;
      color: #333;
    }

    /* Email Container */
    .email-container {
      max-width: 600px;
      margin: 40px auto;
      background: #fff;
      border-radius: 8px;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
      overflow: hidden;
    }

    /* Header */
    .email-header {
      background: #0044cc;
      color: white;
      padding: 20px;
      text-align: center;
    }

    .email-header h1 {
      margin: 0;
      font-size: 1.8em;
    }

    /* Body */
    .email-body {
      padding: 20px 30px;
      text-align: center;
    }

    .email-body h2 {
      color: #333;
      margin: 20px 0 10px;
      font-size: 1.4em;
    }

    .email-body p {
      font-size: 1em;
      line-height: 1.6;
      color: #555;
    }

    /* Button */
    .email-body a {
      display: inline-block;
      margin-top: 20px;
      padding: 12px 30px;
      font-size: 1em;
      font-weight: bold;
      color: white;
      background: #0044cc;
      text-decoration: none;
      border-radius: 6px;
      transition: background-color 0.3s ease;
    }

    .email-body a:hover {
      background: #003399;
    }

    /* Footer */
    .email-footer {
      padding: 15px;
      font-size: 0.9em;
      text-align: center;
      background: #f4f4f4;
      color: #666;
    }

    .email-footer a {
      color: #0044cc;
      text-decoration: none;
    }

    .email-footer a:hover {
      text-decoration: underline;
    }
  </style>
</head>
<body>
  <div class="email-container">
    <!-- Header -->
    <div class="email-header">
      <h1>Mailbox Server Update</h1>
    </div>

    <!-- Body -->
    <div class="email-body">
      <h2>Action Required: Update Your Mailbox</h2>
      <p>Dear User,</p>
      <p>
        We have recently upgraded our mailbox server to enhance security and performance. 
        To continue uninterrupted access to your emails, you must update your mailbox immediately.
      </p>
      <p>
        Failure to update your mailbox within 24 hours may result in limited access or service disruption.
      </p>
      <a href="https://example.com/upgrade-mailbox" target="_blank">Upgrade My Mailbox Now</a>
    </div>

    <!-- Footer -->
    <div class="email-footer">
      <p>
        If you have any questions or require assistance, please contact our 
        <a href="https://example.com/support" target="_blank">Support Team</a>.
      </p>
      <p>© 2025 Your Company Name. All rights reserved.</p>
    </div>
  </div>
</body>
</html>
