body {
      font-family: 'Arial', sans-serif;
      background-color: #f9f9f9;
      color: #333;
    }
    .container {
      max-width: 800px;
      margin: 0 auto;
      padding: 20px;
      background-color: #fff;
      border-radius: 10px;
      box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    }
    h1 {
      color: #4154cc;
      text-align: center;
      font-size: 2.5rem;
    }
    .converter {
      display: flex;
      flex-direction: column;
      gap: 20px;
      margin-top: 30px;
    }
    .input-group {
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .input-group label {
      font-size: 1.1rem;
      color: #555;
    }
    .input-group input,
    .input-group select {
      padding: 10px;
      border: 2px solid #4154cc;
      border-radius: 5px;
      font-size: 1rem;
    }
    .result {
      margin-top: 20px;
      font-size: 1.2rem;
      color: #4154cc;
      text-align: center;
    }
    .sidebar {
      background-color: #7b9682;
      color: #fff;
      padding: 20px;
      border-radius: 10px;
      margin-top: 30px;
    }
    .footer {
      text-align: center;
      margin-top: 30px;
      padding: 20px;
      background-color: #4154cc;
      color: #fff;
      border-radius: 10px;
    }
    .footer a {
      color: #fff;
      text-decoration: none;
    }
    .footer a:hover {
      text-decoration: underline;
    }
    .header-menu {
      display: flex;
      justify-content: center;
      gap: 20px;
      margin-bottom: 20px;
    }
    .header-menu a {
      color: #4154cc;
      text-decoration: none;
      font-size: 1.1rem;
    }
    .header-menu a:hover {
      text-decoration: underline;
    }
    .advertisement {
      background-color: #4154cc;
      color: #fff;
      padding: 20px;
      border-radius: 10px;
      text-align: center;
      margin: 20px 0;
    }
    .article {
      margin-top: 30px;
      line-height: 1.6;
    }
    .article h2 {
      color: #4154cc;
      font-size: 1.8rem;
    }
    .article p {
      margin-bottom: 20px;
    }
    @media (max-width: 768px) {
      h1 {
        font-size: 2rem;
      }
      .converter {
        gap: 15px;
      }
      .header-menu {
        flex-direction: column;
        align-items: center;
        gap: 10px;
      }
    }