:root {
      --bg-color: #f0f6fa;
      --card-color: rgba(255, 255, 255, 0.9);
      --primary: #1e3a5f;
      --accent: #3498db;
      --shadow: rgba(0, 0, 0, 0.1);
    }
    * {
      box-sizing: border-box;
      transition: all 0.3s ease-in-out;
    }
    body {
      margin: 0;
      padding: 0;
      font-size: 18px;
      font-family: "Times New Roman", serif;
      background: linear-gradient(to right, #d7e9f7, #eaf4fb);
      color: var(--primary);
      margin: 0;
      padding: 0;
      line-height: 1.6;
    }
    header {
      background: var(--primary);
      color: white;
      padding: 1.5rem 2rem;
      text-align: center;
      font-size: 2rem;
      font-weight: bold;
      letter-spacing: 2px;
    }
    .container {
      max-width: 1000px;
      margin: 2rem auto;
      padding: 1rem 2rem;
    }
    .card {
      background-color: var(--card-color);
      border-radius: 16px;
      box-shadow: 0 8px 20px var(--shadow);
      padding: 2rem;
      margin-bottom: 2rem;

      transition: transform 0.3s ease-in-out, box-shadow 0.3s ease-in-out;
    }
    .card:hover {
      transform: scale(1.05);
      box-shadow: 0 12px 30px rgba(30, 58, 95, 0.3);
      cursor: pointer;
    }
    h1, h2, h3 {
      font-family: "Times New Roman", serif;
      color: var(--primary);
      margin-top: 0;
    }
    .button {
      padding: 12px 28px;
      background-color: var(--accent);
      color: white;
      border: none;
      border-radius: 12px;
      cursor: pointer;
      font-weight: 700;
      font-size: 1rem;
      letter-spacing: 1px;
      transition: background-color 0.3s ease;
      display: inline-block;
      margin-top: 10px;
      text-decoration: none;
      text-align: center;
    }
    .button:hover {
      background-color: #2c80b4;
    }
    select {
      width: 100%;
      padding: 10px;
      border-radius: 10px;
      border: 1px solid #ccc;
      margin-top: 1rem;
      font-size: 1rem;
      font-family: "Times New Roman", serif;
    }
    .result {
      margin-top: 1.2rem;
      background: #e1ecf7;
      border-radius: 12px;
      padding: 1rem 1.5rem;
      box-shadow: inset 0 0 8px #a8c6f7;
      line-height: 1.5;
    }
    a {
      color: var(--accent);
      text-decoration: none;
    }
    a:hover {
      text-decoration: underline;
    }
    .box {
      display: none;
      margin-top: 1rem;
      background: #eaf4fb;
      border-radius: 12px;
      padding: 1rem 1.5rem;
      box-shadow: inset 0 0 6px #b5d1f9;
    }