body {
        background: #f7f9fe;
        margin: 0;
        font-family: "Segoe UI", Arial, sans-serif;
        color: #234;
      }
      .container {
        max-width: 430px;
        margin: 40px auto;
        background: #fff;
        border-radius: 16px;
        box-shadow: 0 4px 20px #2238;
        padding: 30px 20px 18px;
      }
      .logo {
        font-size: 1.21em;
        font-weight: bold;
        text-align: center;
        color: #154185;
        margin-bottom: 10px;
        letter-spacing: 0.02em;
      }
      .desc {
        text-align: center;
        color: #2262b3;
        margin-bottom: 15px;
        font-size: 1.03em;
      }
      .form-row {
        margin-bottom: 14px;
      }
      input[type="text"] {
        padding: 10px 11px;
        border-radius: 7px;
        border: 1.2px solid #bfd8ff;
        font-size: 1.08em;
        width: 100%;
        background: #fafdff;
        color: #234;
        transition: border 0.15s;
        box-sizing: border-box;
      }
      input[type="text"]:focus {
        border-color: #2278d4;
        outline: none;
      }
      .action-btn {
        background: #1875d1;
        color: #fff;
        border: none;
        border-radius: 8px;
        padding: 12px 0;
        width: 100%;
        font-size: 1.13em;
        font-weight: bold;
        cursor: pointer;
        margin-top: 7px;
        margin-bottom: 11px;
        box-shadow: 0 2px 12px #1875d120;
        transition: background 0.15s;
      }
      .action-btn:active {
        background: #0e4775;
      }
      .result-block {
        background: #f4f7fd;
        border: 1.2px solid #bfe1fa;
        border-radius: 9px;
        padding: 18px 11px 13px;
        margin-bottom: 7px;
        color: #194f9e;
        font-size: 1.14em;
        text-align: center;
        word-break: break-all;
      }
      section#faq {
        background: #f0f7fc;
        border-radius: 15px;
        padding: 18px 14px 13px 16px;
        margin: 28px 0 0;
        border: 1px solid #b9daf8;
        font-size: 0.99em;
      }
      section#faq h3 {
        font-weight: bold;
        color: #1875d1;
        margin-bottom: 6px;
        font-size: 1.08em;
        text-align: center;
      }
      section#faq dt {
        color: #195269;
        margin-top: 10px;
        margin-bottom: 2px;
        font-weight: 500;
      }
      section#faq dd {
        color: #265a7a;
        margin-left: 7px;
        margin-bottom: 7px;
      }
      .ipa {
        font-size: 1.35em;
        color: #1974b8;
        background: #e6f4fc;
        border-radius: 6px;
        padding: 5px 12px;
        display: inline-block;
        margin: 8px 0 5px;
        font-family: "Segoe UI", Arial, "Times New Roman", serif;
        letter-spacing: 1px;
      }
      .footer {
        color: #789;
        text-align: center;
        font-size: 0.96em;
        margin-top: 18px;
      }
      #backBtn {
        position: fixed;
        left: 50%;
        bottom: 32px;
        transform: translateX(-50%);
        background: #1875d1;
        color: #fff;
        font-weight: 700;
        border: none;
        border-radius: 2rem;
        padding: 0.58em 1.5em;
        box-shadow: 0 4px 16px #1875d133;
        font-size: 1.09em;
        text-decoration: none;
        cursor: pointer;
        letter-spacing: 0.01em;
        transition: background 0.15s, transform 0.12s;
        z-index: 2000;
      }
      #backBtn:hover {
        background: #0e4775;
        transform: translateX(-50%) scale(1.04);
      }
      @media (max-width: 600px) {
        .container {
          max-width: 99vw;
          padding: 12px 2vw 14px 2vw;
        }
        #backBtn {
          bottom: 18px;
          font-size: 0.98em;
          padding: 0.48em 1em;
        }
      }