body {
        background: #f6fcff;
        margin: 0;
        padding: 0;
        font-family: "Segoe UI", Arial, sans-serif;
      }
      .container {
        max-width: 450px;
        margin: 38px auto 0 auto;
        background: #fff;
        border-radius: 18px;
        box-shadow: 0 4px 22px #13d2b033;
        padding: 30px 14px 22px 14px;
      }
      .logo {
        display: flex;
        align-items: center;
        justify-content: center;
        font-size: 1.55em;
        color: #13b6a7;
        font-weight: bold;
        gap: 8px;
        margin-bottom: 7px;
      }
      .logo-icon {
        font-size: 1.1em;
      }
      h2 {
        text-align: center;
        margin-bottom: 14px;
        color: #135574;
        font-size: 1.15em;
      }
      .desc {
        color: #357890;
        text-align: center;
        margin-bottom: 22px;
        font-size: 0.73em;
      }
      .input-area,
      .output-area {
        width: 100%;
        height: 120px;
        border: 1.2px solid #cce9ef;
        border-radius: 9px;
        padding: 11px;
        font-size: 0.99em;
        background: #fafdff;
        font-family: "Fira Mono", "Menlo", monospace;
        resize: vertical;
        margin-bottom: 8px;
      }
      .output-area {
        background: #e7f9f3;
      }
      .btn-minify,
      .btn-copy {
        background: #13b6a7;
        color: #fff;
        border: none;
        border-radius: 7px;
        padding: 10px 18px;
        margin: 10px 7px 0 0;
        cursor: pointer;
        font-size: 1.03em;
        transition: background 0.18s;
      }
      .btn-minify:active,
      .btn-copy:active {
        background: #088a78;
      }
      .label {
        font-size: 0.97em;
        color: #167088;
        margin-bottom: 2px;
        margin-top: 8px;
        display: block;
      }
      .info-msg {
        color: #1c9b56;
        font-size: 0.93em;
        margin: 6px 0 10px 0;
        text-align: center;
      }
      .footer {
        color: #789;
        text-align: center;
        font-size: 0.95em;
        margin-top: 24px;
      }
      @media (max-width: 600px) {
        .container {
          max-width: 99vw;
          padding: 9px 2vw 12px 2vw;
        }
        .input-area,
        .output-area {
          height: 76px;
          font-size: 0.97em;
        }
        .btn-minify,
        .btn-copy {
          width: 100%;
          margin: 8px 0 0 0;
        }
      }
      #backBtn {
        position: fixed;
        left: 50%;
        bottom: 32px;
        transform: translateX(-50%);
        background: #13b6a7;
        color: #fff;
        font-weight: 700;
        border: none;
        border-radius: 2rem;
        padding: 0.58em 1.5em;
        box-shadow: 0 4px 16px #13d2b066;
        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: #0e8078;
        transform: translateX(-50%) scale(1.04);
      }
      @media (max-width: 600px) {
        #backBtn {
          bottom: 18px;
          font-size: 0.98em;
          padding: 0.48em 1em;
        }
      }