:root {
      --primary-color: #005bac;
      --secondary-color: #2a7ab0;
      --bg-color: #f4f7fa;
      --card-bg-color: #ffffff;
      --text-color: #333333;
      --muted-color: #6c757d;
      --border-color: #dee2e6;
      --success-color: #28a745;
      --error-color: #dc3545;
      --font-family: 'Segoe UI', 'Roboto', 'Helvetica', 'Arial', sans-serif;
    }
    html {
      height: 100%;
    }
    body {
      margin: 0;
      padding: 0;
      background-color: var(--bg-color);
      color: var(--text-color);
      font-family: var(--font-family);
      line-height: 1.6;
      display: flex;
      flex-direction: column;
      min-height: 100vh;
    }
    .header {
      display: flex;
      align-items: center;
      justify-content: center;
      padding: 1.5rem 1rem;
      border-bottom: 1px solid var(--border-color);
      background-color: #fff;
    }
    .header-logo {
      height: 60px;
      width: auto;
    }
    .header-text {
      margin-left: 1.5rem;
      padding-left: 1.5rem;
      border-left: 1px solid var(--border-color);
    }
    .header h1 {
      font-size: 1.8rem;
      font-weight: 400;
      margin: 0;
      color: var(--text-color);
    }
    .header p {
      font-size: 1rem;
      color: var(--muted-color);
      margin: 0.25rem 0 0;
    }
    .container {
      max-width: 700px;
      margin: 2.5rem auto;
      padding: 0 1rem;
      flex: 1 0 auto;
    }
    .container-title {
      text-align: center;
      margin-bottom: 1.5rem;
      font-size: 1.7rem;
      font-weight: 600;
      color: var(--text-color);
    }
    .card {
      background-color: var(--card-bg-color);
      border-radius: 12px;
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
      padding: 2.5rem;
      transition: all 0.3s ease;
    }
    .upload-area {
      border: 2px dashed var(--border-color);
      border-radius: 12px;
      padding: 2.5rem;
      text-align: center;
      cursor: pointer;
      transition: border-color 0.3s, background-color 0.3s;
    }
    .upload-area:hover, .upload-area.drag-over {
      border-color: var(--primary-color);
      background-color: #f8f9fa;
    }
    .upload-area .icon {
      width: 50px;
      height: 50px;
      color: var(--primary-color);
      margin-bottom: 1rem;
    }
    .upload-area-text {
      font-size: 1.1rem;
      font-weight: 500;
    }
    .upload-area-subtext {
      color: var(--muted-color);
      font-size: 0.9rem;
    }
    #file {
      display: none;
    }
    .file-info {
      display: none;
      margin-top: 1.5rem;
      padding: 1rem;
      background-color: #e9f5ff;
      border-left: 4px solid var(--primary-color);
      border-radius: 4px;
      font-weight: 500;
    }
    .options {
      margin-top: 2rem;
      display: grid;
      grid-template-columns: 1fr;
      gap: 1.5rem;
    }
    @media (min-width: 576px) {
      .options {
        grid-template-columns: 1fr 1fr;
      }
    }
    label {
      display: block;
      margin-bottom: 0.5rem;
      font-weight: 500;
      color: var(--muted-color);
    }
    select, input[type="text"] {
      width: 100%;
      padding: 0.75rem 1rem;
      border-radius: 8px;
      border: 1px solid var(--border-color);
      background-color: #fff;
      color: var(--text-color);
      font-size: 1rem;
      box-sizing: border-box;
    }
    button#btn {
      width: 100%;
      padding: 0.85rem 1rem;
      border-radius: 8px;
      border: none;
      background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
      color: #fff;
      font-size: 1.1rem;
      font-weight: 600;
      cursor: pointer;
      margin-top: 2rem;
      transition: transform 0.2s, box-shadow 0.3s;
      box-shadow: 0 4px 15px rgba(0, 91, 172, 0.25);
    }
    button#btn:hover {
      transform: translateY(-2px);
      box-shadow: 0 6px 20px rgba(0, 91, 172, 0.35);
    }
    button#btn:disabled {
      opacity: 0.6;
      cursor: not-allowed;
      transform: none;
      box-shadow: 0 4px 15px rgba(0, 91, 172, 0.25);
    }
    a#dl {
      display: none;
      width: 100%;
      box-sizing: border-box;
      text-align: center;
      padding: 0.85rem 1rem;
      border-radius: 8px;
      background-color: var(--success-color);
      color: #fff;
      font-size: 1.1rem;
      font-weight: 600;
      text-decoration: none;
      margin-top: 1rem;
      transition: background-color 0.3s;
    }
    a#dl:hover {
      background-color: #218838;
    }
    .footer {
      text-align: center;
      margin-top: 2.5rem;
      font-size: 0.9rem;
      color: var(--muted-color);
    }

    /* From Uiverse.io by Nawsome */ 
    .loader {
      --background: linear-gradient(135deg, #23C4F8, #275EFE);
      --shadow: rgba(39, 94, 254, 0.28);
      --text: #6C7486;
      --page: rgba(255, 255, 255, 0.36);
      --page-fold: rgba(255, 255, 255, 0.52);
      --duration: 3s;
      width: 200px;
      height: 140px;
      position: relative;
      margin: 2.5rem auto;
    }

    .loader:before, .loader:after {
      --r: -6deg;
      content: "";
      position: absolute;
      bottom: 8px;
      width: 120px;
      top: 80%;
      box-shadow: 0 16px 12px var(--shadow);
      transform: rotate(var(--r));
    }

    .loader:before {
      left: 4px;
    }

    .loader:after {
      --r: 6deg;
      right: 4px;
    }

    .loader div {
      width: 100%;
      height: 100%;
      border-radius: 13px;
      position: relative;
      z-index: 1;
      perspective: 600px;
      box-shadow: 0 4px 6px var(--shadow);
      background-image: var(--background);
    }

    .loader div ul {
      margin: 0;
      padding: 0;
      list-style: none;
      position: relative;
    }

    .loader div ul li {
      --r: 180deg;
      --o: 0;
      --c: var(--page);
      position: absolute;
      top: 10px;
      left: 10px;
      transform-origin: 100% 50%;
      color: var(--c);
      opacity: var(--o);
      transform: rotateY(var(--r));
      -webkit-animation: var(--duration) ease infinite;
      animation: var(--duration) ease infinite;
    }

    .loader div ul li:nth-child(2) {
      --c: var(--page-fold);
      -webkit-animation-name: page-2;
      animation-name: page-2;
    }

    .loader div ul li:nth-child(3) {
      --c: var(--page-fold);
      -webkit-animation-name: page-3;
      animation-name: page-3;
    }

    .loader div ul li:nth-child(4) {
      --c: var(--page-fold);
      -webkit-animation-name: page-4;
      animation-name: page-4;
    }

    .loader div ul li:nth-child(5) {
      --c: var(--page-fold);
      -webkit-animation-name: page-5;
      animation-name: page-5;
    }

    .loader div ul li svg {
      width: 90px;
      height: 120px;
      display: block;
    }

    .loader div ul li:first-child {
      --r: 0deg;
      --o: 1;
    }

    .loader div ul li:last-child {
      --o: 1;
    }

    .loader span {
      display: block;
      left: 0;
      right: 0;
      top: 100%;
      margin-top: 20px;
      text-align: center;
      color: var(--text);
    }

    @keyframes page-2 {
      0% {
        transform: rotateY(180deg);
        opacity: 0;
      }

      20% {
        opacity: 1;
      }

      35%, 100% {
        opacity: 0;
      }

      50%, 100% {
        transform: rotateY(0deg);
      }
    }

    @keyframes page-3 {
      15% {
        transform: rotateY(180deg);
        opacity: 0;
      }

      35% {
        opacity: 1;
      }

      50%, 100% {
        opacity: 0;
      }

      65%, 100% {
        transform: rotateY(0deg);
      }
    }

    @keyframes page-4 {
      30% {
        transform: rotateY(180deg);
        opacity: 0;
      }

      50% {
        opacity: 1;
      }

      65%, 100% {
        opacity: 0;
      }

      80%, 100% {
        transform: rotateY(0deg);
      }
    }

    @keyframes page-5 {
      45% {
        transform: rotateY(180deg);
        opacity: 0;
      }

      65% {
        opacity: 1;
      }

      80%, 100% {
        opacity: 0;
      }

      95%, 100% {
        transform: rotateY(0deg);
      }
    }