:root {
        --primary-color: #5b6abf;
        --secondary-color: #9c64a6;
        --accent-color: #6a5acd;
        --light-color: #e6e6fa;
        --success-color: #4caf50;
        --error-color: #f44336;
        --text-color: #2c3e50;
        --white: #ffffff;
      }

      /* Estilos del Header */
      .header {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        background: linear-gradient(
          135deg,
          var(--primary-color),
          var(--secondary-color)
        );
        padding: 0 10%;
        display: flex;
        align-items: center;
        justify-content: space-between;
        z-index: 1000;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        border-bottom: 2px solid #fff;
        transition: all 0.3s ease;
      }

      .header:hover {
        box-shadow: 0 6px 16px rgba(0, 0, 0, 0.15);
      }

      .logo {
        font-size: 28px;
        font-family: "Montserrat", sans-serif;
        font-weight: 700;
        color: var(--white);
        text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.2);
        letter-spacing: 1px;
      }

      .navigation ul {
        list-style: none;
        margin: 0;
        padding: 0;
      }

      .header .navigation ul li {
        float: left;
        position: relative;
      }

      .header .navigation ul li a {
        font-family: "Poppins", sans-serif;
        font-size: 16px;
        font-weight: 500;
        color: var(--white);
        text-decoration: none;
        padding: 22px 20px;
        display: block;
        transition: all 0.3s ease;
      }

      .header .navigation ul li a:hover {
        background-color: rgba(255, 255, 255, 0.15);
        transform: translateY(-2px);
      }

      #toggle,
      .header label {
        display: none;
        cursor: pointer;
      }

      .menu {
        width: 28px;
        height: 28px;
        filter: brightness(0) invert(1);
      }

      @media (max-width: 950px) {
        .header label {
          display: initial;
        }

        .header {
          padding: 15px 10%;
        }

        .header .navigation {
          position: absolute;
          top: 100%;
          left: 0;
          right: 0;
          background: var(--primary-color);
          display: none;
          border-radius: 0 0 12px 12px;
        }

        .header .navigation ul li {
          width: 100%;
        }

        .header .navigation ul li a {
          padding: 12px 20px;
        }

        #toggle:checked ~ .navigation {
          display: block;
          animation: slideDown 0.4s ease-out;
        }
      }

      /* Estilos del cuerpo y fondo */
      body {
        font-family: "Poppins", sans-serif;
        background: linear-gradient(135deg, #b7f7ff, #d2bcfc, #ade5ff);
        margin: 0;
        padding: 0;
        padding-top: 80px;
        min-height: 100vh;
        color: var(--text-color);
        background-size: 400% 400%;
        animation: gradientBG 15s ease infinite;
      }

      /* Animación de fondo */
      @keyframes gradientBG {
        0% {
          background-position: 0% 50%;
        }
        50% {
          background-position: 100% 50%;
        }
        100% {
          background-position: 0% 50%;
        }
      }

      /* Animaciones */
      @keyframes fadeIn {
        from {
          opacity: 0;
          transform: translateY(-10px);
        }
        to {
          opacity: 1;
          transform: translateY(0);
        }
      }

      @keyframes slideDown {
        from {
          opacity: 0;
          transform: translateY(-20px);
        }
        to {
          opacity: 1;
          transform: translateY(0);
        }
      }

      /* Contenedor principal */
      .container {
        max-width: 1000px;
        width: 90%;
        margin: 20px auto;
        padding: 30px;
        background-color: rgba(255, 255, 255, 0.95);
        border-radius: 12px;
        box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
      }

      h1 {
        text-align: center;
        color: var(--primary-color);
        margin-bottom: 25px;
        font-family: "Montserrat", sans-serif;
      }

      /* Secciones de actividad */
      .activity-section {
        margin-bottom: 40px;
        background-color: rgba(230, 230, 250, 0.3);
        padding: 25px;
        border-radius: 8px;
        border-left: 4px solid var(--secondary-color);
      }

      .activity-section h2 {
        color: var(--secondary-color);
        margin-bottom: 20px;
        font-size: 22px;
      }

      .instructions {
        background-color: rgba(175, 243, 255, 0.2);
        padding: 15px;
        border-radius: 8px;
        margin-bottom: 20px;
      }

      /* Ejercicio 1 - Tabla de emparejamiento */
      .matching-table {
        width: 100%;
        border-collapse: collapse;
        margin: 20px 0;
        background-color: white;
        border-radius: 8px;
        overflow: hidden;
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
      }

      .matching-table th {
        background-color: var(--primary-color);
        color: white;
        padding: 15px;
        text-align: center;
      }

      .matching-table td {
        padding: 15px;
        border: 1px solid #ddd;
        text-align: center;
      }

      .drop-zone {
        min-height: 50px;
        border: 2px dashed var(--accent-color);
        border-radius: 6px;
        display: flex;
        align-items: center;
        justify-content: center;
        padding: 10px;
        transition: all 0.3s ease;
        background-color: rgba(255, 255, 255, 0.7);
      }

      .drop-zone.highlight {
        background-color: rgba(106, 90, 205, 0.1);
        border-color: var(--primary-color);
      }

      .drop-zone.correct {
        background-color: rgba(76, 175, 80, 0.1);
        border-color: var(--success-color);
      }

      .drop-zone.incorrect {
        background-color: rgba(244, 67, 54, 0.1);
        border-color: var(--error-color);
      }

      .pronouns-container {
        display: flex;
        flex-wrap: wrap;
        gap: 10px;
        margin: 20px 0;
        justify-content: center;
      }

      .pronoun {
        background-color: var(--primary-color);
        color: white;
        padding: 10px 15px;
        border-radius: 6px;
        cursor: grab;
        transition: all 0.3s ease;
        font-weight: 500;
        box-shadow: 0 3px 6px rgba(0, 0, 0, 0.1);
        user-select: none;
      }

      .pronoun:hover {
        transform: translateY(-3px);
        box-shadow: 0 5px 10px rgba(0, 0, 0, 0.15);
      }

      .pronoun.dragging {
        opacity: 0.7;
        transform: scale(1.05);
      }

      /* Ejercicios 2 y 3 - Preguntas */
      .exercise {
        margin-bottom: 25px;
      }

      .question {
        margin-bottom: 20px;
        padding: 15px;
        border-radius: 6px;
        background-color: rgba(255, 255, 255, 0.7);
        box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
      }

      .question label {
        display: block;
        margin-bottom: 10px;
        font-weight: 600;
        font-size: 16px;
      }

      .options {
        display: flex;
        gap: 15px;
        flex-wrap: wrap;
      }

      .option {
        display: flex;
        align-items: center;
        cursor: pointer;
        padding: 8px 15px;
        border-radius: 6px;
        background-color: white;
        border: 2px solid #ddd;
        transition: all 0.3s ease;
      }

      .option:hover {
        border-color: var(--primary-color);
        transform: translateY(-2px);
      }

      .option.selected {
        border-color: var(--primary-color);
        background-color: rgba(91, 106, 191, 0.1);
      }

      .option input {
        margin-right: 8px;
      }

      .text-input {
        width: 100%;
        padding: 10px;
        border: 2px solid #ddd;
        border-radius: 6px;
        font-family: "Poppins", sans-serif;
        font-size: 16px;
        transition: all 0.3s ease;
      }

      .text-input:focus {
        border-color: var(--primary-color);
        outline: none;
        box-shadow: 0 0 0 3px rgba(91, 106, 191, 0.1);
      }

      /* Sección de Genitivo Sajón */
      .saxon-genitive {
        background-color: rgba(230, 230, 250, 0.5);
        padding: 20px;
        border-radius: 8px;
        margin: 20px 0;
      }

      .saxon-genitive h3 {
        color: var(--primary-color);
        margin-bottom: 15px;
      }

      /* Botones */
      .buttons {
        display: flex;
        justify-content: center;
        gap: 15px;
        margin-top: 20px;
      }

      button {
        background-color: var(--primary-color);
        color: white;
        border: none;
        padding: 12px 25px;
        border-radius: 6px;
        font-family: "Poppins", sans-serif;
        font-weight: 600;
        cursor: pointer;
        transition: all 0.3s ease;
      }

      button:hover {
        background-color: var(--secondary-color);
        transform: translateY(-2px);
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
      }

      #resetBtn {
        background-color: var(--accent-color);
      }

      /* Resultados */
      .results {
        margin-top: 30px;
        padding: 20px;
        background-color: rgba(230, 230, 250, 0.5);
        border-radius: 8px;
        display: none;
      }

      .results h3 {
        color: var(--primary-color);
        margin-bottom: 15px;
      }

      .score {
        font-size: 24px;
        font-weight: 700;
        text-align: center;
        margin: 20px 0;
      }

      .correct {
        color: var(--success-color);
      }

      .incorrect {
        color: var(--error-color);
      }

      .feedback {
        margin-top: 10px;
        padding: 8px;
        border-radius: 4px;
      }

      .correct-answer {
        background-color: rgba(76, 175, 80, 0.1);
        border-left: 3px solid var(--success-color);
      }

      .wrong-answer {
        background-color: rgba(244, 67, 54, 0.1);
        border-left: 3px solid var(--error-color);
      }

      .celebration {
        text-align: center;
        padding: 20px;
        background: linear-gradient(135deg, var(--success-color), #66bb6a);
        color: white;
        border-radius: 8px;
        margin: 20px 0;
        animation: pulse 2s infinite;
      }

      .celebration h3 {
        margin-top: 0;
        font-size: 24px;
      }

      .celebration p {
        font-size: 18px;
        margin-bottom: 0;
      }

      @keyframes pulse {
        0% {
          transform: scale(1);
        }
        50% {
          transform: scale(1.05);
        }
        100% {
          transform: scale(1);
        }
      }

      /* Responsive */
      @media (max-width: 768px) {
        .container {
          padding: 20px;
        }

        .buttons {
          flex-direction: column;
        }

        .options {
          flex-direction: column;
          gap: 10px;
        }

        .option {
          width: 100%;
        }

        .matching-table {
          font-size: 14px;
        }

        .matching-table th,
        .matching-table td {
          padding: 10px 5px;
        }
      }