:root {
        --primary-color: #77dd77;
        --secondary-color: #a8e6cf;
        --accent-color: #dcedc1;
        --light-color: #e8f5e9;
        --text-color: #2e7d32;
        --white: #ffffff;
        --incorrect-color: #ff6b6b;
      }

      * {
        font-family: "Poppins", sans-serif;
        box-sizing: border-box;
      }

      /* Header Styles */
      .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-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-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, 0.733);
        transform: translateY(-2px);
        color: var(--text-color);
      }

      #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;
        }
      }

      body {
        background: linear-gradient(135deg, #e8f5e9, #c8e6c9, #a5d6a7);
        margin: 0;
        padding: 20px;
        min-height: 100vh;
        padding-top: 80px;
        color: var(--text-color);
        display: flex;
        flex-direction: column;
        align-items: center;
      }

      .game-container {
        background-color: rgba(255, 255, 255, 0.9);
        border-radius: 15px;
        box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
        padding: 30px;
        width: 90%;
        max-width: 800px;
        margin: 20px 0;
      }

      h1 {
        color: var(--text-color);
        text-align: center;
        margin-bottom: 20px;
        font-weight: 600;
      }

      .section {
        background-color: var(--light-color);
        padding: 20px;
        border-radius: 10px;
        margin-bottom: 30px;
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.05);
      }

      .section-title {
        font-size: 20px;
        color: var(--text-color);
        margin-bottom: 15px;
        font-weight: 600;
        border-bottom: 2px solid var(--accent-color);
        padding-bottom: 5px;
      }

      .instructions {
        margin-bottom: 15px;
        font-weight: 500;
      }

      .drag-drop-container {
        display: flex;
        flex-direction: column;
        gap: 15px;
      }

      .items-container {
        display: flex;
        justify-content: space-between;
        gap: 15px;
      }

      .drag-items,
      .drop-zones {
        flex: 1;
        display: flex;
        flex-direction: column;
        gap: 10px;
      }

      .drag-item {
        padding: 12px;
        background-color: var(--primary-color);
        color: white;
        border-radius: 8px;
        cursor: grab;
        box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
        transition: all 0.2s;
        user-select: none;
        text-align: center;
      }

      .drag-item:active {
        cursor: grabbing;
      }

      .drag-item.dragging {
        opacity: 0.5;
      }

      .drop-zone {
        padding: 12px;
        background-color: var(--accent-color);
        border-radius: 8px;
        min-height: 50px;
        display: flex;
        align-items: center;
        justify-content: center;
        text-align: center;
        transition: all 0.2s;
        border: 2px dashed var(--text-color);
      }

      .drop-zone.highlight {
        background-color: var(--secondary-color);
        transform: scale(1.02);
      }

      .drop-zone.correct {
        border-color: #2e7d32;
        background-color: #c8e6c9;
      }

      .drop-zone.incorrect {
        border-color: var(--incorrect-color);
        background-color: #ffcdd2;
        animation: shake 0.5s;
      }

      @keyframes shake {
        0%,
        100% {
          transform: translateX(0);
        }
        20%,
        60% {
          transform: translateX(-5px);
        }
        40%,
        80% {
          transform: translateX(5px);
        }
      }

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

      .btn {
        background-color: var(--primary-color);
        color: white;
        border: none;
        padding: 12px 25px;
        border-radius: 30px;
        font-size: 16px;
        cursor: pointer;
        transition: all 0.3s;
        font-weight: 600;
      }

      .btn:hover {
        background-color: #66bb6a;
        transform: translateY(-3px);
        box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
      }

      .btn-check {
        background-color: #42a5f5;
      }

      .btn-check:hover {
        background-color: #1e88e5;
      }

      .results {
        margin-top: 30px;
        padding: 20px;
        border-radius: 10px;
        background-color: var(--light-color);
        text-align: center;
      }

      .progress-bar {
        width: 100%;
        height: 30px;
        background-color: #e0e0e0;
        border-radius: 15px;
        margin: 15px 0;
        overflow: hidden;
      }

      .progress {
        height: 100%;
        background: linear-gradient(
          90deg,
          var(--primary-color),
          var(--secondary-color)
        );
        border-radius: 15px;
        transition: width 0.5s ease;
        display: flex;
        align-items: center;
        justify-content: center;
        color: white;
        font-weight: bold;
      }

      .feedback {
        margin-top: 15px;
        font-size: 16px;
        font-weight: 500;
      }

      .feedback.correct {
        color: #2e7d32;
      }

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

      .congratulations {
        animation: pulse 1.5s infinite;
        font-size: 24px;
        color: #2e7d32;
        margin-top: 15px;
      }

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

      .locked {
        pointer-events: none;
      }

      .matched-pair {
        background-color: #bbdefb;
        border: 2px solid #64b5f6;
      }