* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #66bb6a 0%, #43a047 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    overflow-x: hidden;
}

.container {
    background: white;
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    max-width: 1000px;
    width: 100%;
    position: relative;
}

h1 {
    color: #333;
    text-align: center;
    margin-bottom: 25px;
    font-size: 32px;
}

/* Story Box */
.story-box {
    background: linear-gradient(135deg, #f1f8e9 0%, #dcedc8 100%);
    border-left: 5px solid #558b2f;
    padding: 25px;
    border-radius: 10px;
    margin-bottom: 30px;
}

.story-header {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.icon {
    font-size: 50px;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.header-text strong {
    color: #33691e;
    font-size: 20px;
    display: block;
}

.header-text p {
    color: #666;
    font-size: 14px;
    margin-top: 3px;
}

.story-text {
    color: #333;
    line-height: 1.8;
    font-size: 18px;
    text-align: center;
}

/* Tree Section */
.tree-section {
    margin: 40px 0;
    display: flex;
    justify-content: center;
}

.tree-container {
    background: linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 100%);
    border: 3px solid #4caf50;
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.tree-img {
    width: 100%;
    max-width: 600px;
    height: auto;
    display: block;
    border-radius: 10px;
}

/* Info Section */
.info-section {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    margin: 30px 0;
}

.info-box {
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
    border: 3px solid #1976d2;
    border-radius: 15px;
    padding: 20px;
}

.info-label {
    font-size: 18px;
    font-weight: bold;
    color: #0d47a1;
    margin-bottom: 12px;
    padding-bottom: 10px;
    border-bottom: 2px solid #1976d2;
}

.info-content {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.info-item {
    font-size: 16px;
    color: #333;
}

.value {
    color: #d84315;
    font-weight: bold;
    font-size: 18px;
}

.formula-text {
    font-family: 'Courier New', monospace;
    font-size: 16px;
    color: #1565c0;
    font-weight: bold;
}

/* Question Section */
.question-section {
    margin: 30px 0;
}

.question-label {
    font-size: 20px;
    font-weight: bold;
    color: #333;
    text-align: center;
    margin-bottom: 15px;
    padding: 20px;
    background: linear-gradient(135deg, #f3e5f5 0%, #e1bee7 100%);
    border-radius: 10px;
    border-left: 5px solid #9c27b0;
}

.question-text {
    font-size: 18px;
    color: #555;
    text-align: center;
    margin-bottom: 25px;
}

/* Drop Zone */
.drop-zone {
    min-height: 100px;
    border: 4px dashed #1976d2;
    border-radius: 15px;
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 30px auto;
    padding: 20px;
    transition: all 0.3s ease;
    position: relative;
}

.drop-zone.drag-over {
    border-color: #0d47a1;
    background: linear-gradient(135deg, #bbdefb 0%, #90caf9 100%);
    transform: scale(1.02);
}

.drop-zone.correct {
    animation: blink-green 0.6s ease 3;
}

.drop-zone.incorrect {
    animation: blink-red 0.6s ease 3;
}

@keyframes blink-green {
    0%, 100% {
        background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
        border-color: #1976d2;
    }
    50% {
        background: linear-gradient(135deg, #c8e6c9 0%, #a5d6a7 100%);
        border-color: #4caf50;
    }
}

@keyframes blink-red {
    0%, 100% {
        background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
        border-color: #1976d2;
    }
    50% {
        background: linear-gradient(135deg, #ffcdd2 0%, #ef9a9a 100%);
        border-color: #f44336;
    }
}

.drop-placeholder {
    font-size: 20px;
    color: #757575;
    font-weight: bold;
}

.dropped-answer {
    font-size: 24px;
    color: #1976d2;
    font-weight: bold;
    display: none;
}

.drop-zone.has-answer .drop-placeholder {
    display: none;
}

.drop-zone.has-answer .dropped-answer {
    display: block;
}

/* Options Container */
.options-container {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    justify-content: center;
    margin: 30px 0;
    padding: 20px;
    background: linear-gradient(135deg, #fff9c4 0%, #fff59d 100%);
    border-radius: 15px;
    border: 3px solid #f57f17;
}

.option-card {
    background: white;
    border: 3px solid #ffa726;
    border-radius: 12px;
    padding: 20px 30px;
    font-size: 20px;
    font-weight: bold;
    color: #333;
    cursor: grab;
    transition: all 0.3s ease;
    user-select: none;
}

.option-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 15px rgba(255, 167, 38, 0.4);
    border-color: #f57c00;
}

.option-card:active {
    cursor: grabbing;
}

.option-card.dragging {
    opacity: 0.5;
    transform: scale(0.95);
}

.option-card.hidden {
    display: none;
}

/* Feedback */
.feedback {
    text-align: center;
    font-size: 20px;
    font-weight: bold;
    min-height: 30px;
    margin-top: 20px;
    padding: 15px;
    border-radius: 10px;
}

.feedback.success {
    color: #4caf50;
    background: linear-gradient(135deg, #c8e6c9 0%, #a5d6a7 100%);
}

.feedback.error {
    color: #f44336;
    background: linear-gradient(135deg, #ffcdd2 0%, #ef9a9a 100%);
}

/* Reset Button */
.reset-btn {
    display: block;
    margin: 20px auto;
    background: #ff9800;
    color: white;
    border: none;
    padding: 15px 40px;
    border-radius: 10px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
}

.reset-btn:hover {
    background: #f57c00;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(255, 152, 0, 0.4);
}

.reset-btn:active {
    transform: translateY(0);
}

/* Responsive */
@media (max-width: 968px) {
    .info-section {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .container {
        padding: 25px;
    }

    h1 {
        font-size: 26px;
    }

    .tree-img {
        max-width: 450px;
    }

    .question-label {
        font-size: 18px;
    }

    .option-card {
        font-size: 18px;
        padding: 15px 25px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 20px;
    }

    h1 {
        font-size: 22px;
    }

    .story-text {
        font-size: 16px;
    }

    .tree-img {
        max-width: 350px;
    }

    .question-label {
        font-size: 16px;
    }

    .option-card {
        font-size: 16px;
        padding: 12px 20px;
    }

    .feedback {
        font-size: 18px;
    }
}