body {
    font-family: 'Inter', sans-serif; 
    background-color: #f0f4f8; 
    transition: background-color 0.3s, color 0.3s;
}
.yale-blue { background-color: #00356b; }
.yale-blue-text { color: #00356b; }
.yale-gray { background-color: #8a8a8a; }
.yale-gray-text { color: #4a4a4a; }
.puzzle-container {
    background-color: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    margin-bottom: 2rem;
    transition: opacity 0.5s ease-in-out, background-color 0.3s, color 0.3s;
}
.hidden { display: none; opacity: 0; }
.visible { display: block; opacity: 1; }
.question-card {
    border: 1px solid #e2e8f0;
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 1rem;
    transition: background-color 0.3s, border-color 0.3s;
}
.option-button {
    display: block;
    width: 100%;
    text-align: left;
    padding: 0.75rem 1rem;
    margin-bottom: 0.5rem;
    border: 1px solid #cbd5e1;
    border-radius: 6px;
    transition: background-color 0.2s, border-color 0.2s, color 0.3s;
}
.option-button:hover {
    background-color: #e2e8f0;
}
.option-button.correct {
    background-color: #c6f6d5; /* Green-200 */
    border-color: #38a169; /* Green-600 */
}
.option-button.incorrect {
    background-color: #fed7d7; /* Red-200 */
    border-color: #c53030; /* Red-600 */
}
.feedback-message {
    padding: 0.5rem;
    border-radius: 4px;
    margin-top: 0.5rem;
    font-weight: bold;
}
.feedback-correct {
    background-color: #c6f6d5;
    color: #2f855a;
}
.feedback-incorrect {
    background-color: #fed7d7;
    color: #9b2c2c;
}
.green-light {
    width: 20px;
    height: 20px;
    background-color: #9ca3af; /* Gray-400 */
    border-radius: 50%;
    display: inline-block;
    margin-right: 8px;
    transition: background-color 0.3s;
}
.green-light.on {
    background-color: #4ade80; /* Green-400 */
}
.tile {
    border: 2px solid #00356b; /* Yale Blue */
    padding: 1rem;
    margin: 0.5rem;
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.2s, background-color 0.2s, color 0.3s;
    min-width: 150px;
    text-align: center;
}
.tile:hover {
    transform: translateY(-3px);
    background-color: #e0e7ff; /* Light blue hover */
}
.tile.selected {
    background-color: #00356b; /* Yale Blue */
    color: white;
    border-color: #002147; /* Darker Yale Blue */
}
.tile.matched {
    background-color: #d1fae5; /* Greenish */
    border-color: #059669;
    cursor: default;
    opacity: 0.7;
}
.drop-zone {
    border: 2px dashed #00356b;
    padding: 1rem;
    margin: 0.5rem;
    border-radius: 8px;
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: border-color 0.3s;
}
.limerick-box {
    background-color: #fffbeb; /* Light yellow */
    border-left: 4px solid #facc15; /* Yellow */
    padding: 1rem;
    margin-bottom: 1rem;
    font-style: italic;
    transition: background-color 0.3s, border-color 0.3s;
}

/* Dark Mode Styles */
.dark-mode {
    color: #e2e8f0;
    background-color: #1a202c;
}

.dark-mode .yale-blue-text {
    color: #4299e1;
}

.dark-mode .yale-gray-text {
    color: #a0aec0;
}

.dark-mode .puzzle-container {
    background-color: #2d3748;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
}

.dark-mode .question-card {
    border-color: #4a5568;
    background-color: #2d3748;
}

.dark-mode .option-button {
    border-color: #4a5568;
    color: #e2e8f0;
    background-color: #2d3748;
}

.dark-mode .option-button:hover {
    background-color: #4a5568;
}

.dark-mode .option-button.correct {
    background-color: #276749;
    border-color: #38a169;
    color: #f0fff4;
}

.dark-mode .option-button.incorrect {
    background-color: #9b2c2c;
    border-color: #c53030;
    color: #fff5f5;
}

.dark-mode .tile {
    border-color: #4299e1;
    background-color: #2d3748;
}

.dark-mode .tile:hover {
    background-color: #2c5282;
    color: #e2e8f0;
}

.dark-mode .tile.selected {
    background-color: #4299e1;
    color: #f7fafc;
    border-color: #2b6cb0;
}

.dark-mode .tile.matched {
    background-color: #276749;
    border-color: #059669;
    color: #f0fff4;
}

.dark-mode .limerick-box {
    background-color: #2a2827;
    border-left: 4px solid #d69e2e;
    color: #e2e8f0;
}

.dark-mode .drop-zone {
    border-color: #4299e1;
}

.dark-mode input[type="text"], 
.dark-mode input[type="radio"] {
    background-color: #2d3748;
    border-color: #4a5568;
    color: #e2e8f0;
}

.dark-mode input[type="text"]::placeholder {
    color: #a0aec0;
}

.dark-mode label {
    background-color: #2d3748;
    border-color: #4a5568;
}

.dark-mode label:hover {
    background-color: #4a5568;
}

.dark-mode .feedback-correct {
    background-color: #276749;
    color: #f0fff4;
}

.dark-mode .feedback-incorrect {
    background-color: #9b2c2c;
    color: #fff5f5;
}

.dark-mode p {
    color: #e2e8f0;
}

.dark-mode h2, .dark-mode h3 {
    color: #4299e1;
}

/* Toggle Button Styles */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    background-color: #00356b;
    color: white;
    border: none;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 999;
    transition: background-color 0.3s;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.dark-mode .theme-toggle {
    background-color: #4299e1;
}