body {
    background-color: #f8f9fa;
    min-height: 100vh;
}

.card {
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    border: none;
}

.btn-primary {
    background-color: #007bff;
    border-color: #007bff;
}

.btn-primary:hover {
    background-color: #0056b3;
    border-color: #0056b3;
}

.mistake-card {
    transition: transform 0.2s;
}

.mistake-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
}

.difficulty-1 {
    border-left: 4px solid #28a745;
}

.difficulty-2 {
    border-left: 4px solid #ffc107;
}

.difficulty-3 {
    border-left: 4px solid #dc3545;
}

.mastery-to-review {
    background-color: #fff3cd;
}

.mastery-mastered {
    background-color: #d4edda;
}

.chat-container {
    max-height: 400px;
    overflow-y: auto;
}

.chat-message {
    margin-bottom: 1rem;
}

.chat-message.user {
    text-align: right;
}

.chat-message.ai {
    text-align: left;
}

.chat-bubble {
    display: inline-block;
    padding: 0.75rem 1rem;
    border-radius: 1rem;
    max-width: 80%;
}

.chat-bubble.user {
    background-color: #007bff;
    color: white;
    border-bottom-right-radius: 0.25rem;
}

.chat-bubble.ai {
    background-color: #e9ecef;
    color: #212529;
    border-bottom-left-radius: 0.25rem;
}