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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: #1a1a1a;
    background: #e8e8e8;
    padding: 0;
}

.exercise-header {
    background: #2a2a2a;
    color: white;
    padding: 20px 30px;
    text-align: center;
    margin-bottom: 30px;
}

.exercise-header h1 {
    font-size: 1.3rem;
    font-weight: 500;
    margin: 0;
}

.exercise-header a {
    color: white;
    text-decoration: underline;
}

main {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px 40px;
}

.card {
    background: #fef6dc;
    border-radius: 8px;
    padding: 30px;
    margin-bottom: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.context-card {
    margin-bottom: 30px;
}

.context-card h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: #333;
}

.section-title {
    background: #2a2a2a;
    color: white;
    font-size: 1.1rem;
    font-weight: 500;
    padding: 12px 20px;
    margin: -30px -30px 20px -30px;
    border-radius: 8px 8px 0 0;
}

.card-content h3 {
    font-size: 1rem;
    font-weight: 600;
    margin: 20px 0 8px 0;
    color: #333;
}

.card-content h3:first-child {
    margin-top: 0;
}

.card-content ul {
    margin-left: 20px;
    margin-bottom: 15px;
}

.card-content li {
    margin-bottom: 5px;
    color: #444;
}

.card-content p {
    color: #444;
}

.solution-link {
    min-height: 100px;
}

.two-column {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

footer {
    max-width: 1400px;
    margin: 40px auto 0;
    padding: 20px;
    text-align: center;
    border-top: 1px solid #ccc;
}

footer p {
    font-size: 0.9rem;
    color: #666;
}

footer a {
    color: #0066cc;
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

@media (max-width: 768px) {
    .exercise-header h1 {
        font-size: 1rem;
    }
    
    .two-column {
        grid-template-columns: 1fr;
    }
    
    .card {
        padding: 20px;
    }
    
    .section-title {
        margin: -20px -20px 15px -20px;
    }
}