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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f4f7f6;
    color: #333;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.main-header {
    background-color: #2c3e50;
    color: #ffffff;
    text-align: center;
    padding: 40px 20px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.main-header h1 {
    font-size: 2.2rem;
    margin-bottom: 10px;
}

.main-header p {
    font-size: 1.1rem;
    color: #bdc3c7;
}

.container {
    flex: 1;
    max-width: 1200px;
    margin: 40px auto;
    padding: 0 20px;
    width: 100%;
}


.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 25px;
}


.exercice-card {
    display: block;
    background-color: #ffffff;
    border-radius: 8px;
    padding: 30px 20px;
    text-align: center;
    text-decoration: none;
    color: #333;
    border: 1px solid #e0e0e0;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}

.exercice-card h2 {
    color: #2980b9;
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.exercice-card p {
    color: #7f8c8d;
    font-size: 1rem;
}


.exercice-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    border-color: #3498db;
}

.main-footer {
    background-color: #2c3e50;
    color: #bdc3c7;
    text-align: center;
    padding: 20px;
    margin-top: auto;
}


@media (max-width: 600px) {
    .main-header {
        padding: 30px 15px;
    }
    .main-header h1 {
        font-size: 1.8rem;
    }
}