:root {
    --primary-color: #3a3a5c;
    --secondary-color: #f0f0f5;
    --text-color: #333;
    --border-color: #ddd;
    --low-impact: #4CAF50;
    --medium-impact: #FFC107;
    --high-impact: #F44336;
}

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

body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--secondary-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

h1 {
    margin-bottom: 1rem;
    font-size: 2.5rem;
}

main {
    flex: 1;
    padding: 2rem;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.week-navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 1rem;
    background-color: white;
    padding: 0.5rem;
    border-radius: 5px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    cursor: pointer;
    font-weight: bold;
    border-radius: 3px;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #2a2a4c;
}

#current-week-display {
    font-weight: bold;
    font-size: 1.1rem;
}

footer {
    background-color: var(--primary-color);
    color: white;
    text-align: center;
    padding: 1rem;
    margin-top: auto;
}

@media (max-width: 768px) {
    main {
        padding: 1rem;
    }
    
    h1 {
        font-size: 2rem;
    }
}