:root {
    --background-color: #f0f0f0;
    --text-color: #333;
    --card-background: #fff;
    --border-color: #ddd;
    --button-background: #333;
    --button-text-color: #fff;
}

body.dark-mode {
    --background-color: #333;
    --text-color: #f0f0f0;
    --card-background: #444;
    --border-color: #555;
    --button-background: #f0f0f0;
    --button-text-color: #333;
}

body {
    background-color: var(--background-color);
    color: var(--text-color);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    transition: background-color 0.3s, color 0.3s;
    margin: 0;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

#theme-toggle {
    background-color: var(--button-background);
    color: var(--button-text-color);
    border: none;
    padding: 10px 20px;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s, color 0.3s;
}

h1, h2 {
    margin: 0;
}

.weather-card, .air-quality-card, .forecast-container {
    background-color: var(--card-background);
    padding: 20px;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    margin-top: 10px;
}

.forecast-container {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.forecast-day {
    flex: 1 1 100px;
    text-align: center;
    padding: 10px;
    border-radius: 5px;
    background-color: var(--background-color);
}