:root {
    --background-light: #f8f9fa;
    --background-dark: #121212;
    --text-light: #333;
    --text-dark: #e0e0e0;
    --primary-light: #0056b3;
    --primary-dark: #1ea7fd;
    --secondary-light: #0073e6;
    --secondary-dark: #81d4fa;
    --tertiary-light: #003366;
    --tertiary-dark: #42a5f5;
}

body {
    font-family: 'Arial', sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--background-light);
    color: var(--text-light);
    transition: background-color 0.3s, color 0.3s;
}

.container {
    width: 80%;
    margin: 50px auto;
    background: #fff;
    padding: 40px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    border-radius: 8px;
    transition: background-color 0.3s, color 0.3s;
}

header {
    text-align: center;
    margin-bottom: 40px;
}

h1 {
    color: var(--primary-light);
    font-size: 2.5em;
    margin-bottom: 10px;
}

h2 {
    color: var(--secondary-light);
    margin-top: 40px;
    border-bottom: 2px solid #ddd;
    padding-bottom: 10px;
    font-size: 1.75em;
}

h3 {
    color: var(--tertiary-light);
    margin-top: 20px;
    font-size: 1.5em;
}

ul {
    margin-left: 20px;
    list-style-type: disc;
    padding-left: 10px;
}

p {
    line-height: 1.6;
    font-size: 1em;
}

strong {
    font-weight: bold;
    color: var(--primary-light);
}

section {
    margin-bottom: 30px;
}

@media (prefers-color-scheme: dark) {
    body {
        background-color: var(--background-dark);
        color: var(--text-dark);
    }

    .container {
        background: #1e1e1e;
        color: var(--text-dark);
    }

    h1 {
        color: var(--primary-dark);
    }

    h2 {
        color: var(--secondary-dark);
    }

    h3 {
        color: var(--tertiary-dark);
    }

    strong {
        color: var(--primary-dark);
    }
}

@media (max-width: 768px) {
    .container {
        width: 90%;
        padding: 20px;
    }

    h1 {
        font-size: 2em;
    }

    h2 {
        font-size: 1.5em;
    }

    h3 {
        font-size: 1.25em;
    }

    p {
        font-size: 0.9em;
    }
}