/* General Styles */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #0A192F; /* Deep Blue Background */
    color: #E0E0E0; /* Light Gray/Off-White Text */
    line-height: 1.6;
}

.container {
    width: 80%;
    margin: 0 auto;
    padding: 20px 0;
    max-width: 1200px;
}

h1, h2, h3 {
    color: #FFFFFF; /* White headings */
}

h1 {
    font-size: 2.8em;
    margin-bottom: 0.2em;
}

h2 {
    font-size: 2em;
    margin-bottom: 0.5em;
}

h3 {
    font-size: 1.5em;
    color: #00BFFF; /* Bright Electric Blue for sub-subheadings */
}

p {
    margin-bottom: 1em;
}

ul {
    list-style: none;
    padding-left: 0;
}

ul li {
    padding-left: 1.5em;
    position: relative;
    margin-bottom: 0.5em;
}

ul li::before {
    content: '»'; /* Using a chevron as a bullet point */
    position: absolute;
    left: 0;
    color: #00BFFF; /* Bright Electric Blue for bullets */
    font-weight: bold;
}

a {
    color: #00BFFF; /* Bright Electric Blue for links */
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* Header */
header {
    background: linear-gradient(rgba(10, 25, 47, 0.85), rgba(17, 45, 82, 0.9)), url('ai-background.png'); /* AI-themed background with gradient overlay */
    background-color: #0A192F; /* Fallback color */
    background-size: cover;
    background-position: center;
    color: #FFFFFF;
    padding: 40px 0 30px; /* Reduced padding */
    text-align: center;
    border-bottom: 3px solid #007BFF; /* Slightly thinner border */
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2); /* Adjusted shadow */
}

header h1 {
    font-weight: 700;
    letter-spacing: 1px;
    font-size: 2.5em; /* Reduced font size */
    margin-bottom: 0.2em;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.3);
}

header h2 {
    font-size: 1.3em; /* Reduced font size */
    font-weight: 300;
    color: #C0D6F0;
    margin-bottom: 0.5em; /* Reduced margin */
    letter-spacing: 0.3px;
}

header .author {
    font-size: 1.1em; /* Reduced font size */
    font-style: normal;
    color: #A9CCE3;
    font-weight: 400; /* Slightly lighter weight */
}

/* Main Content Sections */
main section {
    padding: 40px 0;
}

main section:nth-child(even) {
    background-color: #0F2340; /* Slightly lighter blue for alternating sections */
}

/* Book Details Section */
#book-details .container {
    display: flex;
    flex-wrap: wrap;
    gap: 40px;
    align-items: flex-start;
}

#book-details .book-cover {
    flex: 1;
    min-width: 250px;
    max-width: 350px; /* Control max size of cover */
}

#book-details .book-cover img {
    width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
}

#book-details .description {
    flex: 2;
    min-width: 300px;
}

/* Buy Links Section */
#buy-links {
    text-align: center;
}

#buy-links .buttons {
    margin-top: 20px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 15px;
}

.btn {
    display: inline-block;
    background-color: #00BFFF; /* Bright Electric Blue */
    color: #FFFFFF; /* White text */
    padding: 12px 25px;
    border-radius: 5px;
    font-size: 1.1em;
    font-weight: bold;
    text-transform: uppercase;
    transition: background-color 0.3s ease, transform 0.2s ease;
    box-shadow: 0 4px 8px rgba(0, 191, 255, 0.2);
}

.btn:hover {
    background-color: #009ACD; /* Darker shade of blue on hover */
    text-decoration: none;
    transform: translateY(-2px);
}

/* Footer */
footer {
    background-color: #08142B; /* Darker blue for footer */
    color: #A0A0A0;
    text-align: center;
    padding: 20px 0;
    border-top: 1px solid #0F2340;
    font-size: 0.9em;
}

/* Modal Styles */
.modal {
    display: none; /* Hidden by default */
    position: fixed; /* Stay in place */
    z-index: 1; /* Sit on top */
    left: 0;
    top: 0;
    width: 100%; /* Full width */
    height: 100%; /* Full height */
    overflow: auto; /* Enable scroll if needed */
    background-color: rgb(0,0,0); /* Fallback color */
    background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
}

.modal-content {
    background: linear-gradient(rgba(10, 25, 47, 0.85), rgba(17, 45, 82, 0.9)), url('ai-background.png');
    background-color: #0A192F; /* Fallback color */
    background-size: cover;
    background-position: center;
    margin: 15% auto; /* 15% from the top and centered */
    padding: 20px;
    border: 1px solid #888;
    width: 80%; /* Could be more or less, depending on screen size */
    max-width: 500px;
    text-align: center;
    border-radius: 8px;
    box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2),0 6px 20px 0 rgba(0,0,0,0.19);
}

.modal-content p {
    color: #FFFFFF;
    font-weight: bold;
    font-size: 1.2em;
}

.close-button {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
}

.close-button:hover,
.close-button:focus {
    color: white;
    text-decoration: none;
    cursor: pointer;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        width: 90%;
    }

    header h1 {
        font-size: 2.2em;
    }

    header h2 {
        font-size: 1.3em;
    }

    #book-details .container {
        flex-direction: column;
        align-items: center;
    }

    #book-details .book-cover {
        margin-bottom: 30px;
        max-width: 300px; /* Adjust for smaller screens */
    }

    .btn {
        padding: 10px 20px;
        font-size: 1em;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.8em;
    }

    header h2 {
        font-size: 1.1em;
    }

    h2 { /* Section titles */
        font-size: 1.6em;
    }

    h3 {
        font-size: 1.3em;
    }

    #buy-links .buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 80%;
        max-width: 300px;
        margin-bottom: 10px;
    }
}