body {
    margin: 0;
    overflow: hidden; /* Hide scrollbars */
    background-color: #000; /* Black background */
    font-family: sans-serif;
}

canvas {
    display: block;
    position: fixed; /* Keep canvas behind nav */
    top: 0;
    left: 0;
    z-index: -1; /* Ensure nav is on top */
}

#pageNav {
    position: fixed;
    top: 10px;
    left: 10px;
    z-index: 10;
    background-color: rgba(255, 255, 255, 0.1);
    padding: 10px;
    border-radius: 5px;
}

#pageNav a {
    color: #fff;
    text-decoration: none;
    margin-right: 15px;
    padding: 5px 10px;
    border-radius: 3px;
    transition: background-color 0.3s ease;
}

#pageNav a:hover,
#pageNav a.active {
    background-color: rgba(255, 255, 255, 0.3);
}

#pageNav a:last-child {
    margin-right: 0;
}

#page4Container {
    width: 100vw;
    height: 100vh;
    overflow-y: scroll;
    overflow-x: hidden;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 5; /* Below nav, but potentially above a subdued canvas */
    scroll-behavior: smooth; /* Enable smooth scrolling between sections if anchors are used */
    background-color: #1a1a1a; /* Default dark background for page 4 */
}

.historySection {
    min-height: 100vh; /* Each section takes at least the full viewport height */
    padding: 50px;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    color: #f0f0f0;
    opacity: 0; /* Hidden by default, revealed by JS on scroll */
    transform: translateY(50px); /* Start slightly offset for transition */
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
    position: relative; /* For potential pseudo-elements or absolutely positioned details */
}

.historySection.visible {
    opacity: 1;
    transform: translateY(0);
}

.historySection h2 {
    font-size: 3em;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.historySection p {
    font-size: 1.2em;
    max-width: 700px;
    line-height: 1.6;
    position: relative; /* Ensure text is above canvas if overlapping */
    z-index: 2;
}

.historySection .historyTextContent {
    position: relative; /* To allow z-indexing if needed */
    z-index: 2; 
    background-color: rgba(0,0,0,0.3); /* Slight dark background for text readability */
    padding: 20px;
    border-radius: 8px;
    max-width: 80%;
}

.historyCanvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%; /* Will be controlled by JS or specific CSS for each section */
    z-index: 1; /* Behind text content */
    /* --canvas-height variable can be used here if set by JS */
    /* height: var(--canvas-height, 100%); */
}

/* --- Specific Era Styling Examples (to be expanded) --- */
#primordial {
    background: linear-gradient(to bottom, #2c3e50, #1a252f);
}

#ancientCivilizations {
    background: linear-gradient(to bottom, #b29a68, #8c734a);
    color: #333;
}
#ancientCivilizations h2 {
    color: #4a3b29;
}

#digitalAge {
    background: linear-gradient(to bottom, #0f0f23, #0a0a15);
    color: #00ffea;
}
#digitalAge h2 {
    font-family: 'Courier New', Courier, monospace;
    text-shadow: 0 0 5px #00ffea, 0 0 10px #00ffea;
}
#digitalAge p {
    font-family: 'Lucida Console', Monaco, monospace;
}

#headerImage {
    width: 100%;
    max-height: 200px; /* Adjust as needed */
    object-fit: cover; /* Crop image to fit, or use 'contain' */
    display: block; /* Remove extra space below image */
}