:root {
    --bg-color: #1a1a1a; /* Dark mode background */
    --text-color: #e0e0e0; /* Dark mode text */
    --header-color: #ffffff; /* Dark mode headers */
    --feature-bg: #2c2c2c; /* Dark mode feature cards */
    --feature-shadow: 0 2px 5px rgba(0,0,0,0.3);
    --link-color: #66b0ff; /* Dark mode links */
    --cta-bg: #66b0ff; /* Fallback CTA button background */
    --cta-text: #333; /* Darker text for CTA buttons in dark mode */
    --toggle-bg: #444; /* Slider background */
    --toggle-text: #ffffff; /* Slider knob color */
}

body.light-mode {
    --bg-color: #f4f4f4; /* Light mode background */
    --text-color: #333; /* Light mode text */
    --header-color: #2c3e50; /* Light mode headers */
    --feature-bg: #fff; /* Light mode feature cards */
    --feature-shadow: 0 2px 5px rgba(0,0,0,0.1);
    --link-color: #3498db; /* Light mode links */
    --cta-bg: #3498db; /* Fallback CTA button background */
    --cta-text: #ffffff; /* White text for CTA buttons in light mode */
    --toggle-bg: #ccc; /* Light mode slider background */
    --toggle-text: #333; /* Light mode slider knob color */
}

/* Support light mode for noscript users */
@media (prefers-color-scheme: light) {
    body:not(.light-mode) {
        --bg-color: #f4f4f4;
        --text-color: #333;
        --header-color: #2c3e50;
        --feature-bg: #fff;
        --feature-shadow: 0 2px 5px rgba(0,0,0,0.1);
        --link-color: #3498db;
        --cta-bg: #808080; /* Grayscale for noscript */
        --cta-text: #ffffff; /* White text for noscript */
        --toggle-bg: #ccc;
        --toggle-text: #333;
    }
}

body {
    font-family: Arial, sans-serif;
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    line-height: 1.6;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: background-color 0.3s, color 0.3s;
}

h1, h2, h3 {
    color: var(--header-color);
}

h2 {
    background-color: var(--bg-color); /* Match page background */
    padding: 10px 0;
    margin: 20px 0 10px;
}

.feature {
    background: var(--feature-bg);
    padding: 15px;
    margin: 10px 0;
    border-radius: 5px;
    box-shadow: var(--feature-shadow);
}

a {
    color: var(--link-color);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

.cta {
    margin-top: 20px;
    text-align: center;
}

.cta a {
    background: var(--cta-bg);
    color: var(--cta-text);
    padding: 10px 20px;
    border-radius: 5px;
    margin: 0 10px;
    transition: background 0.3s, color 0.3s;
}

footer {
    margin-top: auto;
    text-align: center;
    padding: 10px 0;
    color: #999;
    font-size: 0.9em;
}

.toggle-container {
    position: fixed;
    top: 20px;
    right: 20px;
}

.theme-slider {
    display: inline-block;
    cursor: pointer;
}

.theme-slider input {
    display: none;
}

.slider {
    display: block;
    width: 40px;
    height: 20px;
    background: var(--toggle-bg);
    border-radius: 20px;
    position: relative;
    transition: background 0.3s;
}

.slider::before {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    background: var(--toggle-text);
    border-radius: 50%;
    top: 2px;
    left: 2px;
    transition: transform 0.3s;
}

.theme-slider input:checked + .slider::before {
    transform: translateX(20px);
}

.theme-slider input:disabled + .slider {
    opacity: 0.5;
    cursor: not-allowed;
}

img, video {
    max-width: 100%;
    border-radius: 5px;
    margin-top: 10px;
    display: block;
}

.video-container {
    margin: 20px 0;
}

.video-container.side-by-side {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.video-container.side-by-side video {
    max-width: 48%;
    flex: 1 1 48%;
}

details {
    margin: 10px 0;
    border-radius: 5px;
    overflow: hidden;
}

summary {
    background: var(--feature-bg);
    color: var(--header-color);
    padding: 10px;
    cursor: pointer;
    font-size: 1.2em;
    font-weight: bold;
    transition: background 0.3s;
}

summary:hover {
    background: var(--link-color);
}

details[open] summary {
    background: var(--link-color);
}