<style>
:root {
    /* Light theme (default) */
    --bg-color: #f7f7f7;
    --text-color: #333;
    --card-bg: #fff;
    --primary-color: #007BFF;
    --shadow: rgba(0, 0, 0, 0.1);
}

/* 🌌 Dark Neon Theme */
body.dark-mode {
    --bg-color: #0a0a0a;
    --text-color: #e0e0e0;
    --card-bg: #141414;
    --primary-color: #00f5ff;
    --shadow: rgba(0, 255, 255, 0.2);
}

/* Global body fade and color transition */
body {
    background: var(--bg-color);
    color: var(--text-color);
    font-family: Arial, sans-serif;
    margin: 0;
    transition: background 0.8s ease, color 0.8s ease;
    animation: fadeIn 1s ease-in-out;
}

/* Neon-glow fade animation */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Card styling */
.card {
    background: var(--card-bg);
    box-shadow: 0 2px 10px var(--shadow);
    border-radius: 10px;
    padding: 20px;
    margin: 20px auto;
    max-width: 700px;
    transition: background 0.8s ease, box-shadow 0.8s ease, transform 0.3s ease;
    animation: cardEnter 0.7s ease-out;
}

/* Subtle card entrance animation */
@keyframes cardEnter {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Simple neon glow effect for dark mode */
body.dark-mode h1, 
body.dark-mode h2, 
body.dark-mode a {
    text-shadow: 0 0 8px var(--primary-color), 0 0 20px var(--primary-color);
}

/* Links and hover glow */
a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s, text-shadow 0.3s;
}

a:hover {
    text-shadow: 0 0 5px var(--primary-color), 0 0 10px var(--primary-color);
}

/* Toggle button styling */
.theme-toggle {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 50%;
    width: 45px;
    height: 45px;
    cursor: pointer;
    font-size: 20px;
    box-shadow: 0 0 10px var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    z-index: 1000;
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: 0 0 20px var(--primary-color), 0 0 40px var(--primary-color);
}

/* Smooth transition for buttons and cards */
button, .card, a {
    transition: all 0.3s ease;
}
</style>
