Dark Mode

Code

/* CSS variable definition */
:root {
    --bg: #ffffff;
    --text: #1a1a1a;
    --card-bg: #f5f5f5;
    --border: #e0e0e0;
    --primary: #3498db;
}

/* System dark mode */
@media (prefers-color-scheme: dark) {
    :root {
        --bg: #1a1a1a;
        --text: #f0f0f0;
        --card-bg: #2a2a2a;
        --border: #404040;
        --primary: #5dade2;
    }
}

/* Manual switch */
[data-theme="dark"] {
    --bg: #1a1a1a;
    --text: #f0f0f0;
    --card-bg: #2a2a2a;
    --border: #404040;
    --primary: #5dade2;
}

/* Apply variables */
body {
    background-color: var(--bg);
    color: var(--text);
    transition: background-color 0.3s, color 0.3s;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border);
}

/* JS toggle */
/*
const toggle = document.getElementById('theme-toggle');
toggle.addEventListener('click', () => {
    const current = document.documentElement.getAttribute('data-theme');
    document.documentElement.setAttribute(
        'data-theme', current === 'dark' ? 'light' : 'dark'
    );
});
*/

Explanation

Implements dark mode via CSS variables and the data-theme attribute; prefers-color-scheme follows the system.

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