:root {
    --bg-color: #f5f7fa;
    --card-bg-color: white;
    --text-color: #1f2937;
    --header-bg-color: #1f2937;
    --header-text-color: white;
    --footer-text-color: #6b7280;
    --shadow-color: rgba(0,0,0,0.1);
}

body.dark-mode {
    --bg-color: #121212;
    --card-bg-color: #1e1e1e;
    --text-color: #e0e0e0;
    --header-bg-color: #1e1e1e;
    --header-text-color: #e0e0e0;
    --footer-text-color: #8c8c8c;
    --shadow-color: rgba(255,255,255,0.1);
}

body {
    font-family: Arial, Helvetica, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    transition: background-color 0.3s, color 0.3s;
}

header {
    background-color: var(--header-bg-color);
    color: var(--header-text-color);
    padding: 20px;
    text-align: center;
    transition: background-color 0.3s, color 0.3s;
}

#theme-toggle {
    background: #4a5568;
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
    margin-top: 10px;
}

#theme-toggle:hover {
    background: #2d3748;
}

section {
    max-width: 800px;
    margin: 40px auto;
    background: var(--card-bg-color);
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 10px var(--shadow-color);
    transition: background-color 0.3s, box-shadow 0.3s;
}

h2 {
    color: var(--text-color);
}

ul {
    line-height: 1.8;
}

footer {
    text-align: center;
    color: var(--footer-text-color);
    margin: 40px 0;
    font-size: 14px;
    transition: color 0.3s;
}

form {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-top: 20px;
}

form label {
    font-weight: bold;
    color: var(--text-color);
}

form input[type="email"],
form textarea {
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
    background-color: var(--card-bg-color);
    color: var(--text-color);
}

form button[type="submit"] {
    background: #1f2937;
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

form button[type="submit"]:hover {
    background: #374151;
}