body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #333;
    min-height: 100vh;
    transition: background 0.3s, color 0.3s;
}

body.dark {
    background: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
    color: #ecf0f1;
}

header {
    background-color: rgba(76, 175, 80, 0.9);
    color: white;
    text-align: center;
    padding: 2em 1em;
    box-shadow: 0 2px 10px rgba(0,0,0,0.2);
    transition: background-color 0.3s;
}

body.dark header {
    background-color: rgba(52, 73, 94, 0.9);
}

nav ul {
    list-style-type: none;
    padding: 0;
    text-align: center;
    margin: 1em 0;
}

nav ul li {
    display: inline-block;
    margin: 0 1em;
    background-color: rgba(255,255,255,0.1);
    border-radius: 20px;
    transition: background-color 0.3s;
}

nav ul li:hover {
    background-color: rgba(255,255,255,0.2);
}

body.dark nav ul li {
    background-color: rgba(0,0,0,0.1);
}

body.dark nav ul li:hover {
    background-color: rgba(0,0,0,0.2);
}

nav ul li a {
    text-decoration: none;
    color: white;
    font-weight: bold;
    padding: 10px 20px;
    display: block;
}

footer {
    text-align: center;
    padding: 1em;
    background-color: rgba(0,0,0,0.1);
    color: white;
    position: fixed;
    bottom: 0;
    width: 100%;
    transition: background-color 0.3s;
}

body.dark footer {
    background-color: rgba(0,0,0,0.3);
}

.game-container {
    max-width: 800px;
    margin: 2em auto 5em;
    padding: 2em;
    background-color: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    animation: fadeIn 0.5s ease-in;
    transition: background-color 0.3s, color 0.3s;
}

body.dark .game-container {
    background-color: #34495e;
    color: #ecf0f1;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

button {
    background-color: #4CAF50;
    color: white;
    border: none;
    padding: 12px 24px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 16px;
    margin: 4px 2px;
    cursor: pointer;
    border-radius: 25px;
    transition: all 0.3s;
}

button:hover {
    background-color: #45a049;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

#result {
    margin-top: 1em;
    font-weight: bold;
    font-size: 1.2em;
}

@media (max-width: 600px) {
    nav ul li {
        display: block;
        margin: 0.5em 0;
    }
    .game-container {
        margin: 1em;
        padding: 1em;
    }
}