* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Hiragino Kaku Gothic Pro', 'Meiryo', sans-serif;
    background-color: #f5f5f5;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    text-align: center;
}

.container {
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    padding: 2rem;
    width: 90%;
    max-width: 600px;
}

h1 {
    color: #e67e22;
    margin-bottom: 2rem;
    font-size: 2rem;
}

.world-display {
    background-color: #f9f9f9;
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 2rem;
    min-height: 150px;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s ease;
}

.world-display p {
    font-size: 1.5rem;
    font-weight: bold;
    color: #333;
}

button {
    background-color: #e67e22;
    color: white;
    border: none;
    border-radius: 5px;
    padding: 1rem 2rem;
    font-size: 1.2rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #d35400;
}

.world-text {
    font-size: 2rem;
    font-weight: bold;
    color: #333;
}

@media (max-width: 480px) {
    .container {
        padding: 1rem;
    }
    
    h1 {
        font-size: 1.5rem;
    }
    
    .world-display p, .world-text {
        font-size: 1.2rem;
    }
    
    button {
        padding: 0.8rem 1.5rem;
        font-size: 1rem;
    }
}