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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f0f2f5;
    background-image: radial-gradient(#d7d7d7 1px, transparent 0);
    background-size: 40px 40px;
}

.container {
    text-align: center;
    background-color: #ffffff;
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    width: 90%;
    max-width: 500px;
}

h1 {
    margin-bottom: 30px;
    font-size: 2.5rem;
    color: #333;
    font-weight: 700;
}

.numbers-container {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 30px;
    min-height: 80px;
}

.number-circle {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.8rem;
    font-weight: 600;
    color: #fff;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease, background-color 0.3s ease;
}

#generate-btn {
    background-color: #4CAF50;
    color: white;
    padding: 15px 30px;
    border: none;
    border-radius: 8px;
    font-size: 1.2rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.3s, box-shadow 0.3s;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

#generate-btn:hover {
    background-color: #45a049;
    box-shadow: 0 0 20px rgba(76, 175, 80, 0.7);
}

@media (max-width: 600px) {
    h1 {
        font-size: 2rem;
    }

    .number-circle {
        width: 50px;
        height: 50px;
        font-size: 1.5rem;
    }

    #generate-btn {
        padding: 12px 25px;
        font-size: 1rem;
    }
}