body {
    font-family: 'Poppins', sans-serif;
    background-color: #1a1a1a;
    background-image: url("data:image/svg+xml,%3Csvg width='40' height='40' viewBox='0 0 40 40' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='%23333333' fill-opacity='0.1' fill-rule='evenodd'%3E%3Cpath d='M0 40L40 0H20L0 20M40 40V20L20 40'/%3E%3C/g%3E%3C/svg%3E");
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
}

.container {
    text-align: center;
    background: #2c2c2c;
    padding: 40px;
    border-radius: 20px;
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.5), 0 0 40px rgba(13, 110, 253, 0.3);
    width: 100%;
    max-width: 600px;
}

.header h1 {
    color: #fff;
    font-size: 2.5em;
    font-weight: 700;
    margin-bottom: 5px;
}

.header p {
    color: #ccc;
    margin-bottom: 30px;
}

.controls {
    margin-bottom: 30px;
    color: #fff;
}

.controls label {
    margin-right: 10px;
    font-weight: 600;
}

.controls select {
    padding: 8px 12px;
    border-radius: 8px;
    border: 1px solid #555;
    background: #333;
    color: #fff;
    font-family: 'Poppins', sans-serif;
}

.sets-container {
    display: grid;
    gap: 20px;
    margin-bottom: 40px;
}

.number-set {
    display: flex;
    justify-content: center;
    gap: 10px;
    background: rgba(0, 0, 0, 0.2);
    padding: 15px;
    border-radius: 12px;
}

.number {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    color: white;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 22px;
    font-weight: 600;
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
    animation: appear 0.5s ease-out forwards;
    transform: scale(0);
}

#generate-button {
    background-image: linear-gradient(45deg, #0d6efd, #0d6efd);
    color: white;
    border: none;
    padding: 15px 40px;
    font-size: 18px;
    font-weight: 600;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 0 20px rgba(13, 110, 253, 0.5);
}

#generate-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 25px rgba(13, 110, 253, 0.7);
}

@keyframes appear {
    to {
        transform: scale(1);
    }
}