body {
    font-family: 'Poppins', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
    margin: 0;
}

.container {
    text-align: center;
    background: rgba(255, 255, 255, 0.95);
    padding: 3rem;
    border-radius: 20px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.3);
}

h1 {
    color: #0f2027;
}

button {
    padding: 15px 30px;
    font-size: 1.2rem;
    cursor: pointer;
    background: linear-gradient(to right, #2c5364, #0f2027);
    color: white;
    border: none;
    border-radius: 50px;
    margin-top: 1.5rem;
    transition: transform 0.2s, box-shadow 0.2s;
}

button:hover {
    transform: scale(1.05);
    box-shadow: 0 5px 15px rgba(0,0,0,0.4);
}

.result {
    margin-top: 2.5rem;
    text-align: left;
}

.set-container {
    margin-bottom: 1rem;
}

.number-circle {
    display: inline-block;
    width: 35px;
    height: 35px;
    line-height: 35px;
    border-radius: 50%;
    background: #2c5364;
    color: white;
    text-align: center;
    margin: 0 5px;
    font-weight: bold;
    font-size: 0.9rem;
}