body {
    background: linear-gradient(135deg, #1a1a1a, #3d3d3d);
    color: #fff;
    font-family: 'Segoe UI', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.container {
    background: rgba(0,0,0,0.75);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 0 20px #00ff00;
    text-align: center;
}

input {
    display: block;
    margin: 0.5rem auto 1rem auto;
    padding: 0.5rem;
    width: 80%;
    border-radius: 5px;
    border: none;
}

button {
    padding: 0.7rem 1.5rem;
    border: none;
    border-radius: 10px;
    background-color: #00ff00;
    color: #fff;
    font-size: 1rem;
    cursor: pointer;
    transition: 0.3s;
}

button:hover {
    background-color: #4dff4d;
}

#result {
    margin-top: 1.5rem;
    font-size: 1.5rem;
    font-weight: bold;
}

.math-explanation {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid #00ff00;
    padding: 1rem;
    margin-top: 1.5rem;
    border-radius: 10px;
    text-align: left;
    color: #fff;
}

.math-explanation h2 {
    color: #4dff4d;
}