.lec-wrapper {
    max-width: 500px;
    margin: 30px auto;
    background: #fefefe;
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.1);
    font-family: 'Segoe UI', sans-serif;
}
.lec-wrapper h2 {
    color: #005a9e;
    text-align: center;
    margin-bottom: 20px;
}
.lec-field {
    margin-bottom: 15px;
}
.lec-field label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
}
.lec-field input[type=number] {
    width: 100%;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 6px;
}
.lec-result {
    margin-top: 20px;
    font-size: 20px;
    font-weight: bold;
    text-align: center;
    color: #007acc;
}