body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #74ebe1 0%, #d4a5ec 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}
.calculator {
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
    text-align: center;
    width: 320px;
}
h2 {
    color: #333;
    margin-bottom: 20px;
    font-size: 1.5rem;
}
input {
    width: 100%;
    padding: 12px;
    margin: 10px 0;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    box-sizing: border-box;
    font-size: 1rem;
    transition: border-color 0.3s;
}
input:focus {
    border-color: #a55eea;
    outline: none;
}
button {
    width: 100%;
    padding: 12px;
    background: #a55eea;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    font-weight: bold;
    transition: background 0.3s;
    margin-top: 10px;
}
button:hover {
    background: #8843d1;
}
.result {
    margin-top: 20px;
    font-size: 1.2rem;
    font-weight: bold;
    color: #2d3436;
    padding: 10px;
    background: #f5f6fa;
    border-radius: 6px;
}