* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: linear-gradient(135deg, #1e3c72, #2a5298);
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.container {
    background: #ffffff;
    padding: 40px;
    border-radius: 12px;
    text-align: center;
    width: 320px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

h1 {
    margin-top: 0;
    color: #2a5298;
}

button {
    margin-top: 20px;
    padding: 10px 20px;
    border: none;
    border-radius: 6px;
    background: #2a5298;
    color: white;
    font-size: 16px;
    cursor: pointer;
}

button:hover {
    background: #1e3c72;
}

#result {
    margin-top: 15px;
    color: green;
    font-weight: bold;
}