* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}

body {
    background: linear-gradient(135deg, #667eea, #764ba2);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    width: 100%;
    max-width: 400px;
    padding: 20px;
}

.card {
    background: white;
    padding: 30px;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
    text-align: center;
}

h1 {
    margin-bottom: 20px;
}

input {
    width: 100%;
    padding: 12px;
    margin-bottom: 15px;
    border-radius: 8px;
    border: 1px solid #ccc;
    font-size: 16px;
}

input:focus {
    outline: none;
    border-color: #667eea;
}

#result {
    margin-top: 15px;
    font-size: 18px;
    font-weight: bold;
}