* {
    box-sizing: border-box;
    font-family: 'Segoe UI', sans-serif;
}

body {
    margin: 0;
    height: 100vh;
    background: linear-gradient(135deg, #6c5ce7, #00cec9);
    display: flex;
    justify-content: center;
    align-items: center;
}

.card {
    background: white;
    padding: 35px;
    width: 360px;
    border-radius: 15px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.2);
    text-align: center;
    animation: fadeIn 0.6s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(15px); }
    to { opacity: 1; transform: translateY(0); }
}

h1 {
    margin-bottom: 25px;
    color: #2d3436;
}

label {
    display: block;
    margin-bottom: 6px;
    font-weight: 600;
    color: #636e72;
}

input[type="number"] {
    width: 100%;
    padding: 10px;
    border-radius: 8px;
    border: 1px solid #ccc;
    margin-bottom: 15px;
    font-size: 16px;
}

button {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    background: linear-gradient(135deg, #0984e3, #6c5ce7);
    color: white;
    transition: transform 0.2s, box-shadow 0.2s;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.2);
}

.result {
    margin-top: 20px;
}

.result input {
    width: 100%;
    padding: 12px;
    font-size: 16px;
    border-radius: 8px;
    border: 1px solid #ccc;
    text-align: center;
    margin-bottom: 10px;
}

.copy {
    background: linear-gradient(135deg, #00b894, #00cec9);
}

#copied {
    display: block;
    margin-top: 8px;
    color: #00b894;
    font-weight: 600;
    opacity: 0;
    transition: opacity 0.3s;
}