* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Roboto', sans-serif;
    background: linear-gradient(135deg, #00a651, #007a3d);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    color: #fff;
}

.container {
    background: white;
    color: #333;
    border-radius: 20px;
    box-shadow: 0 15px 35px rgba(0,0,0,0.3);
    padding: 40px;
    max-width: 480px;
    width: 100%;
    text-align: center;
}

h1 {
    color: #00a651;
    margin-bottom: 10px;
    font-size: 2.2rem;
}

p {
    margin-bottom: 25px;
    color: #555;
}

.cpf-display {
    font-size: 2.8rem;
    font-weight: bold;
    letter-spacing: 4px;
    background: #f8f9fa;
    padding: 20px;
    border-radius: 12px;
    margin: 25px 0;
    border: 3px solid #00a651;
    color: #00a651;
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
}

button {
    background: #00a651;
    color: white;
    border: none;
    padding: 14px 28px;
    font-size: 1.1rem;
    border-radius: 50px;
    cursor: pointer;
    margin: 10px 5px;
    transition: all 0.3s;
}

button:hover {
    background: #007a3d;
    transform: scale(1.05);
}

hr {
    margin: 40px 0;
    border-color: #eee;
}

h2 {
    color: #333;
    margin-bottom: 15px;
}

.cpf-input {
    width: 100%;
    padding: 14px;
    font-size: 1.1rem;
    border: 2px solid #ddd;
    border-radius: 10px;
    text-align: center;
    margin-bottom: 15px;
}

.result {
    margin-top: 20px;
    font-weight: bold;
    padding: 15px;
    border-radius: 10px;
    min-height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.valid {
    background: #d4edda;
    color: #155724;
}

.invalid {
    background: #f8d7da;
    color: #721c24;
}

footer {
    margin-top: 40px;
    font-size: 0.9rem;
    color: #666;
}