* {
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: #f5f5f5;
    color: #333;
}

header {
    background: #1e88e5;
    color: #fff;
    padding: 20px;
    text-align: center;
}

header h1 {
    margin: 0 0 8px 0;
}

.subtitle {
    margin: 0;
    font-size: 0.9rem;
    opacity: 0.9;
}

main {
    max-width: 700px;
    margin: 30px auto;
    padding: 0 16px 40px;
}

.card {
    background: #fff;
    border-radius: 10px;
    padding: 16px 20px;
    margin-bottom: 20px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.08);
}

.card h2 {
    margin-top: 0;
}

label {
    display: block;
    margin-top: 10px;
    font-weight: bold;
}

input {
    margin-top: 4px;
    padding: 8px;
    width: 100%;
    border-radius: 6px;
    border: 1px solid #ccc;
}

button {
    margin-top: 12px;
    padding: 8px 14px;
    border-radius: 6px;
    border: none;
    background: #1e88e5;
    color: #fff;
    cursor: pointer;
    font-weight: bold;
}

button:hover {
    background: #1565c0;
}

.resultado {
    margin-top: 12px;
    font-weight: bold;
    color: #2e7d32;
}

.erro {
    margin-top: 8px;
    color: #c62828;
    font-size: 0.9rem;
}

footer {
    text-align: center;
    font-size: 0.85rem;
    padding: 10px;
    color: #666;
}