:root {
    --primary: #2c3e50;
    --secondary: #27ae60;
    --bg: #f4f6f8;
    --text: #333;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

/* Utilitários de Layout */
.container { width: 100%; max-width: 400px; padding: 20px; }
.card { background: white; padding: 2rem; border-radius: 8px; box-shadow: 0 4px 6px rgba(0,0,0,0.1); }
.btn { width: 100%; padding: 12px; background: var(--primary); color: white; border: none; border-radius: 4px; cursor: pointer; font-size: 1rem; }
.btn:hover { background: #34495e; }
input { width: 100%; padding: 10px; margin-bottom: 15px; border: 1px solid #ddd; border-radius: 4px; box-sizing: border-box; }
h2 { text-align: center; color: var(--primary); margin-top: 0; }
.error-msg { color: #e74c3c; text-align: center; margin-bottom: 10px; display: none; }