:root { --primary: #3498db; --dark: #2c3e50; --light: #f4f6f9; }
body { font-family: sans-serif; background-color: var(--light); margin: 0; padding: 0; }
nav { background-color: var(--dark); padding: 15px; display: flex; justify-content: space-between; align-items: center; }
nav h1, nav a { color: white; text-decoration: none; font-weight: bold; }
.container { max-width: 900px; margin: 40px auto; padding: 0 20px; }
.card { background: white; padding: 30px; border-radius: 8px; box-shadow: 0 4px 10px rgba(0,0,0,0.05); text-align: center; }
input[type="text"], input[type="password"] { width: 100%; padding: 12px; margin: 10px 0; border: 2px solid #bdc3c7; border-radius: 6px; box-sizing: border-box; }
.btn { background-color: var(--primary); color: white; border: none; padding: 12px; border-radius: 6px; cursor: pointer; width: 100%; font-weight: bold; }
table { width: 100%; border-collapse: collapse; margin-top: 20px; }
table, th, td { border: 1px solid #bdc3c7; padding: 10px; text-align: left; }
th { background-color: var(--dark); color: white; }
.alert { padding: 15px; margin-bottom: 20px; border-radius: 4px; text-align: left; }
.alert-success { background-color: #e8f8f5; border: 1px solid #2ecc71; }
.alert-danger { background-color: #fdebd0; border: 1px solid #e67e22; }