:root {
    --primary: #0d6efd;
    --secondary: #6c757d;
    --success: #198754;
    --danger: #dc3545;
    --bg-light: #f8f9fa;
    --text-dark: #212529;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-light);
    color: var(--text-dark);
    margin: 0;
    padding: 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.card {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 20px;
    margin-bottom: 20px;
}

.btn {
    display: inline-block;
    padding: 8px 16px;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 500;
    cursor: pointer;
    border: none;
}

.btn-primary { background: var(--primary); color: white; }
.btn-danger { background: var(--danger); color: white; }
.btn-success { background: var(--success); color: white; }

.table {
    width: 100%;
    border-collapse: collapse;
}

.table th, .table td {
    padding: 12px;
    border-bottom: 1px solid #dee2e6;
    text-align: left;
}

.badge {
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.85em;
    font-weight: bold;
    color: white;
}

.badge-active { background: var(--success); }
.badge-inactive { background: var(--secondary); }
.badge-expired { background: #ffc107; color: black; }
.badge-revoked { background: var(--danger); }

.nav-header {
    background: white;
    padding: 15px 0;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    margin-bottom: 30px;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-links a {
    margin-left: 20px;
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
}

.form-group {
    margin-bottom: 15px;
}

.form-control {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid #ced4da;
    border-radius: 4px;
    box-sizing: border-box;
}

.alert {
    padding: 15px;
    margin-bottom: 20px;
    border-radius: 4px;
}
.alert-danger { background: #f8d7da; color: #721c24; }
.alert-success { background: #d4edda; color: #155724; }