:root {
    --primary-color: #4a4a4a;
    --secondary-color: #f5f5f5;
    --accent-color: #d63384;
    --text-color: #333;
    --background-color: #fff;
    --border-color: #ddd;
    --sidebar-bg: #2c3e50;
    --sidebar-text: #ecf0f1;
    --sidebar-active: #34495e;
    --danger-color: #dc3545;
    --success-color: #198754;
    --warning-color: #ffc107;
}
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; margin: 0; background-color: var(--secondary-color); color: var(--text-color); }
.container { display: flex; min-height: 100vh; }
.mobile-header { display: none; }
.sidebar-toggle { display: none; }
.sidebar { width: 250px; background-color: var(--sidebar-bg); color: var(--sidebar-text); display: flex; flex-direction: column; flex-shrink: 0; }
.sidebar-header { padding: 20px; text-align: center; }
.sidebar-header a, .mobile-title-link { text-decoration: none; color: inherit; }
.sidebar-header h2 { margin: 0; color: var(--accent-color); }
.sidebar-header-desktop { margin-top: 15px; padding-top: 15px; border-top: 1px solid var(--sidebar-active); }
.sidebar-header-desktop p a { color: var(--sidebar-text); text-decoration: none; }
.sidebar-header-desktop > a { color: var(--accent-color); text-decoration: none; }
.sidebar-footer { display: none; }
nav { flex-grow: 1; }
nav ul { list-style: none; padding: 0; margin: 20px 0; }
nav li a { display: block; padding: 12px 20px; text-decoration: none; color: var(--sidebar-text); transition: background-color 0.2s; }
nav li a:hover { background-color: var(--sidebar-active); }
hr { border: none; border-top: 1px solid var(--sidebar-active); margin: 10px 20px; }
.main-content { flex-grow: 1; padding: 30px; display: flex; flex-direction: column; position: relative;}
.main-header { margin-bottom: 20px; }
.main-header h1 { margin: 0; font-size: 2rem; }
.content { background-color: var(--background-color); padding: 20px; border-radius: 5px; box-shadow: 0 2px 4px rgba(0,0,0,0.1); }
.btn { display: inline-block; font-weight: 400; text-align: center; vertical-align: middle; cursor: pointer; border: 1px solid transparent; padding: 0.5rem 1rem; font-size: 1rem; line-height: 1.5; border-radius: 0.25rem; text-decoration: none; transition: all .15s ease-in-out; margin-bottom: 5px; }
.btn-primary { color: #fff; background-color: var(--accent-color); border-color: var(--accent-color); }
.btn-danger { color: #fff; background-color: var(--danger-color); border-color: var(--danger-color); }
.btn-secondary { color: var(--text-color); background-color: var(--secondary-color); border-color: var(--border-color); }
.btn-success { color: #fff; background-color: var(--success-color); border-color: var(--success-color); }
.btn-warning { color: #000; background-color: var(--warning-color); border-color: var(--warning-color); }
.form-group { margin-bottom: 1rem; }
.form-group label { display: block; margin-bottom: .5rem; font-weight: bold; }
.form-control { display: block; width: 100%; padding: 0.5rem 0.75rem; font-size: 1rem; line-height: 1.5; color: #495057; background-color: #fff; background-clip: padding-box; border: 1px solid #ced4da; border-radius: 0.25rem; box-sizing: border-box; }
span.error { color: var(--danger-color); font-size: 0.8em; display: block; margin-top: 4px; }
.data-table { width: 100%; border-collapse: collapse; margin-top: 20px; }
.data-table th, .data-table td { padding: 12px; text-align: left; border-bottom: 1px solid var(--border-color); vertical-align: middle; }
.data-table th { white-space: nowrap; }
.data-table thead th { background-color: var(--secondary-color); font-weight: bold; }
.data-table tbody tr:hover { background-color: #fafafa; }
.data-table a { color: var(--accent-color); text-decoration: none; }
.actions { margin-bottom: 20px; display: flex; gap: 10px; flex-wrap: wrap; }
.card { border: 1px solid var(--border-color); border-radius: 5px; }
.card-body { padding: 20px; }
.card-body p { margin: 0 0 10px; }
.card-footer { padding: 10px 20px; background-color: var(--secondary-color); border-top: 1px solid var(--border-color); }
.card-footer .btn, .card-footer form { margin-right: 10px; }
.flash { padding: 0.75rem 1.25rem; margin-bottom: 1rem; border: 1px solid transparent; border-radius: 0.25rem; }
.flash.success { color: #0f5132; background-color: #d1e7dd; border-color: #badbcc; }
.flash.danger { color: #842029; background-color: #f8d7da; border-color: #f5c2c7; }
.flash.info { color: #055160; background-color: #cff4fc; border-color: #b6effb; }
.modal { display: none; position: fixed; z-index: 1050; left: 0; top: 0; width: 100%; height: 100%; overflow: auto; background-color: rgba(0,0,0,0.8); }
.modal-content { background-color: #fff; margin: 10% auto; padding: 20px; border: 1px solid #888; width: 90%; max-width: 500px; text-align: center; border-radius: 5px; position: relative; }
.modal-content #qr-reader { border: 2px solid var(--accent-color); }
.modal-content img { max-width: 100%; height: auto; margin-top: 15px; margin-bottom: 15px; }
.close-button { color: #aaa; position: absolute; top: 10px; right: 20px; font-size: 28px; font-weight: bold; cursor: pointer; }
#back-to-top { display: none; position: fixed; bottom: 20px; right: 30px; z-index: 99; border-radius: 50%; width: 50px; height: 50px; font-size: 24px; padding: 0; }
@media (max-width: 768px) {
    .mobile-header { display: flex; align-items: center; justify-content: space-between; position: fixed; top: 0; left: 0; right: 0; height: 55px; background-color: var(--sidebar-bg); color: var(--sidebar-text); padding: 0 15px; z-index: 1001; box-shadow: 0 2px 5px rgba(0,0,0,0.2); }
    .mobile-header .mobile-title { margin: 0; font-size: 1.2rem; color: var(--accent-color); }
    .sidebar-header-desktop { display: none; }
    .sidebar-footer { display: block; padding: 20px; border-top: 1px solid var(--sidebar-active); text-align: center; }
    .sidebar-footer p a { color: var(--sidebar-text); text-decoration: none; }
    .sidebar-footer > a { color: var(--accent-color); text-decoration: none; }
    .sidebar-toggle { display: block; background: none; border: none; color: var(--sidebar-text); font-size: 24px; cursor: pointer; padding: 0; flex-shrink: 0; }
    .mobile-title-link { flex-grow: 1; text-align: center; color: inherit; }
    .scan-qr-btn { display: block; background: none; border: none; color: var(--sidebar-text); cursor: pointer; padding: 0; flex-shrink: 0; }
    .sidebar { position: fixed; top: 0; left: 0; bottom: 0; height: 100%; transform: translateX(-100%); transition: transform 0.3s ease-in-out; z-index: 1000; }
    .sidebar.is-open { transform: translateX(0); }
    .main-content { padding: 15px; padding-top: 70px; }
    .data-table td:nth-child(2), .data-table th:nth-child(2) { text-align: right; }
}