:root {
    --bg-body: #f3f4f6;
    --bg-surface: #ffffff;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --success: #10b981;
    --warning: #f59e0b;
    --border: #e5e7eb;
    --sidebar-width: 250px;
    --radius: 8px;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: var(--bg-body);
    color: var(--text-main);
}

/* Layout */
.app-container {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: var(--sidebar-width);
    background-color: var(--bg-surface);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    transition: transform 0.3s ease;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.sidebar-header h2 {
    color: var(--primary);
    font-size: 1.5rem;
}

.close-sidebar {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
}

.sidebar-nav {
    padding: 20px 0;
    display: flex;
    flex-direction: column;
    gap: 5px;
}

.nav-link {
    padding: 12px 20px;
    text-decoration: none;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 10px;
    transition: background-color 0.2s;
}

.nav-link:hover {
    background-color: var(--bg-body);
    color: var(--primary);
}

.text-danger {
    color: var(--danger);
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    width: calc(100% - var(--sidebar-width));
}

.top-header {
    background-color: var(--bg-surface);
    height: 60px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-main);
}

.content-wrapper {
    padding: 20px;
    overflow-y: auto;
}

/* Cards & UI Elements */
.card {
    background-color: var(--bg-surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
    margin-bottom: 20px;
}

.flex-between {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

/* Buttons */
.btn {
    padding: 10px 16px;
    border-radius: var(--radius);
    border: none;
    cursor: pointer;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: background-color 0.2s;
    text-decoration: none;
    font-size: 0.9rem;
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
}

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

.btn-danger:hover {
    background-color: var(--danger-hover);
}

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

.btn-warning {
    background-color: var(--warning);
    color: white;
}

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

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
    color: var(--text-main);
}

.modern-input {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s;
}

.modern-input:focus {
    border-color: var(--primary);
}

/* Tables */
.table-responsive {
    overflow-x: auto;
}

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

.table th, .table td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.table th {
    background-color: var(--bg-body);
    font-weight: 600;
    color: var(--text-muted);
}

.badge {
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 600;
}

.badge-active { background-color: #d1fae5; color: #065f46; }
.badge-frozen { background-color: #dbeafe; color: #1e40af; }
.badge-expired { background-color: #fee2e2; color: #991b1b; }

/* Modals */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal {
    background-color: var(--bg-surface);
    border-radius: var(--radius);
    width: 100%;
    max-width: 500px;
    box-shadow: var(--shadow);
    animation: modalFadeIn 0.3s ease;
}

.modal-header {
    padding: 15px 20px;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    color: var(--text-muted);
}

.modal-body {
    padding: 20px;
}

.modal-footer {
    padding: 15px 20px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: flex-end;
    gap: 10px;
}

@keyframes modalFadeIn {
    from { opacity: 0; transform: translateY(-20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: 0;
        top: 0;
        height: 100%;
        z-index: 999;
        transform: translateX(-100%);
    }

    .sidebar.active {
        transform: translateX(0);
    }

    .main-content {
        width: 100%;
    }

    .menu-toggle, .close-sidebar {
        display: block;
    }
}

/* Login Page */
.login-page {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: var(--bg-body);
}

.login-card {
    width: 100%;
    max-width: 400px;
    padding: 30px;
    text-align: center;
}

.login-card h1 {
    margin-bottom: 20px;
    color: var(--primary);
}

.error-msg {
    color: var(--danger);
    margin-bottom: 15px;
    font-size: 0.9rem;
    display: none;
}