:root {
    --sidebar-bg: #e6f1ed;
    --sidebar-active: #d0e7df;
    --sidebar-icon: #6ba292;
    --primary-color: #3ca97b;
    --primary-dark: #2e7d32;
    --primary-light: #e6f1ed;
    --card-bg: #f8fbfa;
    --card-border: #e0e7e3;
    --text-dark: #1a2b2b;
    --text-light: #6ba292;
    --accent: #4bbf73;
    --danger: #e57373;
    --warning: #ffb300;
    --success: #4bbf73;
    --muted: #b0bfc6;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--primary-light);
    color: var(--text-dark);
    line-height: 1.6;
}

/* Navigation */
.navbar {
    background-color: var(--primary-color) !important;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.navbar-brand {
    font-weight: bold;
    color: white !important;
}

.navbar-nav .nav-link {
    color: rgba(255,255,255,0.9) !important;
    font-weight: 500;
    transition: color 0.3s ease;
}

.navbar-nav .nav-link:hover {
    color: white !important;
}

/* Sidebar */
.sidebar {
    background: var(--sidebar-bg);
    min-height: 100vh;
    width: 260px;
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    z-index: 100;
    display: flex;
    flex-direction: column;
    padding: 32px 0 0 0;
    border-right: 1px solid var(--card-border);
}
.sidebar .profile {
    text-align: center;
    margin-bottom: 32px;
}
.sidebar .profile-icon {
    width: 72px;
    height: 72px;
    border-radius: 50%;
    background: var(--primary-light);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 12px auto;
    border: 2px solid var(--primary-color);
}
.sidebar .profile img {
    width: 72px;
    height: 72px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 12px;
}
.sidebar .profile h5 {
    margin-bottom: 2px;
    font-size: 1.2rem;
    font-weight: 600;
}
.sidebar .profile p {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 0;
}
.sidebar .nav {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.sidebar .nav-link {
    color: var(--text-dark);
    font-weight: 500;
    border-radius: 8px 0 0 8px;
    padding: 12px 24px;
    display: flex;
    align-items: center;
    gap: 14px;
    transition: background 0.2s, color 0.2s;
}
.sidebar .nav-link.active, .sidebar .nav-link:hover {
    background: var(--sidebar-active);
    color: var(--primary-color);
}
.sidebar .nav-link i {
    color: var(--sidebar-icon);
    font-size: 1.2rem;
}
.sidebar .logout {
    margin-top: auto;
    padding: 24px 0 0 0;
}

/* Main content area */
.main-content {
    margin-left: 260px;
    padding: 40px 32px 32px 32px;
    min-height: 100vh;
    background: var(--primary-light);
}

/* Cards */
.card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 18px;
    box-shadow: none;
    margin-bottom: 24px;
    padding: 18px 12px;
}
.card-header {
    background: transparent;
    border-bottom: none;
    font-weight: 600;
    color: var(--primary-color);
    padding: 18px 12px;
}
.card-body {
    padding: 18px 12px;
}

/* Dashboard summary cards */
.summary-cards {
    display: flex;
    gap: 20px;
    margin-bottom: 32px;
}
.summary-card {
    flex: 1;
    background: #fff;
    border-radius: 16px;
    padding: 20px 18px;
    box-shadow: 0 2px 8px rgba(60, 169, 123, 0.04);
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    border: 1px solid var(--card-border);
}
.summary-card h2 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 6px;
    color: var(--primary-color);
}
.summary-card p {
    color: var(--muted);
    font-size: 0.95rem;
    margin-bottom: 0;
}

/* Buttons */
.btn, .btn-primary {
    border-radius: 10px;
    font-weight: 600;
    font-size: 1rem;
    padding: 12px 28px;
    background: var(--primary-color);
    border: none;
    color: #fff;
    transition: background 0.2s;
    margin-bottom: 8px;
}
.btn-primary:hover, .btn:hover {
    background: var(--primary-dark);
    color: #fff;
}
.btn-outline-secondary {
    border: 1.5px solid var(--primary-color);
    color: var(--primary-color);
    background: #fff;
}
.btn-outline-secondary:hover {
    background: var(--primary-color);
    color: #fff;
}

/* Table */
.table {
    background: #fff;
    border-radius: 12px;
    overflow: hidden;
    font-size: 1rem;
    margin-bottom: 1.5rem;
}
.table th {
    background: var(--primary-light);
    color: var(--primary-color);
    font-weight: 600;
    border: none;
}
.table td {
    border: none;
}

/* Chart area */
.chart-container {
    background: #fff;
    border-radius: 16px;
    padding: 24px 18px 12px 18px;
    margin-bottom: 24px;
    border: 1px solid var(--card-border);
}

/* Recent activity */
.recent-activity {
    background: #fff;
    border-radius: 16px;
    padding: 18px 18px 8px 18px;
    border: 1px solid var(--card-border);
}
.recent-activity .activity-row {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 10px 0;
    border-bottom: 1px solid var(--card-border);
}
.recent-activity .activity-row:last-child {
    border-bottom: none;
}
.recent-activity .activity-icon {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--primary-light);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    font-size: 1.3rem;
}

/* Responsive Design - Mobile First Approach */

/* Hamburger menu for mobile */
.hamburger {
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    position: fixed !important;
}

.hamburger span,
.hamburger span:before,
.hamburger span:after {
    display: block;
    background: var(--primary-color);
    height: 4px;
    width: 24px;
    border-radius: 2px;
    position: absolute;
    left: 10px;
    right: 10px;
    margin: 0 auto;
    transition: 0.3s;
}

.hamburger span {
    position: absolute;
    top: 20px;
    left: 10px;
    right: 10px;
    margin: 0 auto;
}

.hamburger span:before,
.hamburger span:after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
}

.hamburger span:before {
    top: -8px;
}

.hamburger span:after {
    top: 8px;
}

/* Sidebar overlay for mobile */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.25);
    z-index: 99;
}

/* Loading spinner */
.spinner-border {
    color: var(--primary-color);
}

/* Custom scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-dark);
}

/* Tablet and Mobile Responsive Design */
@media (max-width: 1024px) {
    .sidebar {
        left: -260px !important;
        position: fixed !important;
        width: 240px !important;
        z-index: 2000 !important;
        transition: left 0.3s cubic-bezier(0.4,0,0.2,1);
    }
    .sidebar.open {
        left: 0 !important;
    }
    .sidebar-overlay {
        z-index: 1999 !important;
    }
    .sidebar-overlay.open {
        display: block !important;
    }
    .main-content {
        margin-left: 0 !important;
        width: 100% !important;
        box-sizing: border-box !important;
        padding-left: 0 !important;
        padding-right: 0 !important;
    }
    
    .summary-cards {
        flex-direction: column;
        gap: 16px;
    }
    
    .summary-card {
        padding: 20px 16px;
    }
    
    .summary-card h2 {
        font-size: 1.8rem;
    }
    
    .card, .card-header, .card-body {
        border-radius: 12px !important;
    }
    
    .table-responsive {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }
    
    /* Improve table readability on mobile */
    .table {
        font-size: 0.9rem;
    }
    
    .table th, .table td {
        padding: 8px 6px;
        white-space: nowrap;
    }
    
    /* Stack buttons on mobile */
    .btn + .btn {
        margin-left: 0;
        margin-top: 8px;
    }
    
    /* Improve form layout */
    .form-control, .form-select {
        font-size: 1rem;
        padding: 10px 12px;
    }
    
    /* Chart responsiveness */
    .chart-container {
        height: 300px;
        overflow: hidden;
    }
    
    /* Recent activity improvements */
    .recent-activity .activity-row {
        padding: 12px 8px;
    }
    
    .recent-activity .activity-icon {
        width: 32px;
        height: 32px;
        font-size: 0.8rem;
    }
    
    /* --- CRITICAL: Hamburger menu always visible on mobile --- */
    .hamburger {
        width: 44px !important;
        height: 44px !important;
        padding: 0 !important;
    }
    .hamburger span,
    .hamburger span:before,
    .hamburger span:after {
        width: 24px !important;
        left: 10px !important;
        right: 10px !important;
        margin: 0 auto !important;
    }
    .hamburger span {
        top: 20px !important;
        left: 10px !important;
        right: 10px !important;
    }
    .hamburger span:before {
        top: -8px !important;
    }
    .hamburger span:after {
        top: 8px !important;
    }
}

@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.3s ease;
        width: 280px;
    }
    .sidebar.open {
        transform: translateX(0);
    }
    .sidebar-overlay {
        display: none;
    }
    .sidebar-overlay.open {
        display: block;
    }
    .main-content {
        margin-left: 0;
        padding: 20px 16px;
        width: 100%;
    }
    .summary-cards {
        flex-direction: column;
        gap: 16px;
    }
    .summary-card {
        padding: 16px;
    }
    .summary-card h2 {
        font-size: 1.6rem;
    }
    .card, .card-header, .card-body {
        padding: 12px;
    }
    .table-responsive {
        font-size: 0.9rem;
    }
    .table {
        font-size: 0.85rem;
    }
    .table th, .table td {
        padding: 8px 6px;
        vertical-align: middle;
    }
    .btn + .btn {
        margin-left: 4px;
    }
    .form-control, .form-select {
        font-size: 16px;
        padding: 10px 12px;
    }
    .chart-container {
        height: 250px;
    }
    .recent-activity .activity-row {
        padding: 12px 0;
    }
    .recent-activity .activity-icon {
        width: 36px;
        height: 36px;
        font-size: 0.9rem;
    }
    .hamburger {
        display: block;
        position: fixed;
        top: 20px;
        left: 20px;
        z-index: 1000;
        background: var(--primary-color);
        border: none;
        border-radius: 8px;
        width: 44px;
        height: 44px;
        cursor: pointer;
        box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    }
    .hamburger span,
    .hamburger span:before,
    .hamburger span:after {
        display: block;
        background: white;
        height: 3px;
        width: 24px;
        position: absolute;
        left: 10px;
        transition: all 0.3s ease;
    }
    .hamburger span {
        top: 20px;
    }
    .hamburger span:before {
        content: '';
        top: -8px;
    }
    .hamburger span:after {
        content: '';
        top: 8px;
    }
    .sidebar .profile-icon {
        width: 60px;
        height: 60px;
    }
    .sidebar .profile-icon i {
        font-size: 1.5rem !important;
    }
    .sidebar .profile h5 {
        font-size: 1.1rem;
    }
    .sidebar .profile p {
        font-size: 0.9rem;
    }
    .sidebar .nav-link {
        padding: 10px 20px;
        font-size: 0.95rem;
    }
    .sidebar .nav-link i {
        font-size: 1.1rem;
    }
}

@media (max-width: 480px) {
    .main-content {
        padding: 60px 8px 8px 8px;
    }
    
    .summary-card {
        padding: 12px 8px;
    }
    
    .summary-card h2 {
        font-size: 1.4rem;
    }
    
    .card {
        padding: 8px 6px;
        margin-bottom: 12px;
    }
    
    .card-header {
        padding: 8px 6px;
        font-size: 0.95rem;
    }
    
    .card-body {
        padding: 8px 6px;
    }
    
    /* Improve table for very small screens */
    .table {
        font-size: 0.8rem;
    }
    
    .table th, .table td {
        padding: 6px 4px;
    }
    
    /* Better form controls */
    .form-control, .form-select {
        font-size: 0.95rem;
        padding: 8px 10px;
    }
    
    /* Improve chart container */
    .chart-container {
        height: 250px;
    }
    
    /* Sidebar for very small screens */
    .sidebar {
        width: 90vw;
    }
    
    .sidebar .nav-link {
        padding: 8px 12px;
        font-size: 0.9rem;
    }
    
    .sidebar .nav-link i {
        font-size: 1rem;
    }
    
    /* Improve hamburger positioning */
    .hamburger {
        top: 12px;
        left: 12px;
        width: 36px;
        height: 36px;
    }
    
    .hamburger span, .hamburger span:before, .hamburger span:after {
        width: 20px;
        left: 8px;
    }
    
    .hamburger span {
        top: 16px;
    }
    
    .hamburger span:before {
        top: -6px;
    }
    
    .hamburger span:after {
        top: 6px;
    }
}

/* Authentication pages responsive */
@media (max-width: 600px) {
    .auth-container {
        padding: 16px;
    }
    
    .auth-card {
        padding: 32px 24px;
        margin: 0 8px;
    }
    
    .auth-logo h1 {
        font-size: 1.8rem;
    }
    
    .auth-card .form-control {
        font-size: 0.95rem;
        padding: 10px 12px;
    }
    
    .auth-card .btn-primary {
        padding: 12px 24px;
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .auth-container {
        padding: 12px;
    }
    
    .auth-card {
        padding: 24px 16px;
    }
    
    .auth-logo h1 {
        font-size: 1.6rem;
    }
    
    .auth-logo p {
        font-size: 1rem;
    }
}

/* Landscape orientation fixes */
@media (max-width: 768px) and (orientation: landscape) {
    .main-content {
        padding: 50px 12px 12px 12px;
    }
    
    .summary-cards {
        flex-direction: row;
        flex-wrap: wrap;
        gap: 12px;
    }
    
    .summary-card {
        flex: 1;
        min-width: 200px;
    }
    
    .chart-container {
        height: 200px;
    }
}

/* High DPI displays */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    .hamburger {
        box-shadow: 0 1px 4px rgba(60, 169, 123, 0.12);
    }
    
    .sidebar {
        box-shadow: 1px 0 4px rgba(60, 169, 123, 0.12);
    }
}

/* Touch device improvements */
@media (hover: none) and (pointer: coarse) {
    .btn, .nav-link, .form-control, .form-select {
        min-height: 44px;
    }
    
    .sidebar .nav-link {
        min-height: 48px;
    }
    
    .hamburger {
        min-width: 44px;
        min-height: 44px;
    }
}

/* Enhanced table responsiveness */
@media (max-width: 768px) {
    /* Tab navigation improvements */
    .nav-tabs {
        flex-wrap: wrap;
        border-bottom: 1px solid var(--card-border);
    }
    
    .nav-tabs .nav-link {
        font-size: 0.85rem;
        padding: 8px 12px;
        white-space: nowrap;
    }
    
    /* Table improvements for mobile */
    .table-responsive {
        border: 1px solid var(--card-border);
        border-radius: 8px;
        margin-bottom: 16px;
    }
    
    .table {
        margin-bottom: 0;
    }
    
    .table th {
        font-size: 0.8rem;
        padding: 8px 4px;
        white-space: nowrap;
    }
    
    .table td {
        font-size: 0.8rem;
        padding: 6px 4px;
        vertical-align: middle;
    }
    
    /* Compact badges */
    .badge {
        font-size: 0.7rem;
        padding: 4px 6px;
    }
    
    /* Compact buttons in tables */
    .table .btn-sm {
        padding: 4px 6px;
        font-size: 0.75rem;
    }
    
    .table .btn-sm i {
        font-size: 0.7rem;
    }
    
    /* Improve action buttons spacing */
    .table td:last-child {
        white-space: nowrap;
    }
    
    .table td:last-child .btn {
        margin: 0 2px;
    }
    
    /* Stack header elements on mobile */
    .d-flex.justify-content-between {
        flex-direction: column;
        gap: 12px;
        align-items: flex-start !important;
    }
    
    .d-flex.justify-content-between h1 {
        font-size: 1.5rem;
        margin-bottom: 0;
    }
    
    .d-flex.justify-content-between .btn {
        width: 100%;
        margin-bottom: 8px;
    }
    
    .d-flex.justify-content-between .btn:last-child {
        margin-bottom: 0;
    }
}

@media (max-width: 480px) {
    /* Even more compact tables */
    .table th {
        font-size: 0.75rem;
        padding: 6px 2px;
    }
    
    .table td {
        font-size: 0.75rem;
        padding: 4px 2px;
    }
    
    /* Hide less important columns on very small screens */
    .table th:nth-child(4),
    .table td:nth-child(4),
    .table th:nth-child(5),
    .table td:nth-child(5) {
        display: none;
    }
    
    /* Compact tab navigation */
    .nav-tabs .nav-link {
        font-size: 0.8rem;
        padding: 6px 8px;
    }
    
    .nav-tabs .nav-link i {
        display: none;
    }
    
    /* Improve modal responsiveness */
    .modal-dialog {
        margin: 10px;
        max-width: calc(100% - 20px);
    }
    
    .modal-body {
        padding: 16px 12px;
    }
    
    .modal-header {
        padding: 12px 16px;
    }
    
    .modal-footer {
        padding: 12px 16px;
    }
}

/* Print styles for better table printing */
@media print {
    .sidebar,
    .hamburger,
    .sidebar-overlay,
    .btn,
    .nav-tabs {
        display: none !important;
    }
    
    .main-content {
        margin-left: 0 !important;
        padding: 0 !important;
    }
    
    .table-responsive {
        overflow: visible !important;
        border: none !important;
    }
    
    .table {
        font-size: 12px !important;
    }
    
    .card {
        border: none !important;
        box-shadow: none !important;
    }
}

/* Form responsiveness improvements */
@media (max-width: 768px) {
    /* Stack form columns on mobile */
    .row .col-md-4,
    .row .col-md-6,
    .row .col-lg-4,
    .row .col-lg-6 {
        margin-bottom: 16px;
    }
    
    /* Improve form spacing */
    .form-label {
        font-size: 0.95rem;
        margin-bottom: 6px;
    }
    
    .form-control,
    .form-select {
        font-size: 1rem;
        padding: 12px 14px;
        border-radius: 8px;
    }
    
    /* Better button layout on mobile */
    .d-flex.justify-content-end {
        flex-direction: column;
        gap: 8px;
    }
    
    .d-flex.justify-content-end .btn {
        width: 100%;
        margin: 0;
    }
    
    /* Improve card layout */
    .card-body {
        padding: 16px 12px;
    }
    
    /* Better IMEI input layout */
    .d-flex .form-control {
        flex: 1;
    }
    
    .d-flex .btn {
        flex-shrink: 0;
        margin-left: 8px;
    }
    
    /* Improve bulk IMEI list */
    #bulkImeiList {
        min-height: 80px;
        max-height: 200px;
        overflow-y: auto;
    }
    
    /* Better modal form layout */
    .modal-body .row {
        margin: 0;
    }
    
    .modal-body .col-md-4,
    .modal-body .col-md-6 {
        padding: 0 0 16px 0;
    }
}

@media (max-width: 480px) {
    /* Even more compact forms */
    .form-control,
    .form-select {
        font-size: 0.95rem;
        padding: 10px 12px;
    }
    
    .form-label {
        font-size: 0.9rem;
    }
    
    /* Stack all form elements */
    .row .col-md-4,
    .row .col-md-6,
    .row .col-lg-4,
    .row .col-lg-6 {
        width: 100%;
        margin-bottom: 12px;
    }
    
    /* Compact card spacing */
    .card-body {
        padding: 12px 8px;
    }
    
    .card-header {
        padding: 12px 8px;
    }
    
    /* Better button sizing */
    .btn {
        padding: 10px 16px;
        font-size: 0.9rem;
    }
    
    /* Improve IMEI scanner button */
    .d-flex .btn {
        padding: 10px 12px;
        font-size: 0.85rem;
    }
    
    .d-flex .btn i {
        font-size: 0.8rem;
    }
}

/* Improved form and button spacing */
.form-label, label {
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-control, .form-select {
    padding: 12px 16px;
    border-radius: 8px;
    font-size: 1.05rem;
    margin-bottom: 18px;
}

.form-control:focus, .form-select:focus {
    box-shadow: 0 0 0 2px var(--primary-color, #3ca97b33);
    border-color: var(--primary-color);
}

.form-group, .mb-3, .mb-4 {
    margin-bottom: 1.25rem !important;
}

.btn + .btn {
    margin-left: 10px;
}

/* Authentication pages */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-light);
    padding: 20px;
}

.auth-card {
    background: #fff;
    border-radius: 18px;
    padding: 40px;
    box-shadow: 0 4px 20px rgba(60, 169, 123, 0.1);
    border: 1px solid var(--card-border);
    width: 100%;
    max-width: 450px;
}

.auth-logo {
    text-align: center;
    margin-bottom: 32px;
}

.auth-logo h1 {
    color: var(--primary-color);
    font-weight: 700;
    margin-bottom: 8px;
}

.auth-logo p {
    color: var(--text-light);
    font-size: 1.1rem;
    margin-bottom: 0;
}

.auth-card .form-label {
    color: var(--text-dark);
    font-weight: 600;
    margin-bottom: 8px;
}

.auth-card .form-control {
    border: 2px solid var(--card-border);
    border-radius: 10px;
    padding: 12px 16px;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.auth-card .form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(60, 169, 123, 0.25);
}

.auth-card .btn-primary {
    padding: 14px 28px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 10px;
    background: var(--primary-color);
    border: none;
    transition: background 0.2s;
}

.auth-card .btn-primary:hover {
    background: var(--primary-dark);
}

.auth-card .alert {
    border-radius: 10px;
    border: none;
    margin-bottom: 24px;
}

.auth-card .alert-error {
    background: rgba(229, 115, 115, 0.1);
    color: var(--danger);
}

.auth-card .alert-success {
    background: rgba(75, 191, 115, 0.1);
    color: var(--success);
}

.auth-card a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

.auth-card a:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}