/* Reset & Base */
* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #1e293b;
    --secondary-light: #334155;
    --success: #10b981;
    --success-light: #34d399;
    --warning: #f59e0b;
    --danger: #ef4444;
    --danger-light: #f87171;
    --light: #f8fafc;
    --dark: #0f172a;
    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;
    --sidebar-width: 270px;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --radius: 12px;
    --radius-sm: 8px;
    --radius-lg: 16px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--gray-100);
    color: var(--gray-800);
    line-height: 1.6;
    font-size: 14px;
    -webkit-font-smoothing: antialiased;
}

/* Login Page */
.login-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    background-size: 200% 200%;
    animation: gradientShift 15s ease infinite;
    position: relative;
    overflow: hidden;
}

.login-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.login-box {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    padding: 50px 40px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl), 0 0 40px rgba(102, 126, 234, 0.3);
    width: 100%;
    max-width: 420px;
    position: relative;
    z-index: 1;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.login-box h1 {
    text-align: center;
    color: var(--gray-900);
    margin-bottom: 8px;
    font-size: 1.75em;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.login-logo {
    display: block;
    width: 80px;
    height: 80px;
    margin: 0 auto 15px auto;
    border-radius: 16px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    object-fit: contain;
}

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

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: linear-gradient(180deg, var(--gray-900) 0%, var(--secondary) 100%);
    color: white;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    overflow-x: hidden;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 1000;
    box-shadow: 4px 0 20px rgba(0, 0, 0, 0.15);
}

.sidebar::-webkit-scrollbar {
    width: 6px;
}

.sidebar::-webkit-scrollbar-track {
    background: transparent;
}

.sidebar::-webkit-scrollbar-thumb {
    background: var(--gray-600);
    border-radius: 3px;
}

.sidebar-header {
    padding: 28px 24px;
    text-align: center;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    margin: 16px;
    border-radius: var(--radius);
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.sidebar-header h2 {
    font-size: 1.1em;
    margin-top: 12px;
    font-weight: 600;
    letter-spacing: -0.3px;
}

.sidebar-logo {
    width: 56px;
    height: 56px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
    object-fit: contain;
    background: white;
    padding: 4px;
}

.sidebar-nav {
    padding: 10px 0;
}

.nav-item {
    display: flex;
    align-items: center;
    padding: 14px 24px;
    color: var(--gray-400);
    text-decoration: none;
    transition: all 0.2s ease;
    border-left: 3px solid transparent;
    cursor: pointer;
    font-weight: 500;
    margin: 2px 8px;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.nav-item:hover {
    background: rgba(255, 255, 255, 0.08);
    color: white;
    transform: translateX(4px);
}

.nav-item.active {
    background: linear-gradient(90deg, rgba(99, 102, 241, 0.2) 0%, transparent 100%);
    color: white;
    border-left-color: var(--primary);
}

.nav-section {
    padding: 20px 24px 8px;
    font-size: 0.7em;
    text-transform: uppercase;
    color: var(--gray-500);
    letter-spacing: 1.5px;
    font-weight: 600;
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    min-height: 100vh;
    background: var(--gray-100);
}

/* Top Bar */
.top-bar {
    background: white;
    padding: 20px 32px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--gray-200);
}

.top-bar h1 {
    font-size: 1.5em;
    color: var(--gray-900);
    font-weight: 700;
    letter-spacing: -0.5px;
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 16px;
}

.user-info {
    text-align: right;
    padding: 8px 16px;
    background: var(--gray-50);
    border-radius: var(--radius-sm);
    border: 1px solid var(--gray-200);
}

.user-info .name {
    font-weight: 600;
    color: var(--gray-900);
    font-size: 0.95em;
}

.user-info .role {
    font-size: 0.8em;
    color: var(--primary);
    font-weight: 500;
    text-transform: capitalize;
}

/* Page Content */
.page-content {
    padding: 32px;
}

.page {
    display: none;
    animation: fadeIn 0.3s ease;
}

.page.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Cards */
.card {
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-bottom: 24px;
    border: 1px solid var(--gray-200);
    overflow: hidden;
    transition: box-shadow 0.2s ease;
}

.card:hover {
    box-shadow: var(--shadow-md);
}

.card-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--gray-100);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--gray-50);
}

.card-header h2 {
    font-size: 1.1em;
    color: var(--gray-900);
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 10px;
}

.card-body {
    padding: 24px;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
    margin-bottom: 32px;
}

.stat-card {
    background: white;
    border-radius: var(--radius);
    padding: 28px;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 20px;
    border: 1px solid var(--gray-200);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--primary-light));
    opacity: 0;
    transition: opacity 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-card:hover::before {
    opacity: 1;
}

.stat-icon {
    width: 64px;
    height: 64px;
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6em;
    color: white;
    flex-shrink: 0;
    box-shadow: var(--shadow-md);
}

.stat-icon.blue { background: linear-gradient(135deg, #6366f1, #4f46e5); }
.stat-icon.green { background: linear-gradient(135deg, #10b981, #059669); }
.stat-icon.orange { background: linear-gradient(135deg, #f59e0b, #d97706); }
.stat-icon.red { background: linear-gradient(135deg, #ef4444, #dc2626); }
.stat-icon.purple { background: linear-gradient(135deg, #8b5cf6, #7c3aed); }

.stat-info h3 {
    font-size: 1.9em;
    color: var(--gray-900);
    font-weight: 700;
    letter-spacing: -0.5px;
    line-height: 1.2;
}

.stat-info p {
    color: var(--gray-500);
    font-size: 0.9em;
    font-weight: 500;
    margin-top: 4px;
}

/* Tables */
.table-container {
    overflow-x: auto;
    border-radius: var(--radius-sm);
}

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

th, td {
    padding: 14px 16px;
    text-align: left;
    border-bottom: 1px solid var(--gray-100);
}

th {
    background: var(--gray-50);
    font-weight: 600;
    color: var(--gray-700);
    white-space: nowrap;
    font-size: 0.85em;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

tr {
    transition: background 0.15s ease;
}

tr:hover {
    background: var(--gray-50);
}

tr:last-child td {
    border-bottom: none;
}

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.75em;
    font-weight: 600;
    letter-spacing: 0.3px;
}

.badge-success { background: #dcfce7; color: #166534; }
.badge-warning { background: #fef3c7; color: #92400e; }
.badge-danger { background: #fee2e2; color: #991b1b; }
.badge-info { background: #dbeafe; color: #1e40af; }
.badge-secondary { background: var(--gray-100); color: var(--gray-600); }

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 11px 20px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    text-decoration: none;
    font-family: inherit;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    box-shadow: 0 2px 8px rgba(99, 102, 241, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.45);
}

.btn-success {
    background: linear-gradient(135deg, var(--success), #059669);
    color: white;
    box-shadow: 0 2px 8px rgba(16, 185, 129, 0.35);
}

.btn-success:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.45);
}

.btn-danger {
    background: linear-gradient(135deg, var(--danger), #dc2626);
    color: white;
}

.btn-secondary {
    background: var(--gray-100);
    color: var(--gray-700);
    border: 1px solid var(--gray-300);
}

.btn-secondary:hover {
    background: var(--gray-200);
}

.btn-sm {
    padding: 7px 14px;
    font-size: 12px;
}

.btn-icon {
    padding: 8px 12px;
    background: var(--gray-50);
    border: 1px solid var(--gray-200);
    color: var(--gray-600);
    border-radius: var(--radius-sm);
}

.btn-icon:hover {
    background: var(--gray-100);
    color: var(--primary);
    border-color: var(--primary-light);
}

/* Forms */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--gray-700);
    font-size: 0.9em;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-family: inherit;
    transition: all 0.2s ease;
    background: white;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.form-control::placeholder {
    color: var(--gray-400);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

select.form-control {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%2364748b' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10l-5 5z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 36px;
}

textarea.form-control {
    min-height: 100px;
    resize: vertical;
}

/* Checkbox styling */
input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--primary);
    cursor: pointer;
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    padding: 20px;
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: white;
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    transform: scale(0.95) translateY(20px);
    transition: transform 0.3s ease;
    box-shadow: var(--shadow-xl);
}

.modal-overlay.active .modal {
    transform: scale(1) translateY(0);
}

.modal-header {
    padding: 24px;
    border-bottom: 1px solid var(--gray-100);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--gray-50);
}

.modal-header h2 {
    color: var(--gray-900);
    font-weight: 700;
    font-size: 1.25em;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.75em;
    cursor: pointer;
    color: var(--gray-400);
    line-height: 1;
    transition: color 0.2s;
    padding: 4px;
}

.modal-close:hover {
    color: var(--gray-600);
}

.modal-body {
    padding: 24px;
}

.modal-footer {
    padding: 20px 24px;
    border-top: 1px solid var(--gray-100);
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    background: var(--gray-50);
}

/* Alerts */
.alert {
    padding: 16px 20px;
    border-radius: var(--radius-sm);
    margin-bottom: 20px;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 12px;
}

.alert-success { background: #dcfce7; color: #166534; border: 1px solid #bbf7d0; }
.alert-danger { background: #fee2e2; color: #991b1b; border: 1px solid #fecaca; }
.alert-warning { background: #fef3c7; color: #92400e; border: 1px solid #fde68a; }
.alert-info { background: #dbeafe; color: #1e40af; border: 1px solid #bfdbfe; }

/* Toast Notifications */
.toast-container {
    position: fixed;
    top: 24px;
    right: 24px;
    z-index: 3000;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.toast {
    background: white;
    padding: 16px 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: 12px;
    animation: toastSlide 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    font-weight: 500;
    min-width: 300px;
}

.toast.success { border-left: 4px solid var(--success); }
.toast.error { border-left: 4px solid var(--danger); }
.toast.warning { border-left: 4px solid var(--warning); }

@keyframes toastSlide {
    from { transform: translateX(120%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

/* Loading Spinner */
.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--gray-200);
    border-top: 4px solid var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 4000;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--gray-400);
}

.empty-state i {
    font-size: 4em;
    margin-bottom: 20px;
    opacity: 0.3;
}

/* Action Buttons */
.action-buttons {
    display: flex;
    gap: 8px;
}

/* Search & Filter Bar */
.filter-bar {
    display: flex;
    gap: 16px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.search-box {
    flex: 1;
    min-width: 200px;
    position: relative;
}

.search-box input {
    width: 100%;
    padding: 12px 16px 12px 44px;
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-sm);
    font-family: inherit;
}

.search-box i {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-400);
}

/* Invoice Items */
.invoice-item {
    background: var(--gray-50);
    padding: 16px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--gray-200);
}

/* Responsive */
@media (max-width: 1024px) {
    .sidebar {
        transform: translateX(-100%);
    }

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

    .main-content {
        margin-left: 0;
    }
}

@media (max-width: 768px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .page-content {
        padding: 20px;
    }

    .top-bar {
        padding: 16px 20px;
    }

    .top-bar h1 {
        font-size: 1.2em;
    }
}

/* Utility Classes */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-success { color: var(--success); }
.text-danger { color: var(--danger); }
.text-warning { color: var(--warning); }
.text-muted { color: var(--gray-500); }
.mb-0 { margin-bottom: 0; }
.mb-10 { margin-bottom: 10px; }
.mb-20 { margin-bottom: 20px; }
.mt-20 { margin-top: 20px; }
.hidden { display: none !important; }

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

::-webkit-scrollbar-track {
    background: var(--gray-100);
}

::-webkit-scrollbar-thumb {
    background: var(--gray-300);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--gray-400);
}

/* Print Styles */
@media print {
    .sidebar, .top-bar, .btn, .action-buttons { display: none !important; }
    .main-content { margin-left: 0; }
    .page-content { padding: 0; }
    .card { box-shadow: none; border: 1px solid #ddd; }
}

/* Selection */
::selection {
    background: var(--primary-light);
    color: white;
}