/* CSS Variables */
:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --background-color: #f1f5f9;
    --card-background: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --sidebar-width: 260px;
    --header-height: 70px;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
}

/* Page Management */
.page {
    display: none;
    min-height: 100vh;
}

.page.active {
    display: flex;
}

/* Login Page */
.login-container {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    width: 100%;
    background: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
    padding: 20px;
}

.login-card {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    padding: 40px;
    width: 100%;
    max-width: 420px;
    box-shadow: var(--shadow-lg);
}

.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.login-header h1 {
    font-size: 28px;
    color: var(--primary-color);
    margin-bottom: 8px;
}

.login-header p {
    color: var(--text-secondary);
}

.login-footer {
    text-align: center;
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
}

.login-footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.login-footer a:hover {
    text-decoration: underline;
}

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

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    font-size: 14px;
    color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 14px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 14px;
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group input:read-only {
    background-color: var(--background-color);
    cursor: default;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

@media (max-width: 600px) {
    .form-row {
        grid-template-columns: 1fr;
    }
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
}

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

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

.btn-secondary {
    background-color: var(--background-color);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

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

.btn-danger:hover {
    background-color: #dc2626;
}

.btn-small {
    padding: 6px 12px;
    font-size: 12px;
}

.btn-full {
    width: 100%;
}

.btn-icon {
    padding: 8px;
    min-width: 36px;
}

/* App Layout */
#app-page {
    display: none;
}

#app-page.active {
    display: flex;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--card-background);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: fixed;
    height: 100vh;
    left: 0;
    top: 0;
    z-index: 100;
    transition: transform 0.3s;
}

.sidebar-header {
    padding: 24px;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h2 {
    font-size: 20px;
    color: var(--primary-color);
}

.nav-menu {
    list-style: none;
    padding: 16px 12px;
    flex: 1;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    border-radius: var(--radius-md);
    cursor: pointer;
    color: var(--text-secondary);
    font-weight: 500;
    transition: all 0.2s;
    margin-bottom: 4px;
}

.nav-item:hover {
    background-color: var(--background-color);
    color: var(--text-primary);
}

.nav-item.active {
    background-color: var(--primary-color);
    color: white;
}

.nav-icon {
    font-size: 18px;
}

.sidebar-footer {
    padding: 16px;
    border-top: 1px solid var(--border-color);
}

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

.top-header {
    height: var(--header-height);
    background: var(--card-background);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 30px;
    position: sticky;
    top: 0;
    z-index: 50;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 16px;
}

.header-left h1 {
    font-size: 22px;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    padding: 8px;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 16px;
}

#user-name {
    font-weight: 500;
    color: var(--text-secondary);
}

.content-area {
    padding: 30px;
}

/* Content Sections */
.content-section {
    display: none;
}

.content-section.active {
    display: block;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
}

.section-header h2 {
    font-size: 20px;
}

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

.search-filter input,
.search-filter select {
    padding: 10px 14px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 14px;
    min-width: 200px;
}

.search-filter input {
    flex: 1;
    max-width: 400px;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    padding: 24px;
    display: flex;
    align-items: center;
    gap: 20px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.stat-card.warning {
    border-left: 4px solid var(--warning-color);
}

.stat-card.danger {
    border-left: 4px solid var(--danger-color);
}

.stat-icon {
    font-size: 32px;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--background-color);
    border-radius: var(--radius-md);
}

.stat-info h3 {
    font-size: 28px;
    margin-bottom: 4px;
}

.stat-info p {
    color: var(--text-secondary);
    font-size: 14px;
}

/* Alerts Section */
.alerts-section {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.alerts-section h2 {
    margin-bottom: 16px;
}

.alerts-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 12px;
}

.alert-tab {
    padding: 8px 16px;
    background: none;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all 0.2s;
}

.alert-tab:hover {
    background: var(--background-color);
}

.alert-tab.active {
    background: var(--primary-color);
    color: white;
}

.alerts-list {
    max-height: 400px;
    overflow-y: auto;
}

.alert-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 16px;
    border-radius: var(--radius-md);
    margin-bottom: 8px;
    background: var(--background-color);
}

.alert-item.urgent {
    background: #fef2f2;
    border-left: 4px solid var(--danger-color);
}

.alert-item.warning {
    background: #fffbeb;
    border-left: 4px solid var(--warning-color);
}

.alert-info h4 {
    font-size: 14px;
    margin-bottom: 4px;
}

.alert-info p {
    font-size: 12px;
    color: var(--text-secondary);
}

.alert-badge {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
}

.alert-badge.urgent {
    background: var(--danger-color);
    color: white;
}

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

.alert-badge.info {
    background: var(--primary-color);
    color: white;
}

.no-alerts {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
}

/* Table Styles */
.table-container {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    overflow-x: auto;
}

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

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

th {
    background: var(--background-color);
    font-weight: 600;
    font-size: 13px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
}

td {
    font-size: 14px;
}

tr:hover {
    background: var(--background-color);
}

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

.actions-cell {
    display: flex;
    gap: 8px;
}

/* Status Badges */
.status-badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
}

.status-badge.active {
    background: #dcfce7;
    color: #166534;
}

.status-badge.completed {
    background: #dbeafe;
    color: #1e40af;
}

.status-badge.on_hold, .status-badge.inactive {
    background: #fef3c7;
    color: #92400e;
}

.status-badge.on_leave {
    background: #f3e8ff;
    color: #7c3aed;
}

.status-badge.expiring {
    background: #fee2e2;
    color: #dc2626;
}

/* Projects Grid */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 20px;
}

.project-card {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: box-shadow 0.2s;
}

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

.project-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 16px;
}

.project-card-header h3 {
    font-size: 16px;
    margin-bottom: 4px;
}

.project-card-header .project-code {
    font-size: 12px;
    color: var(--text-secondary);
}

.project-card-body {
    margin-bottom: 16px;
}

.project-card-body p {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.project-meta {
    display: flex;
    gap: 20px;
    font-size: 12px;
    color: var(--text-secondary);
}

.project-card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.employee-count {
    font-size: 13px;
    color: var(--text-secondary);
}

/* Profile Section */
.profile-container {
    max-width: 800px;
}

.profile-header {
    display: flex;
    align-items: center;
    gap: 24px;
    margin-bottom: 32px;
    padding: 24px;
    background: var(--card-background);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.profile-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 32px;
    font-weight: 600;
}

.profile-info h2 {
    font-size: 24px;
    margin-bottom: 4px;
}

.profile-info p {
    color: var(--text-secondary);
}

.profile-details,
.profile-actions {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    margin-bottom: 20px;
}

.profile-details h3,
.profile-actions h3 {
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border-color);
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--card-background);
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
}

.modal-content.modal-small {
    max-width: 400px;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
    font-size: 18px;
}

.modal-close {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 4px;
    line-height: 1;
}

.modal-close:hover {
    color: var(--text-primary);
}

.modal-content form {
    padding: 24px;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    padding-top: 20px;
    margin-top: 20px;
    border-top: 1px solid var(--border-color);
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: var(--text-primary);
    color: white;
    padding: 14px 24px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    z-index: 2000;
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

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

.toast.error {
    background: var(--danger-color);
}

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

/* Loading Overlay */
.loading-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.8);
    z-index: 3000;
    align-items: center;
    justify-content: center;
}

.loading-overlay.show {
    display: flex;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

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

.empty-state h3 {
    margin-bottom: 8px;
    color: var(--text-primary);
}

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

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

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

    .mobile-menu-btn {
        display: block;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .top-header {
        padding: 0 16px;
    }

    .content-area {
        padding: 16px;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .search-filter {
        flex-direction: column;
    }

    .search-filter input,
    .search-filter select {
        width: 100%;
        max-width: none;
        min-width: 0;
    }

    .section-header {
        flex-direction: column;
        gap: 16px;
        align-items: flex-start;
    }

    .profile-header {
        flex-direction: column;
        text-align: center;
    }

    .alerts-tabs {
        flex-wrap: wrap;
    }

    th, td {
        padding: 10px 12px;
        font-size: 13px;
    }

    .actions-cell {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .login-card {
        padding: 24px;
    }

    .login-header h1 {
        font-size: 24px;
    }

    .stat-card {
        padding: 16px;
    }

    .stat-icon {
        width: 50px;
        height: 50px;
        font-size: 24px;
    }

    .stat-info h3 {
        font-size: 22px;
    }
}

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

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

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

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-color);
}