/* ============================================
   TUTORCONNECT - Main Stylesheet
   ============================================ */

/* CSS Variables */
:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #dbeafe;
    --color-success: #10b981;
    --color-success-light: #d1fae5;
    --color-warning: #f59e0b;
    --color-warning-light: #fef3c7;
    --color-danger: #ef4444;
    --color-danger-light: #fee2e2;
    --color-gray-50: #f9fafb;
    --color-gray-100: #f3f4f6;
    --color-gray-200: #e5e7eb;
    --color-gray-300: #d1d5db;
    --color-gray-400: #9ca3af;
    --color-gray-500: #6b7280;
    --color-gray-600: #4b5563;
    --color-gray-700: #374151;
    --color-gray-800: #1f2937;
    --color-gray-900: #111827;

    --sidebar-width: 260px;
    --header-height: 64px;

    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);

    --radius-sm: 0.25rem;
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --radius-xl: 0.75rem;
}

/* Reset */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-size: 0.875rem;
    line-height: 1.5;
    color: var(--color-gray-800);
    background-color: var(--color-gray-50);
}

a {
    color: var(--color-primary);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

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

/* Sidebar */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    width: var(--sidebar-width);
    background: white;
    border-right: 1px solid var(--color-gray-200);
    display: flex;
    flex-direction: column;
    z-index: 100;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--color-gray-200);
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    font-size: 16px;
}

.logo-text {
    font-size: 18px;
    font-weight: 700;
    color: var(--color-gray-900);
}

.sidebar-nav {
    flex: 1;
    padding: 16px 12px;
    overflow-y: auto;
}

.nav-section {
    margin-bottom: 24px;
}

.nav-section-title {
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--color-gray-500);
    padding: 8px 12px;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 12px;
    color: var(--color-gray-600);
    border-radius: var(--radius-md);
    transition: all 0.15s ease;
    text-decoration: none;
    font-weight: 500;
}

.nav-link:hover {
    background: var(--color-gray-100);
    color: var(--color-gray-900);
    text-decoration: none;
}

.nav-link.active {
    background: var(--color-primary-light);
    color: var(--color-primary);
}

.nav-link svg {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.nav-badge {
    margin-left: auto;
    background: var(--color-danger);
    color: white;
    font-size: 11px;
    font-weight: 600;
    padding: 2px 8px;
    border-radius: 10px;
}

.sidebar-footer {
    padding: 16px 20px;
    border-top: 1px solid var(--color-gray-200);
}

.user-info {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-avatar {
    width: 36px;
    height: 36px;
    background: var(--color-primary-light);
    color: var(--color-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 14px;
}

.user-details {
    flex: 1;
    min-width: 0;
}

.user-name {
    font-weight: 600;
    color: var(--color-gray-900);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.user-role {
    font-size: 12px;
    color: var(--color-gray-500);
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
}

/* Header */
.header {
    height: var(--header-height);
    background: white;
    border-bottom: 1px solid var(--color-gray-200);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    position: sticky;
    top: 0;
    z-index: 50;
}

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

.page-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--color-gray-900);
}

.breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    color: var(--color-gray-500);
}

.breadcrumb a {
    color: var(--color-gray-500);
}

.breadcrumb a:hover {
    color: var(--color-primary);
}

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

.search-box {
    position: relative;
}

.search-box input {
    width: 280px;
    padding: 8px 12px 8px 36px;
    border: 1px solid var(--color-gray-300);
    border-radius: var(--radius-md);
    font-size: 13px;
    transition: all 0.15s ease;
}

.search-box input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

.search-box svg {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    width: 16px;
    height: 16px;
    color: var(--color-gray-400);
}

.header-btn {
    width: 36px;
    height: 36px;
    border: none;
    background: transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gray-500);
    transition: all 0.15s ease;
    position: relative;
}

.header-btn:hover {
    background: var(--color-gray-100);
    color: var(--color-gray-700);
}

.header-btn .badge {
    position: absolute;
    top: 4px;
    right: 4px;
    width: 8px;
    height: 8px;
    background: var(--color-danger);
    border-radius: 50%;
}

/* Page Content */
.page-content {
    flex: 1;
    padding: 24px;
}

/* Cards */
.card {
    background: white;
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.card-header {
    padding: 16px 20px;
    border-bottom: 1px solid var(--color-gray-200);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.card-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--color-gray-900);
}

.card-body {
    padding: 20px;
}

.card-footer {
    padding: 16px 20px;
    border-top: 1px solid var(--color-gray-200);
    background: var(--color-gray-50);
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
}

/* Stats Cards */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin-bottom: 24px;
}

.stat-card {
    background: white;
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-lg);
    padding: 20px;
    display: flex;
    align-items: flex-start;
    gap: 16px;
}

.stat-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.stat-icon.blue {
    background: var(--color-primary-light);
    color: var(--color-primary);
}

.stat-icon.green {
    background: var(--color-success-light);
    color: var(--color-success);
}

.stat-icon.yellow {
    background: var(--color-warning-light);
    color: var(--color-warning);
}

.stat-icon.red {
    background: var(--color-danger-light);
    color: var(--color-danger);
}

.stat-icon svg {
    width: 24px;
    height: 24px;
}

.stat-content {
    flex: 1;
}

.stat-label {
    font-size: 13px;
    color: var(--color-gray-500);
    margin-bottom: 4px;
}

.stat-value {
    font-size: 28px;
    font-weight: 700;
    color: var(--color-gray-900);
    line-height: 1.2;
}

.stat-change {
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 12px;
    margin-top: 4px;
}

.stat-change.positive {
    color: var(--color-success);
}

.stat-change.negative {
    color: var(--color-danger);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 8px 16px;
    font-size: 14px;
    font-weight: 500;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all 0.15s ease;
    text-decoration: none;
}

.btn:hover {
    text-decoration: none;
}

.btn svg {
    width: 18px;
    height: 18px;
}

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

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

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

.btn-secondary:hover {
    background: var(--color-gray-50);
    border-color: var(--color-gray-400);
}

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

.btn-success:hover {
    background: #059669;
}

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

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

.btn-sm {
    padding: 6px 12px;
    font-size: 13px;
}

.btn-sm svg {
    width: 16px;
    height: 16px;
}

.btn-lg {
    padding: 12px 24px;
    font-size: 16px;
}

.btn-icon {
    padding: 8px;
}

.btn-icon svg {
    width: 20px;
    height: 20px;
}

/* Forms */
.form-group {
    margin-bottom: 16px;
}

.form-label {
    display: block;
    font-size: 13px;
    font-weight: 500;
    color: var(--color-gray-700);
    margin-bottom: 6px;
}

.form-label.required::after {
    content: '*';
    color: var(--color-danger);
    margin-left: 4px;
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--color-gray-300);
    border-radius: var(--radius-md);
    font-size: 14px;
    font-family: inherit;
    transition: all 0.15s ease;
    background: white;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

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

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

.form-hint {
    font-size: 12px;
    color: var(--color-gray-500);
    margin-top: 4px;
}

.form-error {
    font-size: 12px;
    color: var(--color-danger);
    margin-top: 4px;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

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

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

.table th,
.table td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--color-gray-200);
}

.table th {
    font-weight: 600;
    color: var(--color-gray-700);
    background: var(--color-gray-50);
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.table td {
    color: var(--color-gray-600);
}

.table tbody tr:hover {
    background: var(--color-gray-50);
}

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

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    font-size: 12px;
    font-weight: 500;
    border-radius: 20px;
}

.badge-primary {
    background: var(--color-primary-light);
    color: var(--color-primary);
}

.badge-success {
    background: var(--color-success-light);
    color: #065f46;
}

.badge-warning {
    background: var(--color-warning-light);
    color: #92400e;
}

.badge-danger {
    background: var(--color-danger-light);
    color: #991b1b;
}

.badge-gray {
    background: var(--color-gray-100);
    color: var(--color-gray-600);
}

/* Kanban Board */
.kanban-board {
    display: flex;
    gap: 16px;
    overflow-x: auto;
    padding-bottom: 16px;
}

.kanban-column {
    flex: 0 0 300px;
    background: var(--color-gray-100);
    border-radius: var(--radius-lg);
    display: flex;
    flex-direction: column;
    max-height: calc(100vh - 280px);
}

.kanban-column-header {
    padding: 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--color-gray-200);
}

.kanban-column-title {
    font-weight: 600;
    color: var(--color-gray-900);
    display: flex;
    align-items: center;
    gap: 8px;
}

.kanban-column-count {
    background: var(--color-gray-300);
    color: var(--color-gray-700);
    font-size: 12px;
    padding: 2px 8px;
    border-radius: 10px;
}

.kanban-column-body {
    flex: 1;
    overflow-y: auto;
    padding: 12px;
}

.kanban-card {
    background: white;
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-md);
    padding: 14px;
    margin-bottom: 10px;
    cursor: pointer;
    transition: all 0.15s ease;
}

.kanban-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--color-gray-300);
}

.kanban-card:last-child {
    margin-bottom: 0;
}

.kanban-card-title {
    font-weight: 500;
    color: var(--color-gray-900);
    margin-bottom: 8px;
}

.kanban-card-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 12px;
    color: var(--color-gray-500);
}

.kanban-card-meta svg {
    width: 14px;
    height: 14px;
}

.kanban-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid var(--color-gray-100);
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.2s ease;
}

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

.modal {
    background: white;
    border-radius: var(--radius-xl);
    width: 100%;
    max-width: 560px;
    max-height: 90vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    transform: scale(0.95);
    transition: transform 0.2s ease;
}

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

.modal-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--color-gray-200);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.modal-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--color-gray-900);
}

.modal-close {
    width: 32px;
    height: 32px;
    border: none;
    background: transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gray-500);
    transition: all 0.15s ease;
}

.modal-close:hover {
    background: var(--color-gray-100);
    color: var(--color-gray-700);
}

.modal-body {
    padding: 24px;
    overflow-y: auto;
}

.modal-footer {
    padding: 16px 24px;
    border-top: 1px solid var(--color-gray-200);
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 12px;
    background: var(--color-gray-50);
}

/* Dropdown */
.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 4px;
    background: white;
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    min-width: 180px;
    z-index: 100;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: all 0.15s ease;
}

.dropdown.active .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 14px;
    color: var(--color-gray-700);
    font-size: 14px;
    cursor: pointer;
    transition: background 0.15s ease;
}

.dropdown-item:hover {
    background: var(--color-gray-50);
}

.dropdown-item svg {
    width: 18px;
    height: 18px;
    color: var(--color-gray-500);
}

.dropdown-divider {
    height: 1px;
    background: var(--color-gray-200);
    margin: 4px 0;
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    bottom: 24px;
    right: 24px;
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.toast {
    background: white;
    border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-md);
    padding: 16px 20px;
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: flex-start;
    gap: 12px;
    min-width: 320px;
    max-width: 420px;
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.toast-icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

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

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

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

.toast-content {
    flex: 1;
}

.toast-title {
    font-weight: 600;
    color: var(--color-gray-900);
    margin-bottom: 2px;
}

.toast-message {
    font-size: 13px;
    color: var(--color-gray-600);
}

.toast-close {
    width: 20px;
    height: 20px;
    border: none;
    background: transparent;
    cursor: pointer;
    color: var(--color-gray-400);
    padding: 0;
}

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

/* Empty State */
.empty-state {
    text-align: center;
    padding: 48px 24px;
}

.empty-state-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 16px;
    color: var(--color-gray-300);
}

.empty-state-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--color-gray-900);
    margin-bottom: 8px;
}

.empty-state-description {
    color: var(--color-gray-500);
    margin-bottom: 24px;
}

/* Loading Spinner */
.spinner {
    width: 24px;
    height: 24px;
    border: 3px solid var(--color-gray-200);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 3000;
}

/* Utility Classes */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-muted { color: var(--color-gray-500); }
.text-success { color: var(--color-success); }
.text-danger { color: var(--color-danger); }
.text-warning { color: var(--color-warning); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 0.75rem; }
.mb-4 { margin-bottom: 1rem; }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 0.75rem; }
.mt-4 { margin-top: 1rem; }

.d-flex { display: flex; }
.align-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-1 { gap: 0.25rem; }
.gap-2 { gap: 0.5rem; }
.gap-3 { gap: 0.75rem; }
.gap-4 { gap: 1rem; }

.hidden { display: none !important; }

/* Responsive */
@media (max-width: 1024px) {
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.3s ease;
    }

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

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

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

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

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

    .header-right .search-box {
        display: none;
    }

    .kanban-column {
        flex: 0 0 280px;
    }
}