/* ============================================================
   Academic Service Management System - Main Stylesheet
   ============================================================ */

:root {
  --primary: #2563EB;
  --primary-dark: #1D4ED8;
  --primary-light: #3B82F6;
  --sidebar-bg: #0F172A;
  --sidebar-hover: #1E293B;
  --bg-light: #F8FAFC;
  --text-dark: #0F172A;
  --text-muted: #64748B;
  --card-shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --card-hover-shadow: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  --transition: all 0.3s ease;
}

/* Dark Mode Variables */
[data-theme="dark"] {
  --sidebar-bg: #0B1121;
  --sidebar-hover: #1a2332;
  --bg-light: #0F172A;
  --text-dark: #F1F5F9;
  --text-muted: #94A3B8;
  --card-shadow: 0 1px 3px rgba(0,0,0,0.3);
  --card-hover-shadow: 0 10px 15px -3px rgba(0,0,0,0.3);
}

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

body {
  font-family: 'Sarabun', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: var(--bg-light);
  color: var(--text-dark);
  transition: var(--transition);
  overflow-x: hidden;
}

/* ==================== Sidebar ==================== */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: 260px;
  height: 100vh;
  background: var(--sidebar-bg);
  color: #fff;
  z-index: 1000;
  transition: var(--transition);
  overflow-y: auto;
}

.sidebar .sidebar-header {
  padding: 20px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}

.sidebar .sidebar-header h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
}

.sidebar .sidebar-header .subtitle {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 2px;
}

.sidebar .nav-item {
  padding: 12px 20px;
  color: rgba(255,255,255,0.7);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: var(--transition);
  cursor: pointer;
  border-left: 3px solid transparent;
}

.sidebar .nav-item:hover,
.sidebar .nav-item.active {
  background: var(--sidebar-hover);
  color: #fff;
  border-left-color: var(--primary);
}

.sidebar .nav-item i {
  width: 20px;
  text-align: center;
  font-size: 1.1rem;
}

.sidebar .nav-item .badge {
  margin-left: auto;
}

/* ==================== Main Content ==================== */
.main-content {
  margin-left: 260px;
  min-height: 100vh;
  transition: var(--transition);
}

/* ==================== Navbar ==================== */
.navbar-custom {
  background: #fff;
  padding: 12px 24px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 999;
}

[data-theme="dark"] .navbar-custom {
  background: #1E293B;
}

.navbar-custom .page-title {
  font-size: 1.25rem;
  font-weight: 600;
}

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

.navbar-custom .user-info {
  display: flex;
  align-items: center;
  gap: 10px;
}

.navbar-custom .user-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.9rem;
}

/* ==================== Cards ==================== */
.stat-card {
  background: #fff;
  border-radius: 12px;
  padding: 20px;
  box-shadow: var(--card-shadow);
  transition: var(--transition);
  border: none;
}

[data-theme="dark"] .stat-card {
  background: #1E293B;
}

.stat-card:hover {
  box-shadow: var(--card-hover-shadow);
  transform: translateY(-2px);
}

.stat-card .stat-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.stat-card .stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.stat-card .stat-value {
  font-size: 1.75rem;
  font-weight: 700;
}

/* ==================== Charts ==================== */
.chart-container {
  background: #fff;
  border-radius: 12px;
  padding: 20px;
  box-shadow: var(--card-shadow);
  margin-bottom: 24px;
}

[data-theme="dark"] .chart-container {
  background: #1E293B;
}

.chart-container .chart-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text-dark);
}

/* ==================== Tables ==================== */
.table-container {
  background: #fff;
  border-radius: 12px;
  padding: 20px;
  box-shadow: var(--card-shadow);
}

[data-theme="dark"] .table-container {
  background: #1E293B;
}

.table-container .table-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
  flex-wrap: wrap;
  gap: 12px;
}

.table-container .table-title {
  font-size: 1.1rem;
  font-weight: 600;
}

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

.data-table th {
  background: var(--bg-light);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  padding: 12px;
  text-align: left;
  font-weight: 600;
}

[data-theme="dark"] .data-table th {
  background: #0F172A;
}

.data-table td {
  padding: 12px;
  border-bottom: 1px solid rgba(0,0,0,0.05);
  font-size: 0.9rem;
}

[data-theme="dark"] .data-table td {
  border-bottom-color: rgba(255,255,255,0.05);
}

.data-table tr:hover {
  background: rgba(37,99,235,0.03);
}

/* ==================== Login Page ==================== */
.login-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--sidebar-bg) 0%, #1e3a5f 100%);
  padding: 20px;
}

.login-card {
  background: #fff;
  border-radius: 16px;
  padding: 40px;
  width: 100%;
  max-width: 420px;
  box-shadow: 0 25px 50px -12px rgba(0,0,0,0.25);
}

[data-theme="dark"] .login-card {
  background: #1E293B;
}

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

.login-card .login-logo h2 {
  font-weight: 700;
  color: var(--primary);
}

.login-card .login-logo p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 4px;
}

/* ==================== Forms ==================== */
.form-control, .form-select {
  border-radius: 8px;
  padding: 10px 14px;
  border: 1px solid #E2E8F0;
  transition: var(--transition);
}

.form-control:focus, .form-select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.15);
}

[data-theme="dark"] .form-control, [data-theme="dark"] .form-select {
  background: #0F172A;
  border-color: #334155;
  color: #fff;
}

/* ==================== Buttons ==================== */
.btn-primary {
  background: var(--primary);
  border: none;
  border-radius: 8px;
  padding: 10px 20px;
  font-weight: 500;
  transition: var(--transition);
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
}

.btn-outline-primary {
  border-color: var(--primary);
  color: var(--primary);
  border-radius: 8px;
}

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

/* ==================== Modal ==================== */
.modal-content {
  border-radius: 12px;
  border: none;
}

[data-theme="dark"] .modal-content {
  background: #1E293B;
  color: #fff;
}

.modal-header {
  border-bottom: 1px solid #E2E8F0;
  padding: 20px;
}

[data-theme="dark"] .modal-header {
  border-bottom-color: #334155;
}

.modal-footer {
  border-top: 1px solid #E2E8F0;
  padding: 16px 20px;
}

[data-theme="dark"] .modal-footer {
  border-top-color: #334155;
}

/* ==================== Dark Mode Toggle ==================== */
.dark-mode-toggle {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.2rem;
  cursor: pointer;
  padding: 8px;
  border-radius: 8px;
  transition: var(--transition);
}

.dark-mode-toggle:hover {
  background: rgba(0,0,0,0.05);
  color: var(--text-dark);
}

[data-theme="dark"] .dark-mode-toggle:hover {
  background: rgba(255,255,255,0.1);
  color: #fff;
}

/* ==================== Responsive ==================== */
@media (max-width: 992px) {
  .sidebar {
    transform: translateX(-100%);
  }

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

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

  .sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: 999;
  }

  .sidebar-overlay.show {
    display: block;
  }
}

@media (max-width: 768px) {
  .stat-card .stat-value {
    font-size: 1.3rem;
  }

  .table-container .table-header {
    flex-direction: column;
    align-items: stretch;
  }

  .navbar-custom {
    padding: 10px 16px;
  }

  .navbar-custom .page-title {
    font-size: 1rem;
  }
}

/* ==================== Loading Spinner ==================== */
.loading-overlay {
  position: fixed;
  inset: 0;
  background: rgba(255,255,255,0.8);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
}

[data-theme="dark"] .loading-overlay {
  background: rgba(15,23,42,0.8);
}

.spinner-custom {
  width: 48px;
  height: 48px;
  border: 4px solid #E2E8F0;
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* ==================== Profile Dropdown ==================== */
.profile-dropdown .dropdown-menu {
  border-radius: 12px;
  border: none;
  box-shadow: 0 10px 30px rgba(0,0,0,0.15);
  padding: 8px;
}

.profile-dropdown .dropdown-item {
  border-radius: 8px;
  padding: 8px 12px;
  transition: var(--transition);
}

.profile-dropdown .dropdown-item:hover {
  background: rgba(37,99,235,0.08);
  color: var(--primary);
}

/* ==================== File Upload ==================== */
.upload-area {
  border: 2px dashed #CBD5E1;
  border-radius: 12px;
  padding: 40px;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
}

.upload-area:hover {
  border-color: var(--primary);
  background: rgba(37,99,235,0.03);
}

.upload-area i {
  font-size: 2.5rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

/* ==================== Pagination ==================== */
.pagination-custom .page-item .page-link {
  border-radius: 8px;
  margin: 0 2px;
  border: none;
  color: var(--text-dark);
  padding: 8px 14px;
  transition: var(--transition);
}

.pagination-custom .page-item.active .page-link {
  background: var(--primary);
  color: #fff;
}

.pagination-custom .page-item .page-link:hover {
  background: rgba(37,99,235,0.1);
}

/* ==================== Scrollbar ==================== */
::-webkit-scrollbar {
  width: 6px;
}

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

::-webkit-scrollbar-thumb {
  background: #CBD5E1;
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: #94A3B8;
}