/* ==========================================================================
   DESIGN SYSTEM - BILIM AKADEMI COURSE MANAGEMENT & PRE-ACCOUNTING
   ========================================================================== */

/* Theme Variables */
:root {
  /* Light Mode Variables */
  --primary-hue: 215;
  --primary: hsl(var(--primary-hue), 85%, 55%);
  --primary-hover: hsl(var(--primary-hue), 85%, 45%);
  --primary-light: hsl(var(--primary-hue), 85%, 95%);
  --primary-light-hover: hsl(var(--primary-hue), 85%, 90%);
  
  --secondary: hsl(260, 60%, 60%);
  --success: hsl(145, 65%, 40%);
  --success-light: hsl(145, 65%, 95%);
  --warning: hsl(38, 90%, 50%);
  --warning-light: hsl(38, 90%, 95%);
  --danger: hsl(355, 75%, 55%);
  --danger-light: hsl(355, 75%, 95%);
  
  --bg-app: hsl(210, 40%, 97%);
  --bg-sidebar: hsl(215, 60%, 15%);
  --bg-card: hsl(0, 0%, 100%);
  --bg-input: hsl(210, 20%, 98%);
  --bg-header: hsla(0, 0%, 100%, 0.85);
  
  --text-main: hsl(215, 30%, 20%);
  --text-muted: hsl(215, 15%, 50%);
  --text-light: hsl(215, 15%, 95%);
  
  --border-color: hsl(215, 20%, 90%);
  --border-focus: hsl(var(--primary-hue), 85%, 75%);
  
  --shadow-sm: 0 2px 4px rgba(0,0,0,0.02);
  --shadow-md: 0 8px 16px rgba(10,30,60,0.05);
  --shadow-lg: 0 16px 32px rgba(10,30,60,0.1);
  --shadow-inset: inset 0 2px 4px rgba(0,0,0,0.05);
  
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  
  --sidebar-width: 260px;
  --header-height: 70px;
}

/* Dark Mode Variables */
body.dark-mode {
  --bg-app: hsl(220, 25%, 8%);
  --bg-sidebar: hsl(220, 30%, 6%);
  --bg-card: hsl(220, 20%, 12%);
  --bg-input: hsl(220, 20%, 15%);
  --bg-header: hsla(220, 25%, 8%, 0.85);
  
  --text-main: hsl(210, 25%, 88%);
  --text-muted: hsl(210, 10%, 60%);
  
  --border-color: hsl(220, 20%, 18%);
  
  --shadow-md: 0 8px 16px rgba(0,0,0,0.25);
  --shadow-lg: 0 16px 32px rgba(0,0,0,0.35);
}

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

body {
  font-family: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-app);
  color: var(--text-main);
  overflow-x: hidden;
  line-height: 1.5;
  transition: background-color 0.3s ease, color 0.3s ease;
}

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

/* Sidebar Styling */
.app-sidebar {
  width: var(--sidebar-width);
  background-color: var(--bg-sidebar);
  color: var(--text-light);
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  z-index: 100;
  transition: var(--transition);
  box-shadow: 4px 0 24px rgba(0, 0, 0, 0.15);
}

.sidebar-brand {
  padding: 24px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.brand-logo {
  width: 42px;
  height: 42px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  color: #fff;
  box-shadow: 0 4px 12px rgba(0, 100, 250, 0.3);
}

.brand-info h2 {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.brand-info span {
  font-size: 11px;
  color: rgba(255, 255, 255, 0.4);
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 0.5px;
}

.sidebar-nav {
  flex: 1;
  padding: 24px 12px;
  overflow-y: auto;
}

.sidebar-nav ul {
  list-style: none;
}

.sidebar-nav li {
  margin-bottom: 6px;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 12px 16px;
  color: rgba(255, 255, 255, 0.65);
  text-decoration: none;
  font-weight: 500;
  font-size: 14px;
  border-radius: var(--radius-md);
  transition: var(--transition);
}

.nav-link i {
  font-size: 16px;
  width: 20px;
  text-align: center;
  transition: var(--transition);
}

.nav-link:hover {
  background-color: rgba(255, 255, 255, 0.05);
  color: #fff;
}

.nav-link.active {
  background-color: var(--primary);
  color: #fff;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(0, 100, 250, 0.2);
}

.nav-link.active i {
  transform: scale(1.1);
}

.sidebar-footer {
  padding: 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.user-profile {
  display: flex;
  align-items: center;
  gap: 12px;
  background-color: rgba(255, 255, 255, 0.04);
  padding: 12px;
  border-radius: var(--radius-md);
}

.user-avatar {
  width: 36px;
  height: 36px;
  background-color: var(--primary);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 15px;
  color: #fff;
}

.user-meta h4 {
  font-size: 13px;
  font-weight: 600;
}

.user-meta span {
  font-size: 10px;
  color: rgba(255, 255, 255, 0.4);
}

/* Main Area Wrapper & Header */
.app-main-wrapper {
  flex: 1;
  margin-left: var(--sidebar-width);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
}

.app-header {
  height: var(--header-height);
  background-color: var(--bg-header);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-color);
  padding: 0 30px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 90;
  transition: var(--transition);
}

.header-left {
  display: flex;
  align-items: center;
  gap: 20px;
}

.toggle-sidebar-btn {
  background: none;
  border: none;
  color: var(--text-main);
  font-size: 20px;
  cursor: pointer;
  display: none;
}

.branch-selector-wrapper {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-muted);
}

.branch-selector-wrapper i {
  color: var(--primary);
}

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

.season-badge {
  background-color: var(--primary-light);
  color: var(--primary);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  font-size: 13px;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 6px;
}

.theme-toggle-btn,
.notification-btn {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-color);
  background-color: var(--bg-card);
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  transition: var(--transition);
  position: relative;
}

.theme-toggle-btn:hover,
.notification-btn:hover {
  background-color: var(--bg-input);
  border-color: var(--text-muted);
}

.notification-btn .badge {
  position: absolute;
  top: -2px;
  right: -2px;
  background-color: var(--danger);
  color: #fff;
  border: 2px solid var(--bg-card);
  border-radius: var(--radius-full);
  width: 18px;
  height: 18px;
  font-size: 10px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.vertical-divider {
  width: 1px;
  height: 24px;
  background-color: var(--border-color);
}

.header-user {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 14px;
}

.user-status-dot {
  width: 8px;
  height: 8px;
  background-color: var(--success);
  border-radius: var(--radius-full);
  box-shadow: 0 0 8px var(--success);
}

/* App Viewport / Pages */
.app-content {
  flex: 1;
  padding: 30px;
}

/* Page Components styling */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}

.page-title-group h1 {
  font-size: 26px;
  font-weight: 700;
  letter-spacing: -0.5px;
  margin-bottom: 4px;
}

.page-title-group p {
  font-size: 14px;
  color: var(--text-muted);
}

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

.form-group label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.form-control {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border-color);
  background-color: var(--bg-input);
  color: var(--text-main);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 14px;
  transition: var(--transition);
}

.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(0, 100, 250, 0.15);
}

.select-minimal {
  padding-right: 24px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  background-size: 14px;
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  text-decoration: none;
}

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

.btn-primary:hover {
  background-color: var(--primary-hover);
  box-shadow: 0 4px 12px rgba(0, 100, 250, 0.2);
}

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

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

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

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

.btn-sm {
  padding: 6px 12px;
  font-size: 12px;
  border-radius: var(--radius-sm);
}

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

.stat-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 24px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: var(--transition);
}

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

.stat-info h3 {
  font-size: 13px;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.5px;
  font-weight: 600;
}

.stat-value-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 6px;
}

.stat-value {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.stat-icon {
  width: 50px;
  height: 50px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
}

.stat-icon.primary { background-color: var(--primary-light); color: var(--primary); }
.stat-icon.secondary { background-color: hsl(260, 60%, 95%); color: var(--secondary); }
.stat-icon.success { background-color: var(--success-light); color: var(--success); }
.stat-icon.danger { background-color: var(--danger-light); color: var(--danger); }

/* Dashboard Cards & Layout */
.grid-dashboard-main {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 30px;
}

.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  margin-bottom: 24px;
  overflow: hidden;
}

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

.card-title {
  font-size: 16px;
  font-weight: 700;
}

.card-body {
  padding: 24px;
}

/* Tables & Lists */
.table-responsive {
  width: 100%;
  overflow-x: auto;
}

.table-custom {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 14px;
}

.table-custom th {
  padding: 14px 16px;
  font-weight: 600;
  color: var(--text-muted);
  border-bottom: 2px solid var(--border-color);
}

.table-custom td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--border-color);
  vertical-align: middle;
}

.table-custom tbody tr:hover {
  background-color: var(--bg-input);
}

/* Badges */
.badge-ui {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  font-size: 11px;
  font-weight: 600;
}

.badge-ui.success { background-color: var(--success-light); color: var(--success); }
.badge-ui.warning { background-color: var(--warning-light); color: var(--warning); }
.badge-ui.danger { background-color: var(--danger-light); color: var(--danger); }
.badge-ui.primary { background-color: var(--primary-light); color: var(--primary); }

/* Modals */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(4px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-container {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  width: 90%;
  max-width: 600px;
  max-height: 85vh;
  box-shadow: var(--shadow-lg);
  display: flex;
  flex-direction: column;
  transform: translateY(20px);
  transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.modal-header {
  padding: 18px 24px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.close-modal-btn {
  background: none;
  border: none;
  font-size: 24px;
  color: var(--text-muted);
  cursor: pointer;
}

.modal-body {
  padding: 24px;
  overflow-y: auto;
  flex: 1;
}

/* Tabs */
.tab-container {
  margin-bottom: 20px;
}

.tab-nav {
  display: flex;
  border-bottom: 1px solid var(--border-color);
  gap: 12px;
  list-style: none;
  margin-bottom: 20px;
  overflow-x: auto;
}

.tab-btn {
  padding: 12px 16px;
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  color: var(--text-muted);
  border-bottom: 2px solid transparent;
  background: none;
  border: none;
  transition: var(--transition);
  white-space: nowrap;
}

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

.tab-btn.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

.tab-pane {
  display: none;
}

.tab-pane.active {
  display: block;
}

/* Filter controls bar */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  background-color: var(--bg-card);
  padding: 16px 20px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  margin-bottom: 20px;
  align-items: center;
}

.filter-item {
  min-width: 140px;
}

.filter-search {
  flex: 1;
  min-width: 200px;
}

/* Calendar styling */
.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 8px;
}

.calendar-header {
  font-weight: 600;
  text-align: center;
  padding: 8px;
  color: var(--text-muted);
}

.calendar-day {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  aspect-ratio: 1.2;
  padding: 8px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
  transition: var(--transition);
}

.calendar-day:hover {
  background-color: var(--bg-input);
}

.calendar-day.empty {
  background-color: transparent;
  border-color: transparent;
  pointer-events: none;
}

.calendar-day .day-num {
  font-weight: 600;
  font-size: 12px;
}

.calendar-events {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.calendar-event {
  font-size: 10px;
  padding: 2px 4px;
  border-radius: var(--radius-sm);
  background-color: var(--primary-light);
  color: var(--primary);
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Spinner */
.spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--border-color);
  border-top-color: var(--primary);
  border-radius: var(--radius-full);
  animation: spin 1s linear infinite;
}

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

.page-loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 60px 0;
  color: var(--text-muted);
}

/* Notification Dropdown toggles */
.notification-dropdown {
  position: absolute;
  top: 48px;
  right: 0;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  width: 320px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  display: none;
  z-index: 150;
  overflow: hidden;
}

.notification-dropdown.active {
  display: block;
}

.dropdown-header {
  padding: 12px 16px;
  font-weight: 600;
  border-bottom: 1px solid var(--border-color);
}

.dropdown-body {
  max-height: 250px;
  overflow-y: auto;
}

.notification-item {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-color);
  font-size: 13px;
  cursor: pointer;
  transition: var(--transition);
}

.notification-item:hover {
  background-color: var(--bg-input);
}

.notification-item:last-child {
  border-bottom: none;
}

.empty-state {
  padding: 20px;
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
}

/* Responsive adjustments */
@media (max-width: 992px) {
  .app-sidebar {
    left: calc(-1 * var(--sidebar-width));
  }
  .app-sidebar.active {
    left: 0;
  }
  .app-main-wrapper {
    margin-left: 0;
  }
  .toggle-sidebar-btn {
    display: block;
  }
  .grid-dashboard-main {
    grid-template-columns: 1fr;
  }
}

/* ==========================================================================
   AUTHENTICATION STYLING (LOGIN SCREEN)
   ========================================================================== */
.login-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, hsl(215, 60%, 15%), hsl(220, 25%, 8%));
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10000;
  opacity: 1;
  pointer-events: auto;
  transition: opacity 0.3s ease;
}

.login-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.login-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 40px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 400px;
}

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

.brand-logo-login {
  width: 54px;
  height: 54px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: var(--radius-md);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  color: #fff;
  margin-bottom: 12px;
  box-shadow: 0 4px 12px rgba(0, 100, 250, 0.3);
}

.login-brand h2 {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.5px;
  margin-bottom: 4px;
  color: var(--text-main);
}

.login-brand span {
  font-size: 12px;
  color: var(--text-muted);
  font-weight: 500;
}