/**
 * Payroll Application - Modern Premium Styles
 * Features: Dark mode, glassmorphism, smooth animations, responsive design
 */

/* ==================== CSS Variables ==================== */
:root {
  /* Primary Colors - Rich Blue Gradient */
  --primary-50: #eff6ff;
  --primary-100: #dbeafe;
  --primary-200: #bfdbfe;
  --primary-300: #93c5fd;
  --primary-400: #60a5fa;
  --primary-500: #3b82f6;
  --primary-600: #2563eb;
  --primary-700: #1d4ed8;
  --primary-800: #1e40af;
  --primary-900: #1e3a8a;

  /* Accent Colors - Vibrant Purple */
  --accent-400: #c084fc;
  --accent-500: #a855f7;
  --accent-600: #9333ea;

  /* Success, Warning, Error */
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  --info: #06b6d4;

  /* Neutral Colors - Dark Theme */
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;

  /* Background Colors */
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --bg-card: rgba(30, 41, 59, 0.8);
  --bg-glass: rgba(255, 255, 255, 0.05);

  /* Text Colors */
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;

  /* Shadows */
  --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);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  --shadow-glow: 0 0 20px rgba(59, 130, 246, 0.3);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* ==================== Typography ==================== */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: 2.5rem;
  background: linear-gradient(135deg, var(--primary-400), var(--accent-500));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

h2 {
  font-size: 2rem;
  color: var(--text-primary);
}

h3 {
  font-size: 1.5rem;
  color: var(--text-primary);
}

p {
  margin-bottom: var(--spacing-md);
  color: var(--text-secondary);
}

/* ==================== Layout ==================== */
.app-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--spacing-xl);
}

.header {
  text-align: center;
  padding: var(--spacing-2xl) 0;
  margin-bottom: var(--spacing-xl);
}

.header-title {
  font-size: 3rem;
  margin-bottom: var(--spacing-sm);
}

.header-subtitle {
  font-size: 1.125rem;
  color: var(--text-muted);
  font-weight: 400;
}

/* ==================== Navigation Tabs ==================== */
.nav-tabs {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
  background: var(--bg-glass);
  backdrop-filter: blur(10px);
  padding: var(--spacing-sm);
  border-radius: var(--radius-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  overflow-x: auto;
}

.nav-tab {
  flex: 1;
  min-width: 120px;
  padding: var(--spacing-md) var(--spacing-lg);
  background: transparent;
  border: none;
  border-radius: var(--radius-lg);
  color: var(--text-secondary);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.nav-tab::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, var(--primary-600), var(--accent-600));
  opacity: 0;
  transition: opacity var(--transition-base);
  z-index: -1;
}

.nav-tab:hover {
  color: var(--text-primary);
  transform: translateY(-2px);
}

.nav-tab:hover::before {
  opacity: 0.1;
}

.nav-tab.active {
  color: white;
  box-shadow: var(--shadow-glow);
}

.nav-tab.active::before {
  opacity: 1;
}

/* ==================== Cards ==================== */
.card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: var(--shadow-xl);
  transition: all var(--transition-slow);
  margin-bottom: var(--spacing-lg);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  border-color: rgba(255, 255, 255, 0.2);
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.card-title {
  font-size: 1.5rem;
  margin: 0;
}

.card-body {
  color: var(--text-secondary);
}

/* ==================== Grid System ==================== */
.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

/* ==================== Buttons ==================== */
.btn {
  padding: var(--spacing-md) var(--spacing-lg);
  border: none;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-base);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  text-decoration: none;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  transform: translate(-50%, -50%);
  transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary-600), var(--accent-600));
  color: white;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.btn-secondary:hover {
  background: var(--bg-secondary);
  border-color: rgba(255, 255, 255, 0.2);
}

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

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

.btn-sm {
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 0.875rem;
}

.btn-lg {
  padding: var(--spacing-lg) var(--spacing-xl);
  font-size: 1.125rem;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* ==================== Forms ==================== */
.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-label {
  display: block;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
  font-weight: 500;
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: var(--spacing-md);
  background: var(--bg-glass);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-md);
  color: #67717b;
  font-size: 1rem;
  transition: all var(--transition-base);
  backdrop-filter: blur(10px);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--primary-500);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
  background: rgba(255, 255, 255, 0.08);
}

.form-input::placeholder {
  color: var(--text-muted);
}

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

.form-error {
  color: var(--error);
  font-size: 0.875rem;
  margin-top: var(--spacing-xs);
}

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

/* ==================== Table ==================== */
.table-container {
  overflow-x: auto;
  border-radius: var(--radius-lg);
  background: var(--bg-glass);
  backdrop-filter: blur(10px);
}

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

.table thead {
  background: rgba(255, 255, 255, 0.05);
}

.table th {
  padding: var(--spacing-md);
  text-align: left;
  font-weight: 600;
  color: var(--text-primary);
  text-transform: uppercase;
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  border-bottom: 2px solid rgba(255, 255, 255, 0.1);
}

.table td {
  padding: var(--spacing-md);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  color: var(--text-secondary);
}

.table tbody tr {
  transition: all var(--transition-fast);
}

.table tbody tr:hover {
  background: rgba(255, 255, 255, 0.05);
}

/* ==================== Stats Cards ==================== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

.stat-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  border: 1px solid rgba(255, 255, 255, 0.1);
  position: relative;
  overflow: hidden;
}

.stat-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-500), var(--accent-500));
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--spacing-sm);
}

.stat-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
}

.stat-change {
  font-size: 0.875rem;
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

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

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

/* ==================== Modal ==================== */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(5px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: var(--spacing-lg);
  animation: fadeIn var(--transition-base);
}

.modal {
  background: var(--bg-secondary);
  border-radius: var(--radius-xl);
  max-width: 600px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-xl);
  border: 1px solid rgba(255, 255, 255, 0.1);
  animation: slideUp var(--transition-slow);
}

.modal-header {
  padding: var(--spacing-xl);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal-title {
  font-size: 1.5rem;
  margin: 0;
}

.modal-close {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.5rem;
  cursor: pointer;
  padding: var(--spacing-sm);
  transition: color var(--transition-fast);
}

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

.modal-body {
  padding: var(--spacing-xl);
}

.modal-footer {
  padding: var(--spacing-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  gap: var(--spacing-md);
  justify-content: flex-end;
}

/* ==================== Alerts ==================== */
.alert {
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  animation: slideDown var(--transition-base);
}

.alert-success {
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid var(--success);
  color: var(--success);
}

.alert-error {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid var(--error);
  color: var(--error);
}

.alert-warning {
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid var(--warning);
  color: var(--warning);
}

.alert-info {
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid var(--info);
  color: var(--info);
}

/* ==================== Utilities ==================== */
.hidden {
  display: none !important;
}

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.mt-0 {
  margin-top: 0;
}

.mt-1 {
  margin-top: var(--spacing-sm);
}

.mt-2 {
  margin-top: var(--spacing-md);
}

.mt-3 {
  margin-top: var(--spacing-lg);
}

.mt-4 {
  margin-top: var(--spacing-xl);
}

.mb-0 {
  margin-bottom: 0;
}

.mb-1 {
  margin-bottom: var(--spacing-sm);
}

.mb-2 {
  margin-bottom: var(--spacing-md);
}

.mb-3 {
  margin-bottom: var(--spacing-lg);
}

.mb-4 {
  margin-bottom: var(--spacing-xl);
}

/* ==================== Animations ==================== */
@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ==================== Responsive Design ==================== */
@media (max-width: 768px) {
  .app-container {
    padding: var(--spacing-md);
  }

  .header-title {
    font-size: 2rem;
  }

  .nav-tabs {
    flex-direction: column;
  }

  .nav-tab {
    width: 100%;
  }

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

  .modal {
    margin: var(--spacing-md);
  }

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

/* ==================== Print Styles ==================== */
@media print {
  body {
    background: white;
    color: black;
  }

  .nav-tabs,
  .btn,
  .modal-close {
    display: none !important;
  }

  .card {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ddd;
  }
}