/**
 * Enterprise Payroll Management System - Design System
 * Version 8.0.0 - Professional UI Redesign
 * 
 * A modern, clean, enterprise-grade design system
 * Following 2024+ best practices
 */

/* ============================================================================
   CSS VARIABLES - DESIGN TOKENS
   ============================================================================ */
:root {
  /* Brand Colors - Professional Blue Theme */
  --color-primary: #1e40af;        /* Deep Blue */
  --color-primary-dark: #1e3a8a;   /* Darker Blue */
  --color-primary-light: #3b82f6;  /* Lighter Blue */
  --color-primary-pale: #dbeafe;   /* Very Light Blue */
  
  /* Neutral Colors */
  --color-gray-900: #0f172a;       /* Headings */
  --color-gray-800: #1e293b;       /* Body Text */
  --color-gray-700: #334155;       /* Secondary Text */
  --color-gray-600: #475569;       /* Muted Text */
  --color-gray-500: #64748b;       /* Disabled Text */
  --color-gray-400: #94a3b8;       /* Borders */
  --color-gray-300: #cbd5e1;       /* Light Borders */
  --color-gray-200: #e2e8f0;       /* Backgrounds */
  --color-gray-100: #f1f5f9;       /* Subtle Backgrounds */
  --color-gray-50: #f8fafc;        /* Page Background */
  
  /* Semantic Colors */
  --color-success: #059669;        /* Green */
  --color-success-light: #d1fae5;  
  --color-danger: #dc2626;         /* Red */
  --color-danger-light: #fee2e2;
  --color-warning: #d97706;        /* Amber */
  --color-warning-light: #fef3c7;
  --color-info: #0284c7;           /* Sky Blue */
  --color-info-light: #e0f2fe;
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-size-xs: 0.75rem;         /* 12px */
  --font-size-sm: 0.875rem;        /* 14px */
  --font-size-base: 1rem;          /* 16px */
  --font-size-lg: 1.125rem;        /* 18px */
  --font-size-xl: 1.25rem;         /* 20px */
  --font-size-2xl: 1.5rem;         /* 24px */
  --font-size-3xl: 1.875rem;       /* 30px */
  --font-size-4xl: 2.25rem;        /* 36px */
  
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  
  /* Spacing (Compact 4px grid system) */
  --spacing-1: 0.25rem;   /* 4px */
  --spacing-2: 0.5rem;    /* 8px */
  --spacing-3: 0.75rem;   /* 12px */
  --spacing-4: 1rem;      /* 16px */
  --spacing-5: 1.25rem;   /* 20px */
  --spacing-6: 1.5rem;    /* 24px */
  --spacing-8: 1.5rem;    /* 24px - REDUCED from 32px */
  --spacing-10: 2rem;     /* 32px - REDUCED from 40px */
  --spacing-12: 2rem;     /* 32px - REDUCED from 48px */
  --spacing-16: 2.5rem;   /* 40px - REDUCED from 64px */
  
  /* Border Radius */
  --radius-sm: 0.25rem;   /* 4px */
  --radius-md: 0.5rem;    /* 8px */
  --radius-lg: 0.75rem;   /* 12px */
  --radius-xl: 1rem;      /* 16px */
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  --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);
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 200ms ease-in-out;
  --transition-slow: 300ms ease-in-out;
  
  /* Z-Index */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* ============================================================================
   GLOBAL RESETS & BASE STYLES
   ============================================================================ */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-gray-800);
  background-color: var(--color-gray-50);
}

/* ============================================================================
   TYPOGRAPHY
   ============================================================================ */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-semibold);
  line-height: var(--line-height-tight);
  color: var(--color-gray-900);
  margin-bottom: var(--spacing-2);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-base); }

p {
  margin-bottom: var(--spacing-2);
}

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

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

/* ============================================================================
   LAYOUT COMPONENTS
   ============================================================================ */

/* Container */
.container {
  width: 100%;
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--spacing-4);
}

.container-narrow {
  max-width: 1200px;
}

.container-wide {
  max-width: 1600px;
}

/* Card */
.card {
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: var(--spacing-4);
  margin-bottom: var(--spacing-4);
  border: 1px solid var(--color-gray-200);
  transition: box-shadow var(--transition-base);
}

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

.card-header {
  padding-bottom: var(--spacing-3);
  margin-bottom: var(--spacing-3);
  border-bottom: 1px solid var(--color-gray-200);
}

.card-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-gray-900);
  margin: 0;
}

.card-body {
  padding: var(--spacing-3) 0;
}

/* Grid */
.grid {
  display: grid;
  gap: var(--spacing-6);
}

.grid-cols-1 { grid-template-columns: repeat(1, minmax(0, 1fr)); }
.grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

/* Flexbox */
.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

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

.justify-between {
  justify-content: space-between;
}

.justify-center {
  justify-content: center;
}

.gap-2 { gap: var(--spacing-2); }
.gap-3 { gap: var(--spacing-3); }
.gap-4 { gap: var(--spacing-4); }
.gap-6 { gap: var(--spacing-6); }

/* ============================================================================
   BUTTONS
   ============================================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-2);
  padding: var(--spacing-3) var(--spacing-6);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  line-height: 1;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* Primary Button */
.btn-primary {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  color: white;
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover:not(:disabled) {
  background: var(--color-primary-dark);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

/* Secondary Button */
.btn-secondary {
  background: white;
  color: var(--color-gray-700);
  border-color: var(--color-gray-300);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--color-gray-50);
  border-color: var(--color-gray-400);
}

/* Danger Button */
.btn-danger {
  background: var(--color-danger);
  color: white;
}

.btn-danger:hover:not(:disabled) {
  background: #b91c1c;
  transform: translateY(-1px);
}

/* Success Button */
.btn-success {
  background: var(--color-success);
  color: white;
}

.btn-success:hover:not(:disabled) {
  background: #047857;
}

/* Ghost Button */
.btn-ghost {
  background: transparent;
  color: var(--color-gray-700);
}

.btn-ghost:hover:not(:disabled) {
  background: var(--color-gray-100);
}

/* Button Sizes */
.btn-sm {
  padding: var(--spacing-2) var(--spacing-4);
  font-size: var(--font-size-xs);
}

.btn-lg {
  padding: var(--spacing-4) var(--spacing-8);
  font-size: var(--font-size-base);
}

/* ============================================================================
   FORMS
   ============================================================================ */
.form-group {
  margin-bottom: var(--spacing-3);
}

.form-label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-gray-700);
  margin-bottom: var(--spacing-2);
}

.form-label-required::after {
  content: '*';
  color: var(--color-danger);
  margin-left: var(--spacing-1);
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: var(--spacing-3) var(--spacing-4);
  font-size: var(--font-size-sm);
  font-family: var(--font-family);
  color: var(--color-gray-800);
  background: white;
  border: 1px solid var(--color-gray-300);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.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-pale);
}

.form-input::placeholder {
  color: var(--color-gray-500);
}

.form-input:disabled,
.form-select:disabled,
.form-textarea:disabled {
  background: var(--color-gray-100);
  cursor: not-allowed;
}

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

.form-error {
  display: block;
  margin-top: var(--spacing-2);
  font-size: var(--font-size-sm);
  color: var(--color-danger);
}

.form-help {
  display: block;
  margin-top: var(--spacing-2);
  font-size: var(--font-size-sm);
  color: var(--color-gray-600);
}

/* Input with Icon */
.form-input-group {
  position: relative;
}

.form-input-icon {
  position: absolute;
  left: var(--spacing-3);
  top: 50%;
  transform: translateY(-50%);
  color: var(--color-gray-500);
  pointer-events: none;
}

.form-input-group .form-input {
  padding-left: var(--spacing-10);
}

/* ============================================================================
   TABLES
   ============================================================================ */
.table-wrapper {
  overflow-x: auto;
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-gray-200);
}

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

.table thead {
  background: var(--color-gray-50);
  border-bottom: 1px solid var(--color-gray-300);
}

.table th {
  padding: var(--spacing-2) var(--spacing-3);
  text-align: left;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-gray-700);
  white-space: nowrap;
}

.table th.text-right,
.table td.text-right {
  text-align: right;
}

.table tbody tr {
  border-bottom: 1px solid var(--color-gray-200);
  transition: background-color var(--transition-fast);
}

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

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

.table td {
  padding: var(--spacing-2) var(--spacing-3);
  font-size: var(--font-size-sm);
  color: var(--color-gray-800);
}

/* ============================================================================
   ALERTS & NOTIFICATIONS
   ============================================================================ */
.alert {
  padding: var(--spacing-3);
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  margin-bottom: var(--spacing-3);
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-2);
}

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

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

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

.alert-info {
  background: var(--color-info-light);
  border-color: var(--color-info);
  color: #075985;
}

/* ============================================================================
   BADGES
   ============================================================================ */
.badge {
  display: inline-flex;
  align-items: center;
  padding: var(--spacing-1) var(--spacing-3);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  border-radius: var(--radius-full);
}

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

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

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

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

/* ============================================================================
   LOADING STATES
   ============================================================================ */
.spinner {
  border: 3px solid var(--color-gray-200);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  animation: spin 0.8s linear infinite;
}

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

/* ============================================================================
   UTILITIES
   ============================================================================ */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-left { text-align: left; }

.text-xs { font-size: var(--font-size-xs); }
.text-sm { font-size: var(--font-size-sm); }
.text-base { font-size: var(--font-size-base); }
.text-lg { font-size: var(--font-size-lg); }
.text-xl { font-size: var(--font-size-xl); }
.text-2xl { font-size: var(--font-size-2xl); }

.font-medium { font-weight: var(--font-weight-medium); }
.font-semibold { font-weight: var(--font-weight-semibold); }
.font-bold { font-weight: var(--font-weight-bold); }

.text-gray-600 { color: var(--color-gray-600); }
.text-gray-700 { color: var(--color-gray-700); }
.text-gray-900 { color: var(--color-gray-900); }

.mb-2 { margin-bottom: var(--spacing-2); }
.mb-4 { margin-bottom: var(--spacing-4); }
.mb-6 { margin-bottom: var(--spacing-6); }
.mb-8 { margin-bottom: var(--spacing-8); }

.mt-2 { margin-top: var(--spacing-2); }
.mt-4 { margin-top: var(--spacing-4); }
.mt-6 { margin-top: var(--spacing-6); }
.mt-8 { margin-top: var(--spacing-8); }

/* ============================================================================
   RESPONSIVE DESIGN
   ============================================================================ */
@media (max-width: 768px) {
  .grid-cols-2,
  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: repeat(1, minmax(0, 1fr));
  }
  
  .container {
    padding: 0 var(--spacing-4);
  }
  
  .card {
    padding: var(--spacing-4);
  }
  
  h1 { font-size: var(--font-size-3xl); }
  h2 { font-size: var(--font-size-2xl); }
  h3 { font-size: var(--font-size-xl); }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}


/* ============================================================================
   v9 DESIGN UPGRADES — enhanced visual language applied globally
   ============================================================================ */

/* ── Page background ── */
body {
  background-color: #f0f4f8;
}

/* ── Card ── */
.card {
  border-radius: 16px;
  box-shadow: 0 2px 20px rgba(0,0,0,0.07);
  border: 1px solid rgba(0,0,0,0.06);
}
.card:hover {
  box-shadow: 0 4px 28px rgba(0,0,0,0.10);
}
.card-header {
  border-bottom: 1px solid rgba(0,0,0,0.07);
}
.card-title {
  font-size: 15px;
  font-weight: 700;
  color: #111827;
}

/* ── Table ── */
.table-wrapper {
  border-radius: 16px;
  border: none;
  box-shadow: 0 2px 20px rgba(0,0,0,0.07);
  overflow: hidden;
}
.table thead {
  background: #1e3a5f;
  border-bottom: none;
}
.table th {
  color: rgba(255,255,255,0.92);
  font-size: 0.78rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 13px 16px;
  font-weight: 600;
}
.table td {
  padding: 13px 16px;
}
.table tbody tr:nth-child(even) {
  background-color: #f8fafc;
}
.table tbody tr:hover {
  background-color: #eff6ff !important;
}

/* ── Buttons ── */
.btn {
  border-radius: 10px;
  font-weight: 600;
  letter-spacing: 0.01em;
}
.btn-primary {
  background: linear-gradient(135deg, #1e40af 0%, #3b82f6 100%);
  box-shadow: 0 2px 8px rgba(30,64,175,0.28);
  color: white;
}
.btn-primary:hover:not(:disabled) {
  background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 100%);
  box-shadow: 0 4px 16px rgba(30,64,175,0.38);
  transform: translateY(-1px);
  color: white;
}
.btn-success {
  background: linear-gradient(135deg, #059669 0%, #10b981 100%);
  box-shadow: 0 2px 8px rgba(5,150,105,0.28);
}
.btn-success:hover:not(:disabled) {
  background: linear-gradient(135deg, #047857 0%, #059669 100%);
  box-shadow: 0 4px 14px rgba(5,150,105,0.38);
  transform: translateY(-1px);
}
.btn-danger {
  background: linear-gradient(135deg, #dc2626 0%, #ef4444 100%);
  box-shadow: 0 2px 8px rgba(220,38,38,0.22);
}
.btn-danger:hover:not(:disabled) {
  background: linear-gradient(135deg, #b91c1c 0%, #dc2626 100%);
  box-shadow: 0 4px 14px rgba(220,38,38,0.32);
  transform: translateY(-1px);
}
.btn-secondary {
  background: white;
  border: 1.5px solid #d1d5db;
  color: #374151;
}
.btn-secondary:hover:not(:disabled) {
  background: #f9fafb;
  border-color: #9ca3af;
  color: #111827;
}

/* ── Inputs ── */
.form-input,
.form-select,
.form-textarea {
  border-radius: 10px;
  border: 1.5px solid #d1d5db;
}
.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: #3b82f6;
  box-shadow: 0 0 0 3px rgba(59,130,246,0.14);
}

/* ── Alerts ── */
.alert {
  border-radius: 12px;
}

/* ── Badges ── */
.badge {
  border-radius: 999px;
  font-weight: 600;
}

/* ── Page hero ── */
.page-hero {
  background: linear-gradient(135deg, #0f172a 0%, #1e40af 70%, #3b82f6 100%);
  color: white;
  padding: 42px 0 34px;
  margin-bottom: 32px;
}
.page-hero h1 {
  color: white;
  font-size: 28px;
  font-weight: 800;
  margin-bottom: 8px;
  letter-spacing: -0.3px;
}
.page-hero p {
  color: rgba(255,255,255,0.82);
  font-size: 15px;
  margin: 0;
}

/* ── Stat cards ── */
.stat-card {
  background: white;
  border-radius: 14px;
  padding: 20px 24px;
  box-shadow: 0 2px 20px rgba(0,0,0,0.07);
  border: 1px solid rgba(0,0,0,0.06);
  flex: 1;
}
.stat-value {
  font-size: 30px;
  font-weight: 700;
  color: #1e40af;
  line-height: 1.1;
}
.stat-label {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #9ca3af;
  margin-top: 4px;
}

/* ── Empty state ── */
.empty-state {
  text-align: center;
  padding: 64px 24px;
}

/* ── Navbar ── */
.navbar {
  background: #0f172a;
  box-shadow: 0 2px 16px rgba(0,0,0,0.25);
}

/* ── Filter pills ── */
.filter-pill {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 6px 14px;
  border-radius: 999px;
  border: 1.5px solid #d1d5db;
  background: #fff;
  font-size: 13px;
  font-weight: 500;
  color: #374151;
  cursor: pointer;
  transition: all 0.15s;
  user-select: none;
}
.filter-pill:hover {
  border-color: #3b82f6;
  color: #1d4ed8;
  background: #eff6ff;
}
.filter-pill.active {
  background: #1d4ed8;
  border-color: #1d4ed8;
  color: #fff;
}

/* ── Spin animation referenced in JS ── */
@keyframes spin { to { transform: rotate(360deg); } }

@media (max-width: 640px) {
  .page-hero { padding: 24px 0; }
  .page-hero h1 { font-size: 22px; }
}