/* CSS Reset and Base Styles */
:root {
  /* Color Palette */
  --primary-color: #2c5530;
  --primary-light: #4a7c59;
  --primary-dark: #1e3a21;
  --secondary-color: #e8f5e8;
  --accent-color: #ff6b35;
  --success-color: #28a745;
  --danger-color: #dc3545;
  --warning-color: #ffc107;
  
  /* Neutral Colors */
  --background-color: #f8faf9;
  --surface-color: #ffffff;
  --card-background: #ffffff;
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --text-muted: #8e9aaf;
  --border-color: #e9ecef;
  --border-light: #f1f3f4;
  
  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 25px rgba(0, 0, 0, 0.15);
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  
  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  
  /* Breakpoints (for reference) */
  --breakpoint-sm: 576px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 992px;
  --breakpoint-xl: 1200px;
  
  /* Animation */
  --transition-fast: 0.15s ease-in-out;
  --transition-normal: 0.3s ease-in-out;
  --transition-slow: 0.5s ease-in-out;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
}

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--background-color);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Layout Components */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-4);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header Styles */
.header {
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
  color: white;
  padding: var(--space-8) 0;
  position: relative;
  overflow: hidden;
}

.header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" patternUnits="userSpaceOnUse" width="100" height="100"><circle cx="50" cy="50" r="1" fill="%23ffffff" opacity="0.05"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>') repeat;
  opacity: 0.3;
}

.header-content {
  text-align: center;
  position: relative;
  z-index: 1;
}

.header-title {
  font-size: var(--font-size-3xl);
  font-weight: 600;
  margin-bottom: var(--space-2);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
}

.currency-symbol {
  font-size: 2.5rem;
  background: linear-gradient(45deg, #ffd700, #ffed4e);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.3));
}

.header-subtitle {
  font-size: var(--font-size-lg);
  opacity: 0.9;
  margin-bottom: var(--space-4);
  font-weight: 300;
}

.date-display {
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-lg);
  padding: var(--space-2) var(--space-4);
  display: inline-block;
  font-weight: 500;
  font-size: var(--font-size-sm);
}

/* Main Content */
.main-content {
  flex: 1;
  padding: var(--space-8) 0;
}

/* Controls */
.controls {
  display: flex;
  gap: var(--space-4);
  margin-bottom: var(--space-8);
  align-items: center;
  flex-wrap: wrap;
}

.search-container {
  position: relative;
  flex: 1;
  min-width: 240px;
}

.search-container input {
  width: 100%;
  padding: var(--space-3) var(--space-4) var(--space-3) var(--space-12);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-lg);
  font-size: var(--font-size-base);
  background: var(--surface-color);
  transition: all var(--transition-normal);
  outline: none;
}

.search-container input:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(44, 85, 48, 0.1);
}

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

.search-icon {
  position: absolute;
  left: var(--space-4);
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
}

.refresh-btn {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  background: var(--primary-color);
  color: white;
  border: none;
  border-radius: var(--radius-lg);
  font-size: var(--font-size-sm);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-normal);
  white-space: nowrap;
}

.refresh-btn:hover {
  background: var(--primary-light);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.refresh-btn:active {
  transform: translateY(0);
}

.refresh-btn.loading {
  pointer-events: none;
  opacity: 0.7;
}

.refresh-btn.loading svg {
  animation: spin 1s linear infinite;
}

/* Loading State */
.loading-state {
  text-align: center;
  padding: var(--space-12) var(--space-4);
  background: var(--surface-color);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
}

.spinner {
  width: 40px;
  height: 40px;
  margin: 0 auto var(--space-4);
  border: 4px solid var(--border-light);
  border-top: 4px solid var(--primary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

/* Error State */
.error-state {
  text-align: center;
  padding: var(--space-12) var(--space-4);
  background: var(--surface-color);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
  border-left: 4px solid var(--danger-color);
}

.error-icon {
  font-size: 3rem;
  margin-bottom: var(--space-4);
}

.error-state h3 {
  color: var(--danger-color);
  margin-bottom: var(--space-2);
  font-size: var(--font-size-xl);
}

.error-state p {
  color: var(--text-secondary);
  margin-bottom: var(--space-6);
}

.retry-btn {
  padding: var(--space-3) var(--space-6);
  background: var(--danger-color);
  color: white;
  border: none;
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.retry-btn:hover {
  background: #c82333;
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

/* Table Container */
.table-container {
  background: var(--surface-color);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-light);
}

/* Table Styles */
.currency-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
}

.currency-table thead {
  background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
  color: white;
}

.currency-table th {
  padding: var(--space-4);
  text-align: left;
  font-weight: 600;
  font-size: var(--font-size-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  position: relative;
}

.currency-table th.sortable {
  cursor: pointer;
  user-select: none;
  transition: background-color var(--transition-fast);
}

.currency-table th.sortable:hover {
  background: rgba(255, 255, 255, 0.1);
}

.sort-icon {
  margin-left: var(--space-2);
  opacity: 0.6;
  transition: opacity var(--transition-fast);
}

.currency-table th[aria-sort="ascending"] .sort-icon::before {
  content: '↑';
}

.currency-table th[aria-sort="descending"] .sort-icon::before {
  content: '↓';
}

.currency-table th.sortable:hover .sort-icon {
  opacity: 1;
}

.currency-table td {
  padding: var(--space-4);
  border-bottom: 1px solid var(--border-light);
  vertical-align: middle;
}

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

.currency-table tbody tr:hover {
  background: var(--secondary-color);
  transform: scale(1.01);
  box-shadow: 0 2px 8px rgba(44, 85, 48, 0.1);
}

.currency-table tbody tr:nth-child(even) {
  background: #fafbfc;
}

.currency-table tbody tr:nth-child(even):hover {
  background: var(--secondary-color);
}

/* Currency code styling */
.currency-table td:first-child {
  font-weight: 600;
  color: var(--primary-color);
  font-family: 'Monaco', 'Consolas', monospace;
}

/* Rate styling */
.currency-table td:nth-child(4) {
  font-weight: 500;
  font-family: 'Monaco', 'Consolas', monospace;
}

/* Change styling */
.currency-table .change-positive {
  color: var(--success-color);
  font-weight: 500;
}

.currency-table .change-negative {
  color: var(--danger-color);
  font-weight: 500;
}

.currency-table .change-neutral {
  color: var(--text-muted);
}

/* No Results */
.no-results {
  text-align: center;
  padding: var(--space-12) var(--space-4);
  background: var(--surface-color);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
  color: var(--text-secondary);
}

/* Footer */
.footer {
  margin-top: auto;
  padding: var(--space-6) 0;
  text-align: center;
  color: var(--text-secondary);
  font-size: var(--font-size-sm);
  border-top: 1px solid var(--border-light);
}

.footer a {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
}

.footer a:hover {
  text-decoration: underline;
}

.last-updated {
  margin-top: var(--space-2);
  font-size: var(--font-size-xs);
  opacity: 0.8;
}

/* Animations */
@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.currency-table tbody tr {
  animation: fadeIn 0.3s ease-out;
}

/* Responsive Design */

/* Tablet styles */
@media (max-width: 992px) {
  .container {
    padding: 0 var(--space-3);
  }
  
  .header {
    padding: var(--space-6) 0;
  }
  
  .header-title {
    font-size: var(--font-size-2xl);
  }
  
  .main-content {
    padding: var(--space-6) 0;
  }
  
  .controls {
    gap: var(--space-3);
    margin-bottom: var(--space-6);
  }
  
  .currency-table th,
  .currency-table td {
    padding: var(--space-3);
  }
}

/* Mobile styles */
@media (max-width: 768px) {
  .container {
    padding: 0 var(--space-2);
  }
  
  .header {
    padding: var(--space-4) 0;
  }
  
  .header-title {
    font-size: var(--font-size-xl);
    flex-direction: column;
    gap: var(--space-2);
  }
  
  .currency-symbol {
    font-size: 2rem;
  }
  
  .controls {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-3);
  }
  
  .search-container {
    min-width: unset;
  }
  
  .refresh-btn {
    justify-content: center;
  }
  
  /* Hide less important columns on mobile */
  .currency-table th.currency-name,
  .currency-table td:nth-child(2) {
    display: none;
  }
  
  .currency-table th,
  .currency-table td {
    padding: var(--space-2) var(--space-1);
    font-size: var(--font-size-xs);
  }
  
  .currency-table td:first-child {
    font-size: var(--font-size-sm);
  }
  
  /* Stack table content vertically for very small screens */
  @media (max-width: 480px) {
    .table-container {
      overflow-x: auto;
    }
    
    .currency-table {
      min-width: 320px;
    }
  }
}

/* Large screen optimizations */
@media (min-width: 1200px) {
  .header-title {
    font-size: 3.5rem;
  }
  
  .currency-symbol {
    font-size: 3rem;
  }
  
  .currency-table {
    font-size: var(--font-size-base);
  }
  
  .currency-table th,
  .currency-table td {
    padding: var(--space-5);
  }
}

/* Dark mode support (for future enhancement) */
@media (prefers-color-scheme: dark) {
  :root {
    --background-color: #0d1117;
    --surface-color: #161b22;
    --card-background: #21262d;
    --text-primary: #f0f6fc;
    --text-secondary: #8b949e;
    --text-muted: #6e7681;
    --border-color: #30363d;
    --border-light: #21262d;
  }
  
  .currency-table tbody tr:nth-child(even) {
    background: #161b22;
  }
  
  .currency-table tbody tr:hover {
    background: #21262d;
  }
}

/* Print styles */
@media print {
  .controls,
  .loading-state,
  .error-state,
  .footer {
    display: none;
  }
  
  .header {
    background: none !important;
    color: black !important;
    box-shadow: none;
  }
  
  .currency-table {
    box-shadow: none;
    border: 1px solid #000;
  }
  
  .currency-table th {
    background: #f0f0f0 !important;
    color: black !important;
  }
}