/* CSS Variables for Theming */
:root {
  --bg-primary: #f5f7fa;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --text-primary: #1a1a1a;
  --text-secondary: #666666;
  --text-muted: #999999;
  --border-color: #e0e0e0;
  --accent-color: #3b82f6;
  --accent-hover: #2563eb;
  --success-color: #10b981;
  --danger-color: #ef4444;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
  --transition: all 0.3s ease;
}

[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-card: #1e293b;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --border-color: #334155;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.4);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: var(--transition);
}

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.header {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--accent-color);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo-icon {
  font-size: 2rem;
}

.header-actions {
  display: flex;
  gap: 1rem;
  align-items: center;
}

/* Buttons */
.btn {
  padding: 0.625rem 1.25rem;
  border: none;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  background-color: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

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

.btn-primary {
  background-color: var(--accent-color);
  color: white;
  border: none;
}

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

.btn-refresh {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.refresh-icon {
  font-size: 1.25rem;
  display: inline-block;
  transition: transform 0.3s ease;
}

.btn-refresh:hover .refresh-icon {
  transform: rotate(180deg);
}

.btn-theme {
  padding: 0.625rem;
  font-size: 1.25rem;
}

/* Controls Section */
.controls {
  margin: 2rem 0;
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  justify-content: space-between;
  align-items: flex-start;
}

.search-filter {
  flex: 1;
  min-width: 300px;
}

.search-input {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 1rem;
  background-color: var(--bg-card);
  color: var(--text-primary);
  margin-bottom: 1rem;
  transition: var(--transition);
}

.search-input:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.filter-buttons {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.btn-filter {
  padding: 0.5rem 1rem;
  font-size: 0.9rem;
}

.btn-filter.active {
  background-color: var(--accent-color);
  color: white;
  border-color: var(--accent-color);
}

.heart-icon {
  color: var(--danger-color);
}

.sort-section {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.sort-select {
  padding: 0.625rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 0.95rem;
  background-color: var(--bg-card);
  color: var(--text-primary);
  cursor: pointer;
  transition: var(--transition);
}

.sort-select:focus {
  outline: none;
  border-color: var(--accent-color);
}

/* Loading & Error States */
.loading {
  text-align: center;
  padding: 4rem 2rem;
}

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

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

.error {
  text-align: center;
  padding: 4rem 2rem;
}

.error-message {
  color: var(--danger-color);
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

/* Coins Grid */
.coins-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.coin-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.25rem;
  transition: var(--transition);
  cursor: pointer;
  position: relative;
}

.coin-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.coin-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1rem;
}

.coin-info {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.coin-image {
  width: 40px;
  height: 40px;
  border-radius: 50%;
}

.coin-name-symbol h3 {
  font-size: 1.1rem;
  margin-bottom: 0.25rem;
}

.coin-symbol {
  color: var(--text-muted);
  text-transform: uppercase;
  font-size: 0.85rem;
}

.favorite-btn {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-muted);
  transition: var(--transition);
  padding: 0.25rem;
}

.favorite-btn:hover,
.favorite-btn.active {
  color: var(--danger-color);
  transform: scale(1.2);
}

.coin-price {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.coin-change {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.coin-change.positive {
  background-color: rgba(16, 185, 129, 0.1);
  color: var(--success-color);
}

.coin-change.negative {
  background-color: rgba(239, 68, 68, 0.1);
  color: var(--danger-color);
}

.coin-stats {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-color);
}

.coin-stat {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
}

.coin-stat-label {
  color: var(--text-secondary);
}

.coin-stat-value {
  font-weight: 600;
}

.coin-sparkline {
  width: 100%;
  height: 60px;
  margin-top: 1rem;
}

.coin-sparkline canvas {
  width: 100% !important;
  height: 100% !important;
}

/* Pagination */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  margin: 3rem 0;
  flex-wrap: wrap;
}

.btn-page {
  padding: 0.625rem 1.25rem;
}

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

.page-numbers {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.page-number {
  padding: 0.5rem 0.875rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background-color: var(--bg-card);
  color: var(--text-primary);
  cursor: pointer;
  transition: var(--transition);
  font-weight: 500;
}

.page-number:hover {
  background-color: var(--accent-color);
  color: white;
  border-color: var(--accent-color);
}

.page-number.active {
  background-color: var(--accent-color);
  color: white;
  border-color: var(--accent-color);
}

/* Modal */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.modal.active {
  display: flex;
}

.modal-content {
  background-color: var(--bg-card);
  border-radius: 12px;
  max-width: 500px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
  font-size: 1.5rem;
}

.modal-close {
  background: none;
  border: none;
  font-size: 2rem;
  cursor: pointer;
  color: var(--text-secondary);
  transition: var(--transition);
  padding: 0;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.modal-body {
  padding: 1.5rem;
}

.calculator-coin-info {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.calc-coin-image {
  width: 50px;
  height: 50px;
  border-radius: 50%;
}

.calculator-coin-info h3 {
  font-size: 1.25rem;
  margin-bottom: 0.25rem;
}

.calculator-coin-info p {
  color: var(--text-muted);
  text-transform: uppercase;
}

.calculator-input {
  margin-bottom: 1.5rem;
}

.calculator-input label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
}

.calculator-input input {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 1rem;
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

.calculator-input input:focus {
  outline: none;
  border-color: var(--accent-color);
}

.calculator-results h3 {
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

.currency-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.currency-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem;
  background-color: var(--bg-primary);
  border-radius: 8px;
}

.currency-label {
  font-weight: 500;
  color: var(--text-secondary);
}

.currency-value {
  font-weight: 700;
  font-size: 1.1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    gap: 1rem;
  }

  .controls {
    flex-direction: column;
  }

  .search-filter {
    width: 100%;
  }

  .sort-section {
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
  }

  .sort-select {
    width: 100%;
  }

  .coins-grid {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
  }

  .pagination {
    flex-direction: column;
  }

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

@media (max-width: 480px) {
  .coins-grid {
    grid-template-columns: 1fr;
  }

  .filter-buttons {
    flex-direction: column;
  }

  .btn-filter {
    width: 100%;
  }
}