:root {
  /* Light Theme Colors */
  --bg-color: #f3f4f6;
  --panel-bg: rgba(255, 255, 255, 0.7);
  --border-color: rgba(229, 231, 235, 0.8);
  --text-main: #111827;
  --text-muted: #6b7280;
  --primary-color: #4f46e5;
  --primary-hover: #4338ca;
  --danger-color: #ef4444;
  --glass-blur: blur(12px);
  --card-bg: #ffffff;
}

body.dark-theme {
  --bg-color: #0f172a;
  --panel-bg: rgba(30, 41, 59, 0.7);
  --border-color: rgba(51, 65, 85, 0.8);
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --primary-color: #818cf8;
  --primary-hover: #6366f1;
  --card-bg: #1e293b;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  transition: background-color 0.3s ease, color 0.3s ease;
  min-height: 100vh;
  margin: 0;
  overflow-x: hidden;
}

/* Base UI Styles */
.glass-panel {
  background: var(--panel-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
}

.app-container {
  display: flex;
  min-height: 100vh;
}

/* Sidebar */
.sidebar {
  width: 320px;
  min-width: 320px;
  padding: 1.5rem;
  border-right: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  background: var(--bg-color);
  z-index: 10;
}

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

.sidebar-header h1 {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.sidebar-header .accent {
  color: var(--primary-color);
}

.icon-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.5rem;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.icon-btn:hover {
  background: var(--border-color);
  color: var(--text-main);
}

/* Theme Icons Toggle */
body.light-theme .sun-icon { display: none; }
body.light-theme .moon-icon { display: block; }
body.dark-theme .sun-icon { display: block; }
body.dark-theme .moon-icon { display: none; }

/* Controls */
.controls-group {
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.controls-group label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
}

.controls-group input[type="text"],
.controls-group textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  background: var(--bg-color);
  color: var(--text-main);
  border-radius: 8px;
  font-family: inherit;
  font-size: 0.875rem;
  transition: border-color 0.2s;
  resize: vertical;
}

.controls-group input[type="text"]:focus,
.controls-group textarea:focus {
  outline: none;
  border-color: var(--primary-color);
}

.slider-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.slider-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
}

input[type="range"] {
  -webkit-appearance: none;
  width: 100%;
  height: 4px;
  background: var(--border-color);
  border-radius: 2px;
  outline: none;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--primary-color);
  cursor: pointer;
  border: 2px solid var(--bg-color);
}

/* Filters */
.filter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.chip {
  padding: 0.4rem 0.8rem;
  border-radius: 16px;
  border: 1px solid var(--border-color);
  background: transparent;
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  text-transform: capitalize;
}

.chip:hover {
  background: var(--border-color);
  color: var(--text-main);
}

.chip.active {
  background: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
}

.toggle-switch-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.label-text {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-main);
}

.switch {
  position: relative;
  display: inline-block;
  width: 44px;
  height: 24px;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider.round {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: var(--border-color);
  transition: .4s;
  border-radius: 24px;
}

.slider.round:before {
  position: absolute;
  content: "";
  height: 18px;
  width: 18px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .4s;
  border-radius: 50%;
}

input:checked + .slider.round {
  background-color: var(--primary-color);
}

input:checked + .slider.round:before {
  transform: translateX(20px);
}

/* Main Content */
.content-area {
  flex: 1;
  padding: 2rem;
  background: var(--bg-color);
}

.pairings-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
  gap: 2rem;
}

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 60vh;
  color: var(--text-muted);
  gap: 1rem;
}

.hidden {
  display: none !important;
}

/* Font Card */
.font-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  position: relative;
  transition: transform 0.2s, box-shadow 0.2s;
  animation: fadeIn 0.4s ease forwards;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.font-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  border-color: var(--primary-color);
}

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

.pair-info {
  display: flex;
  flex-direction: column;
}

.pair-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.pair-meta {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: capitalize;
}

.card-actions {
  display: flex;
  gap: 0.5rem;
}

.card-actions .icon-btn {
  padding: 0.4rem;
}

.card-actions .icon-btn svg {
  width: 18px;
  height: 18px;
}

.favorite-btn.active svg {
  fill: var(--danger-color);
  stroke: var(--danger-color);
}

.preview-area {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.preview-heading, .preview-body {
  word-break: break-word;
}

/* Modal */
.modal {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.modal-content {
  position: relative;
  width: 90%;
  max-width: 600px;
  padding: 2rem;
  z-index: 51;
  background: var(--card-bg);
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
}

.modal-header h2 {
  font-size: 1.25rem;
  font-weight: 600;
}

.code-block-wrapper {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.code-block-wrapper label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
}

.code-container {
  position: relative;
  background: #1e1e1e; /* Always dark for code */
  color: #d4d4d4;
  border-radius: 8px;
  padding: 1rem;
  overflow-x: auto;
}

.code-container pre {
  margin: 0;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.875rem;
  white-space: pre-wrap;
  word-break: break-all;
}

.code-container .copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

.code-container .copy-btn:hover {
  background: var(--primary-color);
}

.mt-4 { margin-top: 1rem; }

/* Toast */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  background: var(--text-main);
  color: var(--bg-color);
  padding: 0.75rem 1.5rem;
  border-radius: 20px;
  font-size: 0.875rem;
  font-weight: 500;
  z-index: 100;
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  animation: slideUp 0.3s ease;
}

@keyframes slideUp {
  from { opacity: 0; transform: translate(-50%, 20px); }
  to { opacity: 1; transform: translate(-50%, 0); }
}

@media (max-width: 768px) {
  .app-container {
    flex-direction: column;
  }
  .sidebar {
    width: 100%;
    height: auto;
    position: static;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  .pairings-grid {
    grid-template-columns: 1fr;
  }
}