:root {
  --bg-color: #0f172a;
  --panel-bg: rgba(30, 41, 59, 0.6);
  --panel-border: rgba(255, 255, 255, 0.08);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --accent-cyan: #06b6d4;
  --accent-cyan-glow: rgba(6, 182, 212, 0.4);
  --accent-pink: #ec4899;
  --accent-pink-glow: rgba(236, 72, 153, 0.4);
  --accent-green: #10b981;
  --danger: #ef4444;
  
  --match-bg-1: rgba(6, 182, 212, 0.25);
  --match-border-1: rgba(6, 182, 212, 0.8);
  --match-bg-2: rgba(236, 72, 153, 0.25);
  --match-border-2: rgba(236, 72, 153, 0.8);
  
  --radius-md: 12px;
  --radius-sm: 8px;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'Fira Code', ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  background-image: 
    radial-gradient(circle at 15% 50%, rgba(6, 182, 212, 0.05), transparent 25%),
    radial-gradient(circle at 85% 30%, rgba(236, 72, 153, 0.05), transparent 25%);
  background-attachment: fixed;
}

.font-mono {
  font-family: var(--font-mono);
}

.app-layout {
  display: flex;
  flex-direction: column;
  height: 100vh;
  max-width: 1400px;
  margin: 0 auto;
}

/* Header */
.top-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--panel-border);
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(12px);
  z-index: 10;
}

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

.neon-cyan {
  color: var(--accent-cyan);
  filter: drop-shadow(0 0 4px var(--accent-cyan-glow));
}

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

h1 span {
  color: var(--text-secondary);
  font-weight: 500;
}

.btn {
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-weight: 500;
  font-size: 0.875rem;
  cursor: pointer;
  transition: all 0.2s ease;
  border: none;
  font-family: inherit;
}

.btn.secondary {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  color: var(--text-primary);
}

.btn.secondary:hover {
  background: rgba(255,255,255,0.1);
}

.icon-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 0.25rem;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

.icon-btn:hover {
  color: var(--text-primary);
  background: rgba(255,255,255,0.1);
}

/* Main Content Layout */
.main-content {
  display: flex;
  flex: 1;
  overflow: hidden;
  padding: 1.5rem;
  gap: 1.5rem;
}

.editor-pane {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  overflow-y: auto;
  padding-right: 0.5rem;
}

/* Glass Panels */
.glass-panel {
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
}

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

.panel-header h2 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.badge {
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-green);
  padding: 0.25rem 0.5rem;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 600;
  border: 1px solid rgba(16, 185, 129, 0.3);
}

/* Regex Input */
.flags-group {
  display: flex;
  gap: 1rem;
}

.flag-label {
  font-size: 0.8rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.25rem;
  cursor: pointer;
}

.regex-input-wrapper {
  display: flex;
  align-items: center;
  background: rgba(0, 0, 0, 0.4);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.regex-input-wrapper:focus-within {
  border-color: var(--accent-cyan);
  box-shadow: 0 0 0 2px var(--accent-cyan-glow);
}

.regex-slash, .regex-flags-display {
  color: var(--accent-pink);
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 600;
  user-select: none;
}

.regex-input {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-size: 1.1rem;
  padding: 0 0.5rem;
  outline: none;
}

.error-msg {
  color: var(--danger);
  font-size: 0.8rem;
  margin-top: 0.5rem;
}

.hidden {
  display: none !important;
}

/* Syntax Breakdown */
.breakdown-container {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
}

.token {
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid var(--panel-border);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  display: inline-flex;
  flex-direction: column;
  transition: background 0.2s ease;
}

.token:hover {
  background: rgba(255,255,255,0.05);
  border-color: rgba(255,255,255,0.2);
}

.token-val {
  color: var(--accent-cyan);
  font-weight: 600;
}

.token-desc {
  font-family: var(--font-sans);
  font-size: 0.7rem;
  color: var(--text-secondary);
  white-space: nowrap;
}

/* Test String Editor */
.editor-container {
  position: relative;
  min-height: 200px;
  background: rgba(0, 0, 0, 0.4);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.backdrop, #test-string {
  width: 100%;
  height: 100%;
  padding: 1rem;
  font-size: 1rem;
  line-height: 1.6;
  white-space: pre-wrap;
  word-wrap: break-word;
}

.backdrop {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 1;
  pointer-events: none;
  color: transparent; /* Text is transparent, only highlights show */
}

#test-string {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 2;
  color: var(--text-primary);
  background: transparent;
  border: none;
  outline: none;
  resize: vertical;
}

/* Highlights */
mark {
  border-radius: 3px;
  padding: 0.1rem 0;
  color: transparent;
}

.match-0 {
  background-color: var(--match-bg-1);
  border-bottom: 2px solid var(--match-border-1);
}

.match-1 {
  background-color: var(--match-bg-2);
  border-bottom: 2px solid var(--match-border-2);
}

/* Export Cards */
.export-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.export-card {
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.export-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 0.75rem;
  background: rgba(255,255,255,0.02);
  border-bottom: 1px solid var(--panel-border);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.export-card pre {
  padding: 0.75rem;
  margin: 0;
  overflow-x: auto;
  font-size: 0.85rem;
  color: var(--text-primary);
}

/* Cheat Sheet Sidebar */
.cheatsheet-sidebar {
  width: 320px;
  flex-shrink: 0;
  height: 100%;
  overflow-y: auto;
  transition: transform 0.3s ease, width 0.3s ease, margin 0.3s ease, opacity 0.3s ease;
}

.cheatsheet-sidebar:not(.open) {
  width: 0;
  margin-left: -1.5rem;
  opacity: 0;
  pointer-events: none;
}

.cheatsheet-content {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.cheat-group h3 {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-cyan);
  margin-bottom: 0.75rem;
}

.cheat-group ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.cheat-group li {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.85rem;
  border-bottom: 1px solid rgba(255,255,255,0.05);
  padding-bottom: 0.5rem;
}

.cheat-group code {
  color: var(--accent-pink);
  font-family: var(--font-mono);
  background: rgba(0,0,0,0.3);
  padding: 0.1rem 0.3rem;
  border-radius: 4px;
}

.cheat-group span {
  color: var(--text-secondary);
  text-align: right;
  flex: 1;
  margin-left: 1rem;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  background: var(--text-primary);
  color: var(--bg-color);
  padding: 0.75rem 1.5rem;
  border-radius: 20px;
  font-weight: 600;
  font-size: 0.9rem;
  box-shadow: 0 10px 25px rgba(0,0,0,0.5);
  z-index: 100;
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.toast.hidden {
  opacity: 0;
  transform: translate(-50%, 20px);
  pointer-events: none;
}

/* Responsive */
@media (max-width: 900px) {
  .main-content {
    flex-direction: column;
  }
  .cheatsheet-sidebar {
    position: fixed;
    top: 60px;
    right: 0;
    bottom: 0;
    z-index: 50;
    border-radius: 0;
    border-right: none;
    border-bottom: none;
    border-top: none;
    transform: translateX(100%);
  }
  .cheatsheet-sidebar.open {
    transform: translateX(0);
    width: 320px;
    margin-left: 0;
  }
  .editor-pane {
    padding-right: 0;
  }
}