:root {
  /* Design Tokens - Colors */
  --bg-main: #0b0f19;
  --bg-card: rgba(21, 29, 47, 0.65);
  --bg-card-hover: rgba(29, 39, 63, 0.85);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-focus: #f59e0b; /* Amber 500 */
  
  --primary: #f59e0b; /* Amber 500 */
  --primary-hover: #d97706; /* Amber 600 */
  --primary-glow: rgba(245, 158, 11, 0.15);
  
  --success: #10b981; /* Emerald 500 */
  --danger: #ef4444; /* Red 500 */
  --info: #3b82f6; /* Blue 500 */
  
  --text-primary: #f8fafc; /* Slate 50 */
  --text-secondary: #94a3b8; /* Slate 400 */
  --text-muted: #64748b; /* Slate 500 */
  
  /* Fonts */
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-display: 'Outfit', sans-serif;
  
  /* Radius & Shadows */
  --radius-lg: 16px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --shadow-lg: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px rgba(245, 158, 11, 0.2);
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html, body {
  width: 100%;
  height: 100%;
  background-color: var(--bg-main);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

body {
  background-image: 
    radial-gradient(at 0% 0%, rgba(245, 158, 11, 0.03) 0px, transparent 50%),
    radial-gradient(at 100% 100%, rgba(59, 130, 246, 0.02) 0px, transparent 50%),
    radial-gradient(at 50% 0%, rgba(16, 185, 129, 0.01) 0px, transparent 50%);
  background-attachment: fixed;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* Typography helper classes */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

p {
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Layout Utilities */
.app-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  max-width: 1600px;
  margin: 0 auto;
  padding: 1rem;
}

/* Header Styles */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 1rem 1.25rem 1rem;
  border-bottom: 1px solid var(--border-color);
}

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

.brand-icon {
  font-size: 2.25rem;
  filter: drop-shadow(0 0 10px rgba(245, 158, 11, 0.4));
  animation: pulse 3s infinite ease-in-out;
}

.brand h1 {
  font-size: 1.75rem;
  font-weight: 800;
  background: linear-gradient(135deg, #fff 0%, #f59e0b 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.brand span {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--text-muted);
  display: block;
  margin-top: -0.25rem;
}

/* Tabs & Navigation */
.app-nav {
  display: flex;
  gap: 0.5rem;
}

.nav-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-secondary);
  padding: 0.6rem 1.2rem;
  border-radius: var(--radius-md);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: all var(--transition-fast);
}

.nav-btn:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.04);
}

.nav-btn.active {
  color: var(--primary);
  background: rgba(245, 158, 11, 0.08);
  border-color: rgba(245, 158, 11, 0.2);
}

.nav-btn i {
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Main Layout Grid */
.main-layout {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 1.25rem;
  flex: 1;
  min-height: 0;
  margin-top: 1.25rem;
}

/* Glassmorphic Cards */
.glass-panel {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

/* Form Controls */
.input-group {
  margin-bottom: 1.25rem;
}

.input-label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.text-input {
  width: 100%;
  padding: 0.75rem 1rem;
  background: rgba(0, 0, 0, 0.25);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  transition: all var(--transition-fast);
}

.text-input:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 2px rgba(245, 158, 11, 0.15);
}

.select-input {
  width: 100%;
  padding: 0.75rem 1rem;
  background: rgba(0, 0, 0, 0.25) url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%2394a3b8' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3e%3c/svg%3e") no-repeat right 1rem center/1.25rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  appearance: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

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

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition-normal);
  border: 1px solid transparent;
  text-decoration: none;
}

.btn-primary {
  background: var(--primary);
  color: #000;
  font-weight: 700;
}

.btn-primary:hover {
  background: var(--primary-hover);
  box-shadow: var(--shadow-glow);
}

.btn-primary:disabled {
  background: var(--text-muted);
  color: rgba(0, 0, 0, 0.3);
  cursor: not-allowed;
  box-shadow: none;
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--border-color);
  color: var(--text-primary);
}

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

/* Keyframes animations */
@keyframes pulse {
  0%, 100% {
    transform: scale(1);
    opacity: 1;
    filter: drop-shadow(0 0 10px rgba(245, 158, 11, 0.4));
  }
  50% {
    transform: scale(1.05);
    opacity: 0.9;
    filter: drop-shadow(0 0 18px rgba(245, 158, 11, 0.7));
  }
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.fade-in {
  animation: fadeIn 0.3s ease-out forwards;
}

/* Typing Indicator Animation */
.typing-indicator {
  display: flex;
  align-items: center;
  gap: 4px;
  height: 20px;
  padding: 0 0.5rem;
}

.typing-indicator span {
  display: inline-block;
  width: 6px;
  height: 6px;
  background-color: var(--primary);
  border-radius: 50%;
  animation: typing 1s infinite ease-in-out;
}
.typing-indicator span:nth-child(2) {
  animation-delay: 0.2s;
}
.typing-indicator span:nth-child(3) {
  animation-delay: 0.4s;
}
@keyframes typing {
  0%, 100% { transform: translateY(0); opacity: 0.4; }
  50% { transform: translateY(-4px); opacity: 1; }
}

/* Responsive */
@media (max-width: 960px) {
  .main-layout {
    grid-template-columns: 1fr;
    overflow-y: auto;
  }
  
  .app-container {
    height: auto;
  }
}

/* TTS Voice Button Style */
.tts-play-btn {
  position: absolute;
  right: 0.6rem;
  bottom: 0.6rem;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: rgba(245, 158, 11, 0.08);
  border: 1px solid rgba(245, 158, 11, 0.25);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.tts-play-btn:hover {
  background: rgba(245, 158, 11, 0.15);
  border-color: rgba(245, 158, 11, 0.5);
}

.tts-play-btn i {
  width: 18px;
  height: 18px;
  color: var(--primary);
  transition: color var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Active speaking state: Green with pulse animation */
.tts-play-btn.speaking {
  background: rgba(16, 185, 129, 0.15) !important;
  border: 1px solid rgba(16, 185, 129, 0.5) !important;
  animation: tts-pulse 2s infinite ease-in-out;
}

.tts-play-btn.speaking:hover {
  background: rgba(16, 185, 129, 0.25) !important;
  border-color: rgba(16, 185, 129, 0.7) !important;
}

.tts-play-btn.speaking i {
  color: var(--success) !important;
}

@keyframes tts-pulse {
  0%, 100% {
    box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.4), 0 2px 8px rgba(0, 0, 0, 0.3);
    border-color: rgba(16, 185, 129, 0.5);
  }
  50% {
    box-shadow: 0 0 0 8px rgba(16, 185, 129, 0), 0 2px 8px rgba(0, 0, 0, 0.3);
    border-color: rgba(16, 185, 129, 0.8);
  }
}