/* ===== CSS VARIABLES & ROOT ===== */
:root {
  /* Light Theme Colors */
  --primary-color: #007AFF;
  --primary-hover: #0056CC;
  --secondary-color: #5856D6;
  --accent-color: #FF9500;
  --success-color: #34C759;
  --warning-color: #FF9500;
  --error-color: #FF3B30;
  
  --background-primary: #FFFFFF;
  --background-secondary: #F2F2F7;
  --background-tertiary: #FFFFFF;
  --surface-primary: #FFFFFF;
  --surface-secondary: #F9F9F9;
  
  --text-primary: #000000;
  --text-secondary: #3C3C43;
  --text-tertiary: #8E8E93;
  --text-inverse: #FFFFFF;
  
  --border-primary: #E5E5EA;
  --border-secondary: #D1D1D6;
  --shadow-light: rgba(0, 0, 0, 0.04);
  --shadow-medium: rgba(0, 0, 0, 0.08);
  --shadow-heavy: rgba(0, 0, 0, 0.16);
  
  /* Spacing System (8px base) */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  
  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  
  /* Typography */
  --font-size-xs: 12px;
  --font-size-sm: 14px;
  --font-size-base: 16px;
  --font-size-lg: 18px;
  --font-size-xl: 20px;
  --font-size-2xl: 24px;
  --font-size-3xl: 32px;
  
  --line-height-tight: 1.2;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.6;
  
  /* Transitions */
  --transition-fast: 0.15s ease-out;
  --transition-normal: 0.25s ease-out;
  --transition-slow: 0.35s ease-out;
  
  /* Layout */
  --sidebar-width: 280px;
  --header-height: 64px;
}

/* Dark Theme */
[data-theme="dark"] {
  --primary-color: #0A84FF;
  --primary-hover: #409CFF;
  --secondary-color: #5E5CE6;
  --accent-color: #FF9F0A;
  --success-color: #30D158;
  --warning-color: #FF9F0A;
  --error-color: #FF453A;
  
  --background-primary: #000000;
  --background-secondary: #1C1C1E;
  --background-tertiary: #2C2C2E;
  --surface-primary: #1C1C1E;
  --surface-secondary: #2C2C2E;
  
  --text-primary: #FFFFFF;
  --text-secondary: #EBEBF5;
  --text-tertiary: #8E8E93;
  --text-inverse: #000000;
  
  --border-primary: #38383A;
  --border-secondary: #48484A;
  --shadow-light: rgba(0, 0, 0, 0.2);
  --shadow-medium: rgba(0, 0, 0, 0.3);
  --shadow-heavy: rgba(0, 0, 0, 0.5);
}

/* ===== RESET & GLOBAL STYLES ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--background-primary);
  color: var(--text-primary);
  line-height: var(--line-height-normal);
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

/* ===== SIDEBAR ===== */
.sidebar {
  position: fixed;
  top: 0;
  left: calc(-1 * var(--sidebar-width));
  width: var(--sidebar-width);
  height: 100vh;
  background-color: var(--surface-primary);
  border-right: 1px solid var(--border-primary);
  z-index: 1000;
  transition: left var(--transition-normal);
  display: flex;
  flex-direction: column;
  box-shadow: 2px 0 12px var(--shadow-light);
}

.sidebar.open {
  left: 0;
}

.sidebar-toggle {
  position: absolute;
  top: var(--space-md);
  right: -48px;
  width: 40px;
  height: 40px;
  background-color: var(--surface-primary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  box-shadow: 0 2px 8px var(--shadow-light);
}

.sidebar-toggle:hover {
  background-color: var(--surface-secondary);
  transform: translateX(-2px);
  box-shadow: 0 4px 12px var(--shadow-medium);
}

.sidebar-toggle .material-icons {
  color: var(--text-primary);
  font-size: 20px;
}

.sidebar h2 {
  padding: var(--space-xl) var(--space-lg) var(--space-md);
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--text-primary);
  border-bottom: 1px solid var(--border-primary);
}

.history-list {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-md);
}

.history-item {
  width: 100%;
  padding: var(--space-md);
  margin-bottom: var(--space-sm);
  background-color: transparent;
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: left;
  font-size: var(--font-size-sm);
}

.history-item:hover {
  background-color: var(--surface-secondary);
  border-color: var(--primary-color);
  color: var(--text-primary);
  transform: translateY(-1px);
}

.newChat {
  width: 90%;
  margin: 10px auto;
  padding: 10px 15px;
  background-color: #4CAF50; 
  color: white;             
  border: none;              
  border-radius: 5px;       
  cursor: pointer;           
  font-size: 16px;           
  display: block;           
  transition: background-color 0.3s ease; 
}

.newChat:hover {
  background-color: #37923b; 
}


/* ===== HEADER ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background-color: var(--surface-primary);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-lg);
  z-index: 900;
  transition: all var(--transition-normal);
}

.logo {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-left: 40px;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.header-controls {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.header-controls button {
  width: 40px;
  height: 40px;
  background-color: transparent;
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.header-controls button:hover {
  background-color: var(--surface-secondary);
  border-color: var(--primary-color);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px var(--shadow-light);
}

.header-controls button .material-icons {
  color: var(--text-secondary);
  font-size: 20px;
  transition: color var(--transition-fast);
}

.header-controls button:hover .material-icons {
  color: var(--primary-color);
}

/* ===== MAIN CONTAINER ===== */
.container {
  margin-top: var(--header-height);
  padding: var(--space-lg);
  min-height: calc(100vh - var(--header-height));
  display: flex;
  flex-direction: column;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
}

/* ===== CHATBOX ===== */
.chatbox {
  flex: 1;
  background-color: var(--surface-primary);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  margin-bottom: var(--space-lg);
  min-height: 400px;
  max-height: 600px;
  overflow-y: auto;
  border: 1px solid var(--border-primary);
  box-shadow: 0 4px 20px var(--shadow-light);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  scroll-behavior: smooth;
}

.chatbox::-webkit-scrollbar {
  width: 6px;
}

.chatbox::-webkit-scrollbar-track {
  background: var(--surface-secondary);
  border-radius: 3px;
}

.chatbox::-webkit-scrollbar-thumb {
  background: var(--border-secondary);
  border-radius: 3px;
}

.chatbox::-webkit-scrollbar-thumb:hover {
  background: var(--text-tertiary);
}

/* ===== WELCOME MESSAGE ===== */
.welcome-message {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-2xl);
  color: var(--text-secondary);
  height: 100%;
  min-height: 300px;
}

.welcome-icon {
  font-size: 4rem;
  margin-bottom: var(--space-lg);
  opacity: 0.8;
}

.welcome-message h3 {
  font-size: var(--font-size-2xl);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-md);
}

.welcome-message p {
  font-size: var(--font-size-base);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-sm);
  max-width: 400px;
}

/* ===== CHAT MESSAGES ===== */
.chat-message {
  max-width: 80%;
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-lg);
  position: relative;
  word-wrap: break-word;
  line-height: var(--line-height-relaxed);
  animation: slideIn 0.3s ease-out;
  box-shadow: 0 2px 8px var(--shadow-light);
}

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

.user-message {
  background-color: var(--primary-color);
  color: var(--text-inverse);
  align-self: flex-end;
  margin-left: auto;
  border-bottom-right-radius: var(--radius-sm);
}

.assistant-message {
  background-color: var(--surface-secondary);
  color: var(--text-primary);
  align-self: flex-start;
  border-bottom-left-radius: var(--radius-sm);
  border: 1px solid var(--border-primary);
}

.timestamp {
  font-size: var(--font-size-xs);
  margin-top: var(--space-xs);
  opacity: 0.7;
}

/* ===== INPUT AREA ===== */
.input-area {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  background-color: var(--surface-primary);
  padding: var(--space-lg);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-primary);
  box-shadow: 0 4px 20px var(--shadow-light);
  position: relative;
}

#chatInput {
  flex: 1;
  padding: var(--space-md) var(--space-lg);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  background-color: var(--surface-secondary);
  color: var(--text-primary);
  font-size: var(--font-size-base);
  transition: all var(--transition-fast);
  outline: none;
}

#chatInput:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
}

#chatInput::placeholder {
  color: var(--text-tertiary);
}

#voiceButton,
#sendButton,
#stopSpeechButton {
  width: 48px;
  height: 48px;
  background-color: var(--primary-color);
  border: none;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  box-shadow: 0 2px 8px var(--shadow-light);
}

#voiceButton:hover,
#sendButton:hover,
#stopSpeechButton:hover {
  background-color: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px var(--shadow-medium);
}

#voiceButton .material-icons,
#sendButton .material-icons,
#stopSpeechButton .material-icons {
  color: var(--text-inverse);
  font-size: 20px;
}

#stopSpeechButton {
  background-color: var(--error-color);
}

#stopSpeechButton:hover {
  background-color: #FF1D18;
}

/* ===== INDICATORS ===== */
.listening-indicator {
  display: none;
  color: var(--primary-color);
  font-size: var(--font-size-sm);
  font-weight: 500;
  animation: pulse 1.5s infinite;
}

.typing-indicator {
  display: none;
  padding: var(--space-md) var(--space-lg);
  background-color: var(--surface-secondary);
  border-radius: var(--radius-lg);
  color: var(--text-secondary);
  font-size: var(--font-size-sm);
  font-style: italic;
  margin-bottom: var(--space-md);
  border: 1px solid var(--border-primary);
  animation: pulse 1.5s infinite;
  align-self: flex-start;
  max-width: 200px;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

/* ===== CURSOR TRAIL ===== */
#cursor-trail {
  position: fixed;
  top: 0;
  left: 0;
  pointer-events: none;
  z-index: 9999;
}

.cursor-trail-particle {
  position: absolute;
  width: 8px;
  height: 8px;
  background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
  border-radius: 50%;
  transform-origin: center;
  transition: all 0.1s ease-out;
  mix-blend-mode: multiply;
}

[data-theme="dark"] .cursor-trail-particle {
  mix-blend-mode: screen;
}

.cursor-trail-particle.large {
  width: 12px;
  height: 12px;
}

.cursor-trail-particle.medium {
  width: 8px;
  height: 8px;
}

.cursor-trail-particle.small {
  width: 5px;
  height: 5px;
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 768px) {
  :root {
    --sidebar-width: 260px;
    --header-height: 56px;
  }
  
  .container {
    padding: var(--space-md);
  }
  
  .chatbox {
    max-height: 50vh;
    padding: var(--space-md);
  }
  
  .chat-message {
    max-width: 90%;
    padding: var(--space-sm) var(--space-md);
  }
  
  .input-area {
    padding: var(--space-md);
    gap: var(--space-sm);
  }
  
  #chatInput {
    padding: var(--space-sm) var(--space-md);
  }
  
  #voiceButton,
  #sendButton,
  #stopSpeechButton {
    width: 40px;
    height: 40px;
  }
  
  .header {
    padding: 0 var(--space-md);
  }
  
  .logo {
    font-size: var(--font-size-lg);
  }
  
  .welcome-message {
    padding: var(--space-lg);
  }
  
  .welcome-message h3 {
    font-size: var(--font-size-xl);
  }
  
  .cursor-trail-particle {
    display: none; /* Hide cursor trail on mobile for performance */
  }
}

@media (max-width: 480px) {
  .chat-message {
    max-width: 95%;
  }
  
  .header-controls {
    gap: var(--space-xs);
  }
  
  .header-controls button {
    width: 36px;
    height: 36px;
  }
  
  .input-area {
    flex-wrap: wrap;
  }
  
  .listening-indicator {
    position: absolute;
    top: -30px;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--surface-primary);
    padding: var(--space-xs) var(--space-md);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-primary);
    box-shadow: 0 2px 8px var(--shadow-light);
  }
}

/* ===== FOCUS STYLES ===== */
button:focus-visible,
input:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* ===== SMOOTH TRANSITIONS ===== */
* {
  transition: color var(--transition-fast), 
              background-color var(--transition-fast),
              border-color var(--transition-fast),
              box-shadow var(--transition-fast);
}

/* ===== UTILITIES ===== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ===== PERFORMANCE OPTIMIZATIONS ===== */
.chatbox,
.sidebar,
.header {
  will-change: transform;
}

.cursor-trail-particle {
  will-change: transform, opacity;
}

/* ===== PRINT STYLES ===== */
@media print {
  .sidebar,
  .header-controls,
  .input-area,
  .cursor-trail-particle {
    display: none !important;
  }
  
  .container {
    margin-top: 0;
  }
  
  .chatbox {
    box-shadow: none;
    border: 1px solid #ccc;
    max-height: none;
  }
}