/* ============================================
   Ask Qiao - CSS Styles
   A modern, dark-themed chat interface
   ============================================ */

:root {
  /* Color Palette - Deep space theme */
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a25;
  --bg-hover: #222230;

  --text-primary: #f0f0f5;
  --text-secondary: #a0a0b0;
  --text-muted: #606070;

  --accent-primary: #6366f1;
  --accent-secondary: #818cf8;
  --accent-glow: rgba(99, 102, 241, 0.3);

  --success: #22c55e;
  --error: #ef4444;
  --warning: #f59e0b;

  /* Model colors */
  --openai-color: #10a37f;
  --google-color: #4285f4;

  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;

  /* Border radius */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;

  /* Typography */
  --font-sans: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Safe areas for iOS */
  --safe-top: env(safe-area-inset-top);
  --safe-bottom: env(safe-area-inset-bottom);
}

/* ============================================
   Reset & Base Styles
   ============================================ */

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  min-height: 100dvh;
  overflow: hidden;
}

/* ============================================
   App Container & Layout
   ============================================ */

.app-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  height: 100dvh;
  max-width: 900px;
  margin: 0 auto;
  background: var(--bg-secondary);
}

@media (min-width: 768px) {
  .app-container {
    border-left: 1px solid var(--bg-tertiary);
    border-right: 1px solid var(--bg-tertiary);
  }
}

/* ============================================
   Header
   ============================================ */

.chat-header {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding: var(--spacing-md);
  padding-top: calc(var(--spacing-md) + var(--safe-top));
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--bg-tertiary);
  flex-shrink: 0;
}

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

.header-left h1 {
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.logo-icon {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  object-fit: cover;
  box-shadow: 0 0 15px var(--accent-glow);
}

.header-right {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  width: 100%;
  justify-content: flex-end;
}

.btn-history {
  width: 48px;
  height: 48px;
  margin-right: auto;
}

.admin-link {
  display: none;
}

/* Model Selector */
.model-selector {
  position: relative;
}

.model-selector select {
  appearance: none;
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-hover);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  padding: var(--spacing-sm) var(--spacing-xl) var(--spacing-sm) var(--spacing-md);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.model-selector select:hover {
  border-color: var(--accent-primary);
}

.model-selector select:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.select-arrow {
  position: absolute;
  right: var(--spacing-md);
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  pointer-events: none;
  font-size: 0.75rem;
}

/* Icon Buttons */
.btn-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: transparent;
  border: none;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-icon:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

/* Language Toggle Button */
#lang-toggle span,
.btn-lang-toggle span {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.05em;
}

.btn-lang-toggle {
  position: absolute;
  top: var(--spacing-md);
  right: var(--spacing-md);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-hover);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-lang-toggle:hover {
  border-color: var(--accent-primary);
  color: var(--text-primary);
}

/* ============================================
   Chat Messages Area
   ============================================ */

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-lg);
  scroll-behavior: smooth;
}

/* Welcome Message */
.welcome-message {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--spacing-xl);
  min-height: 100%;
  animation: fadeIn 0.5s ease;
}

.welcome-icon {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  object-fit: cover;
  box-shadow: 0 0 40px var(--accent-glow);
  margin-bottom: var(--spacing-lg);
  animation: pulse 3s infinite;
}

.welcome-message h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.welcome-message p {
  color: var(--text-secondary);
  max-width: 400px;
}

.model-cards {
  display: flex;
  gap: var(--spacing-md);
  margin-top: var(--spacing-xl);
  flex-wrap: wrap;
  justify-content: center;
}

.model-card {
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-hover);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  min-width: 160px;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.model-card:hover {
  border-color: var(--accent-primary);
  transform: translateY(-2px);
}

.model-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  margin-bottom: var(--spacing-sm);
}

.model-badge.openai {
  background: rgba(16, 163, 127, 0.2);
  color: var(--openai-color);
}

.model-badge.google {
  background: rgba(66, 133, 244, 0.2);
  color: var(--google-color);
}

.model-card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.model-card p {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Chat Bubbles */
.message {
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
  animation: slideIn 0.3s ease;
}

.message.user {
  flex-direction: row-reverse;
}

.message-avatar {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  flex-shrink: 0;
}

.message.user .message-avatar {
  background: var(--accent-primary);
  color: white;
}

.message.assistant .message-avatar {
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-hover);
}

.message.assistant .message-avatar.openai {
  color: var(--openai-color);
}

.message.assistant .message-avatar.google {
  color: var(--google-color);
}

.message-avatar .avatar-img {
  width: 100%;
  height: 100%;
  border-radius: var(--radius-md);
  object-fit: cover;
}

.message-content {
  max-width: 75%;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.message.user .message-content {
  align-items: flex-end;
}

.message-bubble {
  padding: var(--spacing-md);
  border-radius: var(--radius-lg);
  line-height: 1.5;
  word-wrap: break-word;
}

.message.user .message-bubble {
  background: var(--accent-primary);
  color: white;
  border-bottom-right-radius: var(--radius-sm);
}

.message.assistant .message-bubble {
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-hover);
  border-bottom-left-radius: var(--radius-sm);
}

.message-meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.message.user .message-meta {
  flex-direction: row-reverse;
}

/* Code blocks in messages */
.message-bubble pre {
  background: var(--bg-primary);
  border-radius: var(--radius-sm);
  padding: var(--spacing-md);
  margin: var(--spacing-sm) 0;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

.message-bubble code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--bg-primary);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

.message-bubble pre code {
  background: none;
  padding: 0;
}

/* Typing indicator */
.typing-indicator {
  display: flex;
  gap: 4px;
  padding: var(--spacing-md);
}

.typing-indicator span {
  width: 8px;
  height: 8px;
  background: var(--text-muted);
  border-radius: 50%;
  animation: bounce 1.4s infinite ease-in-out;
}

.typing-indicator span:nth-child(1) {
  animation-delay: 0s;
}

.typing-indicator span:nth-child(2) {
  animation-delay: 0.2s;
}

.typing-indicator span:nth-child(3) {
  animation-delay: 0.4s;
}

/* ============================================
   Input Area
   ============================================ */

.chat-input-area {
  padding: var(--spacing-md);
  padding-bottom: calc(var(--spacing-md) + var(--safe-bottom));
  background: var(--bg-secondary);
  border-top: 1px solid var(--bg-tertiary);
  flex-shrink: 0;
}

.chat-form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.input-wrapper {
  display: flex;
  align-items: flex-end;
  gap: var(--spacing-sm);
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-hover);
  border-radius: var(--radius-lg);
  padding: var(--spacing-sm);
  transition: all var(--transition-fast);
}

.input-wrapper:focus-within {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.input-wrapper textarea {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.5;
  padding: var(--spacing-sm);
  resize: none;
  max-height: 150px;
  overflow-y: auto;
}

.input-wrapper textarea::placeholder {
  color: var(--text-muted);
}

.input-wrapper textarea:focus {
  outline: none;
}

.btn-send {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: var(--accent-primary);
  border: none;
  border-radius: var(--radius-md);
  color: white;
  cursor: pointer;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.btn-send:hover:not(:disabled) {
  background: var(--accent-secondary);
  transform: scale(1.05);
}

.btn-send:disabled {
  background: var(--bg-hover);
  color: var(--text-muted);
  cursor: not-allowed;
}

.input-footer {
  display: flex;
  justify-content: space-between;
  padding: 0 var(--spacing-sm);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.current-model strong {
  color: var(--accent-secondary);
}

/* ============================================
   Prompt Builder
   ============================================ */

.prompt-builder-toggle {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
}

.prompt-builder-desc {
  color: var(--text-muted);
  font-size: 0.8rem;
  font-style: italic;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.btn-prompt-builder {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-hover);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  padding: var(--spacing-xs) var(--spacing-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
  flex-shrink: 0;
}

.btn-icon-img {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  object-fit: cover;
}

.btn-prompt-builder:hover {
  border-color: var(--accent-primary);
  color: var(--text-primary);
  background: var(--bg-hover);
}

.prompt-builder {
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-hover);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  margin-bottom: var(--spacing-md);
  animation: slideDown 0.3s ease;
  max-height: 400px;
  overflow-y: auto;
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.prompt-builder-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-lg);
}

.prompt-builder-header h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.btn-icon-small {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-icon-small:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.prompt-form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.prompt-field {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.prompt-field label {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
}

.label-text {
  font-family: var(--font-mono);
  color: var(--accent-secondary);
}

.label-required {
  color: var(--error);
  font-size: 0.75rem;
}

.label-optional {
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 400;
}

.prompt-field textarea {
  background: var(--bg-secondary);
  border: 1px solid var(--bg-hover);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  line-height: 1.5;
  padding: var(--spacing-md);
  resize: vertical;
  min-height: 60px;
  transition: all var(--transition-fast);
}

.prompt-field textarea::placeholder {
  color: var(--text-muted);
}

.prompt-field textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.prompt-field.optional textarea {
  border-color: var(--bg-hover);
}

.prompt-field.optional textarea:focus {
  border-color: var(--accent-primary);
}

.field-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: -4px;
}

.prompt-builder-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: flex-end;
  padding-top: var(--spacing-sm);
  border-top: 1px solid var(--bg-hover);
}

.btn-secondary {
  background: var(--bg-secondary);
  border: 1px solid var(--bg-hover);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  padding: var(--spacing-sm) var(--spacing-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-secondary:hover {
  border-color: var(--accent-primary);
  color: var(--text-primary);
  background: var(--bg-hover);
}

.prompt-builder-actions .btn-primary {
  background: var(--accent-primary);
  border: none;
  border-radius: var(--radius-md);
  color: white;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  padding: var(--spacing-sm) var(--spacing-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.prompt-builder-actions .btn-primary:hover {
  background: var(--accent-secondary);
  transform: translateY(-1px);
}

/* ============================================
   Login Page
   ============================================ */

.login-page {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  min-height: 100dvh;
  padding: var(--spacing-lg);
  background: var(--bg-primary);
  overflow: auto;
}

.login-container {
  position: relative;
  width: 100%;
  max-width: 400px;
}

.login-glow {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  pointer-events: none;
  animation: pulse 4s infinite;
}

.login-card {
  position: relative;
  background: var(--bg-secondary);
  border: 1px solid var(--bg-tertiary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  animation: fadeIn 0.5s ease;
}

.login-header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.logo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.logo .logo-icon {
  width: 48px;
  height: 48px;
}

.logo h1 {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.tagline {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Auth Tabs */
.auth-tabs {
  display: flex;
  gap: var(--spacing-xs);
  margin-bottom: var(--spacing-lg);
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 4px;
}

.auth-tab {
  flex: 1;
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  padding: var(--spacing-sm) var(--spacing-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.auth-tab:hover {
  color: var(--text-primary);
}

.auth-tab.active {
  background: var(--bg-secondary);
  color: var(--text-primary);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

.login-form {
  display: none;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.login-form.active {
  display: flex;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

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

.form-group input[type="text"],
.form-group input[type="password"] {
  background: var(--bg-tertiary);
  border: 1px solid var(--bg-hover);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 1rem;
  padding: var(--spacing-md);
  transition: all var(--transition-fast);
}

.form-group input[type="password"] {
  font-family: var(--font-sans);
  letter-spacing: 0.1em;
}

.form-group input::placeholder {
  color: var(--text-muted);
}

.form-group input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.input-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.btn-primary {
  position: relative;
  background: var(--accent-primary);
  border: none;
  border-radius: var(--radius-md);
  color: white;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 500;
  padding: var(--spacing-md) var(--spacing-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  overflow: hidden;
}

.btn-primary:hover:not(:disabled) {
  background: var(--accent-secondary);
  transform: translateY(-1px);
}

.btn-primary:disabled {
  opacity: 0.7;
  cursor: not-allowed;
}

.btn-primary.loading .btn-text {
  opacity: 0;
}

.btn-primary.loading .btn-loader {
  display: block;
}

.btn-loader {
  display: none;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 20px;
  height: 20px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.error-message {
  color: var(--error);
  font-size: 0.875rem;
  text-align: center;
  min-height: 1.5em;
}

.login-footer {
  text-align: center;
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--bg-tertiary);
}

.login-footer p {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ============================================
   Animations
   ============================================ */

@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

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

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {

  0%,
  100% {
    opacity: 1;
  }

  50% {
    opacity: 0.6;
  }
}

@keyframes bounce {

  0%,
  80%,
  100% {
    transform: translateY(0);
  }

  40% {
    transform: translateY(-6px);
  }
}

@keyframes spin {
  to {
    transform: translate(-50%, -50%) rotate(360deg);
  }
}

/* ============================================
   History Sidebar
   ============================================ */

.history-sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: 300px;
  height: 100vh;
  height: 100dvh;
  background: var(--bg-secondary);
  border-right: 1px solid var(--bg-tertiary);
  transform: translateX(-100%);
  transition: transform var(--transition-normal);
  z-index: 1000;
  display: flex;
  flex-direction: column;
}

.history-sidebar.open {
  transform: translateX(0);
}

.history-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
  z-index: 999;
}

.history-overlay.visible {
  opacity: 1;
  visibility: visible;
}

.history-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md);
  padding-top: calc(var(--spacing-md) + var(--safe-top));
  border-bottom: 1px solid var(--bg-tertiary);
  flex-shrink: 0;
}

.history-header h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

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

.history-empty {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  color: var(--text-muted);
  font-size: 0.875rem;
}

.history-group {
  margin-bottom: var(--spacing-md);
}

.history-group-title {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: var(--spacing-sm) var(--spacing-sm);
}

.history-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.history-item:hover {
  background: var(--bg-tertiary);
}

.history-item.active {
  background: var(--bg-hover);
}

.history-item-icon {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: 0.875rem;
  flex-shrink: 0;
}

.history-item-content {
  flex: 1;
  min-width: 0;
}

.history-item-title {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.history-item-meta {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.history-item-delete {
  position: absolute;
  right: var(--spacing-sm);
  opacity: 0.5;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: var(--spacing-xs);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.history-item:hover .history-item-delete {
  opacity: 1;
}

.history-item-delete:hover {
  color: var(--error);
  background: var(--bg-hover);
}

@media (max-width: 480px) {
  .history-sidebar {
    width: 100%;
  }
}

/* ============================================
   Scrollbar Styling
   ============================================ */

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

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--bg-hover);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* ============================================
   Responsive Adjustments
   ============================================ */

/* Hide description on tablets and phones */
@media (max-width: 600px) {
  .prompt-builder-desc {
    display: none;
  }
}

@media (max-width: 480px) {
  .chat-header {
    padding: var(--spacing-xs) var(--spacing-sm);
    padding-top: calc(var(--spacing-xs) + var(--safe-top));
    gap: var(--spacing-xs);
  }

  /* Hide title text on mobile, keep only logo icon */
  .header-left h1 {
    display: none;
  }

  .header-left {
    flex-shrink: 0;
  }

  .logo-icon {
    width: 28px;
    height: 28px;
  }

  .header-right {
    flex: 1;
    justify-content: flex-end;
    gap: var(--spacing-xs);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }

  .model-selector select {
    font-size: 0.75rem;
    padding: 6px 24px 6px 8px;
    max-width: 100px;
  }

  .select-arrow {
    right: var(--spacing-sm);
  }

  .btn-icon {
    width: 32px;
    height: 32px;
    flex-shrink: 0;
  }

  .btn-icon svg {
    width: 16px;
    height: 16px;
  }

  #lang-toggle span {
    font-size: 0.65rem;
  }

  .chat-messages {
    padding: var(--spacing-md);
  }

  .message-content {
    max-width: 85%;
  }

  .model-cards {
    flex-direction: column;
    width: 100%;
  }

  .model-card {
    min-width: unset;
  }

  .prompt-builder {
    padding: var(--spacing-md);
  }

  .prompt-builder-header h3 {
    font-size: 0.9rem;
  }

  .prompt-field textarea {
    font-size: 0.8rem;
    padding: var(--spacing-sm);
  }

  .prompt-builder-actions {
    flex-direction: column;
  }

  .prompt-builder-actions .btn-secondary,
  .prompt-builder-actions .btn-primary {
    width: 100%;
  }
}

/* Extra small screens (iPhone SE, etc.) */
@media (max-width: 375px) {
  .model-selector select {
    max-width: 80px;
    font-size: 0.7rem;
    padding: 5px 20px 5px 6px;
  }

  .btn-icon {
    width: 28px;
    height: 28px;
  }

  .btn-icon svg {
    width: 14px;
    height: 14px;
  }

  .header-right {
    gap: 2px;
  }
}