/* ===== PUSHAI ENTERPRISE DESIGN SYSTEM v2.1 ===== */

/* CSS Custom Properties - Design Tokens */
:root {
  /* Color System - Light Theme */
  --color-white: #ffffff;
  --color-gray-50: #fafbfc;
  --color-gray-100: #f2f4f7;
  --color-gray-200: #e4e7ec;
  --color-gray-300: #d0d5dd;
  --color-gray-400: #98a2b3;
  --color-gray-500: #667085;
  --color-gray-600: #475467;
  --color-gray-700: #344054;
  --color-gray-800: #182230;
  --color-gray-900: #101828;
  
  /* Brand Colors */
  --color-primary-50: #eff8ff;
  --color-primary-100: #d1e9ff;
  --color-primary-200: #b2ddff;
  --color-primary-300: #84caff;
  --color-primary-400: #53b1fd;
  --color-primary-500: #2e90fa;
  --color-primary-600: #1570ef;
  --color-primary-700: #175cd3;
  --color-primary-800: #1849a9;
  --color-primary-900: #194185;
  
  /* Semantic Colors */
  --color-success-500: #12b76a;
  --color-success-600: #039855;
  --color-warning-500: #f79009;
  --color-warning-600: #dc6803;
  --color-error-500: #f04438;
  --color-error-600: #d92d20;
  
  /* Typography Scale */
  --font-family-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-family-mono: 'JetBrains Mono', 'SF Mono', Monaco, 'Cascadia Code', monospace;
  
  --font-size-xs: 0.75rem;    /* 12px */
  --font-size-sm: 0.875rem;   /* 14px */
  --font-size-base: 1rem;     /* 16px */
  --font-size-lg: 1.125rem;   /* 18px */
  --font-size-xl: 1.25rem;    /* 20px */
  --font-size-2xl: 1.5rem;    /* 24px */
  --font-size-3xl: 1.875rem;  /* 30px */
  --font-size-4xl: 2.25rem;   /* 36px */
  
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  
  /* Spacing System */
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-5: 1.25rem;   /* 20px */
  --space-6: 1.5rem;    /* 24px */
  --space-8: 2rem;      /* 32px */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */
  --space-20: 5rem;     /* 80px */
  
  /* Border Radius */
  --radius-none: 0;
  --radius-sm: 0.125rem;   /* 2px */
  --radius-base: 0.25rem;  /* 4px */
  --radius-md: 0.375rem;   /* 6px */
  --radius-lg: 0.5rem;     /* 8px */
  --radius-xl: 0.75rem;    /* 12px */
  --radius-2xl: 1rem;      /* 16px */
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-xs: 0 1px 2px 0 rgb(16 24 40 / 0.05);
  --shadow-sm: 0 1px 3px 0 rgb(16 24 40 / 0.1), 0 1px 2px -1px rgb(16 24 40 / 0.1);
  --shadow-md: 0 4px 8px -2px rgb(16 24 40 / 0.1), 0 2px 4px -2px rgb(16 24 40 / 0.06);
  --shadow-lg: 0 12px 16px -4px rgb(16 24 40 / 0.08), 0 4px 6px -2px rgb(16 24 40 / 0.03);
  --shadow-xl: 0 20px 24px -4px rgb(16 24 40 / 0.08), 0 8px 8px -4px rgb(16 24 40 / 0.03);
  --shadow-2xl: 0 24px 48px -12px rgb(16 24 40 / 0.18);
  
  /* Z-Index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
  --z-toast: 1080;
  
  /* Layout */
  --sidebar-width: 280px;
  --sidebar-width-collapsed: 64px;
  --topbar-height: 64px;
  --max-content-width: 1200px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;
}

/* Dark Theme - Default and Only Theme */
:root {
  /* Override with dark theme colors as default */
  --color-white: #0a0e16;
  --color-gray-50: #0a0e16;
  --color-gray-100: #151922;
  --color-gray-200: #1f242d;
  --color-gray-300: #2a3038;
  --color-gray-400: #4a5568;
  --color-gray-500: #718096;
  --color-gray-600: #a0aec0;
  --color-gray-700: #cbd5e0;
  --color-gray-800: #e2e8f0;
  --color-gray-900: #f7fafc;
  
  /* Enhanced dark theme colors */
  --color-surface: #151922;
  --color-surface-elevated: #1f242d;
  --color-surface-hover: #2a3038;
  --color-border-subtle: #2a3038;
  --color-border-default: #4a5568;
  
  /* Refined brand colors for dark theme */
  --color-primary-50: #0f1419;
  --color-primary-100: #1a2332;
  --color-primary-200: #2d3748;
  --color-primary-300: #4299e1;
  --color-primary-400: #63b3ed;
  --color-primary-500: #4299e1;
  --color-primary-600: #3182ce;
  --color-primary-700: #2c5282;
  --color-primary-800: #2a4365;
  --color-primary-900: #1a365d;
}

/* ===== RESET & BASE STYLES ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-sans);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-gray-900);
  background-color: var(--color-white);
  overflow-x: hidden;
}

/* Remove default button styles */
button {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
  margin: 0;
  padding: 0;
  border: none;
  background: none;
  cursor: pointer;
  color: inherit;
}

/* Remove default input styles */
input,
textarea,
select {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
  margin: 0;
  padding: 0;
  border: none;
  background: none;
  color: inherit;
}

/* Remove default link styles */
a {
  color: inherit;
  text-decoration: none;
}

/* Remove default list styles */
ul,
ol {
  list-style: none;
  margin: 0;
  padding: 0;
}

/* ===== LOADING SCREEN ===== */
.loading-overlay {
  position: fixed;
  inset: 0;
  background: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-modal);
  transition: opacity var(--transition-slow), visibility var(--transition-slow);
}

.loading-overlay[aria-hidden="true"] {
  opacity: 0;
  visibility: hidden;
}

.loading-spinner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
}

.spinner-ring {
  width: 40px;
  height: 40px;
  border: 3px solid var(--color-gray-200);
  border-top: 3px solid var(--color-primary-600);
  border-radius: var(--radius-full);
  animation: spin 1s linear infinite;
}

.loading-text {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-gray-600);
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* ===== LAYOUT ===== */
.app {
  display: flex;
  height: 100vh;
  background: var(--color-gray-50);
}

/* ===== SIDEBAR ===== */
.sidebar {
  width: var(--sidebar-width);
  background: var(--color-white);
  border-right: 1px solid var(--color-gray-200);
  display: flex;
  flex-direction: column;
  transition: width var(--transition-base);
  z-index: var(--z-sticky);
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--color-gray-200);
  min-height: var(--topbar-height);
}

.logo-section {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.logo-text {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-gray-900);
}

.version-badge {
  background: var(--color-primary-50);
  color: var(--color-primary-700);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-base);
}

.sidebar-toggle {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gray-500);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.sidebar-toggle:hover {
  background: var(--color-gray-100);
  color: var(--color-gray-700);
}

/* Sidebar Navigation */
.sidebar-nav {
  flex: 1;
  padding: var(--space-4) var(--space-3);
  overflow-y: auto;
}

.nav-section {
  margin-bottom: var(--space-6);
}

.section-title {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  color: var(--color-gray-500);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-3);
  padding: 0 var(--space-3);
}

.nav-item {
  display: flex;
  align-items: center;
  width: 100%;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-3);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-gray-700);
  transition: all var(--transition-fast);
  margin-bottom: var(--space-1);
}

.nav-item:hover {
  background: var(--color-gray-100);
  color: var(--color-gray-900);
}

.nav-item.active {
  background: var(--color-primary-50);
  color: var(--color-primary-700);
}

.nav-item svg {
  flex-shrink: 0;
  opacity: 0.7;
}

.nav-item.active svg {
  opacity: 1;
}

/* Model Items */
.model-item {
  position: relative;
}

.model-indicator {
  width: 6px;
  height: 6px;
  border-radius: var(--radius-full);
  background: var(--color-gray-300);
  flex-shrink: 0;
}

.model-item.active .model-indicator {
  background: var(--color-success-500);
}

.model-status {
  margin-left: auto;
  font-size: var(--font-size-xs);
  color: var(--color-success-500);
}

/* Sidebar Footer - Authentication Section */
.sidebar-footer {
  border-top: 1px solid var(--color-border-subtle);
  padding: var(--space-4);
}

.auth-section {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.auth-buttons {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.auth-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-lg);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-fast);
  position: relative;
  overflow: hidden;
}

/* Remove shimmer animation */
.auth-btn::before { display: none; }

/* Auth buttons: white, no animation */
.login-btn,
.signup-btn {
  background: #ffffff;
  color: #0a0e16;
  border: 1px solid var(--color-border-default);
  transition: none;
}

.login-btn:hover,
.signup-btn:hover {
  background: #ffffff;
  color: #0a0e16;
  border-color: var(--color-border-default);
  transform: none;
  box-shadow: none;
}

.auth-btn svg {
  flex-shrink: 0;
  opacity: 0.8;
}

.auth-btn:hover svg {
  opacity: 1;
}

.auth-footer {
  text-align: center;
  padding-top: var(--space-2);
  border-top: 1px solid var(--color-border-subtle);
}

.auth-info {
  font-size: var(--font-size-xs);
  color: var(--color-gray-500);
  font-weight: var(--font-weight-medium);
}

/* ===== MAIN CONTENT ===== */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

/* Top Bar */
.top-bar {
  height: var(--topbar-height);
  background: var(--color-white);
  border-bottom: 1px solid var(--color-gray-200);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-6);
  z-index: var(--z-sticky);
}

.top-bar-left,
.top-bar-right {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.mobile-menu-btn {
  display: none;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  color: var(--color-gray-600);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.mobile-menu-btn:hover {
  background: var(--color-gray-100);
  color: var(--color-gray-900);
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-sm);
}

.current-model {
  font-weight: var(--font-weight-semibold);
  color: var(--color-gray-900);
}

.separator {
  color: var(--color-gray-400);
}

.session-info {
  color: var(--color-gray-600);
}

/* Usage Indicator */
.usage-indicator {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--font-size-sm);
}

.usage-bar {
  width: 80px;
  height: 4px;
  background: var(--color-gray-200);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.usage-fill {
  height: 100%;
  background: var(--color-primary-500);
  border-radius: var(--radius-full);
  transition: width var(--transition-base);
}

.usage-text {
  color: var(--color-gray-600);
  font-weight: var(--font-weight-medium);
  white-space: nowrap;
}

/* Top Bar Buttons */
.settings-btn,
.help-btn {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gray-600);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  position: relative;
}

.settings-btn:hover,
.help-btn:hover {
  background: var(--color-surface-hover);
  color: var(--color-gray-300);
  transform: scale(1.05);
}

.settings-btn:active,
.help-btn:active {
  transform: scale(0.95);
}

/* ===== CHAT WORKSPACE ===== */
.chat-workspace {
  flex: 1;
  display: flex;
  justify-content: center;
  overflow: hidden;
}

.chat-container {
  width: 100%;
  max-width: var(--max-content-width);
  display: flex;
  flex-direction: column;
  height: 100%;
}

/* Messages Area */
.messages-area {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-6) var(--space-6) 0;
}

.messages {
  display: flex;
  flex-direction: column;
  gap: var(--space-8);
  min-height: 100%;
}

/* Welcome Section */
.welcome-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  flex: 1;
  padding: var(--space-12) var(--space-6);
}

.welcome-header {
  margin-bottom: var(--space-10);
}

.ai-avatar-large {
  width: 64px;
  height: 64px;
  background: linear-gradient(135deg, var(--color-primary-500), var(--color-primary-600));
  border-radius: var(--radius-2xl);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-white);
  margin: 0 auto var(--space-6);
  box-shadow: var(--shadow-lg);
}

.welcome-header h2 {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-gray-900);
  margin-bottom: var(--space-3);
  line-height: var(--line-height-tight);
}

.welcome-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-gray-600);
  line-height: var(--line-height-relaxed);
  max-width: 600px;
}

/* Quick Actions */
.quick-actions {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--space-4);
  width: 100%;
  max-width: 800px;
}

.quick-action-btn {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-5);
  background: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-xl);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-gray-700);
  text-align: left;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-sm);
}

.quick-action-btn:hover {
  border-color: var(--color-primary-300);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.quick-action-btn svg {
  flex-shrink: 0;
  color: var(--color-primary-500);
}

/* Message Styles */
.message {
  display: flex;
  gap: var(--space-4);
  animation: messageSlideIn var(--transition-base) ease-out;
}

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

.message-avatar {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  flex-shrink: 0;
  margin-top: var(--space-1);
}

.message.user .message-avatar {
  background: var(--color-primary-500);
  color: var(--color-white);
}

.message.ai .message-avatar {
  background: var(--color-gray-100);
  color: var(--color-gray-700);
}

.message-content {
  flex: 1;
  max-width: calc(100% - 48px);
}

.message-text {
  font-size: var(--font-size-base);
  line-height: var(--line-height-relaxed);
  color: var(--color-gray-900);
}

.message.user .message-text {
  background: var(--color-primary-500);
  color: var(--color-white);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-xl);
  margin-left: auto;
  max-width: fit-content;
}

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

/* ===== INPUT SECTION ===== */
.input-section {
  padding: var(--space-6);
  background: var(--color-white);
  border-top: 1px solid var(--color-gray-200);
}

.input-container {
  max-width: var(--max-content-width);
  margin: 0 auto;
}

.input-wrapper {
  position: relative;
  background: var(--color-white);
  border: 2px solid var(--color-gray-300);
  border-radius: var(--radius-2xl);
  padding: var(--space-4);
  transition: all var(--transition-fast);
  display: flex;
  align-items: flex-end;
  gap: var(--space-3);
  box-shadow: var(--shadow-sm);
}

.input-wrapper:focus-within {
  border-color: var(--color-primary-500);
  box-shadow: var(--shadow-md), 0 0 0 4px var(--color-primary-100);
}

.attachment-btn {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gray-500);
  border-radius: var(--radius-lg);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.attachment-btn:hover {
  background: var(--color-gray-100);
  color: var(--color-gray-700);
}

.file-input {
  display: none;
}

.textarea-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  min-width: 0;
}

#chat-input {
  width: 100%;
  background: transparent;
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-gray-900);
  resize: none;
  min-height: 24px;
  max-height: 200px;
  outline: none;
}

#chat-input::placeholder {
  color: var(--color-gray-500);
}

.input-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: var(--space-3);
}

.character-count {
  font-size: var(--font-size-xs);
  color: var(--color-gray-500);
  font-family: var(--font-family-mono);
  font-weight: var(--font-weight-medium);
}

/* File Preview */
.file-preview-area {
  margin-bottom: var(--space-4);
}

.file-preview-grid {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.file-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--color-gray-50);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  padding: var(--space-2) var(--space-3);
  font-size: var(--font-size-sm);
  max-width: 200px;
}

.file-item.image img {
  width: 32px;
  height: 32px;
  object-fit: cover;
  border-radius: var(--radius-base);
  flex-shrink: 0;
}

.file-name {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  color: var(--color-gray-700);
}

.remove-file-btn {
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gray-500);
  border-radius: var(--radius-base);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.remove-file-btn:hover {
  background: var(--color-error-100);
  color: var(--color-error-600);
}

/* Input Footer */
.input-footer {
  margin-top: var(--space-4);
  text-align: center;
}

.footer-info {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-6);
  font-size: var(--font-size-xs);
  color: var(--color-gray-500);
}

.footer-links {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.footer-link {
  color: var(--color-gray-500);
  transition: color var(--transition-fast);
}

.footer-link:hover {
  color: var(--color-gray-700);
}

/* ===== SCROLLBAR STYLING ===== */
.messages-area::-webkit-scrollbar {
  width: 8px;
}

.messages-area::-webkit-scrollbar-track {
  background: transparent;
}

.messages-area::-webkit-scrollbar-thumb {
  background: var(--color-gray-300);
  border-radius: var(--radius-full);
}

.messages-area::-webkit-scrollbar-thumb:hover {
  background: var(--color-gray-400);
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 1024px) {
  .sidebar {
    width: var(--sidebar-width-collapsed);
  }
  
  .logo-text,
  .version-badge,
  .nav-item span,
  .section-title,
  .user-info {
    display: none;
  }
  
  .sidebar-header {
    justify-content: center;
  }
  
  .user-profile {
    justify-content: center;
  }
}

@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    left: -280px;
    width: var(--sidebar-width);
    height: 100vh;
    z-index: var(--z-modal);
    transition: left var(--transition-base);
    background: var(--color-white);
    border-right: 1px solid var(--color-gray-200);
    box-shadow: var(--shadow-xl);
    overflow-y: auto;
  }
  
  .sidebar.open {
    left: 0;
  }
  
  /* Mobile backdrop */
  .sidebar.open::before {
    content: '';
    position: fixed;
    top: 0;
    left: 280px;
    right: 0;
    bottom: 0;
    background: rgba(10, 14, 22, 0.5);
    z-index: -1;
  }
  
  .mobile-menu-btn {
    display: flex;
  }
  
  /* Reset collapsed state on mobile */
  .sidebar.collapsed {
    width: var(--sidebar-width);
    left: -280px;
  }
  
  .sidebar.collapsed.open {
    left: 0;
  }
  
  /* Show all nav items on mobile */
  .logo-text,
  .version-badge,
  .nav-item span,
  .section-title,
  .auth-section {
    display: block !important;
  }
  
  .sidebar-header {
    justify-content: space-between;
  }
  
  /* Ensure sidebar toggle is visible on mobile */
  .sidebar-toggle {
    display: flex !important;
  }
  
  /* Sidebar scrolling */
  .sidebar-nav {
    padding-bottom: var(--space-20);
  }
  
  .sidebar-footer {
    position: sticky;
    bottom: 0;
    background: var(--color-white);
    border-top: 1px solid var(--color-border-subtle);
    margin-top: auto;
  }
  
  .usage-indicator {
    display: none;
  }
  
  .quick-actions {
    grid-template-columns: 1fr;
  }
  
  .messages-area {
    padding: var(--space-4) var(--space-4) 0;
  }
  
  .input-section {
    padding: var(--space-4);
  }
  
  .footer-info {
    flex-direction: column;
    gap: var(--space-2);
  }
}

@media (max-width: 480px) {
  .welcome-header h2 {
    font-size: var(--font-size-2xl);
  }
  
  .welcome-subtitle {
    font-size: var(--font-size-base);
  }
  
  .input-actions {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-2);
  }
  
  .send-btn {
    justify-content: center;
  }
}

/* ===== ACCESSIBILITY ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Focus visible */
.nav-item:focus-visible,
.quick-action-btn:focus-visible,
.send-btn:focus-visible,
.attachment-btn:focus-visible,
.theme-toggle:focus-visible,
.help-btn:focus-visible {
  outline: 2px solid var(--color-primary-500);
  outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  :root {
    --color-gray-200: #000000;
    --color-gray-300: #000000;
    --shadow-sm: none;
    --shadow-md: none;
    --shadow-lg: none;
  }
}

/* ===== MODAL SYSTEM - CORPORATE DESIGN ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(10, 14, 22, 0.85);
  backdrop-filter: blur(6px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-modal);
  padding: var(--space-4);
  animation: modalFadeIn 0.15s ease-out;
}

.modal-content {
  background: var(--color-surface-elevated);
  border: 2px solid var(--color-border-default);
  border-radius: var(--radius-none);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3), 0 0 0 1px rgba(255, 255, 255, 0.05);
  width: 100%;
  max-width: 420px;
  animation: modalSlideIn 0.2s ease-out;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-8) var(--space-8) var(--space-6);
  border-bottom: 2px solid var(--color-border-subtle);
  background: var(--color-white);
}

.modal-header h2 {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-gray-900);
  margin: 0;
  letter-spacing: -0.02em;
}

.modal-close {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gray-500);
  border-radius: var(--radius-none);
  border: 1px solid var(--color-border-default);
  background: var(--color-white);
  font-size: 18px;
  font-weight: var(--font-weight-bold);
  transition: all var(--transition-fast);
}

.modal-close:hover {
  background: var(--color-gray-100);
  color: var(--color-gray-700);
  border-color: var(--color-gray-400);
}

.auth-form {
  padding: var(--space-8);
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
  background: var(--color-white);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.form-group label {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  color: var(--color-gray-800);
  text-transform: uppercase;
  letter-spacing: 0.02em;
  font-size: var(--font-size-xs);
}

.form-group input {
  padding: var(--space-4) var(--space-5);
  border: 2px solid var(--color-border-default);
  border-radius: var(--radius-none);
  background: var(--color-white);
  color: var(--color-gray-900);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-fast);
  min-height: 48px;
}

.form-group input:focus {
  outline: none;
  border-color: var(--color-primary-600);
  box-shadow: inset 0 0 0 1px var(--color-primary-600);
  background: var(--color-primary-50);
}

.form-group input::placeholder {
  color: var(--color-gray-500);
  font-weight: var(--font-weight-normal);
}

.auth-submit-btn {
  background: var(--color-primary-600);
  color: var(--color-white);
  padding: var(--space-4) var(--space-6);
  border-radius: var(--radius-none);
  border: 2px solid var(--color-primary-600);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.02em;
  transition: all var(--transition-fast);
  margin-top: var(--space-4);
  min-height: 52px;
}

.auth-submit-btn:hover {
  background: var(--color-primary-700);
  border-color: var(--color-primary-700);
  transform: none;
  box-shadow: inset 0 0 0 2px var(--color-primary-800);
}

.auth-switch {
  padding: var(--space-6) var(--space-8) var(--space-8);
  text-align: center;
  border-top: 2px solid var(--color-border-subtle);
  background: var(--color-gray-50);
  font-size: var(--font-size-sm);
  color: var(--color-gray-700);
  font-weight: var(--font-weight-medium);
}

.switch-btn {
  color: var(--color-primary-600);
  font-weight: var(--font-weight-bold);
  margin-left: var(--space-2);
  transition: color var(--transition-fast);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.switch-btn:hover {
  color: var(--color-primary-700);
  text-decoration: none;
}

@keyframes modalFadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes modalSlideIn {
  from {
    opacity: 0;
    transform: translateY(-20px) scale(0.95);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

/* ===== NOTIFICATION SYSTEM ===== */
.notification {
  position: fixed;
  top: var(--space-6);
  right: var(--space-6);
  background: var(--color-surface-elevated);
  border: 1px solid var(--color-border-default);
  border-radius: var(--radius-lg);
  padding: var(--space-4) var(--space-5);
  box-shadow: var(--shadow-lg);
  z-index: var(--z-toast);
  max-width: 400px;
  animation: notificationSlideIn 0.3s ease-out;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
}

.notification.info {
  border-left: 4px solid var(--color-primary-500);
  color: var(--color-gray-700);
}

.notification.success {
  border-left: 4px solid var(--color-success-500);
  color: var(--color-gray-700);
}

.notification.error {
  border-left: 4px solid var(--color-error-500);
  color: var(--color-gray-700);
}

.notification.fade-out {
  animation: notificationFadeOut 0.3s ease-out forwards;
}

@keyframes notificationSlideIn {
  from {
    opacity: 0;
    transform: translateX(100%);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes notificationFadeOut {
  to {
    opacity: 0;
    transform: translateX(100%);
  }
}

/* ===== UTILITY CLASSES ===== */
.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;
}

.no-js .loading-overlay {
  display: none;
}