/* ========================================
   Chatty — Design System
   Premium dark theme with glassmorphism
   ======================================== */

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

:root {
  /* Background */
  --bg-primary: #07080f;
  --bg-secondary: #0d0e1a;
  --bg-tertiary: #131425;
  --bg-elevated: #1a1b2e;
  --bg-glass: rgba(19, 20, 37, 0.7);
  --bg-glass-hover: rgba(26, 27, 46, 0.85);

  /* Text */
  --text-primary: #e8e9f0;
  --text-secondary: #9698ab;
  --text-tertiary: #5f6175;
  --text-inverse: #07080f;

  /* Subject Accent Colors */
  --nano-color: #34d399;
  --nano-glow: rgba(52, 211, 153, 0.15);
  --nano-bg: rgba(52, 211, 153, 0.08);

  --bio-color: #22d3ee;
  --bio-glow: rgba(34, 211, 238, 0.15);
  --bio-bg: rgba(34, 211, 238, 0.08);

  --biochem-color: #2dd4bf;
  --biochem-glow: rgba(45, 212, 191, 0.15);
  --biochem-bg: rgba(45, 212, 191, 0.08);

  --aiml-color: #a78bfa;
  --aiml-glow: rgba(167, 139, 250, 0.15);
  --aiml-bg: rgba(167, 139, 250, 0.08);

  --cogsci-color: #fbbf24;
  --cogsci-glow: rgba(251, 191, 36, 0.15);
  --cogsci-bg: rgba(251, 191, 36, 0.08);

  --nbic-color: #f472b6;
  --nbic-glow: rgba(244, 114, 182, 0.15);
  --nbic-bg: rgba(244, 114, 182, 0.08);

  --exam-color: #fb923c;

  /* Accent */
  --accent: #a78bfa;
  --accent-hover: #c4b5fd;
  --accent-glow: rgba(167, 139, 250, 0.3);

  /* Borders */
  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-medium: rgba(255, 255, 255, 0.1);
  --border-strong: rgba(255, 255, 255, 0.15);

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 40px rgba(167, 139, 250, 0.1);

  /* Layout */
  --sidebar-width: 300px;
  --header-height: 60px;
  --input-area-height: auto;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

/* --------------- Scrollbar --------------- */
::-webkit-scrollbar {
  width: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--border-medium);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover {
  background: var(--border-strong);
}

/* --------------- App Layout --------------- */
.app {
  display: flex;
  height: 100vh;
  width: 100vw;
  overflow: hidden;
}

/* --------------- Sidebar --------------- */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  height: 100vh;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: transform var(--transition-base);
  z-index: 100;
}

.sidebar-header {
  padding: 20px 16px;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.logo-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  overflow: hidden;
  box-shadow: 0 0 20px rgba(167, 139, 250, 0.3);
  animation: logoPulse 3s ease-in-out infinite;
}

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

@keyframes logoPulse {
  0%, 100% { box-shadow: 0 0 20px rgba(167, 139, 250, 0.3); }
  50% { box-shadow: 0 0 30px rgba(167, 139, 250, 0.5); }
}

.logo-text {
  min-width: 0;
}

.logo-text h1 {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  white-space: nowrap;
}

.logo-subtitle {
  font-size: 11px;
  color: var(--text-tertiary);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.new-chat-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-medium);
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.new-chat-btn:hover {
  background: var(--bg-glass-hover);
  color: var(--text-primary);
  border-color: var(--accent);
  box-shadow: 0 0 12px var(--accent-glow);
}

/* Sidebar Sections */
.sidebar-section {
  padding: 16px;
  overflow-y: auto;
  flex: 1;
}

.sidebar-section-title {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-tertiary);
  margin-bottom: 10px;
}

.topic-chips {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.topic-chip {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: left;
  width: 100%;
}

.topic-chip:hover {
  background: var(--bg-glass-hover);
  color: var(--text-primary);
}

.chip-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

.topic-chip.nano .chip-dot { background: var(--nano-color); box-shadow: 0 0 8px var(--nano-glow); }
.topic-chip.bio .chip-dot { background: var(--bio-color); box-shadow: 0 0 8px var(--bio-glow); }
.topic-chip.biochem .chip-dot { background: var(--biochem-color); box-shadow: 0 0 8px var(--biochem-glow); }
.topic-chip.aiml .chip-dot { background: var(--aiml-color); box-shadow: 0 0 8px var(--aiml-glow); }
.topic-chip.cogsci .chip-dot { background: var(--cogsci-color); box-shadow: 0 0 8px var(--cogsci-glow); }
.topic-chip.nbic .chip-dot { background: var(--nbic-color); box-shadow: 0 0 8px var(--nbic-glow); }

.topic-chip.nano:hover { background: var(--nano-bg); color: var(--nano-color); }
.topic-chip.bio:hover { background: var(--bio-bg); color: var(--bio-color); }
.topic-chip.biochem:hover { background: var(--biochem-bg); color: var(--biochem-color); }
.topic-chip.aiml:hover { background: var(--aiml-bg); color: var(--aiml-color); }
.topic-chip.cogsci:hover { background: var(--cogsci-bg); color: var(--cogsci-color); }
.topic-chip.nbic:hover { background: var(--nbic-bg); color: var(--nbic-color); }

.topic-chip.exam {
  color: var(--text-secondary);
}
.topic-chip.exam:hover {
  background: rgba(251, 146, 60, 0.08);
  color: var(--exam-color);
}

/* Sidebar Footer */
.sidebar-footer {
  padding: 16px;
  border-top: 1px solid var(--border-subtle);
}

.sidebar-footer-text {
  font-size: 12px;
  color: var(--text-tertiary);
  text-align: center;
  line-height: 1.5;
}

.footer-small {
  font-size: 10px;
  opacity: 0.6;
}

/* --------------- Mobile Sidebar Toggle --------------- */
.sidebar-toggle {
  display: none;
  position: fixed;
  top: 14px;
  left: 14px;
  z-index: 200;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-medium);
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  color: var(--text-primary);
  cursor: pointer;
  align-items: center;
  justify-content: center;
}

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  z-index: 90;
}

/* --------------- Main Chat Area --------------- */
.chat-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  height: 100vh;
  min-width: 0;
  background: var(--bg-primary);
  position: relative;
}

/* Subtle gradient overlay */
.chat-main::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 300px;
  background: radial-gradient(ellipse at 50% 0%, rgba(167, 139, 250, 0.04), transparent 70%);
  pointer-events: none;
  z-index: 0;
}

/* --------------- Chat Header --------------- */
.chat-header {
  height: var(--header-height);
  padding: 0 24px;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  position: relative;
  z-index: 10;
  flex-shrink: 0;
}

.chat-header-left {
  display: flex;
  align-items: center;
  gap: 16px;
}

.chat-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
}

.chat-status {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--text-tertiary);
  font-weight: 500;
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--text-tertiary);
}

.status-dot.online {
  background: var(--nano-color);
  box-shadow: 0 0 8px var(--nano-glow);
  animation: statusPulse 2s ease-in-out infinite;
}

.status-dot.thinking {
  background: var(--cogsci-color);
  box-shadow: 0 0 8px var(--cogsci-glow);
  animation: statusPulse 0.8s ease-in-out infinite;
}

@keyframes statusPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.header-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  border: none;
  background: transparent;
  color: var(--text-tertiary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

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

/* --------------- Messages Container --------------- */
.messages-container {
  flex: 1;
  overflow-y: auto;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  position: relative;
  z-index: 1;
}

/* --------------- Welcome Screen --------------- */
.welcome-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  flex: 1;
  padding: 40px 20px;
  text-align: center;
  animation: fadeInUp 0.6s ease-out;
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.welcome-icon {
  margin-bottom: 28px;
}

.welcome-orb {
  width: 100px;
  height: 100px;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.orb-core-img {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  object-fit: cover;
  z-index: 2;
  animation: orbFloat 3s ease-in-out infinite;
  box-shadow: 0 0 20px rgba(167, 139, 250, 0.4);
}

@keyframes orbFloat {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

.orb-ring {
  position: absolute;
  border-radius: 50%;
  border: 1px solid;
  animation: orbSpin 8s linear infinite;
}

.ring-1 {
  width: 80px;
  height: 80px;
  border-color: rgba(167, 139, 250, 0.3);
  animation-duration: 8s;
}

.ring-2 {
  width: 100px;
  height: 100px;
  border-color: rgba(34, 211, 238, 0.2);
  animation-duration: 12s;
  animation-direction: reverse;
}

.ring-3 {
  width: 120px;
  height: 120px;
  border-color: rgba(52, 211, 153, 0.15);
  animation-duration: 16s;
}

@keyframes orbSpin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.welcome-title {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 8px;
}

.gradient-text {
  background: linear-gradient(135deg, var(--aiml-color), var(--bio-color), var(--nano-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.welcome-subtitle {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 40px;
  max-width: 500px;
}

.welcome-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
  max-width: 800px;
  width: 100%;
}

.welcome-card {
  background: var(--bg-glass);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 20px;
  cursor: pointer;
  transition: all var(--transition-base);
  text-align: left;
  backdrop-filter: blur(8px);
}

.welcome-card:hover {
  background: var(--bg-glass-hover);
  border-color: var(--border-medium);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.card-icon {
  font-size: 28px;
  margin-bottom: 12px;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
}

.nano-icon { background: var(--nano-bg); }
.bio-icon { background: var(--bio-bg); }
.aiml-icon { background: var(--aiml-bg); }
.cogsci-icon { background: var(--cogsci-bg); }

.welcome-card h3 {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.welcome-card p {
  font-size: 12px;
  color: var(--text-tertiary);
  line-height: 1.4;
}

.welcome-hint {
  margin-top: 32px;
  font-size: 13px;
  color: var(--text-tertiary);
  animation: fadeIn 1s ease-out 0.5s both;
}

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

/* --------------- Message Bubbles --------------- */
.message {
  display: flex;
  gap: 12px;
  padding: 12px 0;
  animation: messageSlideIn 0.3s ease-out;
  max-width: 860px;
  width: 100%;
  margin: 0 auto;
}

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

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

.message-avatar {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
  margin-top: 2px;
}

.message.assistant .message-avatar {
  background: linear-gradient(135deg, var(--aiml-color), var(--bio-color));
  box-shadow: 0 0 12px var(--accent-glow);
}

.message.user .message-avatar {
  background: var(--bg-elevated);
  border: 1px solid var(--border-medium);
}

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

.message.user .message-content {
  display: flex;
  justify-content: flex-end;
}

.message-bubble {
  border-radius: var(--radius-lg);
  padding: 12px 16px;
  font-size: 14px;
  line-height: 1.7;
  max-width: 100%;
}

.message.user .message-bubble {
  background: var(--bg-elevated);
  border: 1px solid var(--border-medium);
  color: var(--text-primary);
  max-width: 75%;
  border-bottom-right-radius: 4px;
}

.message.assistant .message-bubble {
  background: transparent;
  color: var(--text-primary);
}

/* --------------- Markdown Styles in Messages --------------- */
.message-bubble h1,
.message-bubble h2,
.message-bubble h3,
.message-bubble h4 {
  color: var(--text-primary);
  font-weight: 600;
  margin-top: 16px;
  margin-bottom: 8px;
  line-height: 1.3;
}

.message-bubble h1 { font-size: 20px; }
.message-bubble h2 { font-size: 17px; }
.message-bubble h3 { font-size: 15px; }
.message-bubble h4 { font-size: 14px; }

.message-bubble h1:first-child,
.message-bubble h2:first-child,
.message-bubble h3:first-child {
  margin-top: 0;
}

.message-bubble p {
  margin-bottom: 10px;
}

.message-bubble p:last-child {
  margin-bottom: 0;
}

.message-bubble strong {
  color: var(--text-primary);
  font-weight: 600;
}

.message-bubble em {
  color: var(--text-secondary);
  font-style: italic;
}

.message-bubble ul,
.message-bubble ol {
  margin: 8px 0;
  padding-left: 20px;
}

.message-bubble li {
  margin-bottom: 4px;
}

.message-bubble blockquote {
  border-left: 3px solid var(--accent);
  padding: 8px 16px;
  margin: 12px 0;
  background: rgba(167, 139, 250, 0.06);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-secondary);
  font-style: italic;
}

.message-bubble code {
  font-family: var(--font-mono);
  font-size: 13px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-subtle);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--aiml-color);
}

.message-bubble pre {
  margin: 12px 0;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-subtle);
}

.message-bubble pre code {
  display: block;
  padding: 16px;
  background: var(--bg-secondary);
  border: none;
  overflow-x: auto;
  line-height: 1.5;
  color: var(--text-primary);
  font-size: 13px;
}

.message-bubble table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0;
  font-size: 13px;
}

.message-bubble th,
.message-bubble td {
  padding: 8px 12px;
  text-align: left;
  border: 1px solid var(--border-subtle);
}

.message-bubble th {
  background: var(--bg-elevated);
  font-weight: 600;
  color: var(--text-primary);
}

.message-bubble td {
  color: var(--text-secondary);
}

.message-bubble a {
  color: var(--accent);
  text-decoration: none;
}

.message-bubble a:hover {
  text-decoration: underline;
}

.message-bubble hr {
  border: none;
  border-top: 1px solid var(--border-subtle);
  margin: 16px 0;
}

/* Chat Message Media */
.message-media-container {
  margin-top: 8px;
  max-width: 300px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--border-subtle);
}

.message-media-container img {
  width: 100%;
  height: auto;
  display: block;
}

.message-file-attachment {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
  background: var(--bg-primary);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-medium);
  margin-top: 8px;
}

.message-file-icon {
  font-size: 24px;
}

.message-file-name {
  font-size: 13px;
  color: var(--text-primary);
  font-weight: 500;
  word-break: break-all;
}

/* --------------- Typing Indicator --------------- */
.typing-indicator {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 8px 0;
}

.typing-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  animation: typingBounce 1.4s ease-in-out infinite;
}

.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes typingBounce {
  0%, 60%, 100% { transform: translateY(0); opacity: 0.4; }
  30% { transform: translateY(-6px); opacity: 1; }
}

/* --------------- Input Area --------------- */
.input-area {
  padding: 16px 24px 20px;
  position: relative;
  z-index: 10;
}

.input-container {
  max-width: 860px;
  margin: 0 auto;
}

/* File Preview */
.file-preview-container {
  margin-bottom: 12px;
  padding: 0 4px;
}

.file-preview {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  padding: 8px 12px;
  position: relative;
  box-shadow: var(--shadow-sm);
}

.file-preview img {
  width: 40px;
  height: 40px;
  border-radius: 4px;
  object-fit: cover;
}

.file-icon-preview {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  background: var(--bg-secondary);
  border-radius: 4px;
}

.file-details {
  display: flex;
  flex-direction: column;
  padding-right: 24px;
}

.file-name {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-primary);
  max-width: 200px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-size {
  font-size: 11px;
  color: var(--text-tertiary);
}

.remove-file-btn {
  position: absolute;
  top: -8px;
  right: -8px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-medium);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 10px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.remove-file-btn:hover {
  background: rgba(239, 68, 68, 0.2);
  color: #fca5a5;
  border-color: rgba(239, 68, 68, 0.5);
}

.input-wrapper {
  display: flex;
  align-items: flex-end;
  gap: 8px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-lg);
  padding: 8px 8px 8px 16px;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-sm);
}

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

.attach-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  border: none;
  background: transparent;
  color: var(--text-tertiary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
  margin-bottom: 2px;
}

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

.message-input {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 14px;
  line-height: 1.5;
  resize: none;
  outline: none;
  max-height: 200px;
  padding: 6px 0;
}

.message-input::placeholder {
  color: var(--text-tertiary);
}

.send-btn {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: none;
  background: var(--accent);
  color: white;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.send-btn:hover:not(:disabled) {
  background: var(--accent-hover);
  box-shadow: 0 0 16px var(--accent-glow);
  transform: scale(1.05);
}

.send-btn:active:not(:disabled) {
  transform: scale(0.95);
}

.send-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.input-footer {
  display: flex;
  justify-content: space-between;
  padding: 6px 4px 0;
}

.char-count,
.input-hint {
  font-size: 11px;
  color: var(--text-tertiary);
}

/* --------------- Error Message --------------- */
.error-bubble {
  background: rgba(239, 68, 68, 0.1) !important;
  border: 1px solid rgba(239, 68, 68, 0.2) !important;
  color: #fca5a5 !important;
}

/* --------------- Developer Badge --------------- */
.dev-badge {
  position: fixed;
  bottom: 20px;
  right: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-full);
  z-index: 1000;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-fast);
  cursor: default;
}

.dev-badge:hover {
  background: var(--bg-glass-hover);
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px var(--accent-glow);
}

.dev-badge-icon {
  font-size: 14px;
}

.dev-badge-text {
  font-size: 12px;
  color: var(--text-secondary);
}

.dev-badge-text strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* --------------- Responsive --------------- */
@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    left: 0;
    top: 0;
    transform: translateX(-100%);
    box-shadow: var(--shadow-lg);
  }

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

  .sidebar-overlay.visible {
    display: block;
  }

  .sidebar-toggle {
    display: flex;
  }

  .chat-header {
    padding-left: 60px;
  }

  .messages-container {
    padding: 16px;
  }

  .input-area {
    padding: 12px 16px 16px;
  }

  .welcome-cards {
    grid-template-columns: 1fr 1fr;
  }

  .welcome-title {
    font-size: 22px;
  }

  .message.user .message-bubble {
    max-width: 90%;
  }
}

@media (max-width: 480px) {
  .welcome-cards {
    grid-template-columns: 1fr;
  }

  .welcome-orb {
    width: 80px;
    height: 80px;
  }

  .orb-core {
    font-size: 32px;
  }

  .ring-1 { width: 65px; height: 65px; }
  .ring-2 { width: 80px; height: 80px; }
  .ring-3 { width: 95px; height: 95px; }

  .dev-badge {
    bottom: 12px;
    right: 12px;
    padding: 6px 10px;
  }
  
  .dev-badge-text {
    font-size: 10px;
  }
}