web/app.css

/* Minimalist Control-LLM Stylesheet with Streaming, Font Scaling, KaTeX & Dual Themes */

:root {
  /* Dark Theme (Default) */
  --bg-app: #0f1217;
  --bg-sidebar: #13171f;
  --bg-nav: #141820;
  --bg-card: #181d26;
  --bg-input: #1a202c;
  --bg-hover: #222936;
  
  --border-color: #28303f;
  --border-focus: #3b82f6;
  
  --text-main: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-accent: #60a5fa;
  --text-danger: #f87171;
  
  --chat-font-size: 15px;
  
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', SFMono-Regular, monospace;
}

[data-theme="light"] {
  --bg-app: #f8fafc;
  --bg-sidebar: #f1f5f9;
  --bg-nav: #ffffff;
  --bg-card: #ffffff;
  --bg-input: #f1f5f9;
  --bg-hover: #e2e8f0;
  
  --border-color: #e2e8f0;
  --border-focus: #2563eb;
  
  --text-main: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --text-accent: #2563eb;
  --text-danger: #dc2626;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-app);
  color: var(--text-main);
  line-height: 1.6;
  height: 100vh;
  overflow: hidden;
  transition: background-color 0.2s ease, color 0.2s ease;
}

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

/* Sidebar */
.sidebar {
  width: 260px;
  background-color: var(--bg-sidebar);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  transition: width 0.25s ease, padding 0.25s ease;
  overflow: hidden;
  z-index: 20;
}

.sidebar.collapsed {
  width: 0;
  border-right: none;
}

.sidebar-header {
  padding: 14px 16px;
  border-bottom: 1px solid var(--border-color);
}

.btn-new-chat {
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 0.15s ease;
}

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

.sidebar-history {
  flex: 1;
  overflow-y: auto;
  padding: 14px 10px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.history-label {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  padding: 4px 8px;
  margin-bottom: 4px;
}

.history-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.history-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 10px;
  border-radius: 6px;
  font-size: 13px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.12s ease;
  user-select: none;
}

.history-item:hover {
  background: var(--bg-hover);
  color: var(--text-main);
}

.history-item.active {
  background: var(--bg-card);
  color: var(--text-main);
  font-weight: 500;
  border: 1px solid var(--border-color);
}

.history-item-title {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.btn-delete-chat {
  display: none;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 2px;
  font-size: 12px;
}

.history-item:hover .btn-delete-chat {
  display: block;
}

.btn-delete-chat:hover {
  color: var(--text-danger);
}

/* Sidebar Footer */
.sidebar-footer {
  padding: 12px 16px;
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.sidebar-footer-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: 6px 8px;
  border-radius: 6px;
  font-size: 12px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 0.15s ease;
  text-align: left;
}

.sidebar-footer-btn:hover {
  background: var(--bg-hover);
  color: var(--text-main);
}

/* Main Content Area */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  height: 100vh;
}

/* Navbar */
.navbar {
  height: 52px;
  background-color: var(--bg-nav);
  border-bottom: 1px solid var(--border-color);
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-shrink: 0;
}

.navbar-left, .navbar-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-title {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text-main);
}

.btn-nav-icon {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 6px;
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s ease;
}

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

[data-theme="dark"] .sun-icon { display: block; }
[data-theme="dark"] .moon-icon { display: none; }
[data-theme="light"] .sun-icon { display: none; }
[data-theme="light"] .moon-icon { display: block; }

/* Scrollable Chat Viewport - Full width so scrollbar is on the far right edge */
.chat-viewport {
  flex: 1;
  width: 100%;
  min-height: 0;
  overflow-y: auto;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  scroll-behavior: smooth;
}

/* Chat Thread - Centered clean 920px canvas */
.chat-thread {
  flex: 1;
  width: 100%;
  max-width: 920px;
  margin: 0 auto;
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  gap: 28px;
}

/* Bottom Input Area */
.input-container {
  width: 100%;
  flex-shrink: 0;
  background: var(--bg-main);
  border-top: 1px solid var(--border-color);
}

/* Hero Welcome Screen */
.hero-container {
  margin: auto 0;
  text-align: center;
  padding: 20px 0;
}

.hero-title {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 4px;
}

.hero-subtitle {
  color: var(--text-muted);
  font-size: 12px;
  font-family: var(--font-mono);
  margin-bottom: 28px;
}

.preset-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  text-align: left;
}

.preset-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 14px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.preset-card:hover {
  border-color: var(--text-accent);
  background: var(--bg-hover);
  transform: translateY(-1px);
}

.preset-heading {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 4px;
}

.preset-detail {
  font-size: 12px;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* Message Entries - Modern Embedded Seamless Design */
.message-entry {
  display: flex;
  flex-direction: column;
  gap: 8px;
  animation: fadeIn 0.18s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(3px); }
  to { opacity: 1; transform: translateY(0); }
}

.message-label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.03em;
  display: flex;
  align-items: center;
  gap: 6px;
}

.message-entry.user .message-label {
  color: var(--text-secondary);
}

.message-entry.bot .message-label {
  color: var(--text-main);
}

/* User Message: Soft Elevated Pill */
.message-entry.user .message-content {
  background: var(--bg-hover);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 14px 18px;
  font-size: var(--chat-font-size);
  line-height: 1.6;
  color: var(--text-main);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

/* Bot Message: Embedded Directly (No Card Box) */
.message-entry.bot .message-content {
  background: transparent;
  border: none;
  border-radius: 0;
  padding: 2px 0 8px 0;
  font-size: var(--chat-font-size);
  line-height: 1.7;
  color: var(--text-main);
}

/* LaTeX & KaTeX Enhancements */
.katex-display {
  margin: 12px 0 !important;
  overflow-x: auto;
  overflow-y: hidden;
  padding: 4px 0;
}

.katex {
  font-size: 1.05em !important;
}

/* Markdown formatting */
.message-content h1, .message-content h2, .message-content h3 {
  margin-top: 14px;
  margin-bottom: 8px;
  font-size: 1.1em;
  font-weight: 600;
}

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

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

.message-content ul, .message-content ol {
  margin-left: 20px;
  margin-bottom: 10px;
}

.message-content code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--bg-hover);
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

/* Code Blocks with Syntax Highlighting & Header */
.code-block-wrapper {
  margin: 14px 0;
  background: #181825;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.code-block-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 14px;
  background: rgba(255, 255, 255, 0.04);
  border-bottom: 1px solid var(--border-color);
}

.code-lang-label {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  text-transform: uppercase;
}

.btn-copy-code {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 11px;
  padding: 3px 8px;
  border-radius: 4px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  transition: all 0.15s ease;
}

.btn-copy-code:hover {
  background: var(--bg-hover);
  color: var(--text-main);
  border-color: var(--text-accent);
}

.code-block-wrapper pre {
  margin: 0 !important;
  padding: 14px 16px !important;
  background: transparent !important;
  border: none !important;
  border-radius: 0 !important;
  overflow-x: auto;
}

.code-block-wrapper pre code {
  font-family: 'JetBrains Mono', 'Menlo', monospace !important;
  font-size: calc(var(--chat-font-size) * 0.87) !important;
  line-height: 1.6 !important;
  background: transparent !important;
  padding: 0 !important;
  border: none !important;
  display: block;
}

.hljs {
  background: transparent !important;
}

/* Thinking Process Accordion - Minimal & Modern */
.thought-accordion {
  margin-bottom: 14px;
  background: var(--bg-hover);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  display: block !important;
  width: fit-content;
  max-width: 100%;
  clear: both;
}

.response-body {
  display: block;
  width: 100%;
  clear: both;
}

.generating-indicator {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 12px;
}

.generating-indicator .dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: currentColor;
  animation: generating-pulse 1.1s ease-in-out infinite;
}

.generating-indicator .dot:nth-child(2) { animation-delay: 0.15s; }
.generating-indicator .dot:nth-child(3) { animation-delay: 0.3s; }

@keyframes generating-pulse {
  0%, 60%, 100% { opacity: 0.25; transform: translateY(0); }
  30% { opacity: 1; transform: translateY(-2px); }
}

.thought-summary {
  padding: 6px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  user-select: none;
  background: transparent;
  transition: color 0.15s ease;
}

.thought-summary:hover {
  color: var(--text-main);
}

.thought-summary svg {
  transition: transform 0.2s ease;
}

.thought-accordion[open] .thought-summary svg {
  transform: rotate(90deg);
}

.thought-summary::-webkit-details-marker {
  display: none;
}

.thought-content {
  padding: 10px 14px;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: calc(var(--chat-font-size) * 0.73);
  line-height: 1.6;
  border-top: 1px solid var(--border-color);
  white-space: pre-wrap;
  max-height: 240px;
  overflow-y: auto;
}

/* Tool Execution Card - Subtle Embedded Badge */
.tool-summary-card {
  margin-top: 12px;
  padding: 8px 12px;
  background: var(--bg-hover);
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--text-accent);
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-secondary);
  display: inline-block;
  max-width: 100%;
}

/* Plot Card - Clean Embedded Container */
.plot-container {
  margin-top: 14px;
  background: var(--bg-hover);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 12px;
}

.plot-image {
  max-width: 100%;
  border-radius: 6px;
  display: block;
}

.plot-caption {
  font-family: var(--font-mono);
  font-size: calc(var(--chat-font-size) * 0.73);
  color: var(--text-muted);
  margin-top: 6px;
}

/* Input Area - Centered 920px */
.input-wrapper {
  max-width: 920px;
  width: 100%;
  margin: 0 auto;
  padding: 12px 24px 20px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
  box-sizing: border-box;
}

/* Math Helper Toolbar */
.math-toolbar {
  display: flex;
  align-items: center;
  gap: 5px;
  overflow-x: auto;
  padding-bottom: 2px;
  scrollbar-width: thin;
}

.math-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 11px;
  padding: 4px 8px;
  border-radius: 5px;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.12s ease;
}

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

/* Attachment Preview */
.attachment-preview {
  display: flex;
  align-items: center;
}

.attachment-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-left: 3px solid var(--text-accent);
  padding: 4px 8px;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-main);
}

.btn-remove-attachment {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 14px;
  line-height: 1;
}

.btn-remove-attachment:hover {
  color: var(--text-danger);
}

.chat-input-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 8px 12px;
  display: flex;
  align-items: flex-end;
  gap: 8px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
  transition: border-color 0.15s ease;
}

.chat-input-box:focus-within {
  border-color: var(--border-focus);
}

.btn-attach {
  background: transparent;
  border: none;
  color: var(--text-muted);
  width: 32px;
  height: 32px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  flex-shrink: 0;
  transition: color 0.15s ease, background-color 0.15s ease;
}

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

.chat-input-box textarea {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 14px;
  resize: none;
  min-height: 24px;
  max-height: 160px;
  outline: none;
  line-height: 1.5;
  padding: 4px 0;
}

.btn-send {
  background: var(--text-accent);
  border: none;
  color: #ffffff;
  width: 32px;
  height: 32px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  flex-shrink: 0;
  transition: opacity 0.15s ease;
}

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

.footer-note {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--text-muted);
  text-align: center;
  margin-top: 4px;
}

/* Modal */
.modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(2px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.modal-backdrop.active {
  display: flex;
}

.modal-content {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  width: 520px;
  max-width: 90vw;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.3);
}

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

.modal-header h3 {
  font-size: 15px;
  font-weight: 600;
}

.btn-close {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 20px;
  cursor: pointer;
}

.modal-body {
  padding: 20px;
}

.modal-desc {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.modal-drop-zone {
  border: 2px dashed var(--border-color);
  border-radius: 6px;
  padding: 28px 16px;
  text-align: center;
  cursor: pointer;
  transition: all 0.15s ease;
}

.modal-drop-zone:hover, .modal-drop-zone.dragover {
  border-color: var(--text-accent);
  background: var(--bg-hover);
}

.drop-text {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-main);
}

.drop-sub {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
}

.modal-upload-status {
  font-family: var(--font-mono);
  font-size: 11px;
  margin-top: 12px;
  text-align: center;
}

/* Font Size Selector */
.font-size-options {
  display: flex;
  gap: 8px;
  margin-top: 8px;
}

.btn-font-size {
  flex: 1;
  background: var(--bg-app);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 12px;
  cursor: pointer;
  transition: all 0.12s ease;
}

.btn-font-size:hover {
  background: var(--bg-hover);
  color: var(--text-main);
}

.btn-font-size.active {
  border-color: var(--text-accent);
  background: var(--bg-card);
  color: var(--text-accent);
  font-weight: 600;
}

/* Quick Guide & Settings */
.guide-section {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.guide-title, .settings-title {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-main);
}

.guide-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 12px;
  color: var(--text-secondary);
}

.guide-list li code {
  font-family: var(--font-mono);
  background: var(--bg-app);
  padding: 2px 4px;
  border-radius: 3px;
  border: 1px solid var(--border-color);
}

.settings-divider {
  height: 1px;
  background: var(--border-color);
  margin: 18px 0;
}

.settings-desc {
  font-size: 12px;
  color: var(--text-muted);
  margin: 4px 0 12px;
}

.btn-danger {
  background: transparent;
  border: 1px solid var(--text-danger);
  color: var(--text-danger);
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-danger:hover {
  background: var(--text-danger);
  color: #ffffff;
}

/* Streaming Blinking Cursor */
.streaming-cursor {
  display: inline-block;
  width: 7px;
  height: 14px;
  background-color: var(--text-accent);
  margin-left: 3px;
  vertical-align: middle;
  animation: blink 0.8s infinite;
}

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