    :root {
      {{THEME_VARS}}
      --body-bg: {{BODY_BG}};
      --container-bg: {{CONTAINER_BG}};
      --info-bg: {{INFO_BG}};
    }

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

    :root {
      --line-height: 18px; /* 12px font * 1.5 */
      --sidebar-width: 400px;
      --sidebar-min-width: 240px;
      --sidebar-max-width: 840px;
      --sidebar-resizer-width: 6px;
    }

    body {
      font-family: ui-monospace, 'Cascadia Code', 'Source Code Pro', Menlo, Consolas, 'DejaVu Sans Mono', monospace;
      font-size: 12px;
      line-height: var(--line-height);
      color: var(--text);
      background: var(--body-bg);
    }

    body.sidebar-resizing {
      cursor: col-resize;
      user-select: none;
    }

    #app {
      display: flex;
      min-height: 100vh;
    }

    /* Sidebar */
    #sidebar {
      width: var(--sidebar-width);
      min-width: var(--sidebar-width);
      max-width: var(--sidebar-width);
      background: var(--container-bg);
      flex-shrink: 0;
      display: flex;
      flex-direction: column;
      position: sticky;
      top: 0;
      height: 100vh;
      border-right: 1px solid var(--dim);
    }

    #sidebar-resizer {
      width: var(--sidebar-resizer-width);
      flex-shrink: 0;
      position: sticky;
      top: 0;
      height: 100vh;
      cursor: col-resize;
      touch-action: none;
      background: transparent;
      border-right: 1px solid transparent;
    }

    #sidebar-resizer:hover,
    body.sidebar-resizing #sidebar-resizer {
      background: var(--selectedBg);
      border-right-color: var(--dim);
    }

    .sidebar-header {
      padding: 8px 12px;
      flex-shrink: 0;
    }

    .sidebar-controls {
      padding: 8px 8px 4px 8px;
    }

    .sidebar-search {
      width: 100%;
      box-sizing: border-box;
      padding: 4px 8px;
      font-size: 11px;
      font-family: inherit;
      background: var(--body-bg);
      color: var(--text);
      border: 1px solid var(--dim);
      border-radius: 3px;
    }

    .sidebar-filters {
      display: flex;
      padding: 4px 8px 8px 8px;
      gap: 4px;
      align-items: center;
      flex-wrap: wrap;
    }

    .sidebar-search:focus {
      outline: none;
      border-color: var(--accent);
    }

    .sidebar-search::placeholder {
      color: var(--muted);
    }

    .filter-btn {
      padding: 3px 8px;
      font-size: 10px;
      font-family: inherit;
      background: transparent;
      color: var(--muted);
      border: 1px solid var(--dim);
      border-radius: 3px;
      cursor: pointer;
    }

    .filter-btn:hover {
      color: var(--text);
      border-color: var(--text);
    }

    .filter-btn.active {
      background: var(--accent);
      color: var(--body-bg);
      border-color: var(--accent);
    }

    .sidebar-close {
      display: none;
      padding: 3px 8px;
      font-size: 12px;
      font-family: inherit;
      background: transparent;
      color: var(--muted);
      border: 1px solid var(--dim);
      border-radius: 3px;
      cursor: pointer;
      margin-left: auto;
    }

    .sidebar-close:hover {
      color: var(--text);
      border-color: var(--text);
    }

    .tree-container {
      flex: 1;
      overflow: auto;
      padding: 4px 0;
    }

    .tree-node {
      padding: 0 8px;
      cursor: pointer;
      display: flex;
      align-items: baseline;
      font-size: 11px;
      line-height: 13px;
      white-space: nowrap;
    }

    .tree-node:hover {
      background: var(--selectedBg);
    }

    .tree-node.active {
      background: var(--selectedBg);
    }

    .tree-node.active .tree-content {
      font-weight: bold;
    }

    .tree-node.in-path {
      background: color-mix(in srgb, var(--accent) 10%, transparent);
    }

    .tree-node:not(.in-path) {
      opacity: 0.5;
    }

    .tree-node:not(.in-path):hover {
      opacity: 1;
    }

    .tree-prefix {
      color: var(--muted);
      flex-shrink: 0;
      font-family: monospace;
      white-space: pre;
    }

    .tree-marker {
      color: var(--accent);
      flex-shrink: 0;
    }

    .tree-content {
      color: var(--text);
    }

    .tree-role-user {
      color: var(--accent);
    }

    .tree-role-skill {
      color: var(--customMessageLabel);
    }

    .tree-role-assistant {
      color: var(--success);
    }

    .tree-role-tool {
      color: var(--muted);
    }

    .tree-muted {
      color: var(--muted);
    }

    .tree-error {
      color: var(--error);
    }

    .tree-compaction {
      color: var(--borderAccent);
    }

    .tree-branch-summary {
      color: var(--warning);
    }

    .tree-custom-message {
      color: var(--customMessageLabel);
    }

    .tree-status {
      padding: 4px 12px;
      font-size: 10px;
      color: var(--muted);
      flex-shrink: 0;
    }

    /* Main content */
    #content {
      flex: 1;
      min-width: 0;
      overflow-y: auto;
      padding: var(--line-height) calc(var(--line-height) * 2);
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    #content > * {
      width: 100%;
      max-width: 800px;
    }

    /* Help bar */
    .help-bar {
      font-size: 11px;
      color: var(--warning);
      margin-bottom: var(--line-height);
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 12px;
    }

    .help-hint {
      flex: 1 1 240px;
    }

    .help-actions {
      display: flex;
      align-items: center;
      flex-wrap: wrap;
      gap: 8px;
    }

    .header-toggle-btn,
    .download-json-btn {
      font-size: 10px;
      padding: 2px 8px;
      background: var(--container-bg);
      border: 1px solid var(--border);
      border-radius: 3px;
      color: var(--text);
      cursor: pointer;
      font-family: inherit;
    }

    .header-toggle-btn:hover,
    .download-json-btn:hover {
      background: var(--hover);
      border-color: var(--borderAccent);
    }

    /* Header */
    .header {
      background: var(--container-bg);
      border-radius: 4px;
      padding: var(--line-height);
      margin-bottom: var(--line-height);
    }

    .header h1 {
      font-size: 12px;
      font-weight: bold;
      color: var(--borderAccent);
      margin-bottom: var(--line-height);
    }

    .header-info {
      display: flex;
      flex-direction: column;
      gap: 0;
      font-size: 11px;
    }

    .info-item {
      color: var(--dim);
      display: flex;
      align-items: baseline;
    }

    .info-label {
      font-weight: 600;
      margin-right: 8px;
      min-width: 100px;
    }

    .info-value {
      color: var(--text);
      flex: 1;
    }

    /* Messages */
    #messages {
      display: flex;
      flex-direction: column;
      gap: var(--line-height);
    }

    .message-timestamp {
      font-size: 10px;
      color: var(--dim);
      opacity: 0.8;
    }

    .user-message {
      background: var(--userMessageBg);
      color: var(--userMessageText);
      padding: var(--line-height);
      border-radius: 4px;
      position: relative;
    }

    .assistant-message {
      padding: 0;
      position: relative;
    }

    /* Copy link button - appears on hover */
    .copy-link-btn {
      position: absolute;
      top: 8px;
      right: 8px;
      width: 28px;
      height: 28px;
      padding: 6px;
      background: var(--container-bg);
      border: 1px solid var(--dim);
      border-radius: 4px;
      color: var(--muted);
      cursor: pointer;
      opacity: 0;
      transition: opacity 0.15s, background 0.15s, color 0.15s;
      display: flex;
      align-items: center;
      justify-content: center;
      z-index: 10;
    }

    .user-message:hover .copy-link-btn,
    .assistant-message:hover .copy-link-btn,
    .skill-user-entry:hover .copy-link-btn {
      opacity: 1;
    }

    .copy-link-btn:hover {
      background: var(--accent);
      color: var(--body-bg);
      border-color: var(--accent);
    }

    .copy-link-btn.copied {
      background: var(--success, #22c55e);
      color: white;
      border-color: var(--success, #22c55e);
    }

    /* Highlight effect for deep-linked messages */
    .user-message.highlight,
    .assistant-message.highlight {
      animation: highlight-pulse 2s ease-out;
    }

    @keyframes highlight-pulse {
      0% {
        box-shadow: 0 0 0 3px var(--accent);
      }
      100% {
        box-shadow: 0 0 0 0 transparent;
      }
    }

    .assistant-message > .message-timestamp {
      padding-left: var(--line-height);
    }

    .assistant-text {
      padding: var(--line-height);
      padding-bottom: 0;
    }

    .message-timestamp + .assistant-text,
    .message-timestamp + .thinking-block {
      padding-top: 0;
    }

    .thinking-block + .assistant-text {
      padding-top: 0;
    }

    .thinking-text {
      padding: var(--line-height);
      color: var(--thinkingText);
      font-style: italic;
      white-space: pre-wrap;
    }

    .message-timestamp + .thinking-block .thinking-text,
    .message-timestamp + .thinking-block .thinking-collapsed {
      padding-top: 0;
    }

    .thinking-collapsed {
      display: none;
      padding: var(--line-height);
      color: var(--thinkingText);
      font-style: italic;
    }

    /* Tool execution */
    .tool-execution {
      padding: var(--line-height);
      border-radius: 4px;
      cursor: pointer;
    }

    .tool-execution + .tool-execution {
      margin-top: var(--line-height);
    }

    .assistant-text + .tool-execution {
      margin-top: var(--line-height);
    }

    .tool-execution.pending { background: var(--toolPendingBg); }
    .tool-execution.success { background: var(--toolSuccessBg); }
    .tool-execution.error { background: var(--toolErrorBg); }

    .tool-execution.collapsed > *:not(.tool-header):not(.tool-command):not(.message-timestamp) {
      display: none;
    }

    .tool-execution > .tool-header,
    .tool-execution > .tool-command {
      position: relative;
      padding-right: 1.4em;
    }

    .tool-execution > .tool-header::after,
    .tool-execution > .tool-command::after {
      content: '\25BE';
      position: absolute;
      right: 0;
      top: 0;
      color: var(--dim);
      font-weight: normal;
      transition: transform 0.15s ease;
    }

    .tool-execution.collapsed > .tool-header::after,
    .tool-execution.collapsed > .tool-command::after {
      transform: rotate(-90deg);
    }

    .tool-header, .tool-name {
      font-weight: bold;
    }

    .tool-path {
      color: var(--accent);
      word-break: break-all;
    }

    .line-numbers {
      color: var(--warning);
    }

    .line-count {
      color: var(--dim);
    }

    .tool-command {
      font-weight: bold;
      white-space: pre-wrap;
      word-wrap: break-word;
      overflow-wrap: break-word;
      word-break: break-word;
    }

    .tool-output {
      margin-top: var(--line-height);
      color: var(--toolOutput);
      word-wrap: break-word;
      overflow-wrap: break-word;
      word-break: break-word;
      font-family: inherit;
      overflow-x: auto;
    }

    .tool-output > div,
    .output-preview > div,
    .output-full > div {
      margin: 0;
      padding: 0;
      line-height: var(--line-height);
    }

    .tool-output > div:not(.output-preview):not(.output-full),
    .output-preview > div:not(.expand-hint),
    .output-full > div:not(.expand-hint) {
      white-space: pre-wrap;
    }

    .tool-output pre {
      margin: 0;
      padding: 0;
      font-family: inherit;
      color: inherit;
      white-space: pre-wrap;
      word-wrap: break-word;
      overflow-wrap: break-word;
    }

    .tool-output code {
      padding: 0;
      background: none;
      color: var(--text);
    }

    .tool-output.expandable {
      cursor: pointer;
    }

    .tool-output.expandable:hover {
      opacity: 0.9;
    }

    .tool-output.expandable .output-full {
      display: none;
    }

    .tool-output.expandable.expanded .output-preview {
      display: none;
    }

    .tool-output.expandable.expanded .output-full {
      display: block;
    }

    .ansi-line {
      white-space: pre;
    }

    .tool-images {
    }

    .tool-image {
      max-width: 100%;
      max-height: 500px;
      border-radius: 4px;
      margin: var(--line-height) 0;
    }

    .expand-hint {
      color: var(--toolOutput);
    }

    /* Diff */
    .tool-diff {
      font-size: 11px;
      overflow-x: auto;
      white-space: pre;
    }

    .diff-added { color: var(--toolDiffAdded); }
    .diff-removed { color: var(--toolDiffRemoved); }
    .diff-context { color: var(--toolDiffContext); }

    /* Model change */
    .model-change {
      padding: 0 var(--line-height);
      color: var(--dim);
      font-size: 11px;
    }

    .model-name {
      color: var(--borderAccent);
      font-weight: bold;
    }

    /* Compaction / Branch Summary - matches customMessage colors from TUI */
    .compaction {
      background: var(--customMessageBg);
      border-radius: 4px;
      padding: var(--line-height);
      cursor: pointer;
    }

    .compaction-label {
      color: var(--customMessageLabel);
      font-weight: bold;
    }

    .compaction-collapsed {
      color: var(--customMessageText);
    }

    .compaction-content {
      display: none;
      color: var(--customMessageText);
      white-space: pre-wrap;
      margin-top: var(--line-height);
    }

    .compaction.expanded .compaction-collapsed {
      display: none;
    }

    .compaction.expanded .compaction-content {
      display: block;
    }

    /* System prompt */
    .system-prompt {
      background: var(--customMessageBg);
      padding: var(--line-height);
      border-radius: 4px;
      margin-bottom: var(--line-height);
    }

    .system-prompt.expandable {
      cursor: pointer;
    }

    .system-prompt-header {
      font-weight: bold;
      color: var(--customMessageLabel);
    }

    .system-prompt-preview {
      color: var(--customMessageText);
      white-space: pre-wrap;
      word-wrap: break-word;
      font-size: 11px;
      margin-top: var(--line-height);
    }

    .system-prompt-expand-hint {
      color: var(--muted);
      font-style: italic;
      margin-top: 4px;
    }

    .system-prompt-full {
      display: none;
      color: var(--customMessageText);
      white-space: pre-wrap;
      word-wrap: break-word;
      font-size: 11px;
      margin-top: var(--line-height);
    }

    .system-prompt.expanded .system-prompt-preview,
    .system-prompt.expanded .system-prompt-expand-hint {
      display: none;
    }

    .system-prompt.expanded .system-prompt-full {
      display: block;
    }

    .system-prompt.provider-prompt {
      border-left: 3px solid var(--warning);
    }

    .system-prompt-note {
      font-size: 10px;
      font-style: italic;
      color: var(--muted);
      margin-top: 4px;
    }

    /* Tools list */
    .tools-list {
      background: var(--customMessageBg);
      padding: var(--line-height);
      border-radius: 4px;
      margin-bottom: var(--line-height);
    }

    .tools-header {
      font-weight: bold;
      color: var(--customMessageLabel);
      margin-bottom: var(--line-height);
    }

    .tool-item {
      font-size: 11px;
    }

    .tool-item-name {
      font-weight: bold;
      color: var(--text);
    }

    .tool-item-desc {
      color: var(--dim);
    }

    .tool-params-hint {
      color: var(--muted);
      font-style: italic;
    }

    .tool-item:has(.tool-params-hint) {
      cursor: pointer;
    }

    .tool-params-hint::after {
      content: '[click to show parameters]';
    }

    .tool-item.params-expanded .tool-params-hint::after {
      content: '[hide parameters]';
    }

    .tool-params-content {
      display: none;
      margin-top: 4px;
      margin-left: 12px;
      padding-left: 8px;
      border-left: 1px solid var(--dim);
    }

    .tool-item.params-expanded .tool-params-content {
      display: block;
    }

    .tool-param {
      margin-bottom: 4px;
      font-size: 11px;
    }

    .tool-param-name {
      font-weight: bold;
      color: var(--text);
    }

    .tool-param-type {
      color: var(--dim);
      font-style: italic;
    }

    .tool-param-required {
      color: var(--warning, #e8a838);
      font-size: 10px;
    }

    .tool-param-optional {
      color: var(--dim);
      font-size: 10px;
    }

    .tool-param-desc {
      color: var(--dim);
      margin-left: 8px;
    }

    /* Hook/custom messages */
    .hook-message {
      background: var(--customMessageBg);
      color: var(--customMessageText);
      padding: var(--line-height);
      border-radius: 4px;
    }

    .hook-type {
      color: var(--customMessageLabel);
      font-weight: bold;
    }

    /* Skill invocation - matches compaction style (clickable, collapsed by default) */
    .skill-invocation {
      background: var(--customMessageBg);
      border-radius: 4px;
      padding: var(--line-height);
      cursor: pointer;
    }

    .skill-invocation-label {
      color: var(--customMessageLabel);
      font-weight: bold;
    }

    .skill-invocation-collapsed {
      color: var(--customMessageText);
    }

    .skill-invocation-content {
      display: none;
      color: var(--customMessageText);
      margin-top: var(--line-height);
    }

    .skill-invocation.expanded .skill-invocation-collapsed {
      display: none;
    }

    .skill-invocation.expanded .skill-invocation-content {
      display: block;
    }

    .skill-invocation + .user-message {
      margin-top: var(--line-height);
    }

    .skill-user-entry {
      position: relative;
    }

    /* Branch summary */
    .branch-summary {
      background: var(--customMessageBg);
      padding: var(--line-height);
      border-radius: 4px;
    }

    .branch-summary-header {
      font-weight: bold;
      color: var(--borderAccent);
    }

    /* Error */
    .error-text {
      color: var(--error);
      padding: 0 var(--line-height);
    }
    .tool-error {
      color: var(--error);
    }

    /* Images */
    .message-images {
      margin-bottom: 12px;
    }

    .message-image {
      max-width: 100%;
      max-height: 400px;
      border-radius: 4px;
      margin: var(--line-height) 0;
    }

    /* Markdown content */
    .markdown-content h1,
    .markdown-content h2,
    .markdown-content h3,
    .markdown-content h4,
    .markdown-content h5,
    .markdown-content h6 {
      color: var(--mdHeading);
      margin: var(--line-height) 0 0 0;
      font-weight: bold;
    }

    .markdown-content h1 { font-size: 1em; }
    .markdown-content h2 { font-size: 1em; }
    .markdown-content h3 { font-size: 1em; }
    .markdown-content h4 { font-size: 1em; }
    .markdown-content h5 { font-size: 1em; }
    .markdown-content h6 { font-size: 1em; }
    .markdown-content p { margin: 0; }
    .markdown-content p + p { margin-top: var(--line-height); }

    .markdown-content a {
      color: var(--mdLink);
      text-decoration: underline;
    }

    .markdown-content code {
      background: rgba(128, 128, 128, 0.2);
      color: var(--mdCode);
      padding: 0 4px;
      border-radius: 3px;
      font-family: inherit;
    }

    .markdown-content pre {
      background: transparent;
      margin: var(--line-height) 0;
      overflow-x: auto;
    }

    .markdown-content pre code {
      display: block;
      background: none;
      color: var(--text);
    }

    .markdown-content blockquote {
      border-left: 3px solid var(--mdQuoteBorder);
      padding-left: var(--line-height);
      margin: var(--line-height) 0;
      color: var(--mdQuote);
      font-style: italic;
    }

    .markdown-content ul,
    .markdown-content ol {
      margin: var(--line-height) 0;
      padding-left: calc(var(--line-height) * 2);
    }

    .markdown-content li { margin: 0; }
    .markdown-content li::marker { color: var(--mdListBullet); }

    .markdown-content hr {
      border: none;
      border-top: 1px solid var(--mdHr);
      margin: var(--line-height) 0;
    }

    .markdown-content table {
      border-collapse: collapse;
      margin: 0.5em 0;
      width: 100%;
    }

    .markdown-content th,
    .markdown-content td {
      border: 1px solid var(--mdCodeBlockBorder);
      padding: 6px 10px;
      text-align: left;
    }

    .markdown-content th {
      background: rgba(128, 128, 128, 0.1);
      font-weight: bold;
    }

    .markdown-content img {
      max-width: 100%;
      border-radius: 4px;
    }

    /* Syntax highlighting */
    .hljs { background: transparent; color: var(--text); }
    .hljs-comment, .hljs-quote { color: var(--syntaxComment); }
    .hljs-keyword, .hljs-selector-tag { color: var(--syntaxKeyword); }
    .hljs-number, .hljs-literal { color: var(--syntaxNumber); }
    .hljs-string, .hljs-doctag { color: var(--syntaxString); }
    /* Function names: hljs v11 uses .hljs-title.function_ compound class */
    .hljs-function, .hljs-title, .hljs-title.function_, .hljs-section, .hljs-name { color: var(--syntaxFunction); }
    /* Types: hljs v11 uses .hljs-title.class_ for class names */
    .hljs-type, .hljs-class, .hljs-title.class_, .hljs-built_in { color: var(--syntaxType); }
    .hljs-attr, .hljs-variable, .hljs-variable.language_, .hljs-params, .hljs-property { color: var(--syntaxVariable); }
    .hljs-meta, .hljs-meta .hljs-keyword, .hljs-meta .hljs-string { color: var(--syntaxKeyword); }
    .hljs-operator { color: var(--syntaxOperator); }
    .hljs-punctuation { color: var(--syntaxPunctuation); }
    .hljs-subst { color: var(--text); }

    /* Footer */
    .footer {
      margin-top: 48px;
      padding: 20px;
      text-align: center;
      color: var(--dim);
      font-size: 10px;
    }

    /* Mobile */
    #hamburger {
      display: none;
      position: fixed;
      top: 10px;
      left: 10px;
      z-index: 100;
      padding: 3px 8px;
      font-size: 12px;
      font-family: inherit;
      background: transparent;
      color: var(--muted);
      border: 1px solid var(--dim);
      border-radius: 3px;
      cursor: pointer;
    }

    #hamburger:hover {
      color: var(--text);
      border-color: var(--text);
    }



    #sidebar-overlay {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      background: rgba(0, 0, 0, 0.5);
      z-index: 98;
    }

    @media (max-width: 900px) {
      #sidebar {
        position: fixed;
        left: 0;
        width: min(var(--sidebar-width), 100vw);
        min-width: min(var(--sidebar-width), 100vw);
        max-width: min(var(--sidebar-width), 100vw);
        top: 0;
        bottom: 0;
        height: 100vh;
        z-index: 99;
        transform: translateX(-100%);
        transition: transform 0.3s;
      }

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

      #sidebar-resizer {
        display: none;
      }

      #sidebar-overlay.open {
        display: block;
      }

      #hamburger {
        display: block;
      }

      .sidebar-close {
        display: block;
      }

      #content {
        padding: var(--line-height) 16px;
      }

      #content > * {
        max-width: 100%;
      }
    }

    @media print {
      #sidebar, #sidebar-resizer, #sidebar-toggle { display: none !important; }
      body { background: white; color: black; }
      #content { max-width: none; }
    }

    /* Embedded in site iframe (?embed=1) */
    body[data-embed="1"] #sidebar,
    body[data-embed="1"] #sidebar-resizer,
    body[data-embed="1"] #hamburger,
    body[data-embed="1"] #sidebar-overlay {
      display: none !important;
    }

    body[data-embed="1"] #app {
      display: block;
    }

    body[data-embed="1"] #content {
      flex: 1;
      max-width: none;
    }
