:root {
  --bg: #f6f7f4;
  --sidebar: #eef1ec;
  --panel: #ffffff;
  --ink: #1f2722;
  --muted: #68736d;
  --line: #d9e0d8;
  --accent: #1f6f5b;
  --accent-soft: #e0eee9;
  --warn: #a95f23;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--bg);
  font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
}

button,
input,
textarea {
  font: inherit;
}

button {
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--ink);
  border-radius: 6px;
  padding: 8px 10px;
  cursor: pointer;
}

button:hover {
  border-color: var(--accent);
}

button:active {
  transform: translateY(1px);
}

.app-shell {
  display: grid;
  grid-template-columns: 292px minmax(420px, 1fr) 320px;
  height: 100vh;
  min-height: 720px;
}

.sidebar {
  display: grid;
  grid-template-rows: auto auto auto auto minmax(0, 1fr) auto;
  gap: 10px;
  padding: 14px;
  background: var(--sidebar);
  border-right: 1px solid var(--line);
  min-width: 0;
}

.brand p,
.eyebrow {
  margin: 0 0 4px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
}

.brand h1,
.chat-header h2,
.trace-head h2,
h3,
p {
  margin: 0;
}

.brand h1 {
  font-size: 20px;
}

.new-chat-button {
  width: 100%;
  color: #fff;
  background: var(--accent);
  border-color: var(--accent);
  font-weight: 700;
}

.sidebar-search {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 9px 10px;
  outline: none;
  background: #fff;
}

.sidebar-notice {
  border: 1px solid rgba(31, 111, 91, 0.18);
  border-radius: 8px;
  padding: 9px 10px;
  color: var(--accent);
  background: rgba(31, 111, 91, 0.08);
  font-size: 13px;
  line-height: 1.45;
}

.sidebar-search:focus,
.composer textarea:focus,
.session-title-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(31, 111, 91, 0.12);
}

.sidebar-section {
  min-height: 0;
}

.session-section {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
}

.docs-section {
  border-top: 1px solid var(--line);
  padding-top: 12px;
}

.sidebar-section-head,
.trace-head,
.chat-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.sidebar-section-head {
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 13px;
}

.sidebar-section-head button {
  padding: 5px 8px;
  font-size: 12px;
}

.session-list {
  min-height: 0;
  overflow-y: auto;
  padding-right: 2px;
}

.session-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 4px;
  margin-bottom: 3px;
  border-radius: 8px;
}

.session-item {
  min-width: 0;
  text-align: left;
  border: 1px solid transparent;
  background: transparent;
  padding: 9px 8px;
  border-radius: 8px;
}

.session-row:hover,
.session-row.active {
  background: var(--accent-soft);
}

.session-row.active .session-item {
  border-color: transparent;
}

.session-title {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-weight: 700;
}

.session-meta {
  display: block;
  overflow: hidden;
  color: var(--muted);
  font-size: 12px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.session-actions {
  display: flex;
  align-items: center;
  gap: 4px;
  padding-right: 4px;
}

.session-more {
  width: 28px;
  height: 28px;
  padding: 0;
  color: var(--muted);
  background: transparent;
  border-color: transparent;
  opacity: 0;
}

.session-delete {
  min-width: 28px;
  height: 28px;
  padding: 0 6px;
  color: var(--muted);
  background: transparent;
  border-color: transparent;
  opacity: 0;
  font-size: 12px;
}

.session-row:hover .session-more,
.session-row.active .session-more,
.session-more:focus,
.session-row:hover .session-delete,
.session-row.active .session-delete,
.session-delete:focus {
  opacity: 1;
}

.session-more:hover,
.session-delete:hover {
  background: #fff;
}

.session-row.editing {
  grid-template-columns: 1fr;
  padding: 8px;
  background: var(--accent-soft);
}

.session-title-input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 7px;
  padding: 8px 9px;
  outline: none;
}

.session-edit-actions {
  display: flex;
  gap: 6px;
  margin-top: 7px;
}

.session-edit-actions button {
  flex: 1;
  padding: 6px 8px;
  font-size: 12px;
}

.sidebar-empty {
  display: grid;
  gap: 4px;
  padding: 12px 9px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}

.sidebar-empty strong {
  color: var(--ink);
  font-size: 14px;
}

.upload-button {
  display: block;
  width: 100%;
  padding: 9px 10px;
  border: 1px dashed var(--accent);
  border-radius: 6px;
  color: var(--accent);
  text-align: center;
  cursor: pointer;
  background: rgba(31, 111, 91, 0.07);
}

.upload-button input {
  display: none;
}

.doc-list {
  max-height: 180px;
  overflow-y: auto;
  margin-top: 8px;
}

.trace-item {
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 9px;
  margin-bottom: 8px;
  background: #fff;
}

.trace-item strong {
  display: block;
  margin-bottom: 4px;
}

.trace-item span,
.trace-item code {
  color: var(--muted);
  font-size: 12px;
  overflow-wrap: anywhere;
}

.file-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: start;
  gap: 6px;
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 4px;
  margin-bottom: 6px;
}

.file-item:hover,
.file-item.active {
  border-color: var(--line);
  background: #fff;
}

.file-open {
  min-width: 0;
  border-color: transparent;
  background: transparent;
  padding: 6px;
  text-align: left;
}

.file-open strong,
.document-preview-head strong,
.chunk-card strong {
  display: block;
}

.file-open span,
.document-preview-head span {
  display: block;
  margin-top: 3px;
  color: var(--muted);
  font-size: 12px;
}

.file-delete {
  margin-top: 2px;
  padding: 5px 8px;
  font-size: 12px;
}

.main-column {
  display: grid;
  grid-template-rows: auto auto minmax(0, 1fr) auto;
  min-width: 0;
  background: #fbfcfa;
}

.chat-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--line);
}

.chat-header h2 {
  font-size: 22px;
}

.chat-header span {
  color: var(--muted);
  font-size: 13px;
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--warn);
}

.dot.ok {
  background: var(--accent);
}

.quick-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  padding: 12px 20px;
  border-bottom: 1px solid var(--line);
}

.messages {
  padding: 20px;
  overflow-y: auto;
}

.message {
  max-width: 76%;
  margin-bottom: 12px;
  padding: 12px 14px;
  border-radius: 8px;
  line-height: 1.55;
  white-space: pre-wrap;
}

.message.user {
  margin-left: auto;
  color: #fff;
  background: var(--accent);
}

.message.assistant {
  background: #fff;
  border: 1px solid var(--line);
}

.composer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  padding: 16px 20px;
  border-top: 1px solid var(--line);
}

.composer textarea {
  width: 100%;
  resize: none;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 12px;
  outline: none;
}

.composer button {
  min-width: 76px;
  color: #fff;
  background: var(--accent);
  border-color: var(--accent);
}

.trace-panel {
  overflow-y: auto;
  background: #f7f9f6;
  border-left: 1px solid var(--line);
}

.trace-head {
  padding: 16px;
  border-bottom: 1px solid var(--line);
}

.trace-head h2 {
  font-size: 18px;
}

.trace-head span {
  color: var(--muted);
  font-size: 13px;
}

.trace-block {
  padding: 16px;
  border-bottom: 1px solid var(--line);
}

.trace-block h3 {
  font-size: 14px;
  margin-bottom: 10px;
}

.trace-list.empty {
  color: var(--muted);
  font-size: 14px;
}

.trace-item.handoff {
  border-color: rgba(169, 95, 35, 0.45);
  background: #fff7ed;
}

.trace-item.handoff strong {
  color: var(--warn);
}

.document-preview {
  display: grid;
  gap: 10px;
}

.document-preview-head {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px;
  background: #fff;
}

.chunk-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px;
  background: #fff;
}

.chunk-card strong {
  margin-bottom: 6px;
  color: var(--accent);
  font-size: 12px;
}

.chunk-card p {
  color: var(--ink);
  font-size: 13px;
  line-height: 1.6;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.document-page {
  min-height: 100vh;
  background:
    radial-gradient(circle at 16% 0%, rgba(31, 111, 91, 0.12), transparent 26%),
    linear-gradient(135deg, #f8faf7 0%, #eef3ee 100%);
}

.document-shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 48px;
}

.document-hero {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 24px;
  background: rgba(255, 255, 255, 0.78);
  box-shadow: 0 18px 60px rgba(31, 39, 34, 0.08);
}

.back-link {
  display: inline-flex;
  margin-bottom: 18px;
  color: var(--accent);
  font-weight: 700;
  text-decoration: none;
}

.back-link:hover {
  text-decoration: underline;
}

.document-hero h1 {
  max-width: 900px;
  margin: 4px 0 8px;
  font-size: clamp(28px, 5vw, 52px);
  line-height: 1.08;
  overflow-wrap: anywhere;
}

.document-hero p:last-child {
  color: var(--muted);
}

.document-layout {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 18px;
  margin-top: 18px;
}

.document-toc,
.document-content {
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.78);
}

.document-toc {
  position: sticky;
  top: 18px;
  align-self: start;
  padding: 16px;
}

.document-toc h2 {
  margin: 0 0 12px;
  font-size: 15px;
}

.chunk-toc-list {
  display: grid;
  gap: 6px;
}

.chunk-toc-list a {
  border-radius: 8px;
  padding: 8px 9px;
  color: var(--muted);
  text-decoration: none;
}

.chunk-toc-list a:hover {
  color: var(--accent);
  background: var(--accent-soft);
}

.document-content {
  padding: 18px;
}

.document-status {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 14px;
  color: var(--muted);
  background: #fff;
}

.document-status.error {
  color: var(--warn);
  border-color: rgba(169, 95, 35, 0.42);
  background: #fff7ed;
}

.document-chunks {
  display: grid;
  gap: 14px;
}

.document-chunk-card {
  scroll-margin-top: 18px;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px;
  background: #fff;
}

.document-chunk-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
  color: var(--muted);
  font-size: 13px;
}

.document-chunk-head strong {
  color: var(--accent);
}

.document-chunk-card p {
  color: var(--ink);
  line-height: 1.75;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

@media (max-width: 1100px) {
  .app-shell {
    grid-template-columns: 260px minmax(360px, 1fr);
  }

  .trace-panel {
    display: none;
  }
}

@media (max-width: 720px) {
  .app-shell {
    grid-template-columns: 1fr;
    height: auto;
  }

  .sidebar {
    min-height: 360px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .message {
    max-width: 100%;
  }

  .composer {
    grid-template-columns: 1fr;
  }

  .document-layout {
    grid-template-columns: 1fr;
  }

  .document-toc {
    position: static;
  }
}