:root {
  --bg: #faf9f5;
  --panel: #ffffff;
  --border: #e5e2da;
  --text: #1f1d18;
  --muted: #6b6862;
  --accent: #2a5dbb;
  --accent-hover: #224e9d;
  --danger: #b34a3a;
  --success: #2f7a4f;
  --code-bg: #f1ede4;
  --shadow: 0 1px 2px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.04);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 14px;
  line-height: 1.5;
  color: var(--text);
  background: var(--bg);
}

code {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.92em;
  background: var(--code-bg);
  padding: 1px 5px;
  border-radius: 3px;
}

/* ─── Top bar ─────────────────────────────────────────── */
.topbar {
  display: flex;
  align-items: center;
  gap: 32px;
  padding: 12px 24px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 16px;
}
.brand-icon { font-size: 22px; }

.tabs {
  display: flex;
  gap: 4px;
  flex: 1;
}
.tab {
  background: transparent;
  border: 0;
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 14px;
  color: var(--muted);
  cursor: pointer;
  font-weight: 500;
}
.tab:hover { background: var(--code-bg); color: var(--text); }
.tab.active {
  background: var(--text);
  color: var(--panel);
}
.badge {
  display: inline-block;
  margin-left: 6px;
  padding: 1px 8px;
  border-radius: 10px;
  background: rgba(255,255,255,0.2);
  font-size: 11px;
  font-weight: 600;
}
.tab:not(.active) .badge {
  background: var(--code-bg);
  color: var(--muted);
}

.user {
  color: var(--muted);
  font-size: 13px;
}

/* ─── Panels ───────────────────────────────────────────── */
main {
  padding: 24px;
  max-width: 1400px;
  margin: 0 auto;
}
.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ─── Browse tab ───────────────────────────────────────── */
section[data-panel="browse"] {
  display: none;
  grid-template-columns: 320px 1fr;
  gap: 24px;
  align-items: start;
}
section[data-panel="browse"].active { display: grid; }

.kb-tree {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  position: sticky;
  top: 80px;
  max-height: calc(100vh - 120px);
  overflow: auto;
  box-shadow: var(--shadow);
}
.tree-header {
  display: flex;
  gap: 6px;
  margin-bottom: 10px;
}
.tree-header input {
  flex: 1;
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 13px;
}
.icon-btn {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  font-size: 14px;
  padding: 6px 10px;
}
.tree-root ul {
  list-style: none;
  padding-left: 12px;
  margin: 0;
}
.tree-root > ul {
  padding-left: 0;
}
.tree-dir {
  font-weight: 600;
  color: var(--text);
  padding: 2px 0;
  cursor: pointer;
  user-select: none;
}
.tree-file {
  padding: 3px 6px;
  border-radius: 4px;
  cursor: pointer;
  color: var(--muted);
  font-size: 13px;
}
.tree-file:hover {
  background: var(--code-bg);
  color: var(--text);
}
.tree-file.active {
  background: var(--accent);
  color: var(--panel);
}
.tree-collapsed { display: none; }

.kb-view {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 24px 32px;
  min-height: 60vh;
  box-shadow: var(--shadow);
}
.placeholder {
  color: var(--muted);
  padding: 40px 0;
}
.placeholder h2 { color: var(--text); margin-top: 0; }

.kb-view-header {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}
.kb-view-header h2 { margin: 0 0 4px; }
.kb-view-meta {
  display: flex;
  gap: 12px;
  font-size: 12px;
  color: var(--muted);
}
.kb-view-tabs {
  display: flex;
  gap: 4px;
  margin-bottom: 12px;
}
.view-tab {
  background: transparent;
  border: 1px solid transparent;
  padding: 4px 12px;
  border-radius: 6px;
  cursor: pointer;
  color: var(--muted);
  font-size: 13px;
}
.view-tab.active {
  border-color: var(--border);
  color: var(--text);
  background: var(--code-bg);
}
.view-pane { display: none; }
.view-pane.active { display: block; }

.markdown-body { padding-top: 8px; }
.markdown-body h1, .markdown-body h2, .markdown-body h3 { margin-top: 1.4em; }
.markdown-body h1:first-child, .markdown-body h2:first-child { margin-top: 0; }
.markdown-body pre {
  background: var(--code-bg);
  padding: 12px 16px;
  border-radius: 6px;
  overflow: auto;
}
.markdown-body table {
  border-collapse: collapse;
  margin: 8px 0;
}
.markdown-body th, .markdown-body td {
  border: 1px solid var(--border);
  padding: 6px 12px;
  text-align: left;
}
.source-pane {
  background: var(--code-bg);
  padding: 16px;
  border-radius: 6px;
  white-space: pre-wrap;
  word-break: break-word;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 12.5px;
  line-height: 1.5;
}

/* ─── Edit pane ────────────────────────────────────────── */
.edit-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}
.edit-header h2 { margin: 0; }
#edit-source {
  width: 100%;
  min-height: 60vh;
  padding: 12px 16px;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.5;
  border: 1px solid var(--border);
  border-radius: 6px;
  resize: vertical;
  background: #fcfbf7;
}
.edit-footer {
  display: flex;
  gap: 12px;
  margin-top: 12px;
}
#edit-summary {
  flex: 1;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 14px;
}
.edit-status {
  margin-top: 16px;
  padding: 12px;
  border-radius: 6px;
}
.edit-status.success { background: #e8f5ee; color: var(--success); }
.edit-status.error { background: #fcebe7; color: var(--danger); }

/* ─── Missing tab ──────────────────────────────────────── */
.missing-header {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 20px 24px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
}
.missing-header h2 { margin: 0 0 6px; }
.muted { color: var(--muted); font-size: 13px; margin: 0 0 12px; }
.filter-row {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 13px;
}
.filter-row label { user-select: none; }

.missing-list { display: flex; flex-direction: column; gap: 8px; }
.missing-item {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 20px;
  box-shadow: var(--shadow);
}
.missing-question { font-size: 15px; margin: 0 0 6px; }
.missing-meta {
  display: flex;
  gap: 16px;
  color: var(--muted);
  font-size: 12px;
  margin-bottom: 10px;
}
.missing-actions { display: flex; gap: 8px; }
.kind-issue { color: var(--danger); font-weight: 600; }

/* ─── Buttons ──────────────────────────────────────────── */
.btn {
  background: var(--panel);
  border: 1px solid var(--border);
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  color: var(--text);
}
.btn:hover { background: var(--code-bg); }
.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: white;
}
.btn.primary:hover { background: var(--accent-hover); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* ─── Review tab ───────────────────────────────────────── */
section[data-panel="review"] {
  display: none;
  grid-template-columns: 320px 1fr;
  gap: 24px;
  align-items: start;
}
section[data-panel="review"].active { display: grid; }

.review-list {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  position: sticky;
  top: 80px;
  max-height: calc(100vh - 120px);
  overflow: auto;
  box-shadow: var(--shadow);
}
.review-list-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}
.review-items { display: flex; flex-direction: column; gap: 6px; }
.review-item {
  padding: 10px 12px;
  border-radius: 6px;
  cursor: pointer;
  border: 1px solid transparent;
}
.review-item:hover { background: var(--code-bg); }
.review-item.active {
  background: var(--code-bg);
  border-color: var(--accent);
}
.review-item-title {
  font-weight: 500;
  margin-bottom: 4px;
  font-size: 13px;
  line-height: 1.35;
}
.review-item-meta {
  font-size: 11px;
  color: var(--muted);
  display: flex;
  gap: 8px;
}

.review-view {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 24px 32px;
  min-height: 60vh;
  box-shadow: var(--shadow);
}
.review-header { margin-bottom: 16px; padding-bottom: 16px; border-bottom: 1px solid var(--border); }
.review-header h2 { margin: 0 0 6px; }
.review-meta {
  display: flex;
  gap: 16px;
  font-size: 12px;
  color: var(--muted);
  align-items: center;
}
.muted-link { color: var(--muted); font-size: 12px; }

.review-files { display: flex; flex-direction: column; gap: 24px; margin-bottom: 24px; }
.review-file {
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
}
.review-file-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 14px;
  background: var(--code-bg);
  border-bottom: 1px solid var(--border);
  font-size: 13px;
}
.review-file-header code { background: transparent; padding: 0; font-weight: 500; }
.review-file-status {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  padding: 2px 8px;
  border-radius: 999px;
}
.status-added { background: #ddf4e2; color: var(--success); }
.status-modified { background: #fff0d6; color: #8a6500; }
.status-removed { background: #fcebe7; color: var(--danger); }
.review-diff-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  background: var(--bg);
}
.review-pane {
  padding: 12px 16px;
  font-size: 12.5px;
  line-height: 1.5;
  background: var(--panel);
  border-right: 1px solid var(--border);
  max-height: 60vh;
  overflow: auto;
}
.review-pane:last-child { border-right: none; }
.review-pane-label {
  font-size: 11px;
  font-weight: 600;
  color: var(--muted);
  margin-bottom: 6px;
  text-transform: uppercase;
}
.review-pane-source {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  white-space: pre-wrap;
  word-break: break-word;
}
.review-pane.removed { background: #fdf2f0; }
.review-pane.added { background: #f3faf5; }
.review-empty { color: var(--muted); font-style: italic; }
.review-toggle {
  display: flex;
  gap: 4px;
  padding: 8px 14px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
}
.review-toggle button {
  background: transparent;
  border: 0;
  font-size: 11.5px;
  padding: 4px 10px;
  border-radius: 4px;
  cursor: pointer;
  color: var(--muted);
}
.review-toggle button.active {
  background: var(--text);
  color: var(--panel);
}

.review-comments { border-top: 1px solid var(--border); padding-top: 16px; margin-bottom: 24px; }
.review-comments h3 { margin: 0 0 10px; font-size: 14px; }
.comments-list { display: flex; flex-direction: column; gap: 8px; margin-bottom: 10px; }
.comment-item {
  background: var(--code-bg);
  border-radius: 6px;
  padding: 8px 12px;
  font-size: 13px;
}
.comment-author { font-weight: 600; font-size: 12px; }
.comment-meta { color: var(--muted); font-size: 11px; }
#review-comment-box {
  width: 100%;
  min-height: 80px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 13px;
  font-family: inherit;
  resize: vertical;
}

.review-actions {
  display: flex;
  gap: 8px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  align-items: center;
}

/* ─── Proposals tab ────────────────────────────────────── */
.proposals-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.proposal-item {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  box-shadow: var(--shadow);
}
.proposal-state {
  font-size: 11px;
  font-weight: 600;
  padding: 2px 10px;
  border-radius: 999px;
  text-transform: uppercase;
}
.state-open { background: #ddf4e2; color: var(--success); }
.state-merged { background: #e9deff; color: #5a30a7; }
.state-closed { background: var(--code-bg); color: var(--muted); }