:root {
  --bg: #f7f5ef;
  --fg: #2f2a24;
  --muted: #7a6f60;
  --accent: #8b5e3c;
  --line: rgba(139, 94, 60, 0.22);
  --panel: #fffdf7;
  --chip: #8b5e3c;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.55;
}

/* Two-pane app layout */
.sd-app {
  display: grid;
  grid-template-columns: 320px 1fr;
  min-height: 100vh;
}

.sd-nav {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  border-right: 1px solid var(--line);
  background: var(--panel);
  padding: 1.4rem 1.2rem 2rem;
}

.sd-nav-head {
  margin-bottom: 1rem;
}

.sd-title {
  font-size: 1.25rem;
  line-height: 1.2;
  margin: 0 0 0.2rem;
  color: var(--accent);
}

.sd-lead {
  font-size: 0.85rem;
  color: var(--muted);
  margin: 0;
}

.sd-searchbar {
  display: flex;
  gap: 0.4rem;
  margin-bottom: 0.9rem;
}

.sd-input {
  flex: 1;
  padding: 0.55rem 0.75rem;
  font-size: 0.95rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
  color: var(--fg);
  min-width: 0;
}

.sd-input:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.sd-button {
  padding: 0.55rem 0.9rem;
  font-size: 0.95rem;
  border: 1px solid var(--accent);
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  white-space: nowrap;
}

.sd-button:hover {
  filter: brightness(1.08);
}

.sd-nav-section {
  margin-bottom: 1.1rem;
}

.sd-nav-h {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  border-bottom: 1px solid var(--line);
  padding-bottom: 0.25rem;
  margin: 0 0 0.55rem;
}

/* Compact category list in the nav */
.sd-category-list {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.sd-category-card {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
  padding: 0.45rem 0.7rem;
  cursor: pointer;
  transition: border-color 0.15s ease;
}

.sd-category-card:hover {
  border-color: var(--accent);
}

.sd-category-name {
  font-weight: 600;
  color: var(--accent);
}

.sd-category-count {
  font-size: 0.72rem;
  color: var(--muted);
  white-space: nowrap;
}

/* Main pane */
.sd-main {
  padding: 1.6rem 2rem 3rem;
  min-width: 0;
}

.sd-pane h2 {
  font-size: 1.3rem;
  color: var(--accent);
  border-bottom: 1px solid var(--line);
  padding-bottom: 0.35rem;
  margin: 0 0 0.9rem;
}

.sd-welcome p {
  color: var(--muted);
  max-width: 46rem;
}

/* Breadcrumb navigation */
.sd-breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.25rem;
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
}

.sd-crumb .sd-rel-word {
  color: var(--accent);
  font-weight: 500;
}

.sd-crumb .sd-rel-link {
  cursor: pointer;
}

.sd-crumb .sd-rel-link:hover .sd-rel-word {
  text-decoration: underline;
}

.sd-crumb-sep {
  color: var(--muted);
  margin: 0 0.15rem;
}

.sd-crumb-current {
  font-weight: 600;
}

.sd-hint {
  margin: 0 0 0.75rem;
  font-size: 0.85rem;
  color: var(--muted);
}

.sd-id-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.82rem;
  color: var(--muted);
  cursor: pointer;
  user-select: none;
  margin-top: 0.5rem;
}

.sd-id-toggle input {
  accent-color: var(--accent);
}

/* Identifiers hidden by default */
.sd-rel-id,
.sd-concept-id,
.sd-result-id {
  display: none;
}

body.sd-ids-on .sd-rel-id,
body.sd-ids-on .sd-concept-id,
body.sd-ids-on .sd-result-id {
  display: inline;
}

.sd-results {
  display: grid;
  gap: 0.6rem;
}

.sd-result {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  padding: 0.7rem 0.9rem;
  cursor: pointer;
}

.sd-result:hover {
  border-color: var(--accent);
}

.sd-result-head {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.sd-result-term {
  font-weight: 600;
}

.sd-tag {
  font-size: 0.72rem;
  padding: 0.1em 0.5em;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--muted);
  white-space: nowrap;
}

.sd-tag--preferred { border-color: var(--accent); color: var(--accent); }
.sd-tag--deprecated { text-decoration: line-through; }

.sd-result-def {
  margin: 0.35rem 0 0;
  font-size: 0.92rem;
  color: var(--muted);
}

.sd-card {
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
  padding: 1.1rem 1.2rem;
}

.sd-card-head {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  flex-wrap: wrap;
  margin-bottom: 0.7rem;
}

.sd-concept-id {
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: 0.8rem;
  color: var(--muted);
}

.sd-definition {
  margin: 0 0 1rem;
}

.sd-block {
  margin-bottom: 1rem;
}

.sd-block h3 {
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
  margin: 0 0 0.4rem;
}

/* Collapsible relation group */
.sd-collapse {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
  padding: 0.4rem 0.7rem;
  margin-bottom: 0.5rem;
}

.sd-collapse summary {
  cursor: pointer;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--accent);
  list-style: none;
  user-select: none;
}

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

.sd-collapse summary::before {
  content: "▸ ";
  display: inline-block;
  transition: transform 0.12s ease;
}

.sd-collapse[open] summary::before {
  transform: rotate(90deg);
}

.sd-collapse .sd-relations {
  margin-top: 0.4rem;
}

/* Browse drill-down node */
.sd-browse-node {
  cursor: pointer;
}

.sd-browse-node .sd-rel-word {
  color: var(--accent);
  font-weight: 600;
}

.sd-browse-node:hover .sd-rel-word {
  text-decoration: underline;
}

.sd-terms {
  list-style: none;
  padding: 0;
  margin: 0;
}

.sd-terms li {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  padding: 0.15rem 0;
}

.sd-relations {
  list-style: none;
  padding: 0;
  margin: 0;
}

.sd-relations li {
  padding: 0.2rem 0;
  border-bottom: 1px dashed rgba(139, 94, 60, 0.12);
}

.sd-relation-type {
  display: inline-block;
  min-width: 8.5em;
  font-size: 0.78rem;
  color: var(--muted);
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
}

.sd-rel-link {
  color: var(--accent);
  text-decoration: none;
  cursor: pointer;
}

.sd-rel-link:hover {
  text-decoration: underline;
}

.sd-rel-word {
  font-weight: 600;
  color: var(--fg);
}

.sd-rel-id {
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: 0.72rem;
  color: var(--muted);
}

.sd-rel-def {
  color: var(--muted);
  font-size: 0.85rem;
}

.sd-source {
  font-size: 0.82rem;
  color: var(--muted);
  margin-top: 0.4rem;
}

/* Collapsible hierarchy tree */
.sd-tree-root,
.sd-tree-children {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

.sd-tree-children {
  padding-left: 0.9rem;
}

.sd-tree-item {
  padding: 0.1rem 0;
}

.sd-tree-line {
  display: flex;
  align-items: baseline;
  gap: 0.15rem;
}

.sd-tree-toggle {
  display: inline-block;
  width: 1em;
  text-align: center;
  color: var(--accent);
  cursor: pointer;
  user-select: none;
  font-size: 0.8rem;
}

.sd-tree-node {
  cursor: pointer;
  font-size: 0.9rem;
}

.sd-tree-node .sd-rel-word {
  color: var(--accent);
  font-weight: 500;
}

.sd-tree-node:hover .sd-rel-word {
  text-decoration: underline;
}

.sd-tree-item .sd-tree-children .sd-tree-node .sd-rel-word {
  font-weight: 400;
}

.sd-nested-children {
  padding-left: 1rem;
}

.sd-empty {
  color: var(--muted);
  font-size: 0.85rem;
  padding: 0.2rem 0;
}

/* Import panel */
.sd-import {
  border: 1px dashed var(--line);
  border-radius: 10px;
  padding: 0.5rem 1rem 1rem;
  margin-top: 1.5rem;
}

.sd-import-actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.75rem;
  flex-wrap: wrap;
}

.sd-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.4rem;
}

.sd-chip {
  display: inline-flex;
  align-items: center;
  padding: 0.4rem 0.8rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--fg);
  text-decoration: none;
  font-size: 0.85rem;
  cursor: pointer;
}

.sd-chip:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.sd-chip--danger {
  border-color: rgba(180, 60, 60, 0.4);
  color: #a04444;
}

.sd-chip--danger:hover {
  border-color: #b03a3a;
  color: #b03a3a;
}

.sd-about p {
  margin: 0 0 0.8rem;
  max-width: 46rem;
}

/* Mobile: single column, nav on top */
@media (max-width: 860px) {
  .sd-app {
    grid-template-columns: 1fr;
  }

  .sd-nav {
    position: static;
    height: auto;
    overflow: visible;
    border-right: none;
    border-bottom: 1px solid var(--line);
    padding: 1rem;
  }

  .sd-main {
    padding: 1.2rem 1rem 2.5rem;
  }
}