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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: 15px;
  line-height: 1.6;
  color: #1a1a1a;
  background: #f7f7f5;
  min-height: 100vh;
}

/* ── Header ── */
header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  max-width: 860px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem 1rem;
  border-bottom: 2px solid #ddd;
  margin-bottom: 1.5rem;
}

header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  color: #1a1a1a;
}

.source-link {
  font-size: 0.8rem;
  color: #888;
  text-decoration: none;
}

.source-link:hover {
  color: #0645ad;
  text-decoration: underline;
}

/* ── Loading ── */
#loading {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  padding: 4rem 1rem;
  color: #888;
  font-size: 0.95rem;
}

#loading.hidden {
  display: none;
}

.spinner {
  width: 1.25rem;
  height: 1.25rem;
  border: 2px solid #ddd;
  border-top-color: #666;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  flex-shrink: 0;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ── Error ── */
.error-message {
  max-width: 860px;
  margin: 2rem auto;
  padding: 1rem 1.25rem;
  background: #fff3f3;
  border: 1px solid #fcc;
  border-radius: 6px;
  color: #c00;
  font-size: 0.9rem;
}

/* ── Main app container ── */
#app {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 1.25rem 3rem;
}

/* ── Day block ── */
.day-block {
  margin-bottom: 2rem;
}

.day-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0 0.4rem;
  border-bottom: 2px solid #ccc;
  margin-bottom: 0.75rem;
  cursor: pointer;
  user-select: none;
}

.day-header:hover {
  border-bottom-color: #999;
}

.day-header .toggle-btn {
  font-size: 0.65rem;
  color: #999;
  flex-shrink: 0;
  transition: color 0.15s;
}

.day-header:hover .toggle-btn {
  color: #555;
}

.day-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: #222;
}

.day-body {
  overflow: hidden;
  max-height: 9999px;
  opacity: 1;
  transition: max-height 0.25s ease-out, opacity 0.2s ease-out;
}

.day-block[data-collapsed="true"] .day-body {
  max-height: 0;
  opacity: 0;
}

/* ── Category ── */
.category-block {
  margin-bottom: 0.25rem;
}

.category-header {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.5rem 0 0.2rem;
  cursor: pointer;
  user-select: none;
}

.category-header .toggle-btn {
  font-size: 0.6rem;
  color: #aaa;
  flex-shrink: 0;
  transition: color 0.15s;
}

.category-header:hover .toggle-btn {
  color: #666;
}

.category-title {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: #777;
}

.category-body {
  overflow: hidden;
  max-height: 9999px;
  opacity: 1;
  transition: max-height 0.25s ease-out, opacity 0.2s ease-out;
  padding-left: 0.25rem;
}

.category-block[data-collapsed="true"] .category-body {
  max-height: 0;
  opacity: 0;
}

/* ── Tree nodes (list items) ── */
.tree-node {
  margin: 0.15rem 0;
}

.tree-node-header {
  display: flex;
  align-items: baseline;
  gap: 0.4rem;
  padding: 0.1rem 0;
}

.tree-node-header .toggle-btn {
  font-size: 0.55rem;
  color: #bbb;
  flex-shrink: 0;
  cursor: pointer;
  user-select: none;
  margin-top: 0.15rem;
  transition: color 0.15s;
  line-height: 1.6;
}

.tree-node-header:hover > .toggle-btn {
  color: #666;
}

/* Spacer to align leaf nodes with toggle nodes */
.toggle-spacer {
  display: inline-block;
  width: 0.95rem;
  flex-shrink: 0;
}

.tree-node-label {
  font-size: 0.92rem;
  color: #2a2a2a;
  line-height: 1.55;
}

.tree-node-label a {
  color: #0645ad;
  text-decoration: none;
}

.tree-node-label a:hover {
  text-decoration: underline;
}

/* Suppress any residual Wikipedia list styling in label HTML */
.tree-node-label ul,
.tree-node-label li {
  list-style: none;
  padding: 0;
  margin: 0;
}

.tree-node-children {
  border-left: 2px solid #e8e8e8;
  margin-left: 0.35rem;
  padding-left: 0.85rem;
  overflow: hidden;
  max-height: 9999px;
  opacity: 1;
  transition: max-height 0.2s ease-out, opacity 0.18s ease-out;
}

.tree-node[data-collapsed="true"] > .tree-node-children {
  max-height: 0;
  opacity: 0;
}

/* Slightly mute deeper nesting levels */
.tree-node-children .tree-node-label {
  color: #3a3a3a;
}

.tree-node-children .tree-node-children .tree-node-label {
  color: #555;
  font-size: 0.88rem;
}

.tree-node-children .tree-node-children .tree-node-children .tree-node-label {
  color: #666;
  font-size: 0.85rem;
}