/* ── Internal Explorer ────────────────────────────────────────────────────── */

.site-main:has(.explorer-split) {
  max-width: min(92rem, 100%);
  padding: 0;
}

.explorer-split {
  display: grid;
  grid-template-columns: minmax(18rem, 24rem) minmax(0, 1fr);
  min-height: calc(100vh - 5rem);
  border: 1px solid var(--c-border);
  border-radius: var(--r-xl);
  overflow: hidden;
  background: var(--c-bg-card);
  box-shadow: var(--c-shadow-lg);
}

.explorer-sidebar {
  display: flex;
  flex-direction: column;
  min-width: 0;
  border-right: 1px solid var(--c-border);
  background:
    linear-gradient(180deg, color-mix(in srgb, var(--c-accent-subtle) 65%, var(--c-bg-card)) 0%, var(--c-bg-card) 100%);
}

.sidebar-header {
  padding: var(--sp-lg);
  border-bottom: 1px solid var(--c-border);
}

.sidebar-header h1 {
  margin: 0;
  font-size: var(--fs-xl);
  letter-spacing: -0.03em;
}

.sidebar-header p {
  margin-top: var(--sp-xs);
  color: var(--c-text-secondary);
  font-size: var(--fs-sm);
}

.explorer-tree {
  flex: 1;
  overflow: auto;
  padding: var(--sp-sm);
}

.explorer-content {
  min-width: 0;
  overflow: auto;
  padding: var(--sp-2xl);
  background:
    radial-gradient(circle at top left, color-mix(in srgb, var(--c-accent-subtle) 40%, transparent) 0%, transparent 28%),
    var(--c-bg-card);
}

.explorer-welcome,
.explorer-loading,
.explorer-error,
.explorer-empty {
  min-height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--sp-md);
  text-align: center;
  color: var(--c-text-secondary);
}

.welcome-icon,
.explorer-loading span {
  font-size: 2.5rem;
}

.explorer-tree ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.explorer-tree ul ul {
  margin-left: 0.85rem;
  padding-left: 0.85rem;
  border-left: 1px solid var(--c-border-light);
}

.explorer-folder,
.explorer-file {
  display: flex;
  align-items: center;
  gap: var(--sp-sm);
  width: 100%;
  padding: 0.45rem 0.6rem;
  border-radius: var(--r-md);
  color: var(--c-text);
  text-decoration: none;
  transition: background var(--tr-fast), color var(--tr-fast);
}

.explorer-folder {
  cursor: pointer;
  user-select: none;
  font-weight: 600;
}

.explorer-folder:hover,
.explorer-file:hover,
.explorer-file.active {
  background: var(--c-accent-subtle);
  color: var(--c-accent);
}

.explorer-folder::before {
  content: "▶";
  flex: 0 0 0.75rem;
  font-size: 0.7rem;
  color: var(--c-text-muted);
  transition: transform var(--tr-fast);
}

.explorer-folder[aria-expanded="true"]::before {
  transform: rotate(90deg);
}

.folder-name,
.file-title {
  min-width: 0;
  flex: 1;
}

.folder-count,
.file-date {
  flex: 0 0 auto;
  font-size: var(--fs-xs);
  color: var(--c-text-muted);
}

.folder-count {
  padding: 0.1rem 0.45rem;
  border-radius: var(--r-full);
  background: var(--c-bg-code);
}

.explorer-children {
  display: none;
}

.explorer-children.open {
  display: block;
}

@media (max-width: 900px) {
  .explorer-split {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .explorer-sidebar {
    border-right: 0;
    border-bottom: 1px solid var(--c-border);
  }

  .explorer-content {
    padding: var(--sp-lg);
    min-height: 50vh;
  }
}