:root {
  --bg: #ffffff;
  --bg-alt: #f6f7f9;
  --border: #e2e4e8;
  --text: #1a1d21;
  --text-muted: #6b7280;
  --brand: #2563eb;
  --brand-hover: #1d4ed8;
  --danger: #dc2626;
  --success: #16a34a;
  --code-bg: #f3f4f6;
  --shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --bg-alt: #1b1e24;
    --border: #2a2e35;
    --text: #e7e9ec;
    --text-muted: #9aa1ab;
    --brand: #5b8def;
    --brand-hover: #7ba3f2;
    --danger: #f87171;
    --success: #4ade80;
    --code-bg: #1f232b;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
  }
}

* { box-sizing: border-box; }

/* .modal(display:flex) や .btn(display:inline-block) がブラウザ標準の [hidden]{display:none} より
   詳細度/優先順位で勝ってしまい、JSでhidden属性を切り替えても表示が変わらないバグへの対策。
   hidden属性は常に最優先で非表示にする。 */
[hidden] { display: none !important; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Yu Gothic", sans-serif;
  background: var(--bg);
  color: var(--text);
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.topbar {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-alt);
  flex-shrink: 0;
}
.topbar__brand { display: flex; align-items: center; gap: 8px; }
.topbar__logo { font-size: 22px; }
.topbar__title { font-weight: 600; font-size: 14px; }
.topbar__subtitle { font-size: 11px; color: var(--text-muted); }
.topbar__search { flex: 1; max-width: 420px; }
.topbar__search input {
  width: 100%;
  padding: 7px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--text);
  font-size: 13px;
}
.topbar__auth { display: flex; align-items: center; gap: 8px; margin-left: auto; }
.auth-status { font-size: 12px; color: var(--text-muted); }

.btn {
  padding: 6px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 12px;
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
}
.btn:hover { border-color: var(--brand); }
.btn--primary { background: var(--brand); border-color: var(--brand); color: #fff; }
.btn--primary:hover { background: var(--brand-hover); border-color: var(--brand-hover); }
.btn--ghost { background: transparent; }

.layout { flex: 1; display: flex; min-height: 0; }

.sidebar {
  width: 300px;
  flex-shrink: 0;
  overflow-y: auto;
  border-right: 1px solid var(--border);
  background: var(--bg-alt);
  padding: 10px;
  font-size: 13px;
}
.sidebar__loading { color: var(--text-muted); padding: 8px; }

.sidebar-group { margin-bottom: 4px; }
.sidebar-group__header {
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding: 6px 6px;
  cursor: pointer;
  border-radius: 6px;
  font-weight: 600;
}
.sidebar-group__header:hover { background: var(--code-bg); }
.sidebar-group__desc { font-weight: 400; font-size: 11px; color: var(--text-muted); }
.sidebar-group__items { padding-left: 14px; display: none; }
.sidebar-group.open .sidebar-group__items { display: block; }
.sidebar-group.open .sidebar-group__caret { transform: rotate(90deg); }
.sidebar-group__caret { display: inline-block; transition: transform 0.1s; font-size: 10px; }

.tree-file, .tree-dir {
  display: block;
  padding: 4px 6px;
  border-radius: 4px;
  cursor: pointer;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.tree-file:hover { background: var(--code-bg); }
.tree-file.active { background: var(--brand); color: #fff; }
.tree-dir { font-weight: 600; color: var(--text-muted); margin-top: 4px; }

.content { flex: 1; overflow-y: auto; padding: 24px 32px; min-width: 0; }

.welcome { max-width: 760px; }
.welcome h1 { font-size: 20px; }
.welcome p { color: var(--text-muted); line-height: 1.7; font-size: 14px; }
.welcome__categories {
  margin-top: 20px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 10px;
}
.category-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  font-size: 12px;
}
.category-card__name { font-weight: 600; margin-bottom: 4px; }
.category-card__desc { color: var(--text-muted); line-height: 1.5; }

.file-view { max-width: 900px; }
.file-view__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}
.file-view__path {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 13px;
  color: var(--text-muted);
}
.file-view__actions { display: flex; gap: 8px; }

.save-message {
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 12px;
  margin-bottom: 12px;
}
.save-message.success { background: color-mix(in srgb, var(--success) 15%, transparent); color: var(--success); }
.save-message.error { background: color-mix(in srgb, var(--danger) 15%, transparent); color: var(--danger); }

.render-pane { font-size: 14px; line-height: 1.75; }
.render-pane pre {
  background: var(--code-bg);
  padding: 12px;
  border-radius: 8px;
  overflow-x: auto;
  font-size: 12.5px;
}
.render-pane code {
  background: var(--code-bg);
  padding: 1px 5px;
  border-radius: 4px;
  font-size: 0.9em;
}
.render-pane pre code { background: none; padding: 0; }
.render-pane table { border-collapse: collapse; width: 100%; font-size: 13px; }
.render-pane th, .render-pane td { border: 1px solid var(--border); padding: 6px 10px; text-align: left; }
.render-pane th { background: var(--bg-alt); }
.render-pane h1, .render-pane h2, .render-pane h3 { border-bottom: 1px solid var(--border); padding-bottom: 6px; }
.render-pane blockquote { border-left: 3px solid var(--brand); margin: 0; padding: 4px 14px; color: var(--text-muted); }
.render-pane a { color: var(--brand); }
.render-pane.plain pre { white-space: pre-wrap; word-break: break-word; }

.edit-pane {
  width: 100%;
  min-height: 60vh;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 13px;
  line-height: 1.6;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--code-bg);
  color: var(--text);
  resize: vertical;
}

.modal {
  position: fixed; inset: 0;
  background: rgba(0, 0, 0, 0.45);
  display: flex; align-items: center; justify-content: center;
  z-index: 50;
}
.modal__box {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 20px;
  width: 320px;
  box-shadow: var(--shadow);
}
.modal__box h2 { margin: 0 0 8px; font-size: 16px; }
.modal__hint { font-size: 12px; color: var(--text-muted); margin: 0 0 12px; line-height: 1.5; }
.modal__box input {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--text);
  font-size: 13px;
  margin-bottom: 10px;
}
.modal__actions { display: flex; gap: 8px; justify-content: flex-end; }
.login-error { color: var(--danger); font-size: 12px; margin-bottom: 10px; }