/* Fukasawa 主题：bento 网格卡片风（浅灰底、圆角卡片、悬浮阴影） */
:root {
  --fk-bg: #f1f2f4; --fk-card: #ffffff; --fk-text: #1f2328; --fk-muted: #8b949e;
  --fk-border: #e6e8eb; --fk-accent: #0969da; --fk-code-bg: #f6f8fa;
  --fk-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
}
html.dark {
  --fk-bg: #0d1117; --fk-card: #161b22; --fk-text: #e6edf3; --fk-muted: #8b949e;
  --fk-border: #30363d; --fk-accent: #58a6ff; --fk-code-bg: #161b22;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--fk-bg); color: var(--fk-text);
  font-family: var(--fk-sans); line-height: 1.75; font-size: 15.5px; }
a { color: inherit; text-decoration: none; }

.fk-header { background: var(--fk-card); border-bottom: 1px solid var(--fk-border);
  position: sticky; top: 0; z-index: 20; }
.fk-header-inner, .fk-main, .fk-footer { max-width: 1080px; margin: 0 auto; padding: 0 20px; }
.fk-header-inner { display: flex; justify-content: space-between; align-items: center; height: 56px; }
.fk-brand { display: flex; align-items: center; gap: 10px; font-weight: 700; }
.fk-avatar { width: 30px; height: 30px; border-radius: 50%; object-fit: cover; }
.fk-nav { display: flex; gap: 16px; align-items: center; }
.fk-nav a { color: var(--fk-muted); font-size: 14px; }
.fk-nav a:hover { color: var(--fk-accent); }
.dark-toggle { background: none; border: none; cursor: pointer; font-size: 15px; }

.fk-userbar { display: flex; align-items: center; gap: 14px; padding: 18px 0 6px;
  color: var(--fk-muted); font-size: 14px; white-space: nowrap; overflow-x: auto; }
.fk-userbar > * { flex: 0 0 auto; }
.fk-link { color: var(--fk-muted); padding: 4px 12px; border: 1px solid var(--fk-border);
  border-radius: 6px; background: var(--fk-card); }
.fk-link:hover { color: var(--fk-accent); border-color: var(--fk-accent); }
.fk-manage { color: var(--fk-accent); }

.fk-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; padding: 16px 0 48px; }
.fk-card { background: var(--fk-card); border: 1px solid var(--fk-border); border-radius: 12px;
  overflow: hidden; display: flex; flex-direction: column;
  transition: transform .18s ease, box-shadow .18s ease; }
.fk-card:hover { transform: translateY(-3px); box-shadow: 0 10px 26px rgba(0,0,0,.09); }
.fk-card-cover { width: 100%; height: 150px; object-fit: cover; display: block; }
.fk-card-body { padding: 14px 16px 16px; display: flex; flex-direction: column; flex: 1; }
.fk-card-title { margin: 0 0 6px; font-size: 16px; line-height: 1.4; }
.fk-card:hover .fk-card-title { color: var(--fk-accent); }
.fk-card-summary { margin: 0 0 10px; color: var(--fk-muted); font-size: 13px;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.fk-card-meta { margin-top: auto; color: var(--fk-muted); font-size: 12px; }
.fk-empty { grid-column: 1 / -1; text-align: center; color: var(--fk-muted); padding: 60px 0; }

.fk-post { background: var(--fk-card); border: 1px solid var(--fk-border); border-radius: 12px;
  padding: 36px 40px; margin: 24px 0 48px; max-width: 820px; }
.fk-post-title { font-size: 30px; margin: 0 0 10px; }
.fk-post-meta { color: var(--fk-muted); font-size: 14px; display: flex; gap: 8px;
  align-items: center; flex-wrap: wrap; }
.meta-avatar { width: 20px; height: 20px; border-radius: 50%; object-fit: cover; }
.fk-draft { background: #fff3cd; color: #8a6d1f; padding: 1px 8px; border-radius: 8px; font-size: 12px; }
html.dark .fk-draft { background: #3a3325; color: #c9a94f; }
.fk-cover { width: 100%; border-radius: 10px; margin: 16px 0; }
.fk-page-title { font-size: 26px; }

/* nb-* 块样式 */
.nb-h2 { font-size: 23px; margin: 34px 0 12px; scroll-margin-top: 70px; }
.nb-h3 { font-size: 19px; margin: 24px 0 10px; scroll-margin-top: 70px; }
.nb-p { margin: 12px 0; }
.nb-quote { margin: 16px 0; padding: 12px 18px; background: var(--fk-code-bg);
  border-left: 4px solid var(--fk-accent); border-radius: 0 8px 8px 0; color: var(--fk-muted); }
.nb-code { background: var(--fk-code-bg); border-radius: 10px; padding: 14px;
  overflow-x: auto; margin: 16px 0; font-size: 13.5px; }
.nb-code code { font-family: ui-monospace, "SF Mono", Consolas, monospace; }
.nb-code code[data-lang]::before { content: attr(data-lang); display: block;
  color: var(--fk-muted); font-size: 11px; margin-bottom: 4px; text-transform: uppercase; }
.nb-list { padding-left: 26px; }
.nb-image { margin: 18px 0; text-align: center; }
.nb-image img { max-width: 100%; border-radius: 10px; }
.nb-image figcaption { color: var(--fk-muted); font-size: 13px; margin-top: 6px; }
.nb-link { display: flex; flex-direction: column; gap: 2px; margin: 14px 0; padding: 12px 16px;
  border: 1px solid var(--fk-border); border-radius: 10px; }
.nb-link:hover { border-color: var(--fk-accent); }
.nb-link-title { color: var(--fk-accent); font-weight: 500; }
.nb-link-url { color: var(--fk-muted); font-size: 13px; }
.toc-mobile { display: none; background: var(--fk-code-bg); border-radius: 8px;
  padding: 8px 16px; margin-bottom: 16px; font-size: 14px; }
.toc-mobile ul { list-style: none; padding-left: 8px; }
.toc-mobile .toc-level-3 { padding-left: 14px; }

/* 评论（同 simple 语义） */
.nb-comments { margin-top: 36px; border-top: 1px solid var(--fk-border); padding-top: 20px; }
.nb-comments-title { font-size: 18px; }
.nb-comment { display: flex; gap: 10px; padding: 12px 0; border-bottom: 1px solid var(--fk-border); }
.nb-comment-avatar { width: 32px; height: 32px; border-radius: 50%; object-fit: cover; flex-shrink: 0; }
.nb-comment-avatar-ph { background: var(--fk-code-bg); display: inline-block; }
.nb-comment-body { flex: 1; }
.nb-comment-head { font-size: 14px; display: flex; gap: 8px; align-items: baseline; }
.nb-comment-time { color: var(--fk-muted); font-size: 12px; }
.nb-comment-content { margin-top: 4px; white-space: pre-wrap; word-break: break-word; }
.nb-comment-del { border: none; background: none; color: var(--fk-accent); cursor: pointer; font-size: 12px; }
.nb-comment-hint { color: var(--fk-muted); font-size: 14px; }
.nb-comment-form { margin-top: 16px; }
.nb-comment-form textarea { width: 100%; padding: 10px 12px; border: 1px solid var(--fk-border);
  border-radius: 8px; font-family: inherit; font-size: 14px; background: var(--fk-card);
  color: var(--fk-text); resize: vertical; }
.nb-comment-btn { margin-top: 8px; padding: 7px 18px; border: none; border-radius: 8px;
  background: var(--fk-accent); color: #fff; cursor: pointer; font-size: 14px; }
.nb-comment-login { color: var(--fk-accent); font-size: 14px; }

.fk-around { display: flex; justify-content: space-between; gap: 12px; margin-top: 36px; }
.fk-around-link { flex: 1; max-width: 48%; border: 1px solid var(--fk-border); border-radius: 10px;
  padding: 10px 14px; font-size: 14px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.fk-around-link:hover { border-color: var(--fk-accent); color: var(--fk-accent); }
.fk-year h2 { font-size: 17px; color: var(--fk-accent); }
.fk-archive { list-style: none; padding: 0; }
.fk-archive li { display: flex; gap: 12px; padding: 4px 0; }
.fk-archive li a:hover { color: var(--fk-accent); }
.fk-date { color: var(--fk-muted); font-size: 13px; }
.fk-footer { color: var(--fk-muted); font-size: 13px; padding: 20px 20px 40px; text-align: center; }
.preview-banner { background: #fff7ed; color: #b45309; border: 1px solid #fdba74;
  border-radius: 8px; padding: 8px 14px; font-size: 14px; margin-bottom: 16px; }

#jump-to-top { position: fixed; right: 20px; bottom: 24px; width: 38px; height: 38px;
  border-radius: 50%; border: 1px solid var(--fk-border); background: var(--fk-card);
  color: var(--fk-text); cursor: pointer; opacity: 0; pointer-events: none; transition: opacity .2s; z-index: 50; }
#jump-to-top.show { opacity: 1; pointer-events: auto; }

@media (max-width: 900px) { .fk-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) {
  .fk-grid { grid-template-columns: 1fr; }
  .fk-post { padding: 22px 18px; }
  .toc-mobile { display: block; }
  .fk-post-title { font-size: 24px; }
  .fk-around-link { max-width: none; }
}

/* 页脚沉底：内容不足时页脚贴底 */
body { display: flex; flex-direction: column; min-height: 100vh; }
body > main { flex: 1 0 auto; }
body > footer { flex-shrink: 0; margin-top: auto; }

/* 三级标题（h4） */
.nb-h4 { font-size: 18px; font-weight: 600; margin: 24px 0 8px; scroll-margin-top: 80px; }