/* =====================================================================
   Paper 主题：纸张阅读风（与 simple 共享 nb-* 块样式命名）
   暖纸底色 / serif 标题 / 细分隔线
   ===================================================================== */
:root {
  --paper-bg: #faf7f0;
  --paper-card: #fffdf8;
  --paper-text: #3d3a34;
  --paper-muted: #8b8578;
  --paper-border: #e6e0d4;
  --paper-accent: #b4632c;
  --paper-code-bg: #f3efe6;
  --paper-quote-bg: #f6f2e9;
  --paper-serif: "Noto Serif SC", "Songti SC", Georgia, serif;
  --paper-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
}
html.dark {
  --paper-bg: #1a1815;
  --paper-card: #211e1a;
  --paper-text: #d8d3c8;
  --paper-muted: #97907f;
  --paper-border: #35312a;
  --paper-code-bg: #26221d;
  --paper-quote-bg: #26221d;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0; background: var(--paper-bg); color: var(--paper-text);
  font-family: var(--paper-sans); line-height: 1.8; font-size: 16px;
}

/* Header */
.paper-header { border-bottom: 1px solid var(--paper-border); background: var(--paper-card); }
.paper-header-inner, .paper-main, .paper-footer { max-width: 720px; margin: 0 auto; padding: 0 20px; }
.paper-header-inner { display: flex; justify-content: space-between; align-items: center; height: 60px; }
.paper-home { display: flex; align-items: center; gap: 10px; text-decoration: none; color: inherit; }
.paper-avatar { width: 32px; height: 32px; border-radius: 50%; object-fit: cover; }
.paper-author { font-family: var(--paper-serif); font-weight: 600; font-size: 17px; }
.paper-nav { display: flex; gap: 18px; align-items: center; }
.paper-nav a { color: var(--paper-muted); text-decoration: none; font-size: 14px; }
.paper-nav a:hover { color: var(--paper-accent); }
.dark-toggle { background: none; border: none; cursor: pointer; font-size: 16px; }

/* 列表 */
.paper-list { padding: 32px 0; }
.paper-item { padding: 22px 0; border-bottom: 1px dashed var(--paper-border); }
.paper-item-title { margin: 0 0 6px; font-size: 21px; font-family: var(--paper-serif); }
.paper-item-title a { color: var(--paper-text); text-decoration: none; }
.paper-item-title a:hover { color: var(--paper-accent); }
.paper-item-meta { font-size: 13px; color: var(--paper-muted); display: flex; gap: 8px; align-items: center; }
.paper-item-summary { margin: 8px 0 0; color: var(--paper-muted); font-size: 14px; }
.paper-empty { text-align: center; color: var(--paper-muted); padding: 64px 0; }

/* 文章页 */
.paper-post { background: var(--paper-card); border: 1px solid var(--paper-border);
  border-radius: 6px; padding: 40px 44px; margin: 32px 0; box-shadow: 0 1px 3px rgba(60,50,30,.06); }
.paper-post-title { font-family: var(--paper-serif); font-size: 30px; margin: 0 0 10px; }
.paper-draft-tag { background: #f3e3c2; color: #8a6d1f; padding: 1px 8px; border-radius: 8px; font-size: 12px; }
html.dark .paper-draft-tag { background: #3a3325; color: #c9a94f; }
.paper-cover { width: 100%; border-radius: 6px; margin-bottom: 20px; }
.paper-page-title { font-family: var(--paper-serif); }

/* 块样式（与 simple 相同的 nb-* 语义） */
.nb-h2 { font-family: var(--paper-serif); font-size: 24px; margin: 36px 0 12px; scroll-margin-top: 70px; }
.nb-h3 { font-family: var(--paper-serif); font-size: 19px; margin: 26px 0 10px; scroll-margin-top: 70px; }
.nb-p { margin: 12px 0; }
.nb-quote { margin: 16px 0; padding: 12px 18px; background: var(--paper-quote-bg);
  border-left: 3px solid var(--paper-accent); border-radius: 0 6px 6px 0; color: var(--paper-muted); }
.nb-code { background: var(--paper-code-bg); border-radius: 8px; padding: 14px;
  overflow-x: auto; margin: 16px 0; font-size: 13.5px; line-height: 1.6; }
.nb-code code { font-family: ui-monospace, "SF Mono", Consolas, Menlo, monospace; }
.nb-code code[data-lang]::before { content: attr(data-lang); display: block;
  color: var(--paper-muted); font-size: 11px; margin-bottom: 4px; text-transform: uppercase; }
.nb-list { padding-left: 26px; }
.nb-image { margin: 20px 0; text-align: center; }
.nb-image img { max-width: 100%; border-radius: 6px; }
.nb-image figcaption { color: var(--paper-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(--paper-border); border-radius: 8px; text-decoration: none;
  transition: border-color .15s; }
.nb-link:hover { border-color: var(--paper-accent); }
.nb-link-title { color: var(--paper-text); font-weight: 500; }
.nb-link-url { color: var(--paper-muted); font-size: 13px; }

/* 文章元信息 */
.meta-avatar, .item-avatar { width: 20px; height: 20px; border-radius: 50%;
  object-fit: cover; vertical-align: -6px; }

/* TOC（复用 simple 的类名结构） */
.toc-mobile { display: none; background: var(--paper-quote-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; }

/* 上一篇/下一篇、推荐 */
.article-around { display: flex; justify-content: space-between; gap: 12px; margin: 40px 0 20px; }
.around-link { flex: 1; max-width: 48%; border: 1px solid var(--paper-border); border-radius: 8px;
  padding: 10px 14px; font-size: 14px; color: var(--paper-text); text-decoration: none;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.around-link:hover { border-color: var(--paper-accent); color: var(--paper-accent); }
.around-next { text-align: right; }
.recommend { border-top: 1px solid var(--paper-border); padding-top: 20px; }
.recommend-title { font-family: var(--paper-serif); }
.recommend ul { list-style: none; padding: 0; margin: 0; }
.recommend li { display: flex; justify-content: space-between; padding: 5px 0; }
.recommend li a { color: var(--paper-text); text-decoration: none; }
.recommend li a:hover { color: var(--paper-accent); }
.archive-date { color: var(--paper-muted); font-size: 13px; }
.archive-year-title { font-family: var(--paper-serif); font-size: 16px; color: var(--paper-accent); }
.archive-list { list-style: none; padding: 0; }
.archive-list li { display: flex; gap: 12px; padding: 4px 0; }
.archive-list li a { color: var(--paper-text); text-decoration: none; }
.archive-list li a:hover { color: var(--paper-accent); }

/* 评论区（同 simple 语义） */
.nb-comments { margin-top: 40px; border-top: 1px solid var(--paper-border); padding-top: 20px; }
.nb-comments-title { font-family: var(--paper-serif); }
.nb-comment { display: flex; gap: 10px; padding: 12px 0; border-bottom: 1px dashed var(--paper-border); }
.nb-comment-avatar { width: 32px; height: 32px; border-radius: 50%; object-fit: cover; flex-shrink: 0; }
.nb-comment-avatar-ph { background: var(--paper-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(--paper-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(--paper-accent); cursor: pointer; font-size: 12px; }
.nb-comment-hint { color: var(--paper-muted); font-size: 14px; }
.nb-comment-form { margin-top: 16px; }
.nb-comment-form textarea { width: 100%; padding: 10px 12px; border: 1px solid var(--paper-border);
  border-radius: 8px; font-family: inherit; font-size: 14px; background: var(--paper-card);
  color: var(--paper-text); resize: vertical; }
.nb-comment-btn { margin-top: 8px; padding: 7px 18px; border: none; border-radius: 8px;
  background: var(--paper-accent); color: #fff; cursor: pointer; font-size: 14px; }
.nb-comment-login { color: var(--paper-accent); font-size: 14px; }

/* Footer / 返回顶部 */
.paper-footer { color: var(--paper-muted); font-size: 13px; padding: 24px 20px 40px; text-align: center; }
#jump-to-top { position: fixed; right: 20px; bottom: 24px; width: 38px; height: 38px;
  border-radius: 50%; border: 1px solid var(--paper-border); background: var(--paper-card);
  color: var(--paper-text); cursor: pointer; opacity: 0; pointer-events: none;
  transition: opacity .2s; z-index: 50; }
#jump-to-top.show { opacity: 1; pointer-events: auto; }

.preview-banner { background: #fff7ed; color: #b45309; border: 1px solid #fdba74;
  border-radius: 8px; padding: 8px 14px; font-size: 14px; margin-bottom: 16px; }

@media (max-width: 640px) {
  .paper-post { padding: 24px 20px; }
  .toc-mobile { display: block; }
  .paper-post-title { font-size: 24px; }
  .around-link { max-width: none; }
}

/* 用户前端顶栏（页面最上方） */
.paper-userbar { display: flex; align-items: center; gap: 14px; max-width: 720px;
  margin: 0 auto; padding: 14px 20px 0; color: var(--paper-muted); font-size: 14px;
  white-space: nowrap; overflow-x: auto; }
.paper-userbar > * { flex: 0 0 auto; }
.paper-userbar a { color: var(--paper-muted); }
.paper-userbar a:hover { color: var(--paper-accent); }
.paper-manage { padding: 3px 12px; border: 1px solid var(--paper-border);
  border-radius: 999px; color: var(--paper-accent) !important; }

/* 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; }