/* ── THEME TOKENS ── */
    [data-theme="dark"] {
      --bg:           #0d1117;
      --surface:      #161b22;
      --surface2:     #1c2330;
      --border:       #30363d;
      --accent:       #58a6ff;
      --accent-green: #3fb950;
      --accent-orange:#f0883e;
      --text:         #e6edf3;
      --text-muted:   #8b949e;
      --text-faint:   #484f58;
      --code-bg:      #161b22;
      --code-border:  #30363d;
      --toc-active:   #58a6ff;
      --tag-fill:     rgba(88,166,255,0.12);
      --tag-border:   rgba(88,166,255,0.25);
      --blockquote-border: #3fb950;
      --blockquote-bg:rgba(63,185,80,0.06);
      --toggle-bg:    #21262d;
      --toggle-knob:  #58a6ff;
      --shadow:       rgba(0,0,0,0.4);
    }

    [data-theme="light"] {
      --bg:           #ffffff;
      --surface:      #f6f8fa;
      --surface2:     #eaeef2;
      --border:       #d0d7de;
      --accent:       #0969da;
      --accent-green: #1a7f37;
      --accent-orange:#bc4c00;
      --text:         #1f2328;
      --text-muted:   #656d76;
      --text-faint:   #afb8c1;
      --code-bg:      #f6f8fa;
      --code-border:  #d0d7de;
      --toc-active:   #0969da;
      --tag-fill:     rgba(9,105,218,0.08);
      --tag-border:   rgba(9,105,218,0.2);
      --blockquote-border: #1a7f37;
      --blockquote-bg:rgba(26,127,55,0.05);
      --toggle-bg:    #eaeef2;
      --toggle-knob:  #0969da;
      --shadow:       rgba(0,0,0,0.08);
    }

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

    html { scroll-behavior: smooth; }

    body {
      background: var(--bg);
      color: var(--text);
      font-family: 'IBM Plex Sans', sans-serif;
      font-size: 12px;
      line-height: 20px;
      transition: background 0.2s, color 0.2s;
    }

    /* ── HEADER ── */
    header {
      height: 60px;
      border-bottom: 1px solid var(--border);
      display: flex;
      align-items: center;
      padding: 0 40px;
      gap: 16px;
      position: sticky;
      top: 0;
      background: var(--bg);
      z-index: 100;
      transition: background 0.2s, border-color 0.2s;
    }

    .site-title {
      font-family: 'IBM Plex Mono', monospace;
      font-size: 15px;
      font-weight: 600;
      color: var(--text);
      text-decoration: none;
      flex: 1;
    }

    .header-right {
      display: flex;
      align-items: center;
      gap: 10px;
    }

    .nav-link {
      font-size: 12px;
      color: var(--text-muted);
      text-decoration: none;
      padding: 4px 10px;
      border-radius: 20px;
      border: 1px solid transparent;
      transition: all 0.15s;
    }

    .nav-link:hover {
      border-color: var(--border);
      color: var(--text);
    }

    /* ── THEME TOGGLE ── */
    .theme-toggle {
      width: 44px;
      height: 24px;
      background: var(--toggle-bg);
      border: 1px solid var(--border);
      border-radius: 12px;
      cursor: pointer;
      position: relative;
      transition: background 0.2s, border-color 0.2s;
      flex-shrink: 0;
    }

    .theme-toggle::after {
      content: '';
      position: absolute;
      width: 16px;
      height: 16px;
      border-radius: 50%;
      background: var(--toggle-knob);
      top: 3px;
      left: 3px;
      transition: transform 0.2s, background 0.2s;
    }

    [data-theme="light"] .theme-toggle::after {
      transform: translateX(20px);
    }

    .toggle-icon {
      font-size: 11px;
      color: var(--text-muted);
      user-select: none;
    }

    /* ── PAGE LAYOUT: sidebar + content ── */
    .page {
      max-width: 1160px;
      margin: 0 auto;
      padding: 48px 24px 80px;
      display: grid;
      grid-template-columns: 1fr 220px; 
      gap: 48px;
      align-items: start;
    }

    /* ── TOC SIDEBAR ── */
    .toc-sidebar {
      position: sticky;
      top: 80px;
    }

    .toc-label {
      font-family: 'IBM Plex Mono', monospace;
      font-size: 10px;
      font-weight: 600;
      text-transform: uppercase;
      letter-spacing: 1px;
      color: var(--text-faint);
      margin-bottom: 14px;
    }

    .toc-list {
      list-style: none;
      border-left: 1px solid var(--border);
    }

    .toc-list li a {
      display: block;
      padding: 5px 14px;
      font-size: 12.5px;
      color: var(--text-muted);
      text-decoration: none;
      border-left: 2px solid transparent;
      margin-left: -1px;
      transition: color 0.15s, border-color 0.15s;
      line-height: 1.5;
    }

    .toc-list li a:hover {
      color: var(--text);
    }

    .toc-list li a.active {
      color: var(--toc-active);
      border-left-color: var(--toc-active);
    }

    .toc-list .toc-h3 a {
      padding-left: 28px;
      font-size: 12px;
    }

    /* ── ARTICLE ── */
    article {
      min-width: 0;
    }

    /* post meta header */
    .post-meta {
      margin-bottom: 40px;
      padding-bottom: 28px;
      border-bottom: 1px solid var(--border);
    }

    .post-breadcrumb {
      display: flex;
      align-items: center;
      gap: 6px;
      font-size: 12px;
      color: var(--text-muted);
      margin-bottom: 18px;
      font-family: 'IBM Plex Mono', monospace;
    }

    .post-breadcrumb a { color: var(--accent); text-decoration: none; }
    .post-breadcrumb a:hover { text-decoration: underline; }
    .post-breadcrumb span { color: var(--text-faint); }

    .post-title {
      font-size: 26px;
      font-weight: 600;
      line-height: 1.3;
      letter-spacing: -0.4px;
      color: var(--text);
      margin-bottom: 16px;
    }

    .post-info {
      display: flex;
      gap: 16px;
      align-items: center;
      flex-wrap: wrap;
    }

    .post-date {
      font-family: 'IBM Plex Mono', monospace;
      font-size: 12px;
      color: var(--text-muted);
    }

    .post-tags {
      display: flex;
      gap: 6px;
      flex-wrap: wrap;
    }

    .tag {
      font-family: 'IBM Plex Mono', monospace;
      font-size: 11px;
      padding: 3px 9px;
      border-radius: 4px;
      border: 1px solid var(--tag-border);
      background: var(--tag-fill);
      color: var(--accent);
    }

    .tag-green { color: var(--accent-green); border-color: rgba(63,185,80,0.3); background: rgba(63,185,80,0.08); }
    .tag-orange { color: var(--accent-orange); border-color: rgba(240,136,62,0.3); background: rgba(240,136,62,0.08); }

    /* reading time */
    .read-time {
      font-size: 12px;
      color: var(--text-muted);
      margin-left: auto;
    }

    /* ── PROSE CONTENT ── */
    .prose h2 {
      font-size: 20px;
      font-weight: 600;
      color: var(--text);
      margin: 48px 0 16px;
      padding-bottom: 10px;
      border-bottom: 1px solid var(--border);
      scroll-margin-top: 80px;
    }

    .prose h3 {
      font-size: 16px;
      font-weight: 600;
      color: var(--text);
      margin: 32px 0 12px;
      scroll-margin-top: 80px;
    }

    .prose p {
      margin-bottom: 12px;
      color: var(--text);
    }

    .prose a {
      color: var(--accent);
      text-decoration: none;
    }

    .prose a:hover { text-decoration: underline; }

    .prose ul, .prose ol {
      margin: 12px 0 20px 20px;
      color: var(--text);
    }

    .prose li { margin-bottom: 6px; }

    /* inline code */
    .prose code {
      font-family: 'IBM Plex Mono', monospace;
      font-size: 11px;
      background: var(--code-bg);
      border: 1px solid var(--code-border);
      border-radius: 4px;
      padding: 1px 6px;
      color: var(--accent-green);
    }

    /* code block */
    .prose pre {
      background: var(--code-bg);
      border: 1px solid var(--code-border);
      border-radius: 8px;
      padding: 20px;
      overflow-x: auto;
      margin: 20px 0 28px;
      position: relative;
    }

    .prose pre code {
      background: none;
      border: none;
      padding: 0;
      font-size: 12px;
      color: var(--text);
      line-height: 12px;
    }

    .pre-label {
      position: absolute;
      top: 10px;
      right: 14px;
      font-family: 'IBM Plex Mono', monospace;
      font-size: 10px;
      color: var(--text-faint);
      letter-spacing: 0.5px;
      text-transform: uppercase;
    }

    /* blockquote */
    .prose blockquote {
      border-left: 3px solid var(--blockquote-border);
      background: var(--blockquote-bg);
      padding: 14px 20px;
      border-radius: 0 6px 6px 0;
      margin: 20px 0 28px;
      color: var(--text-muted);
      font-size: 14px;
    }

    /* info callout */
    .callout {
      border: 1px solid var(--border);
      border-left: 3px solid var(--accent);
      background: var(--surface);
      border-radius: 0 8px 8px 0;
      padding: 14px 18px;
      margin: 20px 0 28px;
      font-size: 13.5px;
    }

    .callout-title {
      font-family: 'IBM Plex Mono', monospace;
      font-size: 11px;
      font-weight: 600;
      text-transform: uppercase;
      letter-spacing: 0.6px;
      color: var(--accent);
      margin-bottom: 6px;
    }

    /* table */
    .prose table {
      width: 100%;
      border-collapse: collapse;
      margin: 20px 0 28px;
      font-size: 13.5px;
    }

    .prose th {
      background: var(--surface2);
      text-align: left;
      padding: 10px 14px;
      font-weight: 600;
      font-size: 11px;
      text-transform: uppercase;
      letter-spacing: 0.6px;
      color: var(--text-muted);
      border-bottom: 1px solid var(--border);
    }

    .prose td {
      padding: 10px 14px;
      border-bottom: 1px solid var(--border);
      color: var(--text);
      vertical-align: top;
    }

    .prose td code { font-size: 12px; }

    .prose tr:last-child td { border-bottom: none; }

    /* separator */
    .prose hr {
      border: none;
      border-top: 1px solid var(--border);
      margin: 40px 0;
    }

    img {
    max-width: 840px;
     }
    /* ── POST NAV ── */
    .post-nav {
      display: flex;
      justify-content: space-between;
      gap: 16px;
      margin-top: 56px;
      padding-top: 28px;
      border-top: 1px solid var(--border);
    }

    .post-nav a {
      font-size: 13px;
      color: var(--accent);
      text-decoration: none;
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .post-nav a:hover { text-decoration: underline; }
    .post-nav .nav-label {
      font-size: 11px;
      color: var(--text-faint);
      font-family: 'IBM Plex Mono', monospace;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      display: block;
      margin-bottom: 4px;
    }

    /* ── RESPONSIVE ── */
    @media (max-width: 820px) {
      .page { grid-template-columns: 1fr; gap: 32px; }
      .toc-sidebar { position: static; }
      header { padding: 0 16px; }
    }