:root {
  --bg: #ffffff;
  --bg-soft: #f7f8fa;
  --text: #1f2328;
  --text-soft: #59636e;
  --border: #e5e7eb;
  --accent: #2563eb;
  --accent-soft: #eff4ff;
  --radius: 12px;
  --maxw: 760px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  border-bottom: 1px solid var(--border);
  background: rgba(255,255,255,0.85);
  backdrop-filter: saturate(180%) blur(8px);
  position: sticky;
  top: 0;
  z-index: 10;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.logo { font-weight: 700; font-size: 18px; color: var(--text); }
.logo:hover { text-decoration: none; }
.nav a { margin-left: 18px; color: var(--text-soft); font-size: 15px; }
.nav a:hover { color: var(--accent); text-decoration: none; }

/* Main */
.main { padding: 40px 20px 64px; min-height: 60vh; }

/* Post list */
.post-list { list-style: none; padding: 0; margin: 0; }
.post-item {
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
}
.post-item:last-child { border-bottom: none; }
.post-item h2 { margin: 0 0 6px; font-size: 20px; }
.post-item h2 a { color: var(--text); }
.post-item h2 a:hover { color: var(--accent); text-decoration: none; }
.post-meta { color: var(--text-soft); font-size: 13px; margin-bottom: 8px; }
.post-summary { color: var(--text-soft); margin: 0; }

/* Article */
.article h1 { font-size: 28px; margin: 0 0 8px; }
.article .post-meta { margin-bottom: 24px; }
.article-content { font-size: 16px; }
.article-content h2 { font-size: 22px; margin: 32px 0 12px; }
.article-content h3 { font-size: 18px; margin: 24px 0 10px; }
.article-content p { margin: 14px 0; }
.article-content img { max-width: 100%; border-radius: var(--radius); }
.article-content pre {
  background: var(--bg-soft);
  padding: 16px;
  border-radius: var(--radius);
  overflow-x: auto;
  border: 1px solid var(--border);
}
.article-content code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 14px;
}
.article-content :not(pre) > code {
  background: var(--accent-soft);
  padding: 2px 6px;
  border-radius: 6px;
  color: var(--accent);
}
.article-content blockquote {
  margin: 16px 0;
  padding: 8px 16px;
  border-left: 4px solid var(--accent);
  background: var(--bg-soft);
  color: var(--text-soft);
  border-radius: 0 var(--radius) var(--radius) 0;
}

/* Tags */
.tags { margin-top: 28px; }
.tag {
  display: inline-block;
  background: var(--bg-soft);
  color: var(--text-soft);
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 13px;
  margin: 0 6px 6px 0;
}
.tag:hover { background: var(--accent-soft); color: var(--accent); text-decoration: none; }

/* Archive */
.archive-year { margin: 28px 0 12px; font-size: 14px; color: var(--text-soft); letter-spacing: 1px; }
.archive-list { list-style: none; padding: 0; margin: 0; }
.archive-list li { display: flex; gap: 12px; padding: 6px 0; }
.archive-list time { color: var(--text-soft); font-size: 14px; flex: 0 0 90px; }
.archive-list a { color: var(--text); }
.archive-list a:hover { color: var(--accent); }

/* About */
.page-title { font-size: 26px; margin: 0 0 20px; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  color: var(--text-soft);
  font-size: 14px;
  text-align: center;
}
.site-footer .social a { margin: 0 8px; color: var(--text-soft); }
.site-footer .site-stats { margin: 6px 0 0; font-size: 13px; opacity: 0.8; }

/* Guestbook */
.gb-form {
  margin: 8px 0 8px;
  padding: 20px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-soft);
}
.gb-row { margin-bottom: 12px; }
.gb-form input[type="text"],
.gb-form textarea {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  font-family: inherit;
  resize: vertical;
}
.gb-form textarea { min-height: 96px; }
.gb-form input:focus,
.gb-form textarea:focus { outline: none; border-color: var(--accent); }
.gb-hp {
  position: absolute;
  left: -9999px;
  width: 1px; height: 1px;
  overflow: hidden;
}
.gb-actions { display: flex; align-items: center; gap: 14px; margin-bottom: 0; }
.gb-form button {
  padding: 9px 22px;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-size: 15px;
  cursor: pointer;
}
.gb-form button:hover { opacity: 0.9; }
.gb-msg { font-size: 14px; }
.gb-msg.gb-ok { color: #1a7f37; }
.gb-msg.gb-err { color: #cf222e; }

.gb-list-title { font-size: 20px; margin: 32px 0 12px; }
.gb-list { list-style: none; padding: 0; margin: 0; }
.gb-list li {
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
}
.gb-head { display: flex; align-items: baseline; gap: 10px; margin-bottom: 4px; }
.gb-name { font-weight: 600; color: var(--text); }
.gb-time { font-size: 12px; color: var(--text-soft); }
.gb-content { color: var(--text); white-space: pre-wrap; word-break: break-word; }
.gb-empty { color: var(--text-soft); }

/* Responsive */
@media (max-width: 600px) {
  .main { padding: 28px 16px 48px; }
  .article h1 { font-size: 24px; }
  .nav a { margin-left: 12px; font-size: 14px; }
}

/* Dark mode */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --bg-soft: #161b22;
    --text: #e6edf3;
    --text-soft: #8b949e;
    --border: #30363d;
    --accent: #58a6ff;
    --accent-soft: #1f2d44;
  }
  .site-header { background: rgba(13,17,23,0.85); }
}