/* paper — knowledge blog */
:root {
  --bg: #f7f4ef;
  --bg-deep: #efe8df;
  --surface: #fffdf9;
  --ink: #1f1a14;
  --muted: #7a6f62;
  --line: #e4dccf;
  --accent: #0f766e;
  --accent-2: #c2410c;
  --accent-soft: #d8f3ef;
  --accent-ink: #0b5c56;
  --radius: 14px;
  --wrap: 720px;
  --font: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, sans-serif;
  --serif: "Songti SC", "Noto Serif SC", "Georgia", serif;
  --shadow: 0 10px 30px rgba(31, 26, 20, 0.06);
}

* { box-sizing: border-box; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(1200px 500px at 10% -10%, #efe7da 0%, transparent 55%),
    radial-gradient(900px 420px at 100% 0%, #dceeeb 0%, transparent 50%),
    var(--bg);
  line-height: 1.8;
  min-height: 100vh;
}

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

.wrap {
  width: min(100% - 2.5rem, var(--wrap));
  margin-inline: auto;
}

/* header */
.site-header {
  border-bottom: 1px solid rgba(228, 220, 207, 0.9);
  background: rgba(247, 244, 239, 0.85);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 10;
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 3.75rem;
  gap: 1rem;
}
.logo {
  font-weight: 750;
  color: var(--ink);
  letter-spacing: 0.02em;
  font-size: 1.05rem;
}
.logo:hover { text-decoration: none; color: var(--accent); }
.nav {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
}
.nav a {
  color: var(--muted);
  font-size: 0.92rem;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
}
.nav a:hover {
  color: var(--accent-ink);
  text-decoration: none;
  background: rgba(15, 118, 110, 0.08);
}
.nav a.active {
  color: var(--accent-ink);
  background: var(--accent-soft);
  font-weight: 600;
}

/* hero */
.hero {
  padding: 3.25rem 0 1.25rem;
}
.hero h1,
.page-head h1,
.article-head h1 {
  font-family: var(--serif);
  font-size: clamp(1.9rem, 4.5vw, 2.55rem);
  line-height: 1.25;
  margin: 0 0 0.85rem;
  letter-spacing: 0.01em;
}
.hero .lead,
.page-head .lead,
.article-head .lead {
  color: var(--muted);
  font-size: 1.12rem;
  margin: 0;
  max-width: 36em;
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.5rem;
}
.btn,
.btn-ghost {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.62rem 1.2rem;
  border-radius: 999px;
  font-size: 0.95rem;
  border: 1px solid transparent;
}
.btn {
  background: var(--accent);
  color: #fff;
}
.btn:hover {
  text-decoration: none;
  color: #fff;
  filter: brightness(1.06);
}
.btn-ghost {
  background: transparent;
  border-color: var(--line);
  color: var(--ink);
}
.btn-ghost:hover {
  text-decoration: none;
  border-color: var(--accent);
  color: var(--accent-ink);
  background: rgba(15, 118, 110, 0.05);
}

.page-head { padding: 2.75rem 0 1.15rem; }
.section { padding: 1.35rem 0 1.85rem; }
.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 1rem;
  gap: 1rem;
}
.section-head h2 {
  font-size: 1.12rem;
  margin: 0;
  font-weight: 700;
}
.section-head h2::before {
  content: "";
  display: inline-block;
  width: 0.45rem;
  height: 0.45rem;
  border-radius: 999px;
  background: var(--accent);
  margin-right: 0.55rem;
  vertical-align: middle;
}
.more {
  font-size: 0.9rem;
  color: var(--muted);
}
.more:hover { color: var(--accent); }

/* cards */
.card-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.9rem;
}
.card a {
  display: block;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.2rem 1.35rem;
  color: inherit;
  box-shadow: 0 1px 0 rgba(31, 26, 20, 0.02);
  transition: transform 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease;
}
.card a:hover {
  text-decoration: none;
  border-color: rgba(15, 118, 110, 0.45);
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}
.card-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  color: var(--muted);
  font-size: 0.84rem;
  margin-bottom: 0.4rem;
}
.card-title {
  display: block;
  font-weight: 700;
  font-size: 1.08rem;
  margin-bottom: 0.3rem;
  letter-spacing: 0.01em;
}
.card-desc {
  display: block;
  color: var(--muted);
  font-size: 0.94rem;
  line-height: 1.7;
}
.tag {
  display: inline-block;
  background: var(--accent-soft);
  color: var(--accent-ink);
  border-radius: 999px;
  padding: 0.08rem 0.6rem;
  font-size: 0.78rem;
  text-decoration: none;
}
a.tag:hover {
  filter: brightness(0.97);
  text-decoration: none;
}
.empty {
  color: var(--muted);
  padding: 1.35rem 1.15rem;
  list-style: none;
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  background: rgba(255, 253, 249, 0.5);
}

/* article */
.article { padding: 1.5rem 0 3rem; }
.article-head {
  margin-bottom: 1.85rem;
  padding-bottom: 1.35rem;
  border-bottom: 1px solid var(--line);
}
.ext-link {
  font-size: 0.92rem;
  color: var(--muted);
  word-break: break-all;
}
.content {
  font-size: 1.06rem;
}
.content > :first-child { margin-top: 0; }
.content h2 {
  font-family: var(--serif);
  font-size: 1.42rem;
  margin: 2.1rem 0 0.85rem;
}
.content h3 {
  font-size: 1.16rem;
  margin: 1.55rem 0 0.55rem;
}
.content p { margin: 0 0 1.05rem; }
.content ul, .content ol { padding-left: 1.35rem; }
.content li { margin: 0.35rem 0; }
.content blockquote {
  margin: 1.35rem 0;
  padding: 0.95rem 1.15rem;
  border-left: 3px solid var(--accent);
  background: var(--surface);
  color: var(--muted);
  border-radius: 0 var(--radius) var(--radius) 0;
  box-shadow: var(--shadow);
}
.content code {
  background: #ebe4d8;
  padding: 0.12rem 0.4rem;
  border-radius: 5px;
  font-size: 0.9em;
}
.content pre {
  overflow-x: auto;
  padding: 1.05rem 1.25rem;
  border-radius: var(--radius);
  background: #1f1a14;
  color: #f5f0e8;
  box-shadow: var(--shadow);
}
.content pre code {
  background: transparent;
  padding: 0;
  color: inherit;
}
.content img {
  max-width: 100%;
  border-radius: var(--radius);
  display: block;
}
.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.15rem 0;
  font-size: 0.96rem;
  background: var(--surface);
  border-radius: var(--radius);
  overflow: hidden;
}
.content th, .content td {
  border: 1px solid var(--line);
  padding: 0.65rem 0.85rem;
  text-align: left;
}
.content th {
  background: rgba(15, 118, 110, 0.06);
  font-weight: 650;
}

.cta { margin-top: 2.15rem; }

.post-nav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.5rem 0 2.5rem;
  border-top: 1px solid var(--line);
  font-size: 0.92rem;
  flex-wrap: wrap;
}

/* pagination */
.pagination {
  display: flex;
  gap: 0.55rem;
  list-style: none;
  padding: 1.5rem 0 2rem;
}
.pagination li a {
  display: inline-block;
  padding: 0.35rem 0.75rem;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.pagination .active a {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  font-weight: 700;
}

/* footer */
.site-footer {
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.88rem;
  padding: 1.65rem 0 2.75rem;
  margin-top: 1rem;
}
.site-footer p { margin: 0; }

@media (max-width: 640px) {
  .site-header .wrap {
    flex-direction: column;
    align-items: flex-start;
    padding: 0.9rem 0;
  }
  .hero { padding-top: 2.15rem; }
  .nav { margin-left: -0.45rem; }
}