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

:root {
  --bg: #fafaf8;
  --surface: #ffffff;
  --border: #e8e6e1;
  --text: #1a1a1a;
  --text-muted: #6b6b6b;
  --accent: #2563eb;
  --accent-light: #eff6ff;
  --code-bg: #f4f4f0;
  --tag-bg: #f0f0eb;
  --serif: 'Georgia', 'Noto Serif SC', serif;
  --sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
  --max-w: 720px;
  --radius: 6px;
}

html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

/* ── Layout ── */

.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  font-weight: 700;
  font-size: 1rem;
  color: var(--text);
  letter-spacing: -0.02em;
}

.site-logo span { color: var(--accent); }

.site-nav a {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-left: 24px;
  transition: color 0.15s;
}

.site-nav a:hover { color: var(--accent); text-decoration: none; }

.main-content {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 48px 24px 96px;
}

/* ── Index ── */

.index-hero { margin-bottom: 56px; }

.index-hero h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 12px;
}

.index-hero p {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 480px;
}

.posts-section h2 {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.post-card {
  display: block;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 16px;
  transition: border-color 0.15s, box-shadow 0.15s;
  color: var(--text);
  text-decoration: none;
}

.post-card:hover {
  border-color: var(--accent);
  box-shadow: 0 2px 16px rgba(37, 99, 235, 0.08);
  text-decoration: none;
}

.post-card-header {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 8px;
}

.post-icon {
  font-size: 1.5rem;
  line-height: 1;
  flex-shrink: 0;
  margin-top: 2px;
}

.post-card-title {
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text);
}

.post-card-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-left: 36px;
}

.post-card-meta {
  margin-top: 12px;
  margin-left: 36px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.tag {
  font-size: 0.72rem;
  padding: 2px 8px;
  background: var(--tag-bg);
  border-radius: 99px;
  color: var(--text-muted);
  font-weight: 500;
}

.post-date {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ── Article ── */

.article-header { margin-bottom: 48px; }

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 32px;
  transition: color 0.15s;
}

.back-link:hover { color: var(--accent); text-decoration: none; }

.article-tags { display: flex; gap: 8px; margin-bottom: 16px; flex-wrap: wrap; }

.article-header h1 {
  font-size: 1.9rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin-bottom: 16px;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  color: var(--text-muted);
  font-size: 0.85rem;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--border);
}

.article-meta .dot { color: var(--border); }

/* ── Article Body ── */

.article-body { font-size: 1rem; }

.article-body h2 {
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 48px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.article-body h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin: 32px 0 12px;
  color: var(--text);
}

.article-body p { margin-bottom: 20px; }

.article-body ul, .article-body ol {
  margin: 0 0 20px 0;
  padding-left: 24px;
}

.article-body li { margin-bottom: 6px; }

.article-body li ul { margin-top: 6px; margin-bottom: 0; }

.article-body strong { font-weight: 600; color: var(--text); }

.article-body code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
  color: #c7254e;
}

.article-body pre {
  background: #1e1e2e;
  border-radius: var(--radius);
  padding: 20px 24px;
  overflow-x: auto;
  margin: 24px 0;
  font-size: 0.875rem;
  line-height: 1.6;
}

.article-body pre code {
  background: none;
  padding: 0;
  color: #cdd6f4;
  font-size: inherit;
}

.article-body blockquote {
  margin: 28px 0;
  padding: 16px 20px;
  background: var(--accent-light);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.callout {
  margin: 28px 0;
  padding: 20px 24px;
  border-radius: var(--radius);
  border: 1px solid;
  font-size: 0.925rem;
}

.callout-tip {
  background: #f0fdf4;
  border-color: #86efac;
  color: #166534;
}

.callout-warning {
  background: #fffbeb;
  border-color: #fcd34d;
  color: #92400e;
}

.callout-title {
  font-weight: 600;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

/* ── Table ── */

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
  font-size: 0.9rem;
}

.article-body th {
  background: var(--tag-bg);
  padding: 10px 14px;
  text-align: left;
  font-weight: 600;
  border: 1px solid var(--border);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.article-body td {
  padding: 10px 14px;
  border: 1px solid var(--border);
  vertical-align: top;
}

.article-body tr:hover td { background: var(--bg); }

/* ── Phase Steps ── */

.phase-list { list-style: none; padding: 0; margin: 24px 0; }

.phase-item {
  display: flex;
  gap: 16px;
  margin-bottom: 20px;
  padding: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.phase-num {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  background: var(--accent);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  margin-top: 1px;
}

.phase-body h4 { font-size: 0.95rem; font-weight: 600; margin-bottom: 4px; }
.phase-body p { font-size: 0.875rem; color: var(--text-muted); margin: 0; }

/* ── Footer ── */

.site-footer {
  text-align: center;
  padding: 32px 24px;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.825rem;
}

/* ── Download Box ── */

.download-box {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 2rem 0 0.75rem;
}

.download-box-name {
  font-weight: 600;
  font-family: var(--mono);
  font-size: 0.95rem;
}

.download-box-desc {
  font-size: 0.825rem;
  color: var(--text-muted);
  margin-top: 2px;
}

.download-btn {
  display: inline-block;
  padding: 8px 18px;
  background: var(--accent);
  color: #fff !important;
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-weight: 500;
  white-space: nowrap;
  text-decoration: none !important;
  transition: opacity 0.15s;
}

.download-btn:hover { opacity: 0.85; text-decoration: none !important; }

.download-box-actions {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 8px;
}

.download-btn-ghost {
  display: inline-block;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.8rem;
  color: var(--text-muted) !important;
  white-space: nowrap;
  text-decoration: none !important;
  transition: border-color 0.15s, color 0.15s;
}

.download-btn-ghost:hover {
  border-color: var(--accent);
  color: var(--accent) !important;
  text-decoration: none !important;
}

.download-hint {
  font-size: 0.825rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
}

/* ── Responsive ── */

@media (max-width: 600px) {
  .article-header h1 { font-size: 1.5rem; }
  .index-hero h1 { font-size: 1.6rem; }
  .main-content { padding: 32px 20px 64px; }
}