:root {
  --bg: #070a12;
  --bg-soft: #0d1220;
  --fg: #e8ecf4;
  --muted: #9aa4b8;
  --accent: #5bd6ff;
  --accent-soft: rgba(91, 214, 255, 0.15);
  --line: rgba(255, 255, 255, 0.08);
  --max: 1100px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "DM Sans", system-ui, sans-serif;
  background: radial-gradient(1200px 800px at 10% -10%, #132042 0%, transparent 55%),
              radial-gradient(900px 600px at 90% 10%, #1a0f35 0%, transparent 45%),
              var(--bg);
  color: var(--fg);
  line-height: 1.65;
  min-height: 100vh;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 1.5rem; }
header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(12px);
  background: rgba(7, 10, 18, 0.72);
  border-bottom: 1px solid var(--line);
}
header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 4rem;
  gap: 1rem;
  flex-wrap: wrap;
}
.logo {
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--fg);
  display: flex;
  gap: .5rem;
  align-items: baseline;
  text-decoration: none;
}
.logo:hover { text-decoration: none; }
.logo span { color: var(--accent); font-weight: 600; }
nav { display: flex; gap: 1.1rem; font-size: 0.875rem; align-items: center; flex-wrap: wrap; }
nav a { color: var(--muted); text-decoration: none; }
nav a:hover { color: var(--fg); text-decoration: none; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.55rem 1rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.875rem;
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none !important;
}
.btn-primary {
  background: linear-gradient(135deg, #5bd6ff 0%, #7c5dff 100%);
  color: #081018 !important;
}
.btn-primary:hover { filter: brightness(1.06); text-decoration: none !important; }
.hero { padding: 4rem 0 3.5rem; }
.hero h1 {
  font-family: "Instrument Serif", Georgia, serif;
  font-weight: 400;
  font-size: clamp(2.35rem, 5vw, 3.65rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0 0 1.25rem;
}
.hero h1 em {
  font-style: italic;
  color: var(--accent);
  text-shadow: 0 0 40px rgba(91, 214, 255, 0.35);
}
.lead {
  font-size: 1.15rem;
  color: var(--muted);
  max-width: 38rem;
  margin: 0 0 1.75rem;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 1rem; align-items: center; }
.pill {
  display: inline-flex;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  font-size: 0.8125rem;
  font-weight: 500;
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid rgba(91, 214, 255, 0.25);
  margin-bottom: 1.5rem;
}
section { padding: 3rem 0; border-top: 1px solid var(--line); }
section h2 {
  font-size: 1.45rem;
  font-weight: 600;
  margin: 0 0 0.75rem;
}
.sub { margin: 0 0 1.75rem; color: var(--muted); max-width: 44rem; }
.grid3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
}
.card {
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: 1rem;
  padding: 1.35rem;
}
.card h3 { margin: 0 0 .5rem; font-size: 1.0625rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.95rem; line-height: 1.58; }
.tag { font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--accent); margin-bottom: 0.35rem; }
.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1.5rem;
  margin-top: 2.25rem;
}
.stat strong { font-size: 1.75rem; display: block; color: var(--fg); letter-spacing: -0.03em; }
.stat span { font-size: 0.875rem; color: var(--muted); }
.cta {
  text-align: center;
  padding: 3.5rem 1.5rem;
  border-radius: 1.25rem;
  margin: 1rem 0 0;
  background: linear-gradient(165deg, rgba(91, 214, 255, 0.08) 0%, rgba(124, 93, 255, 0.06) 100%);
  border: 1px solid var(--line);
}
.cta h2 { margin-bottom: .75rem; }
footer {
  padding: 2.25rem 0 2rem;
  color: var(--muted);
  font-size: 0.875rem;
  border-top: 1px solid var(--line);
}
footer .wrap { display: flex; flex-wrap: wrap; gap: 1rem 2rem; justify-content: space-between; align-items: center; }

/* Articles & inner pages */
.page-head { padding: 2.5rem 0 1rem; }
.page-head h1 {
  font-family: "Instrument Serif", Georgia, serif;
  font-weight: 400;
  font-size: 2.25rem;
  margin: 0 0 .5rem;
}
.meta { color: var(--muted); font-size: 0.9rem; margin-bottom: 2rem; }
.prose {
  max-width: 44rem;
  color: var(--fg);
  font-size: 1.02rem;
}
.prose p { margin: 0 0 1.1em; color: #c5cedd; }
.prose h2 {
  font-size: 1.2rem;
  margin: 2rem 0 0.75rem;
  color: var(--fg);
  border: none;
  padding: 0;
}
.prose ul { margin: 0 0 1.1em; padding-left: 1.25rem; color: #c5cedd; }
.prose li { margin-bottom: 0.4em; }
.prose strong { color: var(--fg); }
.note-bank {
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-left: 4px solid var(--accent);
  border-radius: 0 .75rem .75rem 0;
  padding: 1.25rem 1.35rem;
  margin: 1.75rem 0;
}
.note-bank h3 { margin: 0 0 .65rem; font-size: 1rem; color: var(--fg); }
.note-bank p { margin: 0 0 .6rem; color: var(--muted); font-size: 0.92rem; }
.note-bank p:last-child { margin-bottom: 0; }
.link-list {
  font-size: 0.88rem;
  word-break: break-all;
  background: rgba(0,0,0,0.25);
  padding: 1rem 1.1rem;
  border-radius: 0.65rem;
  border: 1px solid var(--line);
  margin: .75rem 0 0;
}
.link-list div { margin-bottom: .45rem; }
.link-list div:last-child { margin-bottom: 0; }
.lang-zh {
  margin-top: 1.75rem;
  padding-top: 1.5rem;
  border-top: 1px dashed var(--line);
}
.lang-zh h2 { font-size: 1.1rem; margin-bottom: .5rem; }
.lang-zh p { color: #b8c0d0; font-size: 0.95rem; line-height: 1.75; }