:root {
  --bg: #F6F8FA;
  --panel: #FFFFFF;
  --line: #E4E9EE;
  --ink: #10151C;
  --ink-dim: #5B6572;
  --signal: #2F6FED;
  --signal-soft: #EAF1FE;
  --coral: #FF6B4A;
  --coral-soft: #FFEDE8;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  padding-bottom: 100px;
}

a { color: inherit; text-decoration: none; }

/* ---------- Nav ---------- */
nav {
  max-width: 1100px;
  margin: 0 auto;
  padding: 28px 24px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo { font-weight: 800; font-size: 18px; letter-spacing: -0.01em; }
.logo span { color: var(--signal); }

.nav-links { display: flex; gap: 28px; font-size: 14px; color: var(--ink-dim); }
.nav-links a:hover { color: var(--signal); }

@media (max-width: 640px) {
  .nav-links { display: none; }
}

/* ---------- Eyebrow ---------- */
.eyebrow {
  font-family: 'Courier New', monospace;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--signal);
  text-transform: uppercase;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 22px;
  background: var(--signal-soft);
  padding: 6px 12px;
  border-radius: 100px;
}

.eyebrow::before {
  content: '';
  width: 7px;
  height: 7px;
  background: var(--signal);
  border-radius: 50%;
  animation: pulse 1.8s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

/* ---------- Header (index page) ---------- */
header.hero {
  padding: 56px 24px 44px;
  max-width: 1100px;
  margin: 0 auto;
}

header.hero h1 {
  font-size: clamp(32px, 5vw, 50px);
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: -0.02em;
  max-width: 760px;
}

header.hero h1 span { color: var(--signal); }

header.hero p {
  margin-top: 18px;
  color: var(--ink-dim);
  font-size: 17px;
  max-width: 560px;
  line-height: 1.55;
}

/* ---------- Grid / cards (index page) ---------- */
main { max-width: 1100px; margin: 0 auto; padding: 0 24px; }

.grid-label {
  font-family: 'Courier New', monospace;
  font-size: 12px;
  color: var(--ink-dim);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 20px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.grid { display: flex; flex-wrap: wrap; gap: 18px; }

.card {
  width: calc(50% - 9px);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 30px 28px;
  box-shadow: 0 1px 2px rgba(16, 21, 28, 0.03);
  transition: box-shadow 0.2s ease, transform 0.2s ease, border-color 0.2s ease;
  cursor: pointer;
  display: flex;
  flex-direction: column;
}

@media (max-width: 640px) {
  .card { width: 100%; }
}

.card:hover {
  box-shadow: 0 12px 24px rgba(16, 21, 28, 0.08);
  transform: translateY(-2px);
  border-color: var(--signal);
}

.card:hover .arrow { background: var(--signal); color: #fff; }

.card-tag {
  display: inline-block;
  width: fit-content;
  font-family: 'Courier New', monospace;
  font-size: 11px;
  color: var(--signal);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 16px;
  background: var(--signal-soft);
  padding: 5px 10px;
  border-radius: 6px;
}

.card-tag.alt { color: var(--coral); background: var(--coral-soft); }

.card h3 { font-size: 20px; font-weight: 700; line-height: 1.35; margin-bottom: 10px; color: var(--ink); }
.card p { font-size: 14.5px; color: var(--ink-dim); line-height: 1.55; flex-grow: 1; }

.card-footer { display: flex; justify-content: space-between; align-items: center; margin-top: 20px; }
.read-time { font-family: 'Courier New', monospace; font-size: 11px; color: var(--ink-dim); }

.arrow {
  width: 28px; height: 28px; border-radius: 50%;
  background: var(--bg); color: var(--ink-dim);
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; transition: all 0.2s ease;
}

/* ---------- Breadcrumb ---------- */
.breadcrumb {
  max-width: 760px;
  margin: 0 auto;
  padding: 32px 24px 0;
  font-size: 13px;
  color: var(--ink-dim);
}

.breadcrumb a:hover { color: var(--signal); }

/* ---------- Article ---------- */
.article-header {
  max-width: 760px;
  margin: 0 auto;
  padding: 20px 24px 40px;
  border-bottom: 1px solid var(--line);
}

.article-header .card-tag { margin-bottom: 18px; }

.article-header h1 {
  font-size: clamp(28px, 4.5vw, 42px);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.article-meta {
  font-family: 'Courier New', monospace;
  font-size: 12px;
  color: var(--ink-dim);
  display: flex;
  gap: 16px;
}

.article-body {
  max-width: 760px;
  margin: 0 auto;
  padding: 40px 24px 0;
  font-size: 17px;
  line-height: 1.75;
  color: #26303B;
}

.article-body p { margin-bottom: 22px; }

.article-body h2 {
  font-size: 25px;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 44px 0 18px;
  color: var(--ink);
}

.article-body h3 {
  font-size: 19px;
  font-weight: 700;
  margin: 30px 0 12px;
  color: var(--ink);
}

.article-body ul, .article-body ol {
  margin: 0 0 22px 22px;
}

.article-body li { margin-bottom: 10px; }

.article-body strong { color: var(--ink); }

.callout {
  background: var(--signal-soft);
  border-left: 3px solid var(--signal);
  border-radius: 8px;
  padding: 18px 22px;
  margin: 28px 0;
  font-size: 15.5px;
  color: #1B3A75;
}

.callout.warn {
  background: var(--coral-soft);
  border-left-color: var(--coral);
  color: #7A2E1C;
}

.callout b { display: block; margin-bottom: 4px; font-size: 13px; text-transform: uppercase; letter-spacing: 0.04em; font-family: 'Courier New', monospace; }

/* ---------- FAQ ---------- */
.faq-item {
  border-top: 1px solid var(--line);
  padding: 20px 0;
}

.faq-item h3 { margin: 0 0 8px; font-size: 16.5px; }
.faq-item p { margin: 0; font-size: 15px; color: var(--ink-dim); }

/* ---------- Related ---------- */
.related {
  max-width: 760px;
  margin: 56px auto 0;
  padding: 40px 24px 0;
  border-top: 1px solid var(--line);
}

.related h2 { font-size: 20px; margin-bottom: 20px; }

.related-grid { display: flex; flex-wrap: wrap; gap: 14px; }

.related-card {
  flex: 1 1 220px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 18px 20px;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.related-card:hover { border-color: var(--signal); transform: translateY(-2px); }
.related-card .card-tag { margin-bottom: 10px; }
.related-card h4 { font-size: 15px; font-weight: 600; line-height: 1.4; }

/* ---------- Footer ---------- */
footer {
  max-width: 1100px;
  margin: 64px auto 0;
  padding: 28px 24px 0;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  color: var(--ink-dim);
}

footer.article-footer { max-width: 760px; }

@media (max-width: 640px) {
  footer { flex-direction: column; gap: 10px; text-align: center; }
}