:root {
  --bg: #ffffff;
  --text: #1f2430;
  --muted: #5c6678;
  --primary: #3b6fed;
  --primary-dark: #2a55c0;
  --border: #e6e9f0;
  --card: #f7f9fc;
  --accent: #eaf0ff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 17px;
}

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

.container { max-width: 820px; margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  border-bottom: 1px solid var(--border);
  background: #fff;
  position: sticky;
  top: 0;
  z-index: 10;
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo { font-size: 20px; font-weight: 800; color: var(--text); }
.logo span { color: var(--primary); }
.nav a { margin-left: 22px; color: var(--muted); font-weight: 600; font-size: 15px; }
.nav a:hover { color: var(--primary); text-decoration: none; }

/* Hero */
.hero {
  background: linear-gradient(180deg, var(--accent), #fff);
  padding: 56px 0 40px;
  text-align: center;
  border-bottom: 1px solid var(--border);
}
.hero h1 { font-size: 34px; margin: 0 0 14px; line-height: 1.25; }
.hero p { font-size: 18px; color: var(--muted); max-width: 620px; margin: 0 auto; }

/* Ad slot */
.ad-slot {
  margin: 28px auto;
  padding: 14px;
  text-align: center;
  background: var(--card);
  border: 1px dashed var(--border);
  border-radius: 10px;
  color: #aeb6c4;
  font-size: 13px;
  min-height: 90px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Article cards */
.section-title { font-size: 22px; margin: 36px 0 18px; }
.cards { display: grid; grid-template-columns: 1fr; gap: 18px; }
.card {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px;
  background: #fff;
  transition: box-shadow .15s ease, transform .15s ease;
}
.card:hover { box-shadow: 0 6px 24px rgba(31,36,48,.08); transform: translateY(-2px); }
.card h3 { margin: 0 0 8px; font-size: 20px; }
.card h3 a { color: var(--text); }
.card .meta { color: var(--muted); font-size: 14px; margin-bottom: 10px; }
.card p { margin: 0 0 14px; color: var(--muted); }
.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  padding: 9px 18px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 15px;
}
.btn:hover { background: var(--primary-dark); text-decoration: none; }

/* Article page */
.article { padding: 40px 0 20px; }
.article h1 { font-size: 30px; line-height: 1.3; margin: 0 0 12px; }
.article .meta { color: var(--muted); font-size: 15px; margin-bottom: 24px; }
.article h2 { font-size: 23px; margin: 32px 0 12px; }
.article h3 { font-size: 19px; margin: 24px 0 8px; }
.article p { margin: 0 0 18px; }
.article ul, .article ol { margin: 0 0 18px; padding-left: 24px; }
.article li { margin-bottom: 8px; }
.article blockquote {
  margin: 24px 0;
  padding: 14px 20px;
  border-left: 4px solid var(--primary);
  background: var(--card);
  color: var(--muted);
  border-radius: 0 8px 8px 0;
}
.back-link { display: inline-block; margin: 20px 0; color: var(--muted); font-weight: 600; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 48px;
  padding: 30px 0;
  color: var(--muted);
  font-size: 14px;
  text-align: center;
}
.site-footer a { color: var(--muted); }

@media (max-width: 600px) {
  .hero h1 { font-size: 26px; }
  .nav a { margin-left: 14px; font-size: 14px; }
  body { font-size: 16px; }
}