* {
  box-sizing: border-box;
}

:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #2563eb;
  --accent-dark: #1d4ed8;
  --border: #dbe2ea;
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
  --radius: 16px;
  --max: 1100px;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}

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

a:hover {
  color: var(--accent-dark);
}

img {
  max-width: 100%;
  display: block;
}

.container {
  width: min(var(--max), calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  background: linear-gradient(135deg, #0f172a, #1e3a8a);
  color: #fff;
  padding: 24px 0 70px;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}

.logo {
  font-size: 1.2rem;
  font-weight: 700;
  color: #fff;
}

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

.nav a {
  color: rgba(255, 255, 255, 0.9);
  font-size: 0.98rem;
}

.nav a:hover {
  color: #fff;
}

.hero {
  padding-top: 56px;
}

.hero-box {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255,255,255,0.12);
  backdrop-filter: blur(8px);
  border-radius: 24px;
  padding: 36px;
  box-shadow: var(--shadow);
}

.hero-box h1 {
  margin: 0 0 16px;
  font-size: clamp(2rem, 4vw, 3.6rem);
  line-height: 1.1;
}

.hero-box p {
  margin: 0;
  max-width: 820px;
  color: rgba(255,255,255,0.9);
  font-size: 1.05rem;
}

.main-content {
  margin-top: -36px;
  padding-bottom: 60px;
}

.section {
  margin-top: 32px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.intro-card {
  padding: 28px;
}

.intro-card h2 {
  margin-top: 0;
  margin-bottom: 14px;
  font-size: 1.6rem;
}

.posts-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.post-card {
  padding: 22px;
}

.post-card h3 {
  margin-top: 0;
  margin-bottom: 12px;
  font-size: 1.25rem;
  line-height: 1.3;
}

.post-card p {
  margin-bottom: 18px;
  color: var(--muted);
}

.button {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  padding: 10px 16px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.95rem;
}

.button:hover {
  background: var(--accent-dark);
  color: #fff;
}

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 28px;
  align-items: start;
}

.article-card {
  padding: 30px;
}

.article-card h1 {
  margin-top: 0;
  line-height: 1.15;
  font-size: clamp(2rem, 4vw, 3rem);
}

.article-meta {
  color: var(--muted);
  font-size: 0.95rem;
  margin-bottom: 24px;
}

.article-card h2 {
  margin-top: 34px;
  margin-bottom: 10px;
  font-size: 1.5rem;
  line-height: 1.25;
}

.sidebar {
  padding: 22px;
  position: sticky;
  top: 20px;
}

.sidebar h3 {
  margin-top: 0;
}

.sidebar ul {
  padding-left: 18px;
  margin-bottom: 0;
}

.sidebar li {
  margin-bottom: 10px;
}

.cta-box {
  margin-top: 26px;
  padding: 22px;
  border-radius: 16px;
  background: #eff6ff;
  border: 1px solid #bfdbfe;
}

.site-footer {
  background: #0f172a;
  color: rgba(255,255,255,0.86);
  padding: 34px 0;
  margin-top: 50px;
}

.site-footer a {
  color: #93c5fd;
}

.footer-grid {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.muted {
  color: var(--muted);
}

.back-link {
  display: inline-block;
  margin-bottom: 18px;
  font-weight: 700;
}

@media (max-width: 900px) {
  .posts-grid {
    grid-template-columns: 1fr;
  }

  .article-layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }

  .hero-box {
    padding: 26px;
  }

  .article-card {
    padding: 22px;
  }
}