/* ============================================================
   TechPulse Blog — Mobile-first, fast-loading, AdSense-friendly
   ============================================================ */

:root {
  --color-bg: #ffffff;
  --color-text: #1a1a2e;
  --color-text-muted: #555;
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-accent: #f59e0b;
  --color-border: #e5e7eb;
  --color-card: #f9fafb;
  --color-code-bg: #f3f4f6;
  --max-width: 1200px;
  --content-width: 760px;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-heading: "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, sans-serif;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --radius: 8px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0f172a;
    --color-text: #f1f5f9;
    --color-text-muted: #94a3b8;
    --color-border: #1e293b;
    --color-card: #1e293b;
    --color-code-bg: #1e293b;
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--color-primary); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--color-primary-dark); text-decoration: underline; }

.site-header {
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  position: sticky; top: 0; z-index: 100;
  backdrop-filter: blur(10px);
}
.header-inner {
  max-width: var(--max-width); margin: 0 auto; padding: 16px 20px;
  display: flex; justify-content: space-between; align-items: center; gap: 20px;
}
.logo { font-size: 24px; font-weight: 800; color: var(--color-text); display: flex; align-items: center; gap: 8px; }
.logo-dot { color: var(--color-primary); }
.nav { display: flex; gap: 24px; align-items: center; }
.nav a { color: var(--color-text); font-weight: 500; font-size: 15px; }
.nav a:hover { color: var(--color-primary); text-decoration: none; }
.search-box {
  padding: 8px 14px; border: 1px solid var(--color-border); border-radius: var(--radius);
  background: var(--color-card); color: var(--color-text); font-size: 14px; width: 220px;
  transition: border-color 0.2s, width 0.2s;
}
.search-box:focus { outline: none; border-color: var(--color-primary); }
@media (max-width: 720px) {
  .nav { display: none; }
  .search-box { width: 140px; }
}

.hero { text-align: center; padding: 60px 20px 40px; background: linear-gradient(135deg, var(--color-card) 0%, var(--color-bg) 100%); }
.hero h1 { font-size: clamp(28px, 5vw, 44px); font-weight: 800; margin-bottom: 16px; line-height: 1.2; }
.hero p { font-size: 18px; color: var(--color-text-muted); max-width: 640px; margin: 0 auto; }

.container { max-width: var(--max-width); margin: 0 auto; padding: 40px 20px; }
.layout { display: grid; grid-template-columns: 1fr 300px; gap: 40px; }
@media (max-width: 960px) { .layout { grid-template-columns: 1fr; } }

.post-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px; }
.post-card {
  background: var(--color-card); border: 1px solid var(--color-border); border-radius: var(--radius);
  padding: 24px; transition: transform 0.2s, box-shadow 0.2s;
}
.post-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.post-card .category {
  display: inline-block; background: var(--color-primary); color: white;
  font-size: 11px; font-weight: 600; text-transform: uppercase;
  padding: 4px 10px; border-radius: 4px; margin-bottom: 12px; letter-spacing: 0.5px;
}
.post-card h2 { font-size: 20px; font-weight: 700; margin-bottom: 10px; line-height: 1.3; }
.post-card h2 a { color: var(--color-text); }
.post-card h2 a:hover { color: var(--color-primary); text-decoration: none; }
.post-card .excerpt { color: var(--color-text-muted); font-size: 15px; margin-bottom: 16px; }
.post-card .meta { font-size: 13px; color: var(--color-text-muted); display: flex; justify-content: space-between; align-items: center; }
.read-more { font-weight: 600; font-size: 14px; }

.sidebar { display: flex; flex-direction: column; gap: 24px; }
.sidebar-widget { background: var(--color-card); border: 1px solid var(--color-border); border-radius: var(--radius); padding: 20px; }
.sidebar-widget h3 { font-size: 16px; font-weight: 700; margin-bottom: 14px; text-transform: uppercase; letter-spacing: 0.5px; color: var(--color-text-muted); }
.sidebar-widget ul { list-style: none; }
.sidebar-widget li { padding: 8px 0; border-bottom: 1px solid var(--color-border); }
.sidebar-widget li:last-child { border-bottom: none; }
.sidebar-widget a { color: var(--color-text); font-size: 14px; }

.article { max-width: var(--content-width); margin: 0 auto; padding: 40px 20px; }
.article-header { margin-bottom: 40px; text-align: center; }
.article-header .category { display: inline-block; background: var(--color-primary); color: white; font-size: 12px; font-weight: 600; text-transform: uppercase; padding: 5px 12px; border-radius: 4px; margin-bottom: 16px; letter-spacing: 0.5px; }
.article-header h1 { font-size: clamp(28px, 4vw, 40px); font-weight: 800; line-height: 1.2; margin-bottom: 16px; }
.article-meta { font-size: 14px; color: var(--color-text-muted); display: flex; justify-content: center; gap: 16px; flex-wrap: wrap; }

.article-content { font-size: 18px; line-height: 1.8; }
.article-content h2 { font-size: 28px; font-weight: 700; margin: 40px 0 16px; line-height: 1.3; }
.article-content h3 { font-size: 22px; font-weight: 700; margin: 32px 0 12px; line-height: 1.4; }
.article-content p { margin-bottom: 20px; }
.article-content ul, .article-content ol { margin: 0 0 20px 24px; }
.article-content li { margin-bottom: 8px; }
.article-content blockquote { border-left: 4px solid var(--color-primary); padding: 12px 20px; margin: 24px 0; background: var(--color-card); border-radius: 0 var(--radius) var(--radius) 0; font-style: italic; color: var(--color-text-muted); }
.article-content code { background: var(--color-code-bg); padding: 2px 6px; border-radius: 4px; font-family: "Courier New", monospace; font-size: 0.9em; }
.article-content pre { background: var(--color-code-bg); padding: 16px; border-radius: var(--radius); overflow-x: auto; margin: 24px 0; }
.article-content pre code { background: none; padding: 0; }
.article-content a { font-weight: 500; }

.article-footer { margin-top: 60px; padding-top: 30px; border-top: 1px solid var(--color-border); }
.tags { display: flex; flex-wrap: wrap; gap: 8px; }
.tag { background: var(--color-card); padding: 6px 12px; border-radius: 20px; font-size: 13px; color: var(--color-text-muted); border: 1px solid var(--color-border); }

.ad-slot {
  margin: 32px auto; text-align: center; min-height: 90px;
  background: var(--color-card); border: 1px dashed var(--color-border); border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  color: var(--color-text-muted); font-size: 13px; padding: 20px;
}
.ad-slot.in-article { margin: 40px 0; min-height: 250px; }

.site-footer { border-top: 1px solid var(--color-border); background: var(--color-card); padding: 40px 20px 20px; margin-top: 60px; }
.footer-inner { max-width: var(--max-width); margin: 0 auto; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; }
@media (max-width: 720px) { .footer-inner { grid-template-columns: 1fr; gap: 24px; } }
.footer-col h4 { font-size: 14px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.5px; margin-bottom: 12px; color: var(--color-text); }
.footer-col p, .footer-col a { font-size: 14px; color: var(--color-text-muted); }
.footer-col ul { list-style: none; }
.footer-col li { padding: 4px 0; }
.footer-bottom { text-align: center; margin-top: 30px; padding-top: 20px; border-top: 1px solid var(--color-border); font-size: 13px; color: var(--color-text-muted); }

.pagination { display: flex; justify-content: center; gap: 8px; margin: 40px 0; }
.pagination a, .pagination span { padding: 8px 14px; border: 1px solid var(--color-border); border-radius: var(--radius); color: var(--color-text); font-size: 14px; }
.pagination a:hover { background: var(--color-primary); color: white; border-color: var(--color-primary); text-decoration: none; }
.pagination .current { background: var(--color-primary); color: white; border-color: var(--color-primary); }

.text-center { text-align: center; }
.empty-state { text-align: center; padding: 60px 20px; color: var(--color-text-muted); }