/* ============================================
   mobidays-blog-cb1259.netlify.app — Blog Stylesheet
   모비데이즈 콘텐츠 허브 (서브도메인)
   Mobile-first responsive design
   ============================================ */

/* ---------- CSS Variables ---------- */
:root {
  --color-primary: #1B365D;
  --color-accent: #2563EB;
  --color-accent-dark: #1D4ED8;
  --color-secondary: #0EA5E9;
  --color-white: #FFFFFF;
  --color-gray-50: #F9FAFB;
  --color-gray-100: #F3F4F6;
  --color-gray-200: #E5E7EB;
  --color-gray-300: #D1D5DB;
  --color-gray-400: #9CA3AF;
  --color-gray-500: #6B7280;
  --color-gray-600: #4B5563;
  --color-gray-700: #374151;
  --color-gray-800: #1F2937;
  --color-gray-900: #111827;
  --color-text: #1F2937;
  --color-text-light: #6B7280;
  --color-border: #E5E7EB;

  --font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui,
    'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;

  --max-width: 1200px;
  --header-height: 64px;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 9999px;

  --transition: 0.3s ease;
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-family);
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-text);
  background-color: var(--color-white);
  -webkit-font-smoothing: antialiased;
  word-break: keep-all;
  overflow-wrap: break-word;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--color-accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-accent-dark); }
ul, ol { list-style: none; }

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 { font-weight: 700; line-height: 1.3; color: var(--color-gray-900); }
h1 { font-size: 2.25rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.375rem; }

/* ---------- Layout ---------- */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 1.5rem; }

/* ---------- Header ---------- */
.header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  height: var(--header-height);
  background: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--transition);
}
.header.scrolled { box-shadow: var(--shadow-md); }
.header .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 100%;
}
.header-logo {
  display: flex; align-items: center; gap: 0.5rem;
  text-decoration: none; color: var(--color-primary);
  font-size: 1.25rem; font-weight: 800; letter-spacing: -0.02em;
}
.header-logo .blog-label {
  font-size: 0.75rem; font-weight: 600;
  background: var(--color-accent); color: white;
  padding: 0.125rem 0.5rem; border-radius: var(--radius-full);
  margin-left: 0.25rem;
}

/* Desktop Nav */
.nav { display: flex; align-items: center; gap: 2rem; }
.nav a {
  font-size: 0.9375rem; font-weight: 500;
  color: var(--color-gray-600); text-decoration: none;
  transition: color var(--transition);
}
.nav a:hover, .nav a.active { color: var(--color-accent); }
.nav .btn-contact {
  background: var(--color-accent); color: white;
  padding: 0.5rem 1.25rem; border-radius: var(--radius-full);
  font-weight: 600; font-size: 0.875rem;
}
.nav .btn-contact:hover { background: var(--color-accent-dark); color: white; }

/* Mobile Menu */
.mobile-toggle { display: none; background: none; border: none; cursor: pointer; padding: 0.5rem; }
.mobile-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--color-gray-700); margin: 5px 0;
  transition: var(--transition);
}
.mobile-menu {
  display: none; position: fixed;
  top: var(--header-height); left: 0; right: 0; bottom: 0;
  background: var(--color-white); z-index: 999;
  padding: 2rem 1.5rem; flex-direction: column; gap: 0;
}
.mobile-menu.open { display: flex; }
.mobile-menu a {
  display: block; padding: 1rem 0;
  font-size: 1.125rem; font-weight: 500;
  color: var(--color-gray-700); border-bottom: 1px solid var(--color-gray-100);
}

/* ---------- Blog Hub ---------- */
.blog-hub-hero {
  padding: 6rem 0 3rem;
  background: linear-gradient(135deg, var(--color-primary) 0%, #2D4A7A 100%);
  color: var(--color-white); text-align: center;
}
.blog-hub-hero h1 { font-size: 2.5rem; margin-bottom: 1rem; }
.blog-hub-hero p { font-size: 1.125rem; opacity: 0.9; max-width: 640px; margin: 0 auto; }

.blog-filter {
  display: flex; justify-content: center; gap: 0.75rem;
  padding: 2rem 0 0; flex-wrap: wrap;
}
.blog-filter button {
  padding: 0.5rem 1.25rem; border-radius: var(--radius-full);
  border: 1px solid var(--color-border); background: var(--color-white);
  font-size: 0.875rem; font-weight: 500; cursor: pointer;
  transition: var(--transition); color: var(--color-gray-600);
}
.blog-filter button.active, .blog-filter button:hover {
  background: var(--color-accent); color: white; border-color: var(--color-accent);
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 2rem; padding: 3rem 0 4rem;
}
.blog-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden; transition: var(--transition);
  text-decoration: none; color: inherit;
  display: flex; flex-direction: column;
}
.blog-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-accent);
}
.blog-card-body { padding: 1.5rem; flex: 1; display: flex; flex-direction: column; }
.blog-card-badge {
  display: inline-block;
  padding: 0.25rem 0.75rem; border-radius: var(--radius-full);
  font-size: 0.75rem; font-weight: 600;
  margin-bottom: 0.75rem; width: fit-content;
}
.badge-encyclopedia { background: #DBEAFE; color: #1E40AF; }
.badge-guide { background: #D1FAE5; color: #065F46; }
.badge-qa { background: #FEF3C7; color: #92400E; }

.blog-card-title {
  font-size: 1.25rem; font-weight: 700;
  color: var(--color-gray-900); margin-bottom: 0.75rem; line-height: 1.4;
}
.blog-card-excerpt {
  font-size: 0.9375rem; color: var(--color-gray-600);
  line-height: 1.6; flex: 1; margin-bottom: 1rem;
}
.blog-card-meta {
  font-size: 0.8125rem; color: var(--color-gray-400);
  display: flex; justify-content: space-between; align-items: center;
  padding-top: 1rem; border-top: 1px solid var(--color-gray-100);
}
.blog-card-readmore { color: var(--color-accent); font-weight: 600; font-size: 0.875rem; }

/* ---------- Blog Article ---------- */
.blog-article-hero {
  padding: 6rem 0 2.5rem;
  background: linear-gradient(135deg, var(--color-primary) 0%, #2D4A7A 100%);
  color: var(--color-white);
}
.blog-article-hero .container { max-width: 800px; }
.blog-article-hero .badge {
  display: inline-block; padding: 0.25rem 0.75rem;
  border-radius: var(--radius-full); font-size: 0.75rem; font-weight: 600;
  margin-bottom: 1rem; background: rgba(255,255,255,0.2);
}
.blog-article-hero h1 { font-size: 2.25rem; line-height: 1.3; margin-bottom: 1rem; }
.blog-article-hero .meta { font-size: 0.9375rem; opacity: 0.8; }

.blog-article-content {
  max-width: 800px; margin: 0 auto;
  padding: 3rem 1.5rem 4rem;
  font-size: 1.0625rem; line-height: 1.8;
  color: var(--color-text);
}
.blog-article-content h2 {
  font-size: 1.5rem; font-weight: 700;
  color: var(--color-primary); margin: 2.5rem 0 1rem;
  padding-bottom: 0.5rem; border-bottom: 2px solid var(--color-accent);
}
.blog-article-content h3 {
  font-size: 1.25rem; font-weight: 600;
  color: var(--color-gray-800); margin: 2rem 0 0.75rem;
}
.blog-article-content p { margin-bottom: 1.25rem; }
.blog-article-content ul, .blog-article-content ol { margin: 1rem 0 1.5rem 1.5rem; }
.blog-article-content ul { list-style: disc; }
.blog-article-content ol { list-style: decimal; }
.blog-article-content li { margin-bottom: 0.5rem; }
.blog-article-content strong { color: var(--color-gray-900); }

.blog-article-content .highlight-box {
  background: linear-gradient(135deg, #EFF6FF, #F0F9FF);
  border-left: 4px solid var(--color-accent);
  padding: 1.25rem 1.5rem;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin: 1.5rem 0; font-size: 1rem;
}
.blog-article-content .highlight-box strong { color: var(--color-accent); }

.blog-article-content .summary-box {
  background: var(--color-gray-50);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem; margin: 1.5rem 0;
}
.blog-article-content .summary-box h4 {
  font-size: 1rem; font-weight: 700;
  margin-bottom: 0.75rem; color: var(--color-primary);
}

.blog-article-content table {
  width: 100%; border-collapse: collapse;
  margin: 1.5rem 0; font-size: 0.9375rem;
}
.blog-article-content th {
  background: var(--color-primary); color: var(--color-white);
  padding: 0.75rem 1rem; text-align: left; font-weight: 600;
}
.blog-article-content td {
  padding: 0.75rem 1rem; border-bottom: 1px solid var(--color-border);
}
.blog-article-content tr:nth-child(even) td { background: var(--color-gray-50); }

.blog-article-content .faq-item {
  margin-bottom: 1.5rem; padding: 1.25rem;
  background: var(--color-gray-50); border-radius: var(--radius-md);
  border-left: 4px solid var(--color-accent);
}
.blog-article-content .faq-item .question {
  font-weight: 700; color: var(--color-primary);
  margin-bottom: 0.5rem; font-size: 1.0625rem;
}
.blog-article-content .faq-item .answer { color: var(--color-gray-700); }

/* ---------- Blog Navigation & CTA ---------- */
.blog-nav-bottom {
  max-width: 800px; margin: 0 auto;
  padding: 2rem 1.5rem 3rem;
  display: flex; justify-content: space-between;
  gap: 1rem; flex-wrap: wrap;
}
.blog-nav-bottom a {
  padding: 0.75rem 1.5rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md); text-decoration: none;
  color: var(--color-text); font-size: 0.875rem;
  transition: var(--transition);
}
.blog-nav-bottom a:hover { border-color: var(--color-accent); color: var(--color-accent); }

.blog-cta {
  background: linear-gradient(135deg, var(--color-primary) 0%, #2D4A7A 100%);
  padding: 3rem 1.5rem; text-align: center; color: var(--color-white);
}
.blog-cta h3 { font-size: 1.5rem; margin-bottom: 0.75rem; }
.blog-cta p { opacity: 0.9; margin-bottom: 1.5rem; max-width: 500px; margin-left: auto; margin-right: auto; }
.blog-cta .btn {
  display: inline-block; padding: 0.875rem 2rem;
  background: var(--color-accent); color: white;
  border-radius: var(--radius-full); font-weight: 600;
  font-size: 1rem; transition: var(--transition);
}
.blog-cta .btn:hover { background: var(--color-accent-dark); color: white; }

/* ---------- Internal Link Blocks (3-Layer) ---------- */
.related-links {
  max-width: 800px; margin: 0 auto;
  padding: 0 1.5rem 2rem;
}
.related-links h3 {
  font-size: 1.125rem; font-weight: 700;
  color: var(--color-primary); margin-bottom: 1rem;
}
.related-links-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 0.75rem;
}
.related-link-card {
  display: flex; align-items: center; gap: 0.75rem;
  padding: 0.875rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md); text-decoration: none;
  color: var(--color-text); font-size: 0.875rem;
  transition: var(--transition);
}
.related-link-card:hover {
  border-color: var(--color-accent); color: var(--color-accent);
  background: var(--color-gray-50);
}
.related-link-card .layer-badge {
  font-size: 0.6875rem; font-weight: 700;
  padding: 0.125rem 0.375rem; border-radius: var(--radius-sm);
  flex-shrink: 0;
}
.layer-badge.l1 { background: #DBEAFE; color: #1E40AF; }
.layer-badge.l2 { background: #D1FAE5; color: #065F46; }
.layer-badge.l3 { background: #FEF3C7; color: #92400E; }

/* ---------- Entity Mini Box ---------- */
.entity-box {
  background: var(--color-gray-50);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem; margin: 2rem 0;
}
.entity-box h3 {
  font-size: 1.125rem; font-weight: 700;
  color: var(--color-primary); margin-bottom: 0.75rem;
}
.entity-box p { font-size: 0.9375rem; color: var(--color-gray-600); line-height: 1.7; }
.entity-stats {
  display: flex; flex-wrap: wrap; gap: 1rem;
  margin-top: 1rem; padding-top: 1rem;
  border-top: 1px solid var(--color-border);
}
.entity-stat {
  font-size: 0.8125rem; color: var(--color-gray-500);
  padding: 0.25rem 0.75rem;
  background: var(--color-white); border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
}

/* ---------- Footer ---------- */
.footer {
  background: var(--color-gray-900); color: var(--color-gray-400);
  padding: 3rem 0 2rem; font-size: 0.875rem;
}
.footer-content {
  display: flex; justify-content: space-between;
  flex-wrap: wrap; gap: 2rem;
}
.footer-info h4 {
  color: var(--color-white); font-size: 1rem;
  margin-bottom: 0.75rem;
}
.footer-info p { margin-bottom: 0.25rem; line-height: 1.6; }
.footer-links { display: flex; gap: 2rem; }
.footer-links a { color: var(--color-gray-400); font-size: 0.875rem; }
.footer-links a:hover { color: var(--color-white); }
.footer-bottom {
  margin-top: 2rem; padding-top: 1.5rem;
  border-top: 1px solid var(--color-gray-700);
  text-align: center; font-size: 0.8125rem;
  color: var(--color-gray-500);
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
  .header-logo { font-size: 1.125rem; }
  .nav { display: none; }
  .mobile-toggle { display: block; }
  .blog-hub-hero { padding: 5rem 0 2rem; }
  .blog-hub-hero h1 { font-size: 1.75rem; }
  .blog-grid { grid-template-columns: 1fr; gap: 1.5rem; }
  .blog-article-hero { padding: 5rem 0 2rem; }
  .blog-article-hero h1 { font-size: 1.625rem; }
  .blog-article-content { padding: 2rem 1rem 3rem; font-size: 1rem; }
  .blog-article-content h2 { font-size: 1.3125rem; }
  .blog-nav-bottom { flex-direction: column; }
  .blog-nav-bottom a { text-align: center; }
  .footer-content { flex-direction: column; }
  .related-links-grid { grid-template-columns: 1fr; }
  .entity-stats { flex-direction: column; gap: 0.5rem; }
}