/* OOH Trends - Global Clean Typography & Modern Layout */
:root {
  --bg-primary: #FFFFFF;
  --bg-secondary: #F8FAFC;
  --bg-card: #FFFFFF;
  --text-main: #0F172A;
  --text-muted: #64748B;
  --text-soft: #94A3B8;
  --accent: #2563EB;
  --accent-hover: #1D4ED8;
  --accent-soft: #EFF6FF;
  --border: #E2E8F0;
  --border-focus: #93C5FD;
  --success: #10B981;
  --radius: 10px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-main);
  background-color: var(--bg-secondary);
  color: var(--text-main);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

/* Header & Navigation */
.header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.nav-container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.logo span {
  color: var(--accent);
}

.logo-tag {
  font-size: 0.7rem;
  text-transform: uppercase;
  background: var(--accent-soft);
  color: var(--accent);
  padding: 0.15rem 0.5rem;
  border-radius: 9999px;
  font-weight: 700;
  margin-left: 0.5rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  list-style: none;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-main);
}

.nav-cta {
  background-color: var(--text-main);
  color: #fff !important;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  font-weight: 600;
  transition: background-color 0.15s ease;
}

.nav-cta:hover {
  background-color: var(--accent);
}

/* Container */
.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 3.5rem 1.5rem;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border);
}

.hero-badge {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 0.35rem 0.85rem;
  border-radius: 9999px;
  margin-bottom: 1.25rem;
}

.hero h1 {
  font-size: 2.75rem;
  font-weight: 900;
  letter-spacing: -0.04em;
  line-height: 1.15;
  color: var(--text-main);
  max-width: 850px;
  margin: 0 auto 1.25rem;
}

.hero p {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto 2rem;
}

/* Grids */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.75rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.75rem;
}

/* Cards */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
  display: flex;
  flex-direction: column;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: #CBD5E1;
}

.card-tag {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

.card h2, .card h3 {
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.35;
  margin-bottom: 0.75rem;
}

.card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.card-meta {
  font-size: 0.8rem;
  color: var(--text-soft);
  display: flex;
  align-items: center;
  gap: 0.75rem;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}

/* Article Prose */
.article-container {
  max-width: 780px;
  margin: 0 auto;
  padding: 3rem 1.5rem;
  background: var(--bg-primary);
  border-left: 1px solid var(--border);
  border-right: 1px solid var(--border);
  min-height: 80vh;
}

.article-header {
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 2rem;
}

.article-header h1 {
  font-size: 2.4rem;
  font-weight: 900;
  letter-spacing: -0.035em;
  line-height: 1.2;
  margin-bottom: 1rem;
}

.article-author-strip {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 1.25rem;
}

.author-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: #E2E8F0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #475569;
  font-size: 1.1rem;
  overflow: hidden;
  flex-shrink: 0;
}

.author-avatar img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  display: block;
}

.author-info h4 {
  font-size: 0.95rem;
  font-weight: 700;
}

.author-info p {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.prose {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #1E293B;
}

.prose p {
  margin-bottom: 1.5rem;
}

.prose h2 {
  font-size: 1.65rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  margin: 2.5rem 0 1rem;
  color: var(--text-main);
}

.prose h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin: 2rem 0 0.75rem;
  color: var(--text-main);
}

.prose ul, .prose ol {
  margin: 1rem 0 1.5rem 1.5rem;
}

.prose li {
  margin-bottom: 0.5rem;
}

.prose blockquote {
  border-left: 4px solid var(--accent);
  padding: 0.75rem 1.25rem;
  background: var(--accent-soft);
  margin: 1.75rem 0;
  font-style: italic;
  color: #1E3A8A;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  font-size: 0.95rem;
}

.prose th, .prose td {
  border: 1px solid var(--border);
  padding: 0.75rem 1rem;
  text-align: left;
}

.prose th {
  background: var(--bg-secondary);
  font-weight: 700;
}

.highlight-box {
  background: #F1F5F9;
  border: 1px solid #CBD5E1;
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin: 1.75rem 0;
}

/* Calculator Styles */
.calc-box {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow-sm);
  margin-bottom: 2rem;
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 0.5rem;
}

.form-control {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 1rem;
  font-family: inherit;
  transition: border-color 0.15s;
}

.form-control:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.calc-result-card {
  background: var(--text-main);
  color: #fff;
  border-radius: var(--radius);
  padding: 1.75rem;
  margin-top: 1.5rem;
}

.calc-result-val {
  font-size: 2.25rem;
  font-weight: 800;
  color: #38BDF8;
  margin: 0.25rem 0 1rem;
}

/* Footer */
.footer {
  background: #0F172A;
  color: #94A3B8;
  padding: 4rem 1.5rem 2rem;
  border-top: 1px solid #1E293B;
  margin-top: 4rem;
  font-size: 0.9rem;
}

.footer-grid {
  max-width: 1140px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 2.5rem;
  padding-bottom: 3rem;
  border-bottom: 1px solid #1E293B;
}

.footer h4 {
  color: #FFFFFF;
  font-size: 1rem;
  margin-bottom: 1rem;
}

.footer ul {
  list-style: none;
}

.footer li {
  margin-bottom: 0.6rem;
}

.footer a:hover {
  color: #FFFFFF;
}

.footer-bottom {
  max-width: 1140px;
  margin: 2rem auto 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  .article-header h1 { font-size: 1.85rem; }
  .footer-grid { grid-template-columns: 1fr; gap: 2rem; }
  .nav-links { display: none; }
  .footer-bottom { flex-direction: column; gap: 1rem; text-align: center; }
}