:root {
  --sky: rgb(124, 188, 238);
  --sky-deep: #4189cc;
  --sky-tint: rgba(124, 188, 238, 0.08);
  --sky-tint-strong: rgba(124, 188, 238, 0.15);
  --dark: #1a2332;
  --text: #1a2332;
  --text-muted: #6b7280;
  --text-subtle: #9ca3af;
  --border: #ececec;
  --bg: #fafafa;
}

* { box-sizing: border-box; }

body {
  background: var(--bg);
  margin: 0;
  padding-top: 60px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ═══════════════════════════════════
   NAV — identical to landing topbar
   ═══════════════════════════════════ */
.topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 clamp(20px, 3vw, 60px);
  height: 60px;
  background: var(--sky);
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
  box-shadow: darkgray 0px 2px 5px;
}

.topbar-logo {
  font-family: "Bagel Fat One", system-ui, sans-serif;
  font-weight: 200;
  font-size: 1.4rem;
  color: #fff;
  text-decoration: none;
  letter-spacing: 0.03em;
}

.topbar-nav {
  list-style: none;
  display: flex;
  gap: 32px;
  margin: 0;
  padding: 0;
}

.topbar-nav a {
  font-family: 'DM Sans', sans-serif;
  font-size: 1.0rem;
  font-weight: 900;
  color: #fff;
  text-decoration: none;
  text-shadow: darkgrey 0.5px 0.5px 2px;
  opacity: 0.85;
  transition: opacity 0.2s ease;
}
.topbar-nav a:hover { opacity: 1; }

.hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  width: 28px;
  height: 20px;
  position: relative;
  z-index: 200;
}
.hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  position: absolute;
  left: 0;
  transition: all 0.3s ease;
}
.hamburger span:nth-child(1) { top: 0; }
.hamburger span:nth-child(2) { top: 9px; }
.hamburger span:nth-child(3) { top: 18px; }
.hamburger.open span:nth-child(1) { top: 9px; transform: rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { top: 9px; transform: rotate(-45deg); }

.mobile-nav {
  position: fixed;
  inset: 0;
  z-index: 150;
  background: rgba(26, 35, 50, 0.96);
  backdrop-filter: blur(20px);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.35s ease;
}
.mobile-nav.open { opacity: 1; pointer-events: auto; }
.mobile-nav ul { list-style: none; text-align: center; margin: 0; padding: 0; }
.mobile-nav li { margin-bottom: 28px; }
.mobile-nav a {
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 1.6rem;
  color: #fff;
  text-decoration: none;
  opacity: 0.85;
  transition: opacity 0.2s;
}
.mobile-nav a:hover { opacity: 1; }
body.nav-open { overflow: hidden; }

@media (max-width: 640px) {
  .topbar-nav { display: none; }
  .hamburger { display: block; }
}

/* ═══════════════════════════════════
   ARTICLE BODY
   ═══════════════════════════════════ */
.article-body {
  max-width: 680px;
  margin: 0 auto;
  padding: 80px clamp(20px, 4vw, 32px) 120px;
  color: var(--text);
  font-family: 'DM Sans', -apple-system, sans-serif;
  font-size: 1.125rem;
  line-height: 1.75;
}

.article-body h1 {
  font-family: "Bagel Fat One", system-ui, sans-serif;
  font-weight: 400;
  font-size: clamp(2.25rem, 5vw, 3.25rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
  margin: 0 0 16px;
  color: var(--dark);
}

.article-meta {
  color: var(--text-subtle);
  font-size: 0.875rem;
  font-weight: 500;
  margin: 0 0 56px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--border);
  letter-spacing: 0.02em;
}

.article-body h2 {
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 1.625rem;
  line-height: 1.25;
  margin: 64px 0 20px;
  color: var(--dark);
  letter-spacing: -0.01em;
}

.article-body h3 {
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  font-size: 1.25rem;
  margin: 40px 0 14px;
  color: var(--dark);
}

.article-body p {
  margin: 0 0 24px;
}

.article-body strong {
  font-weight: 700;
  color: var(--dark);
}

.article-body a {
  color: var(--sky-deep);
  text-decoration: underline;
  text-decoration-thickness: 1.5px;
  text-underline-offset: 3px;
  transition: color 0.15s;
}

.article-body a:hover {
  color: var(--dark);
  text-decoration-color: var(--sky);
}

/* Code */
.article-body code {
  background: var(--sky-tint-strong);
  color: var(--sky-deep);
  padding: 2px 7px;
  border-radius: 5px;
  font-family: 'DM Mono', 'SF Mono', monospace;
  font-size: 0.875em;
  font-weight: 500;
}

.article-body pre {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px 26px;
  overflow-x: auto;
  margin: 28px 0;
  font-size: 0.9375rem;
  line-height: 1.7;
}

.article-body pre code {
  background: none;
  padding: 0;
  color: var(--text);
  font-size: inherit;
  font-weight: 400;
}

/* Lists */
.article-body ol,
.article-body ul {
  padding-left: 1.5rem;
  margin: 0 0 24px;
}

.article-body li {
  margin-bottom: 10px;
}

.article-body li::marker {
  color: var(--sky-deep);
  font-weight: 700;
}

/* Blockquotes */
.article-body blockquote {
  border-left: 3px solid var(--sky);
  padding: 4px 0 4px 24px;
  margin: 28px 0;
  color: var(--text-muted);
  font-style: italic;
}

/* Images */
.article-body img {
  max-width: 100%;
  height: auto;
  border-radius: 10px;
  margin: 28px 0;
  border: 1px solid var(--border);
}

/* Horizontal rule */
.article-body hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 56px 0;
}

/* IJPB callout */
.ijpb-callout {
  background: var(--sky-tint);
  border: 1px solid rgba(124, 188, 238, 0.25);
  border-left: 3px solid var(--sky);
  border-radius: 10px;
  padding: 22px 26px;
  margin: 36px 0;
  font-size: 1rem;
}

.ijpb-callout strong {
  display: block;
  margin-bottom: 6px;
  color: var(--sky-deep);
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.ijpb-callout p:last-child { margin-bottom: 0; }

/* ═══════════════════════════════════
   ARTICLE FOOTER
   ═══════════════════════════════════ */
.article-footer {
  border-top: 1px solid var(--border);
  padding: 28px clamp(20px, 4vw, 48px);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8125rem;
  color: var(--text-subtle);
  font-family: 'DM Sans', sans-serif;
  flex-wrap: wrap;
  gap: 12px;
}

.article-footer a {
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.article-footer a:hover {
  color: var(--sky-deep);
}

/* ═══════════════════════════════════
   ARTICLES INDEX
   ═══════════════════════════════════ */
.articles-index {
  max-width: 720px;
  margin: 0 auto;
  padding: 80px clamp(20px, 4vw, 32px) 120px;
  font-family: 'DM Sans', -apple-system, sans-serif;
  color: var(--text);
}

.articles-index h1 {
  font-family: "Bagel Fat One", system-ui, sans-serif;
  font-weight: 400;
  font-size: clamp(2.25rem, 5vw, 3.25rem);
  line-height: 1.1;
  letter-spacing: -0.01em;
  margin: 0 0 12px;
  color: var(--dark);
}

.articles-index .subtitle {
  color: var(--text-muted);
  font-size: 1.125rem;
  margin: 0 0 56px;
  line-height: 1.6;
  max-width: 560px;
}

.article-card {
  border-bottom: 1px solid var(--border);
  padding: 28px 0;
  transition: padding 0.2s ease;
}

.article-card:last-child { border-bottom: none; }

.article-card a {
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--dark);
  text-decoration: none;
  transition: color 0.15s;
  display: inline-block;
  margin-bottom: 6px;
}

.article-card a:hover { color: var(--sky-deep); }

.article-card .card-desc {
  color: var(--text-muted);
  margin: 0 0 10px;
  font-size: 1rem;
  line-height: 1.55;
}

.article-card .card-date {
  font-size: 0.8125rem;
  color: var(--text-subtle);
  margin: 0;
  letter-spacing: 0.02em;
}

/* ═══════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════ */
@media (max-width: 640px) {
  .article-body {
    font-size: 1.0625rem;
    padding: 56px 20px 80px;
  }
  .articles-index {
    padding: 56px 20px 80px;
  }
}