/* Open Brief - Knowledge & Science Explainer Magazine */

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

:root {
  --bsn-paper:  #f7f4ed;
  --bsn-card:   #ffffff;
  --bsn-ink:    #1c1c1c;
  --bsn-ink2:   #2e2e2e;
  --bsn-rule:   #e0dbd0;
  --bsn-rule2:  #c8c0b0;
  --bsn-red:    #c0392b;
  --bsn-red2:   #96281b;
  --bsn-muted:  #5a5550;
  --bsn-pale:   #8c857c;
  --bsn-hilite: #fff8f6;
  --bsn-wrap:   1100px;
  --bsn-read:   740px;
  --bsn-r:      4px;
}

html { font-size: 16px; scroll-behavior: smooth; }
body {
  background: var(--bsn-paper);
  color: var(--bsn-ink);
  font-family: Georgia, 'Iowan Old Style', 'Times New Roman', serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--bsn-red); text-decoration: none; }
a:hover { color: var(--bsn-red2); text-decoration: underline; }
img { max-width: 100%; display: block; }

/* ===== Masthead: centered print-magazine style ===== */
.bsn-masthead {
  background: var(--bsn-paper);
  border-bottom: 1px solid var(--bsn-rule);
  text-align: center;
}
.bsn-mast-top {
  border-top: 4px solid var(--bsn-ink);
  border-bottom: 1px solid var(--bsn-ink);
  margin: 0 auto;
  max-width: var(--bsn-wrap);
  padding: 0 24px;
}
.bsn-mast-inner {
  padding: 18px 24px 16px;
  max-width: var(--bsn-wrap);
  margin: 0 auto;
}
.bsn-mast-name {
  font-family: Georgia, 'Times New Roman', serif;
  display: block;
  font-size: clamp(2.2rem, 5vw, 3.6rem);
  font-weight: bold;
  color: var(--bsn-ink);
  letter-spacing: -0.03em;
  text-decoration: none;
  line-height: 1;
  margin-bottom: 6px;
}
.bsn-mast-name:hover { color: var(--bsn-ink); text-decoration: none; }
.bsn-mast-sub {
  font-family: Georgia, serif;
  font-size: 0.78rem;
  font-style: italic;
  color: var(--bsn-muted);
  letter-spacing: 0.06em;
}
.bsn-mast-bot {
  border-top: 1px solid var(--bsn-ink);
}

/* Navigation row below masthead */
.bsn-nav {
  background: var(--bsn-paper);
  border-bottom: 1px solid var(--bsn-rule2);
}
.bsn-nav-row {
  max-width: var(--bsn-wrap);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: center;
  gap: 0;
  flex-wrap: wrap;
}
.bsn-nav-row a {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--bsn-ink2);
  padding: 10px 20px;
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: border-color 0.15s, color 0.15s;
}
.bsn-nav-row a:hover,
.bsn-nav-row a[aria-current="page"] {
  color: var(--bsn-red);
  border-bottom-color: var(--bsn-red);
  text-decoration: none;
}

/* ===== Category strip (section pills) ===== */
.bsn-catstrip {
  background: var(--bsn-card);
  border-bottom: 1px solid var(--bsn-rule);
  overflow-x: auto;
}
.bsn-catstrip-row {
  max-width: var(--bsn-wrap);
  margin: 0 auto;
  padding: 10px 24px;
  display: flex;
  gap: 8px;
  flex-wrap: nowrap;
  white-space: nowrap;
}
.bsn-catstrip-row a {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--bsn-muted);
  background: var(--bsn-paper);
  border: 1px solid var(--bsn-rule2);
  border-radius: 20px;
  padding: 5px 14px;
  text-decoration: none;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.bsn-catstrip-row a:hover {
  background: var(--bsn-red);
  color: #fff;
  border-color: var(--bsn-red);
  text-decoration: none;
}

/* ===== Layout shell ===== */
.bsn-wrap { max-width: var(--bsn-wrap); margin: 0 auto; padding: 0 24px; }

/* ===== Hero intro band ===== */
.bsn-hero {
  background: var(--bsn-ink);
  color: #e8e4dd;
  padding: 40px 24px 38px;
  text-align: center;
}
.bsn-hero-inner {
  max-width: 720px;
  margin: 0 auto;
}
.bsn-hero-eyebrow {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--bsn-red);
  margin-bottom: 14px;
  display: block;
}
.bsn-hero h1 {
  font-family: Georgia, serif;
  font-size: clamp(1.7rem, 3.6vw, 2.6rem);
  font-weight: bold;
  color: #fff;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}
.bsn-hero p {
  font-size: 1rem;
  color: #b8b0a6;
  line-height: 1.75;
  max-width: 600px;
  margin: 0 auto;
}

/* ===== Section headers ===== */
.bsn-sechead {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 40px 0 22px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--bsn-ink);
  flex-wrap: wrap;
}
.bsn-sechead h2 {
  font-family: Georgia, serif;
  font-size: 1.05rem;
  font-weight: bold;
  color: var(--bsn-ink);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.bsn-sechead-link {
  margin-left: auto;
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--bsn-red);
}

/* ===== Card grid (3-column magazine layout) ===== */
.bsn-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
  margin-bottom: 44px;
}
@media (max-width: 860px) { .bsn-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .bsn-grid { grid-template-columns: 1fr; } }

.bsn-card {
  background: var(--bsn-card);
  border: 1px solid var(--bsn-rule);
  border-radius: var(--bsn-r);
  padding: 22px 20px 20px;
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.18s;
}
.bsn-card:hover { box-shadow: 0 2px 12px rgba(0,0,0,0.08); }

.bsn-card-tag {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  display: inline-block;
  font-size: 0.64rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--bsn-red);
  border-top: 2px solid var(--bsn-red);
  padding-top: 6px;
  margin-bottom: 12px;
}
.bsn-card h3 {
  font-family: Georgia, serif;
  font-size: 1.08rem;
  font-weight: bold;
  color: var(--bsn-ink);
  line-height: 1.35;
  margin-bottom: 10px;
}
.bsn-card h3 a { color: var(--bsn-ink); text-decoration: none; }
.bsn-card h3 a:hover { color: var(--bsn-red); text-decoration: none; }
.bsn-card p {
  font-size: 0.9rem;
  color: var(--bsn-muted);
  line-height: 1.62;
  flex-grow: 1;
  margin-bottom: 16px;
}
.bsn-card-more {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--bsn-red);
  align-self: flex-start;
}
.bsn-card-more:hover { color: var(--bsn-red2); text-decoration: none; }

/* ===== Stream list (used in inc/latest.php) ===== */
.bsn-stream {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
@media (max-width: 860px) { .bsn-stream { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .bsn-stream { grid-template-columns: 1fr; } }

.bsn-stream li {
  background: var(--bsn-card);
  border: 1px solid var(--bsn-rule);
  border-radius: var(--bsn-r);
  padding: 20px;
}
.bsn-label {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  display: inline-block;
  font-size: 0.62rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--bsn-red);
  border-top: 2px solid var(--bsn-red);
  padding-top: 5px;
  margin-bottom: 10px;
}
.bsn-stream li h3 {
  font-family: Georgia, serif;
  font-size: 1.04rem;
  font-weight: bold;
  color: var(--bsn-ink);
  line-height: 1.34;
  margin-bottom: 8px;
}
.bsn-stream li h3 a { color: var(--bsn-ink); text-decoration: none; }
.bsn-stream li h3 a:hover { color: var(--bsn-red); }
.bsn-stream li p { font-size: 0.88rem; color: var(--bsn-muted); line-height: 1.6; }

/* ===== Info band at bottom of homepage ===== */
.bsn-band {
  background: var(--bsn-card);
  border: 1px solid var(--bsn-rule);
  border-radius: var(--bsn-r);
  padding: 36px 40px;
  margin: 44px 0;
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr 1fr;
  gap: 30px;
}
@media (max-width: 860px) { .bsn-band { grid-template-columns: 1fr 1fr; } }
@media (max-width: 560px) { .bsn-band { grid-template-columns: 1fr; gap: 22px; } }
.bsn-band-intro h2 {
  font-family: Georgia, serif;
  font-size: 1.26rem;
  font-weight: bold;
  color: var(--bsn-ink);
  line-height: 1.3;
  margin-bottom: 10px;
}
.bsn-band-intro p { font-size: 0.88rem; color: var(--bsn-muted); line-height: 1.65; }
.bsn-band-col h4 {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  font-size: 0.66rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--bsn-pale);
  border-top: 2px solid var(--bsn-rule2);
  padding-top: 10px;
  margin-bottom: 12px;
}
.bsn-band-col a {
  display: block;
  font-size: 0.86rem;
  color: var(--bsn-ink2);
  margin-bottom: 7px;
  text-decoration: none;
}
.bsn-band-col a:hover { color: var(--bsn-red); text-decoration: none; }

/* ===== Footer ===== */
.bsn-foot {
  background: var(--bsn-ink);
  color: #9e9790;
  margin-top: 0;
  border-top: 3px solid var(--bsn-red);
}
.bsn-foot-main {
  max-width: var(--bsn-wrap);
  margin: 0 auto;
  padding: 36px 24px 24px;
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr;
  gap: 32px;
  border-bottom: 1px solid rgba(255,255,255,0.07);
}
@media (max-width: 720px) { .bsn-foot-main { grid-template-columns: 1fr; gap: 22px; } }
.bsn-foot-brand {
  font-family: Georgia, serif;
}
.bsn-foot-brand b {
  display: block;
  font-size: 1.3rem;
  color: #fff;
  margin-bottom: 10px;
}
.bsn-foot-brand p { font-size: 0.84rem; color: #7a736c; line-height: 1.65; max-width: 340px; }
.bsn-foot-col h4 {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  font-size: 0.64rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #5e5850;
  margin-bottom: 12px;
}
.bsn-foot-col a {
  display: block;
  color: #8a827a;
  font-size: 0.86rem;
  margin-bottom: 7px;
  text-decoration: none;
}
.bsn-foot-col a:hover { color: #e8e4dd; text-decoration: none; }
.bsn-foot-fine {
  max-width: var(--bsn-wrap);
  margin: 0 auto;
  padding: 16px 24px 28px;
  font-size: 0.74rem;
  color: #4e4840;
  line-height: 1.6;
}

/* ===== Article page ===== */
.bsn-article {
  max-width: var(--bsn-read);
  margin: 0 auto;
  padding: 42px 24px 80px;
}
.bsn-crumbs {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  font-size: 0.76rem;
  color: var(--bsn-pale);
  margin-bottom: 20px;
}
.bsn-crumbs a { color: var(--bsn-red); text-decoration: none; }
.bsn-crumbs a:hover { text-decoration: underline; }
.bsn-art-tag {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  display: inline-block;
  font-size: 0.66rem;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--bsn-red);
  border-top: 2px solid var(--bsn-red);
  padding-top: 5px;
  margin-bottom: 14px;
}
.bsn-article h1 {
  font-family: Georgia, serif;
  font-size: clamp(1.7rem, 4vw, 2.55rem);
  font-weight: bold;
  color: var(--bsn-ink);
  line-height: 1.2;
  letter-spacing: -0.025em;
  margin-bottom: 18px;
}
.bsn-byline {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  font-size: 0.8rem;
  color: var(--bsn-pale);
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
  padding-bottom: 22px;
  margin-bottom: 28px;
  border-bottom: 1px solid var(--bsn-rule2);
}
.bsn-dot { color: var(--bsn-rule2); }

/* Key points box */
.bsn-keybox {
  background: var(--bsn-hilite);
  border: 1px solid #e8d8d4;
  border-left: 4px solid var(--bsn-red);
  border-radius: var(--bsn-r);
  padding: 20px 24px;
  margin-bottom: 30px;
}
.bsn-keybox b {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  display: block;
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--bsn-red2);
  margin-bottom: 10px;
}
.bsn-keybox ul { margin: 0 0 0 18px; }
.bsn-keybox li { font-size: 0.94rem; color: var(--bsn-ink2); margin-bottom: 6px; line-height: 1.6; }

/* Prose content */
.bsn-prose p { margin-bottom: 20px; font-size: 1.04rem; line-height: 1.82; }
.bsn-prose h2 {
  font-family: Georgia, serif;
  font-size: 1.32rem;
  font-weight: bold;
  color: var(--bsn-ink);
  margin: 36px 0 12px;
  line-height: 1.3;
  border-top: 1px solid var(--bsn-rule);
  padding-top: 28px;
}
.bsn-prose h3 {
  font-family: Georgia, serif;
  font-size: 1.08rem;
  font-weight: bold;
  color: var(--bsn-ink2);
  margin: 24px 0 8px;
}
.bsn-prose ul, .bsn-prose ol { margin: 0 0 20px 26px; font-size: 1.01rem; line-height: 1.76; }
.bsn-prose li { margin-bottom: 8px; }
.bsn-prose strong { color: var(--bsn-ink); }
.bsn-prose em { font-style: italic; color: var(--bsn-ink2); }
.bsn-prose blockquote {
  border-left: 3px solid var(--bsn-rule2);
  background: var(--bsn-card);
  padding: 14px 20px;
  margin: 0 0 22px;
  color: var(--bsn-muted);
  font-style: italic;
}

/* Summary/takeaway box */
.bsn-summary {
  background: var(--bsn-ink);
  border-radius: var(--bsn-r);
  padding: 24px 28px;
  margin: 34px 0 0;
}
.bsn-summary b {
  font-family: 'Helvetica Neue', Arial, system-ui, sans-serif;
  display: block;
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--bsn-red);
  margin-bottom: 8px;
}
.bsn-summary p { font-size: 0.97rem; color: #c8c0b8; margin-bottom: 0; line-height: 1.68; }

/* ===== Responsive ===== */
@media (max-width: 640px) {
  .bsn-mast-inner { padding: 14px 18px 12px; }
  .bsn-nav-row { gap: 0; }
  .bsn-nav-row a { padding: 10px 12px; font-size: 0.7rem; }
  .bsn-hero { padding: 28px 18px; }
  .bsn-article { padding: 28px 18px 60px; }
  .bsn-band { padding: 24px 20px; }
}