/* Research section, on top of styles.css (nav, footer, newsletter).
   Technique borrowed from research-lab article pages: topic tags over a serif title, a quiet
   date and author line, outlined resource buttons, a rule, then serif section heads over a
   sans reading column. Colours stay the site's light navy identity. */

.rs-page { background: #fff; }
.rs-col { max-width: 700px; margin: 0 auto; padding: 0 24px; }
.rs-serif { font-family: 'Source Serif 4', Georgia, 'Times New Roman', serif; }

/* ---------- article header ---------- */
.rs-article { padding: 124px 0 24px; }
.rs-head { border-bottom: 1px solid var(--gray-200); padding-bottom: 30px; margin-bottom: 36px; }
.rs-tags { display: flex; flex-wrap: wrap; gap: 6px 18px; margin: 0 0 16px; padding: 0; list-style: none; }
.rs-tags li { font: 600 12.5px/1.2 var(--font-sans); letter-spacing: 0.085em; text-transform: uppercase; color: var(--accent); }
.rs-title {
  font-family: 'Source Serif 4', Georgia, serif; font-weight: 700;
  font-size: 46px; line-height: 1.12; letter-spacing: -0.012em;
  color: var(--navy); margin: 0 0 16px;
}
.rs-sub { font: 400 20px/1.5 var(--font-sans); color: var(--text-muted); margin: 0 0 22px; }
.rs-metaline {
  display: flex; flex-wrap: wrap; align-items: center; gap: 6px 12px; margin: 0 0 22px;
  font: 500 13px/1.3 var(--font-sans); color: var(--gray-400);
}
.rs-metaline time { text-transform: uppercase; letter-spacing: 0.06em; }
.rs-metaline a { color: var(--text-muted); text-decoration: none; }
.rs-metaline a:hover { color: var(--accent); }
.rs-sep { width: 1px; height: 13px; background: var(--gray-200); }
.rs-links { display: flex; flex-wrap: wrap; gap: 10px; margin: 0; }
.rs-links a {
  display: inline-flex; align-items: center; gap: 7px;
  padding: 7px 13px; border: 1px solid var(--gray-200); border-radius: 6px; background: #fff;
  font: 500 14px/1 var(--font-sans); color: var(--text); text-decoration: none;
  transition: border-color var(--transition), color var(--transition);
}
.rs-links a:hover { border-color: var(--accent); color: var(--accent); }
.rs-links svg { width: 12px; height: 12px; flex: none; opacity: 0.7; }
.rs-cover { margin: 0 0 38px; }
.rs-cover img { width: 100%; height: auto; display: block; border-radius: 6px; }

/* ---------- article body: sans reading text, serif section heads ---------- */
.rs-body { font: 400 18.5px/1.78 var(--font-sans); color: #33405a; }
.rs-body p { margin: 0 0 1.35em; }
.rs-body h2 {
  font-family: 'Source Serif 4', Georgia, serif; font-weight: 700;
  font-size: 30px; line-height: 1.25; letter-spacing: -0.005em;
  color: var(--navy); margin: 2em 0 0.55em;
}
.rs-body h3 { font: 700 20px/1.35 var(--font-sans); color: var(--navy); margin: 1.8em 0 0.5em; }
.rs-body a { color: var(--accent); text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 3px; }
.rs-body a:hover { color: var(--navy); }
.rs-body strong { font-weight: 700; color: var(--text); }
.rs-body ul, .rs-body ol { margin: 0 0 1.35em; padding-left: 1.4em; }
.rs-body li { margin: 0.45em 0; padding-left: 0.25em; }
.rs-body li::marker { color: var(--gray-400); }
.rs-body code {
  font: 0.84em/1 'JetBrains Mono', Consolas, monospace;
  background: var(--gray-100); color: var(--text); padding: 0.14em 0.38em; border-radius: 4px;
}
.rs-body pre { background: #1e1e2e; color: #e6e6f0; padding: 18px 20px; border-radius: 6px; overflow-x: auto; margin: 0 0 1.6em; font-size: 13.5px; line-height: 1.6; }
.rs-body pre code { display: block; background: none; padding: 0; font-size: 13.5px; line-height: 1.6; color: inherit; white-space: pre; }
.rs-body figure { margin: 2.3em 0; }
.rs-body figure img, .rs-body figure video { width: 100%; height: auto; display: block; border-radius: 6px; }
.rs-body figcaption { font: 400 14px/1.5 var(--font-sans); color: var(--gray-400); text-align: center; margin-top: 10px; }
.rs-body > p:last-child em { display: block; font-size: 15px; line-height: 1.65; color: var(--gray-400); border-top: 1px solid var(--gray-200); padding-top: 18px; margin-top: 8px; }

/* video link: thumbnail that opens YouTube (same redirect pattern as the rest of the site) */
.rs-video { position: relative; display: block; }
.rs-video::after {
  content: ''; position: absolute; left: 50%; top: 50%; width: 68px; height: 48px;
  transform: translate(-50%, -50%); border-radius: 12px; background: rgba(27,42,74,.88);
}
.rs-video::before {
  content: ''; position: absolute; left: 50%; top: 50%; z-index: 1; transform: translate(-35%, -50%);
  border-style: solid; border-width: 11px 0 11px 18px; border-color: transparent transparent transparent #fff;
}

/* tables: header underline and thin row rules, nothing else */
.rs-table-wrap { overflow-x: auto; margin: 2em 0 2.2em; }
.rs-body table { border-collapse: collapse; width: 100%; font: 400 15px/1.45 var(--font-sans); color: var(--text); }
.rs-body th { text-align: left; font-weight: 600; color: var(--navy); border-bottom: 1.5px solid var(--navy); padding: 8px 10px; vertical-align: bottom; }
.rs-body td { border-bottom: 1px solid var(--gray-200); padding: 9px 10px; vertical-align: top; }
.rs-body .num { text-align: right; font-variant-numeric: tabular-nums; }
.rs-body td.num { white-space: nowrap; }
.rs-body td.best { font-weight: 700; color: var(--accent); }

/* bar chart built in HTML so the text stays legible at phone width */
.rs-chart { margin: 2.2em 0 2.4em; font-family: var(--font-sans); }
.rs-body .rs-chart-title { font: 600 15px/1.4 var(--font-sans); color: var(--navy); margin: 0 0 4px; }
.rs-body .rs-chart-group { font: 600 11.5px/1 var(--font-sans); letter-spacing: 0.07em; text-transform: uppercase; color: var(--gray-400); margin: 22px 0 6px; }
.rs-bar-row { display: grid; grid-template-columns: 230px 1fr 46px; align-items: center; gap: 12px; padding: 4px 0; border-radius: 4px; }
.rs-bar-row:hover { background: var(--off-white); }
.rs-bar-label { font-size: 14.5px; color: var(--text); line-height: 1.3; }
.rs-bar-track {
  position: relative; height: 20px;
  background-image: linear-gradient(to right, var(--gray-200) 1px, transparent 1px);
  background-size: 25% 100%;
  box-shadow: inset -1px 0 0 var(--gray-200);
}
.rs-bar { display: block; height: 100%; background: #1E56B8; border-radius: 0 4px 4px 0; }
.rs-bar-val { font-size: 14px; font-weight: 600; color: var(--text); text-align: right; font-variant-numeric: tabular-nums; }
.rs-chart figcaption { text-align: left; }

/* ---------- subscribe block, placed right after the introduction ---------- */
.rs-cta { margin: 2.2em 0 2.4em; }
.rs-body .rs-cta .nb-newsletter-title { font: 700 20px/1.3 var(--font-sans); color: var(--navy); margin: 0 0 6px; }
.rs-body .rs-cta p { font-size: 15.5px; line-height: 1.55; margin: 0 0 14px; }
.rs-body .rs-cta .nb-newsletter-status { margin: 8px 0 0; }
.rs-cta-x {
  display: flex; flex-wrap: wrap; align-items: center; gap: 10px 12px;
  margin: 16px 0 0 !important; padding-top: 16px; border-top: 1px solid #d8dff0;
  font: 500 14.5px/1.3 var(--font-sans); color: var(--text-muted);
}
.rs-btn { display: inline-flex; align-items: center; gap: 8px; padding: 9px 16px; border-radius: 999px; font: 600 14px/1 var(--font-sans); text-decoration: none !important; }
.rs-btn svg { width: 15px; height: 15px; }
.rs-btn-x { background: #0f1419; color: #fff !important; }
.rs-btn-x:hover { background: #2f3336; }

/* ---------- latest video card ---------- */
.rs-watch {
  display: grid; grid-template-columns: 196px 1fr; gap: 18px; align-items: center;
  margin: 52px 0 0; padding: 22px 0 0; border-top: 1px solid var(--gray-200);
  text-decoration: none; color: inherit; font-family: var(--font-sans);
}
.rs-watch > span { display: block; }
.rs-watch-thumb { position: relative; }
.rs-watch-thumb img { width: 196px; aspect-ratio: 16 / 9; object-fit: cover; border-radius: 6px; display: block; }
.rs-watch-kicker { display: flex; align-items: center; gap: 7px; font: 600 12px/1 var(--font-sans); letter-spacing: 0.07em; text-transform: uppercase; color: var(--gray-400); margin-bottom: 8px; }
.rs-watch-kicker svg { width: 16px; height: 16px; color: #e5231b; }
.rs-watch-kicker svg .rs-knock { fill: #fff; }
.rs-watch-title { display: block; font: 700 17px/1.35 var(--font-sans); color: var(--navy); margin-bottom: 4px; }
.rs-watch:hover .rs-watch-title { text-decoration: underline; text-underline-offset: 3px; }
.rs-watch-line { display: block; font: 400 14.5px/1.5 var(--font-sans); color: var(--text-muted); }

/* ---------- written by: author card ---------- */
.rs-author-card {
  margin: 36px 0 0; padding: 44px 32px 38px; border-radius: 20px;
  background: var(--navy); color: #fff; text-align: center; font-family: var(--font-sans);
}
.rs-ac-photo { width: 92px; height: 92px; border-radius: 50%; object-fit: cover; border: 3px solid rgba(255,255,255,.92); display: block; margin: 0 auto; }
.rs-ac-name { font: 700 26px/1.25 var(--font-sans); color: #fff; margin: 18px 0 12px; }
.rs-ac-bio { font: 400 16px/1.62 var(--font-sans); color: rgba(255,255,255,.86); max-width: 520px; margin: 0 auto 26px; }
.rs-ac-bio a { color: #fff; text-decoration: underline; text-underline-offset: 3px; }
.rs-ac-buttons { display: flex; flex-direction: column; gap: 12px; max-width: 420px; margin: 0 auto 28px; }
.rs-ac-btn {
  display: flex; align-items: center; justify-content: center; gap: 10px;
  padding: 14px 20px; border-radius: 999px; font: 600 16px/1 var(--font-sans); text-decoration: none;
  transition: background var(--transition), color var(--transition);
}
.rs-ac-btn svg { width: 18px; height: 18px; }
.rs-ac-primary { background: #fff; color: var(--navy); }
.rs-ac-primary:hover { background: #e7ecf7; }
.rs-ac-ghost { border: 1.5px solid rgba(255,255,255,.7); color: #fff; }
.rs-ac-ghost:hover { background: rgba(255,255,255,.08); }
.rs-ac-ghost svg .rs-knock { fill: var(--navy); }
.rs-ac-more { font: 500 15px/1.3 var(--font-sans); color: rgba(255,255,255,.8); margin: 0 0 14px; }
.rs-ac-social { display: flex; justify-content: center; flex-wrap: wrap; gap: 22px; }
.rs-ac-social a { color: #fff; opacity: .9; transition: opacity var(--transition); }
.rs-ac-social a:hover { opacity: 1; }
.rs-ac-social svg { width: 26px; height: 26px; display: block; }
.rs-ac-social svg .rs-knock { fill: var(--navy); }

.rs-more { background: var(--off-white); padding: 48px 0 56px; margin-top: 56px; }
.rs-more-title { font-family: 'Source Serif 4', Georgia, serif; font-weight: 700; font-size: 24px; color: var(--navy); margin: 0 0 4px; }

/* ---------- article list (index page and "more research") ---------- */
.rs-index-head { padding: 124px 0 30px; border-bottom: 1px solid var(--gray-200); }
.rs-index-head .rs-tags { margin-bottom: 12px; }
.rs-index-head h1 { font-family: 'Source Serif 4', Georgia, serif; font-weight: 700; font-size: 46px; line-height: 1.1; color: var(--navy); margin: 0 0 12px; }
.rs-index-head p { font: 400 19px/1.55 var(--font-sans); color: var(--text-muted); margin: 0; }
.rs-list { margin: 0 0 24px; }
.rs-item {
  display: grid; grid-template-columns: 1fr 176px; gap: 28px; align-items: center;
  padding: 28px 0; border-bottom: 1px solid var(--gray-200);
  text-decoration: none; color: inherit;
}
.rs-item:last-child { border-bottom: 0; }
.rs-item .rs-tags { margin: 0 0 8px; gap: 4px 14px; }
.rs-item .rs-tags li { font-size: 11.5px; }
.rs-item-title {
  font-family: 'Source Serif 4', Georgia, serif; font-weight: 700;
  font-size: 23px; line-height: 1.25; color: var(--navy); margin: 0 0 8px;
}
.rs-item:hover .rs-item-title { text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1.5px; }
.rs-item-sub {
  font: 400 15.5px/1.55 var(--font-sans); color: var(--text-muted); margin: 0 0 10px;
  display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden;
}
.rs-item-foot { font: 500 12.5px/1.3 var(--font-sans); color: var(--gray-400); margin: 0; letter-spacing: 0.04em; text-transform: uppercase; }
.rs-item-thumb img { width: 176px; height: 118px; object-fit: cover; border-radius: 6px; display: block; }

@media (max-width: 680px) {
  .rs-article, .rs-index-head { padding-top: 100px; }
  .rs-title, .rs-index-head h1 { font-size: 33px; }
  .rs-sub { font-size: 18px; }
  .rs-body { font-size: 17px; line-height: 1.72; }
  .rs-body h2 { font-size: 25px; }
  .rs-bar-row { grid-template-columns: 1fr 44px; gap: 4px 10px; }
  .rs-bar-label { grid-column: 1 / -1; }
  .rs-item { grid-template-columns: 1fr 96px; gap: 16px; padding: 22px 0; }
  .rs-item-title { font-size: 19px; }
  .rs-item-sub { font-size: 14.5px; -webkit-line-clamp: 2; }
  .rs-item-thumb img { width: 96px; height: 64px; }
  .rs-watch { grid-template-columns: 120px 1fr; gap: 14px; }
  .rs-watch-thumb img { width: 120px; }
  .rs-author-card { padding: 36px 20px 30px; }
  .rs-ac-name { font-size: 22px; }
}