/* ═══════════════════════════════════════════════════════════
   Droplet Labs — v4 design system
   Dark-first product polish (kaedim-inspired), droplet-blue brand.
   Display: Space Grotesk · Body/UI: Inter · Logo: Urbanist · ZH: Noto Sans SC
   Structure and content unchanged from v3 (brief remains copy source).
   ═══════════════════════════════════════════════════════════ */

:root, html[data-theme="dark"] {
  --bg: #0A0D12;
  --bg-2: #0D1117;
  --surface: rgba(255, 255, 255, .035);
  --surface-2: rgba(255, 255, 255, .06);
  --surface-solid: #12161D;
  --text: #EEF1F4;
  --text-muted: #98A2AE;
  --rule: rgba(255, 255, 255, .09);
  --accent: #4FC3F7;
  --accent-2: #7FD8E8;
  --accent-deep: #2E9FD6;
  --accent-ink: #06222F;
  --grad: linear-gradient(115deg, #2E9FD6, #5BC8F5 55%, #7FD8E8);
  --glow: rgba(79, 195, 247, .22);
  --card-shadow: 0 14px 40px rgba(3, 10, 16, .5);
  --wm-ghost: #1D242C;
  --refr-cool: #7FD8E8;
  --refr-warm: #E8B57F;
  --logo-blue: #2E9FD6;
  --ink: #111418; /* logo cross — constant across themes */
}
html[data-theme="light"] {
  --bg: #FAFBFC;
  --bg-2: #F3F5F7;
  --surface: #FFFFFF;
  --surface-2: #F0F3F5;
  --surface-solid: #FFFFFF;
  --text: #12161C;
  --text-muted: #5B6672;
  --rule: #E3E7EB;
  --accent: #0F7DBE;
  --accent-2: #2E9FD6;
  --accent-deep: #0E6DA6;
  --accent-ink: #06222F;
  --grad: linear-gradient(115deg, #1583C7, #2E9FD6 55%, #56B8DF);
  --glow: rgba(46, 159, 214, .18);
  --card-shadow: 0 10px 30px rgba(18, 34, 48, .08);
  --wm-ghost: #E8EAE9;
}

:root {
  --display: 'Space Grotesk', 'Inter', system-ui, sans-serif;
  --body-font: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --logo-font: 'Urbanist', var(--body-font);
  --ease: cubic-bezier(.22, .6, .2, 1);
  --fast: .22s;
  --measure: 64ch;
}
html.zh {
  --display: 'Noto Sans SC', 'Space Grotesk', 'Microsoft YaHei', sans-serif;
  --body-font: 'Noto Sans SC', 'Inter', 'Microsoft YaHei', 'PingFang SC', sans-serif;
  --measure: 40em;
}

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

html { scroll-behavior: smooth; overflow-x: clip; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--body-font);
  font-size: 16.5px;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  transition: background var(--fast), color var(--fast);
  overflow-x: hidden;
}
html.zh body { line-height: 1.78; }

/* language switching */
.t-zh { display: none; }
html.zh .t-zh { display: inline; }
html.zh .t-en { display: none; }

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--accent-2); }
html[data-theme="light"] a:hover { color: var(--accent-deep); }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }
::selection { background: var(--accent-deep); color: #fff; }
img { max-width: 100%; }

.visually-hidden {
  position: absolute; width: 1px; height: 1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap;
}

/* ── compact type scale ──────────────────────────── */
h1, .h1 {
  font-family: var(--display);
  font-size: clamp(34px, 4.8vw, 58px);
  font-weight: 700; line-height: 1.06;
  letter-spacing: -.032em; text-wrap: balance;
}
h2, .h2 {
  font-family: var(--display);
  font-size: clamp(24px, 2.8vw, 35px);
  font-weight: 600; line-height: 1.12;
  letter-spacing: -.022em; text-wrap: balance;
}
h3, .h3 {
  font-family: var(--display);
  font-size: clamp(18px, 1.7vw, 21px);
  font-weight: 600; line-height: 1.25;
  letter-spacing: -.012em;
}
html.zh h1, html.zh .h1 { letter-spacing: 0; line-height: 1.18; }
html.zh h2, html.zh .h2 { letter-spacing: 0; line-height: 1.3; }
html.zh h3, html.zh .h3 { letter-spacing: 0; line-height: 1.4; }
p { max-width: var(--measure); }
.muted { color: var(--text-muted); }

.eyebrow {
  font-family: var(--body-font);
  font-size: 13px; font-weight: 600; line-height: 1.5;
  letter-spacing: .18em; text-transform: uppercase;
  color: var(--accent);
}
html.zh .eyebrow { letter-spacing: .32em; }
.smallnote { font-size: 14.5px; line-height: 1.55; color: var(--text-muted); }

/* ── logo mark — exact v4 SVG (blue drop, black X, ringed nodes) ── */
.mark {
  display: inline-block;
  width: .56em; height: .67em;
  position: relative; top: .045em;
  margin: 0 .02em; flex-shrink: 0;
  overflow: visible;
}
.mark .mk-drop { fill: var(--logo-blue); }
.mark .mk-x { stroke: var(--ink); stroke-width: 16; stroke-linecap: round; fill: none; }
.mark .mk-nodes circle { fill: var(--logo-blue); stroke: var(--ink); stroke-width: 8; }

.nav-logo:hover .mark,
.nav-logo:focus-visible .mark { animation: markPulse .28s var(--ease); }
@keyframes markPulse {
  0% { transform: scale(1); }
  45% { transform: scale(1.12); }
  100% { transform: scale(1); }
}
.refract, .nav-logo:hover .mark {
  filter: drop-shadow(1px 0 0 var(--refr-cool)) drop-shadow(-1px 0 0 var(--refr-warm));
}

/* ── wordmark lockups ────────────────────────────── */
.wordmark {
  display: inline-flex; align-items: center; gap: .045em;
  font-family: var(--logo-font);
  font-weight: 500; letter-spacing: .03em; line-height: 1;
  white-space: nowrap; color: var(--text);
}
.wordmark .wm-gap { width: .32em; }
.wordmark .wm-labs { font-weight: 400; color: var(--text-muted); }
.wm-nav { font-size: 25px; }

.wm-stack {
  display: inline-flex; flex-direction: column; gap: .1em;
  font-family: var(--logo-font);
  font-weight: 500; letter-spacing: .03em; line-height: 1;
  font-size: clamp(44px, 6vw, 72px);
  color: var(--wm-ghost);
}
.wm-stack .wm-row { display: flex; align-items: center; gap: .045em; }
.wm-stack .wm-labs-stack {
  font-weight: 400; color: var(--text-muted);
  font-size: .40em; letter-spacing: .52em;
  padding-left: .06em;
}

/* ── header / nav ────────────────────────────────── */
.nav {
  position: sticky; top: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  gap: 18px; padding: 13px clamp(20px, 4vw, 44px);
  background: color-mix(in srgb, var(--bg) 72%, transparent);
  -webkit-backdrop-filter: blur(18px) saturate(1.4);
  backdrop-filter: blur(18px) saturate(1.4);
  border-bottom: 1px solid transparent;
  transition: border-color var(--fast);
}
.nav.scrolled { border-bottom-color: var(--rule); }
.nav-logo { text-decoration: none; }

.nav-links { display: flex; align-items: center; gap: 6px; }
.nav-links > a, .dd-btn {
  font-family: var(--body-font); font-size: 15px; font-weight: 500; line-height: 1.2;
  color: var(--text-muted); text-decoration: none;
  background: none; border: none; cursor: pointer;
  padding: 8px 14px; border-radius: 999px;
  transition: color var(--fast), background var(--fast);
}
.nav-links > a:hover, .dd-btn:hover { color: var(--text); background: var(--surface-2); }
.nav-links > a[aria-current="page"] { color: var(--accent); background: color-mix(in srgb, var(--accent) 12%, transparent); }

/* Solutions dropdown — hover-safe (bridge + delay), click, focus, Escape */
.dd { position: relative; }
.dd-btn .caret { font-size: 11px; color: var(--text-muted); margin-left: 5px; display: inline-block; transition: transform var(--fast); }
.dd.open .dd-btn .caret { transform: rotate(180deg); }
.dd-menu {
  position: absolute; top: calc(100% + 10px); left: 0;
  min-width: 230px;
  background: color-mix(in srgb, var(--surface-solid) 92%, transparent);
  -webkit-backdrop-filter: blur(18px);
  backdrop-filter: blur(18px);
  border: 1px solid var(--rule);
  border-radius: 14px; padding: 8px;
  box-shadow: var(--card-shadow);
  display: none; flex-direction: column;
}
/* invisible bridge covering the 10px gap so hover never drops */
.dd-menu::before {
  content: ''; position: absolute;
  top: -12px; left: 0; right: 0; height: 12px;
}
.dd.open .dd-menu { display: flex; animation: ddIn .18s var(--ease); }
@keyframes ddIn { from { opacity: 0; transform: translateY(-4px); } to { opacity: 1; transform: none; } }
.dd-menu a {
  font-family: var(--body-font); font-size: 15px; font-weight: 500;
  color: var(--text); text-decoration: none;
  padding: 10px 12px; border-radius: 9px;
  transition: background var(--fast), color var(--fast);
}
.dd-menu a:hover, .dd-menu a:focus-visible { background: var(--surface-2); color: var(--accent); }
.dd-menu a[aria-current="page"] { color: var(--accent); }

.nav-right { display: flex; align-items: center; gap: 10px; }

/* theme toggle — droplet fills (dark) / drains (light) */
.theme-toggle {
  background: none; border: 1px solid var(--rule); border-radius: 999px;
  width: 40px; height: 34px; cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center;
  color: var(--text); transition: border-color var(--fast), background var(--fast);
}
.theme-toggle:hover { border-color: var(--accent); background: var(--surface-2); }
.theme-toggle svg { display: block; }
.theme-toggle .tt-outline { stroke: currentColor; fill: none; stroke-width: 1.6; }
.theme-toggle .tt-fill { fill: currentColor; transform: translateY(19px); transition: transform .26s var(--ease); }
html[data-theme="dark"] .theme-toggle .tt-fill { transform: translateY(0); }

.lang-toggle {
  background: none; border: 1px solid var(--rule); border-radius: 999px;
  font-family: var(--body-font); font-size: 13.5px; font-weight: 500; letter-spacing: .03em;
  color: var(--text-muted); padding: 7px 13px; cursor: pointer;
  display: inline-flex; gap: 6px;
  transition: border-color var(--fast), background var(--fast);
}
.lang-toggle:hover { border-color: var(--accent); background: var(--surface-2); }
.lang-toggle .lt-en { color: var(--text); }
html.zh .lang-toggle .lt-en { color: var(--text-muted); }
html.zh .lang-toggle .lt-zh { color: var(--text); }
.lang-toggle .lt-sep { color: var(--rule); }

/* burger + mobile menu */
.burger {
  display: none; background: none; border: none; cursor: pointer;
  width: 40px; height: 36px; position: relative; z-index: 201;
}
.burger span {
  position: absolute; left: 9px; right: 9px; height: 2px; border-radius: 2px;
  background: var(--text); transition: transform .25s var(--ease), top .25s var(--ease);
}
.burger span:nth-child(1) { top: 13px; }
.burger span:nth-child(2) { top: 21px; }
body.menu-open .burger span:nth-child(1) { top: 17px; transform: rotate(45deg); }
body.menu-open .burger span:nth-child(2) { top: 17px; transform: rotate(-45deg); }

.mobile-menu {
  position: fixed; inset: 0; z-index: 200;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  -webkit-backdrop-filter: blur(22px);
  backdrop-filter: blur(22px);
  display: none; flex-direction: column; justify-content: center;
  padding: 60px clamp(24px, 8vw, 60px);
}
body.menu-open .mobile-menu { display: flex; }
.mobile-menu nav { display: flex; flex-direction: column; }
.mobile-menu a {
  font-family: var(--display); font-size: 27px; font-weight: 600; letter-spacing: -.02em;
  color: var(--text); text-decoration: none;
  padding: 13px 0; border-bottom: 1px solid var(--rule);
  transition: color var(--fast);
}
.mobile-menu a:hover { color: var(--accent); }
.mobile-menu .mm-sub { font-size: 19px; padding-left: 22px; color: var(--text-muted); }
.mm-foot { margin-top: 40px; }

/* ── layout: editorial grid, tightened ───────────── */
.page { max-width: 1150px; margin: 0 auto; padding: 0 clamp(20px, 4vw, 44px); }

.sec {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 256px;
  gap: 52px;
  padding: clamp(44px, 6vw, 76px) 0;
  position: relative;
}
.sec-main { min-width: 0; position: relative; z-index: 1; }
.sec-main > * + * { margin-top: 18px; }
.sec-main h2 + p, .sec-main h1 + p { margin-top: 22px; }
.sec-margin {
  position: relative; z-index: 1;
  border-left: 1px solid var(--rule);
  padding-left: 22px;
}
.sec-margin .eyebrow { display: block; padding-top: 6px; }
.margin-note { font-size: 14.5px; line-height: 1.55; color: var(--text-muted); margin-top: 16px; max-width: 32ch; }

/* meniscus divider */
.divider { display: block; width: 100%; height: 9px; color: var(--rule); }

/* ── margin glossary ─────────────────────────────── */
.g {
  font: inherit; color: inherit;
  background: none; border: none; padding: 0; cursor: help;
  border-bottom: 1px dotted var(--accent);
  transition: color var(--fast);
}
.g:hover, .g[aria-expanded="true"] {
  color: var(--accent);
  box-shadow: 0 1px 0 var(--refr-cool), 0 2px 0 color-mix(in srgb, var(--refr-warm) 65%, transparent);
}
.gloss-card {
  position: absolute; left: 22px; right: 0;
  font-size: 14.5px; line-height: 1.55;
  color: var(--text);
  background: var(--surface-solid);
  border: 1px solid var(--rule);
  border-left: 2px solid var(--accent);
  border-radius: 12px; padding: 14px 15px;
  box-shadow: var(--card-shadow);
  opacity: 0; visibility: hidden;
  transition: opacity .18s var(--ease);
}
.gloss-card.show { opacity: 1; visibility: visible; }
.gloss-card .gc-term { display: block; font-weight: 600; margin-bottom: 6px; color: var(--accent); }
.gloss-inline {
  display: block;
  font-size: 14.5px; line-height: 1.55;
  background: var(--surface); border: 1px solid var(--rule);
  border-left: 2px solid var(--accent);
  border-radius: 0 12px 12px 0;
  padding: 12px 14px; margin: 12px 0;
  max-width: var(--measure);
}
.gloss-inline .gc-term { display: block; font-weight: 600; color: var(--accent); margin-bottom: 4px; }

/* ── buttons (pill, gradient primary) ────────────── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-family: var(--body-font); font-size: 15px; font-weight: 600; line-height: 1.2;
  letter-spacing: .01em;
  text-decoration: none; cursor: pointer;
  padding: 13px 26px; border-radius: 999px;
  border: 1px solid transparent;
  transition: transform var(--fast), box-shadow var(--fast), border-color var(--fast), background var(--fast), color var(--fast);
}
.btn-primary {
  background: var(--grad); color: var(--accent-ink);
  box-shadow: 0 4px 18px var(--glow);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 10px 30px var(--glow); color: var(--accent-ink); }
.btn-ghost { border-color: var(--rule); color: var(--text); background: var(--surface); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-2px); }
.btn-row { display: flex; gap: 14px; flex-wrap: wrap; margin-top: 30px; }
.btn-nav { padding: 9px 18px; font-size: 14px; }

/* ── hero ────────────────────────────────────────── */
.hero { overflow: visible; }
.hero::before, .hero::after {
  content: ''; position: absolute; border-radius: 50%;
  filter: blur(90px); pointer-events: none; z-index: 0;
}
.hero::before {
  width: 480px; height: 480px; top: -160px; left: -180px;
  background: radial-gradient(circle, var(--glow), transparent 65%);
  animation: orbA 16s ease-in-out infinite alternate;
}
.hero::after {
  width: 420px; height: 420px; top: 40px; right: -160px;
  background: radial-gradient(circle, color-mix(in srgb, var(--accent-2) 20%, transparent), transparent 65%);
  animation: orbB 20s ease-in-out infinite alternate;
}
@keyframes orbA { to { transform: translate(60px, 40px) scale(1.12); } }
@keyframes orbB { to { transform: translate(-50px, 60px) scale(.92); } }

#ripples { position: absolute; inset: 0; width: 100%; height: 100%; z-index: 0; pointer-events: none; }

.hero .sec-main { padding: clamp(16px, 3.5vw, 36px) 0; }
.hero-drop {
  font-size: 96px; line-height: 0; display: block; margin-bottom: 36px;
  animation: bob 6s ease-in-out infinite;
}
@keyframes bob { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-9px); } }
.hero-drop .mark {
  top: 0; margin: 0; width: .9em; height: 1.08em;
  filter: drop-shadow(1px 0 0 var(--refr-cool)) drop-shadow(-1px 0 0 var(--refr-warm)) drop-shadow(0 10px 30px var(--glow));
}

.hero h1 {
  background: linear-gradient(180deg, var(--text) 55%, color-mix(in srgb, var(--text) 55%, var(--accent-2)));
  -webkit-background-clip: text; background-clip: text;
  color: transparent;
}
.hero p.lede {
  font-size: clamp(17px, 1.9vw, 19.5px); line-height: 1.55;
  color: var(--text-muted); margin-top: 24px;
}
html.zh .hero p.lede { line-height: 1.75; }

/* ── marquee ─────────────────────────────────────── */
.marquee {
  overflow: hidden; padding: 16px 0;
  border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule);
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
  mask-image: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
}
.marquee-track {
  display: flex; gap: 34px; width: max-content;
  font-family: var(--body-font); font-size: 13px; font-weight: 600;
  letter-spacing: .2em; text-transform: uppercase; color: var(--text-muted);
  animation: marquee 30s linear infinite;
}
.marquee-track i { font-style: normal; color: var(--accent); }
.marquee:hover .marquee-track { animation-play-state: paused; }
@keyframes marquee { to { transform: translateX(-50%); } }

/* ── cards ───────────────────────────────────────── */
.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 34px; }
.card {
  display: flex; flex-direction: column; gap: 11px;
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 16px;
  padding: 24px 22px;
  text-decoration: none; color: var(--text);
  transition: transform .25s var(--ease), border-color var(--fast), box-shadow .25s var(--ease), background var(--fast);
}
.card:hover {
  transform: translateY(-5px);
  border-color: color-mix(in srgb, var(--accent) 45%, var(--rule));
  box-shadow: 0 16px 40px var(--glow);
  background: var(--surface-2);
}
.card .eyebrow { font-size: 12px; }
.card h3 { font-size: 18.5px; line-height: 1.28; }
.card:hover h3 { color: var(--accent); }
.card p { font-size: 14.5px; line-height: 1.55; color: var(--text-muted); flex: 1; }
.card .card-date { font-size: 13.5px; color: var(--text-muted); }

/* ── how we work (only numbered sequence) ────────── */
.steps { display: flex; flex-direction: column; margin-top: 10px; }
.step {
  display: grid; grid-template-columns: 64px minmax(0, 1fr);
  gap: 18px; padding: 22px 0;
  border-bottom: 1px solid var(--rule);
}
.step:last-child { border-bottom: none; }
.step-num {
  font-family: var(--display); font-size: 26px; font-weight: 700; line-height: 1.15;
  background: var(--grad);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.step h3 { margin-bottom: 6px; }
.step p { color: var(--text-muted); font-size: 15.5px; }

/* ── believe list ────────────────────────────────── */
.believe { list-style: none; margin-top: 8px; }
.believe li {
  padding: 14px 0 14px 32px; position: relative;
  border-bottom: 1px solid var(--rule);
  max-width: var(--measure);
  font-size: 16px;
}
.believe li:last-child { border-bottom: none; }
.believe li::before {
  content: ''; position: absolute; left: 6px; top: 24px;
  width: 9px; height: 9px;
  background: var(--grad);
  border-radius: 50% 50% 50% 0;
  transform: rotate(135deg);
}

/* ── services (Partner) ──────────────────────────── */
.service {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 16px;
  padding: 26px 26px 24px;
  margin-top: 16px;
  transition: border-color var(--fast), box-shadow .25s var(--ease);
}
.service:hover { border-color: color-mix(in srgb, var(--accent) 40%, var(--rule)); box-shadow: 0 12px 34px var(--glow); }
.service:first-of-type { margin-top: 26px; }
.service .promise {
  font-family: var(--display);
  color: var(--accent); font-size: 16.5px; font-weight: 500; margin-top: 6px;
}
.service p { margin-top: 14px; font-size: 15.5px; }
.service .typical {
  display: inline-block; margin-top: 14px;
  font-size: 13px; font-weight: 600; letter-spacing: .04em;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
  border-radius: 999px; padding: 5px 12px;
}

/* ── FAQ accordion ───────────────────────────────── */
.faq {
  border: 1px solid var(--rule); border-radius: 14px;
  background: var(--surface);
  max-width: var(--measure);
  padding: 0 20px; margin-top: 10px;
  transition: border-color var(--fast);
}
.faq:hover, .faq[open] { border-color: color-mix(in srgb, var(--accent) 35%, var(--rule)); }
.faq summary {
  font-size: 15.5px; font-weight: 600;
  padding: 16px 32px 16px 0; cursor: pointer;
  list-style: none; position: relative;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: '+'; position: absolute; right: 2px; top: 50%;
  transform: translateY(-50%);
  font-size: 20px; font-weight: 400; color: var(--accent);
  transition: transform var(--fast);
}
.faq[open] summary::after { content: '–'; }
.faq p { padding: 0 0 18px; color: var(--text-muted); font-size: 15px; }

/* ── team ────────────────────────────────────────── */
.team-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-top: 30px; }
.person {
  background: var(--surface); border: 1px solid var(--rule);
  border-radius: 16px; padding: 28px 26px;
  transition: transform .25s var(--ease), border-color var(--fast), box-shadow .25s var(--ease);
}
.person:hover { transform: translateY(-4px); border-color: color-mix(in srgb, var(--accent) 40%, var(--rule)); box-shadow: 0 14px 36px var(--glow); }
.person .avatar { font-size: 58px; line-height: 0; display: block; margin-bottom: 22px; }
.person .avatar .mark { top: 0; margin: 0; }
.person h3 { font-size: 20px; }
.person .role { font-size: 13px; font-weight: 600; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); margin: 6px 0 12px; }
.person p { font-size: 14.5px; line-height: 1.6; color: var(--text-muted); }

/* ── article pages ───────────────────────────────── */
.art-meta {
  display: flex; flex-wrap: wrap; gap: 8px 16px; align-items: baseline;
  font-size: 14px; color: var(--text-muted);
  margin-top: 18px;
}
.art-body > * + * { margin-top: 20px; }
.art-body h2 { margin-top: 40px; }
.art-body ul, .art-body ol { padding-left: 24px; max-width: var(--measure); }
.art-body li + li { margin-top: 9px; }
.related { margin-top: 22px; display: flex; flex-direction: column; gap: 9px; }
.related a { font-size: 15.5px; font-weight: 500; text-decoration: none; }
.related a:hover { text-decoration: underline; }

/* research index list */
.res-list { display: flex; flex-direction: column; gap: 14px; margin-top: 28px; }
.res-item {
  display: block; text-decoration: none; color: var(--text);
  background: var(--surface); border: 1px solid var(--rule);
  border-radius: 16px; padding: 24px 26px;
  transition: transform .25s var(--ease), border-color var(--fast), box-shadow .25s var(--ease);
}
.res-item:hover {
  transform: translateY(-4px);
  border-color: color-mix(in srgb, var(--accent) 45%, var(--rule));
  box-shadow: 0 14px 36px var(--glow);
}
.res-item:hover h3 { color: var(--accent); }
.res-item .eyebrow { margin-bottom: 8px; display: block; font-size: 12px; }
.res-item p { font-size: 15px; color: var(--text-muted); margin-top: 8px; }
.res-item .card-date { font-size: 13.5px; color: var(--text-muted); margin-top: 10px; display: block; }
.filters { display: flex; flex-direction: column; gap: 8px; margin-top: 18px; align-items: flex-start; }
.filters button {
  font-family: var(--body-font); font-size: 13.5px; font-weight: 500; text-align: left;
  background: none; border: 1px solid transparent; border-radius: 999px;
  cursor: pointer; color: var(--text-muted); padding: 5px 12px;
  transition: color var(--fast), border-color var(--fast), background var(--fast);
}
.filters button:hover { color: var(--accent); }
.filters button.active {
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  border-color: color-mix(in srgb, var(--accent) 35%, transparent);
}

/* ── subscribe / notify ──────────────────────────── */
.mini-form { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 22px; max-width: 480px; }
.mini-form input {
  flex: 1; min-width: 220px;
  font-family: var(--body-font); font-size: 15px;
  color: var(--text); background: var(--surface);
  border: 1px solid var(--rule); border-radius: 999px;
  padding: 12px 18px;
  transition: border-color var(--fast);
}
.mini-form input:focus { outline: 2px solid var(--accent); outline-offset: 1px; border-color: transparent; }
.mini-form input::placeholder { color: var(--text-muted); }

/* ── closing CTA band ────────────────────────────── */
.cta-band {
  position: relative; overflow: hidden;
  background:
    radial-gradient(ellipse 60% 90% at 50% 120%, var(--glow), transparent 70%),
    var(--surface);
  border: 1px solid var(--rule);
  border-radius: 22px;
  padding: clamp(34px, 5vw, 56px);
  margin: 16px 0 56px;
  text-align: center;
}
.cta-band p { color: var(--text-muted); margin: 12px auto 0; }
.cta-band .btn-row, .cta-band .mini-form { justify-content: center; margin-left: auto; margin-right: auto; }

/* ── footer ──────────────────────────────────────── */
.footer { border-top: 1px solid var(--rule); padding: 60px 0 36px; margin-top: 30px; background: var(--bg-2); }
.footer-grid {
  display: grid; grid-template-columns: minmax(0, 1.2fr) repeat(2, minmax(140px, .6fr));
  gap: 44px;
}
.fcol-h { font-size: 12px; font-weight: 600; letter-spacing: .16em; text-transform: uppercase; color: var(--text-muted); margin-bottom: 13px; }
.fcol { display: flex; flex-direction: column; gap: 9px; }
.fcol a { font-size: 14.5px; color: var(--text-muted); text-decoration: none; transition: color var(--fast); }
.fcol a:hover { color: var(--accent); }
.footer-tag { font-size: 14.5px; color: var(--text-muted); margin-top: 20px; max-width: 34ch; }
.footer-bar {
  display: flex; justify-content: space-between; gap: 14px; flex-wrap: wrap;
  border-top: 1px solid var(--rule);
  margin-top: 48px; padding-top: 22px;
  font-size: 13px; color: var(--text-muted);
}

/* ── waterline scroll progress ───────────────────── */
.waterline {
  position: fixed; left: 12px; top: 0; bottom: 0; width: 1px;
  background: var(--rule); z-index: 50;
}
.waterline i {
  position: absolute; bottom: 0; left: 0; width: 1px;
  height: var(--wl, 0%);
  background: linear-gradient(0deg, var(--accent-deep), var(--accent-2));
  box-shadow: 0 0 8px var(--glow);
}
@media (max-width: 1260px) { .waterline { display: none; } }

/* ── 404 ─────────────────────────────────────────── */
.err { min-height: 60vh; display: flex; flex-direction: column; justify-content: center; }

/* ── scroll reveals (enabled by JS via html.anim) ── */
html.anim .rv {
  opacity: 0; transform: translateY(22px);
  transition: opacity .65s var(--ease), transform .65s var(--ease);
  transition-delay: var(--rvd, 0s);
}
html.anim .rv.in { opacity: 1; transform: none; }

/* ── reduced motion ──────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
  html.anim .rv { opacity: 1; transform: none; }
}

/* ── responsive ──────────────────────────────────── */
@media (max-width: 1100px) { .btn-nav { display: none; } }
@media (max-width: 1024px) {
  .nav-links { display: none; }
  .burger { display: block; }
}
@media (max-width: 900px) {
  .sec { grid-template-columns: 1fr; gap: 0; }
  .sec-margin { order: -1; border-left: none; padding-left: 0; margin-bottom: 16px; }
  .margin-note { max-width: var(--measure); }
  .gloss-card { display: none; }
  .card-grid { grid-template-columns: 1fr; }
  .team-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .hero::before { left: -240px; }
  .hero::after { right: -240px; }
}
@media (max-width: 640px) {
  body { font-size: 16px; }
  .step { grid-template-columns: 48px 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .btn-row .btn { width: 100%; }
  .nav { padding: 11px 18px; }
  .hero-drop { font-size: 76px; }
}