/* ==========================================================================
   ai-4-science.com — shared design system
   A quiet, academic editorial language: warm paper, ink, hairline rules,
   one serif family, generous whitespace. Light + dark. EN / 中文.

   Sections
   01 Tokens        02 Reset          03 Base          04 Typography
   05 Layout        06 Links          07 Buttons       08 Header
   09 Mobile nav    10 Hero           11 Section head  12 Meta strip
   13 Feature       14 News           15 Research index 16 People
   17 Publications  18 Patents        19 Service       20 Figures
   21 Tables        22 Prose          23 Page head     24 Footer
   25 Utilities     26 Motion         27 Print
   ========================================================================== */

/* 01 — Tokens -------------------------------------------------------------- */

:root {
  --font-serif: "Source Serif 4", "Songti SC", "STSong", "Source Han Serif SC",
    "Noto Serif CJK SC", "SimSun", Georgia, "Times New Roman", serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue",
    Arial, sans-serif;
  --font-mono: "SFMono-Regular", "JetBrains Mono", Menlo, Consolas,
    "Liberation Mono", monospace;

  --maxw: 1160px;
  --maxw-text: 760px;
  --gutter: clamp(20px, 4.2vw, 44px);
  --header-h: 76px;

  --bg: #faf8f3;
  --bg-alt: #f3efe6;
  --surface: #ffffff;
  --ink: #1a1917;
  --ink-2: #454138;
  --ink-3: #6f6a5e;
  --rule: #e3ddd0;
  --rule-strong: #cec5b2;
  --accent: #1c3f66;
  --accent-hover: #122c49;
  --accent-soft: #e9eef4;
  --warm: #9a4a2f;
  --tag-ink: #5b5445;
  --selection: #e8dfca;
  --shadow: 0 1px 2px rgba(26, 25, 23, 0.04), 0 8px 28px rgba(26, 25, 23, 0.05);

  --ease: cubic-bezier(0.22, 0.61, 0.24, 1);
  --radius: 3px;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --bg: #14130f;
  --bg-alt: #1b1a15;
  --surface: #1e1d17;
  --ink: #ece6d9;
  --ink-2: #c0b9aa;
  --ink-3: #928b7c;
  --rule: #2d2b24;
  --rule-strong: #413e32;
  --accent: #9dbdde;
  --accent-hover: #bcd2ea;
  --accent-soft: #22303f;
  --warm: #d38f6e;
  --tag-ink: #c4bca8;
  --selection: #3a3527;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.35), 0 10px 30px rgba(0, 0, 0, 0.35);
}

/* 02 — Reset --------------------------------------------------------------- */

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body,
h1,
h2,
h3,
h4,
h5,
h6,
p,
figure,
blockquote,
dl,
dd,
ul,
ol {
  margin: 0;
  padding: 0;
}

ul[role="list"],
ol[role="list"] {
  list-style: none;
}

img,
picture,
svg,
video {
  display: block;
  max-width: 100%;
}

img {
  height: auto;
}

input,
button,
textarea,
select {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  background: none;
  border: 0;
}

hr {
  border: 0;
  border-top: 1px solid var(--rule);
  margin: 0;
}

::selection {
  background: var(--selection);
  color: var(--ink);
}

/* Bilingual visibility: the <html lang> attribute is the single switch. */

html[lang="en"] .lang-zh {
  display: none !important;
}

html[lang="zh-CN"] .lang-en {
  display: none !important;
}

/* 03 — Base ---------------------------------------------------------------- */

html {
  background: var(--bg);
}

body {
  min-height: 100vh;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.72;
  font-kerning: normal;
  font-variant-ligatures: common-ligatures;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color 0.35s var(--ease), color 0.35s var(--ease);
}

html[lang="zh-CN"] body {
  line-height: 1.85;
  letter-spacing: 0.01em;
  text-wrap: pretty;
}

main {
  display: block;
}

[id] {
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.skip-link {
  position: fixed;
  top: -100px;
  left: 16px;
  z-index: 300;
  padding: 10px 16px;
  background: var(--ink);
  color: var(--bg);
  font: 500 13px/1 var(--font-sans);
  border-radius: var(--radius);
  transition: top 0.2s var(--ease);
}

.skip-link:focus-visible {
  top: 12px;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 1px;
}

/* 04 — Typography ---------------------------------------------------------- */

.display,
h1,
h2,
h3 {
  font-family: var(--font-serif);
  font-weight: 500;
  color: var(--ink);
  text-wrap: balance;
}

.display {
  font-size: clamp(2.45rem, 6.4vw, 4.65rem);
  line-height: 1.03;
  letter-spacing: -0.028em;
}

h1 {
  font-size: clamp(2.15rem, 4.6vw, 3.35rem);
  line-height: 1.08;
  letter-spacing: -0.022em;
}

h2 {
  font-size: clamp(1.65rem, 3vw, 2.35rem);
  line-height: 1.14;
  letter-spacing: -0.016em;
}

h3 {
  font-size: clamp(1.1rem, 1.7vw, 1.3rem);
  line-height: 1.32;
  letter-spacing: -0.008em;
  font-weight: 600;
}

.display em,
h1 em,
h2 em,
.serif-italic {
  font-style: italic;
  font-weight: 400;
  color: var(--accent);
}

html[lang="zh-CN"] .display,
html[lang="zh-CN"] h1,
html[lang="zh-CN"] h2 {
  letter-spacing: 0;
  line-height: 1.22;
}

html[lang="zh-CN"] .display em,
html[lang="zh-CN"] h1 em,
html[lang="zh-CN"] h2 em {
  font-style: normal;
  color: inherit;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.17em;
  line-height: 1.5;
  text-transform: uppercase;
  color: var(--ink-3);
}

.eyebrow::before {
  content: "";
  width: 6px;
  height: 6px;
  background: var(--warm);
  flex: none;
}

html[lang="zh-CN"] .eyebrow {
  letter-spacing: 0.14em;
}

.lede {
  font-size: clamp(1.08rem, 1.55vw, 1.24rem);
  line-height: 1.68;
  color: var(--ink-2);
  max-width: 62ch;
}

.lede--wide {
  max-width: 72ch;
}

.body-text {
  color: var(--ink-2);
  max-width: 68ch;
}

.body-text + .body-text {
  margin-top: 1.1em;
}

.small {
  font-size: 0.88rem;
}

.micro {
  font-family: var(--font-sans);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--ink-3);
}

.caption {
  font-family: var(--font-sans);
  font-size: 12.5px;
  line-height: 1.65;
  letter-spacing: 0.01em;
  color: var(--ink-3);
  max-width: 82ch;
}

.muted {
  color: var(--ink-3);
}

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

.warm {
  color: var(--warm);
}

.nowrap {
  white-space: nowrap;
}

.center {
  text-align: center;
}

.center .eyebrow {
  justify-content: center;
}

.center .lede {
  margin-inline: auto;
}

.center .btn-row {
  justify-content: center;
}

.numeric {
  font-variant-numeric: tabular-nums lining-nums;
}

/* 05 — Layout -------------------------------------------------------------- */

.container {
  width: min(100% - 2 * var(--gutter), var(--maxw));
  margin-inline: auto;
}

.container--text {
  width: min(100% - 2 * var(--gutter), var(--maxw-text));
  margin-inline: auto;
}

.container--wide {
  width: min(100% - 2 * var(--gutter), 1280px);
  margin-inline: auto;
}

.section {
  padding-block: clamp(38px, 5.2vw, 70px);
}

.section--tight {
  padding-block: clamp(26px, 3.3vw, 42px);
}

.section--flush-top {
  padding-top: 0;
}

.grid {
  display: grid;
  gap: clamp(24px, 3.4vw, 44px);
}

.grid--2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid--3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid--feature {
  grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
  align-items: center;
}

.rule {
  border-top: 1px solid var(--rule);
}

.stack-sm > * + * {
  margin-top: 12px;
}

.stack > * + * {
  margin-top: 24px;
}

.stack-lg > * + * {
  margin-top: 28px;
}

/* 06 — Links --------------------------------------------------------------- */

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
  text-decoration-color: color-mix(in srgb, var(--accent) 40%, transparent);
  transition: color 0.2s var(--ease), text-decoration-color 0.2s var(--ease);
}

a:hover {
  color: var(--accent-hover);
  text-decoration-color: currentColor;
}

.link-plain {
  color: inherit;
  text-decoration: none;
}

.link-plain:hover {
  color: inherit;
  text-decoration: none;
}

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--accent);
  text-decoration: none;
}

.link-arrow::after {
  content: "→";
  font-size: 15px;
  line-height: 1;
  transition: transform 0.25s var(--ease);
}

.link-arrow:hover::after {
  transform: translateX(4px);
}

.link-arrow--back::after {
  content: none;
}

.link-arrow--back::before {
  content: "←";
  font-size: 15px;
  line-height: 1;
}

.text-link {
  font-family: var(--font-sans);
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--accent);
  text-decoration: underline;
  text-decoration-color: color-mix(in srgb, var(--accent) 45%, transparent);
  text-underline-offset: 0.18em;
}

.text-link:hover {
  text-decoration-color: currentColor;
}

/* 07 — Buttons ------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 13px 22px;
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius);
  background: transparent;
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: 0.05em;
  line-height: 1;
  text-decoration: none;
  text-transform: uppercase;
  white-space: nowrap;
  transition: background-color 0.22s var(--ease), border-color 0.22s var(--ease),
    color 0.22s var(--ease), transform 0.22s var(--ease);
}

.btn:hover {
  border-color: var(--ink);
  color: var(--ink);
  text-decoration: none;
  transform: translateY(-1px);
}

.btn--primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fbfaf6;
}

.btn--primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  color: #ffffff;
}

html[data-theme="dark"] .btn--primary {
  color: #10151c;
}

html[data-theme="dark"] .btn--primary:hover {
  color: #0b0f14;
}

.btn--ghost {
  background: transparent;
}

.btn--small {
  padding: 9px 14px;
  font-size: 11px;
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 11px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--ink-3);
  background: transparent;
}

.pill--accent {
  color: var(--accent);
  border-color: color-mix(in srgb, var(--accent) 35%, transparent);
}

.dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--warm);
  flex: none;
}

/* 08 — Header -------------------------------------------------------------- */

#site-header {
  min-height: var(--header-h);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 120;
  background: transparent;
  border-bottom: 1px solid var(--rule);
}

/* The blur lives on a pseudo-element: `backdrop-filter` on the header itself would
   become the containing block of the position:fixed mobile menu (clipping it). */
.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  -webkit-backdrop-filter: saturate(140%) blur(14px);
  backdrop-filter: saturate(140%) blur(14px);
  pointer-events: none;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(20px, 3vw, 48px);
  height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 13px;
  color: var(--ink);
  text-decoration: none;
  flex: none;
}

.brand:hover {
  color: var(--ink);
  text-decoration: none;
}

.brand-mark {
  width: 30px;
  height: 30px;
  flex: none;
  color: var(--accent);
}

.brand-monogram {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  flex: none;
  border: 1px solid var(--rule-strong);
  border-radius: 50%;
  font-family: var(--font-serif);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--ink-2);
}

.brand-copy {
  display: flex;
  flex-direction: column;
  gap: 2px;
  line-height: 1.1;
}

.brand-name {
  font-family: var(--font-serif);
  font-size: 1.06rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.brand-sub {
  font-family: var(--font-sans);
  font-size: 9.5px;
  font-weight: 500;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--ink-3);
  white-space: nowrap;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(18px, 2.4vw, 34px);
  margin-left: auto;
}

.nav-link {
  position: relative;
  font-family: var(--font-sans);
  font-size: 12.5px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--ink-2);
  text-decoration: none;
  padding: 6px 0;
  white-space: nowrap;
  transition: color 0.2s var(--ease);
}

.nav-link:hover {
  color: var(--ink);
  text-decoration: none;
}

.nav-link[aria-current="page"] {
  color: var(--ink);
}

.nav-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 1px;
  background: var(--accent);
}

.nav-link .ext {
  font-size: 10px;
  vertical-align: 1px;
  color: var(--ink-3);
}

.header-tools {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: none;
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-family: var(--font-sans);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.04em;
}

.lang-btn {
  padding: 3px 2px;
  color: var(--ink-3);
  line-height: 1;
  border-radius: 1px;
  transition: color 0.2s var(--ease);
}

.lang-btn:hover {
  color: var(--ink);
}

.lang-btn[aria-pressed="true"] {
  color: var(--ink);
  font-weight: 600;
}

.lang-sep {
  color: var(--rule-strong);
  font-size: 10px;
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border: 1px solid var(--rule);
  border-radius: 50%;
  color: var(--ink-2);
  background: transparent;
  transition: border-color 0.2s var(--ease), color 0.2s var(--ease),
    background-color 0.2s var(--ease);
}

.icon-btn:hover {
  border-color: var(--rule-strong);
  color: var(--ink);
  background: var(--bg-alt);
}

.icon-btn svg {
  width: 16px;
  height: 16px;
}

.theme-icon-sun {
  display: none;
}

html[data-theme="dark"] .theme-icon-sun {
  display: block;
}

html[data-theme="dark"] .theme-icon-moon {
  display: none;
}

.menu-btn {
  display: none;
}

.menu-btn svg + svg {
  display: none;
}

.nav-open .menu-btn svg:first-child {
  display: none;
}

.nav-open .menu-btn svg:last-child {
  display: block;
}

@media (max-width: 1080px) {
  .brand-sub {
    display: none;
  }
}

/* 09 — Mobile nav ---------------------------------------------------------- */

@media (max-width: 920px) {
  :root {
    --header-h: 64px;
  }

  .brand-sub {
    display: none;
  }
  .menu-btn {
    display: inline-flex;
  }

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 110;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    margin: 0;
    padding: 12px var(--gutter) 40px;
    background: var(--bg);
    border-bottom: 1px solid var(--rule);
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.22s var(--ease), transform 0.22s var(--ease),
      visibility 0.22s;
  }

  .nav-open .site-nav {
    opacity: 1;
    visibility: visible;
    transform: none;
  }

  .nav-link {
    width: 100%;
    padding: 17px 0;
    border-bottom: 1px solid var(--rule);
    font-size: 15px;
  }

  .nav-link[aria-current="page"]::after {
    display: none;
  }

  .nav-link[aria-current="page"] {
    color: var(--accent);
  }

  .nav-open body {
    overflow: hidden;
  }
}

/* 10 — Hero ---------------------------------------------------------------- */

.hero {
  padding-block: clamp(42px, 5.6vw, 76px) clamp(28px, 3.8vw, 50px);
}

.hero .eyebrow {
  margin-bottom: clamp(15px, 2.2vw, 24px);
}

.hero .display {
  max-width: 17ch;
}

html[lang="zh-CN"] .hero .display {
  max-width: 20ch;
}

.hero-lede {
  margin-top: clamp(17px, 2.3vw, 27px);
  max-width: 60ch;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px 22px;
  margin-top: clamp(19px, 2.5vw, 29px);
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 28px;
  margin-top: clamp(23px, 3.1vw, 35px);
  padding-top: 14px;
  border-top: 1px solid var(--rule);
  font-family: var(--font-sans);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--ink-3);
}

.hero-meta strong {
  color: var(--ink-2);
  font-weight: 500;
}

.page-head {
  padding-block: clamp(36px, 4.8vw, 60px) clamp(20px, 2.7vw, 32px);
  border-bottom: 1px solid var(--rule);
}

.page-head .eyebrow {
  margin-bottom: 16px;
}

.page-head h1 {
  max-width: 24ch;
}

.page-head .lede {
  margin-top: 16px;
}

.page-head--center {
  text-align: center;
}

.page-head--center h1,
.page-head--center .lede {
  margin-inline: auto;
}

/* 11 — Section head -------------------------------------------------------- */

.section-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 12px 28px;
  align-items: end;
  margin-bottom: clamp(19px, 2.4vw, 28px);
}

.section-head .eyebrow {
  grid-column: 1 / -1;
  margin-bottom: 4px;
}

.section-head h2 {
  max-width: 26ch;
}

.section-head .lede {
  margin-top: 8px;
}

.section-head > .link-arrow {
  align-self: end;
  padding-bottom: 6px;
}

.section-head--rule {
  padding-bottom: 16px;
  border-bottom: 1px solid var(--rule);
}

html[lang="zh-CN"] .section-head h2 {
  max-width: 30ch;
}

/* 12 — Meta strip / stats -------------------------------------------------- */

.stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.stat {
  padding: clamp(14px, 1.8vw, 22px) clamp(12px, 1.6vw, 22px);
  border-right: 1px solid var(--rule);
}

.stat:last-child {
  border-right: 0;
}

.stat-value {
  font-family: var(--font-serif);
  font-size: clamp(1.4rem, 2.2vw, 1.85rem);
  font-weight: 500;
  line-height: 1.15;
  letter-spacing: -0.015em;
}

.stat-label {
  margin-top: 7px;
  font-family: var(--font-sans);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-3);
  line-height: 1.5;
}

/* 13 — Feature ------------------------------------------------------------- */

.feature {
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
  gap: clamp(22px, 3vw, 46px);
  align-items: center;
}

.feature-media {
  position: relative;
  margin: 0;
}

.feature-media .figure-img {
  padding: clamp(8px, 1.4vw, 14px);
  background: #ffffff;
}

.feature-body .eyebrow {
  margin-bottom: 16px;
}

.feature-body h2,
.feature-body h3 {
  max-width: 24ch;
  font-size: clamp(1.42rem, 2.3vw, 1.82rem);
  line-height: 1.22;
  letter-spacing: -0.014em;
}

.feature-body .lede {
  margin-top: 13px;
  font-size: 1.02rem;
}

.feature-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: 19px 0 0;
  padding: 15px 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.metric-value {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: -0.01em;
}

.metric-label {
  margin-top: 5px;
  font-family: var(--font-sans);
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-3);
  line-height: 1.4;
}

.feature-body .btn-row {
  margin-top: 19px;
}

/* 14 — News ---------------------------------------------------------------- */

.news-list {
  border-top: 1px solid var(--rule);
}

.news-item {
  display: grid;
  grid-template-columns: 104px minmax(0, 1fr) auto;
  gap: 12px clamp(18px, 3vw, 40px);
  align-items: baseline;
  padding: 13px 0;
  border-bottom: 1px solid var(--rule);
}

.news-date {
  font-family: var(--font-sans);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--ink-3);
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}

.news-body {
  color: var(--ink-2);
  font-size: 0.98rem;
  line-height: 1.65;
  max-width: 74ch;
}

.news-body strong {
  color: var(--ink);
  font-weight: 600;
}

.news-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  justify-content: flex-end;
}

.news-item--plain {
  grid-template-columns: 104px minmax(0, 1fr);
}

/* 15 — Research index ------------------------------------------------------ */

.index-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 clamp(28px, 4.5vw, 64px);
}

.index-item {
  padding: clamp(15px, 2vw, 22px) 0;
  border-top: 1px solid var(--rule);
}

.index-item .index-num {
  font-family: var(--font-sans);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--warm);
}

.index-item h3 {
  margin: 7px 0 7px;
}

.index-item p {
  color: var(--ink-2);
  font-size: 0.95rem;
  line-height: 1.6;
  max-width: 52ch;
}

.index-item .link-arrow {
  margin-top: 9px;
}

.index-grid .index-item:nth-last-child(-n + 2) {
  border-bottom: 1px solid var(--rule);
}

/* 16 — People -------------------------------------------------------------- */

.people-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(28px, 4vw, 56px);
}

.person-card {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.people-grid--compact .person-card {
  display: grid;
  grid-template-columns: clamp(116px, 14vw, 164px) minmax(0, 1fr);
  gap: clamp(18px, 2.4vw, 28px);
  align-items: start;
}

.people-grid--compact .person-photo {
  aspect-ratio: 4 / 5;
}

.people-grid--compact .person-bio {
  font-size: 0.92rem;
}

.person-photo {
  width: 100%;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  object-position: 50% 22%;
  background: var(--surface);
  border: 6px solid #ffffff;
  outline: 1px solid var(--rule);
  filter: saturate(0.94);
  transition: filter 0.4s var(--ease);
}

.person-card:hover .person-photo {
  filter: saturate(1);
}

/* Compact "more selected work" strip (home page). */

.work-row {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(16px, 2.4vw, 32px);
  margin-top: clamp(20px, 2.8vw, 32px);
  padding-top: clamp(14px, 1.8vw, 20px);
  border-top: 1px solid var(--rule);
}

.work-item {
  display: block;
  text-decoration: none;
  color: inherit;
}

.work-title {
  display: block;
  font-family: var(--font-serif);
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--ink);
  line-height: 1.3;
  transition: color 0.2s var(--ease);
}

.work-meta {
  display: block;
  margin-top: 5px;
  font-family: var(--font-sans);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-3);
  line-height: 1.5;
}

.work-item:hover .work-title {
  color: var(--accent);
}

.person-name {
  font-family: var(--font-serif);
  font-size: clamp(1.25rem, 1.9vw, 1.45rem);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.person-name span:not(.lang-en):not(.lang-zh) {
  color: var(--ink-3);
  font-weight: 400;
  font-size: 0.82em;
  margin-left: 6px;
}

.person-role {
  margin-top: 5px;
  font-family: var(--font-sans);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-3);
  line-height: 1.6;
}

.person-bio {
  margin-top: 9px;
  color: var(--ink-2);
  font-size: 0.95rem;
  line-height: 1.7;
}

.person-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: 10px;
}

.profile {
  display: grid;
  grid-template-columns: minmax(200px, 300px) minmax(0, 1fr);
  gap: clamp(22px, 3.4vw, 48px);
  align-items: start;
  padding-block: clamp(26px, 3.4vw, 42px);
  border-top: 1px solid var(--rule);
}

.profile-figure {
  margin: 0;
}

.profile-photo {
  width: 100%;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  object-position: 50% 20%;
  border: 8px solid #ffffff;
  outline: 1px solid var(--rule);
  filter: saturate(0.94);
}

.profile-hero {
  display: grid;
  grid-template-columns: minmax(216px, 320px) minmax(0, 1fr);
  gap: clamp(30px, 5vw, 76px);
  align-items: center;
}

.profile-hero .profile-photo {
  border-width: 8px;
}

.profile-hero h1 {
  font-size: clamp(2.1rem, 4vw, 3.05rem);
  line-height: 1.04;
}

.profile-hero h1 .name-cn {
  display: block;
  margin-top: 6px;
  font-size: 0.52em;
  font-weight: 400;
  color: var(--ink-3);
  letter-spacing: 0.02em;
}

.profile-hero .lede {
  margin-top: 20px;
  font-size: clamp(1rem, 1.4vw, 1.1rem);
}

.profile-hero .profile-role {
  margin-top: 14px;
}

.profile-hero .keywords {
  margin-top: 22px;
}

.profile-hero .profile-links {
  margin-top: 26px;
}

.profile-caption {
  margin-top: 10px;
  font-family: var(--font-sans);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.profile-name {
  font-family: var(--font-serif);
  font-size: clamp(1.7rem, 2.8vw, 2.15rem);
  font-weight: 500;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.profile-name span:not(.lang-en):not(.lang-zh) {
  color: var(--ink-3);
  font-size: 0.7em;
  font-weight: 400;
  margin-left: 8px;
}

.profile-role {
  margin-top: 10px;
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--ink-3);
  line-height: 1.7;
}

.profile-body {
  margin-top: 16px;
}

.profile-body p {
  color: var(--ink-2);
  max-width: 66ch;
}

.profile-body p + p {
  margin-top: 1em;
}

.profile-body strong {
  color: var(--ink);
  font-weight: 600;
}

.profile-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
  margin-top: 16px;
}

.keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 13px;
}

.keyword {
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--ink-2);
  padding: 4px 10px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: transparent;
}

/* 17 — Publications -------------------------------------------------------- */

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: clamp(18px, 2.3vw, 26px);
}

.filter-label {
  margin-right: 6px;
  font-family: var(--font-sans);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.filter-btn {
  font-family: var(--font-sans);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.03em;
  color: var(--ink-2);
  padding: 7px 13px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  background: transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease),
    background-color 0.2s var(--ease);
}

.filter-btn:hover {
  border-color: var(--rule-strong);
  color: var(--ink);
}

.filter-btn[aria-pressed="true"] {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--bg);
}

.filter-count {
  margin-left: 6px;
  font-size: 10px;
  opacity: 0.62;
  font-variant-numeric: tabular-nums;
}

.pub-list {
  border-top: 1px solid var(--rule);
}

.pub-row {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: clamp(14px, 3vw, 40px);
  padding: clamp(15px, 2.1vw, 21px) 0;
  border-bottom: 1px solid var(--rule);
}

.pub-row[hidden] {
  display: none;
}

.pub-year {
  font-family: var(--font-sans);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--ink-3);
  padding-top: 5px;
  font-variant-numeric: tabular-nums;
}

.pub-main {
  min-width: 0;
}

.pub-title {
  font-family: var(--font-serif);
  font-size: clamp(1.04rem, 1.55vw, 1.18rem);
  font-weight: 600;
  line-height: 1.36;
  letter-spacing: -0.006em;
  max-width: 62ch;
}

.pub-title a {
  color: var(--ink);
  text-decoration: none;
}

.pub-title a:hover {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.16em;
}

.pub-authors {
  margin-top: 8px;
  color: var(--ink-2);
  font-size: 0.9rem;
  line-height: 1.6;
  max-width: 78ch;
}

.pub-authors strong {
  color: var(--ink);
  font-weight: 600;
}

.pub-venue {
  margin-top: 6px;
  font-size: 0.9rem;
  font-style: italic;
  color: var(--ink-2);
  max-width: 76ch;
}

.pub-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 7px;
  margin-top: 10px;
}

.pub-tldr {
  margin-top: 12px;
  font-size: 0.91rem;
  line-height: 1.65;
  color: var(--ink-2);
  max-width: 74ch;
}

.pub-tldr strong {
  color: var(--ink);
  font-weight: 600;
}

.pub-links {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 18px;
  margin-top: 14px;
}

.pub-link {
  font-family: var(--font-sans);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s var(--ease);
}

.pub-link:hover {
  border-bottom-color: currentColor;
  text-decoration: none;
}

.pub-link--primary {
  color: var(--ink);
  font-weight: 600;
}

.pub-link .ext {
  font-size: 9px;
  vertical-align: 1px;
  color: var(--ink-3);
}

.bibtex {
  position: relative;
  margin-top: 14px;
  padding: 16px 18px;
  border: 1px solid var(--rule);
  background: var(--bg-alt);
  border-radius: var(--radius);
}

.bibtex[hidden] {
  display: none;
}

.bibtex pre {
  margin: 0;
  padding-right: 78px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.6;
  color: var(--ink-2);
  overflow-x: auto;
  white-space: pre;
}

.bibtex .copy-btn {
  position: absolute;
  top: 12px;
  right: 12px;
  padding: 5px 10px;
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.05em;
  color: var(--ink-2);
  background: var(--bg);
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.bibtex .copy-btn:hover {
  color: var(--ink);
  border-color: var(--ink);
}

.tag {
  display: inline-block;
  padding: 3px 8px;
  border: 1px solid var(--rule-strong);
  border-radius: 2px;
  font-family: var(--font-sans);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  line-height: 1.5;
  color: var(--tag-ink);
  white-space: nowrap;
}

.tag--accent {
  color: var(--accent);
  border-color: color-mix(in srgb, var(--accent) 42%, transparent);
}

.tag--warm {
  color: var(--warm);
  border-color: color-mix(in srgb, var(--warm) 42%, transparent);
}

.tag--solid {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--bg);
}

/* 18 — Patents ------------------------------------------------------------- */

.patent-list {
  border-top: 1px solid var(--rule);
}

.patent-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(220px, 0.55fr);
  gap: 14px clamp(24px, 4vw, 56px);
  padding: clamp(14px, 1.9vw, 20px) 0;
  border-bottom: 1px solid var(--rule);
}

.patent-title {
  font-family: var(--font-serif);
  font-size: 1.02rem;
  font-weight: 600;
  line-height: 1.5;
}

.patent-sub {
  margin-top: 6px;
  font-family: var(--font-sans);
  font-size: 11.5px;
  color: var(--ink-3);
  letter-spacing: 0.02em;
}

.patent-meta {
  font-family: var(--font-sans);
  font-size: 11.5px;
  line-height: 1.9;
  color: var(--ink-3);
}

.patent-meta span {
  color: var(--ink-2);
}

/* 19 — Service ------------------------------------------------------------- */

.service-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(28px, 4vw, 56px);
}

.service-block {
  padding-top: 22px;
  border-top: 1px solid var(--rule);
}

.service-block h3 {
  margin-bottom: 14px;
}

.service-list {
  list-style: none;
}

.service-list li {
  display: flex;
  gap: 12px;
  padding: 7px 0;
  border-bottom: 1px solid var(--rule);
  font-size: 0.93rem;
  color: var(--ink-2);
  line-height: 1.55;
}

.service-list li:last-child {
  border-bottom: 0;
}

.service-list strong {
  color: var(--ink);
  font-weight: 600;
}

.service-list .service-year {
  flex: none;
  width: 44px;
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.05em;
  color: var(--ink-3);
  padding-top: 2px;
  font-variant-numeric: tabular-nums;
}

/* 20 — Figures ------------------------------------------------------------- */

.figure {
  margin: 0;
}

.figure-img {
  background: #ffffff;
  border: 1px solid var(--rule);
  padding: clamp(8px, 1.2vw, 14px);
}

.figure-img img {
  width: 100%;
  height: auto;
}

.figure-img--flush {
  padding: 0;
}

.figure-img--dark {
  background: #0b0b0a;
  border-color: #232219;
  padding: 0;
}

.figure figcaption {
  margin-top: 9px;
}

.fig-label {
  font-family: var(--font-sans);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--warm);
  margin-right: 8px;
}

.figure-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(18px, 2.6vw, 32px);
  align-items: start;
}

.figure-row--wide {
  grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
}

.video-plate {
  position: relative;
  border: 1px solid var(--rule);
  background: #0b0b0a;
  overflow: hidden;
}

.video-plate img {
  width: 100%;
  opacity: 0.94;
}

.video-plate .play {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(12, 11, 9, 0.18);
  color: #fff;
  text-decoration: none;
  transition: background-color 0.3s var(--ease);
}

.video-plate .play:hover {
  background: rgba(12, 11, 9, 0.05);
}

.play-badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 11px 18px;
  border: 1px solid rgba(255, 255, 255, 0.5);
  border-radius: 999px;
  background: rgba(12, 11, 9, 0.42);
  -webkit-backdrop-filter: blur(6px);
  backdrop-filter: blur(6px);
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

/* 21 — Tables -------------------------------------------------------------- */

.table-wrap {
  border: 1px solid var(--rule);
  overflow-x: auto;
  background: var(--surface);
}

html[data-theme="dark"] .table-wrap {
  background: var(--bg-alt);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-sans);
  font-size: 12.5px;
  line-height: 1.5;
}

thead th {
  padding: 11px 16px;
  text-align: left;
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-3);
  background: var(--bg-alt);
  border-bottom: 1px solid var(--rule-strong);
  white-space: nowrap;
}

tbody td {
  padding: 11px 16px;
  border-bottom: 1px solid var(--rule);
  color: var(--ink-2);
  vertical-align: top;
}

tbody tr:last-child td {
  border-bottom: 0;
}

tbody tr[data-highlight] td {
  background: var(--accent-soft);
  color: var(--ink);
}

tbody tr[data-highlight] td:first-child {
  font-weight: 600;
  color: var(--accent);
}

.table-note {
  margin-top: 10px;
}

/* 22 — Prose / callouts / lists -------------------------------------------- */

.info-list {
  list-style: none;
  border-top: 1px solid var(--rule);
}

.info-item {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr);
  gap: 10px clamp(18px, 3vw, 40px);
  padding: 11px 0;
  border-bottom: 1px solid var(--rule);
}

.info-when {
  font-family: var(--font-sans);
  font-size: 11.5px;
  letter-spacing: 0.04em;
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
  padding-top: 3px;
}

.info-body {
  font-size: 0.96rem;
  color: var(--ink-2);
  line-height: 1.6;
}

.info-body strong {
  color: var(--ink);
  font-weight: 600;
}

.paper-authors {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 28px;
  font-size: 1.02rem;
}

.paper-authors a {
  color: var(--accent);
}

.paper-affiliations {
  margin-top: 14px;
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--ink-3);
}

.paper-affiliations sup {
  font-size: 0.7em;
  margin-right: 1px;
}

.prose {
  font-size: 1.02rem;
  color: var(--ink-2);
}

.prose p {
  max-width: 70ch;
}

.prose p + p {
  margin-top: 1.05em;
}

.prose strong {
  color: var(--ink);
  font-weight: 600;
}

.prose em {
  font-style: italic;
}

.prose ul,
.prose ol {
  padding-left: 1.3em;
  max-width: 70ch;
}

.prose li + li {
  margin-top: 0.45em;
}

.callout {
  padding: 18px 0 18px 22px;
  border-left: 2px solid var(--warm);
  color: var(--ink-2);
  font-style: italic;
  max-width: 70ch;
}

.callout strong {
  color: var(--ink);
  font-style: normal;
}

.callout cite {
  display: block;
  margin-top: 8px;
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-3);
  font-style: normal;
}

.abstract-box {
  padding: clamp(22px, 3vw, 34px);
  border: 1px solid var(--rule);
  background: var(--surface);
}

html[data-theme="dark"] .abstract-box {
  background: var(--bg-alt);
}

.abstract-label {
  font-family: var(--font-sans);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--warm);
  margin-bottom: 14px;
}

.keytakeaways {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 clamp(28px, 4vw, 56px);
}

.keytakeaway {
  padding: 13px 0;
  border-top: 1px solid var(--rule);
}

.keytakeaway h3 {
  font-size: 1.02rem;
  margin-bottom: 7px;
}

.keytakeaway p {
  font-size: 0.93rem;
  color: var(--ink-2);
  line-height: 1.65;
}

/* 23 — Footer -------------------------------------------------------------- */

#site-footer {
  margin-top: clamp(30px, 3.8vw, 54px);
}

.site-footer {
  border-top: 1px solid var(--rule);
  padding-block: clamp(28px, 3.5vw, 42px) 20px;
  background: var(--bg);
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(2, minmax(0, 0.75fr));
  gap: clamp(28px, 4vw, 64px);
}

.footer-about .brand {
  margin-bottom: 16px;
}

.footer-about p {
  color: var(--ink-3);
  font-size: 0.88rem;
  line-height: 1.7;
  max-width: 44ch;
}

.footer-title {
  font-family: var(--font-sans);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 14px;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.footer-links a {
  font-family: var(--font-sans);
  font-size: 12.5px;
  color: var(--ink-2);
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 0.16em;
}

.footer-links .ext {
  font-size: 9px;
  color: var(--ink-3);
  margin-left: 2px;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px 24px;
  margin-top: clamp(20px, 2.4vw, 30px);
  padding-top: 14px;
  border-top: 1px solid var(--rule);
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.02em;
  color: var(--ink-3);
}

.footer-bottom a {
  color: var(--ink-3);
  text-decoration: none;
}

.footer-bottom a:hover {
  color: var(--ink-2);
  text-decoration: underline;
}

/* 24 — Toast --------------------------------------------------------------- */

.toast {
  position: fixed;
  left: 50%;
  bottom: 28px;
  z-index: 400;
  transform: translate(-50%, 12px);
  padding: 10px 18px;
  background: var(--ink);
  color: var(--bg);
  font-family: var(--font-sans);
  font-size: 12px;
  letter-spacing: 0.03em;
  border-radius: 999px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease);
}

.toast.is-visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

/* 24b — Paper microsite ---------------------------------------------------- */

.paper-hero {
  padding-block: clamp(38px, 5vw, 64px) 0;
}

.paper-hero .eyebrow {
  margin-bottom: 14px;
}

.paper-venue {
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-3);
}

.paper-title {
  font-family: var(--font-serif);
  font-size: clamp(2.1rem, 4.2vw, 3.35rem);
  font-weight: 500;
  line-height: 1.07;
  letter-spacing: -0.022em;
  max-width: 23ch;
  margin-top: 14px;
}

html[lang="zh-CN"] .paper-title {
  letter-spacing: 0;
  line-height: 1.18;
}

.paper-subtitle {
  margin-top: 12px;
  font-family: var(--font-serif);
  font-size: clamp(1rem, 1.4vw, 1.15rem);
  line-height: 1.55;
  color: var(--ink-2);
  max-width: 56ch;
}

.paper-hero .paper-authors {
  margin-top: 24px;
}

.paper-hero .paper-affiliations {
  margin-top: 10px;
}

.paper-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

.paper-teaser {
  margin: clamp(24px, 3.4vw, 40px) 0 0;
}

.paper-teaser .figure-img {
  padding: 0;
  background: #ffffff;
}

.paper-teaser figcaption {
  margin-top: 10px;
}

.paper-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  margin-top: clamp(22px, 3vw, 32px);
}

.paper-strip-item {
  padding: clamp(13px, 1.8vw, 20px) clamp(12px, 1.6vw, 20px);
  border-right: 1px solid var(--rule);
}

.paper-strip-item:last-child {
  border-right: 0;
}

.paper-strip-value {
  font-family: var(--font-serif);
  font-size: clamp(1.3rem, 2vw, 1.7rem);
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: -0.012em;
}

.paper-strip-label {
  margin-top: 5px;
  font-family: var(--font-sans);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--ink-3);
  line-height: 1.4;
}

.paper-body {
  padding-block: clamp(24px, 3.4vw, 44px) 0;
}

.paper-section {
  display: grid;
  grid-template-columns: 168px minmax(0, 1fr);
  gap: clamp(16px, 2.6vw, 42px);
  padding-block: clamp(24px, 3.2vw, 40px);
  border-top: 1px solid var(--rule);
}

.paper-rail {
  font-family: var(--font-sans);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.1em;
  line-height: 1.6;
  text-transform: uppercase;
  color: var(--ink-3);
}

.paper-rail .paper-num {
  display: block;
  margin-bottom: 5px;
  font-weight: 600;
  color: var(--warm);
}

.paper-content {
  min-width: 0;
}

.paper-content h2 {
  max-width: 26ch;
  font-size: clamp(1.45rem, 2.2vw, 1.9rem);
  letter-spacing: -0.014em;
}

.paper-content .lede {
  margin-top: 10px;
}

.paper-content p + p {
  margin-top: 0.85em;
}

.paper-content > .figure,
.paper-content > .figure-row,
.paper-content > .table-wrap,
.paper-content > .abstract-box,
.paper-content > .callout,
.paper-content > .keytakeaways,
.paper-content > .stats {
  margin-top: clamp(16px, 2.2vw, 26px);
}

.paper-abstract {
  font-size: clamp(1.02rem, 1.35vw, 1.1rem);
  line-height: 1.72;
  color: var(--ink-2);
  max-width: 72ch;
}

.paper-abstract p + p {
  margin-top: 0.9em;
}

.paper-abstract strong {
  color: var(--ink);
  font-weight: 600;
}

.paper-content .btn-row {
  margin-top: 18px;
}

@media (max-width: 900px) {
  .paper-section {
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
  }

  .paper-rail .paper-num {
    display: inline;
    margin-right: 8px;
  }

  .paper-strip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .paper-strip-item:nth-child(2) {
    border-right: 0;
  }

  .paper-strip-item:nth-child(-n + 2) {
    border-bottom: 1px solid var(--rule);
  }

  .paper-hero .paper-authors {
    gap: 6px 18px;
  }
}

/* 25 — Utilities ----------------------------------------------------------- */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.mt-0 {
  margin-top: 0;
}

.mt-sm {
  margin-top: 12px;
}

.mt {
  margin-top: 24px;
}

.mt-lg {
  margin-top: 32px;
}

.mb-lg {
  margin-bottom: 40px;
}

.hide {
  display: none !important;
}

.only-mobile {
  display: none;
}

.ext-arrow {
  font-size: 0.8em;
  vertical-align: 1px;
  color: var(--ink-3);
}

/* 26 — Motion -------------------------------------------------------------- */

@keyframes rise-in {
  from {
    opacity: 0;
    transform: translateY(14px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.hero .eyebrow,
.hero .display,
.hero-lede,
.hero-actions,
.hero-meta {
  animation: rise-in 0.85s var(--ease) both;
}

.hero .display {
  animation-delay: 0.06s;
}

.hero-lede {
  animation-delay: 0.14s;
}

.hero-actions {
  animation-delay: 0.2s;
}

.hero-meta {
  animation-delay: 0.28s;
}

.will-reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  will-change: opacity, transform;
}

.will-reveal.is-visible {
  opacity: 1;
  transform: none;
  will-change: auto;
}

.will-reveal-group > * {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.65s var(--ease), transform 0.65s var(--ease);
}

.will-reveal-group.is-visible > * {
  opacity: 1;
  transform: none;
}

.will-reveal-group.is-visible > *:nth-child(2) {
  transition-delay: 0.06s;
}

.will-reveal-group.is-visible > *:nth-child(3) {
  transition-delay: 0.12s;
}

.will-reveal-group.is-visible > *:nth-child(4) {
  transition-delay: 0.18s;
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-delay: 0ms !important;
    transition-duration: 0.001ms !important;
  }

  .will-reveal,
  .will-reveal-group > * {
    opacity: 1;
    transform: none;
  }
}

/* 27 — Responsive ---------------------------------------------------------- */

@media (max-width: 980px) {
  .grid--feature,
  .feature {
    grid-template-columns: minmax(0, 1fr);
  }

  .feature-media {
    order: 2;
  }

  .feature-body {
    order: 1;
  }

  .footer-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .footer-about {
    grid-column: 1 / -1;
  }
}

@media (max-width: 760px) {
  body {
    font-size: 16px;
  }

  .grid--2,
  .grid--3,
  .index-grid,
  .people-grid,
  .service-grid,
  .figure-row,
  .keytakeaways {
    grid-template-columns: minmax(0, 1fr);
  }

  .work-row {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .index-grid .index-item:nth-last-child(-n + 2) {
    border-bottom: 0;
  }

  .index-grid .index-item:last-child {
    border-bottom: 1px solid var(--rule);
  }

  .stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .stat:nth-child(2) {
    border-right: 0;
  }

  .stat:nth-child(-n + 2) {
    border-bottom: 1px solid var(--rule);
  }

  .news-item,
  .news-item--plain {
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
  }

  .news-tags {
    justify-content: flex-start;
  }

  .pub-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
  }

  .pub-year {
    padding-top: 0;
  }

  .patent-item {
    grid-template-columns: minmax(0, 1fr);
    gap: 10px;
  }

  .profile {
    grid-template-columns: minmax(0, 1fr);
  }

  .profile-figure {
    max-width: 260px;
  }

  .profile-hero {
    grid-template-columns: minmax(0, 1fr);
    gap: 26px;
  }

  .profile-hero .profile-figure {
    max-width: 240px;
  }

  .info-item {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
  }

  .section-head {
    grid-template-columns: minmax(0, 1fr);
  }

  .section-head > .link-arrow {
    padding-bottom: 0;
  }

  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .only-mobile {
    display: block;
  }

  .hide-mobile {
    display: none !important;
  }

  .display {
    letter-spacing: -0.02em;
  }

  .bibtex pre {
    padding-right: 0;
    white-space: pre-wrap;
    overflow-wrap: anywhere;
    word-break: break-word;
  }

  .bibtex .copy-btn {
    position: static;
    margin-top: 12px;
  }

  .table-wrap {
    -webkit-overflow-scrolling: touch;
  }

  .table-wrap table {
    font-size: 11.5px;
  }

  .table-wrap thead th,
  .table-wrap tbody td {
    padding: 9px 11px;
  }
}

@media (max-width: 520px) {
  .hero-actions .btn {
    width: 100%;
  }

  .feature-metrics {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 10px;
  }

  .filter-btn {
    padding: 6px 11px;
    font-size: 11px;
  }

  .brand-name {
    font-size: 0.98rem;
  }

  .brand-mark {
    width: 26px;
    height: 26px;
  }
}

/* 28 — Print --------------------------------------------------------------- */

@media print {
  :root {
    --bg: #ffffff;
    --ink: #111111;
    --ink-2: #333333;
    --ink-3: #555555;
    --rule: #dddddd;
  }

  .site-header,
  .site-footer,
  .filter-bar,
  .hero-actions,
  .pub-links,
  .theme-toggle,
  .lang-switch,
  .play {
    display: none !important;
  }

  body {
    font-size: 11pt;
  }

  .section {
    padding-block: 18pt;
  }

  a[href^="http"]::after {
    content: " (" attr(href) ")";
    font-size: 8pt;
    color: #666;
  }
}