/* ============================================================
   Zhixin Lu — personal academic website
   Palette inspired by the golden Möbius-strip "AI for Dynamics" logo
   ============================================================ */
:root {
  --bg:        #121622;
  --bg-soft:   #1a1f2c;
  --card:      #1e2433;
  --border:    #303b56;
  --fg:        #eceef4;
  --muted:     #a7b0c6;
  --gold:      #e5a83b;
  --gold-soft: #f3c76b;
  --teal:      #34d1c0;
  --link:      #8bdcff;
  --maxw:      1000px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "Inter", "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- Navbar ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(18, 22, 34, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 62px;
}
.nav .brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 700; color: var(--fg); font-size: 16px;
}
.nav .brand img { height: 36px; width: 36px; border-radius: 50%; object-fit: cover; }
.nav .brand:hover { text-decoration: none; }
.nav .links { display: flex; gap: 22px; flex-wrap: wrap; }
.nav .links a {
  color: var(--muted); font-size: 14px; font-weight: 500;
  padding: 4px 0; border-bottom: 2px solid transparent;
}
.nav .links a:hover,
.nav .links a.active {
  color: var(--gold-soft); border-bottom-color: var(--gold);
  text-decoration: none;
}

/* ---------- Hero ---------- */
.hero {
  background:
    radial-gradient(1200px 400px at 80% -10%, rgba(229,168,59,0.20), transparent 60%),
    radial-gradient(900px 500px at 10% 10%, rgba(52,209,192,0.10), transparent 60%),
    linear-gradient(180deg, #161b2b 0%, var(--bg) 100%);
  border-bottom: 1px solid var(--border);
  padding: 64px 0 56px;
}
.hero .container {
  display: grid; grid-template-columns: 1fr 300px;
  gap: 40px; align-items: center;
}
.hero h1 { font-size: 40px; letter-spacing: -0.5px; line-height: 1.15; }
.hero .role { color: var(--gold-soft); font-weight: 600; margin-top: 6px; font-size: 18px; }
.hero .affil { color: var(--muted); font-size: 15px; margin-top: 2px; }
.hero p.lede { margin-top: 18px; color: var(--fg); font-size: 16px; max-width: 620px; }
.hero .logo-wrap { text-align: center; }
.hero .logo-wrap img {
  width: 100%; max-width: 320px; height: auto;
  /* The PNG has a pure-black background; "screen" drops the black so only
     the gold Möbius glow shows, blending it into the page. */
  mix-blend-mode: screen;
  filter: drop-shadow(0 0 45px rgba(229,168,59,0.30));
}
.hero .cta { margin-top: 22px; display: flex; gap: 12px; flex-wrap: wrap; }
.btn {
  display: inline-block; padding: 9px 18px; border-radius: 8px;
  font-size: 14px; font-weight: 600; border: 1px solid var(--border);
}
.btn.primary { background: linear-gradient(135deg, var(--gold), #c9862a); color: #1a1205; border: none; }
.btn.primary:hover { text-decoration: none; filter: brightness(1.07); }
.btn.ghost { background: transparent; color: var(--fg); }
.btn.ghost:hover { text-decoration: none; border-color: var(--gold); color: var(--gold-soft); }

/* ---------- Sections ---------- */
section.block { padding: 48px 0; border-bottom: 1px solid var(--border); }
h2.section-title {
  font-size: 26px; margin-bottom: 8px;
}
h2.section-title .accent { color: var(--gold); }
.section-sub { color: var(--muted); margin-bottom: 24px; }

/* ---------- Cards ---------- */
.cards { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 12px; padding: 22px;
}
.card h3 { color: var(--gold-soft); font-size: 18px; margin-bottom: 8px; }
.card p { color: var(--muted); font-size: 15px; }

/* ---------- Publications ---------- */
.pub-list { list-style: none; }
.pub-item {
  padding: 16px 0; border-bottom: 1px solid var(--border);
  display: grid; grid-template-columns: 60px 1fr; gap: 16px;
}
.pub-item:last-child { border-bottom: none; }
.pub-year { color: var(--gold); font-weight: 700; font-size: 15px; }
.pub-title { color: var(--fg); font-weight: 600; }
.pub-authors { color: var(--muted); font-size: 14px; }
.pub-venue { color: var(--teal); font-size: 14px; font-style: italic; }
.tag {
  display: inline-block; font-size: 11px; font-weight: 700; letter-spacing: .5px;
  padding: 2px 8px; border-radius: 20px; margin-left: 8px;
  background: rgba(229,168,59,0.15); color: var(--gold-soft);
  border: 1px solid rgba(229,168,59,0.3);
}

/* ---------- Blog ---------- */
.post-card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 12px; padding: 24px; margin-bottom: 20px;
  transition: border-color .2s;
}
.post-card:hover { border-color: var(--gold); }
.post-card h3 { font-size: 20px; margin-bottom: 6px; }
.post-card h3 a { color: var(--fg); }
.post-card .meta { color: var(--muted); font-size: 13px; margin-bottom: 10px; }
.post-card .meta .venue { color: var(--gold-soft); font-weight: 600; }
.post-card p { color: var(--muted); font-size: 15px; }

/* ---------- Prose (CV / blog body) ---------- */
.prose { max-width: 820px; }
.prose h3 { color: var(--gold-soft); margin: 28px 0 10px; font-size: 20px; }
.prose ul { margin: 8px 0 16px 22px; }
.prose li { margin-bottom: 6px; color: var(--fg); }
.prose .muted { color: var(--muted); }
.prose .row { display: flex; justify-content: space-between; gap: 16px; }
.prose .row .right { color: var(--muted); white-space: nowrap; }

/* ---------- Banner (blog post) ---------- */
.talk-banner {
  background: linear-gradient(135deg, #1a1205, #2a1e08);
  border: 1px solid rgba(229,168,59,0.4);
  border-radius: 12px; padding: 20px 24px; margin: 24px 0;
}
.talk-banner .venue { color: var(--gold-soft); font-weight: 700; }
.talk-banner .date { color: var(--muted); }

.embed-frame {
  width: 100%; height: 80vh; border: 1px solid var(--border);
  border-radius: 12px; background: #fff;
}

/* ---------- Footer ---------- */
footer {
  padding: 30px 0; color: var(--muted); font-size: 14px; text-align: center;
}
footer a { color: var(--gold-soft); }

/* ---------- Responsive ---------- */
@media (max-width: 760px) {
  .hero .container { grid-template-columns: 1fr; text-align: center; }
  .hero .logo-wrap { order: -1; }
  .hero .logo-wrap img { width: 150px; height: 150px; }
  .hero .cta { justify-content: center; }
  .cards { grid-template-columns: 1fr; }
  .nav .links { gap: 14px; }
  .hero h1 { font-size: 30px; }
}

/* Research program, October 2026 */
:root {
  --bg: #0d1119;
  --bg-soft: #141a24;
  --card: #171e2a;
  --border: #2a3444;
  --fg: #f1f0ec;
  --muted: #b0bacb;
  --gold: #e7b65d;
  --gold-soft: #f0ca87;
  --maxw: 1240px;
}
html { scroll-padding-top: 92px; }
body { overflow-wrap: break-word; }
img { max-width: 100%; }
a, button { -webkit-tap-highlight-color: rgba(231,182,93,.2); }
a:focus-visible, button:focus-visible, summary:focus-visible { outline: 2px solid var(--gold-soft); outline-offset: 5px; }
.skip-link { position: fixed; z-index: 100; top: 8px; left: 16px; padding: 10px 16px; background: var(--fg); color: var(--bg); transform: translateY(-160%); }
.skip-link:focus { transform: translateY(0); }
.nav { background: rgba(13,17,25,.94); }
.nav .container { height: 76px; }
.nav .brand { font-size: 18px; letter-spacing: -.35px; white-space: nowrap; }
.nav .links { gap: 26px; }
.nav .links a { font-size: 13px; padding: 8px 0; }
.eyebrow { color: var(--gold-soft); font-size: 10px; font-weight: 650; letter-spacing: .16em; text-transform: uppercase; line-height: 1.6; }
.eyebrow span { color: var(--muted); margin: 0 6px; }
.hero { background: radial-gradient(ellipse at 80% 35%, rgba(157,102,20,.08), transparent 60%), var(--bg); }
.home-hero { padding: 72px 0 64px; overflow: hidden; }
.home-hero .container { grid-template-columns: minmax(0, .95fr) minmax(0, 1.2fr); gap: 38px; }
.home-hero h1, .research-hero h1 { font-family: Georgia, 'Times New Roman', serif; font-size: clamp(36px,4.35vw,56px); font-weight: 400; letter-spacing: -1.7px; line-height: 1.13; margin: 20px 0 24px; }
.home-hero h1 em, .research-hero h1 em, .editorial-title em { color: var(--gold-soft); font-weight: 400; }
.home-hero p.lede { font-size: 20px; line-height: 1.55; max-width: 440px; margin-top: 0; }
.hero-intro { color: var(--muted); font-size: 15px; line-height: 1.85; margin-top: 18px; max-width: 445px; }
.hero-intro strong { color: var(--fg); font-weight: 500; }
.home-hero .cta { margin-top: 28px; }
.cta { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.btn { border-radius: 5px; padding: 11px 18px; font-size: 13px; }
.btn.primary { background: var(--gold-soft); color: #1b1509; }
.btn span { margin-left: 9px; }
.program-art { width: 100%; position: relative; }
.figure-zoom { display: block; position: relative; padding-bottom: 26px; border-radius: 8px; }
.program-art picture { display: block; }
.program-art img { display: block; width: 100%; height: auto; mix-blend-mode: normal; }
.program-art figcaption { text-align: center; font-size: 11px; letter-spacing: .1em; text-transform: uppercase; color: var(--muted); margin-top: 14px; }
.zoom-label { position: absolute; bottom: 0; right: 8px; color: var(--gold-soft); font-size: 11px; border-bottom: 1px solid #6e5835; padding: 3px 0; }
.figure-zoom:hover { text-decoration: none; }
.figure-zoom:hover .zoom-label { color: var(--fg); border-color: var(--fg); }
.updates { padding: 27px 0 33px; border-bottom: 1px solid var(--border); background: #111722; }
.updates h2 { color: var(--muted); margin-bottom: 20px; font-weight: 500; }
.updates h2 span { margin-left: 8px; color: #818fa4; }
.updates-grid { display: grid; grid-template-columns: 1.2fr 1fr 1fr; }
.update-item { display: flex; align-items: flex-start; flex-direction: column; padding: 0 30px; border-left: 1px solid var(--border); color: var(--fg); }
.update-item:first-child { padding-left: 0; border: 0; }
.update-item:last-child { padding-right: 0; }
.update-item:hover { text-decoration: none; }
.update-item:hover strong { color: var(--gold-soft); }
.update-item strong { font-size: 15px; font-weight: 500; line-height: 1.5; margin: 9px 0; max-width: 320px; }
.status { display: inline-block; color: var(--gold-soft); font-size: 10px; font-weight: 600; letter-spacing: .1em; text-transform: uppercase; line-height: 1.7; }
.status-teal { color: #87d6c8; }
.status-muted { color: #b4c1d7; }
.update-detail { color: var(--muted); font-size: 12px; margin-top: auto; }
.update-detail span { margin-left: 6px; color: var(--gold); }
section.block { padding: 72px 0; }
.editorial-title { font: 400 38px/1.22 Georgia, 'Times New Roman', serif; letter-spacing: -.7px; margin: 12px 0 20px; }
.section-heading .section-sub { max-width: 680px; margin-top: 18px; }
.section-sub { font-size: 15px; }
.direction-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; margin-top: 34px; }
.direction { border-top: 1px solid #6f5938; padding-top: 20px; }
.direction-index { font-size: 10px; color: var(--gold-soft); letter-spacing: .15em; text-transform: uppercase; }
.direction-index span { color: #758399; margin: 0 9px; }
.direction h3 { font-size: 25px; font-weight: 500; letter-spacing: -.6px; margin: 13px 0 14px; }
.direction p { font-size: 15px; color: var(--muted); max-width: 515px; }
.text-link { display: inline-block; color: var(--gold-soft); font-size: 13px; }
.direction .text-link { margin-top: 20px; }
.physical-interest { display: grid; grid-template-columns: 1fr 1.45fr; gap: 48px; margin-top: 42px; padding: 30px 34px; border-left: 2px solid var(--gold); background: #151c25; }
.physical-interest h3 { font: 400 29px/1.25 Georgia, 'Times New Roman', serif; margin-top: 10px; }
.physical-interest p:not(.eyebrow) { color: var(--muted); font-size: 15px; }
.physical-interest .text-link { margin-top: 12px; }
.paper-section { background: #111722; }
.featured-paper { display: grid; grid-template-columns: .85fr 1.15fr; gap: 80px; align-items: center; }
.paper-question { padding-right: 5px; }
.big-question { font: 400 46px/1.16 Georgia, 'Times New Roman', serif; letter-spacing: -.9px; margin-top: 25px; }
.big-question em { color: var(--gold-soft); }
.time-directions { display: flex; align-items: center; gap: 15px; margin: 32px 0 14px; color: #abb9ce; font-size: 9px; letter-spacing: .15em; }
.time-line { height: 1px; flex: 1; background: linear-gradient(90deg,#40516b,var(--gold)); position: relative; }
.time-line::after { content: ''; width: 7px; height: 7px; border-top: 1px solid var(--gold); border-right: 1px solid var(--gold); position: absolute; right: 0; top: -3px; transform: rotate(45deg); }
.question-caption { color: var(--muted); font-size: 11px; }
.paper-copy h2 { font-size: 27px; line-height: 1.3; letter-spacing: -.7px; font-weight: 500; margin: 12px 0; }
.paper-copy p { font-size: 14px; color: var(--muted); margin: 14px 0; }
.paper-copy .paper-author { font-size: 12px; margin-bottom: 24px; }
.paper-copy .cta { margin-top: 26px; }
.about-grid { display: grid; grid-template-columns: 1fr 1.65fr; gap: 70px; }
.about-copy p { color: var(--muted); font-size: 15px; margin-bottom: 16px; }
.about-copy strong { color: var(--fg); font-weight: 500; }
.inline-links { display: flex; flex-wrap: wrap; gap: 24px; margin-top: 24px; font-size: 13px; }
.inline-links a { color: var(--gold-soft); }
.writing-heading { display: flex; justify-content: space-between; align-items: end; gap: 20px; }
.writing-heading .editorial-title { margin-bottom: 10px; }
.writing-heading > a { margin-bottom: 15px; }
.post-card { border-radius: 6px; background: #141b25; padding: 26px; }
.post-card .eyebrow { color: var(--gold-soft); font-size: 10px; margin-bottom: 14px; }
.post-card h3 { font-size: 19px; font-weight: 500; line-height: 1.45; margin-bottom: 12px; }
.post-card h3 span { color: var(--gold); }
footer { font-size: 12px; padding: 30px 0; }
.figure-dialog { width: min(1120px,94vw); max-height: 94vh; margin: auto; border: 1px solid #6d5635; border-radius: 8px; padding: 20px; background: #0b0e13; color: var(--fg); overflow: auto; }
.figure-dialog::backdrop { background: rgba(0,0,0,.88); backdrop-filter: blur(5px); }
.dialog-heading { display: flex; justify-content: space-between; align-items: center; gap: 20px; margin-bottom: 16px; }
.dialog-heading h2 { font-size: 15px; font-weight: 500; }
.dialog-heading button { border: 1px solid var(--border); border-radius: 4px; background: #19212e; color: var(--fg); font: inherit; font-size: 13px; padding: 8px 12px; cursor: pointer; white-space: nowrap; }
.figure-dialog img { display: block; width: 100%; height: auto; max-height: 72vh; object-fit: contain; }
.figure-dialog > p { font-size: 12px; color: var(--muted); max-width: 820px; margin-top: 14px; }
body:has(.figure-dialog[open]) { overflow: hidden; }
.research-hero .container { grid-template-columns: 1fr; }
.research-hero p.lede { max-width: 790px; color: var(--muted); }
.research-hero { padding: 54px 0; }
.research-map { display: grid; grid-template-columns: 1.15fr 1fr; gap: 64px; align-items: center; }
.research-map img { width: 100%; height: auto; display: block; mix-blend-mode: normal; }
.research-map figcaption { font-size: 11px; color: var(--muted); text-align: center; margin-top: 15px; }
.research-map p:not(.eyebrow) { font-size: 14px; color: var(--muted); margin-top: 15px; }
.research-map .muted { font-size: 12px !important; }
.research-map strong { color: var(--fg); font-weight: 500; }
.research-lede { max-width: 760px; }
.research-topics { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 32px; margin-top: 32px; }
.research-topics article { border-top: 1px solid #4b5668; padding-top: 21px; }
.research-topics h3 { font-size: 20px; font-weight: 500; line-height: 1.4; margin-bottom: 14px; }
.research-topics p { color: var(--muted); font-size: 14px; }
.research-topics .text-link { margin-top: 18px; }
.research-topics .topic-feature { border-color: var(--gold); }
.topic-feature .status { margin-bottom: 8px; }
.physical-section { background: #141b25; }
.physical-research { display: grid; grid-template-columns: .85fr 1.5fr; gap: 80px; }
.physical-research p:not(.eyebrow) { font-size: 15px; color: var(--muted); margin-bottom: 18px; }
.physical-research p.research-question { font-size: 21px; line-height: 1.55; color: var(--fg); }
.pub-list { max-width: 1000px; }
.pub-item { padding: 23px 0; }
.pub-summary { color: var(--muted); font-size: 13px; margin-top: 8px; max-width: 750px; }
.pub-title > a { color: var(--fg); }
.pub-title > a:hover { color: var(--gold-soft); }
.pub-item:target { background: rgba(231,182,93,.06); outline: 1px solid rgba(231,182,93,.3); outline-offset: 12px; }

@media (max-width: 1000px) {
  .home-hero { padding-top: 48px; }
  .home-hero .container { gap: 24px; }
  .home-hero h1 { font-size: 43px; }
  .home-hero p.lede { font-size: 18px; }
  .hero-intro { font-size: 14px; }
  .featured-paper { gap: 46px; }
  .big-question { font-size: 39px; }
  .research-map { gap: 30px; }
  .research-topics { gap: 22px; }
}
@media (max-width: 800px) {
  .nav .container { min-height: 70px; height: auto; padding-top: 12px; padding-bottom: 12px; gap: 16px; flex-wrap: wrap; }
  .nav .links { gap: 19px; }
  .home-hero .container { grid-template-columns: 1fr; text-align: left; gap: 34px; }
  .home-hero .hero-copy { max-width: 590px; }
  .home-hero h1 { font-size: 50px; }
  .home-hero p.lede, .hero-intro { max-width: 560px; }
  .hero-intro { font-size: 15px; }
  .home-hero .cta { justify-content: flex-start; }
  .program-art { max-width: 660px; margin: 0 auto; }
  .home-hero { padding-bottom: 38px; }
  .program-art figcaption { margin-top: 8px; }
  .updates-grid { gap: 20px; grid-template-columns: repeat(3,minmax(0,1fr)); }
  .update-item { padding: 0 0 0 18px; }
  .update-item strong { font-size: 13px; }
  section.block { padding: 48px 0; }
  .editorial-title { font-size: 33px; }
  .direction-grid { gap: 30px; }
  .physical-interest { grid-template-columns: 1fr; gap: 16px; padding: 26px; }
  .featured-paper { grid-template-columns: 1fr; gap: 32px; }
  .paper-question { max-width: 570px; }
  .big-question { font-size: 39px; max-width: 480px; }
  .time-directions { max-width: 370px; }
  .about-grid { gap: 30px; grid-template-columns: 1fr 1.5fr; }
  .research-hero .container { text-align: left; }
  .research-map { grid-template-columns: 1fr; gap: 32px; }
  .research-map figure { max-width: 620px; }
  .research-topics { grid-template-columns: 1fr; gap: 30px; }
  .physical-research { grid-template-columns: 1fr; gap: 20px; }
}
@media (max-width: 540px) {
  html { scroll-padding-top: 122px; }
  .container { padding-left: 22px; padding-right: 22px; }
  .nav .container { gap: 5px; padding-top: 9px; padding-bottom: 8px; }
  .nav .brand { font-size: 16px; }
  .nav .brand img { height: 30px; width: 30px; }
  .nav .links { width: 100%; justify-content: space-between; gap: 8px; }
  .nav .links a { font-size: 12px; padding: 5px 0; }
  .home-hero { padding-top: 32px; }
  .home-hero h1, .research-hero h1 { font-size: clamp(30px,8.9vw,46px); letter-spacing: -1px; margin-top: 16px; }
  .home-hero p.lede { font-size: 18px; }
  .home-hero .eyebrow { font-size: 9px; letter-spacing: .1em; }
  .home-hero .cta { gap: 10px; }
  .btn { padding: 10px 14px; font-size: 12px; }
  .updates { padding: 24px 0; }
  .updates-grid { grid-template-columns: 1fr; gap: 18px; }
  .update-item { border-left: 0; padding: 17px 0 0; border-top: 1px solid var(--border); }
  .update-item:first-child { padding-top: 0; }
  .update-item strong { font-size: 15px; margin: 4px 0; max-width: none; }
  .editorial-title { font-size: 29px; }
  .direction-grid { grid-template-columns: 1fr; gap: 32px; }
  .direction h3 { font-size: 24px; }
  .physical-interest { padding: 23px; gap: 16px; }
  .physical-interest h3 { font-size: 27px; }
  .about-grid { grid-template-columns: 1fr; gap: 28px; }
  .big-question { font-size: 36px; }
  .paper-copy h2 { font-size: 25px; }
  .writing-heading { display: block; }
  .writing-heading > a { margin-bottom: 10px; }
  .pub-item { grid-template-columns: 42px minmax(0,1fr); gap: 10px; }
  .pub-title { font-size: 15px; }
  .tag { margin-left: 0; margin-top: 5px; }
  .figure-dialog { padding: 12px; }
  .dialog-heading h2 { font-size: 12px; }
  .prose .row { flex-wrap: wrap; gap: 3px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}
.talk-update { display: flex; align-items: baseline; flex-wrap: wrap; gap: 8px 22px; margin: 22px 0 0; padding-top: 18px; border-top: 1px solid var(--border); font-size: 12px; }
.talk-update > span { color: var(--muted); }
.talk-update > span:first-child { color: var(--gold-soft); }
.talk-update > a { color: var(--fg); }