/* ──────────────────────────────────────────────────────────────────────────
   WordPress / Twentytwentyfour theme overrides
   Keep these first — they neutralize the .is-layout-constrained 620px cap
   that the block theme imposes on Custom HTML content.
   ────────────────────────────────────────────────────────────────────────── */
.wp-site-blocks,
.wp-block-post-content,
.entry-content {
  max-width: none !important;
  padding-left: 0 !important;
  padding-right: 0 !important;
}

.is-layout-constrained > *,
.wp-block-post-content > * {
  max-width: none !important;
  margin-left: 0 !important;
  margin-right: 0 !important;
}

body {
  --wp--style--global--content-size: 100% !important;
  --wp--style--global--wide-size: 100% !important;
  --wp--style--root--padding-left: 0 !important;
  --wp--style--root--padding-right: 0 !important;
  padding: 0 !important;
  margin: 0 !important;
}

/* ──────────────────────────────────────────────────────────────────────────
   Design tokens
   ────────────────────────────────────────────────────────────────────────── */
:root {
  /* Surfaces — OpenAI-bright, faint warm hint */
  --cream:       #fcfcfa;
  --cream-2:     #f4f4f1;
  --cream-3:     #eaeae6;

  /* Ink + alpha overlays — near-pure black, OpenAI-style high contrast */
  --ink:         #0a0a0a;
  --ink-rgb:     10, 10, 10;
  --ink-04:      rgba(var(--ink-rgb), .04);
  --ink-08:      rgba(var(--ink-rgb), .08);
  --ink-12:      rgba(var(--ink-rgb), .12);
  --ink-24:      rgba(var(--ink-rgb), .24);
  --ink-44:      rgba(var(--ink-rgb), .44);
  --ink-60:      rgba(var(--ink-rgb), .60);
  --ink-80:      rgba(var(--ink-rgb), .80);

  /* Dark contexts */
  --dark-bg:           #0a0a0a;
  --cream-on-dark:     #fafafa;
  --cream-on-dark-rgb: 250, 250, 250;

  /* Accent palette — OpenAI-inspired (no single primary, used decoratively) */
  --rust:          #cc6f47;
  --rust-rgb:      204, 111, 71;
  --green:         #71b436;
  --green-rgb:     113, 180, 54;
  --blue:          #5477c4;
  --blue-rgb:      84, 119, 196;
  --peach:         #ffbda1;
  --peach-rgb:     255, 189, 161;
  --blue-pale:     #cedffe;
  --blue-pale-rgb: 206, 223, 254;

  /* Type families */
  --font-serif: 'Source Serif 4', Georgia, serif;
  --font-sans:  'Inter Tight', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;

  /* Type scale (clamped for smooth desktop ↔ mobile scaling) */
  --text-display-xxl: clamp(48px, 6.5vw, 96px);
  --text-display-xl:  clamp(40px, 5vw,   72px);
  --text-display-l:   clamp(32px, 4vw,   58px);
  --text-display-m:   clamp(24px, 2.8vw, 32px);
  --text-display-s:   20px;
  --text-display-xs:  18px;

  --text-paragraph-l: clamp(19px, 1.6vw, 22px);
  --text-paragraph-m: 17px;
  --text-paragraph-s: 15px;

  --text-meta:   14px;
  --text-cta:    14px;
  --text-label:  12px;
  --text-micro:  11px;

  /* Spacing scale (clamped) */
  --space-2xs: clamp(0.25rem, 0.2vw + 0.2rem, 0.5rem);
  --space-xs:  clamp(0.5rem,  0.4vw + 0.4rem, 1rem);
  --space-sm:  clamp(1rem,    0.6vw + 0.8rem, 1.5rem);
  --space-md:  clamp(1.5rem,  1vw   + 1.2rem, 2.5rem);
  --space-lg:  clamp(2.5rem,  2vw   + 1.5rem, 4rem);
  --space-xl:  clamp(4rem,    3vw   + 2.5rem, 6rem);
  --space-2xl: clamp(6rem,    4vw   + 4rem,   8rem);
  --space-3xl: clamp(8rem,    6vw   + 5rem,   12rem);

  /* Layout */
  --container-max:    1280px;
  --container-narrow: 640px;
  --container-mid:    960px;
  --gutter:           clamp(1rem, 2vw, 2rem);
  --section-pad-x:    clamp(1.5rem, 3vw, 2.5rem);
  --nav-h:            72px;

  /* Components */
  --radius-pill: 999px;
  --radius-md:   8px;
  --radius-sm:   4px;

  --border-hairline: 1px solid var(--ink-08);
  --border-light:    1px solid var(--ink-12);

  --transition-fast: 150ms cubic-bezier(.4, 0, .2, 1);
  --transition-base: 300ms cubic-bezier(.4, 0, .2, 1);
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--cream);
  color: var(--ink);
  font-family: var(--font-serif);
  font-size: var(--text-paragraph-m);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

::selection { background: rgba(var(--blue-rgb), .25); }

/* ──────────────────────────────────────────────────────────────────────────
   Typography utility classes
   ────────────────────────────────────────────────────────────────────────── */
.u-text-display-xxl {
  font-family: var(--font-serif);
  font-size: var(--text-display-xxl);
  font-weight: 400; line-height: 1.05;
  letter-spacing: -.025em;
  color: var(--ink);
}
.u-text-display-xl {
  font-family: var(--font-serif);
  font-size: var(--text-display-xl);
  font-weight: 400; line-height: 1.08;
  letter-spacing: -.025em;
  color: var(--ink);
}
.u-text-display-l {
  font-family: var(--font-serif);
  font-size: var(--text-display-l);
  font-weight: 400; line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--ink);
}
.u-text-display-m {
  font-family: var(--font-serif);
  font-size: var(--text-display-m);
  font-weight: 500; line-height: 1.2;
  letter-spacing: -.015em;
  color: var(--ink);
}
.u-text-display-s {
  font-family: var(--font-serif);
  font-size: var(--text-display-s);
  font-weight: 400; line-height: 1.25;
  color: var(--ink);
}
.u-text-display-xs {
  font-family: var(--font-serif);
  font-size: var(--text-display-xs);
  font-weight: 400; line-height: 1.3;
  color: var(--ink);
}

.u-text-paragraph-l {
  font-family: var(--font-serif);
  font-size: var(--text-paragraph-l);
  font-weight: 300; line-height: 1.6;
  color: var(--ink-60);
}
.u-text-paragraph-m {
  font-family: var(--font-serif);
  font-size: var(--text-paragraph-m);
  font-weight: 300; line-height: 1.75;
  color: var(--ink-60);
}
.u-text-paragraph-s {
  font-family: var(--font-serif);
  font-size: var(--text-paragraph-s);
  font-weight: 300; line-height: 1.7;
  color: var(--ink-60);
}

.u-text-meta {
  font-family: var(--font-sans);
  font-size: var(--text-meta);
  font-weight: 500; line-height: 1.5;
  color: var(--ink-44);
}
.u-text-cta {
  font-family: var(--font-sans);
  font-size: var(--text-cta);
  font-weight: 600; line-height: 1;
  letter-spacing: .01em;
}
.u-text-label {
  font-family: var(--font-sans);
  font-size: var(--text-label);
  font-weight: 600; line-height: 1.4;
  text-transform: uppercase;
  letter-spacing: .12em;
  color: var(--ink-44);
}
.u-text-label-accent { color: var(--rust); }
.u-text-label-cream  { color: rgba(var(--cream-on-dark-rgb), .55); }

.u-text-micro {
  font-family: var(--font-sans);
  font-size: var(--text-micro);
  font-weight: 500; line-height: 1.4;
  color: var(--ink-44);
}

/* Italic emphasis token for editorial headlines */
.u-italic { font-style: italic; }
.u-text-display-xxl em,
.u-text-display-xl em,
.u-text-display-l em,
.u-text-display-m em {
  font-style: italic;
  font-weight: 400;
  color: var(--ink-60);
}

/* ──────────────────────────────────────────────────────────────────────────
   Post tags — pill chips filled with the research-area accent color.
   Used on the homepage featured-research card, the research index post
   cards, and the post-page hero. Color cycle mirrors .spec-pip on the
   homepage specialties grid:
     AI/ML → rust   |  Economic Modeling → blue
     Math Modeling → green |  Quantitative Finance → peach
   Text is always ink — readable on every accent at this small size.
   ────────────────────────────────────────────────────────────────────────── */
.post-tag {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-sans);
  font-size: var(--text-micro);
  font-weight: 700;
  letter-spacing: .08em; text-transform: uppercase;
  padding: 4px 10px; border-radius: var(--radius-pill);
  background: var(--ink-08);   /* fallback if no tag-* class */
  color: var(--ink);
  border: 1px solid transparent;
}

.post-tag.tag-ai   { background: var(--rust); }
.post-tag.tag-econ { background: var(--blue); }
.post-tag.tag-math { background: var(--peach); }
.post-tag.tag-qfin { background: var(--green); }

/* ──────────────────────────────────────────────────────────────────────────
   Pill buttons
   ────────────────────────────────────────────────────────────────────────── */
.u-btn {
  display: inline-flex; align-items: center; gap: .5em;
  height: 44px; padding: 0 24px;
  border: none; border-radius: var(--radius-pill);
  font-family: var(--font-sans);
  font-size: var(--text-cta); font-weight: 600;
  letter-spacing: .01em; text-decoration: none;
  cursor: pointer;
  transition: background var(--transition-fast),
              color var(--transition-fast),
              border-color var(--transition-fast),
              transform var(--transition-fast);
}
.u-btn:hover { transform: translateY(-1px); }
.u-btn svg { width: 14px; height: 14px; flex-shrink: 0; }

.u-btn-primary {
  background: var(--ink);
  color: var(--cream-on-dark);
}
.u-btn-primary:hover { background: var(--ink-80); }

.u-btn-ghost {
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--ink-12);
}
.u-btn-ghost:hover {
  border-color: var(--ink);
  background: var(--ink-04);
}

.u-btn-on-dark {
  background: var(--cream-on-dark);
  color: var(--ink);
}
.u-btn-on-dark:hover { background: #fff; }

/* ──────────────────────────────────────────────────────────────────────────
   Nav (shared shell — page-specific stylesheets handle bg/scrolled state)
   ────────────────────────────────────────────────────────────────────────── */
.nav-logo {
  display: flex; align-items: center;
  text-decoration: none;
  flex-shrink: 0;
}

.nav-logo-svg {
  height: auto;
  width: 125px;
  color: var(--ink);
}

.nav-links {
  display: flex; align-items: center; gap: 32px; list-style: none;
}

.nav-links a {
  font-family: var(--font-sans);
  font-size: 16px;              /* was: var(--text-cta) — bumped from 14px, nav links only */
  font-weight: 500;
  color: var(--ink-60);
  text-decoration: none;
  letter-spacing: .01em;
  transition: color var(--transition-fast);
}

.nav-links a:hover { color: var(--ink); }

.nav-cta {
  font-family: var(--font-sans);
  font-size: var(--text-cta); font-weight: 600;
  background: var(--ink); color: var(--cream-on-dark) !important;
  padding: 10px 20px; border-radius: var(--radius-pill);
  letter-spacing: .01em;
  transition: background var(--transition-fast),
              transform var(--transition-fast) !important;
}

.nav-cta:hover { background: var(--ink-80) !important; transform: translateY(-1px); }

/* Client Login — outlined pill, distinct from the filled .nav-cta so the two
   right-side actions don't compete. Links to the (future) app sign-in. */
.nav-login {
  font-family: var(--font-sans);
  font-size: var(--text-cta); font-weight: 600;
  color: var(--ink) !important;
  background: transparent;
  padding: 10px 20px; border-radius: var(--radius-pill);
  border: 1.5px solid var(--ink);
  letter-spacing: .01em;
  transition: background var(--transition-fast),
              color var(--transition-fast),
              transform var(--transition-fast);
}

.nav-login:hover {
  background: var(--ink);
  color: var(--cream-on-dark) !important;
  transform: translateY(-1px);
}

/* Hamburger toggle */
.nav-toggle {
  display: none;
  background: none; border: none; cursor: pointer;
  padding: 10px;
  width: 44px; height: 44px;
  flex-direction: column; justify-content: center; align-items: center;
  gap: 5px;
  z-index: 310;
}

.nav-toggle-bar {
  display: block;
  width: 22px; height: 2px;
  background: var(--ink);
  border-radius: 2px;
  transition: transform .3s ease, opacity .2s ease;
  transform-origin: center;
}

.nav-toggle.is-open .nav-toggle-bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.is-open .nav-toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle.is-open .nav-toggle-bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

@keyframes pulse {
  0%,100% { opacity: 1; transform: scale(1); }
  50%     { opacity: .4; transform: scale(.7); }
}

/* ──────────────────────────────────────────────────────────────────────────
   Footer (shared)
   ────────────────────────────────────────────────────────────────────────── */
footer {
  background: var(--dark-bg);
  color: rgba(var(--cream-on-dark-rgb), .5);
  padding: var(--space-xl) var(--section-pad-x) var(--space-lg);
}

.footer-top {
  max-width: var(--container-max);
  margin: 0 auto;
  display: grid; grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid rgba(var(--cream-on-dark-rgb), .08);
  margin-bottom: var(--space-md);
}

.footer-tagline {
  font-family: var(--font-serif);
  font-size: var(--text-paragraph-s);
  font-weight: 300;
  max-width: 280px;
  line-height: 1.7;
}

.footer-cols { display: flex; gap: 64px; justify-content: flex-end; }

.footer-col h5 {
  font-family: var(--font-sans);
  font-size: var(--text-micro);
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: rgba(var(--cream-on-dark-rgb), .35);
  margin-bottom: 18px;
}

.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: 12px; }

.footer-col a {
  font-family: var(--font-serif);
  font-size: var(--text-paragraph-s);
  font-weight: 300;
  color: rgba(var(--cream-on-dark-rgb), .55);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-col a:hover { color: rgba(var(--cream-on-dark-rgb), .95); }

.footer-bottom {
  max-width: var(--container-max);
  margin: 0 auto;
  display: flex; justify-content: space-between; align-items: center;
}

.footer-copy {
  font-family: var(--font-sans);
  font-size: var(--text-micro);
  font-weight: 500;
  color: rgba(var(--cream-on-dark-rgb), .4);
  letter-spacing: .02em;
}

.footer-pips { display: flex; gap: 6px; }

.footer-pips span {
  width: 6px; height: 6px;
  border-radius: 50%;
  display: block;
  background: rgba(var(--cream-on-dark-rgb), .35);
}

.footer-pips :nth-child(1) { background: var(--rust); }
.footer-pips :nth-child(2) { background: var(--green); }
.footer-pips :nth-child(3) { background: var(--blue); }
.footer-pips :nth-child(4) { background: var(--peach); }

/* ──────────────────────────────────────────────────────────────────────────
   Scroll-reveal
   ────────────────────────────────────────────────────────────────────────── */
.reveal {
  opacity: 0; transform: translateY(20px);
  transition: opacity .7s cubic-bezier(.4, 0, .2, 1),
              transform .7s cubic-bezier(.4, 0, .2, 1);
}
.reveal.in { opacity: 1; transform: none; }

.d1 { transition-delay: .08s; }
.d2 { transition-delay: .16s; }
.d3 { transition-delay: .24s; }
.d4 { transition-delay: .32s; }

/* ──────────────────────────────────────────────────────────────────────────
   Mobile nav
   ────────────────────────────────────────────────────────────────────────── */
@media (max-width: 960px) {
  .nav-toggle { display: flex; }

  .nav-links {
    position: fixed;
    top: var(--nav-h); left: 0; right: 0;
    background: rgba(252, 252, 250, .98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 16px 24px 32px;
    border-bottom: var(--border-light);
    transform: translateY(-12px);
    opacity: 0;
    pointer-events: none;
    transition: opacity .25s ease, transform .25s ease;
    z-index: 290;
    max-height: calc(100vh - var(--nav-h));
    overflow-y: auto;
  }

  .nav-links.is-open {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
  }

  .nav-links li {
    list-style: none;
    border-bottom: 1px solid var(--ink-08);
  }
  .nav-links li:last-child { border-bottom: none; }

  .nav-links a {
    display: block;
    padding: 16px 4px;
    font-size: 16px;
    color: var(--ink);
  }

  .nav-links .nav-cta {
    margin-top: 16px;
    text-align: center;
    padding: 14px 20px !important;
  }

  .nav-links .nav-login {
    margin-top: 12px;
    text-align: center;
    padding: 14px 20px;
  }

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

@media (prefers-reduced-motion: reduce) {
  .marquee-track,
  .hero-tag-dot,
  .page-hero-tag-dot { animation: none; }

  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* ──────────────────────────────────────────────────────────────────────────
   Form submit status (shared by the contact + newsletter forms)
   Base lives here so both the home and research pages get it; the dark
   newsletter context overrides colors via .form-status--dark in css_research.
   ────────────────────────────────────────────────────────────────────────── */
.form-status {
  font-family: var(--font-sans);
  font-size: var(--text-micro);
  letter-spacing: .02em;
  line-height: 1.5;
  margin-top: 12px;
}
.form-status[hidden] { display: none; }
.form-status.is-success { color: var(--ink); font-weight: 700; }
.form-status.is-error   { color: var(--rust); font-weight: 600; }