/* =========================================================================
   oceanleaf — base stylesheet
   Stage 1: design tokens, base typography, nav, footer.
   ========================================================================= */

/* --- Design tokens ------------------------------------------------------ */
:root {
  /* Palette — strict black & white. */
  --color-bg: #000;
  --color-bg-elevated: #0a0a0a;
  --color-fg: #fff;
  --color-fg-muted: #b8b8b8;
  --color-fg-dim: #6f6f6f;
  --color-border: #222;
  --color-border-strong: #3a3a3a;

  /* Type. Inter is the intended display family; we ship a system fallback
     until self-hosted woff2 files are added to /fonts. */
  --font-sans: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;

  --fs-1: clamp(2.75rem, 6vw + 0.5rem, 5.5rem);   /* hero */
  --fs-2: clamp(2rem, 3.5vw + 0.5rem, 3.25rem);   /* section title */
  --fs-3: clamp(1.5rem, 1.5vw + 0.75rem, 2rem);   /* sub-section */
  --fs-4: 1.125rem;                                /* body+ */
  --fs-body: 1rem;
  --fs-small: 0.875rem;

  --lh-tight: 1.1;
  --lh-snug: 1.3;
  --lh-body: 1.65;

  /* Space scale (rem, 4-px increments after 1). */
  --sp-1: 0.25rem;
  --sp-2: 0.5rem;
  --sp-3: 0.75rem;
  --sp-4: 1rem;
  --sp-5: 1.5rem;
  --sp-6: 2rem;
  --sp-7: 3rem;
  --sp-8: 4.5rem;
  --sp-9: 6.5rem;
  --sp-10: 9rem;

  --container-max: 1200px;
  --container-pad: clamp(1rem, 3vw, 2rem);

  --nav-height: 4.5rem;
  --radius: 4px;

  --transition: 180ms ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 1rem);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-fg);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  font-feature-settings: "kern", "liga", "calt";
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

h1, h2, h3, h4, h5, h6 { margin: 0 0 var(--sp-4); line-height: var(--lh-tight); font-weight: 600; letter-spacing: -0.01em; }
h1 { font-size: var(--fs-1); line-height: var(--lh-tight); letter-spacing: -0.02em; font-weight: 700; }
h2 { font-size: var(--fs-2); }
h3 { font-size: var(--fs-3); line-height: var(--lh-snug); }

p { margin: 0 0 var(--sp-4); color: var(--color-fg-muted); }
p:last-child { margin-bottom: 0; }

a { color: var(--color-fg); text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 3px; transition: color var(--transition); }
a:hover, a:focus-visible { color: var(--color-fg-muted); }

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

::selection { background: var(--color-fg); color: var(--color-bg); }

/* --- Container ---------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

/* --- Header / nav ------------------------------------------------------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  background: rgba(0, 0, 0, 0.72);
  backdrop-filter: saturate(140%) blur(10px);
  -webkit-backdrop-filter: saturate(140%) blur(10px);
  border-bottom: 1px solid var(--color-border);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-height);
  gap: var(--sp-5);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-3);
  text-decoration: none;
  color: var(--color-fg);
}

.brand-logo { display: block; width: 40px; height: 40px; }
.brand-name { font-weight: 600; letter-spacing: 0.02em; font-size: 1.125rem; }

.site-nav .nav-menu {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  gap: clamp(1rem, 2.5vw, 2.25rem);
}

.nav-menu a {
  color: var(--color-fg-muted);
  text-decoration: none;
  font-size: var(--fs-small);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: var(--sp-2) 0;
  position: relative;
  transition: color var(--transition);
}

.nav-menu a:hover,
.nav-menu a:focus-visible { color: var(--color-fg); }

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

/* Hamburger — hidden on desktop, visible on small screens. */
.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius);
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
}

.nav-toggle-bar {
  display: block;
  width: 18px;
  height: 1.5px;
  background: var(--color-fg);
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

@media (max-width: 720px) {
  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition);
  }

  .site-nav.is-open { max-height: 60vh; }

  .nav-menu {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: var(--sp-4) var(--container-pad);
  }

  .nav-menu li { border-top: 1px solid var(--color-border); }
  .nav-menu li:first-child { border-top: 0; }
  .nav-menu a { display: block; padding: var(--sp-4) 0; }
  .nav-menu a[aria-current="page"]::after { display: none; }
}

/* --- Main / page padding ----------------------------------------------- */
main { padding-top: var(--nav-height); }

/* --- Eyebrow (small uppercase label) ----------------------------------- */
.eyebrow {
  display: inline-block;
  font-size: var(--fs-small);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-fg-dim);
  margin: 0 0 var(--sp-3);
}

/* --- Button ------------------------------------------------------------- */
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
  padding: 0.75rem 1.5rem;
  border: 1px solid var(--color-fg);
  color: var(--color-fg);
  background: transparent;
  text-decoration: none;
  font-size: var(--fs-small);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  font-weight: 500;
  transition: background var(--transition), color var(--transition), transform var(--transition);
  cursor: pointer;
}
.button:hover, .button:focus-visible {
  background: var(--color-fg);
  color: var(--color-bg);
}

/* --- Hero --------------------------------------------------------------- */
main.home { padding-top: 0; }
.hero {
  position: relative;
  isolation: isolate;
  min-height: clamp(560px, 92vh, 940px);
  display: flex;
  align-items: flex-end;
  overflow: hidden;
}
.hero-media,
.hero-overlay { position: absolute; inset: 0; z-index: -1; }
.hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}
.hero-overlay {
  background:
    linear-gradient(180deg, rgba(0,0,0,0.55) 0%, rgba(0,0,0,0.20) 30%, rgba(0,0,0,0.65) 80%, rgba(0,0,0,0.92) 100%);
}
.hero-content {
  padding-block: var(--sp-10) var(--sp-8);
  width: 100%;
}
.hero-title {
  margin: 0 0 var(--sp-4);
  font-size: clamp(3.5rem, 11vw, 8rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 0.95;
}
.hero-tagline {
  margin: 0;
  font-size: clamp(1.125rem, 1.5vw + 0.5rem, 1.5rem);
  max-width: 38rem;
  color: var(--color-fg);
  line-height: var(--lh-snug);
}

.hero-scroll {
  position: absolute;
  left: 50%;
  bottom: var(--sp-5);
  transform: translateX(-50%);
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-2);
  text-decoration: none;
  color: var(--color-fg-muted);
  font-size: 0.75rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  z-index: 1;
  transition: color var(--transition);
}
.hero-scroll:hover,
.hero-scroll:focus-visible { color: var(--color-fg); }
.hero-scroll-line {
  width: 1px;
  height: 36px;
  background: currentColor;
  animation: scrollHint 1800ms ease-in-out infinite;
  transform-origin: top;
}
@keyframes scrollHint {
  0%, 100% { transform: scaleY(0.4); opacity: 0.6; }
  50%      { transform: scaleY(1);   opacity: 1; }
}
@media (max-width: 520px) { .hero-scroll { display: none; } }

/* --- About -------------------------------------------------------------- */
.about {
  padding-block: var(--sp-9);
}
.about-grid {
  display: grid;
  grid-template-columns: 5fr 7fr;
  gap: clamp(var(--sp-5), 4vw, var(--sp-8));
  align-items: start;
}
.about-portrait img {
  width: 100%;
  aspect-ratio: 3 / 4;
  object-fit: cover;
}
.about-name {
  margin: 0 0 var(--sp-2);
  font-size: var(--fs-2);
}
.about-role {
  margin: 0 0 var(--sp-6);
  font-size: var(--fs-3);
  color: var(--color-fg);
  line-height: var(--lh-snug);
}
.about-prose p {
  max-width: 62ch;
  margin-bottom: var(--sp-4);
}
.about-prose p:last-child { margin-bottom: 0; }

.about-meta {
  margin: var(--sp-6) 0 var(--sp-5);
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: var(--sp-2) var(--sp-5);
  font-size: var(--fs-small);
  padding-block: var(--sp-5);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}
.about-meta dt {
  margin: 0;
  color: var(--color-fg-dim);
  letter-spacing: 0.2em;
  text-transform: uppercase;
}
.about-meta dd { margin: 0; }
.about-meta a { text-decoration: none; border-bottom: 1px solid var(--color-border-strong); }
.about-meta a:hover, .about-meta a:focus-visible { border-bottom-color: var(--color-fg); }

.about-social {
  list-style: none;
  padding: 0;
  margin: var(--sp-5) 0 0;
  display: flex;
  gap: var(--sp-3);
}
.about-social a {
  display: inline-flex;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border-strong);
  border-radius: 50%;
  color: var(--color-fg-muted);
  transition: color var(--transition), border-color var(--transition), background var(--transition);
}
.about-social a:hover,
.about-social a:focus-visible {
  color: var(--color-bg);
  background: var(--color-fg);
  border-color: var(--color-fg);
}

@media (max-width: 800px) {
  .about-grid { grid-template-columns: 1fr; }
  .about-portrait { max-width: 380px; }
}

/* --- Section head (shared) --------------------------------------------- */
.section-head {
  margin-bottom: var(--sp-7);
}
.section-head .eyebrow { margin-bottom: var(--sp-2); }
.section-title {
  margin: 0;
  font-size: var(--fs-2);
}

/* --- Explore tiles ----------------------------------------------------- */
.explore {
  padding-block: var(--sp-8) var(--sp-9);
  border-top: 1px solid var(--color-border);
}
.explore-tiles {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--sp-5);
}
.tile-link {
  display: block;
  color: var(--color-fg);
  text-decoration: none;
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: border-color var(--transition), transform var(--transition);
}
.tile-link:hover,
.tile-link:focus-visible {
  border-color: var(--color-fg);
}
.tile-figure {
  margin: 0;
  aspect-ratio: 4 / 3;
  overflow: hidden;
}
.tile-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 500ms ease;
}
.tile-link:hover .tile-figure img,
.tile-link:focus-visible .tile-figure img {
  transform: scale(1.05);
}
.tile-text {
  padding: var(--sp-5);
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--sp-4);
}
.tile-text h3 {
  margin: 0 0 var(--sp-2);
  font-size: var(--fs-3);
  letter-spacing: -0.01em;
}
.tile-text p {
  margin: 0;
  color: var(--color-fg-muted);
  font-size: var(--fs-small);
}
.tile-arrow {
  font-size: 1.4rem;
  flex-shrink: 0;
  color: var(--color-fg-muted);
  transition: transform var(--transition), color var(--transition);
}
.tile-link:hover .tile-arrow,
.tile-link:focus-visible .tile-arrow {
  color: var(--color-fg);
  transform: translateX(4px);
}

/* --- Academia page ----------------------------------------------------- */
main.academia { padding-top: 0; }

.hero-academia { min-height: clamp(480px, 78vh, 720px); }
.hero-academia .hero-content { padding-block: var(--sp-10) var(--sp-9); }
.hero-academia .hero-title { font-size: clamp(2.75rem, 7vw, 5rem); letter-spacing: -0.03em; }
.hero-academia .hero-tagline { max-width: 44rem; color: var(--color-fg-muted); }

.hero-actions { margin: var(--sp-6) 0 0; }
.hero-cta { background: rgba(0, 0, 0, 0.35); backdrop-filter: blur(4px); -webkit-backdrop-filter: blur(4px); }

.research-section {
  padding-block: var(--sp-9);
  border-top: 1px solid var(--color-border);
}
.research-section--alt { background: var(--color-bg-elevated); }

.section-intro {
  display: grid;
  grid-template-columns: 6fr 5fr;
  gap: clamp(var(--sp-5), 4vw, var(--sp-8));
  align-items: center;
  margin-bottom: var(--sp-8);
}
.section-intro--reversed { grid-template-columns: 5fr 6fr; }
.section-intro--reversed .section-figure { order: 2; }
.section-figure {
  margin: 0;
  aspect-ratio: 3 / 2;
  overflow: hidden;
  border: 1px solid var(--color-border);
}
.section-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.section-text h2 { margin: 0 0 var(--sp-4); }
.section-text p { max-width: 56ch; }
.section-tagline {
  color: var(--color-fg-muted);
  font-size: clamp(1.125rem, 1vw + 0.625rem, 1.375rem);
  line-height: var(--lh-snug);
  margin: 0 0 var(--sp-4);
  max-width: 56ch;
}

/* --- Exploration hub bullets ------------------------------------------- */
.hub-bullets {
  list-style: none;
  margin: 0 0 var(--sp-6);
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--sp-4);
}
.hub-bullets li {
  color: var(--color-fg-muted);
  line-height: var(--lh-snug);
}
.hub-bullets li strong {
  color: var(--color-fg);
  font-weight: 600;
}
.section-text .hub-bullets + .hub-actions {
  margin: 0;
}

.subsection-title {
  margin: 0 0 var(--sp-5);
  font-size: var(--fs-3);
  letter-spacing: -0.01em;
}

.publications { margin-bottom: var(--sp-8); }
.publications:last-child { margin-bottom: 0; }

.pub-grid {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--sp-5);
}

.pub-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  color: var(--color-fg);
  text-decoration: none;
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: border-color var(--transition), transform var(--transition);
}
.research-section--alt .pub-card { background: var(--color-bg); }
.pub-card:hover,
.pub-card:focus-visible {
  border-color: var(--color-fg);
}
.pub-thumb {
  margin: 0;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  border-bottom: 1px solid var(--color-border);
}
.pub-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 500ms ease;
}
.pub-card:hover .pub-thumb img,
.pub-card:focus-visible .pub-thumb img {
  transform: scale(1.05);
}
.pub-body {
  padding: var(--sp-5);
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
  flex: 1;
}
.pub-title {
  margin: 0;
  font-size: var(--fs-4);
  line-height: var(--lh-snug);
  letter-spacing: -0.005em;
  font-weight: 600;
}
.pub-authors {
  margin: 0;
  font-size: var(--fs-small);
  color: var(--color-fg-muted);
  line-height: var(--lh-snug);
}
.pub-meta {
  margin: auto 0 0;
  font-size: var(--fs-small);
  color: var(--color-fg-dim);
  letter-spacing: 0.04em;
}

.press { margin-top: var(--sp-7); }
.press-row {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--sp-4);
}
.press-card {
  display: block;
  padding: var(--sp-5);
  color: var(--color-fg);
  text-decoration: none;
  border: 1px solid var(--color-border);
  transition: border-color var(--transition), background var(--transition);
}
.press-card:hover,
.press-card:focus-visible {
  border-color: var(--color-fg);
  background: var(--color-bg-elevated);
}
.research-section--alt .press-card:hover,
.research-section--alt .press-card:focus-visible {
  background: var(--color-bg);
}
.press-outlet {
  margin: 0 0 var(--sp-2);
  font-size: var(--fs-small);
  color: var(--color-fg-dim);
  letter-spacing: 0.16em;
  text-transform: uppercase;
}
.press-headline {
  margin: 0;
  color: var(--color-fg);
  font-size: var(--fs-4);
  line-height: var(--lh-snug);
}

@media (max-width: 800px) {
  .section-intro,
  .section-intro--reversed {
    grid-template-columns: 1fr;
  }
  .section-intro--reversed .section-figure { order: 0; }
}

/* --- Photography page --------------------------------------------------- */
main.photography { padding-top: 0; }

.hero-photography { min-height: clamp(480px, 78vh, 720px); }
.hero-photography .hero-content { padding-block: var(--sp-10) var(--sp-9); }
.hero-photography .hero-title { font-size: clamp(2.75rem, 7vw, 5rem); letter-spacing: -0.03em; }
.hero-photography .hero-tagline { max-width: 44rem; color: var(--color-fg-muted); }

main.exploration { padding-top: 0; }

.hero-exploration { min-height: clamp(480px, 78vh, 720px); }
.hero-exploration .hero-content { padding-block: var(--sp-10) var(--sp-9); }
.hero-exploration .hero-title { font-size: clamp(2.75rem, 7vw, 5rem); letter-spacing: -0.03em; }
.hero-exploration .hero-tagline { max-width: 44rem; color: var(--color-fg-muted); }

/* Awards & Press — non-interactive figure cards (no destination URL). */
.award-grid {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--sp-5);
}
.award-card {
  margin: 0;
  display: flex;
  flex-direction: column;
  height: 100%;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  overflow: hidden;
}
.award-thumb {
  aspect-ratio: 16 / 10;
  overflow: hidden;
  border-bottom: 1px solid var(--color-border);
}
.award-thumb img { width: 100%; height: 100%; object-fit: cover; }
.award-body {
  padding: var(--sp-5);
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
}
.award-honor {
  margin: 0;
  font-size: var(--fs-4);
  font-weight: 600;
  line-height: var(--lh-snug);
  letter-spacing: -0.005em;
}
.award-honor a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid var(--color-border-strong);
  transition: border-color var(--transition);
}
.award-honor a:hover,
.award-honor a:focus-visible { border-color: var(--color-fg); }
.award-desc {
  margin: 0;
  font-size: var(--fs-small);
  color: var(--color-fg-muted);
  line-height: var(--lh-body);
}
.award-meta {
  margin: 0;
  font-size: var(--fs-small);
  color: var(--color-fg-dim);
}
.award-meta a {
  color: var(--color-fg-muted);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color var(--transition);
}
.award-meta a:hover,
.award-meta a:focus-visible { color: var(--color-fg); }
.award-label {
  color: var(--color-fg-muted);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.78em;
  margin-right: var(--sp-2);
}

/* Specialized techniques — featured block sits close to its sample grid. */
.technique-block { margin-bottom: var(--sp-5); }
.sample-grid {
  list-style: none;
  padding: 0;
  margin: 0 0 var(--sp-8);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--sp-4);
}
.sample-grid:last-child { margin-bottom: 0; }
.sample-card {
  margin: 0;
  aspect-ratio: 3 / 2;
  overflow: hidden;
  border: 1px solid var(--color-border);
}
.sample-card img { width: 100%; height: 100%; object-fit: cover; }

/* --- Stub hero (Stage 1 only) ------------------------------------------ */
.stub-hero {
  min-height: calc(100vh - var(--nav-height));
  display: grid;
  place-items: center;
  text-align: center;
  padding: var(--sp-9) var(--container-pad);
}

.stub-hero .eyebrow {
  display: inline-block;
  font-size: var(--fs-small);
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--color-fg-dim);
  margin-bottom: var(--sp-5);
}

.stub-hero h1 { margin-bottom: var(--sp-5); }

.stub-hero p {
  max-width: 36rem;
  margin-inline: auto;
  font-size: var(--fs-4);
}

/* --- Footer ------------------------------------------------------------- */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: var(--sp-7) 0;
  margin-top: var(--sp-9);
}

.footer-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-5);
  flex-wrap: wrap;
}

.footer-copy {
  margin: 0;
  font-size: var(--fs-small);
  color: var(--color-fg-dim);
}

.footer-social {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  gap: var(--sp-5);
}

.footer-social a {
  color: var(--color-fg-muted);
  display: inline-flex;
  width: 36px;
  height: 36px;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: color var(--transition), background var(--transition);
}

.footer-social a:hover,
.footer-social a:focus-visible {
  color: var(--color-bg);
  background: var(--color-fg);
}

@media (max-width: 520px) {
  .footer-wrap { flex-direction: column; align-items: flex-start; }
}

/* --- Reduced motion ----------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
}

/* --- Exploration blog: directories & posts ----------------------------- */
main.post,
main.directory { padding-top: 0; }

.post-hero { min-height: clamp(480px, 78vh, 720px); }
.post-hero .hero-content { padding-block: var(--sp-10) var(--sp-9); }
.post-hero .hero-title { font-size: clamp(2.75rem, 7vw, 5rem); letter-spacing: -0.03em; }
.post-hero .eyebrow a { text-decoration: none; }
.post-date { color: var(--color-fg-muted); font-size: var(--fs-small); margin: var(--sp-3) 0 0; }

.directory-head .section-tagline { margin-bottom: 0; }

.post-grid {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--sp-6);
}
.post-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  text-decoration: none;
  color: var(--color-fg);
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  transition: border-color var(--transition);
}
.research-section--alt .post-card { background: var(--color-bg); }
.post-card:hover,
.post-card:focus-visible { border-color: var(--color-fg); }
.post-thumb { margin: 0; aspect-ratio: 16 / 10; overflow: hidden; }
.post-thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
.post-card-body { padding: var(--sp-5); display: flex; flex-direction: column; gap: var(--sp-2); }
.post-card-title { font-size: var(--fs-4); margin: 0; }
.post-card .post-date { margin: 0; }
.post-summary { color: var(--color-fg-muted); margin: 0; }

.post-empty { color: var(--color-fg-muted); }

.post-body {
  max-width: 42rem;
  margin: 0 auto;
}
.post-body h2 { font-size: var(--fs-3); margin: var(--sp-7) 0 var(--sp-4); }
.post-body h3 { font-size: var(--fs-4); margin: var(--sp-6) 0 var(--sp-3); }
.post-body p { margin: 0 0 var(--sp-5); }
.post-body ul,
.post-body ol { margin: 0 0 var(--sp-5) var(--sp-5); padding: 0; color: var(--color-fg-muted); }
.post-body li { margin: 0 0 var(--sp-2); }
.post-body a { color: var(--color-fg); }
.post-body img { max-width: 100%; height: auto; display: block; margin: var(--sp-6) auto; }
.post-body code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.9em;
  background: var(--color-bg-elevated);
  padding: 0.1em 0.35em;
  border-radius: 3px;
}
.post-body pre {
  background: var(--color-bg-elevated);
  padding: var(--sp-5);
  overflow-x: auto;
  margin: 0 0 var(--sp-5);
}
.post-body pre code { background: none; padding: 0; }
.post-body blockquote {
  margin: 0 0 var(--sp-5);
  padding-left: var(--sp-5);
  border-left: 2px solid var(--color-border);
  color: var(--color-fg-muted);
}
.post-back { margin-top: var(--sp-7); }

/* --- Tags & filter ------------------------------------------------------ */
.tag-filter {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
  margin-bottom: var(--sp-6);
}
.tag-chip {
  font-size: var(--fs-small);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-fg-muted);
  background: transparent;
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius);
  padding: var(--sp-1) var(--sp-3);
  cursor: pointer;
  transition: border-color var(--transition), color var(--transition),
              background var(--transition);
}
.tag-chip:hover,
.tag-chip:focus-visible { border-color: var(--color-fg); color: var(--color-fg); }
.tag-chip[aria-pressed="true"] {
  background: var(--color-fg);
  border-color: var(--color-fg);
  color: var(--color-bg);
}
.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
  margin: var(--sp-1) 0 0;
}
.tag {
  font-size: var(--fs-small);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-fg-dim);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 2px var(--sp-2);
}
.post-header-tags { margin-top: var(--sp-3); }