/* Leo Tsukada — personal website
   Single stylesheet shared by index.html, page1.html and page3.html. */

:root {
  --ink: #232323;
  --ink-soft: #4a4a4a;
  --muted: #7a7a7a;
  --paper: #fafafa;
  --white: #ffffff;
  --dark: #232323;
  --dark-2: #2e2e2e;
  --accent: #40b0bf;
  --line: #e6e6e6;

  /* Colors adjustable in the editor (Colors panel). The editor writes
     overrides into a <style id="theme"> block in each page's <head>. */
  --nav-bg: #ffffff;
  --nav-link: var(--ink);
  --nav-link-hover: var(--accent);
  --social-color: var(--ink);
  --social-hover: var(--accent);
  --hero-name: var(--paper);
  --hero-tagline: var(--paper);
  --hero-line: var(--hero-name);
  --hero-credit: var(--paper);
  --news-title: var(--paper);
  --about-title: var(--ink);
  --about-text: var(--ink);
  --contact-title: var(--paper);
  --footer-text: #bdbdbd;

  --font-display: "Oswald", "Arial Narrow", system-ui, sans-serif;
  --font-body: "Inter", system-ui, -apple-system, "Segoe UI", "Hiragino Sans", "Noto Sans JP", sans-serif;

  --nav-h: 72px;
  --radius: 10px;
  --max-w: 1180px;
  --gutter: clamp(16px, 4vw, 32px);
  --shadow: 0 1px 2px rgb(0 0 0 / .06), 0 8px 24px rgb(0 0 0 / .08);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 8px);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }

a { color: inherit; }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.15;
  margin: 0;
  letter-spacing: .01em;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.container {
  width: 100%;
  max-width: var(--max-w);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.skip-link {
  position: absolute;
  left: 8px;
  top: -100px;
  z-index: 2000;
  padding: .5rem 1rem;
  background: var(--ink);
  color: var(--white);
  border-radius: 6px;
}
.skip-link:focus { top: 8px; }

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

.sprite { position: absolute; width: 0; height: 0; overflow: hidden; }

.icon { width: 1.25em; height: 1.25em; fill: currentColor; flex: none; }

.section-title {
  font-size: clamp(2rem, 4.5vw, 3rem);
  margin-bottom: 2.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: .4em;
  padding: .6rem 1.2rem;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 500;
  letter-spacing: .03em;
  text-decoration: none;
  color: var(--white);
  background: var(--ink);
  border: 2px solid var(--ink);
  border-radius: 999px;
  transition: background-color .2s, color .2s, transform .2s;
}
.btn:hover { background: transparent; color: var(--ink); }
.btn--light { background: var(--white); color: var(--ink); border-color: var(--white); }
.btn--light:hover { background: transparent; color: var(--white); }

/* ---------- Navigation ---------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 1000;
  background: color-mix(in srgb, var(--nav-bg) 82%, transparent);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color .3s, box-shadow .3s;
}
.site-header.is-scrolled {
  border-bottom-color: var(--line);
  box-shadow: 0 2px 12px rgb(0 0 0 / .05);
}

.nav {
  display: flex;
  align-items: center;
  gap: 1rem;
  height: var(--nav-h);
}

.nav__brand img { height: 3rem; width: auto; }

.nav__toggle {
  display: none;
  margin-left: auto;
  width: 44px; height: 44px;
  padding: 10px;
  background: none;
  border: 0;
  cursor: pointer;
}
.nav__toggle span {
  display: block;
  height: 2px;
  margin: 5px 0;
  background: var(--nav-link);
  border-radius: 2px;
  transition: transform .25s, opacity .25s;
}
.nav__toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav__toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav__toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav__menu {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-left: auto;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: .25rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav__link {
  display: inline-flex;
  align-items: center;
  gap: .3em;
  padding: .5rem .75rem;
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--nav-link);
  text-decoration: none;
  background: none;
  border: 0;
  border-radius: 6px;
  cursor: pointer;
  transition: color .2s;
}
.nav__link:hover,
.nav__link[aria-current="page"] { color: var(--nav-link-hover); }

.nav__dropdown { position: relative; }
.nav__dropdown .chevron { width: .8em; height: .8em; transition: transform .2s; }
.nav__dropdown [aria-expanded="true"] .chevron { transform: rotate(180deg); }

.nav__submenu {
  position: absolute;
  top: calc(100% + .5rem);
  right: 0;
  min-width: 12rem;
  margin: 0;
  padding: .5rem;
  list-style: none;
  background: var(--nav-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.nav__submenu a {
  display: flex;
  align-items: center;
  gap: .5em;
  padding: .5rem .75rem;
  font-family: var(--font-display);
  color: var(--nav-link);
  text-decoration: none;
  border-radius: 6px;
}
.nav__submenu a:hover { background: color-mix(in srgb, var(--nav-link) 6%, transparent); color: var(--nav-link-hover); }

.nav__social {
  display: flex;
  gap: .25rem;
}
.nav__social a {
  display: grid;
  place-items: center;
  width: 36px; height: 36px;
  color: var(--icon-color, var(--social-color));
  border-radius: 50%;
  transition: color .2s, background-color .2s;
}
.nav__social a:hover { color: var(--social-hover); background: color-mix(in srgb, var(--nav-link) 6%, transparent); }
.nav__social .icon { width: 18px; height: 18px; }

@media (max-width: 991px) {
  .nav__toggle { display: block; }

  .nav__menu {
    position: absolute;
    top: var(--nav-h);
    left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 1rem;
    padding: 1rem var(--gutter) 1.5rem;
    background: var(--nav-bg);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 12px 24px rgb(0 0 0 / .08);
    max-height: calc(100dvh - var(--nav-h));
    overflow-y: auto;
  }
  .nav__menu:not(.is-open) { display: none; }

  .nav__links { flex-direction: column; align-items: stretch; }
  .nav__link { width: 100%; justify-content: center; font-size: 1.2rem; }

  .nav__submenu {
    position: static;
    border: 0;
    box-shadow: none;
    background: color-mix(in srgb, var(--nav-link) 4%, var(--nav-bg));
    text-align: center;
  }
  .nav__submenu a { justify-content: center; }

  .nav__social { justify-content: center; }
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: min(92vh, 900px);
  padding-top: var(--nav-h);
  color: var(--paper);
  /* background-image is set inline from the editor's hero image */
  background-color: #0b0b1a;
  background-position: center;
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed; /* image stays put while the page scrolls over it */
}

.hero__title {
  font-size: clamp(3rem, 9vw, 4.6rem);
  font-weight: 700;
  color: var(--hero-name);
}
.hero__title::after {
  content: "";
  display: block;
  width: min(530px, 80%);
  height: 4px;
  margin-top: 1rem;
  background: var(--hero-line);
  border-radius: 2px;
  opacity: .9;
}

.hero__tagline {
  margin: 1.5rem 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 3.5vw, 2.2rem);
  font-weight: 300;
  color: var(--hero-tagline);
}

.hero__credit {
  position: absolute;
  right: var(--gutter);
  bottom: .75rem;
  margin: 0;
  font-size: .75rem;
  color: var(--hero-credit);
  opacity: .7;
}

@media (max-width: 991px) {
  .hero { text-align: center; }
  .hero__title::after { margin-inline: auto; }
}

/* Custom text positions set in the editor (hero--free). Phones keep the
   automatic centered layout so nothing runs off a small screen. */
@media (min-width: 768px) {
  .hero--free .hero__obj {
    position: absolute;
    left: var(--x, 10%);
    top: var(--y, 50%);
    right: auto;
    bottom: auto;
    width: max-content;
    max-width: 92%;
    margin: 0;
    text-align: left;
    transform: translate(0, -50%);
  }
  .hero--free .hero__obj[data-align="center"] { text-align: center; transform: translate(-50%, -50%); }
  .hero--free .hero__obj[data-align="right"] { text-align: right; transform: translate(-100%, -50%); }

  .hero--free .hero__title { min-width: min(530px, 60vw); }
  .hero--free .hero__title::after { width: 100%; margin-inline: 0; }
}

/* ---------- News carousel ---------- */
.news {
  padding-block: 6rem 4rem;
  color: var(--paper);
  background: var(--dark);
}
.news .section-title { text-align: center; color: var(--news-title); }

.carousel { position: relative; }

.carousel__track {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: calc((100% - 2 * 1.5rem) / 3);
  gap: 1.5rem;
  margin: 0;
  padding: .5rem 0 1.5rem;
  list-style: none;
  overflow-x: auto;
  overscroll-behavior-x: contain;
  scroll-snap-type: x mandatory;
  scrollbar-width: thin;
  scrollbar-color: #555 transparent;
}
@media (max-width: 991px) {
  .carousel__track { grid-auto-columns: calc((100% - 1.5rem) / 2); }
}
@media (max-width: 640px) {
  .carousel__track { grid-auto-columns: 85%; }
}

.news-card {
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  color: var(--ink);
  background: var(--paper);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.news-card__img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  background: var(--white);
  border-bottom: 1px solid var(--line);
}

.news-card__body {
  display: flex;
  flex: 1;
  flex-direction: column;
  padding: 1.25rem 1.25rem 1.5rem;
}

.news-card__title { font-size: 1.5rem; }

.news-card__date {
  margin-top: .25rem;
  font-size: .9rem;
  font-variant-numeric: tabular-nums;
  color: var(--muted);
}

.news-card__text {
  flex: 1;
  margin: .75rem 0 1.25rem;
  font-size: .95rem;
  color: var(--ink-soft);
}

.news-card .btn { align-self: flex-start; }

.carousel__controls {
  display: flex;
  justify-content: center;
  gap: .75rem;
  margin-top: .5rem;
}

.carousel__btn {
  display: grid;
  place-items: center;
  width: 48px; height: 48px;
  color: var(--white);
  background: transparent;
  border: 2px solid rgb(255 255 255 / .6);
  border-radius: 50%;
  cursor: pointer;
  transition: background-color .2s, border-color .2s, opacity .2s;
}
.carousel__btn:hover { background: var(--white); border-color: var(--white); color: var(--ink); }
.carousel__btn:disabled { opacity: .3; pointer-events: none; }
.carousel__btn .icon { width: 24px; height: 24px; }

/* ---------- About ---------- */
.about {
  padding-block: 6rem;
  background: var(--paper);
}

.about__grid {
  display: grid;
  grid-template-columns: 1fr minmax(260px, 360px);
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
}
@media (max-width: 991px) {
  .about__grid { grid-template-columns: 1fr; }
  .about__photo { max-width: 360px; margin-inline: auto; }
}

.about__text .section-title { color: var(--about-title); }
.about__text p { margin: 0 0 1.25rem; font-size: 1.05rem; color: var(--about-text); }
.about__text a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
.about__text a:hover { color: var(--about-text); }

.about__photo img {
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ---------- Contact ---------- */
.contact {
  padding-block: 4rem 3rem;
  color: var(--paper);
  background: var(--dark);
}
.contact .section-title { text-align: center; margin-bottom: 2rem; color: var(--contact-title); }

.contact__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
  max-width: 900px;
  margin-inline: auto;
}

.contact-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .5rem;
  padding: 2rem 1.5rem;
  text-align: center;
  background: var(--dark-2);
  border: 1px solid rgb(255 255 255 / .08);
  border-radius: var(--radius);
}
.contact-card .icon { width: 28px; height: 28px; color: var(--accent); }
.contact-card h3 { font-size: 1.25rem; }
.contact-card p, .contact-card address { margin: 0; font-style: normal; color: #d6d6d6; }
.contact-card a { color: var(--paper); text-underline-offset: 3px; }
.contact-card a:hover { color: var(--accent); }

/* ---------- Coming soon (sub pages) ---------- */
.coming-soon {
  display: grid;
  place-items: center;
  min-height: 100vh;
  min-height: 100dvh;
  padding: calc(var(--nav-h) + 2rem) var(--gutter) 4rem;
  text-align: center;
  color: var(--white);
  background: linear-gradient(135deg, #000 10%, #bbb 100%);
}
.coming-soon h1 { font-size: clamp(3rem, 10vw, 4.6rem); font-weight: 700; }
.coming-soon p { margin: 1rem 0 2rem; font-size: 1.1rem; opacity: .85; }

/* ---------- Research page ---------- */
.page-hero {
  padding: calc(var(--nav-h) + clamp(3rem, 8vw, 5rem)) 0 clamp(2.5rem, 6vw, 4rem);
  color: var(--paper);
  background: linear-gradient(135deg, #000 10%, #3a3a3a 100%);
  background-attachment: fixed;
}
/* Optional header image, set inline from the editor ("Header background image") */
.page-hero--image,
.coming-soon--image {
  background-color: #0b0b1a;
  background-position: center;
  background-size: cover;
  background-repeat: no-repeat;
  background-attachment: fixed;
}
/* The research header is only a short band, so a viewport-sized "cover" image
   shows just a slice of it. Fit the image to the window width instead (never
   narrower than 1140px, so it still fills the 640px band) and anchor it at the top. */
.page-hero--image {
  display: flex;
  flex-direction: column;
  justify-content: flex-end; /* keep the text near the bottom of the taller band */
  min-height: min(65vh, 640px);
  background-size: max(100vw, 1140px) auto;
  background-position: center top;
}
/* iOS/Android browsers ignore or mis-scale fixed backgrounds: scroll normally there */
@media (hover: none) {
  .hero, .page-hero, .page-hero--image, .coming-soon--image { background-attachment: scroll; }
  .page-hero--image { background-size: cover; background-position: center; }
}
.page-hero__title { font-size: clamp(2.75rem, 8vw, 4.2rem); font-weight: 700; }
.page-hero__intro { max-width: 760px; margin-top: 1.25rem; }
.page-hero__intro p { margin: 0 0 1rem; font-size: 1.1rem; color: #e2e2e2; }

.research-toc {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin: 1.75rem 0 0;
  padding: 0;
  list-style: none;
}
.research-toc a {
  display: inline-block;
  padding: .35rem .9rem;
  font-size: .9rem;
  font-weight: 500;
  color: var(--ink);
  background: var(--paper);
  text-decoration: none;
  border: 1px solid var(--paper);
  border-radius: 999px;
  transition: background-color .2s, border-color .2s, color .2s;
}
/* Light pills by default; flip back to outlined white text on hover/focus */
.research-toc a:hover,
.research-toc a:focus-visible { color: var(--paper); background: rgb(0 0 0 / .35); border-color: var(--paper); }

.research-item { padding-block: clamp(3rem, 7vw, 5rem); background: var(--paper); }
.research-item:nth-of-type(odd) { background: var(--white); }

.research-item__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
}
.research-item:nth-of-type(odd) .research-item__figure { order: -1; }
.research-item--text .research-item__grid { grid-template-columns: minmax(0, 1fr); max-width: 820px; }

.research-item__meta {
  margin: 0 0 .5rem;
  font-size: .85rem;
  font-weight: 600;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--accent);
}
.research-item__text h2 { font-size: clamp(1.75rem, 3.5vw, 2.4rem); margin-bottom: 1.25rem; }
.research-item__body p { margin: 0 0 1rem; font-size: 1.02rem; color: var(--ink-soft); }
.research-item__body a { color: var(--accent); text-underline-offset: 3px; }

.research-item__papers { margin-top: 1.5rem; padding-top: 1.25rem; border-top: 1px solid var(--line); }
.research-item__papers h3 {
  margin-bottom: .6rem;
  font-size: .95rem;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--muted);
}
.research-item__papers ul { margin: 0; padding: 0; list-style: none; }
.research-item__papers li { position: relative; margin: 0 0 .5rem; padding-left: 1.1rem; font-size: .95rem; }
.research-item__papers li::before {
  content: "";
  position: absolute;
  left: 0; top: .6em;
  width: 6px; height: 6px;
  background: var(--accent);
  border-radius: 50%;
}
.research-item__papers a { color: var(--ink); text-decoration-color: rgb(64 176 191 / .5); text-underline-offset: 3px; }
.research-item__papers a:hover { color: var(--accent); }

.research-item__figure { margin: 0; }
.research-item__figure > a {
  display: block;
  padding: clamp(.75rem, 2vw, 1.25rem);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: transform .2s;
}
.research-item__figure > a:hover { transform: translateY(-2px); }
.research-item__figure img { width: 100%; height: auto; max-height: 520px; object-fit: contain; }
.research-item__figure figcaption { margin-top: .85rem; font-size: .88rem; line-height: 1.55; color: var(--muted); }
.research-item__source { display: block; margin-top: .25rem; }
.research-item__source a { color: var(--accent); text-underline-offset: 3px; }

@media (max-width: 991px) {
  .research-item__grid { grid-template-columns: minmax(0, 1fr); }
  .research-item:nth-of-type(odd) .research-item__figure { order: 0; }
}

/* ---------- Footer ---------- */
.site-footer {
  padding-block: 1.75rem;
  font-size: .9rem;
  text-align: center;
  color: var(--footer-text);
  background: var(--dark);
  border-top: 1px solid rgb(255 255 255 / .08);
}
.site-footer p { margin: 0; }

/* ---------- Back to top ---------- */
.to-top {
  position: fixed;
  right: 1.25rem;
  bottom: 1.25rem;
  z-index: 900;
  display: grid;
  place-items: center;
  width: 44px; height: 44px;
  color: var(--white);
  background: rgb(35 35 35 / .85);
  border: 1px solid rgb(255 255 255 / .2);
  border-radius: 50%;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity .25s, transform .25s, visibility .25s;
}
.to-top.is-visible { opacity: 1; visibility: visible; transform: none; }
.to-top:hover { background: var(--accent); }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}