/* ==========================================================================
   Jeremy Zhengqi Huang — personal site
   Plain HTML/CSS/JS. Edit js/data.js to add news or publications.
   ========================================================================== */

/* --- Design tokens -------------------------------------------------------- */

:root {
  --bg: #fcfcfb;
  --bg-subtle: #ebe8e5;
  --text: #292322;
  --text-muted: #6a6360;
  --text-faint: #887e7b;
  --border: #e2dcd8;
  --accent: #a44b3a;
  --accent-soft: rgba(164, 75, 58, 0.09);
  --nav-bg: rgba(252, 252, 251, 0.72);
  --shadow: 0 1px 2px rgba(58, 45, 41, 0.06), 0 10px 28px rgba(58, 45, 41, 0.08);

  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica,
    Arial, sans-serif;
  /* Castoro ships Regular + Italic only — never ask it for a bold weight. */
  --font-head: "Castoro", Georgia, "Times New Roman", serif;
  --measure: 860px;
  --nav-h: 60px;
}

:root[data-theme="dark"] {
  --bg: #1c1917;
  --bg-subtle: #26211f;
  --text: #ebe7e5;
  --text-muted: #a49a96;
  --text-faint: #8c807b;
  --border: #37302d;
  --accent: #dd6957;
  --accent-soft: rgba(221, 105, 87, 0.14);
  --nav-bg: rgba(28, 25, 23, 0.72);
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.35), 0 10px 28px rgba(0, 0, 0, 0.3);
}

/* --- Base ----------------------------------------------------------------- */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 16px);
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 1rem;
  line-height: 1.65;
  letter-spacing: -0.011em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: "cv05" 1, "ss01" 1;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
  text-underline-offset: 2px;
}

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

::selection {
  background: var(--accent-soft);
}

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

.container {
  width: 100%;
  max-width: var(--measure);
  margin: 0 auto;
  padding: 0 24px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--bg);
  color: var(--text);
  padding: 10px 16px;
  z-index: 200;
}

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

/* --- Navbar (gaussian blur) ----------------------------------------------- */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--nav-h);
  background: var(--nav-bg);
  -webkit-backdrop-filter: saturate(180%) blur(18px);
  backdrop-filter: saturate(180%) blur(18px);
  border-bottom: 1px solid var(--border);
}

/* Fallback for browsers without backdrop-filter: use an opaque bar instead. */
@supports not ((-webkit-backdrop-filter: blur(1px)) or (backdrop-filter: blur(1px))) {
  .nav {
    background: var(--bg);
  }
}

.nav__inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.nav__brand {
  color: var(--text-muted);
  font-family: var(--font-head);
  font-size: 1.0625rem;
  font-weight: 400;
  white-space: nowrap;
}

.nav__brand:hover {
  text-decoration: none;
  color: var(--accent);
}

.nav__brand strong {
  color: var(--text);
  font-weight: 400;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav__link {
  color: var(--text-muted);
  font-family: var(--font-head);
  font-size: 0.9375rem;
  font-weight: 400;
  padding: 6px 10px;
  border-radius: 8px;
  transition: color 0.15s ease, background 0.15s ease;
}

.nav__link:hover {
  color: var(--text);
  background: var(--bg-subtle);
  text-decoration: none;
}

.nav__link.is-active {
  color: var(--accent);
}

.theme-toggle {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  margin-left: 4px;
  padding: 0;
  border: 0;
  border-radius: 8px;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: color 0.15s ease, background 0.15s ease;
}

.theme-toggle:hover {
  color: var(--text);
  background: var(--bg-subtle);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
  /* SVG's default fill is black, not currentColor — set it or the icon
     stays black and vanishes against the dark background. */
  fill: currentColor;
}

:root[data-theme="dark"] .theme-toggle .icon-moon,
:root:not([data-theme="dark"]) .theme-toggle .icon-sun {
  display: none;
}

/* --- Page scaffolding ----------------------------------------------------- */

.page {
  padding-top: calc(var(--nav-h) + 56px);
  padding-bottom: 72px;
}

.section {
  margin-top: 64px;
}

.section__title {
  margin: 0 0 20px;
  font-family: var(--font-head);
  font-size: 1.875rem;
  font-weight: 400;
  letter-spacing: -0.005em;
  color: var(--text);
}

/* --- Hero ----------------------------------------------------------------- */

.hero__name {
  margin: 0;
  color: var(--text-muted);
  font-family: var(--font-head);
  font-size: clamp(2rem, 6vw, 2.75rem);
  font-weight: 400;
  letter-spacing: -0.01em;
  line-height: 1.15;
}

.hero__name strong {
  color: var(--text);
  font-weight: 400;
}

.hero__subtitle {
  margin: 10px 0 0;
  color: var(--text-muted);
  font-size: 1.0625rem;
}

.hero__body {
  display: grid;
  grid-template-columns: 1fr 240px;
  gap: 40px;
  align-items: start;
  margin-top: 28px;
}

.hero__bio p {
  margin: 0 0 16px;
}

.hero__bio p:last-child {
  margin-bottom: 0;
}

.hero__portrait {
  margin: 0;
}

.hero__portrait img {
  width: 100%;
  border-radius: 10px;
  box-shadow: var(--shadow);
}

/* --- Social icons --------------------------------------------------------- */

.socials {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  margin-top: 26px;
}

.socials a {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 8px;
  color: var(--text-muted);
  transition: color 0.15s ease, background 0.15s ease, transform 0.15s ease;
}

.socials a:hover {
  color: var(--accent);
  background: var(--bg-subtle);
  transform: translateY(-1px);
  text-decoration: none;
}

.socials svg {
  width: 19px;
  height: 19px;
  fill: currentColor;
}

.socials svg.stroke-icon {
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* --- News ----------------------------------------------------------------- */

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

.news__item {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 24px;
  padding: 16px 0;
  border-bottom: 1px solid var(--border);
}

.news__date {
  color: var(--text);
  font-size: 0.875rem;
  font-weight: 600;
  padding-top: 2px;
}

.news__text {
  color: var(--text-muted);
}

/* --- Publications --------------------------------------------------------- */

.pub-year {
  position: relative;
  margin: 48px 0 8px;
  padding-top: 8px;
  border-top: 1px solid var(--border);
  color: var(--text-faint);
  font-family: var(--font-head);
  font-size: 1.5rem;
  font-weight: 400;
  text-align: right;
  letter-spacing: 0;
}

.pub-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.pub {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 26px;
  padding: 22px 0;
  border-bottom: 1px solid var(--border);
}

.pub:last-child {
  border-bottom: 0;
}

.pub__preview img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-subtle);
}

.pub__title {
  margin: 0 0 5px;
  font-family: var(--font-head);
  font-size: 1.125rem;
  font-weight: 400;
  line-height: 1.35;
  letter-spacing: 0;
}

.pub__authors {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.9375rem;
}

.pub__authors .me {
  color: var(--text);
  font-weight: 600;
}

.pub__venue {
  margin: 2px 0 0;
  color: var(--text-muted);
  font-size: 0.9375rem;
  font-style: italic;
}

.pub__links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.chip {
  display: inline-block;
  padding: 3px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: transparent;
  color: var(--text-muted);
  font-family: inherit;
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}

.chip:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-soft);
  text-decoration: none;
}

.pub__abstract {
  margin-top: 12px;
  padding: 14px 16px;
  border-radius: 8px;
  background: var(--bg-subtle);
  color: var(--text-muted);
  font-size: 0.9375rem;
  line-height: 1.6;
}

.pub__abstract[hidden] {
  display: none;
}

/* --- Filter --------------------------------------------------------------- */

.filter {
  width: 100%;
  max-width: 340px;
  margin-top: 8px;
  padding: 9px 14px;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: var(--bg);
  color: var(--text);
  font-family: inherit;
  font-size: 0.9375rem;
}

.filter::placeholder {
  color: var(--text-faint);
}

.filter:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.page__lede {
  margin: 8px 0 0;
  color: var(--text-muted);
}

.empty {
  padding: 40px 0;
  color: var(--text-muted);
}

/* --- Footer --------------------------------------------------------------- */

.footer {
  margin-top: 72px;
  padding: 24px 0;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.875rem;
  text-align: center;
}

/* --- Responsive ----------------------------------------------------------- */

@media (max-width: 720px) {
  .hero__body {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .hero__portrait {
    max-width: 200px;
  }

  .news__item,
  .pub {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .pub__preview {
    max-width: 320px;
  }

  .nav__link {
    padding: 6px 6px;
    font-size: 0.875rem;
  }

  .nav__brand {
    font-size: 0.9375rem;
  }

  .nav__mid {
    display: none;
  }

  .nav__links {
    gap: 0;
  }
}

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

  * {
    transition: none !important;
  }
}