/* ==========================================================================
   al-folio–style stylesheet for zikaixiong.github.io
   Clean, minimal, publication-centered academic design.
   ========================================================================== */

:root {
  --theme-color: #1F4E79;      /* site accent: deep navy */
  --theme-dark: #163A5C;       /* accent hover */
  --text-color: #212529;
  --muted-color: #6c757d;
  --light-muted: #919ba4;
  --border-color: #e9ecef;
  --bg-color: #FAF9F5;   /* very light warm cream (Claude-like) */
  --max-width: 950px;
  --sans: "Inter", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg-color);
  color: var(--text-color);
  font-family: var(--sans);
  font-size: 1rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.25rem;
}

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

b, strong { font-weight: 600; }
em { font-style: italic; }

hr {
  border: 0;
  border-top: 1px solid var(--border-color);
  margin: 2.5rem 0;
}

/* --------------------------------------------------------------------------
   Top navigation
   -------------------------------------------------------------------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(250, 249, 245, 0.96);
  backdrop-filter: saturate(180%) blur(8px);
  -webkit-backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--border-color);
}

.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  min-height: 3.4rem;
  padding-top: 0.35rem;
  padding-bottom: 0.35rem;
}

.navbar-brand {
  font-family: var(--serif);
  font-size: 1.18rem;
  font-weight: 600;
  color: var(--theme-color);
  letter-spacing: 0.01em;
}
.navbar-brand:hover { color: var(--theme-color); text-decoration: none; }

.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.45rem;
  line-height: 1;
  color: var(--text-color);
  cursor: pointer;
  padding: 0.25rem 0.5rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.15rem;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a { color: #495057; font-size: 0.95rem; }
.nav-links a:hover { color: var(--theme-color); text-decoration: none; }
.nav-links a.active { color: var(--text-color); font-weight: 600; }

@media (max-width: 900px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none;
    flex-direction: column;
    align-items: flex-start;
    width: 100%;
    gap: 0.35rem;
    padding: 0.25rem 0 0.9rem;
  }
  .nav-links.open { display: flex; }
}

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

main.container {
  padding-top: 2.25rem;
  padding-bottom: 3rem;
}

.page-title {
  font-family: var(--serif);
  font-size: 2.1rem;
  font-weight: 600;
  line-height: 1.2;
  margin: 0 0 0.4rem;
  color: var(--theme-color);
}

.page-desc {
  color: var(--muted-color);
  margin: 0 0 2rem;
}

h2.section-title {
  font-family: var(--serif);
  font-size: 1.4rem;
  font-weight: 600;
  margin: 2.4rem 0 1.1rem;
  padding-bottom: 0.3rem;
  border-bottom: 1px solid var(--border-color);
  color: var(--theme-color);
}

h3.subsection-title {
  font-family: var(--serif);
  font-size: 1.12rem;
  font-weight: 600;
  margin: 1.8rem 0 0.8rem;
  color: var(--theme-color);
}

.section-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
}
.section-head .view-all {
  font-size: 0.85rem;
  white-space: nowrap;
}

.site-footer {
  border-top: 1px solid var(--border-color);
  margin-top: 2rem;
  padding: 1.4rem 0 2.2rem;
  color: var(--light-muted);
  font-size: 0.85rem;
}

/* --------------------------------------------------------------------------
   Home / profile
   -------------------------------------------------------------------------- */

.profile-row {
  display: flex;
  flex-direction: row-reverse;   /* photo (first in DOM) sits on the right */
  gap: 2.2rem;
  align-items: flex-start;
  margin-top: 1.6rem;
}

.profile-main { flex: 1 1 auto; min-width: 0; }
.profile-main p { margin: 0 0 1rem; }

.profile-side {
  flex: 0 0 215px;
  text-align: center;
}
.profile-side img {
  width: 100%;
  height: auto;
  border-radius: 0.5rem;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.12);
}
.profile-address {
  margin-top: 0.8rem;
  font-size: 0.875rem;
  color: var(--muted-color);
  line-height: 1.55;
}

@media (max-width: 700px) {
  .profile-row { flex-direction: column; align-items: center; }
  .profile-side { flex-basis: auto; max-width: 240px; }
  .profile-main { width: 100%; }
}

.profile-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 0.9rem;
  margin: 1.3rem 0 0.4rem;
}
.profile-links a {
  display: inline-block;
  font-size: 0.84rem;
  font-weight: 500;
  border: 1px solid var(--border-color);
  border-radius: 0.3rem;
  padding: 0.25rem 0.7rem;
  color: var(--text-color);
}
.profile-links a:hover {
  border-color: var(--theme-color);
  color: var(--theme-color);
  text-decoration: none;
}

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

.news-table { width: 100%; border-collapse: collapse; }
.news-table td {
  vertical-align: top;
  padding-top: 0.55rem;
  padding-bottom: 0.55rem;
}
.news-table tr + tr td { border-top: 1px solid var(--border-color); }

.news-date {
  white-space: nowrap;
  color: var(--muted-color);
  font-weight: 500;
  font-size: 0.9rem;
  padding-right: 1.4rem;
  width: 1%;
}

.news-sub {
  display: block;
  font-size: 0.92rem;
  color: var(--muted-color);
}

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

.pub-note {
  color: var(--muted-color);
  font-size: 0.9rem;
  margin: 0 0 1.4rem;
}

.author-star { font-weight: 700; }

ul.pub-list { list-style: none; margin: 0 0 0.5rem; padding: 0; }
.pub-list > li { margin-bottom: 1.7rem; }

.pub-title {
  display: block;
  font-size: 1.05rem;
  font-weight: 600;
  line-height: 1.4;
}

.pub-authors { display: block; margin-top: 0.1rem; }

.pub-venue {
  display: block;
  color: #333740;
  margin-top: 0.1rem;
}

.pub-links {
  margin-top: 0.4rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

a.pub-badge {
  display: inline-block;
  font-size: 0.74rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--theme-color);
  border: 1px solid var(--theme-color);
  border-radius: 0.25rem;
  padding: 0.12rem 0.5rem;
  line-height: 1.5;
}
a.pub-badge:hover {
  background: var(--theme-color);
  color: #fff;
  text-decoration: none;
}

.pub-award {
  display: block;
  margin-top: 0.3rem;
  font-size: 0.95rem;
  color: var(--theme-dark);
  font-weight: 500;
}
.pub-award a { color: inherit; }
.pub-award a:hover { color: inherit; text-decoration: underline; }

/* --------------------------------------------------------------------------
   Generic entries (experience, teaching, talks)
   -------------------------------------------------------------------------- */

ul.entry-list { list-style: none; margin: 0; padding: 0; }
.entry-list > li { margin-bottom: 1.7rem; }

.entry-title {
  display: block;
  font-size: 1.05rem;
  font-weight: 600;
  line-height: 1.45;
}

.entry-meta { color: var(--muted-color); }

ul.detail-list {
  list-style: disc;
  margin: 0.35rem 0 0;
  padding-left: 1.25rem;
}
.detail-list > li { margin-bottom: 0.15rem; }

ul.plain-list {
  list-style: disc;
  margin: 0;
  padding-left: 1.25rem;
}
.plain-list > li { margin-bottom: 0.55rem; }

.highlight { color: var(--theme-dark); font-weight: 500; }

/* --------------------------------------------------------------------------
   Photo gallery
   -------------------------------------------------------------------------- */

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
  gap: 1.1rem;
  margin-top: 1rem;
}
.gallery-grid figure { margin: 0; }
.gallery-grid img {
  display: block;
  width: 100%;
  height: 230px;
  object-fit: cover;
  border-radius: 0.4rem;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.12);
}
.gallery-grid figcaption {
  font-size: 0.82rem;
  color: var(--muted-color);
  margin-top: 0.35rem;
  line-height: 1.45;
}

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