/* Huan Ning website. A concise academic profile: one family (IBM Plex Sans), five sizes,
   one sea-blue accent, hairline rules, and a sticky profile column on the home page. */

:root {
  --paper: #ffffff;
  --mist: #f4f6f8;
  --canvas: #eff2f5;
  --ink: #1b2026;
  --text: #2b323a;
  --slate: #5a636e;
  --rule: #e3e6ea;
  --sea: #1d5b82;
  --sea-deep: #134461;
  --on-sea: #ffffff;
  --font: "IBM Plex Sans", -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  --mono: "IBM Plex Mono", SFMono-Regular, Consolas, monospace;
  --fs-sm: .875rem;
  --fs-base: 1rem;
  --fs-body: 1.0625rem;
  --fs-md: 1.25rem;
  --fs-lg: 1.875rem;
  --container: 1080px;
  --narrow: 856px;
  color-scheme: light;
}
:root[data-theme="dark"] {
  --paper: #14171b;
  --mist: #1b1f24;
  --canvas: #0e1013;
  --ink: #eef1f4;
  --text: #d6dbe1;
  --slate: #9aa3ad;
  --rule: #2a3038;
  --sea: #86bde0;
  --sea-deep: #b5d7ee;
  --on-sea: #0f2433;
  color-scheme: dark;
}

/* Base */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--canvas); color: var(--text); font: 400 var(--fs-base)/1.6 var(--font); overflow-wrap: break-word; }
h1, h2, h3, h4 { margin: 0; color: var(--ink); font-weight: 600; line-height: 1.3; }
p { margin: 0; }
a { color: var(--sea); text-decoration: none; }
a:hover { color: var(--sea-deep); text-decoration: underline; text-underline-offset: 3px; }
a:focus-visible, button:focus-visible, summary:focus-visible { outline: 2px solid var(--sea); outline-offset: 2px; border-radius: 2px; }
img { max-width: 100%; height: auto; }
.icon { width: 1em; height: 1em; flex: none; vertical-align: -.125em; }
.container { width: min(var(--container), 100% - 40px); margin-inline: auto; }
.container.narrow { width: min(var(--narrow), 100% - 40px); }
.skip-link { position: absolute; left: 16px; top: -60px; z-index: 100; padding: 8px 16px; background: var(--paper); color: var(--sea); }
.skip-link:focus { top: 8px; }

/* Header */
.site-header { position: sticky; top: 0; z-index: 50; background: var(--paper); border-bottom: 1px solid var(--rule); }
.header-inner { display: flex; align-items: center; gap: 28px; min-height: 60px; }
.brand { color: var(--ink); font-size: var(--fs-md); font-weight: 600; letter-spacing: -.01em; white-space: nowrap; }
.brand:hover { color: var(--ink); text-decoration: none; }
.site-nav { display: flex; gap: 24px; margin-left: auto; }
.site-nav a { padding: 18px 0 16px; border-bottom: 2px solid transparent; color: var(--slate); font-weight: 500; }
.site-nav a:hover { color: var(--ink); text-decoration: none; }
.site-nav a[aria-current] { color: var(--ink); border-bottom-color: var(--sea); }
.header-tools { display: flex; align-items: center; gap: 2px; }
.icon-button { display: grid; place-items: center; width: 36px; height: 36px; border: 0; border-radius: 6px; background: none; color: var(--slate); font-size: 1.0625rem; cursor: pointer; }
.icon-button:hover { color: var(--ink); background: var(--mist); }
.theme-toggle .when-dark, :root[data-theme="dark"] .theme-toggle .when-light { display: none; }
:root[data-theme="dark"] .theme-toggle .when-dark { display: inline; }
.mobile-nav { display: none; position: relative; }
.mobile-nav summary { list-style: none; }
.mobile-nav summary::-webkit-details-marker { display: none; }
.mobile-nav nav { position: absolute; right: 0; top: 44px; display: flex; flex-direction: column; min-width: 200px; padding: 6px 0; background: var(--paper); border: 1px solid var(--rule); border-radius: 6px; box-shadow: 0 8px 24px rgba(20, 30, 40, .12); }
.mobile-nav nav a { padding: 8px 18px; color: var(--text); }
.mobile-nav nav a[aria-current] { color: var(--sea); font-weight: 600; }

/* Home: profile column plus content column */
.home { display: grid; grid-template-columns: 264px minmax(0, 1fr); gap: 48px; padding: 56px 0 88px; }
.profile { position: sticky; top: 108px; align-self: start; }
.profile-photo { display: block; width: 154px; height: 154px; border-radius: 50%; object-fit: cover; box-shadow: 0 0 0 1px var(--rule), 0 0 0 5px var(--paper), 0 0 0 6px var(--sea); }
.profile-id { margin: 24px 0 20px; }
.profile-name { color: var(--ink); font-size: var(--fs-lg); font-weight: 600; line-height: 1.15; letter-spacing: -.015em; }
.profile-role { margin-top: 8px; color: var(--slate); line-height: 1.5; }
.profile-links { display: grid; gap: 8px; margin: 0; padding: 20px 0 0; border-top: 1px solid var(--rule); list-style: none; font-size: var(--fs-sm); }
.profile-links a { display: inline-flex; align-items: center; gap: 10px; color: var(--text); }
.profile-links a:hover { color: var(--sea); }
.profile-links .icon { color: var(--slate); font-size: 1rem; }
.home-main { max-width: 720px; }
.intro { font-size: var(--fs-body); line-height: 1.7; color: var(--text); }
.intro p + p { margin-top: 1rem; }
.intro strong { color: var(--ink); font-weight: 600; }

/* Home sections and inner pages sit on white panels over a light canvas */
.profile, .intro, .block { background: var(--paper); border: 1px solid var(--rule); border-radius: 10px; }
.profile { padding: 28px 22px; }
.intro, .block { padding: 24px 28px; }
.home-main { display: grid; gap: 20px; align-content: start; }
.block-head { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; padding-bottom: 10px; margin-bottom: 4px; border-bottom: 1px solid var(--rule); }
.block-head h2 { font-size: var(--fs-md); }
.block-head a, .block-links { font-size: var(--fs-sm); }
.block-links { display: flex; gap: 16px; }

.dated-list { margin: 0; padding: 0; list-style: none; }
.dated-list li { display: grid; grid-template-columns: 88px minmax(0, 1fr) auto; gap: 16px; align-items: baseline; padding: 12px 0; border-bottom: 1px solid var(--rule); }
.dated-list li:last-child { border-bottom: 0; }
.dated-list time, .dated-list .kind { color: var(--slate); font-size: var(--fs-sm); font-variant-numeric: tabular-nums; white-space: nowrap; }
.dated-list a { color: var(--ink); font-weight: 500; }
.dated-list a:hover { color: var(--sea); }

.project-row { display: grid; grid-template-columns: 120px minmax(0, 1fr); gap: 20px; align-items: start; padding: 16px 0; border-bottom: 1px solid var(--rule); }
.project-row:last-child { border-bottom: 0; }
.project-thumb img, .project-thumb span { display: block; width: 120px; height: 80px; border-radius: 4px; object-fit: cover; background: var(--mist); }
.project-thumb span { display: grid; place-items: center; color: var(--slate); font-size: 1.5rem; }
.project-row h3 { font-size: var(--fs-base); }
.project-row h3 a { color: var(--ink); }
.project-row h3 a:hover { color: var(--sea); }
.project-row p { margin-top: 4px; color: var(--slate); font-size: var(--fs-sm); line-height: 1.55; }
.project-row .row-links a { display: inline-flex; align-items: center; gap: 6px; }

/* Publications (home and list) */
.pub-item { padding: 14px 0; border-bottom: 1px solid var(--rule); }
.pub-list .pub-item:last-child { border-bottom: 0; }
.pub-title { font-size: var(--fs-base); font-weight: 500; line-height: 1.45; }
.pub-title a { color: var(--ink); }
.pub-title a:hover { color: var(--sea); }
.pub-venue { display: flex; flex-wrap: wrap; gap: 4px 16px; margin-top: 4px; color: var(--slate); font-size: var(--fs-sm); }
.pub-venue span { font-style: italic; }
.section-subtitle { margin: 48px 0 8px; padding-bottom: 10px; border-bottom: 1px solid var(--rule); font-size: var(--fs-md); }
.bibliography p { margin: 0 0 .9rem; font-size: var(--fs-base); line-height: 1.65; }

/* Inner pages */
.page { margin-block: 40px 64px; padding: 40px 48px 48px; background: var(--paper); border: 1px solid var(--rule); border-radius: 10px; }
.page-header { margin-bottom: 32px; }
.page-title { font-size: var(--fs-lg); letter-spacing: -.015em; }
.page-subtitle { max-width: 640px; margin-top: 8px; color: var(--slate); font-size: var(--fs-body); }
.page-intro { max-width: 640px; margin: -12px 0 32px; color: var(--slate); }
.page-intro p { margin: 0 0 .5rem; }

/* Lists of news, blog posts, and thoughts */
.stream { border-top: 1px solid var(--rule); }
.stream-item { display: grid; grid-template-columns: 112px minmax(0, 1fr) auto; gap: 24px; align-items: start; padding: 22px 0; border-bottom: 1px solid var(--rule); }
.stream-date { padding-top: 2px; color: var(--slate); font-size: var(--fs-sm); font-variant-numeric: tabular-nums; white-space: nowrap; }
.stream-body { min-width: 0; }
.stream-title { font-size: var(--fs-md); line-height: 1.35; letter-spacing: -.005em; }
.stream-title a { color: var(--ink); }
.stream-title a:hover { color: var(--sea); text-decoration: none; }
.stream-summary { display: -webkit-box; -webkit-box-orient: vertical; -webkit-line-clamp: 2; line-clamp: 2; overflow: hidden; margin-top: 6px; color: var(--text); line-height: 1.6; }
.stream-thumb img { display: block; width: 120px; height: 80px; border-radius: 4px; object-fit: cover; background: var(--mist); }
.meta { display: flex; flex-wrap: wrap; gap: 4px 14px; margin-top: 8px; color: var(--slate); font-size: var(--fs-sm); }
.meta:empty { display: none; }
.meta a { color: var(--slate); }
.meta a:hover { color: var(--sea); }

/* Project cards (projects page) */
.card-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 40px 28px; }
.card { display: flex; flex-direction: column; }
.card > .meta { order: 3; margin: 0 0 6px; }
.card-image { order: 1; display: block; margin-bottom: 14px; }
.card-image img, .card-placeholder { display: block; width: 100%; aspect-ratio: 3 / 2; border-radius: 4px; object-fit: cover; background: var(--mist); }
.card-placeholder { display: grid; place-items: center; color: var(--slate); font-size: 2rem; }
.card-title { order: 2; margin-bottom: 4px; font-size: var(--fs-base); }
.card-title a { color: var(--ink); }
.card-title a:hover { color: var(--sea); }
.card-summary { order: 4; color: var(--slate); font-size: var(--fs-sm); line-height: 1.55; }
.card-links { order: 5; margin-top: 8px; font-size: var(--fs-sm); }
.card-links a { display: inline-flex; align-items: center; gap: 6px; }

/* Buttons (project and article links) */
.btn { display: inline-flex; align-items: center; gap: .45em; padding: .45rem 1rem; border: 1px solid var(--sea); border-radius: 4px; font-size: var(--fs-sm); font-weight: 500; line-height: 1.4; }
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--sea); color: var(--on-sea); }
.btn-primary:hover { background: var(--sea-deep); border-color: var(--sea-deep); color: var(--on-sea); }
.btn-outline { background: transparent; color: var(--sea); }
.btn-outline:hover { background: var(--sea); color: var(--on-sea); }
.btn-sm { padding: .25rem .7rem; }
.btn-lg { padding: .6rem 1.3rem; font-size: var(--fs-base); }
.btn-links { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.cta-group { display: flex; flex-wrap: wrap; gap: 12px; }

/* Articles */
.article-container { width: min(796px, 100% - 40px); }
.article-header { margin-bottom: 32px; padding-bottom: 24px; border-bottom: 1px solid var(--rule); }
.article-title { font-size: var(--fs-lg); line-height: 1.25; letter-spacing: -.015em; }
.article-header .meta { margin-top: 12px; }
.article-header .lead { margin-top: 12px; color: var(--slate); font-size: var(--fs-body); }
.prose { font-size: var(--fs-body); line-height: 1.75; }
.prose p { margin: 0 0 1.1rem; }
.prose a { text-decoration: underline; text-decoration-color: color-mix(in srgb, var(--sea) 40%, transparent); text-underline-offset: 3px; }
.prose a:hover { text-decoration-color: currentColor; }
.prose h2 { margin: 2.4rem 0 .8rem; font-size: var(--fs-md); }
.prose h3 { margin: 2rem 0 .6rem; font-size: var(--fs-body); }
.prose h4 { margin: 1.5rem 0 .5rem; font-size: var(--fs-base); }
.prose ul, .prose ol { margin: 0 0 1.1rem; padding-left: 1.4rem; }
.prose li { margin: .3rem 0; }
.prose img { display: block; margin: 1.75rem auto; border-radius: 4px; }
.prose :not(a) > img, .prose a[href$=".webp"] > img, .prose a[href$=".png"] > img, .prose a[href$=".jpg"] > img { cursor: zoom-in; }
.lightbox { position: fixed; inset: 0; z-index: 200; display: flex; overflow: auto; padding: 2vh 2vw; background: rgba(12, 14, 18, .9); cursor: zoom-out; }
.lightbox img { margin: auto; max-width: 100%; max-height: 100%; border-radius: 4px; background: #fff; cursor: zoom-in; }
.lightbox.zoomed img { max-width: none; max-height: none; cursor: zoom-out; }
.prose figure { margin: 1.75rem 0; }
.prose figcaption { color: var(--slate); font-size: var(--fs-sm); text-align: center; }
.prose blockquote { margin: 1.5rem 0; padding: .1rem 0 .1rem 1.1rem; border-left: 3px solid var(--sea); color: var(--slate); }
.prose code { padding: .1em .3em; border-radius: 3px; background: var(--mist); font-family: var(--mono); font-size: .875em; }
.prose pre { overflow-x: auto; padding: 1rem; border: 1px solid var(--rule); border-radius: 4px; background: var(--mist); font-size: var(--fs-sm); line-height: 1.55; }
.prose pre code { padding: 0; background: none; font-size: inherit; }
.prose table { display: block; overflow-x: auto; border-collapse: collapse; font-size: var(--fs-sm); }
.prose th, .prose td { padding: .5rem .75rem; border: 1px solid var(--rule); text-align: left; }
.prose hr { margin: 2rem 0; border: 0; border-top: 1px solid var(--rule); }
.tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 2rem; }
.tags span { padding: .15rem .6rem; border: 1px solid var(--rule); border-radius: 999px; color: var(--slate); font-size: var(--fs-sm); }

/* Pagination (Hugo internal template) */
.pagination { display: flex; flex-wrap: wrap; gap: 6px; margin: 2.5rem 0 0; padding: 0; list-style: none; }
.page-link { display: block; min-width: 36px; padding: .35rem .7rem; border: 1px solid var(--rule); border-radius: 4px; text-align: center; }
.page-item.active .page-link { background: var(--sea); border-color: var(--sea); color: var(--on-sea); }
.page-item.disabled .page-link { color: var(--slate); pointer-events: none; }

/* Search (Pagefind UI) */
#search {
  --pagefind-ui-font: var(--font);
  --pagefind-ui-primary: var(--sea);
  --pagefind-ui-text: var(--text);
  --pagefind-ui-background: var(--paper);
  --pagefind-ui-border: var(--rule);
  --pagefind-ui-tag: var(--mist);
  --pagefind-ui-border-width: 1px;
  --pagefind-ui-border-radius: 4px;
  --pagefind-ui-scale: .9;
}

/* Footer */
.site-footer { border-top: 1px solid var(--rule); color: var(--slate); font-size: var(--fs-sm); }
.footer-inner { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 8px 24px; padding: 28px 0 36px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 6px 20px; }
.site-footer a { color: var(--slate); }
.site-footer a:hover { color: var(--sea); }

/* Responsive */
@media (max-width: 1020px) {
  .site-nav { gap: 18px; }
  .home { grid-template-columns: 232px minmax(0, 1fr); gap: 32px; }
  .profile-photo { width: 128px; height: 128px; }
}
@media (max-width: 900px) {
  .site-nav { display: none; }
  .header-tools { margin-left: auto; }
  .mobile-nav { display: block; }
  .home { display: block; padding-top: 32px; }
  .profile { position: static; display: grid; grid-template-columns: 96px minmax(0, 1fr); gap: 4px 20px; align-items: center; padding: 20px; margin-bottom: 20px; }
  .profile-photo { width: 96px; height: 96px; box-shadow: 0 0 0 1px var(--rule), 0 0 0 4px var(--paper), 0 0 0 5px var(--sea); }
  .profile-id { margin: 0; }
  .profile-name { font-size: var(--fs-md); }
  .profile-role { margin-top: 2px; font-size: var(--fs-sm); }
  .profile-links { grid-column: 1 / -1; display: flex; flex-wrap: wrap; gap: 8px 20px; margin-top: 16px; padding: 0; border: 0; }
  .card-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 600px) {
  .intro, .block { padding: 20px 18px; }
  .home-main { gap: 16px; }
  .dated-list li { grid-template-columns: 72px minmax(0, 1fr); }
  .dated-list .kind { display: none; }
  .project-row { grid-template-columns: 88px minmax(0, 1fr); gap: 14px; }
  .project-thumb img, .project-thumb span { width: 88px; height: 60px; }
  .stream-item { grid-template-columns: minmax(0, 1fr) auto; gap: 6px 16px; }
  .stream-date { grid-column: 1 / -1; padding: 0; }
  .stream-thumb img { width: 88px; height: 60px; }
  .stream-title { font-size: var(--fs-body); }
  .page { margin-block: 16px 40px; padding: 24px 18px 32px; }
  .page-title, .article-title { font-size: 1.625rem; }
  .card-grid { grid-template-columns: 1fr; }
  .prose { font-size: var(--fs-base); }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}

/* Projects without an image: a faint contour map in the accent color instead of an empty box. */
.contour-fill { position: relative; overflow: hidden; background: color-mix(in srgb, var(--sea) 9%, var(--paper)) !important; }
.contour-fill::before { content: ""; position: absolute; inset: 0; background: var(--sea); opacity: .6; -webkit-mask: url("../img/contours.svg") center / cover no-repeat; mask: url("../img/contours.svg") center / cover no-repeat; }