/* Shenqi Zhou: a profile column on the left and one reading column on the right. */

/* Fallback faces tuned to the metrics of DM Sans / DM Serif Display, so the page
   keeps its shape where Google Fonts is slow or blocked. */
@font-face {
  font-family: "DM Sans Fallback";
  src: local("Arial"), local("Helvetica Neue"), local("Helvetica");
  size-adjust: 98%;
  ascent-override: 98%;
  descent-override: 30%;
}
@font-face {
  font-family: "DM Serif Fallback";
  src: local("Georgia"), local("Times New Roman");
  size-adjust: 102%;
}

:root {
  --bg: #f5f7f7;             /* cool paper */
  --text: #1b2325;
  --text-2: #3b484b;
  --muted: #505e61;          /* dates, meta lines (6.3:1 on the page) */
  --nav: #505e61;            /* top-bar links at rest */
  --accent: #2b6f72;         /* deep teal: timeline dots, active nav, the note's rule */
  --link-line: #4f8a8c;      /* link underlines (3.7:1 on the page) */
  --hover: #1c5457;          /* link text on hover (8:1) */
  --note-bg: #e3eded;
  --rule: #dbe2e2;
  --thread: #c3cfcf;         /* the timeline line, a step darker than the hairlines */
  --plate-line: #d6dede;
  --bead-ring: rgb(43 111 114 / .35);
  --photo-line: rgb(0 0 0 / .14);
  --hover-bg: rgb(0 0 0 / .05);

  --photo-w: 200px;          /* width of the profile column */
  --col-gap: 60px;           /* space between the profile column and the reading column */
  --sans: "DM Sans", "DM Sans Fallback", "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --serif: "DM Serif Display", "DM Serif Fallback", Georgia, "Times New Roman", serif;
  --zh: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", serif;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #111a1b;
    --text: #dfe6e5;
    --text-2: #b5c1c0;
    --muted: #8c9b9a;
    --nav: #8c9b9a;
    --accent: #4f9d9b;
    --link-line: rgb(79 157 155 / .8);
    --hover: #92d0cb;
    --note-bg: #162425;
    --rule: #222e30;
    --thread: #324345;
    --plate-line: #222e30;
    --bead-ring: rgb(79 157 155 / .35);
    --photo-line: rgb(255 255 255 / .08);
    --hover-bg: rgb(255 255 255 / .07);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #111a1b;
  --text: #dfe6e5;
  --text-2: #b5c1c0;
  --muted: #8c9b9a;
  --nav: #8c9b9a;
  --accent: #4f9d9b;
  --link-line: rgb(79 157 155 / .8);
  --hover: #92d0cb;
  --note-bg: #162425;
  --rule: #222e30;
  --thread: #324345;
  --plate-line: #222e30;
  --bead-ring: rgb(79 157 155 / .35);
  --photo-line: rgb(255 255 255 / .08);
  --hover-bg: rgb(255 255 255 / .07);
  color-scheme: dark;
}
:root[data-theme="light"] { color-scheme: light; }

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-kerning: normal;
}

h1, h2, h3, p, ul, ol, figure { margin: 0; padding: 0; }
h1, h2, h3 { font-weight: 400; }
ul, ol { list-style: none; }
img { max-width: 100%; }
strong { font-weight: 600; }
.nw { white-space: nowrap; }

/* Links keep the text colour; the accent sits underneath */
a {
  color: var(--text);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-decoration-color: var(--link-line);
  text-underline-offset: 3px;
  transition: color .15s ease, text-decoration-color .15s ease;
}
a:hover { color: var(--hover); text-decoration-color: currentColor; }
.meta a { color: inherit; }               /* adviser links stay in the muted meta colour; the accent line still marks them */
.meta a:hover { color: var(--hover); }
:focus-visible { outline: 2px solid var(--text); outline-offset: 3px; }
[hidden] { display: none !important; }   /* the hidden attribute wins over any display rule */

.skip-link { position: absolute; left: 16px; top: -64px; padding: 6px 12px; background: var(--bg); color: var(--text); z-index: 200; }
.skip-link:focus { top: 8px; }
#main:focus { outline: none; }
#main { scroll-margin-top: 80px; }      /* the skip link moves focus without sliding the name under the bar */

/* Top bar */
.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg);
  border-bottom: 1px solid var(--rule);
}
.topbar-in {
  display: grid;
  grid-template-columns: var(--photo-w) minmax(0, 1fr) auto;   /* same columns and gap as .page, so the links start where the text does */
  column-gap: var(--col-gap);
  align-items: center;
  max-width: 980px;
  margin: 0 auto;
  padding: 19px 40px 18px;
}
.bar-name {
  font-family: var(--serif);
  font-size: 1.3rem;
  line-height: 1.3;
  white-space: nowrap;
  color: var(--text);
  text-decoration: none;
  justify-self: start;
}
.bar-name:hover { color: inherit; }     /* the name stays in ink; only real links take the hover colour */
/* With JS, the small name only appears once the large one has scrolled away */
.watch-name .bar-name { opacity: 0; visibility: hidden; transition: opacity .25s ease, visibility .25s; }
.watch-name .topbar.scrolled .bar-name { opacity: 1; visibility: visible; }

.nav { display: flex; align-items: baseline; gap: 42px; }
.nav a {
  font-family: var(--serif);
  font-size: 1rem;
  line-height: 1.6;
  letter-spacing: .005em;
  color: var(--nav);
  text-decoration: none;
  padding-bottom: 3px;
  background: linear-gradient(var(--accent), var(--accent)) no-repeat 0 100% / 0 2px;
  transition: color .15s ease, background-size .25s ease;
}
.nav a:hover,
.nav a.is-active { color: var(--text); background-size: 100% 2px; }
.mode-btn {
  display: grid;
  place-items: center;
  width: 29px;
  height: 29px;
  margin-right: -6px;
  padding: 0;
  border: 0;
  border-radius: 4px;
  background: transparent;
  color: var(--nav);
  cursor: pointer;
  transition: background-color 120ms linear, color 120ms linear;
}
.mode-btn:hover { background-color: var(--hover-bg); color: var(--text); }
.mode-btn svg { width: 17px; height: 17px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
/* site.js keeps aria-pressed in step with the theme, so the button shows the way back */
.mode-btn[aria-pressed="true"] .ico-moon,
.mode-btn:not([aria-pressed="true"]) .ico-sun { display: none; }
@media (prefers-reduced-motion: reduce) {
  .watch-name .bar-name, .nav a { transition: none; }
}

/* Page grid: profile column left, name and reading column right */
.page {
  display: grid;
  grid-template-columns: var(--photo-w) minmax(0, 1fr);
  grid-template-areas:
    "side hero"
    "side content";
  grid-template-rows: auto 1fr;
  column-gap: var(--col-gap);
  align-items: start;
  max-width: 980px;
  margin: 0 auto;
  padding: 58px 40px 0;
}
.hero { grid-area: hero; scroll-margin-top: 200px; }
.side { grid-area: side; position: relative; }
.content { grid-area: content; min-width: 0; padding-bottom: 96px; }   /* inside the grid, so the sticky column has room at the end */
/* The profile column stays in view. site.js sets --side-top so a column taller than the
   window scrolls until its last line shows, then stops; without JS it only sticks on tall windows. */
@media (min-width: 701px) and (min-height: 800px) {
  html:not(.js) .side { position: sticky; top: 101px; }
}
@media (min-width: 701px) {
  .js .side { position: sticky; top: var(--side-top, 101px); }
}

/* Name block */
.name {
  font-family: var(--serif);
  font-size: 2.75rem;
  line-height: 1.08;
  letter-spacing: -.012em;
  color: var(--text);
  margin-top: -6px;               /* cap height lines up with the top of the photo */
}
.name .zh {
  font-family: var(--zh);
  font-size: 1.15rem;
  letter-spacing: .06em;
  color: var(--muted);
  margin-left: .35em;
  vertical-align: .55em;
}
.affil { margin-top: 12px; font-size: 1rem; line-height: 1.55; color: var(--text-2); }
.affil .sep { color: var(--muted); }

/* The one highlighted line, set like a note in the margin of a notebook */
.note {
  margin-top: 22px;
  padding: .5rem .75rem .5rem .875rem;       /* 12px of air after the 2px rule */
  border-radius: 0 4px 4px 0;
  background: var(--note-bg);
  box-shadow: inset 2px 0 0 var(--accent);      /* the left rule, painted inside the box */
  font-size: .95rem;
  line-height: 1.6;
  color: var(--text);
}

/* Sidebar */
/* Photo card. Front: photo; back: the illustrated avatar. */
.turn-cue {
  position: absolute;
  top: -24px;
  left: 0;
  width: 100%;
  text-align: center;
  font-size: .75rem;
  line-height: 1.5;
  color: var(--muted);
  pointer-events: none;
  transition: opacity .25s ease;
}
html:not(.flip-ready) .turn-cue { display: none; }     /* shown once site.js has wired up the card */
/* on wide screens the column stays in view, so the hint fades once the name has scrolled away */
@media (min-width: 701px) { .topbar.scrolled ~ .page .turn-cue { opacity: 0; } }
.hint-tap { display: none; }
@media (hover: none) { .hint-click { display: none; } .hint-tap { display: inline; } }
.flip {
  display: block;
  position: relative;
  width: 100%;
  aspect-ratio: 4 / 5;
  padding: 0;
  border: 0;
  background: none;
  cursor: pointer;
  perspective: 900px;
  border-radius: 4px;
}
html:not(.flip-ready) .flip { cursor: default; }
.flip-in {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
  transition: transform .7s cubic-bezier(.3, .7, .2, 1);
}
.flip[aria-pressed="true"] .flip-in { transform: rotateY(180deg); }
@media (hover: hover) {                /* a slight tilt hints that the card turns */
  .flip-ready .flip:hover .flip-in { transform: rotateY(-6deg); }
  .flip-ready .flip[aria-pressed="true"]:hover .flip-in { transform: rotateY(186deg); }
}
.face {
  position: absolute;
  inset: 0;
  border-radius: 4px;
  overflow: hidden;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  background: #fff;
}
.face img { display: block; width: 100%; height: 100%; object-fit: cover; object-position: 50% 50%; }
.face::after {                      /* hairline drawn over the image so the white photo has an edge */
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  box-shadow: inset 0 0 0 1px var(--photo-line);
  pointer-events: none;
}
.back { transform: rotateY(180deg); }
@media (prefers-reduced-motion: reduce) {   /* no tilt, and the two sides swap at once */
  .flip-in { transition: none; }
  .flip-ready .flip:hover .flip-in { transform: none; }
  .flip-ready .flip[aria-pressed="true"] .flip-in,
  .flip-ready .flip[aria-pressed="true"]:hover .flip-in { transform: rotateY(180deg); }
}

.timeline { margin-top: 20px; padding-left: 3px; }
.timeline li {
  position: relative;
  padding: 0 0 10px 21px;
  font-size: .8125rem;
  line-height: 1.5;
  color: var(--text-2);
}
.timeline li::before {             /* the dot: a small bead with a paler ring */
  content: "";
  position: absolute;
  left: 0;
  top: 5px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--accent);
  outline: 1px solid var(--bead-ring);
  outline-offset: 2.5px;
}
.timeline li:not(:last-child)::after {   /* the thread, from just under one ring to just above the next */
  content: "";
  position: absolute;
  left: 4px;
  top: 18px;
  bottom: -1px;
  width: 1px;
  background: var(--thread);
}
.timeline li:last-child { padding-bottom: 0; }
.yr { font-weight: 500; color: var(--text); font-variant-numeric: tabular-nums; margin-right: .2em; }

.records, .contact { margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--rule); }

/* Grades and scholarships: the item in ink, the detail in grey underneath */
.records li { font-size: .8125rem; line-height: 1.45; color: var(--text); }
.records li + li { margin-top: 9px; }
.records .rk { font-weight: 500; }
.records .rs { display: none; }
.records .rd { display: block; color: var(--muted); font-variant-numeric: tabular-nums; }

.contact { font-size: .8125rem; line-height: 1.5; }
.contact li + li { margin-top: 7px; }
.contact a {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  color: var(--text-2);
  text-decoration: none;
}
.contact a span { text-decoration: underline; text-decoration-color: transparent; text-underline-offset: 3px; transition: text-decoration-color .15s; }
.contact a:hover { color: var(--hover); }
.contact a:hover span { text-decoration-color: currentColor; }
.contact svg { flex: 0 0 auto; width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }

/* Reading column */
.bio { margin-top: 26px; }
.bio p { margin-bottom: 16px; }
.bio p:last-child { margin-bottom: 0; }

.sec { margin-top: 56px; }
.sec > h2 {
  font-family: var(--serif);
  font-size: 1.5rem;
  line-height: 1.2;
  letter-spacing: -.005em;
  color: var(--text);
  margin-bottom: 18px;
}
section[id], .entry { scroll-margin-top: 96px; }

.pub-title { font-size: 1.0625rem; font-weight: 500; line-height: 1.45; color: var(--text); text-wrap: balance; }
.authors { margin-top: 5px; font-size: .875rem; line-height: 1.55; color: var(--muted); }
.authors strong { color: var(--text); font-weight: 600; }
.status { font-size: .875rem; line-height: 1.55; color: var(--muted); }
.pub-title a { color: inherit; text-decoration: none; }
.pub-title a:hover { color: var(--hover); text-decoration: underline; text-decoration-color: var(--link-line); }
.pub-links { margin-top: 4px; font-size: .875rem; line-height: 1.55; }
.pub-links .sep { color: var(--muted); }
.text { margin-top: 10px; }

/* Figure 1 sits on a white plate with a hairline, never inverted */
.fig { margin-top: 24px; }
.plate {
  display: block;
  background: #fff;
  border: 1px solid var(--plate-line);
  border-radius: 4px;
  padding: 12px 14px;
  transition: border-color .15s ease;   /* the plate links to the full-size figure; the accent edge marks it on hover */
}
.plate:hover { border-color: var(--accent); }
.plate img { display: block; width: 100%; height: auto; }
.fig figcaption {
  margin-top: 10px;
  font-size: .875rem;
  font-style: normal;
  line-height: 1.55;
  color: var(--muted);
}
.fig-n { color: var(--text); font-weight: 500; margin-right: .15em; }
/* In the dark theme only the white figure plate is toned down; the photo is never filtered */
:root[data-theme="dark"] .plate { filter: brightness(.9); }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .plate { filter: brightness(.9); }
}

/* Entries: research, projects, education */
.entry + .entry { margin-top: 32px; }
.entry-head { display: flex; align-items: baseline; justify-content: space-between; gap: 2px 24px; }
.entry h3 { font-size: 1.0625rem; font-weight: 500; line-height: 1.45; }
.date {
  flex: 0 0 auto;
  font-size: .8125rem;
  line-height: 1.5;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}
.meta { margin-top: 2px; font-size: .875rem; line-height: 1.55; color: var(--muted); }
.entry .text + .text { margin-top: 10px; }
/* Courses and Programming: detail lines, a step quieter than the prose and kept as a pair */
.courses { font-size: .9375rem; line-height: 1.6; color: var(--text-2); }
.entry .courses + .courses { margin-top: 6px; }

/* Short lines only: on long paragraphs "pretty" makes the right edge more ragged, so they rely on the   in the text */
.news dd, .fig figcaption { text-wrap: pretty; }
.entry h3 { text-wrap: balance; }

.news { margin: 0; }
.news-row { display: flex; align-items: baseline; gap: 1rem; font-size: .9375rem; line-height: 1.55; }
.news-row + .news-row { margin-top: .5rem; }
.news dt { flex: 0 0 5.25rem; white-space: nowrap; color: var(--muted); font-size: .8125rem; font-variant-numeric: tabular-nums; }
.news dd { flex: 1 1 auto; min-width: 0; margin: 0; }

/* Footer */
.foot {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 40px;
}
.foot p {
  border-top: 1px solid var(--rule);
  padding: 20px 0 28px;
  font-size: .8125rem;
  line-height: 1.6;
  color: var(--muted);
  text-align: center;
}
.foot .sep { padding: 0 .1em; }

/* Medium screens */
@media (max-width: 900px) {
  :root { --col-gap: 44px; }
  .topbar-in, .page { padding-left: 28px; padding-right: 28px; }
  .foot { padding: 0 28px; }
  .nav { gap: 26px; }
  .name { font-size: 2.5rem; }
}
@media (max-width: 1000px) {              /* the two roles stack before the line would wrap around the dot */
  .affil .sep { display: none; }
  .affil > .nw { display: block; white-space: normal; }
  .affil .nw .nw { white-space: nowrap; }
}

/* Narrow reading column: dates go under the titles */
@media (max-width: 820px) {
  .entry-head { flex-direction: column; gap: 0; }
  .entry-head .date { order: 2; }
}

/* Phones */
@media (max-width: 700px) {
  .topbar { position: static; }
  .topbar-in { grid-template-columns: 1fr auto; column-gap: 0; padding: 12px 18px; }
  .bar-name { display: none; }
  .nav { gap: 22px; }
  .nav a { font-size: .95rem; }

  .page { display: block; padding: 30px 18px 56px; }
  .content { padding-bottom: 0; }
  .name { font-size: 2.2rem; margin-top: 0; }
  .name .zh { font-size: 1.05rem; }
  .affil { margin-top: 8px; font-size: .9375rem; }
  .affil > .nw:last-child { margin-top: 4px; }   /* a small step between the two roles */
  .note { margin-top: 16px; }

  .side {
    margin-top: 46px;
    display: grid;
    grid-template-columns: 124px minmax(0, 1fr);
    column-gap: 18px;
    align-items: start;
  }
  .turn-cue { width: 124px; top: -24px; }
  .flip { grid-column: 1; grid-row: 1; }
  .timeline { grid-column: 2; grid-row: 1; margin-top: 2px; }
  /* grades under the photo, scholarships under the timeline */
  .records {
    grid-column: 1 / -1;
    grid-row: 2;
    display: grid;
    grid-template-columns: 124px minmax(0, 1fr);
    gap: 9px 18px;
    margin-top: 20px;
    padding-top: 14px;
  }
  .records li + li { margin-top: 0; }
  .records li:nth-child(n+3) { grid-column: 2; }   /* every scholarship stays in the right column */
  .contact {
    grid-column: 1 / -1;
    grid-row: 3;
    display: flex;
    flex-wrap: wrap;
    gap: 6px 24px;
    margin-top: 14px;
    padding-top: 14px;
  }
  .contact li + li { margin-top: 0; }

  .bio { margin-top: 30px; }
  .sec { margin-top: 44px; }
  .sec > h2 { font-size: 1.375rem; margin-bottom: 14px; }
  section[id], .entry { scroll-margin-top: 12px; }
  .plate { padding: 8px; }
  .news-row { gap: .75rem; }
  .news dt { flex-basis: 4.375rem; }
  .foot { padding: 0 18px; }
}
@media (max-width: 480px) {
  .foot .sep { display: none; }
  .foot .nw { display: block; }
}
@media (max-width: 374px) {
  /* too narrow for the timeline beside the photo: the records go beside it, the timeline below */
  .side { grid-template-columns: 100px minmax(0, 1fr); column-gap: 14px; }
  .turn-cue { width: 100px; }
  .records { grid-column: 2; grid-row: 1; align-self: center; display: block; margin-top: 0; padding-top: 0; border-top: 0; }
  .records li:nth-child(n+3) { grid-column: auto; }
  .records li + li { margin-top: 8px; }
  .timeline { grid-column: 1 / -1; grid-row: 2; margin-top: 20px; padding-top: 16px; border-top: 1px solid var(--rule); }
  .contact { grid-row: 3; }
}

@media (max-width: 359px) {
  .nav { gap: 12px; }               /* four links fit on one line at 320px */
  .nav a { font-size: .875rem; }
  .name { font-size: 2rem; }
}

/* Print and Save as PDF: dark ink on white in either theme, the real photo only */
@media print {
  :root, :root:not([data-theme="light"]), :root[data-theme="dark"] {
    --bg: #fff; --text: #111; --text-2: #333; --muted: #555; --accent: #2b6f72;
    --link-line: #2b6f72; --note-bg: #fff; --rule: #ccc; --plate-line: #ccc;
    --photo-line: rgb(0 0 0 / .14); color-scheme: light;
  }
  .topbar, .mode-btn, .turn-cue, .skip-link { display: none !important; }
  .side { position: static !important; }
  .flip-in { transform: none !important; transition: none !important; }
  .face.back { display: none !important; }
  .plate { filter: none !important; }
  .fig, .news-row, .pub-title, .entry h3, .entry-head, .records li { break-inside: avoid; }
  .sec > h2, .pub-title, .authors, .entry-head, .entry h3, .meta { break-after: avoid; }
}