/* ============================================================
   xiaoyuchen — The Geometry of Data
   Design tokens, themes, layout, motion
   ============================================================ */

/* ---------- Tokens ---------- */
:root {
  --font-display: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "Segoe UI", Roboto, sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", "Segoe UI", Roboto, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "SFMono-Regular", Menlo, "Cascadia Mono", Consolas, monospace;

  --max-w: 1180px;
  --radius: 14px;
  --radius-sm: 8px;
  --ease: cubic-bezier(.22,.61,.36,1);

  /* canvas palette — graphics always render on a dark panel, in BOTH themes,
     so strokes and accents keep the same high contrast everywhere */
  --cv-text: #EEF3F6;
  --cv-muted: #96A6B5;
  --cv-faint: #6E7E8D;
  --cv-amber: #4DA3FF;
  --cv-teal: #3BD5C3;
  --cv-rose: #FF7B98;
  --cv-surface: #16202E;
  --cv-hairline: rgba(238, 243, 246, .22);
}

:root, html[data-theme="dark"] {
  --bg: #0C1118;
  --bg-2: #101724;
  --surface: #151D2A;
  --surface-2: #1B2434;
  --text: #EEF3F6;
  --muted: #93A3B2;
  --faint: #5E6C7A;
  --hairline: rgba(238, 243, 246, .10);
  --hairline-strong: rgba(238, 243, 246, .20);
  --amber: #4DA3FF;
  --teal: #3BD5C3;
  --rose: #FF7B98;
  --amber-soft: rgba(77, 163, 255, .15);
  --teal-soft: rgba(59, 213, 195, .12);
  --rose-soft: rgba(255, 123, 152, .13);
  --shadow: 0 20px 50px -18px rgba(0,0,0,.55);
  --grid-line: rgba(238,243,246,.04);
  --glass-bg: rgba(21, 29, 42, .52);
  --glass-border: rgba(255, 255, 255, .12);
  --glass-inset: rgba(255, 255, 255, .07);
  --neu-hi: rgba(255, 255, 255, .05);
  --neu-sh: rgba(0, 0, 0, .55);
  --neu-primary-bg: rgba(255, 255, 255, .15);
  --neu-primary-text: #EEF3F6;
  --neu-thumb: #C6D0DB;
  --blob-1: rgba(77, 163, 255, .13);
  --blob-2: rgba(59, 213, 195, .11);
  --blob-3: rgba(255, 123, 152, .08);
  color-scheme: dark;
}

html[data-theme="light"] {
  /* neumorphic glass — cool light gray, tactile, calm */
  --bg: #E2E4E8;
  --bg-2: #D9DCE1;
  --surface: #F5F6F8;
  --surface-2: #E9EBEF;
  --text: #35383B;
  --muted: #696E74;
  --faint: #999EA4;
  --hairline: rgba(53, 56, 59, .09);
  --hairline-strong: rgba(53, 56, 59, .16);
  --amber: #54718E;
  --teal: #557C74;
  --rose: #9A5F6D;
  --amber-soft: rgba(84, 113, 142, .12);
  --teal-soft: rgba(85, 124, 116, .12);
  --rose-soft: rgba(154, 95, 109, .11);
  --shadow: 0 18px 40px -20px rgba(125, 132, 140, .35);
  --grid-line: rgba(53,56,59,.035);
  --glass-bg: rgba(255, 255, 255, .58);
  --glass-border: rgba(255, 255, 255, .88);
  --glass-inset: rgba(255, 255, 255, .98);
  --neu-hi: rgba(255, 255, 255, .95);
  --neu-sh: rgba(118, 126, 136, .34);
  --neu-primary-bg: rgba(255, 255, 255, .92);
  --neu-primary-text: #35383B;
  --neu-thumb: #FFFFFF;
  --blob-1: rgba(255, 255, 255, .55);
  --blob-2: rgba(168, 176, 186, .22);
  --blob-3: rgba(184, 191, 200, .24);
  /* canvas palette for light theme — dark ink on white glass, like a printed figure */
  --cv-text: #2E3236;
  --cv-muted: #4F565E;
  --cv-faint: #878E96;
  --cv-amber: #2F6BA8;
  --cv-teal: #177F6D;
  --cv-rose: #C24862;
  --cv-surface: #FFFFFF;
  --cv-hairline: rgba(46, 50, 54, .25);
  color-scheme: light;
}

/* ---------- Base ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  transition: background .45s var(--ease), color .45s var(--ease);
  overflow-x: hidden;
}
::selection { background: var(--amber); color: #fff; }

a { color: var(--teal); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 700; letter-spacing: -.02em; line-height: 1.12; margin: 0; }

.mono { font-family: var(--font-mono); }

.wrap { max-width: var(--max-w); margin: 0 auto; padding: 0 clamp(20px, 4vw, 44px); }

/* faint blueprint grid on the page background */
body::before {
  content: "";
  position: fixed; inset: 0; z-index: -2;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 56px 56px;
  pointer-events: none;
}

/* soft color blobs — the atmosphere the liquid glass panels blur over */
body::after {
  content: "";
  position: fixed; inset: -15%; z-index: -3;
  background:
    radial-gradient(38% 34% at 18% 20%, var(--blob-1), transparent 70%),
    radial-gradient(34% 32% at 84% 12%, var(--blob-2), transparent 70%),
    radial-gradient(42% 38% at 72% 86%, var(--blob-3), transparent 70%),
    radial-gradient(30% 28% at 8% 78%, var(--blob-2), transparent 70%);
  pointer-events: none;
  transition: background .45s var(--ease);
}

/* ---------- Nav ---------- */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  border-bottom: 1px solid var(--hairline);
  transition: background .45s var(--ease);
}
.nav-inner {
  max-width: var(--max-w); margin: 0 auto;
  padding: 0 clamp(20px, 4vw, 44px);
  display: flex; align-items: center; gap: 18px;
  height: 60px;
}
.monogram {
  font-family: var(--font-display);
  font-size: 21px; font-weight: 620;
  color: var(--text);
  display: flex; align-items: center; gap: 10px;
}
.monogram svg { display: block; }
.monogram:hover { text-decoration: none; }
.nav-links { display: flex; gap: 4px; margin-left: auto; align-items: center; flex-wrap: wrap; }
.nav-links a {
  font-family: var(--font-mono); font-size: 12.5px; letter-spacing: .04em;
  color: var(--muted); padding: 7px 10px; border-radius: 7px;
  transition: color .2s, background .2s;
}
.nav-links a:hover { color: var(--text); background: var(--surface-2); text-decoration: none; }
.nav-links a.active { color: var(--amber); }

.theme-toggle {
  margin-left: 6px;
  width: 38px; height: 38px; border-radius: 50%;
  border: 1px solid var(--hairline-strong);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  display: grid; place-items: center;
  transition: transform .3s var(--ease), background .3s;
}
.theme-toggle:hover { transform: rotate(24deg) scale(1.06); }
.theme-toggle svg { width: 17px; height: 17px; }
html[data-theme="dark"] .icon-sun { display: none; }
html[data-theme="light"] .icon-moon { display: none; }

/* mobile nav */
.nav-burger { display: none; }
@media (max-width: 960px) {
  .nav-links {
    display: none;
    position: absolute; top: 60px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--hairline);
    padding: 8px 16px 14px;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 11px 10px; font-size: 14px; }
  .nav-burger {
    display: grid; place-items: center;
    margin-left: auto;
    width: 38px; height: 38px;
    background: none; border: 1px solid var(--hairline-strong);
    border-radius: 8px; color: var(--text); cursor: pointer;
  }
  .theme-toggle { margin-left: 0; }
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex; align-items: center;
  overflow: hidden;
}
#hero-canvas {
  position: absolute; inset: 0;
  width: 100%; height: 100%;
  z-index: 0;
}
.hero::after { /* bottom fade into page */
  content: "";
  position: absolute; left: 0; right: 0; bottom: 0; height: 26vh;
  background: linear-gradient(transparent, var(--bg));
  z-index: 1; pointer-events: none;
}
.hero-content { position: relative; z-index: 2; padding-top: 60px; }
.hero-kicker {
  font-family: var(--font-mono);
  font-size: 13px; letter-spacing: .18em; text-transform: uppercase;
  color: var(--amber);
  margin-bottom: 20px;
  display: flex; align-items: center; gap: 14px;
}
.hero-kicker::before { content: ""; width: 44px; height: 1px; background: var(--amber); display: inline-block; }
.hero h1 {
  font-size: clamp(3rem, 8.5vw, 6.2rem);
  letter-spacing: -.015em;
  font-variation-settings: "opsz" 100;
}
.hero-sub {
  margin-top: 22px;
  max-width: 560px;
  font-size: clamp(1.05rem, 1.6vw, 1.25rem);
  color: var(--muted);
}
.hero-sub strong { color: var(--text); font-weight: 500; }
.hero-affil {
  margin-top: 10px;
  font-family: var(--font-mono); font-size: 13.5px; color: var(--faint);
}
.hero-chips { margin-top: 34px; display: flex; gap: 12px; flex-wrap: wrap; }
.chip {
  font-family: var(--font-mono); font-size: 13px;
  padding: 10px 18px;
  border: 1px solid var(--hairline-strong);
  border-radius: 999px;
  color: var(--text);
  background: color-mix(in srgb, var(--surface) 65%, transparent);
  transition: border-color .25s, transform .25s var(--ease), background .25s;
  display: inline-flex; align-items: center; gap: 8px;
}
.chip:hover { border-color: var(--amber); transform: translateY(-2px); text-decoration: none; }
.chip.primary { background: var(--amber); border-color: var(--amber); color: #fff; font-weight: 500; }
.chip.primary:hover { transform: translateY(-2px) scale(1.02); }

.scroll-cue {
  position: absolute; bottom: 30px; left: 50%; transform: translateX(-50%);
  z-index: 2; color: var(--faint);
  font-family: var(--font-mono); font-size: 11px; letter-spacing: .22em;
  text-transform: uppercase;
  display: flex; flex-direction: column; align-items: center; gap: 10px;
}
.scroll-cue::after {
  content: ""; width: 1px; height: 42px;
  background: linear-gradient(var(--faint), transparent);
  animation: cue 2.2s var(--ease) infinite;
}
@keyframes cue { 0% { transform: scaleY(0); transform-origin: top; } 45% { transform: scaleY(1); transform-origin: top; } 55% { transform: scaleY(1); transform-origin: bottom; } 100% { transform: scaleY(0); transform-origin: bottom; } }

/* ---------- Sections ---------- */
section.block { padding: clamp(72px, 10vw, 128px) 0; position: relative; }
section.block + section.block { border-top: 1px solid var(--hairline); }

.sec-head { display: flex; align-items: baseline; gap: 22px; margin-bottom: clamp(34px, 5vw, 60px); flex-wrap: wrap; }
.sec-num {
  font-family: var(--font-mono); font-size: 13px; color: var(--amber);
  letter-spacing: .14em;
  padding: 5px 11px; border: 1px solid var(--amber);
  border-radius: 999px;
  background: var(--amber-soft);
}
.sec-head h2 { font-size: clamp(1.9rem, 4vw, 3rem); letter-spacing: -.01em; }
.sec-head .sec-note { font-family: var(--font-mono); font-size: 13px; color: var(--faint); margin-left: auto; }

/* reveal on scroll */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
.reveal.visible { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .scroll-cue::after { animation: none; }
  html { scroll-behavior: auto; }
}

/* ---------- About ---------- */
.about-grid { display: grid; grid-template-columns: 0.9fr 1.4fr; gap: clamp(30px, 5vw, 70px); align-items: start; }
@media (max-width: 900px) { .about-grid { grid-template-columns: 1fr; } }

.portrait-card {
  position: relative;
  border: 1px solid var(--hairline-strong);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow);
  overflow: hidden;
  aspect-ratio: 4/4.6;
}
.portrait-card canvas { width: 100%; height: 100%; display: block; }
.portrait-card .portrait-photo { width: 100%; height: 100%; object-fit: cover; display: block; }
.portrait-card .badge {
  position: absolute; left: 16px; bottom: 14px;
  font-family: var(--font-mono); font-size: 11.5px; color: var(--muted);
  letter-spacing: .06em;
}

.about-copy p { margin: 0 0 1.1em; font-size: 1.06rem; }
.about-copy .lede { font-size: 1.28rem; line-height: 1.5; color: var(--text); font-family: var(--font-display); font-weight: 480; }

.timeline { margin-top: 34px; display: grid; gap: 0; }
.timeline h3 { font-size: 1.05rem; color: var(--amber); margin-bottom: 12px; font-family: var(--font-mono); font-weight: 500; letter-spacing: .1em; text-transform: uppercase; font-size: .8rem; }
.tl-item {
  display: grid; grid-template-columns: 92px 1fr; gap: 18px;
  padding: 11px 0;
  border-top: 1px dashed var(--hairline);
  font-size: .98rem;
}
.tl-item .when { font-family: var(--font-mono); font-size: 12.5px; color: var(--faint); padding-top: 3px; }
.tl-item .what strong { font-weight: 600; }
.tl-item .what span { color: var(--muted); display: block; font-size: .92rem; }

/* honors strip */
.honors { margin-top: 40px; display: grid; gap: 10px; }
.honor {
  display: flex; gap: 14px; align-items: baseline;
  padding: 12px 16px;
  background: var(--surface);
  border: 1px solid var(--hairline);
  border-left: 3px solid var(--amber);
  border-radius: var(--radius-sm);
  font-size: .95rem;
}
.honor .yr { font-family: var(--font-mono); font-size: 12px; color: var(--amber); white-space: nowrap; }

/* ---------- Research themes ---------- */
.themes { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
@media (max-width: 900px) { .themes { grid-template-columns: 1fr; } }
.theme-card {
  position: relative;
  border: 1px solid var(--hairline-strong);
  border-radius: var(--radius);
  background: linear-gradient(160deg, var(--surface), var(--bg-2));
  padding: 30px 28px 28px;
  overflow: hidden;
  transition: transform .35s var(--ease), border-color .35s;
}
.theme-card:hover { transform: translateY(-6px); border-color: var(--teal); }
.theme-card .t-icon { height: 72px; margin-bottom: 18px; }
.theme-card h3 { font-size: 1.32rem; margin-bottom: 12px; }
.theme-card p { color: var(--muted); font-size: .97rem; margin: 0; }
.theme-card .t-tags { margin-top: 18px; display: flex; flex-wrap: wrap; gap: 7px; }
.t-tag {
  font-family: var(--font-mono); font-size: 11px;
  color: var(--teal); background: var(--teal-soft);
  padding: 4px 10px; border-radius: 999px;
}

/* ---------- Demo gallery (subsection of Research) ---------- */
.demo-sub {
  margin-top: clamp(56px, 8vw, 100px);
  border-top: 1px dashed var(--hairline);
  padding-top: clamp(40px, 6vw, 70px);
}
.demos-head { max-width: 640px; margin-bottom: clamp(10px, 2vw, 26px); }
.demos-head h3 {
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  margin-bottom: 12px;
}
.demos-head p { color: var(--muted); font-size: 1.02rem; margin: 0; }

.demo {
  display: grid; grid-template-columns: 1.25fr 1fr;
  gap: clamp(26px, 4vw, 54px);
  align-items: center;
  padding: clamp(40px, 6vw, 70px) 0;
}
.demo + .demo { border-top: 1px dashed var(--hairline); }
.demo:nth-child(even) .demo-canvas-wrap { order: 2; }
@media (max-width: 960px) {
  .demo { grid-template-columns: 1fr; }
  .demo:nth-child(even) .demo-canvas-wrap { order: 0; }
}

.demo-canvas-wrap {
  position: relative;
  border: 1px solid var(--hairline-strong);
  border-radius: var(--radius);
  background:
    radial-gradient(120% 90% at 20% 10%, color-mix(in srgb, var(--surface-2) 70%, transparent), transparent),
    var(--surface);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.demo-canvas-wrap canvas { display: block; width: 100%; height: auto; touch-action: none; cursor: grab; }
.demo-canvas-wrap canvas:active { cursor: grabbing; }
.demo-canvas-wrap .corner {
  position: absolute; top: 12px; left: 14px;
  font-family: var(--font-mono); font-size: 11px; letter-spacing: .08em;
  color: var(--faint); pointer-events: none;
}

.demo-copy .paper-tag {
  display: inline-block;
  font-family: var(--font-mono); font-size: 11.5px; letter-spacing: .07em;
  color: var(--amber); background: var(--amber-soft);
  border: 1px solid color-mix(in srgb, var(--amber) 40%, transparent);
  padding: 5px 12px; border-radius: 999px;
  margin-bottom: 16px;
}
.demo-copy h3 { font-size: clamp(1.5rem, 2.6vw, 2.05rem); margin-bottom: 14px; }
.demo-copy p { color: var(--muted); font-size: 1rem; margin: 0 0 12px; }
.demo-copy p strong { color: var(--text); font-weight: 550; }

.demo-controls { display: flex; flex-wrap: wrap; gap: 10px 16px; margin-top: 18px; align-items: center; }
.ctl-btn {
  font-family: var(--font-mono); font-size: 12.5px;
  padding: 9px 16px;
  border-radius: 8px;
  border: 1px solid var(--hairline-strong);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  transition: border-color .2s, background .2s, transform .15s;
}
.ctl-btn:hover { border-color: var(--amber); transform: translateY(-1px); }
.ctl-btn.primary { background: var(--amber); color: #fff; border-color: var(--amber); font-weight: 500; }
.ctl-btn[aria-pressed="true"] { border-color: var(--teal); color: var(--teal); background: var(--teal-soft); }

.ctl-slider { display: flex; align-items: center; gap: 10px; font-family: var(--font-mono); font-size: 12px; color: var(--muted); }
.ctl-slider input[type="range"] {
  appearance: none; -webkit-appearance: none;
  width: 130px; height: 3px; border-radius: 3px;
  background: var(--hairline-strong);
  outline: none;
}
.ctl-slider input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 15px; height: 15px; border-radius: 50%;
  background: var(--amber); border: 2px solid var(--bg);
  cursor: pointer;
  box-shadow: 0 0 0 1px var(--amber);
}
.ctl-slider input[type="range"]::-moz-range-thumb {
  width: 13px; height: 13px; border-radius: 50%;
  background: var(--amber); border: 2px solid var(--bg);
  cursor: pointer;
}
.ctl-slider .val { min-width: 38px; color: var(--amber); text-align: right; }

.demo-cite {
  font-family: var(--font-mono);
  font-size: 12px !important;
  line-height: 1.6;
  color: var(--faint) !important;
  margin-top: 16px !important;
  padding-left: 12px;
  border-left: 2px solid var(--hairline-strong);
}
.demo-cite a { color: var(--teal); }

details.demo-more { margin-top: 16px; border-top: 1px dashed var(--hairline); padding-top: 12px; }
details.demo-more summary {
  cursor: pointer; font-family: var(--font-mono); font-size: 12.5px;
  color: var(--teal); letter-spacing: .04em; list-style: none;
}
details.demo-more summary::before { content: "▸ "; }
details.demo-more[open] summary::before { content: "▾ "; }
details.demo-more p { font-size: .92rem; margin-top: 10px; }

.demo-legend { display: flex; flex-wrap: wrap; gap: 8px 18px; margin-top: 14px; font-family: var(--font-mono); font-size: 11.5px; color: var(--muted); }
.demo-legend .key { display: inline-flex; align-items: center; gap: 7px; }
.demo-legend .swatch { width: 11px; height: 11px; border-radius: 50%; display: inline-block; }

/* ---------- Publications ---------- */
.pub-tools { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; margin-bottom: 28px; }
.pub-filters { display: flex; gap: 8px; flex-wrap: wrap; }
.pub-filter {
  font-family: var(--font-mono); font-size: 12.5px;
  padding: 8px 15px; border-radius: 999px;
  border: 1px solid var(--hairline-strong);
  background: transparent; color: var(--muted);
  cursor: pointer; transition: all .2s;
}
.pub-filter:hover { color: var(--text); border-color: var(--text); }
.pub-filter.active { background: var(--amber); border-color: var(--amber); color: #fff; font-weight: 500; }
.pub-search {
  margin-left: auto;
  font-family: var(--font-mono); font-size: 13px;
  background: var(--surface); color: var(--text);
  border: 1px solid var(--hairline-strong); border-radius: 999px;
  padding: 9px 18px; min-width: 220px;
  outline: none;
  transition: border-color .2s;
}
.pub-search:focus { border-color: var(--teal); }
.pub-search::placeholder { color: var(--faint); }
@media (max-width: 700px) { .pub-search { margin-left: 0; width: 100%; } }

.pub-list { display: grid; gap: 12px; }
.pub {
  display: grid; grid-template-columns: 64px 1fr;
  gap: 18px;
  padding: 18px 20px;
  border: 1px solid var(--hairline);
  border-radius: var(--radius-sm);
  background: var(--surface);
  transition: border-color .25s, transform .25s var(--ease);
}
.pub:hover { border-color: var(--hairline-strong); transform: translateX(4px); }
.pub.selected { border-left: 3px solid var(--amber); }
.pub .pub-year { font-family: var(--font-mono); font-size: 13px; color: var(--amber); padding-top: 3px; }
.pub .pub-title { font-weight: 600; font-size: 1.02rem; line-height: 1.4; }
.pub .pub-authors { color: var(--muted); font-size: .9rem; margin-top: 4px; }
.pub .pub-authors .me { color: var(--text); font-weight: 600; }
.pub .pub-venue { font-family: var(--font-mono); font-size: 12px; color: var(--teal); margin-top: 6px; }
.pub .pub-badges { display: inline-flex; gap: 7px; margin-left: 8px; vertical-align: 2px; }
.pub-badge {
  font-family: var(--font-mono); font-size: 10.5px;
  background: var(--rose-soft); color: var(--rose);
  border: 1px solid color-mix(in srgb, var(--rose) 40%, transparent);
  padding: 2px 9px; border-radius: 999px; white-space: nowrap;
}
.pub-badge.gold { background: var(--amber-soft); color: var(--amber); border-color: color-mix(in srgb, var(--amber) 45%, transparent); }
.pub-count { font-family: var(--font-mono); font-size: 12px; color: var(--faint); margin-top: 18px; }
.pub-note { font-family: var(--font-mono); font-size: 12px; color: var(--faint); margin-bottom: 20px; }
@media (max-width: 640px) { .pub { grid-template-columns: 1fr; gap: 6px; } }

/* ---------- Students ---------- */
.stu-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(255px, 1fr)); gap: 16px; }
.stu-card {
  border: 1px solid var(--hairline);
  border-radius: var(--radius-sm);
  background: var(--surface);
  padding: 20px 20px 18px;
  transition: border-color .25s, transform .25s var(--ease);
  position: relative;
}
.stu-card:hover { border-color: var(--teal); transform: translateY(-3px); }
.stu-card .stu-deg { font-family: var(--font-mono); font-size: 11px; color: var(--teal); letter-spacing: .08em; text-transform: uppercase; }
.stu-card h4 { font-size: 1.12rem; margin: 7px 0 6px; }
.stu-card p { margin: 0; color: var(--muted); font-size: .88rem; line-height: 1.5; }
.stu-card .stu-when { font-family: var(--font-mono); font-size: 11px; color: var(--faint); margin-top: 10px; }
.stu-card.alum { opacity: .82; }
.stu-card.alum::after {
  content: "ALUM"; position: absolute; top: 14px; right: 14px;
  font-family: var(--font-mono); font-size: 9.5px; letter-spacing: .12em;
  color: var(--faint); border: 1px solid var(--hairline-strong);
  padding: 2px 7px; border-radius: 999px;
}
.subhead {
  font-family: var(--font-mono); font-size: .78rem; letter-spacing: .12em;
  text-transform: uppercase; color: var(--amber);
  margin: 40px 0 16px;
}
.subhead:first-child { margin-top: 0; }
.stu-awards { display: grid; gap: 8px; }
.stu-award { display: flex; gap: 12px; align-items: baseline; font-size: .93rem; color: var(--muted); padding: 8px 0; border-top: 1px dashed var(--hairline); }
.stu-award .who { color: var(--text); font-weight: 550; white-space: nowrap; }

/* ---------- Teaching ---------- */
.courses { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 16px; }
.course {
  border: 1px solid var(--hairline);
  border-radius: var(--radius-sm);
  background: var(--surface);
  padding: 22px;
}
.course .c-code { font-family: var(--font-mono); font-size: 12px; color: var(--amber); letter-spacing: .06em; }
.course h4 { font-size: 1.08rem; margin: 6px 0 4px; }
.course .c-terms { font-family: var(--font-mono); font-size: 11.5px; color: var(--faint); }
.rating { margin-top: 16px; display: grid; gap: 9px; }
.rating .r-row { display: grid; grid-template-columns: 88px 1fr 34px; align-items: center; gap: 10px; font-family: var(--font-mono); font-size: 11px; color: var(--muted); }
.r-bar { height: 5px; border-radius: 4px; background: var(--hairline); position: relative; overflow: visible; }
.r-bar .fill {
  position: absolute; left: 0; top: 0; bottom: 0; border-radius: 4px;
  background: linear-gradient(90deg, var(--teal), var(--amber));
  width: 0;
  transition: width 1.1s var(--ease) .15s;
}
.r-bar .avg-tick { position: absolute; top: -3px; bottom: -3px; width: 2px; background: var(--faint); border-radius: 2px; }
.r-val { color: var(--amber); text-align: right; }
.rating-note { font-family: var(--font-mono); font-size: 10.5px; color: var(--faint); margin-top: 12px; }
.course.uofl-note { display: flex; flex-direction: column; justify-content: center; }
.course.uofl-note p { color: var(--muted); font-size: .93rem; margin: 8px 0 0; }

/* ---------- Service ---------- */
.svc-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
@media (max-width: 960px) { .svc-grid { grid-template-columns: 1fr; } }
.svc-col h3 { font-family: var(--font-mono); font-size: .8rem; letter-spacing: .12em; text-transform: uppercase; color: var(--amber); margin-bottom: 16px; font-weight: 500; }
.svc-item { padding: 10px 0; border-top: 1px dashed var(--hairline); font-size: .93rem; }
.svc-item .role { font-weight: 600; }
.svc-item .org { color: var(--muted); display: block; font-size: .88rem; }
.svc-item .when { font-family: var(--font-mono); font-size: 11px; color: var(--faint); }
.svc-tags { display: flex; flex-wrap: wrap; gap: 7px; margin-top: 6px; }
.svc-tags .t-tag { color: var(--muted); background: var(--surface-2); }

/* ---------- Back to top ---------- */
#to-top {
  position: fixed;
  right: 22px;
  bottom: 22px;
  z-index: 95;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  border: 1px solid var(--hairline-strong);
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  color: var(--text);
  cursor: pointer;
  display: grid;
  place-items: center;
  box-shadow: var(--shadow);
  opacity: 0;
  transform: translateY(14px);
  pointer-events: none;
  transition: opacity .35s var(--ease), transform .35s var(--ease), border-color .2s;
}
#to-top.show { opacity: 1; transform: none; pointer-events: auto; }
#to-top:hover { border-color: var(--amber); color: var(--amber); }

/* ---------- Footer ---------- */
footer {
  border-top: 1px solid var(--hairline);
  padding: clamp(48px, 7vw, 90px) 0 40px;
  position: relative;
  overflow: hidden;
}
.foot-grid { display: grid; grid-template-columns: 1.3fr 1fr; gap: 40px; align-items: end; }
@media (max-width: 800px) { .foot-grid { grid-template-columns: 1fr; } }
.foot-grid h2 { font-size: clamp(1.7rem, 3.6vw, 2.6rem); margin-bottom: 18px; }
.foot-contact { font-family: var(--font-mono); font-size: 13.5px; color: var(--muted); line-height: 2; }
.foot-contact a { color: var(--teal); }
.foot-meta {
  margin-top: 46px; padding-top: 22px;
  border-top: 1px dashed var(--hairline);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px;
  font-family: var(--font-mono); font-size: 11.5px; color: var(--faint);
}

/* ============================================================
   Liquid Glass — translucent, blurred, softly lit panels
   ============================================================ */
.theme-card,
.demo-canvas-wrap,
.portrait-card,
.pub,
.stu-card,
.honor,
.pub-search,
.ctl-btn,
.pub-filter,
.chip,
#to-top,
.theme-toggle,
.nav-burger {
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(24px) saturate(1.6);
  backdrop-filter: blur(24px) saturate(1.6);
  border-color: var(--glass-border);
  box-shadow:
    -10px -10px 22px var(--neu-hi),
    12px 14px 28px var(--neu-sh),
    inset 0 1px 0 var(--glass-inset);
}
.theme-card, .demo-canvas-wrap, .portrait-card { border-radius: 28px; }
.pub, .stu-card, .honor { border-radius: 22px; }
.chip, .pub-search, .pub-filter, .ctl-btn { border-radius: 999px; }

/* primary controls: brighter raised glass (neumorphic, not colored fill) */
.chip.primary,
.ctl-btn.primary,
.pub-filter.active {
  background: var(--neu-primary-bg);
  border-color: var(--glass-border);
  color: var(--neu-primary-text);
  font-weight: 600;
  box-shadow:
    -8px -8px 18px var(--neu-hi),
    10px 12px 22px var(--neu-sh),
    inset 0 1px 0 var(--glass-inset);
}
.chip.primary:hover, .ctl-btn.primary:hover { border-color: var(--glass-border); }

/* hover: glass brightens slightly */
.theme-card:hover, .pub:hover, .stu-card:hover, .chip:hover, .ctl-btn:hover {
  background: color-mix(in srgb, var(--glass-bg) 70%, var(--surface-2));
}

/* graphics panels in light theme: same white glass as every other card,
   with the canvases drawing dark ink strokes via the light --cv-* palette;
   a brighter opaque fill keeps the figures crisp over the page blobs */
html[data-theme="light"] .demo-canvas-wrap,
html[data-theme="light"] .portrait-card {
  background: linear-gradient(165deg, #FFFFFF 0%, #F7F8FA 60%, #F2F3F6 100%);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

/* mobile nav panel gets the glass treatment too (more opaque for legibility) */
@media (max-width: 960px) {
  .nav-links {
    background: color-mix(in srgb, var(--bg) 88%, transparent);
    -webkit-backdrop-filter: blur(28px) saturate(1.8);
    backdrop-filter: blur(28px) saturate(1.8);
    box-shadow: 0 22px 40px -22px rgba(0,0,0,.35);
  }
}

/* ============================================================
   Mobile / tablet refinements
   ============================================================ */
@media (max-width: 700px) {
  body { font-size: 16px; }

  /* sliders stretch to full row width for comfortable touch targets */
  .demo-controls { gap: 12px; }
  .ctl-slider { flex: 1 1 100%; }
  .ctl-slider input[type="range"] { flex: 1; width: auto; min-width: 0; }
  .ctl-btn { padding: 11px 16px; }   /* ≥44px touch target */

  .portrait-card { max-width: 340px; margin: 0 auto; }
  .demo { padding: 36px 0; gap: 20px; }
  .demo-canvas-wrap .corner { font-size: 10px; }
  .hero-chips .chip { padding: 11px 16px; }
  .sec-head { gap: 14px; }
  .foot-contact { font-size: 12.5px; }
  #to-top { right: 14px; bottom: 14px; width: 44px; height: 44px; }
}

/* iOS momentum + prevent accidental horizontal scroll */
@media (max-width: 960px) {
  .wrap { padding-left: 18px; padding-right: 18px; }
}

/* ============================================================
   Neumorphic controls — tactile grooves and pressed states
   ============================================================ */
/* softer display weights, echoing the neumorphic reference */
h1, h2, h3, h4 { font-weight: 620; }
.hero h1 { font-weight: 320; letter-spacing: .012em; }

/* pressed / toggled controls sink into the surface */
.ctl-btn:active, .chip:active, .pub-filter:active, #to-top:active, .theme-toggle:active {
  transform: none;
  box-shadow:
    inset 4px 4px 10px var(--neu-sh),
    inset -4px -4px 9px var(--neu-hi);
}
.ctl-btn[aria-pressed="true"] {
  background: color-mix(in srgb, var(--glass-bg) 65%, var(--bg));
  box-shadow:
    inset 4px 4px 10px var(--neu-sh),
    inset -4px -4px 9px var(--neu-hi);
}

/* sliders: debossed groove + extruded thumb */
.ctl-slider input[type="range"] {
  height: 6px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--bg) 82%, var(--neu-sh));
  box-shadow:
    inset 2px 2px 5px var(--neu-sh),
    inset -2px -2px 4px var(--neu-hi);
}
.ctl-slider input[type="range"]::-webkit-slider-thumb {
  width: 20px; height: 20px;
  background: var(--neu-thumb);
  border: none;
  box-shadow: 2px 3px 7px var(--neu-sh), -2px -2px 5px var(--neu-hi);
}
.ctl-slider input[type="range"]::-moz-range-thumb {
  width: 18px; height: 18px;
  background: var(--neu-thumb);
  border: none;
  box-shadow: 2px 3px 7px var(--neu-sh), -2px -2px 5px var(--neu-hi);
}
.ctl-slider .val { color: var(--text); }

/* search field: debossed like a carved groove */
.pub-search {
  background: color-mix(in srgb, var(--bg) 88%, var(--neu-sh));
  border-color: transparent;
  box-shadow:
    inset 3px 3px 7px var(--neu-sh),
    inset -3px -3px 6px var(--neu-hi);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}
.pub-search:focus { border-color: var(--glass-border); }