/* =========================================================================
   design.css — hzhuang.org redesign
   Dark · Aurora · Glassmorphism · Scroll-driven
   No framework — vanilla CSS only.
   ========================================================================= */

/* ---------- 1. Design tokens ---------- */

:root {
  /* Surfaces (dark by default) */
  --bg: #070817;
  --bg-2: #0c0f24;
  --surface: rgba(255, 255, 255, 0.04);
  --surface-strong: rgba(255, 255, 255, 0.07);
  --border: rgba(255, 255, 255, 0.10);
  --border-strong: rgba(255, 255, 255, 0.18);

  /* Text */
  --text: #f5f5fa;
  --text-muted: #9aa3b8;
  --text-dim: #6c7591;

  /* Accents */
  --accent-1: #06b6d4;
  --accent-2: #a855f7;
  --accent-3: #ec4899;
  --accent-grad: linear-gradient(135deg, var(--accent-1) 0%, var(--accent-2) 50%, var(--accent-3) 100%);
  --accent-grad-soft: linear-gradient(135deg, rgba(6, 182, 212, 0.22), rgba(168, 85, 247, 0.22), rgba(236, 72, 153, 0.22));

  /* Type */
  --font-display: "Space Grotesk", "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Noto Sans CJK SC", "Noto Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: "Inter", "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", "Noto Sans CJK SC", "Noto Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", "Menlo", "PingFang SC", "Microsoft YaHei", monospace;

  /* Layout */
  --max: 1180px;
  --pad-x: clamp(20px, 4vw, 48px);
  --radius: 18px;
  --radius-lg: 28px;

  /* Motion */
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --t-fast: 180ms;
  --t-med: 380ms;
  --t-slow: 720ms;
}

[data-theme="light"] {
  --bg: #f6f7fb;
  --bg-2: #ffffff;
  --surface: rgba(10, 12, 30, 0.04);
  --surface-strong: rgba(10, 12, 30, 0.07);
  --border: rgba(10, 12, 30, 0.10);
  --border-strong: rgba(10, 12, 30, 0.18);
  --text: #0a0d20;
  --text-muted: #4b5572;
  --text-dim: #7a8298;
}

/* ---------- 2. Base ---------- */

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img, svg { display: block; max-width: 100%; }

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--t-fast) var(--ease);
}

a:hover { color: var(--accent-1); }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin: 0 0 0.5em;
}

h1 { font-size: clamp(2.8rem, 7vw, 5.4rem); }
h2 { font-size: clamp(2rem, 4vw, 3.2rem); }
h3 { font-size: clamp(1.25rem, 2vw, 1.55rem); }

p { margin: 0 0 1em; }

::selection {
  background: rgba(168, 85, 247, 0.4);
  color: var(--text);
}

/* Hide content from sighted users but keep it for screen readers */
.sr-only {
  position: absolute !important;
  width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* Skip link */
.skip {
  position: absolute;
  top: -40px;
  left: 16px;
  background: var(--bg-2);
  color: var(--text);
  padding: 10px 16px;
  border-radius: 8px;
  z-index: 1000;
  transition: top var(--t-fast) var(--ease);
}
.skip:focus { top: 16px; }

/* ---------- 3. Background: aurora blobs ---------- */

.aurora {
  position: fixed;
  inset: 0;
  z-index: -2;
  pointer-events: none;
  overflow: hidden;
  background:
    radial-gradient(1200px 800px at 50% -10%, rgba(168, 85, 247, 0.12), transparent 60%),
    var(--bg);
}

.aurora .blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(110px);
  opacity: 0.45;
  will-change: transform;
}

.aurora .blob-1 {
  width: 520px; height: 520px;
  background: radial-gradient(circle, var(--accent-1), transparent 65%);
  top: -160px; left: -120px;
  animation: blob-drift-1 22s ease-in-out infinite alternate;
}
.aurora .blob-2 {
  width: 620px; height: 620px;
  background: radial-gradient(circle, var(--accent-2), transparent 65%);
  top: 30%; right: -160px;
  animation: blob-drift-2 28s ease-in-out infinite alternate;
}
.aurora .blob-3 {
  width: 460px; height: 460px;
  background: radial-gradient(circle, var(--accent-3), transparent 65%);
  bottom: -180px; left: 30%;
  animation: blob-drift-3 26s ease-in-out infinite alternate;
}

@keyframes blob-drift-1 {
  from { transform: translate(0,0) scale(1); }
  to   { transform: translate(140px, 80px) scale(1.15); }
}
@keyframes blob-drift-2 {
  from { transform: translate(0,0) scale(1); }
  to   { transform: translate(-160px, 60px) scale(1.1); }
}
@keyframes blob-drift-3 {
  from { transform: translate(0,0) scale(1); }
  to   { transform: translate(80px, -120px) scale(1.2); }
}

[data-theme="light"] .aurora .blob { opacity: 0.30; }

/* Subtle dotted noise / grid overlay on top of aurora for tactile feel */
.aurora::after {
  content: "";
  position: absolute; inset: 0;
  background-image:
    radial-gradient(rgba(255,255,255,0.05) 1px, transparent 1px);
  background-size: 22px 22px;
  mask-image: radial-gradient(circle at 50% 30%, black, transparent 80%);
  pointer-events: none;
}
[data-theme="light"] .aurora::after {
  background-image: radial-gradient(rgba(10,12,30,0.06) 1px, transparent 1px);
}

/* ---------- 4. Top scroll progress bar ---------- */

.scroll-progress {
  position: fixed;
  top: 0; left: 0;
  height: 2px;
  width: 0%;
  background: var(--accent-grad);
  z-index: 90;
  transition: width 80ms linear;
}

/* ---------- 5. Cursor (only on fine pointers) ---------- */

.cursor-dot, .cursor-ring { display: none; }

@media (hover: hover) and (pointer: fine) {
  .cursor-dot, .cursor-ring {
    position: fixed;
    top: 0; left: 0;
    border-radius: 50%;
    pointer-events: none;
    z-index: 9999;
    mix-blend-mode: difference;
    will-change: transform;
    display: block;
  }
  .cursor-dot {
    width: 6px; height: 6px;
    background: #fff;
    transform: translate(-50%, -50%);
  }
  .cursor-ring {
    width: 36px; height: 36px;
    border: 1px solid rgba(255, 255, 255, 0.7);
    transform: translate(-50%, -50%);
    transition: width var(--t-med) var(--ease), height var(--t-med) var(--ease), border-color var(--t-med) var(--ease);
  }
  body[data-cursor="hover"] .cursor-ring {
    width: 60px; height: 60px;
    border-color: var(--accent-1);
  }
}

/* ---------- 6. Top nav ---------- */

.topnav {
  position: fixed;
  top: 0; left: 0; right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px var(--pad-x);
  z-index: 80;
  transition: backdrop-filter var(--t-med) var(--ease), background var(--t-med) var(--ease), border-color var(--t-med) var(--ease);
  border-bottom: 1px solid transparent;
}

.topnav.scrolled {
  background: color-mix(in srgb, var(--bg) 70%, transparent);
  backdrop-filter: blur(18px) saturate(1.4);
  -webkit-backdrop-filter: blur(18px) saturate(1.4);
  border-bottom-color: var(--border);
}

.topnav .brand {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.1rem;
  letter-spacing: 0.05em;
  background: var(--accent-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.topnav ul {
  list-style: none;
  display: flex;
  gap: 4px;
  margin: 0; padding: 0;
}

.topnav ul a {
  display: inline-block;
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 0.92rem;
  color: var(--text-muted);
  position: relative;
}

.topnav ul a::before {
  content: attr(data-num);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--accent-1);
  margin-right: 6px;
  opacity: 0.7;
}

.topnav ul a:hover { color: var(--text); background: var(--surface); }

.topnav ul a.active {
  color: var(--text);
  background: var(--surface-strong);
}
.topnav ul a.active::before { opacity: 1; }

.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border-radius: 999px;
  border: 1px solid var(--border-strong);
  font-size: 0.92rem;
  font-weight: 500;
  background: var(--surface);
  transition: background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease), transform var(--t-fast) var(--ease);
}

.nav-cta::after {
  content: "→";
  transition: transform var(--t-fast) var(--ease);
}

.nav-cta:hover {
  background: var(--surface-strong);
  border-color: var(--accent-2);
  color: var(--text);
}
.nav-cta:hover::after { transform: translateX(3px); }

.theme-toggle {
  width: 36px; height: 36px;
  border-radius: 50%;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-muted);
  display: inline-flex; align-items: center; justify-content: center;
  cursor: pointer;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}
.theme-toggle:hover { background: var(--surface-strong); color: var(--text); border-color: var(--border-strong); }

.topnav .right { display: flex; align-items: center; gap: 10px; }

@media (max-width: 880px) {
  .topnav ul { display: none; }
}

/* ---------- 7. Side nav (section indicator) ---------- */

.sidenav {
  position: fixed;
  top: 50%; right: 22px;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 14px;
  z-index: 70;
}

.sidenav a {
  position: relative;
  width: 26px; height: 26px;
  display: flex; align-items: center; justify-content: center;
}

.sidenav a .dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--border-strong);
  transition: transform var(--t-med) var(--ease), background var(--t-med) var(--ease);
}

.sidenav a:hover .dot { transform: scale(1.4); background: var(--text); }

.sidenav a.active .dot {
  background: var(--accent-2);
  transform: scale(1.6);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent-2) 25%, transparent);
}

.sidenav a .label {
  position: absolute;
  right: 28px;
  top: 50%;
  transform: translateY(-50%) translateX(4px);
  font-size: 0.78rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  background: var(--surface-strong);
  border: 1px solid var(--border);
  padding: 4px 10px;
  border-radius: 999px;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--t-fast) var(--ease), transform var(--t-fast) var(--ease);
}
.sidenav a:hover .label { opacity: 1; transform: translateY(-50%) translateX(0); }

@media (max-width: 880px) { .sidenav { display: none; } }

/* ---------- 8. Layout shell ---------- */

main { display: block; }

section {
  position: relative;
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(80px, 12vh, 140px) var(--pad-x);
}

.section-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: clamp(28px, 5vw, 56px);
}
.section-head .num {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent-1);
  letter-spacing: 0.1em;
}
.section-head h2 { margin: 0; }
.section-head .sub {
  margin-left: auto;
  color: var(--text-muted);
  font-size: 0.95rem;
  max-width: 360px;
  text-align: right;
}
@media (max-width: 640px) {
  .section-head { flex-direction: column; align-items: flex-start; gap: 8px; }
  .section-head .sub { margin-left: 0; text-align: left; }
}

/* ---------- 9. Hero ---------- */

.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-top: 140px;
  padding-bottom: 80px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.25fr 1fr;
  gap: clamp(40px, 6vw, 100px);
  align-items: center;
}

@media (max-width: 880px) {
  .hero-grid { grid-template-columns: 1fr; }
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 6px 14px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  margin-bottom: 26px;
}

.eyebrow .pulse {
  position: relative;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: #22c55e;
  box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.6);
  animation: pulse 1.8s cubic-bezier(0.66, 0, 0, 1) infinite;
}

@keyframes pulse {
  0%   { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.55); }
  100% { box-shadow: 0 0 0 12px rgba(34, 197, 94, 0); }
}

.hero h1 {
  font-weight: 600;
  margin-bottom: 0.3em;
}

.hero h1 .char {
  display: inline-block;
  opacity: 0;
  filter: blur(8px);
  transform: translateY(28px);
  transition: opacity var(--t-slow) var(--ease), transform var(--t-slow) var(--ease), filter var(--t-slow) var(--ease);
}
.hero h1.is-in .char {
  opacity: 1;
  filter: blur(0);
  transform: translateY(0);
}

.hero .kicker {
  font-family: var(--font-display);
  font-size: clamp(1.15rem, 2vw, 1.5rem);
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.kicker .grad {
  background: var(--accent-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 600;
}

.hero .lede {
  color: var(--text-muted);
  font-size: 1rem;
  max-width: 56ch;
  margin-bottom: 36px;
}

.hero .lede strong { color: var(--text); font-weight: 500; }

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 44px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 22px;
  border-radius: 999px;
  font-weight: 500;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform var(--t-fast) var(--ease), background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease), box-shadow var(--t-med) var(--ease);
  position: relative;
  isolation: isolate;
}

.btn.primary {
  background: var(--accent-grad);
  color: #fff;
  box-shadow: 0 10px 30px -10px rgba(168, 85, 247, 0.55);
}
.btn.primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 18px 40px -10px rgba(168, 85, 247, 0.75);
  color: #fff;
}

.btn.ghost {
  background: var(--surface);
  color: var(--text);
  border-color: var(--border-strong);
}
.btn.ghost:hover { background: var(--surface-strong); border-color: var(--accent-2); transform: translateY(-2px); }

.btn .arrow { transition: transform var(--t-fast) var(--ease); }
.btn:hover .arrow { transform: translateX(4px); }

.hero-stats {
  list-style: none;
  margin: 0; padding: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  max-width: 560px;
}

@media (max-width: 520px) {
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
}

.hero-stats li {
  padding: 16px;
  border-radius: var(--radius);
  background: var(--surface);
  border: 1px solid var(--border);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: border-color var(--t-fast) var(--ease), transform var(--t-fast) var(--ease);
}
.hero-stats li:hover {
  border-color: var(--border-strong);
  transform: translateY(-2px);
}

.hero-stats .num {
  font-family: var(--font-display);
  font-size: 1.85rem;
  font-weight: 700;
  background: var(--accent-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  letter-spacing: -0.02em;
  display: block;
  line-height: 1;
}

.hero-stats .lbl {
  display: block;
  margin-top: 6px;
  color: var(--text-muted);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
}

/* Portrait */

.hero-portrait {
  position: relative;
  display: flex;
  justify-content: center;
}

.portrait-card {
  position: relative;
  width: clamp(240px, 32vw, 360px);
  aspect-ratio: 4 / 5;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--surface-strong);
  border: 1px solid var(--border);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow:
    0 30px 80px -20px rgba(168, 85, 247, 0.35),
    0 10px 40px -10px rgba(6, 182, 212, 0.25);
  transform-style: preserve-3d;
  transition: transform 400ms var(--ease);
  will-change: transform;
}

.portrait-card img {
  width: 100%; height: 100%;
  object-fit: cover;
  filter: saturate(1.05) contrast(1.02);
}

.portrait-card::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 55%, rgba(7, 8, 23, 0.85) 100%);
  pointer-events: none;
}

.portrait-card .status-pill {
  position: absolute;
  left: 16px; bottom: 16px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(7, 8, 23, 0.5);
  border: 1px solid var(--border);
  backdrop-filter: blur(10px);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text);
  z-index: 2;
}
.portrait-card .status-pill .dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: #22c55e;
  animation: pulse 1.8s cubic-bezier(0.66, 0, 0, 1) infinite;
}

/* Floating glow tag */
.float-tag {
  position: absolute;
  padding: 8px 14px;
  border-radius: 999px;
  background: var(--surface-strong);
  border: 1px solid var(--border);
  backdrop-filter: blur(12px);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text);
  white-space: nowrap;
  z-index: 3;
}
.float-tag.t1 { top: -16px; left: -28px; animation: floaty 5s ease-in-out infinite; }
.float-tag.t2 { right: -32px; top: 28%; animation: floaty 6s ease-in-out infinite reverse; }
.float-tag.t3 { left: -36px; bottom: 18%; animation: floaty 7s ease-in-out infinite; }

@keyframes floaty {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-8px); }
}

/* Marquee */

.marquee {
  margin-top: 60px;
  border-block: 1px solid var(--border);
  padding-block: 18px;
  overflow: hidden;
  mask-image: linear-gradient(90deg, transparent, black 8%, black 92%, transparent);
  -webkit-mask-image: linear-gradient(90deg, transparent, black 8%, black 92%, transparent);
}

.marquee-track {
  display: flex;
  gap: 44px;
  width: max-content;
  animation: marquee 36s linear infinite;
  font-family: var(--font-display);
  font-size: 1.05rem;
  color: var(--text-muted);
  letter-spacing: -0.01em;
}

.marquee-track span { display: inline-flex; align-items: center; gap: 10px; }
.marquee-track .dot {
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--accent-2);
  opacity: 0.7;
}

@keyframes marquee {
  from { transform: translateX(0); }
  to   { transform: translateX(-50%); }
}

/* ---------- 10. Glass card primitive ---------- */

.glass {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  overflow: hidden;
}

.glass::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1px;
  background: linear-gradient(135deg, rgba(255,255,255,0.18), transparent 40%, rgba(255,255,255,0.06));
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}

/* ---------- 11. About ---------- */

.about-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 32px;
  align-items: stretch;
}
@media (max-width: 880px) { .about-grid { grid-template-columns: 1fr; } }

.about-card { padding: clamp(28px, 4vw, 44px); }
.about-card .lead {
  font-size: clamp(1.05rem, 1.6vw, 1.2rem);
  color: var(--text);
  line-height: 1.6;
}
.about-card .lead strong {
  color: var(--text);
  background: linear-gradient(180deg, transparent 60%, rgba(168, 85, 247, 0.25) 60%);
}

.about-meta {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  padding: clamp(28px, 4vw, 44px);
}

.meta-row {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 16px;
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border);
  transition: border-color var(--t-fast) var(--ease), background var(--t-fast) var(--ease);
}
.meta-row:hover { border-color: var(--border-strong); background: rgba(255, 255, 255, 0.06); }

.meta-row .icon {
  width: 36px; height: 36px;
  border-radius: 10px;
  background: var(--accent-grad-soft);
  display: flex; align-items: center; justify-content: center;
  color: var(--text);
  font-size: 0.95rem;
}

.meta-row .k { color: var(--text-dim); font-size: 0.78rem; font-family: var(--font-mono); letter-spacing: 0.04em; text-transform: uppercase; }
.meta-row .v { color: var(--text); font-weight: 500; }

/* ---------- 12. Skills bento ---------- */

.bento {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  grid-auto-rows: minmax(140px, auto);
  gap: 18px;
}

.bento-tile {
  position: relative;
  padding: 22px;
  border-radius: var(--radius);
  background: var(--surface);
  border: 1px solid var(--border);
  overflow: hidden;
  transition: border-color var(--t-med) var(--ease), transform var(--t-med) var(--ease), background var(--t-med) var(--ease);
}

.bento-tile::before {
  content: "";
  position: absolute;
  inset: -1px;
  border-radius: inherit;
  padding: 1px;
  background: conic-gradient(from var(--angle, 0deg), transparent 0deg, var(--accent-2) 50deg, transparent 100deg);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0;
  transition: opacity var(--t-med) var(--ease);
  animation: spin-angle 6s linear infinite paused;
}

@keyframes spin-angle {
  from { --angle: 0deg; }
  to   { --angle: 360deg; }
}

.bento-tile:hover {
  background: var(--surface-strong);
  transform: translateY(-3px);
}
.bento-tile:hover::before { opacity: 1; animation-play-state: running; }

.bento-tile .tile-num {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--accent-1);
  letter-spacing: 0.06em;
  opacity: 0.85;
}
.bento-tile h3 {
  margin-top: 8px;
  font-size: 1.15rem;
}
.bento-tile p {
  color: var(--text-muted);
  font-size: 0.92rem;
  margin: 8px 0 14px;
}

.chip-row {
  list-style: none;
  margin: 0; padding: 0;
  display: flex; flex-wrap: wrap;
  gap: 8px;
}
.chip-row li {
  padding: 5px 10px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text);
}

/* Bento spans */
.bento-tile.span-3 { grid-column: span 3; }
.bento-tile.span-2 { grid-column: span 2; }
.bento-tile.span-4 { grid-column: span 4; }
.bento-tile.span-6 { grid-column: span 6; }
.bento-tile.row-2 { grid-row: span 2; }

@media (max-width: 880px) {
  .bento { grid-template-columns: repeat(2, 1fr); }
  .bento-tile.span-3, .bento-tile.span-2, .bento-tile.span-4 { grid-column: span 2; }
  .bento-tile.row-2 { grid-row: auto; }
}

/* ---------- 13. Timeline (Experience / Education) ---------- */

.timeline {
  position: relative;
  list-style: none;
  margin: 0; padding: 0 0 0 28px;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 7px; top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, transparent, var(--border-strong) 8%, var(--border-strong) 92%, transparent);
}

.timeline-item {
  position: relative;
  padding: 0 0 36px 28px;
}

.timeline-item:last-child { padding-bottom: 0; }

.timeline-item::before {
  content: "";
  position: absolute;
  left: -28px; top: 6px;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--accent-2);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent-2) 18%, transparent);
  transition: background var(--t-med) var(--ease), box-shadow var(--t-med) var(--ease);
}

.timeline-item:hover::before { background: var(--accent-2); }

.timeline-card {
  padding: clamp(22px, 3vw, 32px);
}

.timeline-card header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 18px;
  margin-bottom: 12px;
}
.timeline-card .title { margin: 0; font-size: 1.2rem; }
.timeline-card .company { color: var(--accent-1); font-family: var(--font-mono); font-size: 0.85rem; }
.timeline-card .date { margin-left: auto; font-family: var(--font-mono); font-size: 0.78rem; color: var(--text-dim); }

.timeline-card .body { color: var(--text-muted); }
.timeline-card .body strong { color: var(--text); background: linear-gradient(180deg, transparent 65%, rgba(6, 182, 212, 0.28) 65%); }
.timeline-card .body ul { margin: 8px 0 0; padding-left: 1.1em; }
.timeline-card .body li { margin-bottom: 4px; }

/* Edu side-by-side */
.edu-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}
@media (max-width: 880px) { .edu-grid { grid-template-columns: 1fr; } }
.edu-card {
  padding: clamp(22px, 3vw, 32px);
  position: relative;
}
.edu-card .school { font-family: var(--font-mono); font-size: 0.8rem; color: var(--accent-1); letter-spacing: 0.04em; }
.edu-card .degree { margin: 8px 0 4px; font-size: 1.15rem; }
.edu-card .when { color: var(--text-dim); font-family: var(--font-mono); font-size: 0.8rem; margin-bottom: 12px; }

/* ---------- 14. Publications ---------- */

.pub-card {
  padding: clamp(24px, 3.5vw, 36px);
  display: grid;
  grid-template-columns: auto 1fr;
  gap: clamp(20px, 3vw, 32px);
  align-items: center;
}

.pub-card .pub-icon {
  width: 84px; height: 84px;
  border-radius: 20px;
  background: var(--accent-grad-soft);
  display: flex; align-items: center; justify-content: center;
  color: var(--text);
  font-size: 1.6rem;
  flex-shrink: 0;
}

.pub-card .pub-meta {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent-1);
  letter-spacing: 0.05em;
}
.pub-card .pub-title { margin: 8px 0 10px; }
.pub-card .pub-venue { color: var(--text-muted); margin-bottom: 14px; }
.pub-card .pub-links { display: flex; gap: 16px; flex-wrap: wrap; }
.pub-card .pub-links a {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text);
  display: inline-flex; align-items: center; gap: 6px;
}
.pub-card .pub-links a:hover { color: var(--accent-1); }

@media (max-width: 560px) { .pub-card { grid-template-columns: 1fr; } }

/* ---------- 15. Portfolio (tilt cards) ---------- */

.project-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}
@media (max-width: 980px) { .project-row { grid-template-columns: 1fr; } }

.project-card {
  position: relative;
  padding: 26px;
  border-radius: var(--radius-lg);
  background: var(--surface);
  border: 1px solid var(--border);
  overflow: hidden;
  display: flex; flex-direction: column;
  transform-style: preserve-3d;
  transition: border-color var(--t-med) var(--ease), background var(--t-med) var(--ease), box-shadow var(--t-med) var(--ease);
  min-height: 360px;
  will-change: transform;
}

.project-card:hover {
  border-color: var(--border-strong);
  background: var(--surface-strong);
  box-shadow: 0 30px 60px -30px rgba(168, 85, 247, 0.6);
}

.project-card .hero-vis {
  height: 160px;
  border-radius: var(--radius);
  margin-bottom: 18px;
  position: relative;
  overflow: hidden;
  display: flex; align-items: center; justify-content: center;
  font-size: 2.6rem;
  color: rgba(255,255,255,0.9);
  transform: translateZ(20px);
}
.project-card .hero-vis.v-blue   { background: linear-gradient(135deg, #0d47a1 0%, #00838f 50%, #00bcd4 100%); }
.project-card .hero-vis.v-green  { background: linear-gradient(135deg, #00695c 0%, #009688 50%, #4db6ac 100%); }
.project-card .hero-vis.v-image  { background: var(--bg-2); padding: 0; }
.project-card .hero-vis.v-image img {
  width: 100%; height: 100%;
  object-fit: cover;
  border-radius: var(--radius);
}

.project-card .ptag {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--accent-1);
  letter-spacing: 0.05em;
  transform: translateZ(15px);
}
.project-card .ptitle { margin: 8px 0 8px; font-size: 1.15rem; transform: translateZ(15px); }
.project-card .pdesc { color: var(--text-muted); font-size: 0.9rem; flex: 1; transform: translateZ(10px); }
.project-card .pmeta {
  display: flex; flex-wrap: wrap; gap: 6px; margin-top: 16px;
  transform: translateZ(15px);
}
.project-card .pmeta li {
  list-style: none;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 4px 8px;
  border-radius: 6px;
  background: rgba(255,255,255,0.06);
  border: 1px solid var(--border);
  color: var(--text);
}

/* ---------- 16. Contact ---------- */

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: 28px;
  align-items: stretch;
}
@media (max-width: 880px) { .contact-grid { grid-template-columns: 1fr; } }

.contact-info { padding: clamp(28px, 4vw, 44px); display: flex; flex-direction: column; gap: 18px; }

.contact-info .hello {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  margin: 0 0 8px;
}
.contact-info .hello .grad { background: var(--accent-grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.contact-info p { color: var(--text-muted); margin: 0 0 16px; }

.contact-channels { display: grid; gap: 10px; }

.contact-card {
  padding: clamp(28px, 4vw, 44px);
}

.field {
  position: relative;
  margin-bottom: 18px;
}

.field input, .field textarea {
  width: 100%;
  padding: 14px 16px;
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: inherit;
  font-size: 0.95rem;
  outline: none;
  resize: vertical;
  transition: border-color var(--t-fast) var(--ease), background var(--t-fast) var(--ease);
}
.field textarea { min-height: 120px; }

.field input:focus, .field textarea:focus {
  border-color: var(--accent-2);
  background: rgba(255, 255, 255, 0.06);
}

.field label {
  position: absolute;
  left: 14px; top: 14px;
  font-size: 0.95rem;
  color: var(--text-muted);
  pointer-events: none;
  background: var(--bg);
  padding: 0 6px;
  transition: transform var(--t-fast) var(--ease), font-size var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}
.field input:focus + label,
.field input:not(:placeholder-shown) + label,
.field textarea:focus + label,
.field textarea:not(:placeholder-shown) + label {
  transform: translateY(-22px);
  font-size: 0.74rem;
  color: var(--accent-2);
}

.honeypot { position: absolute; left: -5000px; }

/* ---------- 17. Footer ---------- */

.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 120px;
  padding: 40px var(--pad-x) 60px;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.85rem;
}
.site-footer .brand-big {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 6vw, 4.6rem);
  font-weight: 600;
  letter-spacing: -0.04em;
  margin: 0 0 18px;
  background: var(--accent-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  opacity: 0.75;
}
.site-footer ul {
  list-style: none; padding: 0; margin: 0 0 22px;
  display: flex; gap: 14px; justify-content: center;
}
.site-footer ul a {
  width: 40px; height: 40px;
  border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
}
.site-footer ul a:hover { background: var(--surface-strong); border-color: var(--accent-2); color: var(--text); }
.site-footer .meta a { border-bottom: 1px dashed currentColor; }

/* ---------- 18. Reveal-on-scroll ---------- */

.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity var(--t-slow) var(--ease), transform var(--t-slow) var(--ease);
}
.reveal.is-in {
  opacity: 1;
  transform: none;
}

.reveal-stagger > * {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 600ms var(--ease), transform 600ms var(--ease);
  transition-delay: calc(var(--i, 0) * 60ms);
}
.reveal-stagger.is-in > * {
  opacity: 1;
  transform: none;
}

/* ---------- 19. Reduced motion ---------- */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .aurora .blob { animation: none; }
  .marquee-track { animation: none; }
  .reveal, .reveal-stagger > * { opacity: 1; transform: none; }
  .hero h1 .char { opacity: 1; transform: none; filter: none; }
  .cursor-dot, .cursor-ring { display: none !important; }
}

/* ---------- 20. Print ---------- */

@media print {
  .aurora, .cursor-dot, .cursor-ring, .scroll-progress, .topnav, .sidenav, .marquee, .theme-toggle, .lang-toggle, .nav-cta,
  .contact-card, .float-tag, .status-pill {
    display: none !important;
  }
  html, body {
    background: #fff !important;
    color: #111 !important;
  }
  section { padding-block: 24px !important; max-width: none; }
  .hero { min-height: auto !important; padding-top: 0 !important; }
  .hero-grid { grid-template-columns: 1fr !important; }
  .hero-portrait { display: none !important; }
  .hero h1 .char { opacity: 1 !important; transform: none !important; filter: none !important; color: #111 !important; }
  .kicker, .lede, .hero-stats, .eyebrow, .cta-row { color: #333 !important; }
  .glass, .bento-tile, .timeline-card, .edu-card, .pub-card, .project-card {
    background: #fff !important;
    border: 1px solid #ddd !important;
    box-shadow: none !important;
    backdrop-filter: none !important;
  }
  .topnav.scrolled { background: transparent !important; }
  h1, h2, h3, h4 { color: #111 !important; }
  .grad, .brand, .brand-big, .pub-meta, .timeline-card .company, .ptag, .school {
    color: #444 !important;
    background: none !important;
    -webkit-text-fill-color: inherit !important;
  }
  .bento-tile, .timeline-card, .edu-card, .pub-card, .project-card { page-break-inside: avoid; }
}

/* ---------- 21. i18n (zh / en) ---------- */

/* Inline dual-span pattern. Both languages are present in the DOM
   (with their own `lang` attribute for screen-readers / SEO); CSS
   hides whichever one isn't currently active. Default lang on
   <html> is zh-CN, and an early inline script in <head> updates it
   from URL ?lang=, localStorage, or navigator.language before paint. */
html[lang^="zh"] .i18n-en { display: none; }
html[lang="en"]  .i18n-zh { display: none; }

/* CJK micro-typography tweaks (default lang is zh-CN, so this is the
   read-by-default path). Slightly looser line-height and zero negative
   tracking, since CJK glyphs don't benefit from tight tracking. */
html[lang^="zh"] body          { line-height: 1.72; }
html[lang^="zh"] h1,
html[lang^="zh"] h2,
html[lang^="zh"] h3,
html[lang^="zh"] h4            { letter-spacing: 0; }
html[lang^="zh"] .topnav ul a  { font-size: 0.94rem; }

/* Language toggle button (two-state pill in the top nav) */
.lang-toggle {
  display: inline-flex;
  align-items: center;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  transition: background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}
.lang-toggle:hover { background: var(--surface-strong); border-color: var(--border-strong); }

.lang-toggle .opt {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 26px;
  height: 22px;
  padding: 0 8px;
  border-radius: 999px;
  transition: background var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

html[lang^="zh"] .lang-toggle .opt-zh,
html[lang="en"]  .lang-toggle .opt-en {
  background: var(--accent-grad);
  color: #fff;
}

@media (max-width: 880px) {
  .topnav .nav-cta { display: none; }
}