/* ==========================================================================
   Yingda Yu V3 — Researcher × Builder Editorial Portfolio
   Design System & Stylesheet
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Design Tokens
   -------------------------------------------------------------------------- */

:root {
  --bg: #FBF7F2;
  --bg-surface: #FFFFFF;
  --bg-elevated: #FFFFFF;
  --bg-hover: rgba(0, 0, 0, 0.03);
  --bg-venture: rgba(181, 122, 78, 0.04);
  --text: #1A1A2E;
  --text-secondary: #5A5A6E;
  --text-tertiary: #8A8A9E;
  --accent: #B57A4E;
  --accent-dim: rgba(181, 122, 78, 0.1);
  --accent-glow: rgba(181, 122, 78, 0.06);
  --border: rgba(26, 26, 46, 0.08);
  --border-strong: rgba(26, 26, 46, 0.14);
  --font-display: "Newsreader", "Noto Serif SC", Georgia, serif;
  --font-body: "Manrope", "Noto Sans SC", ui-sans-serif, system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
  --max-width: 1100px;
  --nav-height: 72px;
  --side-padding: 24px;
  --t-fast: 200ms ease;
  --t-base: 300ms ease;
  --t-slow: 600ms cubic-bezier(0.22, 1, 0.36, 1);

  /* Spacing scale */
  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 40px;
  --space-xl: 64px;
  --space-2xl: 96px;
}

/* --------------------------------------------------------------------------
   2. Reset & Base
   -------------------------------------------------------------------------- */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 20px);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Focus styles — keyboard accessibility */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 4px;
}

button:focus-visible,
a:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.pub-filter:focus-visible {
  outline-offset: 3px;
}

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

a:hover {
  color: var(--text);
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

ul, ol {
  list-style: none;
}

::selection {
  background: var(--accent-dim);
  color: var(--text);
}

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

/* --------------------------------------------------------------------------
   3. Typography
   -------------------------------------------------------------------------- */

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.2;
  color: var(--text);
}

h1 {
  font-size: clamp(2.8rem, 6vw, 4.5rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.05;
}

h2 {
  font-size: clamp(2.2rem, 4vw, 2.8rem);
  font-weight: 600;
  letter-spacing: -0.015em;
}

h3 {
  font-size: 1.35rem;
  font-weight: 500;
  letter-spacing: -0.01em;
}

p {
  max-width: 70ch;
}

.mono {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.05em;
}

/* --------------------------------------------------------------------------
   4. Layout Helpers
   -------------------------------------------------------------------------- */

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--side-padding);
}

.section {
  padding: var(--space-2xl) 0;
}

.section-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-tertiary);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: var(--space-sm);
}

.section-heading {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 4vw, 2.8rem);
  font-weight: 600;
  margin-bottom: var(--space-lg);
  letter-spacing: -0.015em;
  line-height: 1.15;
}

.section-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: var(--space-md);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--accent);
  letter-spacing: 0.03em;
  transition: gap var(--t-fast);
}

.section-link:hover {
  gap: 12px;
  color: var(--accent);
}

.section-link .arrow {
  transition: transform var(--t-fast);
}

.section-link:hover .arrow {
  transform: translateX(4px);
}

/* --------------------------------------------------------------------------
   5. Navigation
   -------------------------------------------------------------------------- */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 100;
  display: flex;
  align-items: center;
  background: rgba(251, 247, 242, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background var(--t-base), border-color var(--t-base);
}

.nav.scrolled {
  background: rgba(255, 255, 255, 0.95);
  border-bottom-color: var(--border-strong);
}

.nav-inner {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--side-padding);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.02em;
  transition: color var(--t-fast);
}

.nav-logo:hover {
  color: var(--text);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-links a {
  padding: 8px 14px;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: 6px;
  transition: color var(--t-fast), background var(--t-fast);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.lang-toggle {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 6px 12px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-secondary);
  border: 1px solid var(--border-strong);
  border-radius: 6px;
  transition: all var(--t-fast);
  letter-spacing: 0.03em;
}

.lang-toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.lang-toggle .lang-sep {
  color: var(--text-tertiary);
  margin: 0 1px;
}

.lang-toggle .lang-active {
  color: var(--accent);
}

.nav-mobile-toggle {
  display: none;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
  border-radius: 6px;
}

.nav-mobile-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
  transition: transform var(--t-base), opacity var(--t-base);
}

.nav-mobile-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-mobile-toggle.open span:nth-child(2) {
  opacity: 0;
}

.nav-mobile-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* --------------------------------------------------------------------------
   6. Sticky Side Elements
   -------------------------------------------------------------------------- */

.side-social {
  position: fixed;
  left: 40px;
  bottom: 0;
  z-index: 50;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.side-social::after {
  content: "";
  width: 1px;
  height: 60px;
  background: var(--border-strong);
}

.side-social a {
  color: var(--text-secondary);
  transition: color var(--t-fast), transform var(--t-fast);
}

.side-social a:hover {
  color: var(--accent);
  transform: translateY(-3px);
}

.side-social svg {
  width: 18px;
  height: 18px;
}

.side-email {
  position: fixed;
  right: 40px;
  bottom: 0;
  z-index: 50;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.side-email a {
  writing-mode: vertical-rl;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-secondary);
  letter-spacing: 0.05em;
  transition: color var(--t-fast), transform var(--t-fast);
}

.side-email a:hover {
  color: var(--accent);
  transform: translateY(-3px);
}

.side-email::after {
  content: "";
  width: 1px;
  height: 60px;
  background: var(--border-strong);
}

/* --------------------------------------------------------------------------
   7. Hero
   -------------------------------------------------------------------------- */

.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: var(--nav-height);
  background:
    radial-gradient(ellipse 70% 50% at 15% 30%, rgba(181, 122, 78, 0.07), transparent 60%),
    radial-gradient(ellipse 50% 40% at 85% 70%, rgba(200, 160, 120, 0.05), transparent 60%),
    var(--bg);
}

.hero-inner {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--side-padding);
  display: grid;
  grid-template-columns: 42% 58%;
  gap: var(--space-xl);
  align-items: center;
}

.hero-visual {
  display: flex;
  align-items: center;
  justify-content: flex-start;
}

.hero-photo-wrap {
  position: relative;
  width: 100%;
  max-width: 360px;
  aspect-ratio: 4 / 5;
  border-radius: 4px;
  overflow: hidden;
  border: 1px solid var(--border-strong);
  background: var(--bg-surface);
  box-shadow: 0 24px 48px rgba(26, 26, 46, 0.12), 0 8px 16px rgba(26, 26, 46, 0.06);
}

.hero-photo-wrap::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.4);
}

.hero-photo {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  display: block;
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.hero-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--accent);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 4px;
}

.hero-name {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 6vw, 4.5rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.05;
  color: var(--text);
  margin-bottom: var(--space-xs);
}

.hero-name .period {
  color: var(--accent);
}

.hero-statement {
  font-family: var(--font-display);
  font-style: italic;
  font-size: clamp(1.4rem, 2.5vw, 1.8rem);
  font-weight: 400;
  color: var(--text);
  line-height: 1.4;
  max-width: 560px;
  margin-bottom: var(--space-sm);
}

.hero-description {
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 520px;
  line-height: 1.7;
  margin-bottom: var(--space-md);
}

.hero-cta {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
  align-items: center;
  margin-bottom: var(--space-sm);
}

.hero-company-link {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-tertiary);
  letter-spacing: 0.03em;
}

.hero-company-link a {
  color: var(--text-secondary);
  transition: color var(--t-fast);
}

.hero-company-link a:hover {
  color: var(--accent);
}

/* Buttons */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: 0.88rem;
  font-weight: 600;
  font-family: var(--font-body);
  letter-spacing: 0.01em;
  border-radius: 6px;
  transition: all var(--t-base);
}

.btn-primary {
  background: var(--accent);
  color: var(--bg-surface);
}

.btn-primary:hover {
  background: var(--text);
  color: var(--bg-surface);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(181, 122, 78, 0.25);
}

.btn-secondary {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
}

.btn-secondary:hover {
  background: var(--accent-dim);
  transform: translateY(-2px);
}

.btn .arrow {
  transition: transform var(--t-fast);
}

.btn:hover .arrow {
  transform: translateX(4px);
}

/* --------------------------------------------------------------------------
   8. Latest Updates
   -------------------------------------------------------------------------- */

.updates-list {
  display: flex;
  flex-direction: column;
}

.update-item {
  display: grid;
  grid-template-columns: 100px 1fr;
  gap: var(--space-md);
  padding: var(--space-sm) 0;
  border-top: 1px solid var(--border);
  align-items: baseline;
}

.update-item:last-child {
  border-bottom: 1px solid var(--border);
}

.update-date {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent);
  letter-spacing: 0.03em;
  white-space: nowrap;
}

.update-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.update-text strong {
  color: var(--text);
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   9. Publications
   -------------------------------------------------------------------------- */

.pub-list {
  display: flex;
  flex-direction: column;
}

.pub-row {
  display: grid;
  grid-template-columns: 70px 1fr;
  gap: var(--space-md);
  padding: var(--space-md) 0;
  border-top: 1px solid var(--border);
  transition: background var(--t-base);
}

.pub-row:last-child {
  border-bottom: 1px solid var(--border);
}

.pub-row:hover {
  background: var(--bg-hover);
}

.pub-year {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-tertiary);
  letter-spacing: 0.03em;
  padding-top: 4px;
}

.pub-main {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.pub-title {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 500;
  color: var(--text);
  line-height: 1.4;
  transition: color var(--t-fast);
}

.pub-row:hover .pub-title {
  color: var(--accent);
}

.pub-authors {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.pub-authors .author-self {
  font-weight: 700;
  color: var(--accent);
}

.pub-venue {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-tertiary);
  letter-spacing: 0.02em;
}

.pub-badges {
  display: flex;
  gap: 8px;
  margin-top: 4px;
  flex-wrap: wrap;
}

.status-badge {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 3px 10px;
  border-radius: 3px;
  letter-spacing: 0.03em;
  font-weight: 500;
}

.status-published {
  background: var(--accent);
  color: #FFFFFF;
}

.status-accepted {
  background: var(--accent-dim);
  color: var(--accent);
}

.status-preprint {
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
}

.status-under-review {
  background: transparent;
  border: 1px solid var(--text-tertiary);
  color: var(--text-tertiary);
}

.presentation-badge {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  letter-spacing: 0.02em;
}

.pub-links {
  display: flex;
  gap: 16px;
  margin-top: 6px;
  flex-wrap: wrap;
}

.pub-links a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  letter-spacing: 0.02em;
  transition: color var(--t-fast);
}

.pub-links a:hover {
  color: var(--text);
}

.pub-view-all {
  margin-top: var(--space-lg);
  display: flex;
  justify-content: flex-start;
}

.pub-view-all-link {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  letter-spacing: 0.03em;
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid var(--accent-dim);
  padding-bottom: 2px;
  transition: all var(--t-fast);
}

.pub-view-all-link:hover {
  color: var(--text);
  border-bottom-color: var(--text);
}

/* --------------------------------------------------------------------------
   09b. Publications Page (full page)
   -------------------------------------------------------------------------- */

.pub-page-header {
  padding-top: calc(var(--nav-height) + var(--space-xl));
  padding-bottom: var(--space-lg);
  background: var(--bg);
}

.pub-back-link {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  text-decoration: none;
  margin-bottom: var(--space-md);
  letter-spacing: 0.02em;
  transition: color var(--t-fast);
}

.pub-back-link:hover {
  color: var(--accent);
}

.pub-page-title {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  font-weight: 600;
  color: var(--text);
  margin: 0 0 var(--space-sm) 0;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.pub-page-subtitle {
  font-family: var(--font-body);
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin: 0 0 var(--space-md) 0;
  max-width: 600px;
  line-height: 1.6;
}

.pub-count {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-tertiary);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* Filters */
.pub-filters-section {
  padding: var(--space-md) 0;
  position: sticky;
  top: var(--nav-height);
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  z-index: 50;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.pub-filters {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
}

.pub-filter {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.03em;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 100px;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--t-fast);
}

.pub-filter:hover {
  border-color: var(--border-strong);
  color: var(--text);
}

.pub-filter.active {
  background: var(--text);
  border-color: var(--text);
  color: var(--bg);
}

/* Groups */
.pub-main {
  padding: var(--space-xl) 0 var(--space-2xl) 0;
}

.pub-group {
  margin-bottom: var(--space-2xl);
}

.pub-group:last-child {
  margin-bottom: 0;
}

.pub-group-title {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  margin: 0 0 var(--space-md) 0;
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--border);
}

.pub-note {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-tertiary);
  margin: var(--space-xs) 0 0 0;
  letter-spacing: 0.02em;
}

/* --------------------------------------------------------------------------
   10. Research Interests
   -------------------------------------------------------------------------- */

.research-interests-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

.interest-item {
  position: relative;
  padding-left: var(--space-md);
  border-left: 2px solid var(--accent-dim);
  transition: border-color var(--t-base);
}

.interest-item:hover {
  border-left-color: var(--accent);
}

.interest-number {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--accent);
  letter-spacing: 0.08em;
  margin-bottom: var(--space-xs);
}

.interest-item h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 500;
  margin-bottom: var(--space-xs);
  color: var(--text);
}

.interest-detail {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* --------------------------------------------------------------------------
   11. Selected Builds
   -------------------------------------------------------------------------- */

.builds-list {
  display: flex;
  flex-direction: column;
}

.build-item {
  display: grid;
  grid-template-columns: 60px 1fr;
  gap: var(--space-md);
  padding: var(--space-lg) 0;
  border-top: 1px solid var(--border);
  transition: background var(--t-base);
}

.build-item:last-child {
  border-bottom: 1px solid var(--border);
}

.build-item:hover {
  background: var(--bg-hover);
}

.build-number {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--accent);
  padding-top: 4px;
  letter-spacing: 0.03em;
}

.build-body {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.build-body h3 {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 500;
  color: var(--text);
  transition: color var(--t-fast);
  margin-bottom: 2px;
}

.build-item:hover .build-body h3 {
  color: var(--accent);
}

.build-problem {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.build-built {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.build-built strong {
  color: var(--text);
  font-weight: 600;
}

.build-meta {
  display: flex;
  gap: var(--space-sm);
  margin-top: 4px;
  flex-wrap: wrap;
}

.build-meta span {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-tertiary);
  letter-spacing: 0.03em;
}

.build-meta span::before {
  content: "·";
  margin-right: 8px;
  color: var(--border-strong);
}

.build-meta span:first-child::before {
  display: none;
}

/* Venture / Spartina */

.venture {
  background: var(--bg-venture);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.venture-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
  align-items: start;
}

.venture-narrative {
  font-family: var(--font-display);
  font-size: 1.15rem;
  line-height: 1.7;
  color: var(--text);
  font-weight: 400;
}

.venture-narrative .company-name {
  color: var(--accent);
  font-weight: 600;
}

.venture-areas {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.venture-area {
  padding: var(--space-md);
  background: var(--bg-surface);
  border-radius: 8px;
  border: 1px solid var(--border);
  transition: all var(--t-base);
}

.venture-area:hover {
  border-color: var(--accent);
  transform: translateX(4px);
}

.venture-area h4 {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text);
  margin-bottom: 4px;
}

.venture-area p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin: 0;
  line-height: 1.6;
}

.venture-link {
  margin-top: var(--space-lg);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent);
  letter-spacing: 0.03em;
  transition: color var(--t-fast);
}

.venture-link:hover {
  color: var(--text);
}

.venture-link .arrow {
  transition: transform var(--t-fast);
}

.venture-link:hover .arrow {
  transform: translateX(4px);
}

/* --------------------------------------------------------------------------
   12. About & Journey
   -------------------------------------------------------------------------- */

.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-xl);
}

.about-heading {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3.5vw, 2.4rem);
  font-weight: 600;
  color: var(--text);
  margin-bottom: var(--space-md);
  line-height: 1.2;
}

.about-text {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--text-secondary);
  max-width: 680px;
}

.about-text p + p {
  margin-top: var(--space-sm);
}

.about-text strong {
  color: var(--text);
  font-weight: 600;
}

/* Journey Timeline */

.journey-section {
  margin-top: var(--space-xl);
}

.journey-heading {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-tertiary);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: var(--space-md);
}

.timeline {
  position: relative;
  padding-left: var(--space-lg);
}

.timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--border-strong);
}

.timeline-item {
  position: relative;
  padding-bottom: var(--space-lg);
}

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

.timeline-item::before {
  content: "";
  position: absolute;
  left: -37px;
  top: 6px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--accent);
  transition: all var(--t-base);
}

.timeline-item:hover::before {
  background: var(--accent);
  box-shadow: 0 0 12px var(--accent-dim);
}

.timeline-year {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--accent);
  margin-bottom: 4px;
  letter-spacing: 0.03em;
}

.timeline-title {
  font-family: var(--font-body);
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 2px;
}

.timeline-org {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 4px;
}

.timeline-detail {
  font-size: 0.85rem;
  color: var(--text-tertiary);
  max-width: 540px;
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   13. Contact
   -------------------------------------------------------------------------- */

.contact {
  text-align: center;
  padding: var(--space-2xl) 0;
}

.contact-heading {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.contact-sub {
  color: var(--text-secondary);
  font-size: 1rem;
  margin-bottom: var(--space-lg);
  margin-left: auto;
  margin-right: auto;
  max-width: 480px;
}

.contact-email {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 32px;
  font-family: var(--font-mono);
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 6px;
  transition: all var(--t-base);
  margin-bottom: var(--space-xl);
  letter-spacing: 0.02em;
}

.contact-email:hover {
  background: var(--accent-dim);
  transform: translateY(-2px);
}

.contact-socials {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.contact-socials a {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: color var(--t-fast);
  letter-spacing: 0.02em;
}

.contact-socials a:hover {
  color: var(--accent);
}

.contact-socials svg {
  width: 16px;
  height: 16px;
}

/* --------------------------------------------------------------------------
   14. Footer
   -------------------------------------------------------------------------- */

.footer {
  padding: var(--space-lg) 0;
  text-align: center;
  border-top: 1px solid var(--border);
}

.footer-text {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-tertiary);
  letter-spacing: 0.03em;
}

/* --------------------------------------------------------------------------
   15. Section Reveal Animation
   -------------------------------------------------------------------------- */

.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--t-slow), transform var(--t-slow);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-stagger > * {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity var(--t-slow), transform var(--t-slow);
}

.reveal-stagger.visible > * {
  opacity: 1;
  transform: translateY(0);
}

.reveal-stagger.visible > *:nth-child(1) { transition-delay: 0ms; }
.reveal-stagger.visible > *:nth-child(2) { transition-delay: 60ms; }
.reveal-stagger.visible > *:nth-child(3) { transition-delay: 120ms; }
.reveal-stagger.visible > *:nth-child(4) { transition-delay: 180ms; }
.reveal-stagger.visible > *:nth-child(5) { transition-delay: 240ms; }
.reveal-stagger.visible > *:nth-child(6) { transition-delay: 300ms; }
.reveal-stagger.visible > *:nth-child(7) { transition-delay: 360ms; }
.reveal-stagger.visible > *:nth-child(8) { transition-delay: 420ms; }

/* --------------------------------------------------------------------------
   16. Mobile Menu
   -------------------------------------------------------------------------- */

.mobile-menu {
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--bg);
  z-index: 99;
  display: flex;
  flex-direction: column;
  padding: var(--space-xl) var(--side-padding);
  gap: var(--space-sm);
  transform: translateX(100%);
  transition: transform 250ms ease;
}

.mobile-menu.open {
  transform: translateX(0);
}

.mobile-menu a {
  font-family: var(--font-body);
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  transition: color var(--t-fast);
}

.mobile-menu a:hover,
.mobile-menu a.active {
  color: var(--accent);
}

/* --------------------------------------------------------------------------
   17. Responsive
   -------------------------------------------------------------------------- */

/* Desktop: >= 1024px — default styles apply */

/* Tablet: 768px - 1023px */
@media (max-width: 1023px) {
  .side-social,
  .side-email {
    display: none;
  }

  .hero-inner {
    grid-template-columns: 45% 55%;
    gap: var(--space-lg);
  }

  .hero-photo-wrap {
    max-width: 300px;
  }

  .research-interests-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
  }

  .venture-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}

/* Mobile: < 768px */
@media (max-width: 767px) {
  :root {
    --space-2xl: 64px;
    --space-xl: 40px;
    --side-padding: 20px;
  }

  .nav-links {
    display: none;
  }

  .nav-mobile-toggle {
    display: flex;
  }

  .hero {
    min-height: auto;
    padding: calc(var(--nav-height) + 32px) 0 var(--space-xl);
  }

  .hero-inner {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
    text-align: center;
  }

  .hero-visual {
    justify-content: center;
    order: -1;
  }

  .hero-photo-wrap {
    max-width: 240px;
  }

  .hero-content {
    align-items: center;
  }

  .hero-statement,
  .hero-description {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-cta {
    justify-content: center;
  }

  .section-heading {
    font-size: clamp(2rem, 6vw, 2.4rem);
  }

  .research-interests-grid {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }

  .update-item {
    grid-template-columns: 1fr;
    gap: 4px;
    padding: var(--space-sm) 0;
  }

  .update-date {
    order: -1;
  }

  .pub-row {
    grid-template-columns: 1fr;
    gap: var(--space-xs);
    padding: var(--space-sm) 0;
  }

  .pub-year {
    order: -1;
    padding-top: 0;
  }

  .build-item {
    grid-template-columns: 1fr;
    gap: var(--space-xs);
    padding: var(--space-md) 0;
  }

  .build-number {
    order: -1;
    padding-top: 0;
  }

  .venture-area:hover {
    transform: none;
  }

  .timeline {
    padding-left: var(--space-md);
  }

  .timeline-item::before {
    left: -25px;
  }

  .timeline::before {
    left: 4px;
  }

  .pub-page-header {
    padding-top: calc(var(--nav-height) + var(--space-lg));
  }

  .pub-filters-section {
    top: var(--nav-height);
  }

  .pub-filter {
    font-size: 0.72rem;
    padding: 5px 12px;
  }

  .pub-group-title {
    font-size: 0.7rem;
  }
}

/* Small mobile: < 480px */
@media (max-width: 479px) {
  :root {
    --side-padding: 16px;
  }

  .hero-name {
    font-size: 2.5rem;
  }

  .hero-statement {
    font-size: 1.25rem;
  }

  .hero-cta {
    flex-direction: column;
    align-items: stretch;
    width: 100%;
    max-width: 280px;
  }

  .btn {
    justify-content: center;
  }

  .hero-photo-wrap {
    max-width: 200px;
  }

  .contact-socials {
    flex-direction: column;
    align-items: center;
    gap: var(--space-sm);
  }

  .pub-links {
    gap: 12px;
  }

  .build-meta {
    flex-direction: column;
    gap: 2px;
  }

  .build-meta span::before {
    display: none;
  }
}

/* Minimum 375px usable width */
@media (max-width: 375px) {
  :root {
    --side-padding: 14px;
  }

  .hero-name {
    font-size: 2.2rem;
  }

  .section-heading {
    font-size: 1.8rem;
  }
}

/* --------------------------------------------------------------------------
   18. Reduced Motion
   -------------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .reveal,
  .reveal-stagger > * {
    opacity: 1;
    transform: none;
  }
}