/* ============================================================
   PERSONAL RESEARCH WEBSITE — MAIN STYLESHEET
   Aesthetic: Refined editorial minimalism
   Fonts: Playfair Display (serif) + DM Mono (code) + Instrument Sans (UI)
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,400;0,500;0,700;1,400;1,500&family=Instrument+Sans:wght@300;400;500;600&family=DM+Mono:ital,wght@0,300;0,400;1,300&display=swap');

/* ── Variables ── */
:root {
  --ink:        #1a1a18;
  --ink-light:  #5c5c58;
  --ink-faint:  #9c9c96;
  --paper:      #faf9f6;
  --paper-warm: #f3f1eb;
  --border:     #e2e0d8;
  --accent:     #2d5016;
  --accent-2:   #8b3a1a;
  --highlight:  #f0ebe0;

  --font-serif: 'Playfair Display', Georgia, serif;
  --font-sans:  'Instrument Sans', system-ui, sans-serif;
  --font-mono:  'DM Mono', 'Courier New', monospace;

  --max-w:      780px;
  --wide-w:     1100px;
  --gap:        clamp(1.5rem, 4vw, 3rem);

  --ease-out:   cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 17px; }
body {
  font-family: var(--font-sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { cursor: pointer; border: none; background: none; font: inherit; }

/* ── Page Loader ── */
#page-loader {
  position: fixed; inset: 0;
  background: var(--paper);
  display: flex; align-items: center; justify-content: center;
  z-index: 9999;
  transition: opacity 0.6s var(--ease-out), visibility 0.6s;
}
#page-loader.hidden { opacity: 0; visibility: hidden; pointer-events: none; }
.loader-line {
  width: 120px; height: 1px;
  background: var(--border);
  position: relative;
  overflow: hidden;
}
.loader-line::after {
  content: '';
  position: absolute; left: -100%; top: 0;
  width: 100%; height: 100%;
  background: var(--ink);
  animation: loaderSlide 0.9s var(--ease-out) forwards;
}
@keyframes loaderSlide { to { left: 100%; } }

/* ── Navigation ── */
nav#main-nav {
  position: fixed; top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 0 var(--gap);
  height: 64px;
  display: flex; align-items: center; justify-content: space-between;
  background: rgba(250, 249, 246, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s, background 0.3s;
}
nav#main-nav.scrolled { border-color: var(--border); }

.nav-brand {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--ink);
  transition: opacity 0.2s;
}
.nav-brand:hover { opacity: 0.6; }
.nav-brand span { font-style: italic; font-weight: 400; }

.nav-links {
  display: flex; gap: 2rem;
  list-style: none;
}
.nav-links a {
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-light);
  transition: color 0.2s;
  position: relative;
}
.nav-links a::after {
  content: '';
  position: absolute; bottom: -2px; left: 0; right: 0;
  height: 1px; background: var(--ink);
  transform: scaleX(0); transform-origin: left;
  transition: transform 0.3s var(--ease-out);
}
.nav-links a:hover, .nav-links a.active { color: var(--ink); }
.nav-links a:hover::after, .nav-links a.active::after { transform: scaleX(1); }

.nav-hamburger {
  display: none; flex-direction: column; gap: 5px;
  width: 24px; padding: 4px 0;
}
.nav-hamburger span {
  display: block; height: 1px; background: var(--ink);
  transition: transform 0.3s, opacity 0.3s;
}
.nav-hamburger.open span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.nav-mobile {
  display: none;
  position: fixed; top: 64px; left: 0; right: 0; bottom: 0;
  background: var(--paper);
  padding: 3rem var(--gap);
  z-index: 99;
  flex-direction: column; gap: 2rem;
  opacity: 0; transform: translateY(-8px);
  transition: opacity 0.3s, transform 0.3s;
  pointer-events: none;
}
.nav-mobile.open {
  display: flex; opacity: 1; transform: translateY(0); pointer-events: all;
}
.nav-mobile a {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-style: italic;
  color: var(--ink-light);
  transition: color 0.2s;
}
.nav-mobile a:hover { color: var(--ink); }

/* ── Layout Helpers ── */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 var(--gap);
}
.container-wide {
  max-width: var(--wide-w);
  margin: 0 auto;
  padding: 0 var(--gap);
}
.pt-nav { padding-top: 64px; }
section { padding: clamp(3rem, 8vw, 6rem) 0; }

/* ── Typography ── */
h1, h2, h3, h4 {
  font-family: var(--font-serif);
  line-height: 1.2;
  font-weight: 500;
  letter-spacing: -0.02em;
}
h1 { font-size: clamp(2.4rem, 5vw, 4rem); }
h2 { font-size: clamp(1.8rem, 3.5vw, 2.6rem); }
h3 { font-size: clamp(1.3rem, 2.5vw, 1.7rem); }
h4 { font-size: 1.1rem; }

p { margin-bottom: 1.4em; color: var(--ink-light); }
p:last-child { margin-bottom: 0; }

.lead {
  font-size: clamp(1rem, 2vw, 1.2rem);
  line-height: 1.8;
  color: var(--ink-light);
}

.label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

/* ── Dividers ── */
.divider {
  width: 40px; height: 1px;
  background: var(--ink);
  margin: 1.5rem 0;
}
hr { border: none; border-top: 1px solid var(--border); margin: 3rem 0; }

/* ── Buttons ── */
.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.7em 1.6em;
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border: 1px solid var(--ink);
  color: var(--ink);
  transition: background 0.2s, color 0.2s;
}
.btn:hover { background: var(--ink); color: var(--paper); }
.btn-ghost {
  border-color: var(--border);
  color: var(--ink-light);
}
.btn-ghost:hover { border-color: var(--ink); color: var(--ink); background: none; }

/* ── Tags ── */
.tag {
  display: inline-block;
  padding: 0.25em 0.75em;
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  background: var(--paper-warm);
  border: 1px solid var(--border);
  color: var(--ink-light);
  transition: background 0.2s, border-color 0.2s, color 0.2s;
}
.tag:hover, .tag.active { background: var(--ink); border-color: var(--ink); color: var(--paper); }

/* ── Cards ── */
.post-card {
  padding: 2rem 0;
  border-bottom: 1px solid var(--border);
  display: grid;
  gap: 0.75rem;
  transition: opacity 0.2s;
}
.post-card:first-child { border-top: 1px solid var(--border); }
.post-card:hover { opacity: 0.75; }
.post-card .meta {
  display: flex; gap: 1.5rem; align-items: center; flex-wrap: wrap;
}
.post-card h3 {
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  transition: color 0.2s;
}
.post-card:hover h3 { color: var(--accent); }
.post-card .excerpt { font-size: 0.92rem; margin: 0; }
.post-card .tags { display: flex; gap: 0.5rem; flex-wrap: wrap; }

/* ── Hero ── */
#hero {
  min-height: 92vh;
  display: flex; align-items: center;
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--border);
}
.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: end;
  padding-bottom: 6rem;
}
.hero-text { padding-top: 2rem; }
.hero-name {
  font-family: var(--font-serif);
  font-size: clamp(3rem, 7vw, 5.5rem);
  font-weight: 500;
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin-bottom: 1.5rem;
}
.hero-name em {
  font-style: italic;
  color: var(--ink-light);
}
.hero-tagline {
  font-size: clamp(0.95rem, 1.8vw, 1.1rem);
  color: var(--ink-light);
  max-width: 36ch;
  margin-bottom: 2.5rem;
}
.hero-links {
  display: flex; gap: 1rem; flex-wrap: wrap;
}
.hero-visual {
  display: flex; flex-direction: column; gap: 1rem;
  align-self: center;
}
.hero-eq {
  background: var(--paper-warm);
  border: 1px solid var(--border);
  padding: 2rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--ink-light);
  position: relative;
}
.hero-eq .eq-label {
  font-size: 0.68rem; font-weight: 600; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--ink-faint);
  margin-bottom: 1rem;
}
.hero-stats {
  display: grid; grid-template-columns: repeat(3, 1fr);
  border: 1px solid var(--border);
}
.hero-stat {
  padding: 1.25rem;
  border-right: 1px solid var(--border);
}
.hero-stat:last-child { border-right: none; }
.hero-stat .num {
  font-family: var(--font-serif);
  font-size: 1.8rem;
  font-weight: 500;
  letter-spacing: -0.03em;
}
.hero-stat .desc { font-size: 0.72rem; color: var(--ink-faint); margin: 0; }

.hero-scroll {
  position: absolute; bottom: 2rem; left: 50%;
  transform: translateX(-50%);
  display: flex; flex-direction: column; align-items: center; gap: 0.5rem;
  font-size: 0.7rem; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--ink-faint);
  animation: scrollBounce 2s ease-in-out infinite;
}
.hero-scroll::after {
  content: '';
  width: 1px; height: 40px;
  background: linear-gradient(to bottom, var(--ink-faint), transparent);
}
@keyframes scrollBounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(4px); }
}

/* ── Tag Cloud Section ── */
#tag-cloud-section {
  padding: 4rem 0;
  border-bottom: 1px solid var(--border);
  background: var(--paper-warm);
}
#tag-cloud-canvas {
  width: 100%;
  height: 260px;
  position: relative;
  overflow: hidden;
}
.floating-tag {
  position: absolute;
  font-family: var(--font-sans);
  font-weight: 500;
  color: var(--ink-light);
  cursor: pointer;
  white-space: nowrap;
  transition: color 0.2s, opacity 0.2s;
  user-select: none;
}
.floating-tag:hover { color: var(--accent); }
.floating-tag.dim { opacity: 0.25; }

/* ── Featured Posts ── */
#featured-posts { padding: clamp(4rem, 8vw, 7rem) 0; }
.section-header {
  display: flex; justify-content: space-between; align-items: baseline;
  margin-bottom: 3rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}
.section-header h2 { font-size: clamp(1.4rem, 2.5vw, 1.8rem); }

/* ── Image Gallery Preview ── */
#gallery-preview {
  padding: clamp(4rem, 8vw, 7rem) 0;
  background: var(--paper-warm);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
}
.gallery-item {
  position: relative;
  aspect-ratio: 4/3;
  overflow: hidden;
  background: var(--paper);
  cursor: pointer;
}
.gallery-item img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.6s var(--ease-out);
}
.gallery-item:hover img { transform: scale(1.05); }
.gallery-item .overlay {
  position: absolute; inset: 0;
  background: rgba(26,26,24,0);
  display: flex; align-items: flex-end;
  padding: 1rem;
  transition: background 0.3s;
}
.gallery-item:hover .overlay { background: rgba(26,26,24,0.5); }
.gallery-item .caption {
  color: white; font-size: 0.8rem;
  opacity: 0; transform: translateY(4px);
  transition: opacity 0.3s, transform 0.3s;
}
.gallery-item:hover .caption { opacity: 1; transform: translateY(0); }

/* ── Blog Page ── */
.page-header {
  padding: clamp(4rem, 8vw, 7rem) 0 3rem;
  border-bottom: 1px solid var(--border);
}
.page-header .label { margin-bottom: 1rem; }
.page-header h1 { margin-bottom: 1rem; }
.page-header .lead { max-width: 52ch; }

.filter-bar {
  padding: 2rem 0;
  display: flex; gap: 0.5rem; flex-wrap: wrap;
  align-items: center;
  border-bottom: 1px solid var(--border);
}
.filter-bar .label { margin-right: 0.5rem; }

#posts-list { padding: 3rem 0; }
.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2rem;
}
.post-card-grid {
  border: 1px solid var(--border);
  padding: 2rem;
  transition: border-color 0.2s, transform 0.3s var(--ease-out);
  background: var(--paper);
}
.post-card-grid:hover {
  border-color: var(--ink-light);
  transform: translateY(-3px);
}
.post-card-grid .date { font-size: 0.75rem; color: var(--ink-faint); margin-bottom: 0.75rem; }
.post-card-grid h3 { font-size: 1.15rem; margin-bottom: 0.75rem; line-height: 1.35; }
.post-card-grid .excerpt { font-size: 0.88rem; margin-bottom: 1.25rem; }
.post-card-grid .read-more {
  font-size: 0.75rem; font-weight: 600; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--ink);
  display: inline-flex; align-items: center; gap: 0.4rem;
}
.post-card-grid .read-more::after { content: '→'; transition: transform 0.2s; }
.post-card-grid:hover .read-more::after { transform: translateX(4px); }

/* ── Blog Post Single ── */
.post-hero {
  padding: clamp(4rem, 8vw, 7rem) 0 3rem;
  border-bottom: 1px solid var(--border);
}
.post-meta {
  display: flex; gap: 1.5rem; flex-wrap: wrap; align-items: center;
  margin-bottom: 2rem;
}
.post-meta span { font-size: 0.78rem; color: var(--ink-faint); }
.post-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  line-height: 1.1;
  max-width: 18ch;
  margin-bottom: 1.5rem;
}
.post-subtitle { font-size: 1.1rem; color: var(--ink-light); max-width: 52ch; margin-bottom: 0; }

.post-body { padding: 4rem 0; }
.post-content {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 var(--gap);
}
.post-content h2 {
  font-size: clamp(1.4rem, 2.5vw, 1.9rem);
  margin: 3rem 0 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}
.post-content h3 { font-size: 1.25rem; margin: 2rem 0 0.75rem; }
.post-content p { font-size: 1rem; line-height: 1.85; color: var(--ink-light); margin-bottom: 1.5em; }
.post-content ul, .post-content ol {
  margin: 0 0 1.5em 1.5em; color: var(--ink-light);
}
.post-content li { margin-bottom: 0.4em; line-height: 1.7; }
.post-content blockquote {
  border-left: 2px solid var(--ink);
  padding: 0.5rem 0 0.5rem 2rem;
  margin: 2rem 0;
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 1.2rem;
  color: var(--ink);
}
.post-content code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--paper-warm);
  padding: 0.15em 0.4em;
  border: 1px solid var(--border);
  border-radius: 2px;
}
.post-content pre {
  background: var(--ink);
  color: #e8e6df;
  padding: 2rem;
  overflow-x: auto;
  margin: 2rem 0;
  position: relative;
}
.post-content pre code {
  background: none; border: none;
  padding: 0; font-size: 0.85rem;
  color: inherit;
}
.post-content .math-block {
  overflow-x: auto;
  padding: 1.5rem;
  background: var(--paper-warm);
  border: 1px solid var(--border);
  margin: 2rem 0;
  text-align: center;
}
.post-content figure {
  margin: 2.5rem 0;
}
.post-content figure img {
  width: 100%; border: 1px solid var(--border);
}
.post-content figcaption {
  margin-top: 0.75rem;
  font-size: 0.82rem;
  color: var(--ink-faint);
  text-align: center;
  font-style: italic;
}
.post-content .chart-container {
  margin: 2.5rem 0;
  border: 1px solid var(--border);
  padding: 1.5rem;
  background: var(--paper-warm);
}

/* ── Calendar ── */
.calendar-wrapper {
  padding: 3rem 0;
}
.cal-header {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 2rem;
}
.cal-header h2 { font-size: 1.5rem; }
.cal-nav {
  display: flex; gap: 0.5rem;
}
.cal-nav button {
  width: 36px; height: 36px;
  border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.9rem; color: var(--ink-light);
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}
.cal-nav button:hover { background: var(--ink); color: var(--paper); border-color: var(--ink); }

.cal-grid {
  display: grid; grid-template-columns: repeat(7, 1fr);
  gap: 1px; background: var(--border);
  border: 1px solid var(--border);
}
.cal-day-label {
  background: var(--paper-warm);
  padding: 0.75rem 0;
  text-align: center;
  font-size: 0.7rem; font-weight: 600;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--ink-faint);
}
.cal-day {
  background: var(--paper);
  min-height: 80px;
  padding: 0.75rem;
  cursor: default;
  transition: background 0.2s;
  position: relative;
}
.cal-day.has-post {
  cursor: pointer;
  background: var(--paper-warm);
}
.cal-day.has-post:hover { background: var(--highlight); }
.cal-day.today .day-num {
  background: var(--ink);
  color: var(--paper);
  width: 26px; height: 26px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  font-weight: 600;
}
.cal-day.other-month { opacity: 0.3; }
.cal-day .day-num {
  font-size: 0.82rem; font-weight: 500;
  color: var(--ink-light); margin-bottom: 0.4rem;
  display: inline-block;
}
.cal-day .post-dot {
  display: block; margin-top: 0.25rem;
  font-size: 0.7rem; color: var(--accent);
  font-weight: 600; line-height: 1.3;
  overflow: hidden;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical;
}

.cal-modal {
  position: fixed; inset: 0;
  background: rgba(26,26,24,0.6);
  display: flex; align-items: center; justify-content: center;
  z-index: 500;
  padding: 2rem;
  opacity: 0; pointer-events: none;
  transition: opacity 0.3s;
}
.cal-modal.open { opacity: 1; pointer-events: all; }
.cal-modal-inner {
  background: var(--paper);
  max-width: 520px; width: 100%;
  padding: 3rem;
  max-height: 80vh;
  overflow-y: auto;
  transform: translateY(8px);
  transition: transform 0.3s var(--ease-out);
}
.cal-modal.open .cal-modal-inner { transform: translateY(0); }
.cal-modal-close {
  position: absolute; top: 1.5rem; right: 1.5rem;
  font-size: 1.2rem; color: var(--ink-light);
  width: 36px; height: 36px;
  display: flex; align-items: center; justify-content: center;
  border: 1px solid var(--border);
  transition: background 0.2s;
}
.cal-modal-close:hover { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.cal-modal-inner .date { font-size: 0.75rem; color: var(--ink-faint); margin-bottom: 1rem; }
.cal-modal-inner h3 { margin-bottom: 0.75rem; }
.cal-modal-inner p { font-size: 0.9rem; }
.cal-modal-inner .btn { margin-top: 1.5rem; }

/* ── Gallery Page ── */
.gallery-full-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
  padding: 3rem 0;
}
.gallery-card {
  border: 1px solid var(--border);
  overflow: hidden;
  cursor: pointer;
  transition: transform 0.3s var(--ease-out), box-shadow 0.3s;
}
.gallery-card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(26,26,24,0.08); }
.gallery-card img { width: 100%; aspect-ratio: 4/3; object-fit: cover; transition: transform 0.6s var(--ease-out); }
.gallery-card:hover img { transform: scale(1.04); }
.gallery-card-info { padding: 1rem 1.25rem; }
.gallery-card-info .caption-text { font-size: 0.88rem; color: var(--ink); margin-bottom: 0.3rem; }
.gallery-card-info .date-text { font-size: 0.75rem; color: var(--ink-faint); margin: 0; }

.lightbox {
  position: fixed; inset: 0;
  background: rgba(26,26,24,0.92);
  display: flex; align-items: center; justify-content: center;
  z-index: 600; padding: 2rem;
  opacity: 0; pointer-events: none;
  transition: opacity 0.3s;
}
.lightbox.open { opacity: 1; pointer-events: all; }
.lightbox img {
  max-width: min(90vw, 900px);
  max-height: 80vh;
  object-fit: contain;
  transform: scale(0.96);
  transition: transform 0.4s var(--ease-out);
}
.lightbox.open img { transform: scale(1); }
.lightbox-close {
  position: absolute; top: 1.5rem; right: 1.5rem;
  color: rgba(255,255,255,0.7); font-size: 1.5rem;
  width: 40px; height: 40px;
  display: flex; align-items: center; justify-content: center;
  border: 1px solid rgba(255,255,255,0.2);
  transition: color 0.2s, border-color 0.2s;
}
.lightbox-close:hover { color: white; border-color: white; }
.lightbox-caption {
  position: absolute; bottom: 2rem;
  color: rgba(255,255,255,0.7);
  font-size: 0.85rem; text-align: center;
}

/* Upload Form */
.upload-form {
  border: 1px solid var(--border);
  padding: 2.5rem;
  background: var(--paper-warm);
  margin-bottom: 3rem;
}
.upload-form h3 { margin-bottom: 1.5rem; font-size: 1.1rem; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.form-group { display: flex; flex-direction: column; gap: 0.5rem; margin-bottom: 1rem; }
.form-group label { font-size: 0.75rem; font-weight: 600; letter-spacing: 0.06em; text-transform: uppercase; color: var(--ink-faint); }
.form-group input, .form-group textarea, .form-group select {
  font-family: var(--font-sans);
  font-size: 0.92rem;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  background: var(--paper);
  color: var(--ink);
  transition: border-color 0.2s;
  outline: none;
  -webkit-appearance: none;
}
.form-group input:focus, .form-group textarea:focus, .form-group select:focus {
  border-color: var(--ink);
}
.form-group textarea { resize: vertical; min-height: 120px; }

/* ── Research Notes ── */
.notes-list { padding: 3rem 0; }
.note-card {
  border-left: 2px solid var(--border);
  padding: 0 0 2.5rem 2rem;
  position: relative;
  transition: border-color 0.2s;
}
.note-card:hover { border-color: var(--ink); }
.note-card::before {
  content: '';
  position: absolute; left: -5px; top: 0;
  width: 8px; height: 8px; background: var(--border);
  border-radius: 50%;
  transition: background 0.2s;
}
.note-card:hover::before { background: var(--ink); }
.note-card .timestamp { font-size: 0.75rem; color: var(--ink-faint); margin-bottom: 0.75rem; }
.note-card h3 { font-size: 1.2rem; margin-bottom: 0.75rem; }
.note-card .content { font-size: 0.92rem; color: var(--ink-light); }
.note-card .note-image { margin-top: 1rem; border: 1px solid var(--border); max-width: 400px; }

/* ── About Page ── */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 5rem;
  padding: 4rem 0;
}
.about-sidebar { position: sticky; top: 100px; align-self: start; }
.about-portrait {
  aspect-ratio: 3/4;
  background: var(--paper-warm);
  border: 1px solid var(--border);
  margin-bottom: 2rem;
  overflow: hidden;
}
.about-portrait img { width: 100%; height: 100%; object-fit: cover; }
.about-portrait-placeholder {
  width: 100%; height: 100%;
  display: flex; align-items: center; justify-content: center;
  color: var(--ink-faint); font-size: 3rem;
}
.social-links { display: flex; flex-direction: column; gap: 0.5rem; }
.social-link {
  display: flex; align-items: center; gap: 0.75rem;
  font-size: 0.85rem; color: var(--ink-light);
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--border);
  transition: color 0.2s;
}
.social-link:hover { color: var(--ink); }
.social-link svg { width: 16px; height: 16px; flex-shrink: 0; }

.about-content h2 { margin-bottom: 1.5rem; }
.about-content h3 { font-size: 1rem; letter-spacing: 0.06em; text-transform: uppercase; font-family: var(--font-sans); font-weight: 600; color: var(--ink-faint); margin: 3rem 0 1rem; }
.research-interests { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 1rem; }
.interest-pill {
  padding: 0.4em 1em;
  border: 1px solid var(--border);
  font-size: 0.82rem; color: var(--ink-light);
  background: var(--paper-warm);
}

.publications-list { display: flex; flex-direction: column; gap: 1.5rem; }
.pub-item { padding-bottom: 1.5rem; border-bottom: 1px solid var(--border); }
.pub-item:last-child { border-bottom: none; }
.pub-title { font-family: var(--font-serif); font-size: 1rem; margin-bottom: 0.4rem; }
.pub-authors { font-size: 0.82rem; color: var(--ink-faint); margin-bottom: 0.3rem; }
.pub-journal { font-size: 0.82rem; color: var(--ink-light); font-style: italic; margin: 0; }
.pub-links { margin-top: 0.5rem; display: flex; gap: 0.75rem; }
.pub-link {
  font-size: 0.72rem; font-weight: 600; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--ink-faint); border-bottom: 1px solid var(--border);
  transition: color 0.2s, border-color 0.2s;
}
.pub-link:hover { color: var(--ink); border-color: var(--ink); }

/* ── Contact Page ── */
.contact-grid {
  display: grid; grid-template-columns: 1fr 2fr; gap: 5rem;
  padding: 4rem 0;
}
.contact-sidebar h3 { font-size: 1rem; margin-bottom: 1rem; }
.contact-sidebar .email-link {
  font-family: var(--font-mono); font-size: 0.88rem;
  color: var(--ink); border-bottom: 1px solid var(--ink);
  display: inline-block; margin-bottom: 2rem;
  transition: opacity 0.2s;
}
.contact-sidebar .email-link:hover { opacity: 0.6; }
.contact-info-item { padding: 1rem 0; border-bottom: 1px solid var(--border); }
.contact-info-item .info-label { font-size: 0.72rem; font-weight: 600; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-faint); margin-bottom: 0.3rem; }
.contact-info-item p { font-size: 0.88rem; margin: 0; }

.contact-form-wrapper h2 { margin-bottom: 2rem; }
.contact-form .form-group { margin-bottom: 1.5rem; }
.form-success {
  padding: 1.5rem; background: var(--paper-warm); border: 1px solid var(--border);
  font-size: 0.9rem; color: var(--ink-light); display: none;
}
.form-success.show { display: block; }

/* ── Footer ── */
footer#main-footer {
  border-top: 1px solid var(--border);
  padding: 3rem 0;
  background: var(--paper-warm);
}
.footer-inner {
  display: grid; grid-template-columns: 1fr 1fr 1fr;
  gap: 3rem;
  padding-bottom: 2.5rem;
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--border);
}
.footer-brand .brand-name {
  font-family: var(--font-serif); font-size: 1.1rem; font-weight: 500;
  margin-bottom: 0.75rem;
}
.footer-brand p { font-size: 0.82rem; color: var(--ink-faint); margin: 0; }
.footer-col h4 { font-size: 0.72rem; font-weight: 600; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-faint); margin-bottom: 1rem; font-family: var(--font-sans); }
.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: 0.5rem; }
.footer-col ul a { font-size: 0.85rem; color: var(--ink-light); transition: color 0.2s; }
.footer-col ul a:hover { color: var(--ink); }
.footer-bottom { display: flex; justify-content: space-between; align-items: center; }
.footer-bottom p { font-size: 0.75rem; color: var(--ink-faint); margin: 0; }

/* ── Scroll reveal ── */
.reveal { opacity: 0; transform: translateY(20px); transition: opacity 0.8s var(--ease-out), transform 0.8s var(--ease-out); }
.reveal.visible { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }

/* ── Responsive ── */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; gap: 3rem; }
  .hero-visual { order: -1; }
  .about-grid, .contact-grid { grid-template-columns: 1fr; gap: 3rem; }
  .about-sidebar { position: static; }
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .form-row { grid-template-columns: 1fr; }
}
@media (max-width: 680px) {
  .nav-links { display: none; }
  .nav-hamburger { display: flex; }
  .footer-inner { grid-template-columns: 1fr; }
  .posts-grid { grid-template-columns: 1fr; }
  .cal-grid { gap: 0; }
  .cal-day { min-height: 56px; padding: 0.4rem; }
  .cal-day .post-dot { display: none; }
}