/* ===== Custom Properties ===== */
:root {
  --color-bg: #f0ebe0;
  --color-bg-alt: #e8e2d5;
  --color-paper: #f5f1e8;
  --color-text: #1a1a2e;
  --color-text-muted: #5a5870;
  --color-accent: #2c3e6b;
  --color-accent-hover: #1e2d52;
  --color-ink: #1a1a2e;
  --color-border: rgba(26,26,46,0.13);
  --color-card: rgba(255,255,255,0.55);
  --color-card-border: rgba(26,26,46,0.10);
  --color-grid: rgba(26,26,46,0.065);
  --color-stamp: rgba(26,26,46,0.18);
  --color-error: #b91c1c;
  --color-success: #15803d;
  --shadow-card: 0 1px 3px rgba(26,26,46,0.07), 0 4px 16px rgba(26,26,46,0.05);
  --shadow-card-hover: 0 4px 24px rgba(26,26,46,0.12);
  --radius: 0.75rem;
  --radius-sm: 0.5rem;
  --nav-h: 4rem;
  --container: 72rem;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1a1712;
    --color-bg-alt: #221e18;
    --color-paper: #1f1c16;
    --color-text: #f0ebe0;
    --color-text-muted: #a09880;
    --color-accent: #c8b98a;
    --color-accent-hover: #d4c89a;
    --color-ink: #f0ebe0;
    --color-border: rgba(240,235,224,0.10);
    --color-card: rgba(255,255,255,0.04);
    --color-card-border: rgba(240,235,224,0.09);
    --color-grid: rgba(240,235,224,0.05);
    --color-stamp: rgba(240,235,224,0.20);
    --color-error: #f87171;
    --color-success: #4ade80;
    --shadow-card: 0 1px 3px rgba(0,0,0,0.3), 0 4px 16px rgba(0,0,0,0.2);
    --shadow-card-hover: 0 4px 24px rgba(0,0,0,0.4);
  }
}

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

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

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  /* Graph-paper grid across entire page */
  background-image:
    linear-gradient(var(--color-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-grid) 1px, transparent 1px);
  background-size: 38px 38px;
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
  overflow-x: hidden;
}

ul[role="list"] { list-style: none; }
img, svg { display: block; }
a { color: inherit; text-decoration: none; }
button { cursor: pointer; font-family: inherit; font-size: inherit; border: none; background: none; }

.section { position: relative; }

/* ===== Skip Link ===== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  z-index: 9999;
  padding: 0.5rem 1rem;
  background: var(--color-accent);
  color: var(--color-bg);
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.875rem;
  transition: top 0.15s ease;
}

.skip-link:focus { top: 1rem; outline: 2px solid var(--color-bg); outline-offset: 2px; }

/* ===== Focus States ===== */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: 1.5rem;
}

.section { padding-block: 5rem; }

section[id] { scroll-margin-top: var(--nav-h); }

/* ===== Typography ===== */
.section-title {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  text-wrap: balance;
  margin-bottom: 3rem;
}

/* ===== Header / Nav ===== */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  background-color: color-mix(in srgb, var(--color-bg) 88%, transparent);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.nav-logo {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-accent);
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
  touch-action: manipulation;
  transition: opacity 0.15s ease;
}

.nav-logo:hover { opacity: 0.75; }

.nav-links { display: flex; gap: 0.125rem; list-style: none; }

.nav-link {
  display: block;
  padding: 0.5rem 0.875rem;
  border-radius: var(--radius-sm);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-muted);
  touch-action: manipulation;
  transition: color 0.15s ease, background-color 0.15s ease;
}

.nav-link:hover {
  color: var(--color-text);
  background-color: var(--color-border);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 0.5rem;
  border-radius: var(--radius-sm);
  touch-action: manipulation;
  transition: background-color 0.15s ease;
}

.nav-toggle:hover { background-color: var(--color-border); }

.bar {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 1px;
  transform-origin: center;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-toggle[aria-expanded="true"] .bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .bar:nth-child(2) { opacity: 0; transform: scaleX(0); }
.nav-toggle[aria-expanded="true"] .bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9375rem;
  line-height: 1;
  white-space: nowrap;
  touch-action: manipulation;
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease, transform 0.15s ease, opacity 0.15s ease;
}

.btn:active { transform: scale(0.97); }

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

.btn-secondary {
  background-color: transparent;
  color: var(--color-text);
  border: 1.5px solid var(--color-border);
}
.btn-secondary:hover { background-color: var(--color-border); }

.btn-outline {
  background-color: transparent;
  color: var(--color-accent);
  border: 1.5px solid var(--color-accent);
}
.btn-outline:hover { background-color: var(--color-accent); color: var(--color-bg); }

/* ===== Icon Link ===== */
.icon-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  touch-action: manipulation;
  transition: color 0.15s ease, background-color 0.15s ease;
}

.icon-link:hover { color: var(--color-text); background-color: var(--color-border); }

/* ===== Hero ===== */
.hero {
  position: relative;
  min-height: calc(100svh - var(--nav-h));
  display: flex;
  align-items: center;
  overflow: hidden;
  /* Stronger grid accent on hero */
  background-image:
    linear-gradient(rgba(26,26,46,0.09) 1px, transparent 1px),
    linear-gradient(90deg, rgba(26,26,46,0.09) 1px, transparent 1px);
  background-size: 38px 38px;
}

@media (prefers-color-scheme: dark) {
  .hero {
    background-image:
      linear-gradient(rgba(240,235,224,0.07) 1px, transparent 1px),
      linear-gradient(90deg, rgba(240,235,224,0.07) 1px, transparent 1px);
  }
}

.hero-content {
  position: relative;
  z-index: 1;
  padding-block: 5rem;
  padding-right: 5rem; /* room for vertical social links */
}

/* ===== Hero: Postmark Stamps ===== */
.postmark {
  position: absolute;
  color: var(--color-stamp);
  pointer-events: none;
  z-index: 0;
}

.postmark-tl {
  top: 2rem;
  left: 2rem;
  opacity: 0.6;
}

.postmark-br {
  bottom: 2.5rem;
  right: 5rem;
  opacity: 0.45;
}

/* ===== Hero: Vertical Social Nav ===== */
.hero-social-vert {
  position: absolute;
  right: 0;
  top: 0;
  bottom: 0;
  width: 3.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  border-left: 1px solid var(--color-border);
  z-index: 2;
}

.vert-link {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  color: var(--color-text-muted);
  touch-action: manipulation;
  padding: 0.5rem 0.25rem;
  border-radius: var(--radius-sm);
  transition: color 0.15s ease, background-color 0.15s ease;
}

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

.vert-divider {
  width: 1px;
  height: 1.5rem;
  background-color: var(--color-border);
  flex-shrink: 0;
}

/* ===== Hero: Content ===== */
.hero-greeting {
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--color-text-muted);
  letter-spacing: 0.01em;
  margin-bottom: 0.75rem;
}

.hero-name-row {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.hero-name {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: clamp(3rem, 10vw, 6rem);
  font-weight: 900;
  line-height: 1.0;
  letter-spacing: -0.03em;
  text-wrap: balance;
  color: var(--color-ink);
}

.name-asterisk {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 0.45em;
  font-weight: 700;
  color: var(--color-accent);
  vertical-align: super;
  margin-left: 0.1em;
}

.hero-waves {
  color: var(--color-accent);
  opacity: 0.55;
  align-self: center;
  flex-shrink: 0;
  margin-top: 0.25rem;
}

.hero-title {
  font-size: clamp(1rem, 2.5vw, 1.375rem);
  color: var(--color-text-muted);
  font-weight: 500;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  margin-bottom: 1.25rem;
}

.hero-tagline {
  font-size: 1.0625rem;
  color: var(--color-text-muted);
  max-width: 44ch;
  text-wrap: pretty;
  margin-bottom: 2.5rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.875rem;
  margin-bottom: 3rem;
}

.hero-footnote {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  opacity: 0.75;
  max-width: 56ch;
  line-height: 1.7;
  border-top: 1px solid var(--color-border);
  padding-top: 1rem;
}

/* ===== About ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 3rem;
  align-items: center;
}

@media (min-width: 768px) {
  .about-grid { grid-template-columns: 1fr auto; gap: 5rem; }
}

.about-text p {
  color: var(--color-text-muted);
  font-size: 1.0625rem;
  max-width: 55ch;
  margin-bottom: 1rem;
}

.about-text .btn { margin-top: 0.5rem; }

.about-stats {
  display: flex;
  flex-direction: row;
  gap: 2rem;
  flex-shrink: 0;
}

@media (min-width: 768px) {
  .about-stats { flex-direction: column; gap: 1.75rem; }
}

.stat { display: flex; flex-direction: column; }

.stat-number {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
  line-height: 1;
}

.stat-label { font-size: 0.8125rem; color: var(--color-text-muted); margin-top: 0.3rem; }

/* ===== Cards (Skills & Projects) ===== */
.skill-card,
.project-card {
  background-color: var(--color-card);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  box-shadow: var(--shadow-card);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.skill-card:hover,
.project-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-card-hover);
}

/* ===== Skills ===== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.25rem;
}

.skill-card { padding: 1.75rem; }

.skill-category {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 1rem;
}

.skill-list { display: flex; flex-direction: column; gap: 0.625rem; list-style: none; }

.skill-list li {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  padding-left: 1.125rem;
  position: relative;
}

.skill-list li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-size: 0.75rem;
  top: 0.15rem;
}

/* ===== Projects ===== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.25rem;
}

.project-card {
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.project-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
}

.project-title {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1.0625rem;
  font-weight: 700;
}

.project-links { display: flex; gap: 0.375rem; flex-shrink: 0; }

.project-desc {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  flex: 1;
  overflow: hidden;
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 4;
}

.tech-tags { display: flex; flex-wrap: wrap; gap: 0.5rem; list-style: none; margin-top: auto; }

.tag {
  font-size: 0.8125rem;
  font-weight: 500;
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  background-color: color-mix(in srgb, var(--color-accent) 10%, transparent);
  color: var(--color-accent);
  border: 1px solid color-mix(in srgb, var(--color-accent) 20%, transparent);
}

/* ===== Contact ===== */
.contact-subtitle {
  color: var(--color-text-muted);
  font-size: 1.0625rem;
  max-width: 50ch;
  margin-bottom: 2.5rem;
  text-wrap: pretty;
}

.contact-form {
  max-width: 640px;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.form-row { display: grid; grid-template-columns: 1fr; gap: 1.25rem; }

@media (min-width: 540px) { .form-row { grid-template-columns: 1fr 1fr; } }

.form-group { display: flex; flex-direction: column; gap: 0.375rem; }

.form-label { font-size: 0.9375rem; font-weight: 500; }

.form-input {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  background-color: color-mix(in srgb, var(--color-bg) 70%, transparent);
  color: var(--color-text);
  font-family: inherit;
  font-size: 1rem;
  line-height: 1.5;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.form-input::placeholder { color: var(--color-text-muted); opacity: 0.7; }

.form-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-accent) 15%, transparent);
}

.form-input.has-error { border-color: var(--color-error); }
.form-input.has-error:focus {
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-error) 15%, transparent);
}

.form-textarea { min-height: 9rem; resize: vertical; }

.form-error { font-size: 0.8125rem; color: var(--color-error); min-height: 1.1em; }

.btn-submit { align-self: flex-start; min-width: 10rem; }
.btn-submit:disabled { opacity: 0.65; cursor: not-allowed; transform: none; }

.btn-spinner {
  flex-shrink: 0;
  animation: spin 0.7s linear infinite;
  transform-origin: center;
}

@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }

@media (prefers-reduced-motion: reduce) { .btn-spinner { animation: none; } }

.form-success {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-success);
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  background-color: color-mix(in srgb, var(--color-success) 8%, transparent);
  border: 1px solid color-mix(in srgb, var(--color-success) 20%, transparent);
}

/* ===== Featured Project ===== */
.project-badge {
  display: inline-block;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background-color: color-mix(in srgb, var(--color-accent) 12%, transparent);
  color: var(--color-accent);
  border: 1px solid color-mix(in srgb, var(--color-accent) 22%, transparent);
  margin-bottom: 0.5rem;
}

.project-badge-research {
  background-color: color-mix(in srgb, #b45309 12%, transparent);
  color: #92400e;
  border-color: color-mix(in srgb, #b45309 22%, transparent);
}

@media (prefers-color-scheme: dark) {
  .project-badge-research { color: #fbbf24; background-color: color-mix(in srgb, #fbbf24 10%, transparent); border-color: color-mix(in srgb, #fbbf24 20%, transparent); }
}

.project-featured {
  grid-column: 1 / -1;
}

.project-role {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  margin-top: 0.2rem;
}

.card-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 0.75rem;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-accent);
  touch-action: manipulation;
  transition: gap 0.2s ease, opacity 0.2s ease;
}

.card-cta:hover { gap: 0.875rem; opacity: 0.8; }

.cta-arrow {
  flex-shrink: 0;
  transition: transform 0.2s ease;
}

.card-cta:hover .cta-arrow { transform: translateX(5px); }

@media (prefers-reduced-motion: reduce) {
  .cta-arrow { transition: none; }
  .card-cta { transition: none; }
}

/* ===== Skills Cloud ===== */
.skills-cloud {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.skill-group { display: flex; flex-direction: column; gap: 0.75rem; }

.skill-group-label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
}

/* ===== Experience ===== */
.experience-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 3rem;
}

@media (min-width: 768px) {
  .experience-grid { grid-template-columns: 1fr 1fr; gap: 4rem; }
}

.exp-col { display: flex; flex-direction: column; gap: 0; }

.exp-col-title {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 1.5rem;
}

.exp-entry {
  padding-block: 1.25rem;
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.exp-entry:last-child { border-bottom: 1px solid var(--color-border); }

.exp-org {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-text);
}

.exp-role {
  font-size: 0.875rem;
  color: var(--color-accent);
  font-weight: 500;
}

.exp-date {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
}

.exp-note {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  margin-top: 0.25rem;
  opacity: 0.8;
}

/* ===== Footer ===== */
.footer {
  border-top: 1px solid var(--color-border);
  padding-block: 2rem;
  padding-bottom: calc(2rem + env(safe-area-inset-bottom));
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-copy { font-size: 0.875rem; color: var(--color-text-muted); }
.footer-social { display: flex; gap: 0.375rem; }

/* ===== Scroll Fade-up ===== */
.fade-up {
  opacity: 0;
  transform: translateY(1.25rem);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.fade-up.visible { opacity: 1; transform: translateY(0); }

@media (prefers-reduced-motion: reduce) {
  .fade-up { opacity: 1; transform: none; transition: none; }
}

/* ===== Mobile Nav ===== */
@media (max-width: 640px) {
  .nav-toggle { display: flex; }

  .nav-links {
    position: fixed;
    inset: var(--nav-h) 0 0 0;
    flex-direction: column;
    background-color: var(--color-bg);
    background-image:
      linear-gradient(var(--color-grid) 1px, transparent 1px),
      linear-gradient(90deg, var(--color-grid) 1px, transparent 1px);
    background-size: 38px 38px;
    padding: 1.5rem;
    gap: 0.25rem;
    z-index: 99;
    border-top: 1px solid var(--color-border);
    overflow-y: auto;
    overscroll-behavior: contain;
    transform: translateX(100%);
    transition: transform 0.25s ease;
  }

  .nav-links.open { transform: translateX(0); }
  .nav-link { font-size: 1.125rem; padding: 0.875rem 1rem; }

  .hero-social-vert { display: none; }
  .hero-content { padding-right: 1.5rem; }
  .postmark-br { right: 1rem; }
}

/* ===== Reduced Motion: disable card transforms ===== */
@media (prefers-reduced-motion: reduce) {
  .skill-card, .project-card, .btn { transition: none; }
  .skill-card:hover, .project-card:hover { transform: none; }
}