:root {
  --transition-theme: background 0.35s ease, color 0.35s ease, border-color 0.35s ease, box-shadow 0.35s ease;
}

[data-theme="dark"] {
  --bg: #1a1917;
  --bg-alt: #21201d;
  --surface: #2a2926;
  --text: #e2dfd8;
  --text-muted: #a09a90;
  --accent: #5a9e8f;
  --accent-hover: #6db3a3;
  --border: #373530;
  --tag-bg: #312f2b;
  --nav-bg: rgba(26,25,23,0.88);
  --shadow: 0 1px 3px rgba(0,0,0,0.2), 0 4px 12px rgba(0,0,0,0.15);
  --shadow-hover: 0 2px 8px rgba(0,0,0,0.3), 0 8px 24px rgba(0,0,0,0.2);
  --placeholder-bg: #312f2b;
  --toggle-bg: #312f2b;
  --toggle-knob: #e2dfd8;
}

[data-theme="light"] {
  --bg: #f2f0ec;
  --bg-alt: #e8e6e1;
  --surface: #ffffff;
  --text: #262420;
  --text-muted: #555048;
  --accent: #3d7a6d;
  --accent-hover: #2e5f54;
  --border: #d2cfc8;
  --tag-bg: #e3e0da;
  --nav-bg: rgba(242,240,236,0.88);
  --shadow: 0 1px 3px rgba(38,36,32,0.06), 0 4px 12px rgba(38,36,32,0.04);
  --shadow-hover: 0 2px 8px rgba(38,36,32,0.1), 0 8px 24px rgba(38,36,32,0.06);
  --placeholder-bg: #e3e0da;
  --toggle-bg: #d2cfc8;
  --toggle-knob: #262420;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }
html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Karla', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  transition: var(--transition-theme);
}

/* ===== NAV ===== */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: var(--nav-bg);
  backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  transition: var(--transition-theme), box-shadow 0.3s;
}
nav.scrolled { box-shadow: 0 1px 8px rgba(0,0,0,0.12); }
.nav-inner {
  max-width: 1000px; margin: 0 auto; padding: 0 2rem;
  height: 56px; display: flex; align-items: center; justify-content: space-between;
}
.nav-name {
  font-family: 'Libre Baskerville', Georgia, serif;
  font-size: 1.1rem; color: var(--text); text-decoration: none;
  transition: var(--transition-theme);
}
.nav-right { display: flex; align-items: center; gap: 1.5rem; }
.nav-links { display: flex; gap: 1.5rem; }
.nav-links a {
  font-size: 0.78rem; font-weight: 500; color: var(--text-muted);
  text-decoration: none; letter-spacing: 0.04em; text-transform: uppercase;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--accent); }

/* ===== THEME TOGGLE ===== */
.theme-toggle {
  position: relative; width: 44px; height: 24px;
  background: var(--toggle-bg); border-radius: 12px;
  cursor: pointer; border: none; padding: 0;
  transition: background 0.3s; flex-shrink: 0;
}
.theme-toggle .knob {
  position: absolute; top: 3px; left: 3px;
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--toggle-knob);
  transition: transform 0.3s ease, background 0.3s;
  display: flex; align-items: center; justify-content: center;
}
[data-theme="light"] .theme-toggle .knob { transform: translateX(20px); }
.theme-toggle .icon { font-size: 10px; line-height: 1; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }
[data-theme="light"] .icon-sun { display: block; }
[data-theme="light"] .icon-moon { display: none; }

/* ===== SECTIONS ===== */
section { padding: 5rem 2rem; transition: var(--transition-theme); }
.container { max-width: 1000px; margin: 0 auto; }
.section-label {
  font-family: 'Karla', sans-serif;
  font-size: 0.72rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 0.12em; color: var(--accent); margin-bottom: 0.75rem;
}
.section-title {
  font-family: 'Libre Baskerville', Georgia, serif; font-size: 2rem;
  font-weight: 400; line-height: 1.25; margin-bottom: 2.5rem; color: var(--text);
  transition: var(--transition-theme);
}

/* ===== HERO ===== */
#hero { padding-top: 10rem; padding-bottom: 5rem; }
.hero-layout { display: flex; align-items: flex-start; gap: 3rem; }
.hero-text { flex: 1; }
.hero-photo {
  width: 180px; height: 180px; border-radius: 50%;
  background: var(--placeholder-bg); border: 3px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0; overflow: hidden; transition: var(--transition-theme);
}
.hero-photo img {
  width: 100%; height: 100%; object-fit: cover;
  transition: transform 0.3s ease;
}
.hero-photo:hover img { transform: scale(1.06); }
.hero-eyebrow {
  font-size: 0.82rem; font-weight: 500; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--text-muted); margin-bottom: 0.75rem;
}
.hero-name {
  font-family: 'Libre Baskerville', Georgia, serif;
  font-size: clamp(2.4rem, 5.2vw, 3.6rem);
  font-weight: 400; line-height: 1.15; margin-bottom: 1.25rem;
}
.hero-name .accent { color: var(--accent); }
.hero-sub {
  font-size: 1.02rem; color: var(--text-muted);
  max-width: 520px; line-height: 1.75; margin-bottom: 1.75rem;
}
.hero-links { display: flex; gap: 0.75rem; flex-wrap: wrap; }
.hero-links a {
  display: inline-flex; align-items: center; gap: 0.4rem;
  font-size: 0.82rem; font-weight: 500; color: var(--text);
  text-decoration: none; padding: 0.5rem 1rem;
  border: 1px solid var(--border); border-radius: 6px;
  transition: all 0.2s;
}
.hero-links a:hover {
  border-color: var(--accent); color: var(--accent);
  background: color-mix(in srgb, var(--accent) 6%, transparent);
}
.hero-links a svg { width: 15px; height: 15px; }
.hero-meta-prominent {
  margin-top: 1rem; font-size: 0.82rem; font-weight: 600;
  color: var(--accent); letter-spacing: 0.03em;
}

/* ===== ABOUT ===== */
#about { background: var(--bg-alt); }
.about-layout {
  display: flex; align-items: center; gap: 2.5rem;
}
.about-text {
  font-size: 1.02rem; color: var(--text-muted);
  max-width: 660px; line-height: 1.8; flex: 1;
}
.about-photo {
  flex-shrink: 0; width: 240px;
}
.about-photo img {
  width: 100%; height: auto; border-radius: 10px;
  border: 3px solid var(--border); display: block;
  transition: var(--transition-theme), transform 0.3s ease;
}
.about-photo img:hover {
  transform: scale(1.06);
}

/* ===== EDUCATION ===== */
#education { background: var(--bg-alt); padding-top: 0; padding-bottom: 5rem; }
.edu-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 6px; padding: 1.5rem 1.75rem; box-shadow: var(--shadow);
  max-width: 580px; transition: var(--transition-theme);
}
.edu-school {
  font-family: 'Libre Baskerville', Georgia, serif; font-size: 1.2rem;
  margin-bottom: 0.25rem;
}
.edu-detail { font-size: 0.9rem; color: var(--text-muted); }
.edu-coursework { margin-top: 0.6rem; font-size: 0.85rem; }
.edu-affiliations { margin-top: 0.75rem; font-size: 0.85rem; color: var(--text-muted); }

/* ===== EXPERIENCE ===== */
.exp-list { display: flex; flex-direction: column; gap: 1.25rem; }
.exp-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 6px; padding: 1.5rem 1.75rem; box-shadow: var(--shadow);
  transition: box-shadow 0.25s, var(--transition-theme);
}
.exp-card:hover { box-shadow: var(--shadow-hover); }
.exp-card.engineering { border-left: 3px solid var(--accent); }
.exp-header {
  display: flex; justify-content: space-between; align-items: flex-start;
  gap: 1rem; margin-bottom: 0.4rem; flex-wrap: wrap;
}
.exp-role { font-weight: 700; font-size: 1rem; }
.exp-company { color: var(--accent); font-weight: 500; font-size: 0.95rem; }
.exp-date { font-size: 0.8rem; color: var(--text-muted); white-space: nowrap; }
.exp-desc { color: var(--text-muted); font-size: 0.88rem; margin-top: 0.5rem; }
.exp-desc ul { padding-left: 1.2rem; margin-top: 0.3rem; }
.exp-desc li { margin-bottom: 0.3rem; }

/* ===== PROJECTS ===== */
#projects { background: var(--bg-alt); }
.project-list { display: flex; flex-direction: column; gap: 2.5rem; }
.project-card {
  display: grid; grid-template-columns: 1fr 1fr; gap: 0;
  align-items: stretch; background: var(--surface);
  border: 1px solid var(--border); border-radius: 6px;
  overflow: hidden; box-shadow: var(--shadow);
  transition: box-shadow 0.25s, var(--transition-theme);
}
.project-card:hover { box-shadow: var(--shadow-hover); }
.project-card:nth-child(even) .project-img { order: 2; }
.project-card:nth-child(even) .project-info { order: 1; }
.project-img {
  width: 100%; min-height: 260px; background: var(--placeholder-bg);
  display: flex; align-items: center; justify-content: center; overflow: hidden;
  transition: var(--transition-theme);
}
.project-img img {
  width: 100%; height: 100%; object-fit: cover;
  transition: transform 0.3s ease;
}
.project-img:hover img { transform: scale(1.04); }
.project-info {
  padding: 1.75rem 2rem; display: flex; flex-direction: column; justify-content: center;
}
.project-title {
  font-family: 'Libre Baskerville', Georgia, serif; font-size: 1.3rem; margin-bottom: 0.4rem;
}
.project-tags { display: flex; flex-wrap: wrap; gap: 0.35rem; margin-bottom: 0.85rem; }
.project-tags span {
  font-size: 0.7rem; font-weight: 500; background: var(--tag-bg);
  color: var(--text-muted); padding: 0.2rem 0.55rem; border-radius: 3px;
  letter-spacing: 0.02em; transition: var(--transition-theme);
}
.project-summary {
  font-size: 0.92rem; color: var(--text-muted); line-height: 1.7; margin-bottom: 1rem;
}
.project-links { display: flex; gap: 1rem; flex-wrap: wrap; }
.project-link {
  font-size: 0.82rem; font-weight: 600; color: var(--accent);
  text-decoration: none; display: inline-flex; align-items: center;
  gap: 0.3rem; transition: gap 0.2s;
}
.project-link:hover { gap: 0.5rem; }
.project-link::after { content: '\2192'; }

/* ===== SKILLS ===== */
.skills-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
  gap: 1.75rem;
}
.skill-group h3 {
  font-size: 0.75rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 0.08em; color: var(--accent); margin-bottom: 0.5rem;
}
.skill-group ul { list-style: none; display: flex; flex-direction: column; gap: 0.3rem; }
.skill-group li { font-size: 0.87rem; color: var(--text-muted); }

/* ===== INTERESTS ===== */
#interests { padding-top: 2rem; padding-bottom: 4rem; }
.interests-row {
  display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 0.5rem;
}
.interests-row span {
  font-size: 0.82rem; background: var(--tag-bg); color: var(--text-muted);
  padding: 0.35rem 0.85rem; border-radius: 20px; transition: var(--transition-theme);
}

/* ===== FOOTER ===== */
footer {
  background: var(--surface); border-top: 1px solid var(--border);
  padding: 3.5rem 2rem; text-align: center; transition: var(--transition-theme);
}
.footer-name {
  font-family: 'Libre Baskerville', Georgia, serif; font-size: 1.3rem; margin-bottom: 0.4rem;
}
.footer-tagline { font-size: 0.85rem; color: var(--text-muted); margin-bottom: 1.5rem; }
.footer-links {
  display: flex; gap: 1.5rem; justify-content: center;
  flex-wrap: wrap; margin-bottom: 1rem;
}
.footer-links a {
  font-size: 0.82rem; color: var(--text-muted); text-decoration: none;
  transition: color 0.2s;
}
.footer-links a:hover { color: var(--accent); }
.footer-copy { font-size: 0.72rem; color: var(--text-muted); opacity: 0.5; }

/* ===== LIGHTBOX ===== */
[data-lightbox] { cursor: zoom-in; }
.lightbox {
  position: fixed; inset: 0; z-index: 200;
  display: flex; align-items: center; justify-content: center;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(8px); -webkit-backdrop-filter: blur(8px);
  opacity: 0; pointer-events: none;
  transition: opacity 0.25s ease;
  cursor: zoom-out;
}
.lightbox.active {
  opacity: 1; pointer-events: auto;
}
.lightbox-close {
  position: absolute; top: 1.5rem; right: 1.5rem;
  background: none; border: none; color: #fff;
  font-size: 2rem; cursor: pointer; opacity: 0.7;
  transition: opacity 0.2s; z-index: 1;
  width: 40px; height: 40px; display: flex;
  align-items: center; justify-content: center;
}
.lightbox-close:hover { opacity: 1; }
.lightbox-close:focus-visible {
  outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px;
}
.lightbox img {
  max-width: 90vw; max-height: 85vh;
  border-radius: 8px;
  box-shadow: 0 8px 40px rgba(0,0,0,0.5);
  transform: scale(0.92);
  transition: transform 0.25s ease;
}
.lightbox.active img {
  transform: scale(1);
}

/* ===== ANIMATIONS ===== */
.fade-in {
  opacity: 0; transform: translateY(18px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* ===== RESPONSIVE ===== */
@media (max-width: 700px) {
  section { padding: 3.5rem 1.25rem; }
  .hero-layout { flex-direction: column-reverse; align-items: center; text-align: center; }
  .hero-photo { width: 140px; height: 140px; }
  .hero-links { justify-content: center; }
  .hero-sub { margin-left: auto; margin-right: auto; }
  .about-layout { flex-direction: column; text-align: center; }
  .about-photo { width: 180px; margin: 0 auto; }
  .project-card { grid-template-columns: 1fr; }
  .project-card:nth-child(even) .project-img { order: 0; }
  .project-card:nth-child(even) .project-info { order: 0; }
  .project-img { min-height: 190px; }
  .project-info { padding: 1.25rem 1.5rem; }
  .exp-header { flex-direction: column; gap: 0.2rem; }
  .nav-links { gap: 0.9rem; }
  .nav-links a { font-size: 0.76rem; }
  .skills-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 420px) {
  .nav-links { gap: 0.6rem; }
  .nav-right { gap: 0.8rem; }
}