/* ============================================================
   THEME VARIABLES  —  change these to recolor the whole site
   ============================================================ */
:root {
  --bg:        #05060b;   /* deep space background        */
  --bg-2:      #090c15;   /* slightly lighter panels      */
  --surface:   rgba(255, 255, 255, 0.035);
  --border:    rgba(255, 255, 255, 0.09);
  --text:      #e9edf6;   /* main text                    */
  --muted:     #9aa5bd;   /* secondary text               */
  --accent:    #6ea8fe;   /* primary blue                 */
  --accent-2:  #b18cff;   /* purple                       */
  --accent-3:  #57e0d0;   /* teal highlight               */
  --maxw:      1080px;
  --radius:    16px;
  --font-head: "Space Grotesk", system-ui, sans-serif;
  --font-body: "Inter", system-ui, -apple-system, sans-serif;
}

/* ============================================================
   RESET / BASE
   ============================================================ */
* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; scroll-padding-top: 84px; }

body {
  font-family: var(--font-body);
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* subtle glows layered over the background */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(60% 50% at 15% 0%, rgba(110, 168, 254, 0.10), transparent 60%),
    radial-gradient(50% 50% at 90% 20%, rgba(177, 140, 255, 0.10), transparent 60%),
    radial-gradient(70% 60% at 50% 110%, rgba(87, 224, 208, 0.06), transparent 60%);
  pointer-events: none;
}

#starfield {
  position: fixed;
  inset: 0;
  z-index: -2;
  display: block;
  transition: opacity .8s ease;
}

/* Sun — fades/rises in when light theme is active */
.sun {
  position: fixed; top: -90px; right: -70px; width: 280px; height: 280px;
  border-radius: 50%; z-index: -1; pointer-events: none;
  background: radial-gradient(circle at 50% 50%, #fff6c4 0%, #ffde7a 38%, #ffb24d 62%, rgba(255,178,77,0) 70%);
  opacity: 0; transform: scale(.4) translateY(40px);
  transition: opacity 1s ease, transform 1s ease;
}
:root[data-theme="light"] .sun { opacity: 1; transform: scale(1) translateY(0); }
:root[data-theme="light"] #starfield { opacity: 0; }

h1, h2, h3 { font-family: var(--font-head); font-weight: 700; line-height: 1.15; }

a { color: var(--accent); text-decoration: none; transition: color .2s ease; }
a:hover { color: #fff; }

section { scroll-margin-top: 84px; }

.accent {
  background: linear-gradient(120deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}

/* ============================================================
   NAV
   ============================================================ */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  transition: background .3s ease, border-color .3s ease;
  border-bottom: 1px solid transparent;
}
.nav.scrolled {
  background: rgba(6, 8, 15, 0.72);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav__inner {
  max-width: var(--maxw); margin: 0 auto;
  padding: 16px 24px;
  display: flex; align-items: center; justify-content: space-between;
}
.nav__logo {
  font-family: var(--font-head); font-weight: 700; font-size: 1.3rem;
  color: var(--text); letter-spacing: .5px;
}
.nav__logo span { color: var(--accent); }
.nav__links { display: flex; align-items: center; gap: 22px; }
.nav__links a { color: var(--muted); font-size: .95rem; font-weight: 500; position: relative; }
.nav__links a:not(.nav__cv)::after {
  content: ""; position: absolute; left: 0; bottom: -6px; height: 2px; width: 0;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transition: width .25s ease;
}
.nav__links a:not(.nav__cv):hover::after,
.nav__links a.active::after { width: 100%; }
.nav__links a:hover, .nav__links a.active { color: var(--text); }
.nav__cv {
  border: 1px solid var(--border); padding: 7px 16px; border-radius: 999px;
  color: var(--text) !important;
}
.nav__cv:hover { border-color: var(--accent); background: rgba(110,168,254,.1); }
.nav__theme {
  background: none; border: 0; cursor: pointer; font-size: 1.15rem; line-height: 1;
  padding: 4px 6px; border-radius: 50%; transition: transform .4s ease, background .2s ease;
}
.nav__theme:hover { transform: rotate(25deg) scale(1.15); background: var(--surface); }

.nav__toggle { display: none; flex-direction: column; gap: 5px; background: none; border: 0; cursor: pointer; padding: 6px; }
.nav__toggle span { width: 24px; height: 2px; background: var(--text); border-radius: 2px; transition: .3s; }

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-block; padding: 13px 26px; border-radius: 999px;
  font-weight: 600; font-size: .98rem; cursor: pointer;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease;
}
.btn--primary {
  background: linear-gradient(120deg, var(--accent), var(--accent-2));
  color: #06070d;
  box-shadow: 0 8px 30px rgba(110, 168, 254, 0.28);
}
.btn--primary:hover { transform: translateY(-3px); color: #06070d; box-shadow: 0 12px 40px rgba(110, 168, 254, 0.4); }
.btn--ghost { border: 1px solid var(--border); color: var(--text); }
.btn--ghost:hover { transform: translateY(-3px); border-color: var(--accent); color: #fff; }

/* ============================================================
   HERO
   ============================================================ */
.hero {
  min-height: 100vh;
  max-width: var(--maxw); margin: 0 auto;
  padding: 120px 24px 60px;
  display: flex; flex-direction: column; justify-content: center;
  position: relative;
}
.hero__eyebrow {
  color: var(--accent-3); font-weight: 600; letter-spacing: 1px;
  text-transform: uppercase; font-size: .82rem; margin-bottom: 18px;
}
.hero__name {
  font-size: clamp(2.8rem, 9vw, 6rem);
  letter-spacing: -1px; margin-bottom: 22px;
  background: linear-gradient(180deg, #fff 30%, #b9c4de);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero__tagline {
  font-size: clamp(1.05rem, 2.4vw, 1.4rem);
  color: var(--muted); max-width: 620px; margin-bottom: 36px;
}
.hero__cta { display: flex; gap: 16px; flex-wrap: wrap; }

.scroll-hint {
  position: absolute; bottom: 30px; left: 50%; transform: translateX(-50%);
  color: var(--muted); font-size: 1.5rem; animation: bob 1.8s ease-in-out infinite;
}
@keyframes bob { 0%,100% { transform: translate(-50%, 0); } 50% { transform: translate(-50%, 10px); } }

/* Orbit decoration */
.orbit {
  position: absolute; top: 50%; right: -60px; transform: translateY(-50%);
  width: 340px; height: 340px; pointer-events: none; opacity: .9;
}
.orbit__planet {
  position: absolute; top: 50%; left: 50%; width: 90px; height: 90px;
  transform: translate(-50%, -50%); border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, #8fb8ff, #3a5bd0 55%, #1a2a6b);
  box-shadow: 0 0 60px rgba(110, 168, 254, .5), inset -12px -12px 30px rgba(0,0,0,.5);
}
.orbit__ring {
  position: absolute; top: 50%; left: 50%; border-radius: 50%;
  border: 1px solid rgba(255,255,255,.12);
  transform: translate(-50%, -50%) rotate(0deg);
}
.orbit__ring--1 { width: 220px; height: 220px; animation: spin 14s linear infinite; }
.orbit__ring--2 { width: 320px; height: 320px; animation: spin 26s linear infinite reverse; }
.orbit__moon {
  position: absolute; top: -4px; left: 50%; width: 12px; height: 12px;
  border-radius: 50%; background: var(--accent-3); box-shadow: 0 0 16px var(--accent-3);
}
.orbit__ring--2 .orbit__moon { background: var(--accent-2); box-shadow: 0 0 16px var(--accent-2); }
@keyframes spin { to { transform: translate(-50%, -50%) rotate(360deg); } }

/* ============================================================
   SECTIONS (shared)
   ============================================================ */
.section { max-width: var(--maxw); margin: 0 auto; padding: 90px 24px; }
.section__head { display: flex; align-items: baseline; gap: 14px; margin-bottom: 22px; }
.section__num {
  font-family: var(--font-head); color: var(--accent);
  font-size: 1rem; font-weight: 600; opacity: .8;
}
.section__head h2 { font-size: clamp(1.8rem, 4vw, 2.6rem); }
.section__lead { color: var(--muted); max-width: 640px; margin-bottom: 44px; font-size: 1.05rem; }

/* ============================================================
   ABOUT
   ============================================================ */
.about { display: grid; grid-template-columns: 260px 1fr; gap: 44px; align-items: start; }
.about__photo { position: relative; }
.about__photo img,
.about__photo-fallback {
  width: 100%; aspect-ratio: 1; border-radius: 20px; object-fit: cover;
  border: 1px solid var(--border);
}
.about__photo-fallback {
  display: none; align-items: center; justify-content: center; font-size: 5rem;
  background: linear-gradient(145deg, #101728, #1a1030);
}
.about__text p { margin-bottom: 16px; color: #c9d2e6; }
.about__facts { list-style: none; display: flex; flex-wrap: wrap; gap: 12px; margin-top: 24px; }
.about__facts li {
  display: flex; align-items: center; gap: 8px;
  background: var(--surface); border: 1px solid var(--border);
  padding: 8px 16px; border-radius: 999px; font-size: .9rem; color: var(--muted);
}

/* ============================================================
   GRIDS / CARDS
   ============================================================ */
.grid { display: grid; gap: 22px; }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }

.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 30px 26px;
  transition: transform .25s ease, border-color .25s ease, background .25s ease;
}
.card:hover { transform: translateY(-6px); border-color: rgba(110,168,254,.4); background: rgba(110,168,254,.05); }
.card__icon { font-size: 2rem; margin-bottom: 14px; }
.card h3 { font-size: 1.2rem; margin-bottom: 10px; }
.card p { color: var(--muted); font-size: .96rem; }

/* Projects */
.project {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); overflow: hidden;
  display: flex; flex-direction: column;
  transition: transform .25s ease, border-color .25s ease;
}
.project:hover { transform: translateY(-6px); border-color: rgba(177,140,255,.45); }
.project__media {
  height: 150px; display: flex; align-items: center; justify-content: center;
  font-size: 3rem;
  background: linear-gradient(135deg, var(--g1, #1b2a4a), var(--g2, #4a2b6b));
  border-bottom: 1px solid var(--border);
}
.project__body { padding: 24px; display: flex; flex-direction: column; gap: 12px; flex: 1; }
.project__body h3 { font-size: 1.25rem; }
.project__body p { color: var(--muted); font-size: .96rem; flex: 1; }
.tags { display: flex; flex-wrap: wrap; gap: 8px; }
.tags span {
  font-size: .78rem; color: var(--accent-3);
  background: rgba(87,224,208,.09); border: 1px solid rgba(87,224,208,.2);
  padding: 4px 11px; border-radius: 999px;
}
.project__links { display: flex; gap: 18px; margin-top: 4px; font-weight: 600; font-size: .92rem; }

/* ============================================================
   PUBLICATIONS
   ============================================================ */
.pubs { list-style: none; counter-reset: pub; display: flex; flex-direction: column; gap: 18px; }
.pub {
  position: relative; padding: 24px 26px 24px 62px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  transition: border-color .25s ease, transform .25s ease;
}
.pub:hover { border-color: rgba(110,168,254,.4); transform: translateX(4px); }
.pub::before {
  counter-increment: pub; content: counter(pub, decimal-leading-zero);
  position: absolute; left: 22px; top: 24px;
  font-family: var(--font-head); color: var(--accent); font-weight: 600;
}
.pub__title { font-size: 1.12rem; margin-bottom: 8px; }
.pub__authors { color: #c9d2e6; font-size: .95rem; }
.pub__authors b { color: #fff; }
.pub__venue { color: var(--muted); font-size: .92rem; margin: 2px 0 12px; }
.pub__links { display: flex; gap: 10px; flex-wrap: wrap; }
.pub__links a {
  font-size: .82rem; font-weight: 600; padding: 4px 12px; border-radius: 999px;
  border: 1px solid var(--border); color: var(--muted);
}
.pub__links a:hover { border-color: var(--accent); color: #fff; }

/* ============================================================
   CONTACT / FOOTER
   ============================================================ */
.section--contact { text-align: center; }
.section--contact .section__head { justify-content: center; }
.section--contact .section__lead { margin-left: auto; margin-right: auto; }
.contact-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-bottom: 40px; }
.socials { list-style: none; display: flex; gap: 14px; justify-content: center; }
.socials a {
  display: grid; place-items: center; width: 48px; height: 48px; border-radius: 50%;
  border: 1px solid var(--border); color: var(--muted);
  transition: transform .2s ease, border-color .2s ease, color .2s ease;
}
.socials a:hover { transform: translateY(-4px); border-color: var(--accent); color: #fff; }

.contact-email { margin-top: 18px; color: var(--muted); font-size: .95rem; }
.contact-email a { color: var(--accent); font-weight: 500; }
.contact-email a:hover { color: #fff; }

/* Toast — copied-to-clipboard confirmation */
.toast {
  position: fixed; left: 50%; bottom: 28px; transform: translate(-50%, 20px);
  background: rgba(9, 12, 21, 0.96); color: var(--text);
  border: 1px solid var(--accent); border-radius: 999px;
  padding: 12px 22px; font-size: .92rem; font-weight: 500;
  box-shadow: 0 12px 40px rgba(0, 0, 0, .5);
  opacity: 0; pointer-events: none; z-index: 300;
  transition: opacity .25s ease, transform .25s ease;
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }

.footer { text-align: center; padding: 40px 24px; color: var(--muted); font-size: .88rem; border-top: 1px solid var(--border); }

/* ============================================================
   EXPERIENCE TIMELINE
   ============================================================ */
.timeline { position: relative; }
.timeline__item {
  display: grid; grid-template-columns: 160px 1fr; gap: 28px;
  padding: 0 0 34px 0; position: relative;
}
/* vertical line + dot down the left of the content */
.timeline__body {
  position: relative; padding-left: 28px;
  border-left: 1px solid var(--border);
}
.timeline__body::before {
  content: ""; position: absolute; left: -6px; top: 6px;
  width: 11px; height: 11px; border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(110, 168, 254, 0.15);
}
.timeline__date {
  font-family: var(--font-head); font-size: .9rem; color: var(--accent-3);
  font-weight: 500; padding-top: 2px;
}
.timeline__body h3 { font-size: 1.2rem; }
.timeline__org { color: var(--muted); font-size: .95rem; margin: 3px 0 12px; }
.timeline__body ul { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.timeline__body li {
  position: relative; padding-left: 20px; color: #c3cddf; font-size: .96rem;
}
.timeline__body li::before {
  content: "▸"; position: absolute; left: 0; color: var(--accent); opacity: .7;
}

/* ============================================================
   SKILLS & EDUCATION
   ============================================================ */
.se-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 44px; }
.se-col__title {
  font-size: 1.15rem; margin-bottom: 18px; color: var(--text);
  padding-bottom: 10px; border-bottom: 1px solid var(--border);
}
.edu__item { margin-bottom: 20px; }
.edu__item h4 { font-family: var(--font-head); font-size: 1.05rem; }
.edu__org { color: var(--accent-3); font-size: .9rem; margin: 2px 0 6px; }
.edu__note { color: var(--muted); font-size: .88rem; }
.skill-group { margin-bottom: 18px; }
.skill-group h4 {
  font-family: var(--font-head); font-size: .85rem; color: var(--muted);
  text-transform: uppercase; letter-spacing: .6px; margin-bottom: 10px; font-weight: 500;
}
.tags--lang span { color: var(--text); }

/* "To appear" style badge in publications */
.pub__badge {
  display: inline-block; font-size: .72rem; font-weight: 600;
  color: var(--accent-2); background: rgba(177, 140, 255, 0.12);
  border: 1px solid rgba(177, 140, 255, 0.3);
  padding: 2px 9px; border-radius: 999px; margin-left: 6px; letter-spacing: .3px;
}

/* Flash a publication when a project's "Paper ↓" link jumps to it */
@keyframes pubFlash {
  0%   { box-shadow: 0 0 0 0 rgba(110,168,254,0);   border-color: var(--border); background: var(--surface); }
  15%  { box-shadow: 0 0 0 3px rgba(110,168,254,.35), 0 0 26px rgba(110,168,254,.45); border-color: var(--accent); background: rgba(110,168,254,.10); }
  40%  { box-shadow: 0 0 0 0 rgba(110,168,254,0);   border-color: var(--border); background: var(--surface); }
  55%  { box-shadow: 0 0 0 3px rgba(110,168,254,.35), 0 0 26px rgba(110,168,254,.45); border-color: var(--accent); background: rgba(110,168,254,.10); }
  100% { box-shadow: 0 0 0 0 rgba(110,168,254,0);   border-color: var(--border); background: var(--surface); }
}
.pub--flash { animation: pubFlash 1.8s ease; }

/* ============================================================
   PROJECT SLIDES LIGHTBOX
   ============================================================ */
.lightbox {
  position: fixed; inset: 0; z-index: 200;
  display: none; align-items: center; justify-content: center;
  background: rgba(4, 6, 12, 0.92); backdrop-filter: blur(8px);
  padding: 4vh 4vw;
}
.lightbox.open { display: flex; animation: lbFade .25s ease; }
@keyframes lbFade { from { opacity: 0; } to { opacity: 1; } }
.lightbox__stage {
  margin: 0; max-width: 100%; max-height: 100%;
  display: flex; align-items: center; justify-content: center;
}
.lightbox__img {
  max-width: 92vw; max-height: 82vh; object-fit: contain;
  border: 1px solid var(--border); border-radius: 12px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, .6); background: #fff;
}
.lightbox__fallback {
  color: var(--muted); font-size: 1rem; text-align: center; max-width: 460px; line-height: 1.5;
}
.lightbox__fallback code { color: var(--accent-3); }
.lightbox__close {
  position: absolute; top: 18px; right: 22px;
  width: 44px; height: 44px; border-radius: 50%;
  background: rgba(255, 255, 255, .08); border: 1px solid var(--border);
  color: #fff; font-size: 1.7rem; line-height: 1; cursor: pointer;
  display: grid; place-items: center;
  transition: background .2s ease, transform .2s ease;
}
.lightbox__close:hover { background: rgba(255, 255, 255, .18); transform: scale(1.05); }
.lightbox__nav {
  position: absolute; top: 50%; transform: translateY(-50%);
  width: 52px; height: 52px; border-radius: 50%;
  background: rgba(255, 255, 255, .08); border: 1px solid var(--border);
  color: #fff; font-size: 2rem; line-height: 1; cursor: pointer;
  display: grid; place-items: center;
  transition: background .2s ease, border-color .2s ease;
}
.lightbox__nav:hover { background: rgba(110, 168, 254, .25); border-color: var(--accent); }
.lightbox__prev { left: 20px; }
.lightbox__next { right: 20px; }
.lightbox__counter {
  position: absolute; bottom: 22px; left: 50%; transform: translateX(-50%);
  color: var(--muted); font-family: var(--font-head); font-size: .9rem;
  background: rgba(0, 0, 0, .45); padding: 5px 14px; border-radius: 999px; border: 1px solid var(--border);
}
@media (max-width: 600px) {
  .lightbox__nav { width: 42px; height: 42px; font-size: 1.5rem; }
  .lightbox__prev { left: 8px; }
  .lightbox__next { right: 8px; }
  .lightbox__img { max-width: 96vw; }
}

/* ============================================================
   SCROLL REVEAL ANIMATION
   ============================================================ */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .7s ease, transform .7s ease; }
.reveal.visible { opacity: 1; transform: none; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 860px) {
  .orbit { display: none; }
  .grid--3 { grid-template-columns: 1fr 1fr; }
  .about { grid-template-columns: 1fr; }
  .about__photo { max-width: 220px; }
  .se-grid { grid-template-columns: 1fr; gap: 36px; }
  .timeline__item { grid-template-columns: 130px 1fr; gap: 18px; }
}
@media (max-width: 680px) {
  .nav__toggle { display: flex; }
  .nav__links {
    position: absolute; top: 100%; right: 16px; left: 16px;
    flex-direction: column; align-items: flex-start; gap: 18px;
    background: rgba(9, 12, 21, 0.96); backdrop-filter: blur(12px);
    border: 1px solid var(--border); border-radius: var(--radius);
    padding: 22px 24px; transform: translateY(-10px); opacity: 0; pointer-events: none;
    transition: opacity .25s ease, transform .25s ease;
  }
  .nav__links.open { opacity: 1; transform: none; pointer-events: auto; }
  .grid--2, .grid--3 { grid-template-columns: 1fr; }
  .hero { padding-top: 110px; }
  /* stack the timeline: date sits above the content */
  .timeline__item { grid-template-columns: 1fr; gap: 6px; }
  .timeline__date { padding-top: 0; }
}

/* Respect users who prefer no motion */
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
}

/* ============================================================
   LIGHT THEME — opt-in via [data-theme="light"]; dark is default
   ============================================================ */
:root[data-theme="light"] {
  --bg:        #eef2f8;
  --bg-2:      #ffffff;
  --surface:   rgba(24, 39, 74, 0.045);
  --border:    rgba(24, 39, 74, 0.14);
  --text:      #1b2438;
  --muted:     #566079;
  --accent:    #2f6fd6;
  --accent-2:  #7a53e8;
  --accent-3:  #128a7d;
}
:root[data-theme="light"] body::before {
  background:
    radial-gradient(46% 42% at 88% -4%, rgba(255, 199, 92, 0.32), transparent 60%),
    radial-gradient(45% 45% at 8% 8%, rgba(110, 168, 254, 0.10), transparent 60%);
}
:root[data-theme="light"] .nav.scrolled { background: rgba(255, 255, 255, 0.82); }
:root[data-theme="light"] .nav__links { background: rgba(255, 255, 255, 0.97); }
:root[data-theme="light"] .hero__name {
  background: linear-gradient(180deg, #17203a 30%, #46506e);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
:root[data-theme="light"] .orbit__ring { border-color: rgba(24, 39, 74, 0.16); }
:root[data-theme="light"] .about__photo-fallback { background: linear-gradient(145deg, #dbe3f2, #eef0fb); }
:root[data-theme="light"] .tags span {
  color: var(--accent-3); background: rgba(18, 138, 125, 0.09); border-color: rgba(18, 138, 125, 0.28);
}
:root[data-theme="light"] .tags--lang span { color: var(--text); }
:root[data-theme="light"] .about__text p { color: #2a3346; }
:root[data-theme="light"] .timeline__body li { color: #2a3346; }
:root[data-theme="light"] .pub__authors { color: #2a3346; }
:root[data-theme="light"] .pub__authors b { color: #17203a; }