:root {
  --bg: #0b0f14;
  --surface: #121820;
  --surface-alt: #17202b;
  --border: #222d3a;
  --text: #e6edf3;
  --text-muted: #9aa7b4;
  --accent: #2dd4bf;
  --accent-dim: #1f9c8c;
  --font-display: "Libre Baskerville", serif;
  --font-body: "Inter", sans-serif;
  --nav-height: 80px;
  --container: 1100px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.6;
}

a {
  color: inherit;
  text-decoration: none;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

.skip-link {
  position: absolute;
  top: -48px;
  left: 16px;
  z-index: 200;
  background: var(--accent);
  color: #06201c;
  font-weight: 600;
  font-size: 14px;
  padding: 10px 18px;
  border-radius: 8px;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 16px;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

section {
  scroll-margin-top: var(--nav-height);
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Nav ---------- */

.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  background: rgba(11, 15, 20, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.nav_container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav_logo {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 2px;
  line-height: 1.15;
}

.nav_logo_name {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
}

.nav_logo_sub {
  font-family: var(--font-body);
  font-size: 11px;
  font-weight: 500;
  color: var(--text-muted);
}

.nav_links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav_links a:not(.btn) {
  color: var(--text-muted);
  font-size: 15px;
  font-weight: 500;
  transition: color 0.2s ease;
}

.nav_links a:not(.btn):hover {
  color: var(--text);
}

.nav_links a.active {
  color: var(--accent);
}

.nav_toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav_toggle span {
  width: 22px;
  height: 2px;
  background: var(--text);
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.nav.is-open .nav_toggle span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav.is-open .nav_toggle span:nth-child(2) {
  opacity: 0;
}
.nav.is-open .nav_toggle span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface-alt);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}

.btn:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #06201c;
}

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

.btn-sm {
  padding: 8px 16px;
  font-size: 13px;
}

/* ---------- Hero ---------- */

.hero {
  position: relative;
  padding: 96px 0 72px;
  background-image: radial-gradient(circle at 15% 20%, rgba(45, 212, 191, 0.12), transparent 40%),
    radial-gradient(circle at 85% 0%, rgba(45, 212, 191, 0.08), transparent 45%),
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: auto, auto, 40px 40px, 40px 40px;
  overflow: hidden;
}

.hero_container {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 48px;
}

.cloud {
  position: absolute;
  z-index: 0;
  opacity: 0.22;
  filter: grayscale(1) brightness(2.2);
  pointer-events: none;
}

.cloud1 {
  left: 6%;
  top: 18%;
  width: 90px;
}

.cloud2 {
  right: 10%;
  top: 8%;
  width: 70px;
}

.mountain {
  position: absolute;
  z-index: 0;
  left: 50%;
  bottom: -6px;
  transform: translateX(-50%);
  width: min(70%, 620px);
  opacity: 0.18;
  filter: grayscale(1) brightness(1.6);
  pointer-events: none;
}

.hero_text .eyebrow {
  color: var(--accent);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.ola {
  font-family: var(--font-display);
  font-size: 44px;
  font-weight: 700;
  margin: 10px 0 8px;
  color: var(--text);
}

.ola span {
  color: var(--accent);
  text-decoration: none;
}

.hero_role {
  font-size: 18px;
  color: var(--text-muted);
  max-width: 460px;
  margin-bottom: 28px;
}

.hero_cta {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.hero_portrait {
  position: relative;
  flex-shrink: 0;
}

.ola_img {
  width: 220px;
  height: 220px;
  border-radius: 50%;
  object-fit: cover;
  object-position: 50% 18%;
  border: 3px solid var(--accent);
  box-shadow: 0 0 0 10px rgba(45, 212, 191, 0.08);
}

@media (max-width: 760px) {
  .hero_container {
    flex-direction: column-reverse;
    text-align: center;
  }
  .hero_cta {
    justify-content: center;
  }
  .hero_role {
    margin-left: auto;
    margin-right: auto;
  }
  .ola_img {
    width: 160px;
    height: 160px;
  }
}

/* ---------- Pitch hero (elevator-pitch.html) ---------- */

.pitch_hero {
  padding: 96px 0 72px;
  text-align: center;
  background-image: radial-gradient(circle at 50% 0%, rgba(45, 212, 191, 0.12), transparent 50%),
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: auto, 40px 40px, 40px 40px;
}

.pitch_hero h1 {
  font-family: var(--font-display);
  font-size: 38px;
  margin: 10px 0 14px;
  color: var(--text);
}

.pitch_hero .lead {
  color: var(--text-muted);
  max-width: 520px;
  margin: 0 auto 28px;
  font-size: 17px;
}

.pitch_hero .hero_cta {
  justify-content: center;
}

/* ---------- Section headings ---------- */

.section {
  padding: 80px 0;
  border-top: 1px solid var(--border);
}

.section_head {
  text-align: center;
  margin-bottom: 48px;
}

.section_head .eyebrow {
  color: var(--accent);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.section_head h2 {
  font-family: var(--font-display);
  font-size: 30px;
  margin-top: 8px;
}

/* ---------- About ---------- */

.about_card {
  max-width: 720px;
  margin: 0 auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 32px;
  text-align: center;
}

.about_card p {
  color: var(--text-muted);
  font-size: 16px;
}

.about_card strong {
  color: var(--text);
}

/* ---------- Experience / Timeline ---------- */

.timeline {
  max-width: 720px;
  margin: 0 auto;
  position: relative;
  padding-left: 28px;
  border-left: 2px solid var(--border);
}

.timeline_item {
  position: relative;
  padding-bottom: 32px;
}

.timeline_item:last-child {
  padding-bottom: 0;
}

.timeline_item::before {
  content: "";
  position: absolute;
  left: -34px;
  top: 4px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--bg), 0 0 0 5px var(--border);
}

.timeline_head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
}

.timeline_head h3 {
  font-size: 17px;
}

.timeline_date {
  color: var(--accent);
  font-size: 13px;
  font-weight: 600;
  white-space: nowrap;
}

.timeline_org {
  color: var(--text-muted);
  font-size: 13px;
  font-weight: 600;
  margin: 2px 0 8px;
}

.timeline_item > p:not(.timeline_org) {
  color: var(--text-muted);
  font-size: 15px;
}

/* ---------- Skills ---------- */

.skills_grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 20px;
}

.skills_group {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
}

.skills_group h3 {
  font-size: 15px;
  color: var(--accent);
  margin-bottom: 16px;
}

.skills_badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.badge {
  background: var(--surface-alt);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 13px;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: 999px;
}

/* ---------- Projects ---------- */

.projects_grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.project_card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  overflow: hidden;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.project_card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
}

.project_thumb {
  margin: -28px -28px 0;
  width: calc(100% + 56px);
  max-width: none;
  height: 170px;
  object-fit: cover;
}

.project_thumb-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  background: radial-gradient(circle at 50% 42%, rgba(45, 212, 191, 0.2), transparent 60%), var(--surface-alt);
}

.project_thumb-icon img {
  width: 84px;
  height: 84px;
  border-radius: 20px;
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.4);
}

.project_stat {
  color: var(--text-muted);
  font-size: 13px;
}

.project_stat strong {
  color: var(--accent);
  font-size: 15px;
}

.project_links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.project_card h3 {
  font-size: 20px;
}

.project_role {
  color: var(--accent);
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.project_card p {
  color: var(--text-muted);
  font-size: 15px;
}

.project_tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.project_card .btn {
  align-self: flex-start;
}

/* ---------- Video (elevator-pitch.html) ---------- */

.video_card {
  max-width: 720px;
  margin: 0 auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

.video_frame {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  border-radius: 10px;
  overflow: hidden;
  background: var(--surface-alt);
}

.video_frame iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

/* ---------- Publications (research.html) ---------- */

.pub_grid {
  display: grid;
  gap: 24px;
  max-width: 820px;
  margin: 0 auto;
}

.pub_card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.pub_card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.pub_meta {
  display: flex;
  align-items: center;
  gap: 10px;
}

.badge-published {
  background: var(--accent);
  border-color: var(--accent);
  color: #06201c;
  font-weight: 700;
}

.badge-preprint {
  background: transparent;
}

.pub_date {
  color: var(--text-muted);
  font-size: 13px;
}

.pub_card h3 {
  font-size: 19px;
  line-height: 1.35;
}

.pub_authors {
  color: var(--text-muted);
  font-size: 14px;
}

.pub_authors strong {
  color: var(--text);
}

.pub_venue {
  color: var(--text-muted);
  font-size: 13px;
  font-style: italic;
}

.pub_card > p:not(.pub_authors):not(.pub_venue) {
  color: var(--text-muted);
  font-size: 15px;
}

.testimonials_head {
  margin-top: 56px;
}

.testimonial_grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  max-width: 820px;
  margin: 0 auto;
}

.testimonial_card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.testimonial_card > p:first-child {
  color: var(--text-muted);
  font-size: 14px;
  font-style: italic;
  flex-grow: 1;
  margin-bottom: 10px;
}

.testimonial_name {
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
}

.testimonial_role {
  color: var(--accent);
  font-size: 12px;
}

.note_card {
  max-width: 820px;
  margin: 32px auto 0;
  text-align: center;
  background: var(--surface-alt);
}

.note_card .project_links {
  justify-content: center;
}

/* ---------- Contact ---------- */

.contact_card {
  max-width: 560px;
  margin: 0 auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 36px;
  text-align: center;
}

.contact_links {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: center;
  margin-bottom: 20px;
  font-size: 15px;
}

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

.contact_links img {
  width: 16px;
  height: 16px;
  vertical-align: middle;
  margin-right: 6px;
}

.contact_socials {
  display: flex;
  justify-content: center;
  gap: 18px;
}

.contact_socials svg {
  fill: var(--text-muted);
  transition: fill 0.2s ease, transform 0.2s ease;
}

.contact_socials a:hover svg {
  fill: var(--accent);
  transform: scale(1.15);
}

/* ---------- Footer ---------- */

.footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
}

/* ---------- Scroll reveal ---------- */

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- Mobile nav ---------- */

@media (max-width: 760px) {
  .nav_toggle {
    display: flex;
  }

  .nav_links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .nav.is-open .nav_links {
    max-height: 400px;
  }

  .nav_links li {
    width: 100%;
  }

  .nav_links a {
    display: block;
    width: 100%;
    padding: 16px 24px;
    border-top: 1px solid var(--border);
  }
}