/* Aurora Robotics — Research Portfolio theme */
:root {
  --aurora-black: #000000;
  --aurora-lime: #d4ff00;
  --aurora-lime-dim: #a8c800;
  --aurora-lime-glow: rgba(212, 255, 0, 0.35);
  --aurora-surface: #0a0a0a;
  --aurora-surface-raised: #111111;
  --aurora-border: #1f1f1f;
  --aurora-border-accent: rgba(212, 255, 0, 0.25);
  --aurora-text: #e8e8e8;
  --aurora-text-muted: #8a8a8a;
  --font-display: "Orbitron", system-ui, sans-serif;
  --font-body: "Rajdhani", system-ui, sans-serif;
  --header-h: 4.5rem;
  --container: min(72rem, 92vw);
  --clip-corner: polygon(0 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 1.125rem;
  font-weight: 500;
  line-height: 1.6;
  color: var(--aurora-text);
  background: var(--aurora-black);
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--aurora-lime);
  text-decoration: none;
  transition: color 0.2s, opacity 0.2s;
}

a:hover {
  color: #fff;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  z-index: 9999;
  padding: 0.5rem 1rem;
  background: var(--aurora-lime);
  color: var(--aurora-black);
  font-weight: 700;
}

.skip-link:focus {
  top: 1rem;
}

.container {
  width: var(--container);
  margin-inline: auto;
}

/* Navigation */
.site-header {
  position: relative;
  border-bottom: 1px solid var(--aurora-border);
}

.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  height: var(--header-h);
  padding: 0 clamp(1rem, 4vw, 2rem);
  background: rgba(0, 0, 0, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--aurora-border);
}

.nav__brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--aurora-text);
  text-decoration: none;
}

.nav__brand:hover {
  color: var(--aurora-lime);
}

.nav__logo {
  filter: drop-shadow(0 0 8px var(--aurora-lime-glow));
}

.nav__title {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.nav__menu {
  display: flex;
  gap: 2rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav__menu a {
  font-family: var(--font-display);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--aurora-text-muted);
}

.nav__menu a:hover {
  color: var(--aurora-lime);
}

.nav__toggle {
  display: none;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border: 1px solid var(--aurora-border-accent);
  background: var(--aurora-surface);
  cursor: pointer;
  clip-path: var(--clip-corner);
}

.nav__toggle-bar,
.nav__toggle-bar::before,
.nav__toggle-bar::after {
  display: block;
  width: 1.25rem;
  height: 2px;
  margin: 0 auto;
  background: var(--aurora-lime);
  transition: transform 0.2s;
}

.nav__toggle-bar::before,
.nav__toggle-bar::after {
  content: "";
}

.nav__toggle-bar::before {
  transform: translateY(-6px);
}

.nav__toggle-bar::after {
  transform: translateY(4px);
}

/* Hero */
.hero {
  position: relative;
  padding: clamp(3rem, 8vw, 6rem) clamp(1rem, 4vw, 2rem) clamp(4rem, 10vw, 7rem);
  overflow: hidden;
}

.hero__grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--aurora-border) 1px, transparent 1px),
    linear-gradient(90deg, var(--aurora-border) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 80% 70% at 50% 40%, black 20%, transparent 75%);
  opacity: 0.5;
  pointer-events: none;
}

.hero__grid::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 40%, var(--aurora-black) 100%);
}

.hero__content {
  position: relative;
  max-width: 42rem;
  margin-inline: auto;
  text-align: center;
}

.hero__banner {
  margin-inline: auto;
  margin-bottom: 1.5rem;
  max-width: min(520px, 90vw);
  filter: drop-shadow(0 0 24px var(--aurora-lime-glow));
}

.hero__tagline {
  font-family: var(--font-display);
  font-size: clamp(0.75rem, 2vw, 0.9rem);
  font-weight: 600;
  letter-spacing: 0.35em;
  text-transform: uppercase;
  color: var(--aurora-lime);
  margin: 0 0 0.75rem;
}

.hero__motto {
  font-family: var(--font-display);
  font-size: clamp(1.1rem, 3vw, 1.5rem);
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--aurora-text);
  margin: 0 0 1rem;
  line-height: 1.35;
}

.hero__motto-accent {
  color: var(--aurora-lime);
}

.hero__lead {
  font-size: clamp(1.05rem, 2.5vw, 1.25rem);
  color: var(--aurora-text-muted);
  margin: 0 0 2rem;
  max-width: 36rem;
  margin-inline: auto;
}

.hero__stats {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.5rem 2.5rem;
  margin-bottom: 2rem;
}

.stat {
  text-align: center;
}

.stat__value {
  display: block;
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 800;
  color: var(--aurora-lime);
  line-height: 1;
}

.stat__label {
  font-size: 0.85rem;
  color: var(--aurora-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* Buttons */
.btn {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  padding: 0.9rem 2rem;
  border: none;
  cursor: pointer;
  clip-path: var(--clip-corner);
  transition: transform 0.15s, box-shadow 0.2s;
}

.btn--primary {
  background: var(--aurora-lime);
  color: var(--aurora-black);
}

.btn--primary:hover {
  color: var(--aurora-black);
  transform: translateY(-2px);
  box-shadow: 0 0 24px var(--aurora-lime-glow);
}

/* Sections */
.section {
  padding: clamp(3rem, 6vw, 5rem) 0;
}

.section__title {
  font-family: var(--font-display);
  font-size: clamp(1rem, 2.5vw, 1.15rem);
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  margin: 0 0 2rem;
  color: var(--aurora-text);
}

.section__accent {
  color: var(--aurora-lime);
  margin-right: 0.5rem;
}

/* About */
.about {
  background: var(--aurora-surface);
  border-block: 1px solid var(--aurora-border);
}

.about__grid {
  display: grid;
  gap: 2.5rem;
}

@media (min-width: 768px) {
  .about__grid {
    grid-template-columns: 1.2fr 1fr;
    align-items: start;
  }
}

.about__text {
  margin: 0;
  color: var(--aurora-text-muted);
  font-size: 1.15rem;
}

.about__pillars {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.about__pillars li {
  padding: 1rem 1.25rem;
  border: 1px solid var(--aurora-border);
  border-left: 3px solid var(--aurora-lime);
  background: var(--aurora-surface-raised);
  clip-path: var(--clip-corner);
}

.about__pillars strong {
  display: block;
  font-family: var(--font-display);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--aurora-lime);
  margin-bottom: 0.35rem;
}

.about__pillars span {
  color: var(--aurora-text-muted);
  font-size: 1rem;
}

/* Filters */
.filter-bar .container {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.filter-btn {
  font-family: var(--font-display);
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 0.6rem 1rem;
  border: 1px solid var(--aurora-border);
  background: var(--aurora-surface);
  color: var(--aurora-text-muted);
  cursor: pointer;
  clip-path: var(--clip-corner);
  transition: border-color 0.2s, color 0.2s, background 0.2s;
}

.filter-btn:hover,
.filter-btn[aria-selected="true"] {
  border-color: var(--aurora-lime);
  color: var(--aurora-lime);
  background: rgba(212, 255, 0, 0.06);
}

.search {
  width: 100%;
  max-width: 32rem;
  padding: 0.85rem 1.25rem;
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 500;
  color: var(--aurora-text);
  background: var(--aurora-surface);
  border: 1px solid var(--aurora-border);
  clip-path: var(--clip-corner);
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.search::placeholder {
  color: var(--aurora-text-muted);
}

.search:focus {
  border-color: var(--aurora-lime);
  box-shadow: 0 0 0 1px var(--aurora-lime-glow);
}

/* Catalogue */
.catalogue__count {
  font-size: 0.9rem;
  color: var(--aurora-text-muted);
  margin: -1rem 0 2rem;
}

.catalogue__empty {
  text-align: center;
  color: var(--aurora-text-muted);
  padding: 3rem;
}

.catalogue__empty.hidden,
.hidden {
  display: none !important;
}

.category-block {
  margin-bottom: 3.5rem;
}

.category-block__header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--aurora-border-accent);
}

.category-block__title {
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin: 0;
  color: var(--aurora-lime);
}

.category-block__count {
  font-size: 0.85rem;
  color: var(--aurora-text-muted);
}

.paper-grid {
  display: grid;
  gap: 1.25rem;
}

@media (min-width: 640px) {
  .paper-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .paper-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.paper-card {
  display: flex;
  flex-direction: column;
  padding: 1.25rem 1.35rem;
  background: var(--aurora-surface);
  border: 1px solid var(--aurora-border);
  clip-path: var(--clip-corner);
  cursor: pointer;
  text-align: left;
  color: inherit;
  font: inherit;
  width: 100%;
  transition: border-color 0.2s, transform 0.15s, box-shadow 0.2s;
}

.paper-card:hover,
.paper-card:focus-visible {
  border-color: var(--aurora-lime);
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5), 0 0 0 1px var(--aurora-border-accent);
  outline: none;
}

.paper-card__badge {
  font-family: var(--font-display);
  font-size: 0.6rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--aurora-lime-dim);
  margin-bottom: 0.5rem;
}

.paper-card__title {
  font-family: var(--font-body);
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.35;
  margin: 0 0 0.75rem;
  color: var(--aurora-text);
  flex: 1;
}

.paper-card__meta {
  font-size: 0.9rem;
  color: var(--aurora-text-muted);
  margin: 0 0 0.5rem;
}

.paper-card__venue {
  font-size: 0.8rem;
  color: var(--aurora-lime-dim);
  margin: 0;
  margin-top: auto;
  padding-top: 0.75rem;
  border-top: 1px solid var(--aurora-border);
}

.paper-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-top: 0.75rem;
}

.tag {
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  background: rgba(212, 255, 0, 0.08);
  border: 1px solid var(--aurora-border-accent);
  color: var(--aurora-text-muted);
}

.tag--more {
  background: transparent;
  border-style: dashed;
}

/* Modal */
.paper-modal {
  width: min(42rem, 94vw);
  max-height: 90vh;
  padding: 0;
  border: 1px solid var(--aurora-lime);
  background: var(--aurora-surface-raised);
  color: var(--aurora-text);
  clip-path: var(--clip-corner);
}

.paper-modal::backdrop {
  background: rgba(0, 0, 0, 0.85);
}

.paper-modal__inner {
  position: relative;
  padding: 2rem 1.75rem;
  overflow-y: auto;
  max-height: 90vh;
}

.paper-modal__close {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  width: 2.25rem;
  height: 2.25rem;
  font-size: 1.5rem;
  line-height: 1;
  border: 1px solid var(--aurora-border);
  background: var(--aurora-black);
  color: var(--aurora-lime);
  cursor: pointer;
  clip-path: var(--clip-corner);
}

.paper-modal__close:hover {
  background: var(--aurora-lime);
  color: var(--aurora-black);
}

.modal__category {
  font-family: var(--font-display);
  font-size: 0.65rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--aurora-lime);
  margin: 0 0 0.5rem;
}

.modal__title {
  font-family: var(--font-body);
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1.3;
  margin: 0 0 1rem;
  padding-right: 2rem;
}

.modal__authors,
.modal__venue {
  font-size: 0.95rem;
  color: var(--aurora-text-muted);
  margin: 0 0 0.5rem;
}

.modal__venue strong {
  color: var(--aurora-lime-dim);
}

.modal__section-title {
  font-family: var(--font-display);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--aurora-lime);
  margin: 1.5rem 0 0.75rem;
}

.modal__overview {
  color: var(--aurora-text-muted);
  margin: 0;
}

.modal__list {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--aurora-text-muted);
}

.modal__list li {
  margin-bottom: 0.5rem;
}

.modal__tech {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--aurora-border);
  padding: 2rem 0;
  margin-top: 2rem;
}

.site-footer__inner {
  display: flex;
  align-items: center;
  gap: 1rem;
  color: var(--aurora-text-muted);
  font-size: 0.9rem;
}

.site-footer__logo {
  opacity: 0.85;
}

/* Mobile nav */
@media (max-width: 768px) {
  .nav__toggle {
    display: block;
  }

  .nav__menu {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    padding: 1rem;
    background: var(--aurora-black);
    border-bottom: 1px solid var(--aurora-border);
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.25s, opacity 0.25s;
  }

  .nav__menu.is-open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav__menu li {
    border-bottom: 1px solid var(--aurora-border);
  }

  .nav__menu a {
    display: block;
    padding: 1rem 0;
  }
}