/* Projects hub — academic landing (professional project index) */

:root {
  --hub-bg: #eef1f8;
  --hub-surface: #ffffff;
  --hub-ink: #12151c;
  --hub-muted: #5a6270;
  --hub-accent: #2c4a8c;
  --hub-accent2: #5c3d8a;
  --hub-border: rgba(18, 21, 28, 0.07);
  --hub-shadow: 0 4px 28px rgba(18, 28, 45, 0.07);
  --hub-shadow-hover: 0 20px 48px rgba(18, 28, 45, 0.11);
  --hub-radius: 16px;
  --hub-ease: cubic-bezier(0.4, 0, 0.2, 1);
  --hub-font-display: "Instrument Sans", "Noto Sans", -apple-system, BlinkMacSystemFont, sans-serif;
  --hub-font-body: "Noto Sans", -apple-system, BlinkMacSystemFont, sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body.hub-page {
  margin: 0;
  min-height: 100vh;
  font-family: var(--hub-font-body);
  color: var(--hub-ink);
  background: var(--hub-bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.hub-bg {
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 90% 55% at 50% -15%, rgba(44, 74, 140, 0.14), transparent 55%),
    radial-gradient(ellipse 70% 45% at 100% 30%, rgba(92, 61, 138, 0.09), transparent 50%),
    radial-gradient(ellipse 55% 40% at 0% 85%, rgba(44, 74, 140, 0.07), transparent 50%);
  z-index: 0;
}

.hub-noise {
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.035;
  z-index: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

.hub-wrap {
  position: relative;
  z-index: 1;
  max-width: 1120px;
  margin: 0 auto;
  padding: 3rem 1.5rem 4.5rem;
}

.hub-back {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  margin-bottom: 1.75rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--hub-accent);
  text-decoration: none;
  padding: 0.4rem 0.2rem;
  border-radius: 8px;
  transition:
    color 0.2s ease,
    transform 0.25s var(--hub-ease),
    background 0.2s ease;
}

.hub-back:hover {
  color: var(--hub-accent2);
  background: rgba(44, 74, 140, 0.06);
}

.hub-back:focus-visible {
  outline: 2px solid var(--hub-accent);
  outline-offset: 3px;
}

.hub-back-icon {
  display: inline-block;
  transition: transform 0.25s var(--hub-ease);
}

.hub-back:hover .hub-back-icon {
  transform: translateX(-3px);
}

.hub-header {
  text-align: center;
  margin-bottom: 3rem;
  animation: hubFade 0.75s var(--hub-ease) both;
}

.hub-kicker {
  display: inline-block;
  font-family: var(--hub-font-display);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--hub-accent);
  margin-bottom: 0.85rem;
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  background: rgba(44, 74, 140, 0.08);
  border: 1px solid rgba(44, 74, 140, 0.12);
}

.hub-title {
  margin: 0 0 0.65rem;
  font-family: var(--hub-font-display);
  font-size: clamp(1.85rem, 4.2vw, 2.45rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--hub-ink);
  line-height: 1.15;
}

.hub-sub {
  margin: 0 auto;
  max-width: 38rem;
  font-size: 1.05rem;
  color: var(--hub-muted);
}

.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.hub-card {
  display: flex;
  flex-direction: column;
  position: relative;
  background: var(--hub-surface);
  border: 1px solid var(--hub-border);
  border-radius: var(--hub-radius);
  padding: 1.6rem 1.6rem 1.4rem;
  text-decoration: none;
  color: inherit;
  box-shadow: var(--hub-shadow);
  overflow: hidden;
  isolation: isolate;
  transition:
    transform 0.4s var(--hub-ease),
    box-shadow 0.4s var(--hub-ease),
    border-color 0.3s ease;
  animation: hubFade 0.7s var(--hub-ease) both;
}

.hub-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: linear-gradient(90deg, var(--hub-accent), var(--hub-accent2));
  transform: scaleX(0.35);
  transform-origin: left;
  opacity: 0.65;
  transition:
    transform 0.45s var(--hub-ease),
    opacity 0.3s ease;
}
.hub-card:hover::before {
  transform: scaleX(1);
  opacity: 1;
}

.hub-card:nth-child(1) {
  animation-delay: 0.06s;
}
.hub-card:nth-child(2) {
  animation-delay: 0.14s;
}
.hub-card:nth-child(3) {
  animation-delay: 0.22s;
}

.hub-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--hub-shadow-hover);
  border-color: rgba(44, 74, 140, 0.18);
}

.hub-card:focus-visible {
  outline: 2px solid var(--hub-accent);
  outline-offset: 3px;
}

.hub-card-badge {
  align-self: flex-start;
  font-family: var(--hub-font-display);
  font-size: 0.66rem;
  font-weight: 700;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  padding: 0.32rem 0.6rem;
  border-radius: 8px;
  background: linear-gradient(135deg, rgba(44, 74, 140, 0.1), rgba(92, 61, 138, 0.08));
  color: var(--hub-accent);
  margin-bottom: 0.75rem;
}

.hub-card-title {
  margin: 0 0 0.5rem;
  font-family: var(--hub-font-display);
  font-size: 1.22rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--hub-ink);
  line-height: 1.35;
}

.hub-card-meta {
  margin: 0 0 0.85rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--hub-accent);
  opacity: 0.92;
}

.hub-card-desc {
  margin: 0 0 1.15rem;
  flex: 1;
  font-size: 0.93rem;
  color: var(--hub-muted);
  line-height: 1.6;
}

.hub-card-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--hub-font-display);
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--hub-accent);
}

.hub-card-cta span {
  transition: transform 0.3s var(--hub-ease);
}

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

.hub-footer {
  margin-top: 3.25rem;
  padding-top: 1.75rem;
  border-top: 1px solid var(--hub-border);
  text-align: center;
  font-size: 0.84rem;
  color: var(--hub-muted);
}

.hub-footer a {
  color: var(--hub-accent);
  text-decoration: none;
  font-weight: 600;
  transition: color 0.2s ease;
}

.hub-footer a:hover {
  text-decoration: underline;
  color: var(--hub-accent2);
}

@keyframes hubFade {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .hub-card,
  .hub-header {
    animation: none;
  }
  .hub-card:hover {
    transform: none;
  }
  .hub-card::before {
    transform: scaleX(1);
    opacity: 1;
  }
  .hub-back:hover .hub-back-icon,
  .hub-card:hover .hub-card-cta span {
    transform: none;
  }
}