* { box-sizing: border-box; }
:root {
  color-scheme: dark;
  --bg: #020611;
  --panel: rgba(5, 13, 30, 0.72);
  --panel-2: rgba(10, 24, 52, 0.72);
  --ink: #f7f7f4;
  --muted: rgba(247, 247, 244, 0.68);
  --soft: rgba(247, 247, 244, 0.48);
  --blue: #6ca4ff;
  --line: rgba(108, 164, 255, 0.24);
}
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 78% 0%, rgba(67, 105, 214, 0.18), transparent 32rem),
    linear-gradient(180deg, #020611 0%, #050b15 100%);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", Inter, "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: geometricPrecision;
}
a { color: inherit; text-decoration: none; }
a:focus-visible, button:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 6px;
  border-radius: 2px;
}
.site-header {
  position: fixed;
  top: 0;
  left: 50%;
  z-index: 20;
  width: 80vw;
  margin: 0 auto;
  padding: 28px 0;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  background: linear-gradient(180deg, rgba(2, 6, 17, 0.94), rgba(2, 6, 17, 0));
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 1.08rem;
  font-weight: 560;
  line-height: 1;
  letter-spacing: 0;
  white-space: nowrap;
}
.brand-icon {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  object-fit: cover;
  flex: 0 0 auto;
}
.nav {
  display: flex;
  align-items: center;
  gap: clamp(12px, 1.55vw, 22px);
}
.nav a,
.menu-button {
  color: rgba(247, 247, 244, 0.86);
  font-size: 0.6rem;
  font-weight: 650;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  white-space: nowrap;
}
.nav .active,
.nav [aria-current="page"] { color: var(--blue); }
.menu-button {
  display: inline-grid;
  place-items: center;
  width: 30px;
  height: 26px;
}
.menu-button span,
.menu-button::before,
.menu-button::after {
  content: "";
  display: block;
  width: 20px;
  height: 1px;
  background: rgba(247, 247, 244, 0.82);
}
.menu-button span { margin: 4px 0; }
main {
  width: 80vw;
  margin: 0 auto;
  padding: 124px 0 96px;
}
.section-head {
  margin: 0 0 28px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--blue);
}
.page-title {
  margin: 0 0 18px;
  max-width: 980px;
  font-size: clamp(2.2rem, 5vw, 4.7rem);
  font-weight: 650;
  line-height: 0.98;
  letter-spacing: 0;
}
.intro {
  max-width: 860px;
  margin: 0 0 34px;
  color: var(--muted);
  font-size: clamp(1rem, 1.4vw, 1.35rem);
  line-height: 1.62;
}
.button-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 22px;
  border: 1px solid rgba(108, 164, 255, 0.46);
  color: var(--ink);
  font-size: 0.68rem;
  font-weight: 720;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.button-link:hover { border-color: var(--blue); color: var(--blue); }
.grid { display: grid; gap: 18px; }
.cards-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.cards-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.card {
  border: 1px solid rgba(108, 164, 255, 0.22);
  border-radius: 7px;
  background:
    linear-gradient(180deg, rgba(20, 45, 88, 0.74), rgba(2, 6, 17, 0.58)),
    var(--panel);
  padding: 22px;
}
.card h2, .card h3 {
  margin: 0 0 12px;
  font-size: 1.05rem;
  line-height: 1.15;
  font-weight: 680;
}
.card p, .card li {
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.58;
}
.card ul { margin: 12px 0 0; padding-left: 18px; }
.rule {
  width: 34px;
  height: 1px;
  margin: 18px 0 20px;
  background: var(--blue);
}
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  align-items: start;
}
.person-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 20px;
}
.person {
  padding: 0;
  background: transparent;
  border: 0;
}
.person img {
  width: 118px;
  height: 118px;
  border-radius: 50%;
  object-fit: cover;
  display: block;
  margin-bottom: 14px;
  border: 1px solid rgba(108, 164, 255, 0.32);
}
.person h3 { margin: 0 0 6px; font-size: 1rem; }
.person p { margin: 0; color: var(--muted); font-size: 0.82rem; line-height: 1.5; }
.person a { color: var(--blue); }
.list-row {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 18px;
  padding: 18px 0;
  border-top: 1px solid rgba(108, 164, 255, 0.16);
}
.list-row .num {
  color: var(--blue);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.1em;
}
.list-row p { margin: 0; color: var(--muted); font-size: 0.86rem; line-height: 1.55; }
.list-row strong { color: var(--ink); font-weight: 700; }
.list-row a,
.paper-link {
  color: var(--blue);
  overflow-wrap: anywhere;
  word-break: break-word;
}
.list-row a:hover,
.paper-link:hover {
  color: var(--ink);
}
.prose-section {
  max-width: 880px;
  margin-top: 44px;
  padding-top: 28px;
  border-top: 1px solid rgba(108, 164, 255, 0.18);
}
.prose-section h2 {
  margin: 34px 0 12px;
  color: var(--ink);
  font-size: clamp(1.18rem, 1.7vw, 1.65rem);
  line-height: 1.12;
  font-weight: 680;
}
.prose-section h2:first-child { margin-top: 0; }
.prose-section p {
  margin: 0 0 16px;
  color: var(--muted);
  font-size: clamp(0.98rem, 1.2vw, 1.18rem);
  line-height: 1.72;
}
.course-section {
  margin-top: 54px;
  padding-top: 32px;
  border-top: 1px solid rgba(108, 164, 255, 0.18);
}
.course-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 22px;
}
.course-heading h2 {
  margin: 0 0 8px;
  font-size: clamp(1.5rem, 2.2vw, 2.4rem);
  line-height: 1;
}
.course-heading p {
  margin: 0;
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.5;
}
.course-heading .course-description {
  margin-top: 10px;
  max-width: 820px;
  font-size: 0.92rem;
  line-height: 1.55;
}
.course-video-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px 20px;
}
.course-video-item {
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.35;
  padding: 11px 0;
  border-top: 1px solid rgba(108, 164, 255, 0.14);
}
.course-video-item a {
  color: var(--blue);
  white-space: nowrap;
}
.course-video-list a:hover { color: var(--blue); }
.ai4semi-page .page-title {
  font-size: clamp(1.85rem, 3.5vw, 3.4rem);
  max-width: 1120px;
}
.ai4semi-module {
  margin-top: 16px;
  padding-top: 12px;
}
.ai4semi-module .course-heading {
  margin-bottom: 8px;
}
.ai4semi-module .course-heading h2 {
  margin-bottom: 0;
  font-size: 1.08rem;
  line-height: 1.2;
}
.ai4semi-module .course-video-list {
  gap: 2px 20px;
}
.ai4semi-module .course-video-item {
  padding: 7px 0;
  border-top: 0;
}
@media (max-width: 980px) {
  .site-header {
    position: static;
    width: 80vw;
    transform: none;
    flex-direction: column;
    align-items: flex-start;
  }
  .nav { flex-wrap: wrap; gap: 16px 22px; }
  main { padding-top: 46px; }
  .cards-3, .cards-4, .two-col { grid-template-columns: 1fr; }
  .course-heading {
    align-items: flex-start;
    flex-direction: column;
  }
  .course-video-list { grid-template-columns: 1fr; }
}