:root {
  color-scheme: dark;
  --bg: #070a12;
  --bg-elevated: #0d1323;
  --bg-soft: #11192b;
  --text: #f4f7fb;
  --muted: #a8b3c7;
  --subtle: #758199;
  --line: rgba(255, 255, 255, 0.12);
  --line-strong: rgba(255, 255, 255, 0.2);
  --accent: #78f0c9;
  --accent-2: #7aa7ff;
  --accent-3: #ffcf70;
  --danger: #ff8f8f;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.38);
  --radius: 8px;
  --max: 1180px;
}

:root[data-theme="light"] {
  color-scheme: light;
  --bg: #f7f8fb;
  --bg-elevated: #ffffff;
  --bg-soft: #edf1f7;
  --text: #101522;
  --muted: #4f5c71;
  --subtle: #69758a;
  --line: rgba(17, 24, 39, 0.13);
  --line-strong: rgba(17, 24, 39, 0.22);
  --accent: #087f62;
  --accent-2: #315ecf;
  --accent-3: #9b5a00;
  --danger: #a53333;
  --shadow: 0 24px 70px rgba(39, 52, 80, 0.16);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  overflow-x: hidden;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.5;
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -2;
  content: "";
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.04) 1px, transparent 1px);
  background-size: 72px 72px;
  mask-image: linear-gradient(to bottom, black, transparent 74%);
}

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

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

button,
a {
  -webkit-tap-highlight-color: transparent;
}

:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--accent) 70%, white);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  left: 1rem;
  top: 1rem;
  z-index: 20;
  padding: 0.75rem 1rem;
  transform: translateY(-180%);
  border-radius: var(--radius);
  background: var(--text);
  color: var(--bg);
  font-weight: 700;
}

.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:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(18px);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
}

.nav-shell,
.section-inner,
.hero-inner {
  width: min(calc(100% - 40px), var(--max));
  margin: 0 auto;
}

.nav-shell {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 82px;
  gap: 1rem;
}

.nav-actions,
.theme-toggle,
.social-links,
.card-actions,
.category-nav {
  display: flex;
  align-items: center;
}

.brand {
  display: inline-flex;
  align-items: center;
  min-height: 58px;
}

.brand img {
  display: block;
  width: auto;
  height: 60px;
  max-width: 160px;
  object-fit: contain;
}

.nav-actions {
  gap: 1rem;
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 650;
}

.theme-toggle {
  min-height: 44px;
  gap: 0.55rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.45rem 0.85rem;
  background: var(--bg-elevated);
  color: var(--text);
  cursor: pointer;
  font: inherit;
  font-weight: 700;
}

.toggle-icon {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-3), var(--accent));
  box-shadow: inset -5px -4px 0 color-mix(in srgb, var(--bg) 58%, transparent);
}

.hero {
  position: relative;
  min-height: auto;
  padding: 4.5rem 0 2.8rem;
  overflow: hidden;
}

.hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.22fr) minmax(360px, 0.78fr);
  align-items: center;
  gap: 2rem;
}

.hero-copy {
  max-width: 850px;
}

.eyebrow {
  margin: 0 0 1rem;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.hero .eyebrow {
  font-size: 0.95rem;
  letter-spacing: 0.18em;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  max-width: 950px;
  font-size: clamp(3.25rem, 7vw, 7.4rem);
  line-height: 0.95;
  letter-spacing: 0;
}

.subtitle {
  max-width: 690px;
  margin: 1.6rem 0 0;
  color: var(--muted);
  font-size: clamp(1.14rem, 2vw, 1.45rem);
}

.instructor-panel {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.95rem;
  align-items: center;
  max-width: 470px;
  justify-self: end;
  transform: translateY(-1.5rem);
  padding: 0.95rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--bg-elevated) 82%, transparent);
  box-shadow: var(--shadow);
}

.portrait {
  width: 126px;
  aspect-ratio: 1;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background: var(--bg-soft);
  object-fit: cover;
  object-position: center;
}

.panel-label {
  margin: 0;
  color: var(--accent-3);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

.instructor-panel h2 {
  margin: 0.15rem 0 0.2rem;
  font-size: 1.25rem;
}

.instructor-panel p:last-of-type {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.social-links {
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.75rem;
}

.social-icon-link,
.link-chip,
.status-chip {
  display: inline-flex;
  min-height: 34px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.4rem 0.7rem;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
}

.social-icon-link {
  width: 38px;
  min-height: 38px;
  padding: 0;
}

.social-icon-link svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

.social-icon-link[aria-label="Homepage"] svg {
  fill: none;
  stroke: currentColor;
  stroke-width: 2.2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.social-icon-link:hover,
.link-chip:hover {
  border-color: color-mix(in srgb, var(--accent) 55%, var(--line));
}

.section-band {
  border-block: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg-elevated) 42%, transparent);
}

.overview,
.journey,
.resources {
  padding: 4.5rem 0;
}

.overview-grid,
.resource-layout {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: clamp(2rem, 5vw, 5rem);
}

h2 {
  margin: 0;
  font-size: clamp(2rem, 4vw, 4rem);
  line-height: 1;
  letter-spacing: 0;
}

.overview-copy {
  display: grid;
  gap: 1rem;
  color: var(--muted);
  font-size: 1.05rem;
}

.overview-copy > p {
  margin-top: 0.15rem;
}

.overview-copy p,
.section-heading > p,
.overview-prereqs p {
  margin: 0;
}

.overview-prereqs {
  width: fit-content;
  max-width: min(100%, 840px);
  margin-top: 0.75rem;
  border: 1px solid color-mix(in srgb, var(--line) 72%, transparent);
  border-radius: var(--radius);
  padding: 0.8rem 0.9rem;
  background: color-mix(in srgb, var(--bg-soft) 58%, transparent);
  color: var(--subtle);
  font-size: 0.93rem;
  line-height: 1.45;
}

.overview-prereqs h3 {
  margin: 0 0 0.5rem;
  color: color-mix(in srgb, var(--text) 88%, var(--muted));
  font-size: 0.88rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.overview-prereqs p + p {
  margin-top: 0.55rem;
}

.section-heading {
  display: grid;
  grid-template-columns: 1fr minmax(240px, 0.42fr);
  gap: 2rem;
  align-items: end;
  margin-bottom: 1.45rem;
}

.section-heading > p {
  color: var(--muted);
  font-size: 1.05rem;
}

.category-nav {
  flex-wrap: wrap;
  gap: 0.55rem;
  margin-bottom: 0;
}

.category-button {
  min-height: 42px;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.6rem 0.85rem;
  background: color-mix(in srgb, var(--bg-soft) 72%, transparent);
  color: var(--muted);
  cursor: pointer;
  font: inherit;
  font-size: 0.85rem;
  font-weight: 800;
}

.category-button[aria-pressed="true"] {
  border-color: color-mix(in srgb, var(--accent) 65%, transparent);
  background: color-mix(in srgb, var(--accent) 14%, var(--bg-elevated));
  color: var(--text);
}

.lecture-note {
  margin: 1.75rem 0;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.5;
}

.lecture-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  align-items: start;
  gap: 1rem;
}

.lecture-card {
  position: relative;
  display: grid;
  gap: 1.05rem;
  align-content: start;
  padding: 1.25rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    linear-gradient(145deg, color-mix(in srgb, var(--bg-elevated) 92%, transparent), color-mix(in srgb, var(--bg-soft) 86%, transparent)),
    var(--bg-elevated);
  box-shadow: 0 18px 60px rgba(0, 0, 0, 0.22);
  transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
}

.lecture-card::before {
  position: absolute;
  inset: 0;
  pointer-events: none;
  content: "";
  border-radius: inherit;
  background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 18%, transparent), transparent 36%, color-mix(in srgb, var(--accent-2) 15%, transparent));
  opacity: 0;
  transition: opacity 180ms ease;
}

.lecture-card:hover {
  transform: translateY(-4px);
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  box-shadow: var(--shadow);
}

.lecture-card:hover::before {
  opacity: 1;
}

.card-top,
.card-bottom {
  position: relative;
  z-index: 1;
}

.card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.2rem;
  color: var(--subtle);
  font-size: 0.76rem;
  font-weight: 850;
  text-transform: uppercase;
}

.number {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  color: var(--accent);
}

.lecture-card h3 {
  margin: 0;
  font-size: clamp(1.26rem, 2vw, 1.65rem);
  line-height: 1.05;
  letter-spacing: 0;
}

.original-title {
  margin: 0.7rem 0 0;
  color: var(--accent-3);
  font-size: 0.9rem;
  font-weight: 800;
}

.description {
  margin: 1rem 0 0;
  color: var(--muted);
  font-size: 0.98rem;
}

.card-actions {
  flex-wrap: wrap;
  gap: 0.55rem;
}

.primary-cta {
  display: inline-flex;
  min-height: 42px;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0.65rem 0.95rem;
  background: var(--text);
  color: var(--bg);
  font-size: 0.86rem;
  font-weight: 850;
}

.primary-cta:hover {
  color: var(--bg);
  transform: translateY(-1px);
}

.status-chip {
  color: var(--subtle);
}

.gan-card {
  overflow: visible;
  transform-style: preserve-3d;
  transition: transform 620ms cubic-bezier(0.2, 0.8, 0.2, 1), border-color 220ms ease, box-shadow 220ms ease;
}

.gan-card.is-hover-revealed,
.gan-card.is-revealed {
  transform: perspective(1100px) rotateX(1deg) rotateY(-2deg) translateY(-3px);
}

.gan-reveal-slot {
  position: relative;
  height: 0;
  margin-top: 0;
  overflow: visible;
  transition:
    height 620ms cubic-bezier(0.2, 0.8, 0.2, 1),
    margin-top 620ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.gan-dialogue {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 5;
  display: grid;
  width: max-content;
  max-width: min(100%, 19rem);
  box-sizing: border-box;
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 0.62rem 0.72rem;
  background: color-mix(in srgb, var(--bg-elevated) 96%, transparent);
  box-shadow: 0 14px 34px rgba(0, 0, 0, 0.22);
  color: var(--muted);
  font-size: 0.8rem;
  line-height: 1.35;
  opacity: 0;
  pointer-events: none;
  transform: translate3d(0, 8px, -18px) rotateX(4deg);
  visibility: hidden;
  transition:
    transform 520ms cubic-bezier(0.2, 0.8, 0.2, 1),
    border-color 220ms ease;
}

.gan-dialogue p {
  margin: 0;
}

.gan-dialogue p + p {
  margin-top: 0.06rem;
}

.gan-dialogue p:nth-child(2n + 3) {
  margin-top: 0.42rem;
}

.gan-dialogue strong {
  color: var(--accent-3);
}

.gan-card.is-hover-revealed .gan-reveal-slot,
.gan-card.is-revealed .gan-reveal-slot {
  height: 9.4rem;
  margin-top: 0.75rem;
}

.gan-card.is-hover-revealed .gan-dialogue,
.gan-card.is-revealed .gan-dialogue {
  border-color: color-mix(in srgb, var(--accent) 18%, var(--line));
  opacity: 1;
  transform: translate3d(0, 0, 0) rotateX(0deg);
  visibility: visible;
}

.gan-card .card-top,
.gan-card .card-bottom {
  transition: transform 620ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.gan-card .card-bottom {
  z-index: 2;
}

.resource-columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.section-support {
  max-width: 520px;
  margin: 1rem 0 0;
  color: var(--muted);
  font-size: 1.02rem;
}

.resource-columns h3 {
  margin: 0 0 1rem;
  font-size: 1.05rem;
}

.resource-list {
  display: grid;
  gap: 0.8rem;
}

.resource-item {
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-elevated);
}

.resource-item strong {
  display: block;
  margin-bottom: 0.35rem;
}

.resource-item p {
  margin: 0 0 0.7rem;
  color: var(--muted);
}

.resource-group {
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}

.resource-group + .resource-group {
  margin-top: 1.25rem;
}

.resource-group h4 {
  margin: 0 0 0.65rem;
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 850;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.compact-resource-list {
  display: grid;
  gap: 0.35rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.resource-link {
  display: flex;
  min-height: 40px;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  border-radius: var(--radius);
  padding: 0.45rem 0.2rem;
  color: var(--muted);
  font-weight: 700;
}

.resource-link-text {
  display: grid;
  gap: 0.14rem;
  min-width: 0;
}

.resource-author {
  color: var(--subtle);
  font-size: 0.73rem;
  font-weight: 700;
  line-height: 1.35;
}

.resource-university {
  color: color-mix(in srgb, var(--subtle) 74%, transparent);
  font-size: 0.68rem;
  font-weight: 650;
  line-height: 1.3;
}

.resource-title {
  color: inherit;
  font-size: 0.94rem;
  line-height: 1.35;
}

.resource-course-code {
  color: var(--accent);
  font-weight: 850;
}

.course-link {
  align-items: start;
  padding-block: 0.55rem;
}

.course-link .resource-link-text {
  gap: 0.16rem;
}

.course-link .resource-title {
  margin-top: 0.08rem;
  color: var(--text);
  font-size: 0.98rem;
  font-weight: 780;
}

.resource-arrow {
  color: var(--subtle);
  font-weight: 850;
  flex: 0 0 auto;
  transition: transform 160ms ease, color 160ms ease;
}

.resource-link:hover {
  color: var(--text);
}

.resource-link:hover .resource-arrow {
  color: var(--accent);
  transform: translateX(3px);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition: none !important;
  }

  .gan-card.is-hover-revealed,
  .gan-card.is-revealed {
    transform: translateY(-2px);
  }

  .gan-dialogue {
    transform: none;
  }
}

@media (max-width: 1024px) {
  .hero {
    padding-top: 3.8rem;
  }

  .hero-inner,
  .overview-grid,
  .resource-layout,
  .section-heading {
    grid-template-columns: 1fr;
  }

  .instructor-panel {
    max-width: 560px;
    justify-self: start;
    transform: none;
  }

  .lecture-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .gan-dialogue {
    transform: translate3d(0, 8px, -16px);
  }

}

@media (max-width: 768px) {
  .nav-shell,
  .section-inner,
  .hero-inner {
    width: min(calc(100% - 28px), var(--max));
  }

  .nav-actions > a {
    display: none;
  }

  .hero {
    min-height: auto;
    padding: 2.8rem 0 1.8rem;
  }

  h1 {
    font-size: clamp(2.75rem, 11vw, 4.35rem);
  }

  .overview,
  .journey,
  .resources {
    padding: 3rem 0;
  }

  .overview-prereqs {
    width: 100%;
    max-width: none;
  }

  .lecture-grid,
  .resource-columns {
    grid-template-columns: 1fr;
  }

  .instructor-panel {
    grid-template-columns: auto 1fr;
    justify-items: start;
    max-width: none;
    justify-self: start;
    text-align: left;
    transform: none;
  }

  .portrait {
    width: 112px;
  }

  .social-links {
    justify-content: flex-start;
  }

  .category-nav {
    flex-wrap: wrap;
    overflow-x: visible;
    padding-bottom: 0;
  }

  .category-button {
    flex: 0 0 auto;
  }

  .card-actions {
    align-items: center;
    justify-content: flex-start;
  }

  .primary-cta,
  .link-chip,
  .status-chip {
    width: auto;
  }
}

@media (max-width: 380px) {
  .instructor-panel {
    grid-template-columns: 1fr;
  }

  .portrait {
    justify-self: start;
  }
}

@media (max-width: 430px) {
  .nav-shell {
    min-height: 68px;
  }

  .brand img {
    height: 48px;
  }

  .theme-toggle {
    padding-inline: 0.68rem;
  }

  .toggle-text {
    display: none;
  }

  .hero {
    padding-top: 2.25rem;
  }
}