/* BKIG — Modern, clean, finance aesthetic */
:root {
  --color-bg-overlay: rgba(8, 12, 24, 0.75);
  --color-text: #ffffff;
  --color-text-muted: rgba(255, 255, 255, 0.88);
  --color-border: rgba(255, 255, 255, 0.35);
  --color-border-hover: rgba(255, 255, 255, 0.6);
  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  --header-height: 72px;
  --transition: 0.25s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-weight: 400;
  color: var(--color-text);
  background: #0a0e1a;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Hero */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--header-height) 1.5rem 2rem;
}

.hero-background {
  position: absolute;
  inset: 0;
  background-image: url('images/bkig_background.png');
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: var(--color-bg-overlay);
  z-index: 1;
}

/* Living Graph — Boston to Seoul chart */
.hero-chart {
  position: absolute;
  inset: 0;
  z-index: 2;
  opacity: 0.72;
  pointer-events: none;
}

.living-graph-svg {
  width: 100%;
  height: 100%;
  display: block;
}

.chart-line {
  stroke-dasharray: 1300;
  stroke-dashoffset: 1300;
  animation: chart-draw 2.4s ease-out forwards;
}

.chart-line-glow {
  stroke-dashoffset: 1300;
  animation: chart-draw 2.4s ease-out 0.15s forwards;
  opacity: 0.15;
}

.chart-line-main {
  stroke-dashoffset: 1300;
  animation: chart-draw 2.2s ease-out 0.08s forwards;
  opacity: 0.25;
}

@keyframes chart-draw {
  to {
    stroke-dashoffset: 0;
  }
}

.chart-node {
  fill: rgba(255, 255, 255, 0.95);
  opacity: 0;
  transform-origin: center;
  animation: node-appear 0.45s ease-out forwards, node-sparkle 2.2s ease-in-out 2.6s infinite;
}

.chart-node:nth-child(4) { animation-delay: 0.85s, 2.6s; }
.chart-node:nth-child(5) { animation-delay: 1.3s, 2.6s; }
.chart-node:nth-child(6) { animation-delay: 1.7s, 2.6s; }
.chart-node:nth-child(7) { animation-delay: 2.05s, 2.6s; }
.chart-node:nth-child(8) { animation-delay: 2.35s, 2.6s; }

@keyframes node-appear {
  to {
    opacity: 1;
  }
}

@keyframes node-sparkle {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

.hero-content {
  position: relative;
  z-index: 3;
  text-align: center;
  max-width: 720px;
}

.hero-title {
  margin: 0 0 0.75rem;
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--color-text);
}

.hero-subtitle {
  margin: 0 0 2rem;
  font-size: clamp(0.9375rem, 2vw, 1.125rem);
  font-weight: 400;
  color: var(--color-text-muted);
  letter-spacing: 0.01em;
}

.hero-cta {
  display: inline-block;
  padding: 0.875rem 2rem;
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text);
  text-decoration: none;
  border: 1.5px solid var(--color-border);
  border-radius: 6px;
  background: transparent;
  transition: border-color var(--transition), background var(--transition), color var(--transition);
}

.hero-cta:hover {
  border-color: var(--color-border-hover);
  background: rgba(255, 255, 255, 0.06);
}

/* Core Divisions — 핵심 활동 */
.core-divisions {
  background: #0f172a;
  padding: 4.5rem 2rem 5rem;
}

.core-divisions-inner {
  max-width: 1400px;
  margin: 0 auto;
}

.core-divisions-title {
  font-family: var(--font-sans);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin: 0 0 0.35em;
  text-align: center;
}

.core-divisions-sub {
  display: block;
  font-size: 0.65em;
  font-weight: 400;
  color: rgba(255, 255, 255, 0.6);
  letter-spacing: 0.02em;
}

.core-divisions-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
  margin-top: 2.5rem;
}

.core-divisions-card {
  background: rgba(15, 23, 42, 0.55);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 12px;
  padding: 1.75rem 1.5rem;
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.core-divisions-card:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 255, 255, 0.28);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.25);
}

.core-divisions-icon {
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 1rem;
  line-height: 0;
}

.core-divisions-card-title {
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--color-text);
  margin: 0 0 0.5rem;
}

.core-divisions-card-desc {
  font-size: 0.875rem;
  line-height: 1.55;
  color: rgba(255, 255, 255, 0.65);
  margin: 0 0 1.25rem;
  flex-grow: 1;
}

.core-divisions-link {
  font-size: 0.8125rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  transition: color var(--transition), gap var(--transition);
}

.core-divisions-link:hover {
  color: var(--color-text);
  gap: 0.5rem;
}

/* Participating Universities — 무한 마키 */
.participating-universities {
  background: #ffffff;
  padding: 10rem 0 12rem;
}

.participating-universities-title {
  font-family: var(--font-sans);
  font-size: clamp(1.75rem, 3.5vw, 2.25rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #0f172a;
  text-align: center;
  margin: 0 0 0.25rem;
}

.participating-universities .alumni-placement-sub {
  margin-bottom: 2.25rem;
}

.participating-universities .alumni-placement-sub:last-of-type {
  margin-top: 2.5rem;
  margin-bottom: 0;
}

.participating-universities-mask {
  overflow: hidden;
  width: 100%;
  -webkit-mask-image: linear-gradient(to right, transparent 0%, #000 10%, #000 90%, transparent 100%);
  mask-image: linear-gradient(to right, transparent 0%, #000 10%, #000 90%, transparent 100%);
}

.participating-universities-track {
  display: flex;
  width: max-content;
  animation: universities-marquee 40s linear infinite;
  will-change: transform;
  gap: 0;
}

.participating-universities-set {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3.5rem;
  flex-shrink: 0;
  padding: 0 2rem;
  min-width: fit-content;
}

.participating-universities-logo {
  flex-shrink: 0;
  width: 140px;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.participating-universities-logo img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center;
}

@keyframes universities-marquee {
  0% {
    transform: translate3d(0, 0, 0);
  }
  100% {
    transform: translate3d(-33.333%, 0, 0);
  }
}

/* Alumni Placement — 졸업생 진출 기업 (Minimal bordered grid) */
.alumni-placement {
  background: #ffffff;
  padding: 5rem 2rem 9rem;
}

.alumni-placement-inner {
  max-width: 1400px;
  margin: 0 auto;
}

.alumni-placement-title {
  font-family: var(--font-sans);
  font-size: clamp(1.75rem, 3.5vw, 2.25rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #0f172a;
  text-align: center;
  margin: 0 0 0.25rem;
}

.alumni-placement-sub {
  font-family: var(--font-sans);
  font-size: 1rem;
  color: #94a3b8;
  text-align: center;
  margin: 0 0 2.25rem;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

.alumni-placement-inner .alumni-placement-sub:last-of-type {
  margin-top: 2.5rem;
  margin-bottom: 0;
}

.alumni-placement-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 2.5rem 3rem;
}

.alumni-placement-item {
  display: flex;
  align-items: center;
  justify-content: center;
}

.alumni-placement-item img {
  width: 100%;
  max-width: 160px;
  height: 88px;
  object-fit: contain;
  object-position: center;
  transition: transform 0.25s ease;
}

.alumni-placement-item:hover img {
  transform: scale(1.05);
}

/* Join Us / Contact — Layered on slate-50 */
.join-contact {
  background: #f8fafc;
  padding: 5rem 2rem 6rem;
}

.join-contact-title {
  font-family: var(--font-sans);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: #334155;
  text-align: center;
  margin: 0 0 2.5rem;
}

.join-contact-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  max-width: 1100px;
  margin: 0 auto;
}

@media (min-width: 768px) {
  .join-contact-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

.join-contact-card {
  display: block;
  text-decoration: none;
  background: #ffffff;
  border: none;
  border-radius: 1rem;
  padding: 2rem 1.75rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  transition: background-color 0.3s ease, color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
}

.join-contact-card:hover {
  background: #0f172a;
  color: #ffffff;
  transform: translateY(-4px);
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
}

.join-contact-card:hover .join-contact-card-label,
.join-contact-card:hover .join-contact-card-title,
.join-contact-card:hover .join-contact-card-desc,
.join-contact-card:hover .join-contact-card-cta {
  color: #ffffff;
}

.join-contact-card:hover .join-contact-card-arrow {
  transform: translateX(4px);
}

.join-contact-card-inner {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  min-height: 200px;
}

.join-contact-card-label {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #64748b;
  margin-bottom: 0.5rem;
  transition: color 0.3s ease;
}

.join-contact-card-title {
  font-family: var(--font-sans);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: #0f172a;
  margin: 0 0 0.5rem;
  transition: color 0.3s ease;
}

.join-contact-card-desc {
  font-size: 0.9375rem;
  line-height: 1.55;
  color: #475569;
  margin: 0 0 auto;
  padding-bottom: 1rem;
  transition: color 0.3s ease;
}

.join-contact-card-cta {
  font-size: 0.875rem;
  font-weight: 600;
  color: #0f172a;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  transition: color 0.3s ease;
}

.join-contact-card-arrow {
  display: inline-block;
  transition: transform 0.3s ease;
}

/* Mobile */
@media (max-width: 900px) {
  .core-divisions-grid {
    grid-template-columns: 1fr;
    margin-top: 2rem;
  }

  .core-divisions {
    padding: 3.5rem 1.25rem 4rem;
  }

  .participating-universities {
    padding: 7rem 0 9rem;
  }

  .participating-universities-title {
    margin-bottom: 2.25rem;
  }

  .participating-universities-set {
    gap: 2rem;
    padding: 0 1.25rem;
  }

  .participating-universities-logo {
    width: 110px;
    height: 56px;
  }

  .alumni-placement {
    padding: 3.5rem 1.25rem 6rem;
  }

  .alumni-placement-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem 1.5rem;
  }

  .alumni-placement-item img {
    max-height: 56px;
    max-width: 140px;
  }

  .join-contact {
    padding: 3.5rem 1.25rem 4.5rem;
  }

  .join-contact-grid {
    grid-template-columns: 1fr;
  }
}