/* ===== CSS Variables ===== */
:root {
  --primary: #2563EB;
  --primary-light: #3B82F6;
  --secondary: #7C3AED;
  --accent: #F59E0B;
  --bg: #F8FAFC;
  --dark: #0F172A;
  --gray-100: #F1F5F9;
  --gray-200: #E2E8F0;
  --gray-300: #CBD5E1;
  --gray-500: #64748B;
  --gray-700: #334155;
  --white: #FFFFFF;
  --font-main: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'Fira Code', 'Consolas', monospace;
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 4px 12px rgba(0,0,0,0.04);
  --shadow-lg: 0 4px 16px rgba(0,0,0,0.1), 0 8px 32px rgba(0,0,0,0.06);
  --transition: 0.2s ease;
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-main);
  background: var(--bg);
  color: var(--dark);
  line-height: 1.7;
  min-height: 100vh;
}
a { color: var(--primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--secondary); }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }
h1, h2, h3, h4 { line-height: 1.3; font-weight: 700; }
h1 { font-size: 2.5rem; }
h2 { font-size: 1.75rem; margin-bottom: var(--space-lg); }
h3 { font-size: 1.25rem; }
p { margin-bottom: var(--space-md); }

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* ===== Navigation ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--gray-200);
  z-index: 1000;
  padding: 0 var(--space-lg);
}
.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.navbar__logo {
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--primary);
}
.navbar__links {
  display: flex;
  gap: var(--space-lg);
}
.navbar__links a {
  color: var(--gray-700);
  font-weight: 500;
  font-size: 0.95rem;
  padding: var(--space-xs) 0;
  border-bottom: 2px solid transparent;
  transition: all var(--transition);
}
.navbar__links a:hover,
.navbar__links a.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}
.navbar__toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--dark);
}

/* ===== Hero Section ===== */
.hero {
  padding: 8rem 0 4rem;
  text-align: center;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  color: var(--white);
}
.hero h1 {
  font-size: 2.8rem;
  margin-bottom: var(--space-md);
}
.hero p {
  font-size: 1.2rem;
  opacity: 0.9;
  max-width: 640px;
  margin: 0 auto var(--space-xl);
}

/* ===== Section ===== */
.section {
  padding: var(--space-3xl) 0;
}
.section--alt {
  background: var(--white);
}
.section__title {
  text-align: center;
  margin-bottom: var(--space-2xl);
  position: relative;
}
.section__title::after {
  content: '';
  display: block;
  width: 48px;
  height: 4px;
  background: var(--accent);
  border-radius: 2px;
  margin: var(--space-sm) auto 0;
}

/* ===== Card Grid ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}
.card-grid--2 {
  grid-template-columns: repeat(2, 1fr);
}
.card {
  background: var(--white);
  border-radius: var(--radius);
  padding: var(--space-xl);
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
  border: 1px solid var(--gray-200);
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}
.card__icon {
  font-size: 2rem;
  margin-bottom: var(--space-md);
}
.card__title {
  margin-bottom: var(--space-sm);
  color: var(--dark);
}
.card__desc {
  color: var(--gray-500);
  font-size: 0.95rem;
}
.card__placeholder {
  background: var(--gray-100);
  border: 2px dashed var(--gray-300);
  border-radius: var(--radius-sm);
  height: 180px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--gray-500);
  font-size: 0.9rem;
  margin: var(--space-md) 0;
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 0.7rem 1.6rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
}
.btn--primary {
  background: var(--primary);
  color: var(--white);
}
.btn--primary:hover {
  background: var(--primary-light);
  color: var(--white);
}
.btn--outline {
  background: transparent;
  color: var(--white);
  border: 2px solid rgba(255,255,255,0.5);
}
.btn--outline:hover {
  background: rgba(255,255,255,0.15);
  color: var(--white);
}
.btn--accent {
  background: var(--accent);
  color: var(--dark);
}
.btn--accent:hover {
  background: #E8900A;
}
.btn-group {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
  justify-content: center;
  margin-top: var(--space-xl);
}

/* ===== Table ===== */
.table-wrap {
  overflow-x: auto;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
table {
  width: 100%;
  border-collapse: collapse;
  background: var(--white);
}
thead {
  background: var(--dark);
  color: var(--white);
}
th, td {
  padding: 0.85rem 1.2rem;
  text-align: left;
  font-size: 0.95rem;
}
tbody tr {
  border-bottom: 1px solid var(--gray-200);
}
tbody tr:hover {
  background: var(--gray-100);
}

/* ===== Timeline (Vertical) ===== */
.timeline {
  position: relative;
  padding: var(--space-xl) 0;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 24px;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--gray-200);
  border-radius: 2px;
}
.timeline__item {
  position: relative;
  padding-left: 60px;
  margin-bottom: var(--space-xl);
}
.timeline__dot {
  position: absolute;
  left: 16px;
  top: 4px;
  width: 18px;
  height: 18px;
  background: var(--primary);
  border: 3px solid var(--white);
  border-radius: 50%;
  box-shadow: 0 0 0 3px var(--primary);
}
.timeline__dot--secondary {
  background: var(--secondary);
  box-shadow: 0 0 0 3px var(--secondary);
}
.timeline__time {
  font-size: 0.85rem;
  color: var(--gray-500);
  font-weight: 600;
  margin-bottom: var(--space-xs);
}
.timeline__title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: var(--space-xs);
}
.timeline__desc {
  color: var(--gray-500);
  font-size: 0.93rem;
  margin-bottom: var(--space-sm);
}
.badge {
  display: inline-block;
  padding: 0.2rem 0.7rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
}
.badge--all { background: #DBEAFE; color: var(--primary); }
.badge--split { background: #EDE9FE; color: var(--secondary); }
.badge--team { background: #FEF3C7; color: #92400E; }

/* ===== Form / Embed Area ===== */
.embed-area {
  background: var(--white);
  border: 2px dashed var(--gray-300);
  border-radius: var(--radius);
  padding: var(--space-2xl);
  text-align: center;
  color: var(--gray-500);
}
.embed-area iframe {
  width: 100%;
  min-height: 500px;
  border: none;
  border-radius: var(--radius-sm);
}

/* ===== Footer ===== */
.footer {
  background: var(--dark);
  color: var(--gray-300);
  text-align: center;
  padding: var(--space-2xl) var(--space-lg);
  font-size: 0.9rem;
}
.footer__logo {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--white);
  margin-bottom: var(--space-sm);
}
.footer a { color: var(--accent); }

/* ===== Mobile Responsive ===== */
@media (max-width: 768px) {
  h1 { font-size: 1.8rem; }
  h2 { font-size: 1.35rem; }
  .hero { padding: 6rem 0 3rem; }
  .hero h1 { font-size: 2rem; }
  .hero p { font-size: 1rem; }

  .card-grid,
  .card-grid--2 {
    grid-template-columns: 1fr;
  }

  .navbar__links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--white);
    flex-direction: column;
    padding: var(--space-md) var(--space-lg);
    border-bottom: 1px solid var(--gray-200);
    box-shadow: var(--shadow);
  }
  .navbar__links.open {
    display: flex;
  }
  .navbar__toggle {
    display: block;
  }

  .timeline::before { left: 16px; }
  .timeline__item { padding-left: 48px; }
  .timeline__dot { left: 8px; }

  .btn-group { flex-direction: column; align-items: center; }
}