* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: #f6f8fb;
  color: #1f2937;
  line-height: 1.6;
}

.container {
  width: min(1200px, 92%);
  margin: 0 auto;
}

.site-header {
  background: white;
  border-bottom: 1px solid #dbe3ee;
  padding: 2rem 0;
}

.eyebrow {
  margin: 0 0 0.5rem;
  font-size: 0.9rem;
  font-weight: 700;
  color: #4b5563;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 4vw, 3rem);
  line-height: 1.1;
}

.intro {
  max-width: 780px;
  margin-top: 0.75rem;
  color: #4b5563;
}

#searchInput {
  margin-top: 1rem;
  width: min(520px, 100%);
  padding: 0.9rem 1rem;
  border: 1px solid #cbd5e1;
  border-radius: 14px;
  font-size: 1rem;
}

.layout {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 1.5rem;
  padding: 1.5rem 0 2rem;
}

.sidebar,
.content-card,
.panel,
.nav-card {
  background: white;
  border: 1px solid #dbe3ee;
  border-radius: 20px;
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.05);
}

.sidebar {
  padding: 1rem;
  align-self: start;
  position: sticky;
  top: 1rem;
}

.sidebar h2 {
  margin-top: 0.25rem;
  font-size: 1.1rem;
}

.period-button {
  width: 100%;
  text-align: left;
  padding: 0.9rem 1rem;
  margin-bottom: 0.65rem;
  background: #fff;
  border: 1px solid #dbe3ee;
  border-radius: 16px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.period-button:hover {
  background: #f8fafc;
  border-color: #bac7d8;
}

.period-button.active {
  background: #111827;
  color: white;
  border-color: #111827;
}

.period-button small {
  display: block;
  opacity: 0.8;
  margin-top: 0.2rem;
}

.content {
  min-width: 0;
}

.content-card {
  overflow: hidden;
}

.hero {
  padding: 1.5rem;
  border-bottom: 1px solid #dbe3ee;
}

.badges {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.badge {
  display: inline-block;
  padding: 0.35rem 0.75rem;
  border: 1px solid #cbd5e1;
  border-radius: 999px;
  font-size: 0.85rem;
  background: #f8fafc;
}

.hero h2 {
  margin: 0;
  font-size: clamp(1.7rem, 3vw, 2.5rem);
}

.hero p {
  color: #4b5563;
  max-width: 820px;
}

.summary-grid,
.panel-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  padding: 1.25rem 1.5rem 1.5rem;
  background: #f8fafc;
}

.summary-box,
.panel {
  padding: 1rem;
}

.summary-box h3,
.panel h3,
.nav-card h3 {
  margin-top: 0;
}

.panel-grid {
  grid-template-columns: repeat(2, 1fr);
  background: transparent;
  padding: 1.5rem 0 0;
}

.panel ul {
  padding-left: 1.2rem;
  margin-bottom: 0;
}

.term-list,
.skill-list,
.quick-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
}

.chip {
  display: inline-block;
  background: #f8fafc;
  border: 1px solid #dbe3ee;
  border-radius: 999px;
  padding: 0.45rem 0.8rem;
  font-size: 0.95rem;
}

.nav-card {
  padding: 1.25rem 1.5rem;
  margin-top: 1.5rem;
}

.quick-nav button {
  border: 1px solid #cbd5e1;
  background: white;
  border-radius: 999px;
  padding: 0.55rem 0.9rem;
  cursor: pointer;
}

.quick-nav button.active {
  background: #111827;
  color: white;
  border-color: #111827;
}

.site-footer {
  padding: 1rem 0 2rem;
  color: #6b7280;
}

@media (max-width: 900px) {
  .layout,
  .summary-grid,
  .panel-grid {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }
}