:root {
  --ch-ink: #1f2428;
  --ch-ink-muted: #4b5563;
  --ch-paper: #f7f5f1;
  --ch-sand: #ece6dd;
  --ch-accent: #2f5f6f;
  --ch-accent-soft: #e0edf2;
  --ch-border: #d9d2c8;
}

body {
  font-family: "Source Sans 3", "Segoe UI", Arial, sans-serif;
  color: var(--ch-ink);
  background: linear-gradient(180deg, #fbfaf8 0%, #f2efe9 50%, #f7f5f1 100%);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

h1, h2, h3, h4, h5 {
  font-family: "Source Serif 4", "Georgia", serif;
  letter-spacing: 0.2px;
}

.navbar {
  background: rgba(247, 245, 241, 0.96);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--ch-border);
}

.navbar-brand span {
  font-weight: 600;
  color: var(--ch-ink);
}

.nav-link {
  color: var(--ch-ink-muted);
}

.nav-link.active,
.nav-link:hover {
  color: var(--ch-ink);
}

.nav-link.active {
  border-bottom: 2px solid var(--ch-accent);
}

.hero {
  background: linear-gradient(rgba(20, 24, 28, 0.65), rgba(20, 24, 28, 0.45)),
    url("../resources/images/causal-humanism-banner.png") center/cover no-repeat;
  color: #f8fafc;
  border-radius: 24px;
  padding: 4rem 3rem;
  box-shadow: 0 24px 60px rgba(24, 32, 38, 0.2);
}

.hero .lead {
  color: rgba(248, 250, 252, 0.88);
}

.hero .btn-primary {
  background: var(--ch-accent);
  border-color: var(--ch-accent);
}

.hero .btn-outline-light {
  border-color: rgba(248, 250, 252, 0.7);
}

.section-card {
  border: 1px solid var(--ch-border);
  background: #fff;
  border-radius: 18px;
  box-shadow: 0 16px 40px rgba(31, 36, 40, 0.08);
}

.section-title {
  border-left: 4px solid var(--ch-accent);
  padding-left: 0.75rem;
}

.anchor-link {
  color: var(--ch-ink-muted);
  font-size: 0.85em;
  margin-left: 0.45rem;
  opacity: 0;
  position: relative;
  display: inline-block;
  text-decoration: none;
  transition: opacity 0.2s ease;
}

.anchor-link::after {
  background: var(--ch-ink);
  border-radius: 8px;
  color: #fff;
  content: attr(data-tooltip);
  font-size: 0.75rem;
  left: 50%;
  opacity: 0;
  padding: 0.25rem 0.5rem;
  position: absolute;
  top: -2.1rem;
  transform: translateX(-50%);
  transition: opacity 0.2s ease;
  white-space: nowrap;
}

h1:hover .anchor-link,
h2:hover .anchor-link,
h3:hover .anchor-link,
h4:hover .anchor-link,
.anchor-link:focus {
  opacity: 1;
}

.anchor-link:hover::after,
.anchor-link:focus::after,
.anchor-link.copied::after {
  opacity: 1;
}

blockquote {
  border-left: 4px solid var(--ch-accent);
  padding-left: 1rem;
  color: var(--ch-ink-muted);
  font-style: italic;
}

main {
  flex: 1 0 auto;
}

.timeline {
  border-left: 2px solid var(--ch-border);
  padding-left: 1.5rem;
}

.timeline-item {
  position: relative;
  margin-bottom: 1.5rem;
}

.timeline-item::before {
  content: "";
  position: absolute;
  left: -1.6rem;
  top: 0.35rem;
  width: 0.75rem;
  height: 0.75rem;
  background: var(--ch-accent);
  border-radius: 50%;
}

.diagram-loop {
  background: var(--ch-accent-soft);
  border: 1px dashed var(--ch-accent);
  border-radius: 14px;
  padding: 1.5rem;
  font-family: "Courier New", Courier, monospace;
  font-size: 0.95rem;
}

.flow-row {
  gap: 0.75rem;
}

.flow-box {
  border: 1px solid var(--ch-border);
  background: #fff;
  border-radius: 12px;
  padding: 0.75rem;
  min-width: 140px;
  text-align: center;
  box-shadow: 0 12px 28px rgba(31, 36, 40, 0.08);
}

.flow-arrow {
  font-weight: 600;
  color: var(--ch-accent);
  align-self: center;
}

.callout {
  background: var(--ch-sand);
  border-radius: 16px;
  padding: 1.5rem;
  border: 1px solid var(--ch-border);
}

section[id] {
  scroll-margin-top: 96px;
}

.footer {
  border-top: 1px solid var(--ch-border);
  background: #f2efe9;
  color: var(--ch-ink-muted);
  margin-top: auto;
}

.footer a {
  color: var(--ch-ink);
}

.badge-soft {
  background: var(--ch-accent-soft);
  color: var(--ch-accent);
  border: 1px solid rgba(47, 95, 111, 0.3);
}

@media (max-width: 768px) {
  .hero {
    padding: 3rem 1.75rem;
  }

  .nav-link.active {
    border-bottom: none;
    border-left: 3px solid var(--ch-accent);
    padding-left: 0.75rem;
  }
}