/* TỨ PHỦ — About / Digital Heritage Manifesto */

.ab-hero {
  position: relative;
  overflow: hidden;
}

.ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 55% 45% at 12% 18%, rgba(196, 154, 89, 0.14), transparent 55%),
    radial-gradient(ellipse 42% 40% at 92% 78%, rgba(116, 43, 50, 0.2), transparent 52%);
  pointer-events: none;
}

.ab-rule {
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(196, 154, 89, 0.55), transparent);
}

.ab-sticky-nav {
  position: sticky;
  top: var(--header-h, 64px);
  z-index: 40;
  border-bottom: 1px solid rgba(98, 68, 60, 0.45);
  background: rgba(25, 15, 18, 0.92);
  backdrop-filter: blur(10px);
}

.ab-sticky-nav-inner {
  display: flex;
  gap: 0.25rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  padding: 0.55rem 0;
}

.ab-sticky-nav a {
  flex-shrink: 0;
  border-radius: 999px;
  border: 1px solid transparent;
  padding: 0.35rem 0.75rem;
  font-size: 0.78rem;
  color: #d5ba99;
  text-decoration: none;
  white-space: nowrap;
}

.ab-sticky-nav a:hover,
.ab-sticky-nav a:focus-visible,
.ab-sticky-nav a.is-active {
  border-color: rgba(196, 154, 89, 0.55);
  color: #f4e6d1;
  outline: none;
}

.ab-sticky-nav a.is-active {
  background: rgba(116, 43, 50, 0.4);
}

.ab-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  min-height: 2.5rem;
  border-radius: 0.65rem;
  border: 1px solid rgba(98, 68, 60, 0.55);
  background: rgba(53, 35, 38, 0.9);
  color: #f4e6d1;
  padding: 0.45rem 0.9rem;
  font-size: 0.875rem;
  font-weight: 500;
}

.ab-btn:hover,
.ab-btn:focus-visible {
  border-color: #c49a59;
  outline: none;
}

.ab-btn.is-primary {
  border-color: transparent;
  background: #742b32;
}

.ab-btn.is-primary:hover,
.ab-btn.is-primary:focus-visible {
  background: #913c43;
}

.ab-card {
  border-radius: 0.85rem;
  border: 1px solid rgba(98, 68, 60, 0.55);
  background: rgba(42, 26, 28, 0.88);
  padding: 1.1rem;
  color: inherit;
  text-align: left;
}

.ab-card:hover,
.ab-card:focus-within {
  border-color: #c49a59;
}

.ab-card-grid {
  display: grid;
  gap: 0.85rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .ab-card-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1024px) {
  .ab-card-grid.is-3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .ab-card-grid.is-4 {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.ab-paper {
  border-radius: 0.85rem;
  border: 1px solid rgba(98, 68, 60, 0.28);
  background: #f5ebdd;
  color: #33241f;
  padding: 1.35rem 1.2rem;
}

.ab-keyword {
  display: inline-flex;
  border-radius: 999px;
  border: 1px solid rgba(196, 154, 89, 0.4);
  padding: 0.25rem 0.7rem;
  font-size: 0.75rem;
  color: #e4c58c;
}

.ab-order {
  font-family: "Noto Serif", Georgia, serif;
  font-size: 1.5rem;
  color: #c49a59;
  line-height: 1;
}

.ab-graph-wrap {
  border-radius: 0.85rem;
  border: 1px solid rgba(98, 68, 60, 0.55);
  background: rgba(42, 26, 28, 0.75);
  padding: 1rem;
  overflow: auto;
}

.ab-graph-svg {
  display: none;
  width: 100%;
  min-width: 640px;
  height: auto;
}

@media (min-width: 768px) {
  .ab-graph-svg {
    display: block;
  }

  .ab-graph-flow {
    display: none;
  }
}

.ab-graph-node {
  cursor: pointer;
}

.ab-graph-node rect {
  fill: rgba(53, 35, 38, 0.95);
  stroke: rgba(98, 68, 60, 0.7);
  stroke-width: 1;
}

.ab-graph-node text {
  fill: #f4e6d1;
  font-size: 12px;
  font-family: "Be Vietnam Pro", system-ui, sans-serif;
}

.ab-graph-node:hover rect,
.ab-graph-node.is-active rect,
.ab-graph-node:focus rect {
  stroke: #c49a59;
  stroke-width: 1.5;
}

.ab-graph-edge {
  stroke: rgba(196, 154, 89, 0.35);
  stroke-width: 1.5;
  fill: none;
}

.ab-graph-edge.is-active {
  stroke: #c49a59;
  stroke-width: 2;
}

.ab-graph-flow {
  display: grid;
  gap: 0.65rem;
}

.ab-flow-item {
  position: relative;
  padding-left: 1.25rem;
}

.ab-flow-item::before {
  content: "";
  position: absolute;
  left: 0.35rem;
  top: 0.55rem;
  bottom: -0.65rem;
  width: 1px;
  background: rgba(196, 154, 89, 0.35);
}

.ab-flow-item:last-child::before {
  display: none;
}

.ab-flow-dot {
  position: absolute;
  left: 0;
  top: 0.55rem;
  width: 0.65rem;
  height: 0.65rem;
  border-radius: 999px;
  background: #c49a59;
}

.ab-timeline {
  display: grid;
  gap: 1rem;
}

@media (min-width: 1024px) {
  .ab-timeline {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.ab-phase {
  border-radius: 0.85rem;
  border: 1px solid rgba(98, 68, 60, 0.55);
  background: rgba(42, 26, 28, 0.88);
  padding: 1rem;
}

.ab-phase-status {
  display: inline-flex;
  border-radius: 999px;
  border: 1px solid rgba(98, 68, 60, 0.55);
  padding: 0.1rem 0.5rem;
  font-size: 0.65rem;
  color: #d5ba99;
}

.ab-phase-status.is-progress {
  border-color: #c49a59;
  color: #e4c58c;
}

.ab-tech-cols {
  display: grid;
  gap: 0.85rem;
}

@media (min-width: 768px) {
  .ab-tech-cols {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.ab-note {
  font-size: 0.8rem;
  color: #d5ba99;
}

.ab-quote {
  border-left: 3px solid #c49a59;
  padding-left: 1rem;
}

@media (prefers-reduced-motion: reduce) {
  .ab-sticky-nav {
    backdrop-filter: none;
  }
}