.hero {
  padding-block: var(--space-6);
  background:
    radial-gradient(circle at 0% 0%, #ffffff 0, transparent 32%),
    linear-gradient(90deg, rgba(217, 226, 243, 0.82) 1px, transparent 1px),
    linear-gradient(rgba(217, 226, 243, 0.82) 1px, transparent 1px),
    #eef3ff;
  background-size: auto, 36px 36px, 36px 36px, auto;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.95fr);
  gap: var(--space-6);
  align-items: center;
}

.hero-copy {
  max-width: 650px;
}

.math-panel {
  min-height: 360px;
  position: relative;
  border: 1px solid var(--color-border);
  border-radius: 22px;
  background: rgba(255, 255, 255, 0.82);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.matrix-card {
  position: absolute;
  left: 8%;
  top: 14%;
  display: grid;
  gap: var(--space-1);
  padding: var(--space-4);
  border-left: 4px solid var(--color-primary);
  border-right: 4px solid var(--color-primary);
  background: var(--color-surface);
  box-shadow: var(--shadow-sm);
  color: var(--color-primary-dark);
  font-family: Consolas, monospace;
  font-size: 1.2rem;
}

.vector-plane {
  position: absolute;
  right: 9%;
  bottom: 13%;
  width: 210px;
  height: 180px;
  background-image:
    linear-gradient(var(--color-border) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-border) 1px, transparent 1px);
  background-size: 24px 24px;
}

.axis {
  position: absolute;
  background: var(--color-muted);
}

.axis-x {
  left: 0;
  right: 0;
  top: 50%;
  height: 1px;
}

.axis-y {
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
}

.vector {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 88px;
  height: 3px;
  transform-origin: left center;
  background: var(--color-accent);
}

.vector-a {
  transform: rotate(-32deg);
}

.vector-b {
  width: 70px;
  transform: rotate(48deg);
  background: var(--color-primary);
}

.page-hero {
  padding-block: var(--space-6);
  background: var(--color-surface-soft);
  border-bottom: 1px solid var(--color-border);
}

.center {
  text-align: center;
}

.timeline {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-4);
  padding: 0;
  list-style: none;
}

.timeline li {
  border-top: 3px solid var(--color-primary);
  padding-top: var(--space-3);
}

.timeline span {
  display: inline-grid;
  place-items: center;
  width: 30px;
  height: 30px;
  margin-bottom: var(--space-2);
  border-radius: 999px;
  background: var(--color-primary);
  color: #fff;
  font-weight: 800;
}

.cta-band {
  padding-block: var(--space-5);
  background: var(--color-primary-dark);
  color: #fff;
}

.cta-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.cta-band .eyebrow,
.cta-band h2 {
  color: #fff;
}

.tool-controls {
  margin-bottom: var(--space-5);
  padding: var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
}

.tool-controls label {
  display: block;
  margin-bottom: var(--space-2);
  font-weight: 800;
}

.tool-controls input {
  width: 100%;
  min-height: 46px;
  margin-bottom: var(--space-3);
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}

.filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.filter-button {
  min-height: 38px;
  padding: 0.45rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-muted);
}

.filter-button.is-active {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.category-stack {
  display: grid;
  gap: var(--space-6);
}

.tool-category[hidden],
.tool-card[hidden] {
  display: none;
}

.detail-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 360px;
  gap: var(--space-5);
  align-items: start;
}

.workspace-placeholder {
  min-height: 360px;
  padding: var(--space-5);
  display: grid;
  align-content: center;
  justify-items: start;
}

.placeholder-symbol {
  margin-bottom: var(--space-4);
  color: var(--color-primary);
  font-family: Consolas, monospace;
  font-size: 2.5rem;
  font-weight: 800;
}

.detail-panel {
  padding: var(--space-4);
}

.detail-panel dl {
  display: grid;
  gap: var(--space-3);
  margin: 0 0 var(--space-4);
}

.detail-panel dt {
  color: var(--color-muted);
  font-size: var(--font-sm);
}

.detail-panel dd {
  margin: 0;
  font-weight: 700;
}

.prose-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-4);
}

.prose-grid article {
  padding: var(--space-4);
  border-left: 3px solid var(--color-primary);
  background: var(--color-surface);
}

.wide-note {
  grid-column: 1 / -1;
}

@media (max-width: 860px) {
  .hero-grid,
  .detail-layout,
  .prose-grid {
    grid-template-columns: 1fr;
  }

  .math-panel {
    min-height: 300px;
  }

  .timeline {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .cta-inner {
    display: block;
  }
}

@media (max-width: 520px) {
  h1 {
    font-size: 1.9rem;
  }

  .hero,
  .page-hero,
  .section {
    padding-block: var(--space-5);
  }

  .timeline {
    grid-template-columns: 1fr;
  }

  .math-panel {
    min-height: 250px;
  }

  .matrix-card {
    left: 5%;
    top: 10%;
    font-size: 0.96rem;
  }

  .vector-plane {
    right: 5%;
    bottom: 10%;
    width: 160px;
    height: 140px;
  }
}