/* ==========================================================================
   Layout — container, grids, section header, footer
   ========================================================================== */

.container {
  width: 100%;
  max-width: var(--cds-grid-max);
  margin-inline: auto;
  padding-inline: var(--cds-grid-gutter);
}

@media (min-width: 66rem) {
  .container {
    padding-inline: var(--cds-grid-gutter-lg);
  }
}

.page {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.page__main {
  flex: 1;
}

/* Vertical rhythm helper */
.stack > * + * {
  margin-top: var(--stack-gap, var(--cds-spacing-05));
}

/* Carbon-style card group: 1px gaps on a gray background read as grid lines */
.tile-grid {
  display: grid;
  gap: 1px;
  background: var(--cds-border-subtle);
  border: 1px solid var(--cds-border-subtle);
  grid-template-columns: 1fr;
}

@media (min-width: 42rem) {
  .tile-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 66rem) {
  .tile-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (min-width: 82rem) {
  .tile-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  /* Variant for sections with exactly three tiles (home topics) */
  .tile-grid--3 {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Section header: eyebrow + heading on the left, meta on the right */
.section-header {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--cds-spacing-03) var(--cds-spacing-05);
  padding-bottom: var(--cds-spacing-05);
  margin-bottom: var(--cds-spacing-05);
  border-bottom: 1px solid var(--cds-border-strong);
}

.section-header__eyebrow {
  display: block;
  margin-bottom: var(--cds-spacing-02);
  color: var(--cds-text-secondary);
}

/* Linkable sections: "#" link added by components/anchors.js */
.has-anchor {
  position: relative;
}

.anchor-link {
  margin-left: var(--cds-spacing-03);
  font-weight: 400;
  color: var(--cds-text-helper);
  text-decoration: none;
  opacity: 0;
  transition: opacity var(--cds-duration-fast) var(--cds-ease-productive);
}

.has-anchor:hover .anchor-link,
.anchor-link:focus-visible {
  opacity: 1;
}

.anchor-link:hover {
  color: var(--cds-link-primary);
  text-decoration: none;
}

@media (hover: none) {
  .anchor-link {
    opacity: 0.6;
  }
}

[id] {
  scroll-margin-top: var(--cds-spacing-06);
}

/* Footer */
.site-footer {
  margin-top: var(--cds-spacing-11);
  padding-block: var(--cds-spacing-06);
  border-top: 1px solid var(--cds-border-subtle);
  color: var(--cds-text-secondary);
}

.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--cds-spacing-03) var(--cds-spacing-06);
}

.site-footer a {
  color: inherit;
}

.site-footer__powered {
  letter-spacing: 0.02em;
}

.site-footer__sources {
  flex-basis: 100%;
}

.site-footer__sources a {
  text-decoration: underline;
}

.site-footer__nav {
  flex-basis: 100%;
}

.site-footer__nav a {
  text-decoration: underline;
  font-weight: 600;
}

.site-footer__powered strong {
  color: var(--cds-text-primary);
  font-weight: 600;
}

/* Per-page visitor count (core/item-views.js), appended to a lesson's or post's meta line. */
.item-views::before {
  content: "·";
  margin-inline: var(--cds-spacing-03);
}
.item-views[hidden] {
  display: none;
}

/* Reading comforts (js/core/ux.js) -------------------------------------------
   Reading progress, back-to-top and scroll reveal. Lives in layout.css because
   every page loads it. All motion is off with "reduce motion".
   (No cross-page view transition: these pages render their content with JS after
   navigation, so a fade would capture a blank page and look janky.) */

.ux-progress {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 9000;
  height: 3px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 200ms ease;
}
.ux-progress.is-on {
  opacity: 1;
}
.ux-progress > span {
  display: block;
  height: 100%;
  background: var(--cds-interactive);
  transform: scaleX(0);
  transform-origin: 0 50%;
}

.ux-top {
  position: fixed;
  right: max(16px, env(safe-area-inset-right));
  bottom: max(16px, env(safe-area-inset-bottom));
  z-index: 8000;
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  padding: 0;
  border: 1px solid var(--cds-border-subtle);
  background: var(--cds-layer, #fff);
  color: var(--cds-text-primary);
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 180ms ease, transform 180ms ease, visibility 180ms, background 120ms ease;
}
.ux-top.is-on {
  opacity: 1;
  visibility: visible;
  transform: none;
}
.ux-top:hover {
  background: var(--cds-interactive);
  border-color: var(--cds-interactive);
  color: #fff;
}
.ux-top:focus-visible {
  outline: 2px solid var(--cds-focus, #0f62fe);
  outline-offset: 2px;
}

/* Scroll reveal: only cards that start below the fold get this class. */
.ux-reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 420ms ease, transform 420ms cubic-bezier(0.2, 0.7, 0.2, 1);
}
.ux-reveal.is-in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .ux-progress,
  .ux-top,
  .ux-reveal {
    transition: none;
  }
  .ux-reveal {
    opacity: 1;
    transform: none;
  }
}

@media print {
  .ux-progress,
  .ux-top {
    display: none;
  }
}