/* STEM — every tool on one page.
   Rows, not cards: an icon, a name and one line each. Fifteen of them in two
   columns fit on a laptop screen; as cards they took four pages. */

.stem {
  max-width: 64rem;
  margin: 0 auto;
  padding-bottom: 2rem;
}

.stem-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.3rem 1rem;
  margin: 0.4rem 0 1.1rem;
}

.stem-head h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  color: var(--color-coral);
}

.stem-head p { margin: 0; flex: 1; min-width: 14rem; color: var(--color-text-muted); }

/* Phone only: four jump links, since there the groups stack. */
.stem-jump { display: none; }

/* Two columns that fill top-to-bottom, so the reading order is the
   subject order and the columns come out nearly the same height. */
.stem-groups {
  columns: 2 26rem;
  column-gap: 1.2rem;
}

.stem-group {
  break-inside: avoid;
  margin: 0 0 1.2rem;
  border-radius: var(--radius);
  background: var(--color-bg-alt);
  box-shadow: var(--shadow-soft);
  overflow: hidden;
  scroll-margin-top: 5.5rem;     /* clear of the sticky site header */
}

.stem-group h2 {
  margin: 0;
  padding: 0.7rem 1rem;
  font-family: var(--font-display);
  font-size: 1.15rem;
  color: var(--color-text);
  border-bottom: 3px solid var(--stem-tint);
}

.stem-group h2 small { font-size: 0.8rem; font-weight: 600; color: var(--color-text-muted); }

.stem-group--math    { --stem-tint: var(--color-orange); --stem-wash: #fff3e6; }
.stem-group--science { --stem-tint: var(--color-sun);    --stem-wash: #fffbe3; }
.stem-group--code    { --stem-tint: var(--color-sky);    --stem-wash: #e8faf8; }
.stem-group--ai      { --stem-tint: var(--color-purple); --stem-wash: #f3effe; }

.stem-group ul { margin: 0; padding: 0.3rem; list-style: none; }

.stem-group li a {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  min-height: 3.4rem;
  padding: 0.5rem 0.7rem;
  border-radius: var(--radius-sm);
  color: inherit;
  text-decoration: none;
  transition: background 0.12s;
}

.stem-group li a:hover,
.stem-group li a:focus-visible { background: var(--stem-wash); outline: none; }
.stem-group li a:focus-visible { box-shadow: inset 0 0 0 2px var(--stem-tint); }

.stem-icon {
  flex: 0 0 2.4rem;
  height: 2.4rem;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: var(--stem-wash);
  font-size: 1.25rem;
  font-weight: 700;
}

.stem-text { display: grid; gap: 0.05rem; min-width: 0; }
.stem-text strong { font-family: var(--font-display); font-weight: 600; font-size: 1.02rem; }
.stem-text span { font-size: 0.86rem; line-height: 1.35; color: var(--color-text-muted); }

@media (max-width: 640px) {
  .stem-jump {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    width: 100%;
    margin-top: 0.4rem;
  }
  .stem-jump a {
    padding: 0.4rem 0.8rem;
    border-radius: 999px;
    background: var(--color-bg-alt);
    box-shadow: var(--shadow-soft);
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--color-text);
    text-decoration: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .stem-group li a { transition: none; }
}