:root {
  color-scheme: light;
  --ink: #182625;
  --muted: #4f625f;
  --accent: #00564a;
  --line: #d2ded9;
  --paper: #fff;
  --wash: #edf4f0;
  --background: #f4f7f5;
  font: 100%/1.5 system-ui, sans-serif;
  color: var(--ink);
  background: var(--background);
}

* { box-sizing: border-box; }
body { margin: 0; }
a { color: var(--accent); }
button, input, select { font: inherit; }
:focus-visible { outline: 3px solid #006e70; outline-offset: 3px; }
h1, h2, h3, p { margin: 0; }
h1 { font-size: clamp(2rem, 4vw, 3.25rem); line-height: 1.07; letter-spacing: -.045em; }
h2 { font-size: clamp(1.35rem, 2vw, 2rem); line-height: 1.15; letter-spacing: -.025em; }
h3 { font-size: 1rem; line-height: 1.3; }
.wrap { width: min(100% - 2rem, 96rem); margin-inline: auto; }

.site-header { background: #123a34; color: white; }
.masthead { min-height: 3.5rem; display: flex; align-items: center; justify-content: space-between; gap: .75rem; }
.brand { color: white; text-decoration: none; font-size: 1.15rem; font-weight: 750; }
.brand span { color: #b5e3cf; }
.header-label { color: #d4eae2; font-size: .82rem; }

.intro { display: flex; justify-content: space-between; align-items: end; gap: 1.2rem; padding-block: 1.6rem; }
.intro h1 { margin-block: .2rem .45rem; }
.eyebrow { color: var(--accent); font-size: .72rem; font-weight: 800; letter-spacing: .09em; text-transform: uppercase; }
.intro p:not(.eyebrow), .summary { color: var(--muted); }
.guides { display: flex; flex-wrap: wrap; gap: .5rem; }
.guides a, .button {
  display: inline-block;
  border: 1px solid var(--line);
  border-radius: .5rem;
  background: var(--paper);
  color: var(--accent);
  padding: .5rem .75rem;
  text-decoration: none;
  font-size: .875rem;
  font-weight: 650;
  cursor: pointer;
}
.guides a[aria-current], .guides a:hover, .button:hover { background: var(--wash); }
.button.primary { background: var(--accent); color: white; }
.button.primary:hover { background: #074339; }

.workspace { display: grid; grid-template-columns: minmax(15rem, 21rem) minmax(0, 1fr); align-items: start; gap: .9rem; }
.catalogue, .plan { border: 1px solid var(--line); border-radius: .85rem; background: var(--paper); }
.catalogue-head { padding: 1rem; border-bottom: 1px solid var(--line); }
.catalogue h2 { font-size: 1.15rem; margin-bottom: .7rem; }
#filters { display: grid; gap: .3rem; }
#filters label { font-size: .82rem; font-weight: 700; }
#filters label:not(:first-child) { margin-top: .25rem; }
#filters input, #filters select { min-width: 0; width: 100%; padding: .45rem .6rem; border: 1px solid #a7bdb4; border-radius: .4rem; background: white; color: var(--ink); }
#count { color: var(--muted); font-size: .82rem; margin-top: .7rem; }
#lesson-list { max-height: clamp(16rem, calc(100dvh - 23rem), 46rem); overflow: auto; }
#lesson-list ul { list-style: none; padding: .35rem; margin: 0; }
#lesson-list a { display: block; border-radius: .45rem; padding: .45rem .6rem; color: var(--ink); text-decoration: none; font-weight: 650; font-size: .9rem; }
#lesson-list a:hover, #lesson-list a[aria-current] { background: var(--wash); color: var(--accent); }
#lesson-list a[aria-current] { box-shadow: inset 3px 0 var(--accent); }
#lesson-list small { display: block; color: var(--muted); font-weight: 400; }

.plan { padding: clamp(1rem, 2vw, 1.7rem); min-width: 0; scroll-margin-top: .8rem; }
.plan h2 { scroll-margin-top: 1rem; margin-block: .22rem .5rem; }
.plan-head { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: .2rem .8rem; align-items: start; border-bottom: 1px solid var(--line); padding-bottom: 1rem; margin-bottom: .85rem; }
.plan-head > :not(.actions) { grid-column: 1; }
.actions { grid-column: 2; grid-row: 1 / span 3; display: flex; flex-wrap: wrap; gap: .4rem; }
.plan-block { padding: .7rem 0; min-width: 0; overflow-wrap: anywhere; }
.plan-block h3 { margin-bottom: .38rem; }
.plan-block p { white-space: pre-line; }
.plan-block p + p, .plan-block pre, .plan-block pre + a { margin-top: .55rem; }
.plan-block a { display: inline-block; }
.teaching-steps { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .6rem; margin-block: .65rem; }
.teaching-steps .plan-block { border-radius: .5rem; background: var(--wash); padding: .7rem; }
.reasoning { color: var(--muted); }
.output-label { font-size: .8rem; font-weight: 700; }
pre { margin: 0; padding: .6rem .7rem; border-radius: .42rem; background: #152c28; color: #edf8f3; font-size: .82rem; white-space: pre-wrap; overflow-wrap: anywhere; }
.linked-list { margin: .35rem 0 0; padding-left: 1.2rem; }
.activity-list { margin-top: .6rem; border-top: 1px solid var(--line); padding-top: .7rem; }
.activity-list summary { cursor: pointer; font-weight: 700; }
.activity-list li + li { margin-top: .45rem; }
.footer { padding-block: 1rem; color: var(--muted); font-size: .82rem; }

@media (max-width: 65rem) {
  .plan-head { display: block; }
  .actions { margin-top: .65rem; }
  .teaching-steps { grid-template-columns: 1fr; }
}
@media (max-width: 48rem) {
  .wrap { width: calc(100% - 1rem); }
  .intro { align-items: start; flex-direction: column; padding-block: 1rem; }
  .workspace { grid-template-columns: minmax(0, 1fr); }
  #lesson-list { max-height: 13rem; }
}
@media print {
  :root { background: white; }
  .site-header, .intro, .catalogue, .actions, .footer { display: none; }
  .wrap { width: 100%; }
  .workspace, .plan-head { display: block; }
  .plan { border: 0; padding: 0; }
  .plan-block, pre { break-inside: avoid; }
  .teaching-steps { display: block; }
  .teaching-steps .plan-block, pre { color: black; background: white; }
  .teaching-steps .plan-block { padding-inline: 0; }
}