/* Giao diện màn chơi, các kiểu chơi, danh sách bài của môn và trang kết quả.
   Cỡ nội dung các khối (.blk) theo biến --u, mỗi nơi đặt --u riêng (đề bài to, ô đáp án nhỏ hơn). */

/* ================= Khối nội dung (.blk) ================= */
.blocks { display: inline-flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: .15em .5em; max-width: 100%; }
.blk { display: inline-flex; align-items: center; justify-content: center; max-width: 100%; }
.blk--text { font-size: var(--u, 3rem); font-weight: var(--fw-black); line-height: 1.1; white-space: nowrap; }
.blk--text.blk--word { font-size: calc(var(--u, 3rem) * .8); }
.blk--text.blk--word-long { font-size: calc(var(--u, 3rem) * .66); }
.blk--text.blk--long { font-size: calc(var(--u, 3rem) * .55); white-space: normal; text-align: center; }
.blk--label { font-size: calc(var(--u, 3rem) * .55); font-weight: var(--fw-black); line-height: 1.15; text-align: center; text-wrap: balance; }
.blk--icon { width: calc(var(--u, 3rem) * 1.5); }
.blk--icon svg, .blk__item svg { width: 100%; height: auto; }
.blk--icons { display: grid; grid-template-columns: repeat(var(--cols, 1), minmax(0, calc(var(--u, 3rem) * 1.35))); gap: .35rem; justify-content: center; }
.blk__item { display: block; width: 100%; }
.choice .blk--icons, .match__cell .blk--icons { width: 100%; }
.choice .blk--clock, .match__cell .blk--clock { width: 100%; max-width: 8.5rem; }
.blk--shape { width: calc(var(--u, 3rem) * 1.7); }
.blk--shape svg, .blk--clock svg { width: 100%; height: auto; }
.blk--clock { width: calc(var(--u, 3rem) * 3.2); }
.blk--blank { width: var(--u, 3rem); height: var(--u, 3rem); border: 4px dashed var(--c-ink-3); border-radius: var(--r-sm); }

/* ================= Màn chơi ================= */
.page.play {
  --u: clamp(2.75rem, 11vmin, 4.75rem);
  display: grid;
  grid-template-rows: auto 1fr auto;
  gap: var(--s-3);
  width: min(100%, 60rem);
  padding-bottom: 0;
}
.play__top { display: flex; align-items: center; gap: var(--s-3); min-height: var(--tap); }
.play__progress { flex: 1; min-width: 0; }
.play__dots { display: flex; gap: var(--s-2); margin: 0; padding: 0; list-style: none; }
.play__dot {
  flex: 1;
  max-width: 3.5rem;
  height: .875rem;
  border-radius: var(--r-pill);
  background: var(--c-line);
  transition: background-color var(--dur-2) linear, transform var(--dur-2) var(--ease-bounce);
}
.play__dot.is-done { background: var(--accent, var(--c-violet)); }
.play__dot.is-now { background: var(--accent-soft, var(--c-violet-soft)); box-shadow: inset 0 0 0 3px var(--accent, var(--c-violet)); transform: scaleY(1.25); }
.play__listen[hidden], .play [hidden] { display: none !important; }
.play__top > .btn:last-child:not(.play__listen) { margin-left: auto; }

.play__stage {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: var(--s-5);
  min-height: 0;
  padding-block: var(--s-2);
}
.play__intro { display: flex; flex-direction: column; align-items: center; gap: var(--s-4); }
.play__intro > .play__pal, .play__intro > .play__bubble { align-self: stretch; }

.play__pal { flex: none; width: 4.75rem; height: 4.75rem; border-radius: 50%; background: var(--c-sky-soft); justify-self: start; }
.play__pal svg { width: 100%; height: 100%; }

.play__bubble {
  position: relative;
  padding: var(--s-4) var(--s-5);
  border-radius: var(--r-md);
  background: var(--c-surface);
  box-shadow: 0 var(--edge) 0 var(--c-line);
  text-align: center;
}
.play__prompt { font-size: var(--fs-lg); line-height: 1.2; text-wrap: balance; }
.play__hint { margin-top: var(--s-2); font-size: var(--fs-sm); color: var(--c-ink-2); }
.play__show { --u: clamp(3rem, 14vmin, 5.5rem); display: flex; justify-content: center; padding-block: var(--s-1); }
.play__host { display: flex; justify-content: center; }
.play__host > * { width: 100%; }

/* Mobile dọc: nhân vật nằm cạnh khung lời nhắc. */
.play__intro { display: grid; grid-template-columns: auto 1fr; align-items: center; column-gap: var(--s-3); row-gap: var(--s-4); }
.play__show { grid-column: 1 / -1; }
.play__bubble::before {
  content: "";
  position: absolute;
  left: -.55rem; top: 50%;
  width: 1.1rem; height: 1.1rem;
  margin-top: -.55rem;
  background: var(--c-surface);
  border-radius: .25rem;
  transform: rotate(45deg);
}

/* ---- Thanh phản hồi và nút Tiếp tục ---- */
.play__feed {
  position: sticky;
  bottom: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-3);
  flex-wrap: wrap;
  min-height: 5.5rem;
  margin-inline: calc(var(--gutter) * -1);
  padding: var(--s-3) var(--gutter) calc(var(--safe-b) + var(--s-3));
  border-radius: var(--r-lg) var(--r-lg) 0 0;
  background: transparent;
  transition: background-color var(--dur-2) linear;
}
.play__feed--ok { background: var(--c-ok-soft); }
.play__feed--oops { background: var(--c-oops-soft); }
.play__msg { flex: 1 1 10rem; min-width: 0; font-size: var(--fs-lg); font-weight: var(--fw-black); line-height: 1.2; }
.play__next { flex: 1 1 12rem; max-width: 22rem; margin-left: auto; min-height: 4.25rem; }

/* Điện thoại nằm ngang / màn thấp: đề bài một bên, chỗ trả lời một bên. */
@media (orientation: landscape) and (max-height: 32rem) {
  .page.play { --u: clamp(2rem, 9vmin, 3.5rem); gap: var(--s-2); padding-top: calc(var(--safe-t) + var(--s-2)); }
  .play__stage { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr); align-items: center; gap: var(--s-5); }
  .play__intro { grid-template-columns: auto 1fr; }
  .play__show { --u: clamp(2.25rem, 10vmin, 3.75rem); }
  .play__feed { min-height: 4.25rem; padding-block: var(--s-2); }
  .play__next { min-height: 3.5rem; }
  .play__msg { font-size: var(--fs-md); }
  .numpad__keys { grid-template-columns: repeat(6, minmax(0, 1fr)); }
}

/* ================= Chọn đáp án ================= */
.choices { --u: clamp(2.5rem, 11vmin, 4.25rem); display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--s-4); width: 100%; }
.choices--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.choices--rows { grid-template-columns: minmax(0, 1fr); }
.choices--rows .choice { min-height: 0; padding-block: var(--s-3); }
.choices--rows .blk--icons { grid-template-columns: repeat(var(--cols, 1), minmax(0, calc(var(--u, 3rem) * .9))); }
.choices--4 .choice { min-height: clamp(5rem, 18vmin, 8rem); }
.choice {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: clamp(6rem, 24vmin, 9.5rem);
  padding: var(--s-3);
  border: 0;
  border-radius: var(--r-md);
  background: var(--c-surface);
  color: var(--c-ink);
  box-shadow: 0 var(--edge) 0 var(--accent, var(--c-violet));
  cursor: pointer;
  transition: transform var(--dur-1) var(--ease-out), box-shadow var(--dur-1) var(--ease-out), background-color var(--dur-2) linear, opacity var(--dur-2) linear;
}
.choice:active:not([disabled]) { transform: translateY(var(--edge)); box-shadow: 0 0 0 var(--accent, var(--c-violet)); }
.choice[disabled] { cursor: default; }
.choice--wrong { background: var(--c-oops-soft); box-shadow: 0 var(--edge) 0 var(--c-orange); opacity: .55; }
.choice--right { background: var(--c-ok-soft); box-shadow: 0 var(--edge) 0 var(--c-teal-deep); animation: pp-pop-in var(--dur-3) var(--ease-bounce) both; }
.choice--dim { opacity: .4; }
.choice__body { display: inline-flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: .1em .4em; }

/* ================= Đếm hình ================= */
.count { display: flex; flex-direction: column; align-items: center; gap: var(--s-4); width: 100%; }
.count__field { display: flex; flex-wrap: wrap; justify-content: center; gap: var(--s-4); width: 100%; padding: var(--s-4); border-radius: var(--r-md); background: var(--c-surface); box-shadow: 0 var(--edge) 0 var(--c-line); }
.count__group { --item: clamp(3rem, 12vmin, 5rem); display: grid; grid-template-columns: repeat(var(--cols, 5), minmax(0, var(--item))); gap: .35rem; justify-content: center; width: 100%; }
.count__item {
  position: relative;
  aspect-ratio: 1;
  padding: .2rem;
  border: 0;
  border-radius: var(--r-sm);
  background: transparent;
  cursor: pointer;
  transition: background-color var(--dur-1) linear, transform var(--dur-1) var(--ease-out);
}
.count__item .blk__item { width: 100%; }
.count__item:active:not([disabled]) { transform: scale(.92); }
.count__item.is-counted { background: var(--accent-soft, var(--c-sun-soft)); }
.count__item[disabled] { cursor: default; }
.count__badge {
  position: absolute; top: -.3rem; right: -.3rem;
  min-width: 1.6rem; height: 1.6rem; padding: 0 .3rem;
  display: grid; place-items: center;
  border-radius: var(--r-pill);
  background: var(--accent, var(--c-violet)); color: var(--accent-ink, #fff);
  font-size: .95rem; font-weight: var(--fw-black); line-height: 1;
}
.count__bar { display: flex; align-items: center; justify-content: center; gap: var(--s-4); width: 100%; }
.count__num { min-width: 4.5rem; padding: .1em .35em; border-radius: var(--r-md); background: var(--c-surface); box-shadow: 0 var(--edge) 0 var(--c-line); font-size: var(--fs-2xl); font-weight: var(--fw-black); line-height: 1.2; text-align: center; }
.count__done { flex: 1; max-width: 14rem; }

/* ================= Nhập số ================= */
.numpad { --u: clamp(2.5rem, 9vmin, 3.5rem); display: flex; flex-direction: column; align-items: center; gap: var(--s-3); width: min(100%, 22rem); margin-inline: auto; }
.numpad__display { width: 100%; padding: .1em .3em; border-radius: var(--r-md); background: var(--c-surface); box-shadow: 0 var(--edge) 0 var(--accent, var(--c-violet)); font-size: clamp(2.5rem, 9vmin, 3.75rem); font-weight: var(--fw-black); line-height: 1.25; text-align: center; letter-spacing: .08em; }
.numpad__display.is-empty { color: var(--c-ink-3); }
.numpad__keys { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: var(--s-2) var(--s-3); width: 100%; }
.numpad__key { width: 100%; min-height: clamp(3.25rem, 9vh, 4.5rem); padding: 0; border-radius: var(--r-md); font-size: var(--fs-xl); }
.numpad__key svg { width: 1.25em; height: 1.25em; }

/* ================= Điền chỗ trống / xếp thứ tự / ghép chữ ================= */
.slots { --u: clamp(2rem, 8vmin, 3.25rem); display: flex; flex-direction: column; align-items: center; gap: var(--s-5); width: 100%; }
.slots__row { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: var(--s-3); }
.slots__static { display: inline-flex; align-items: center; }
.slot {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 4.5rem; min-height: 4.5rem; padding: .25rem .5rem;
  border: 4px dashed var(--c-ink-3); border-radius: var(--r-sm);
  background: var(--accent-soft, var(--c-violet-soft)); color: var(--c-ink);
  cursor: pointer;
}
.slot[disabled] { cursor: default; }
.slot--filled { border-style: solid; border-color: var(--accent, var(--c-violet)); background: var(--c-surface); }
.slot--right { border-color: var(--c-teal-deep); background: var(--c-ok-soft); }
.slot--wrong { border-color: var(--c-orange); background: var(--c-oops-soft); }
.slot__ord { font-size: 1.75rem; font-weight: var(--fw-black); color: var(--c-ink-3); }
.slots--build .slots__row, .slots--build .tray { gap: var(--s-2); }
.slots--build .slot, .slots--build .tile { min-width: 3.5rem; padding-inline: .25rem; }
.tray { display: flex; flex-wrap: wrap; justify-content: center; gap: var(--s-3); }
.tile {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 4rem; min-height: 4.5rem; padding: .25rem .75rem;
  border: 0; border-radius: var(--r-sm);
  background: var(--c-surface); color: var(--c-ink);
  box-shadow: 0 var(--edge) 0 var(--accent, var(--c-violet));
  cursor: pointer;
  transition: transform var(--dur-1) var(--ease-out), box-shadow var(--dur-1) var(--ease-out), opacity var(--dur-2) linear;
}
.tile:active:not([disabled]) { transform: translateY(var(--edge)); box-shadow: 0 0 0 var(--accent, var(--c-violet)); }
.tile--used { opacity: .25; box-shadow: none; transform: translateY(var(--edge)); }
.tile[disabled] { cursor: default; }
.tile__body { display: inline-flex; align-items: center; gap: .1em .4em; }
.tile__body--stack { flex-direction: column; gap: .15rem; max-width: 7.5rem; }
.tile__body--stack .blk--icon { width: calc(var(--u) * 1.9); }
.tile__body--stack .blk--label { font-size: calc(var(--u) * .42); }
.tile__body--letter { font-size: var(--u); font-weight: var(--fw-black); line-height: 1.3; }

/* ================= Nối cặp ================= */
.match { --u: clamp(2rem, 8vmin, 3.25rem); display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--s-5); width: 100%; }
.match__col { display: flex; flex-direction: column; gap: var(--s-3); }
.match__cell {
  display: flex; align-items: center; justify-content: center;
  min-height: 4.75rem; padding: var(--s-2) var(--s-3);
  border: 4px solid transparent; border-radius: var(--r-md);
  background: var(--c-surface); color: var(--c-ink);
  box-shadow: 0 var(--edge) 0 var(--c-line);
  cursor: pointer;
  transition: transform var(--dur-1) var(--ease-out), background-color var(--dur-2) linear, border-color var(--dur-1) linear;
}
.match__cell.is-selected { border-color: var(--c-sky-deep); background: var(--c-sky-soft); transform: scale(1.03); }
.match__cell[disabled] { cursor: default; }
.match__cell.is-matched { opacity: 1; }
.match__body { display: inline-flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: .1em .4em; }
.pair--violet { background: var(--c-violet-soft); border-color: var(--c-violet); }
.pair--sky    { background: var(--c-sky-soft);    border-color: var(--c-sky-deep); }
.pair--coral  { background: var(--c-coral-soft);  border-color: var(--c-coral-deep); }
.pair--teal   { background: var(--c-teal-soft);   border-color: var(--c-teal-deep); }
.pair--orange { background: var(--c-orange-soft); border-color: var(--c-orange-deep); }

/* ================= Danh sách bài của một môn ================= */
.page.subject-page { width: min(100%, 48rem); }
.subject-page__badge { display: inline-flex; align-items: center; gap: var(--s-2); padding: .4rem 1rem; border-radius: var(--r-pill); background: var(--c-surface); font-size: var(--fs-md); font-weight: var(--fw-black); }
.subject-page__badge svg { width: 1.4rem; height: 1.4rem; color: var(--c-sun-deep); }
.subject-page__head { display: flex; align-items: center; justify-content: center; gap: var(--s-4); }
.subject-page__art { flex: none; width: 5rem; }
.subject-page__art svg { width: 100%; height: auto; }
.subject-page .seg { align-self: center; width: min(100%, 24rem); background: var(--c-surface); }
.subject-page .seg__btn[aria-pressed="true"] { background: var(--accent); color: var(--accent-ink); }

.unit { display: flex; flex-direction: column; gap: var(--s-4); padding: var(--s-4) var(--s-4) var(--s-5); border-radius: var(--r-lg); background: var(--c-surface); box-shadow: 0 var(--edge) 0 var(--c-line); }
.unit__head { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: var(--s-2); }
.unit__title { font-size: var(--fs-lg); }
.unit__age { padding: .15rem .8rem; border-radius: var(--r-pill); background: var(--accent-soft); font-size: var(--fs-sm); font-weight: var(--fw-black); }

.path { display: grid; grid-template-columns: repeat(auto-fill, minmax(5rem, 1fr)); gap: var(--s-4) var(--s-3); margin: 0; padding: 0; list-style: none; }
.path__item { display: flex; flex-direction: column; align-items: center; gap: var(--s-1); }
.node {
  position: relative;
  display: grid; place-items: center;
  width: 4.5rem; height: 4.5rem;
  padding: 0;
  border: 4px solid var(--accent);
  border-radius: 50%;
  background: var(--c-surface); color: var(--c-ink);
  box-shadow: 0 var(--edge) 0 var(--accent-deep);
  font-size: var(--fs-lg); font-weight: var(--fw-black);
  cursor: pointer;
  transition: transform var(--dur-1) var(--ease-out), box-shadow var(--dur-1) var(--ease-out);
}
.node:active { transform: translateY(var(--edge)); box-shadow: 0 0 0 var(--accent-deep); }
.node--done { background: var(--accent); color: var(--accent-ink); }
.node--next { border-color: var(--c-sun-deep); background: var(--c-sun); color: var(--c-ink); box-shadow: 0 var(--edge) 0 var(--c-sun-deep); }
.node--next:active { box-shadow: 0 0 0 var(--c-sun-deep); }
.node__ping { position: absolute; inset: -4px; border: 4px solid var(--c-sun-deep); border-radius: 50%; pointer-events: none; }
.node__stars { display: flex; gap: 1px; color: var(--c-ink-3); }
.node__stars svg { width: 1rem; height: 1rem; }
.node__stars .is-on { color: var(--c-sun-deep); }

/* ================= Trang kết quả ================= */
.page.reward { justify-content: center; gap: var(--s-3); }
.reward__pal { width: min(48vw, 10rem); }
.reward__pal svg { width: 100%; height: auto; }
.reward__title { font-size: var(--fs-3xl); line-height: 1; }
.reward__stars { display: flex; gap: var(--s-2); margin-block: var(--s-2); }
.reward__slot { position: relative; width: clamp(3.75rem, 20vw, 6rem); aspect-ratio: 1; }
.reward__star { position: absolute; inset: 0; width: 100%; height: 100%; }
.reward__star--empty { color: var(--c-ink-3); opacity: .45; }
.reward__star--full { color: var(--c-sun); opacity: 0; transform: scale(.3); filter: drop-shadow(0 5px 0 var(--c-sun-deep)); }
.reward__slot.is-on .reward__star--full { opacity: 1; transform: none; }
.reward__slot.is-new .reward__star--full { animation: pp-pop-in var(--dur-4) var(--ease-bounce) both; }
:root[data-motion="reduced"] .reward__slot.is-new .reward__star--full { animation: pp-fade-in 200ms linear both; }
.reward__spark { position: absolute; left: 50%; top: 50%; width: .7rem; height: .7rem; margin: -.35rem 0 0 -.35rem; border-radius: .2rem; background: var(--c-sun-deep); pointer-events: none; }
.reward__line { font-size: var(--fs-md); color: var(--c-ink); }
.reward__best, .reward__total { display: inline-flex; align-items: center; gap: var(--s-2); padding: .35rem 1rem; border-radius: var(--r-pill); font-size: var(--fs-md); font-weight: var(--fw-black); }
.reward__best { background: var(--c-coral); color: var(--c-ink); box-shadow: 0 4px 0 var(--c-coral-deep); }
.reward__total { background: var(--c-surface); box-shadow: 0 4px 0 var(--c-line); }
.reward__best svg, .reward__total svg { width: 1.3rem; height: 1.3rem; }
.reward__total svg { color: var(--c-sun-deep); }
.reward__actions { display: flex; flex-direction: column; gap: var(--s-3); width: min(100%, 22rem); margin-top: var(--s-3); }
.reward__actions .btn { width: 100%; }

/* Pháo giấy: lớp phủ cố định, không bắt chạm. */
.reward__confetti { position: fixed; inset: 0; z-index: var(--z-overlay); overflow: hidden; pointer-events: none; }
.reward__piece { position: absolute; top: 0; width: .6rem; height: 1rem; border-radius: .15rem; }
.reward__piece--dot { width: .75rem; height: .75rem; border-radius: 50%; }
.reward__piece--violet { background: var(--c-violet); }
.reward__piece--sky    { background: var(--c-sky); }
.reward__piece--sun    { background: var(--c-sun); }
.reward__piece--coral  { background: var(--c-coral); }
.reward__piece--orange { background: var(--c-orange); }
.reward__piece--teal   { background: var(--c-teal); }
.reward__piece--lime   { background: var(--c-lime); }

/* Màn thấp (điện thoại nằm ngang): nhân vật và chữ nhỏ lại để đủ chỗ. */
@media (orientation: landscape) and (max-height: 32rem) {
  .page.reward { gap: var(--s-2); padding-block: var(--s-2); }
  .reward__pal { width: 4.5rem; }
  .reward__line { display: none; }
  .reward__title { font-size: var(--fs-xl); }
  .reward__slot { width: 3.5rem; }
  .reward__actions { flex-direction: row; flex-wrap: wrap; justify-content: center; width: 100%; }
  .reward__actions .btn { width: auto; flex: 1 1 10rem; min-height: 3.5rem; font-size: var(--fs-md); }
  .reward__actions .btn--lg { min-height: 3.5rem; padding: 0 var(--s-5); font-size: var(--fs-md); }
}

/* ================= Lập trình: bàn cờ, ô chương trình, bảng lệnh ================= */
.board {
  --cell: var(--board-cell, max(2.5rem, min(4.5rem, calc((100vw - 3rem) / var(--cols)), calc((100dvh - 33rem) / var(--rows)))));
  position: relative;
  display: grid;
  grid-template-columns: repeat(var(--cols), var(--cell));
  grid-template-rows: repeat(var(--rows), var(--cell));
  width: max-content;
  max-width: 100%;
  margin-inline: auto;
  overflow: hidden;
  border-radius: var(--r-sm);
  box-shadow: 0 var(--edge) 0 var(--accent-deep, var(--c-sky-deep)), 0 0 0 4px var(--accent-deep, var(--c-sky-deep));
}
.board__cell { position: relative; display: block; width: var(--cell); height: var(--cell); }
.board__cell--a { background: var(--c-lime-soft); }
.board__cell--b { background: #fff; }
.board__item { position: absolute; inset: 12%; display: block; transition: opacity var(--dur-2) linear, transform var(--dur-2) var(--ease-bounce); }
.board__item svg { width: 100%; height: 100%; }
.board__goal { inset: 6%; }
.board__coin.is-got { opacity: 0; transform: scale(1.6); }
.board__bot {
  position: absolute; top: 0; left: 0; z-index: 2;
  width: var(--cell); height: var(--cell); padding: 0;
  transform: translate(calc(var(--x, 0) * var(--cell)), calc(var(--y, 0) * var(--cell)));
  transition: transform .4s var(--ease-out);
  pointer-events: none;
}
.board__face, .board__face svg { display: block; width: 100%; height: 100%; }
.board__face svg { transform: scale(1.2); }
.board__dir {
  position: absolute; right: 0; top: 0; display: grid; place-items: center;
  width: 36%; height: 36%; border-radius: 50%;
  background: var(--c-sun); color: var(--c-ink); box-shadow: 0 0 0 2px var(--c-ink);
  transform: rotate(var(--rot, 0deg));
  transition: transform .3s var(--ease-out);
}
.board__dir svg { width: 70%; height: 70%; }
.board__bot.is-bump { animation: prog-bump .35s var(--ease-out); }
@keyframes prog-bump { 0%, 100% { margin-left: 0; } 25% { margin-left: -.35rem; } 75% { margin-left: .35rem; } }
:root[data-motion="reduced"] .board__bot { transition: none; }
:root[data-motion="reduced"] .board__bot.is-bump { animation: none; outline: 3px solid var(--c-orange); outline-offset: -3px; border-radius: 50%; }
:root[data-motion="reduced"] .board__dir, :root[data-motion="reduced"] .board__item { transition: none; }

.blk--grid { --board-cell: calc(var(--u, 3rem) * .8); }
.blk--grid .board { margin: 0; }
.blocks:has(.blk--grid) { flex-direction: column; gap: var(--s-3); }

.prog { display: flex; flex-direction: column; align-items: center; gap: var(--s-4); width: 100%; }
.prog__code {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: var(--s-2);
  width: 100%; padding: var(--s-3);
  border-radius: var(--r-md); background: var(--accent-soft, var(--c-sky-soft));
}
.prog__slots { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: var(--s-2); }
.prog__loop {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: var(--s-2);
  padding: var(--s-2) var(--s-3); border-radius: var(--r-sm);
  background: #fff; box-shadow: 0 0 0 4px var(--c-sun-deep);
}
.prog__loophead, .prog-row--loop { display: inline-flex; align-items: center; gap: .25rem; font-weight: var(--fw-black); }
.prog__loophead svg, .prog-row__head svg { width: 2rem; height: 2rem; }
.prog__times { font-size: var(--fs-lg); line-height: 1; }

.pslot, .pchip, .pghost {
  --chip-bg: var(--c-sky); --chip-edge: var(--c-sky-deep);
  display: inline-grid; place-items: center; flex: none;
  width: clamp(3.25rem, 13.5vw, 4rem); height: clamp(3.25rem, 13.5vw, 4rem); padding: 0;
  border: 0; border-radius: var(--r-xs); color: var(--c-ink);
  touch-action: none; user-select: none; -webkit-user-select: none;
}
.pslot svg, .pchip svg, .pghost svg { width: 62%; height: 62%; transition: transform var(--dur-1) var(--ease-out); }
.opchip--turn { --chip-bg: var(--c-sun); --chip-edge: var(--c-sun-deep); }
.opchip--fwd { --chip-bg: var(--c-lime); --chip-edge: var(--c-lime-deep); }
.pslot { border: 4px dashed var(--c-ink-3); background: #fff; cursor: pointer; }
.pslot[disabled] { cursor: default; }
.pslot__n { font-size: 1.5rem; font-weight: var(--fw-black); color: var(--c-ink-3); }
.pslot--filled { border: 0; background: var(--chip-bg); box-shadow: 0 var(--edge) 0 var(--chip-edge); }
.pslot--locked { border: 0; background: var(--chip-bg, var(--c-sky)); box-shadow: 0 var(--edge) 0 var(--chip-edge, var(--c-sky-deep)); opacity: .85; cursor: default; }
.pslot--over { outline: 4px solid var(--c-violet); outline-offset: 2px; }
.pslot.is-lit { transform: translateY(-.35rem) scale(1.12); box-shadow: 0 .5rem 0 var(--chip-edge), 0 0 0 4px var(--c-ink); z-index: 1; }
.prog__palette { display: flex; flex-wrap: wrap; justify-content: center; gap: var(--s-3); }
.pchip { background: var(--chip-bg); box-shadow: 0 var(--edge) 0 var(--chip-edge); cursor: pointer; width: 4rem; height: 4rem; transition: transform var(--dur-1) var(--ease-out), box-shadow var(--dur-1) var(--ease-out); }
.pchip:active:not([disabled]) { transform: translateY(var(--edge)); box-shadow: 0 0 0 var(--chip-edge); }
.pchip[disabled] { cursor: default; opacity: .5; }
.pghost { position: fixed; left: 0; top: 0; z-index: 50; pointer-events: none; background: var(--chip-bg); box-shadow: 0 .5rem 0 var(--chip-edge); transform-origin: center; }
.prog--dragging .pslot:not(.pslot--locked) { border-color: var(--c-violet); }
.prog__actions { display: flex; align-items: center; justify-content: center; gap: var(--s-4); }
.prog__run { min-height: 4.5rem; padding-inline: var(--s-6); }
.prog__run svg { width: 1.25em; height: 1.25em; }
.prog--running .prog__code { opacity: .9; }

/* Chuỗi lệnh chỉ để xem (khối 'prog'). */
.blk--prog { display: inline-flex; align-items: center; gap: .5rem; max-width: 100%; }
.prog-row__ops { display: inline-flex; flex-wrap: wrap; justify-content: center; gap: .3rem; }
.prog-row__head { display: inline-flex; align-items: center; gap: .25rem; }
.prog-row--loop { flex-wrap: wrap; justify-content: center; }
.choice .opchip { width: 2.4rem; height: 2.4rem; }
.prog-row--loop { padding: .35rem .6rem; border-radius: var(--r-xs); background: #fff; box-shadow: 0 0 0 4px var(--c-sun-deep); }
.opchip { --chip-bg: var(--c-sky); --chip-edge: var(--c-sky-deep); display: inline-grid; place-items: center; width: calc(var(--u, 3rem) * .8); height: calc(var(--u, 3rem) * .8); border-radius: .6rem; background: var(--chip-bg); box-shadow: 0 .2rem 0 var(--chip-edge); color: var(--c-ink); }
.opchip svg { width: 64%; height: 64%; }
.opchip.opchip--turn, .pslot.opchip--turn, .pchip.opchip--turn, .pghost.opchip--turn { --chip-bg: var(--c-sun); --chip-edge: var(--c-sun-deep); }
.opchip.opchip--fwd, .pslot.opchip--fwd, .pchip.opchip--fwd, .pghost.opchip--fwd { --chip-bg: var(--c-lime); --chip-edge: var(--c-lime-deep); }
.board--nodir .board__dir { display: none; }
.choices--boards { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.choices--boards .blk--grid .board { --cell: min(3rem, calc(((100vw - 4rem) / 2 - 2rem) / var(--cols))); }
.choice .blk--prog { --u: 2.75rem; }

/* ================= STEM: mạch điện, cái cân, thước đo ================= */
.blk--circuit { width: min(100%, calc(var(--u, 3rem) * 4.6)); }
.blk--balance { width: min(100%, calc(var(--u, 3rem) * 6.4)); }
.blk--ruler { width: min(100%, calc(var(--u, 3rem) * 7.2)); }
.blk--circuit svg, .blk--balance svg, .blk--ruler svg { display: block; width: 100%; height: auto; }
.choices--boards .blk--circuit { width: 100%; }
.choice .blk--ruler { width: 100%; }
.tile .blk--ruler { width: 8.5rem; }