@import url('/gcsephy/assets/fonts/archivo-black.css');

/* Do Now starters. Layout and type follow the gcsephy companion sites and
   decks (Arial Black headings, 2px ink borders, hard shadows) with its own
   palette: a deep teal board, marigold accent and pink action buttons. */
:root {
  --board: #0c3a3f;
  --board-deep: #072a2e;
  --paper: #f8f5ec;
  --ink: #0b2a2e;
  --muted: #4f6163;
  --hi: #ffc145;
  --pop: #ff8fa3;
  --soft: #c4d8d6;
  --violet: #a895ff;
  --line: rgba(11, 42, 46, .17);
  --card: #fffdf7;
  --answer: #d9f2ee;
  --answer-edge: #0f7f78;
  --display: "Arial Black", "Archivo Black", Arial, sans-serif;
  --grid: linear-gradient(rgba(140, 214, 204, .11) 1px, transparent 1px), linear-gradient(90deg, rgba(140, 214, 204, .11) 1px, transparent 1px);
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 16px/1.45 Arial, Helvetica, sans-serif; }
button, input { font: inherit; color: inherit; }
button { cursor: pointer; -webkit-tap-highlight-color: transparent; }
button:focus-visible, a:focus-visible, input:focus-visible, .topic input:focus-visible + span { outline: 3px solid var(--pop); outline-offset: 3px; }

/* ---------- Setup ---------- */
.topbar {
  min-height: 64px; padding: 0 clamp(16px, 5vw, 64px); display: flex; align-items: center; justify-content: space-between; gap: 16px;
  background: var(--board-deep); color: #fff; border-bottom: 1px solid rgba(255, 255, 255, .15);
}
.brand { display: inline-flex; align-items: center; gap: 4px; min-height: 48px; font-weight: 800; letter-spacing: -.02em; }
.brand a { display: inline-flex; align-items: center; min-height: 48px; color: inherit; text-decoration: none; }
.brand-logo { justify-content: center; min-width: 48px; margin-left: -8px; }
.brand-name { padding: 0 8px 0 0; }
.topbar-links { display: flex; gap: 8px; }
.topbar-link { display: inline-flex; align-items: center; min-height: 48px; padding: 0 16px; border: 1px solid rgba(255, 255, 255, .4); border-radius: 999px; color: #fff; font-size: 14px; font-weight: 800; text-decoration: none; white-space: nowrap; }
.topbar-link:hover { background: #fff; color: var(--board); }
@media (max-width: 480px) {
  .topbar { gap: 8px; }
  .brand { gap: 0; white-space: nowrap; }
  .topbar-links { gap: 6px; }
  .topbar-link { padding: 0 11px; font-size: 13px; }
}
@media (max-width: 360px) {
  .topbar .brand-name { display: none; }
}

.hero { background-color: var(--board); background-image: var(--grid); background-size: 58px 58px; color: #fff; padding: clamp(28px, 5vw, 56px) clamp(16px, 5vw, 64px) clamp(44px, 6vw, 72px); }
.hero-inner { max-width: 1180px; margin: 0 auto; }
.eyebrow { margin: 0 0 14px; font-size: 12px; font-weight: 900; letter-spacing: .18em; text-transform: uppercase; }
.eyebrow span { color: var(--hi); }
.hero h1 { margin: 0; font: 900 clamp(56px, 11vw, 132px)/.82 var(--display); letter-spacing: -.07em; text-transform: uppercase; }
.hero h1 em { font-style: normal; color: var(--hi); }
.lead { margin: 22px 0 0; max-width: 620px; font-size: clamp(17px, 2vw, 21px); color: #dcebe9; }

.setup-main { max-width: none; padding: 0 max(clamp(16px, 5vw, 64px), calc((100% - 1180px) / 2)) 24px; margin-top: -28px; display: grid; gap: 26px; }
.panel { background: var(--card); border: 2px solid var(--ink); border-radius: 12px; box-shadow: 6px 6px 0 var(--pop); padding: clamp(16px, 2.5vw, 28px); }
.panel + .panel { box-shadow: 6px 6px 0 var(--hi); }
.panel-head { display: flex; align-items: center; justify-content: space-between; gap: 14px; flex-wrap: wrap; margin-bottom: 16px; }
.panel h2 { margin: 0; display: flex; align-items: center; gap: 12px; font: 900 clamp(22px, 3vw, 30px)/1 var(--display); letter-spacing: -.04em; text-transform: uppercase; }
.panel h2 b { display: grid; place-items: center; width: 40px; height: 40px; border: 2px solid var(--ink); border-radius: 50%; background: var(--hi); font-size: 20px; letter-spacing: 0; }

.switches { display: flex; flex-wrap: wrap; gap: 10px; }
.segmented { display: inline-flex; border: 2px solid var(--ink); border-radius: 999px; overflow: hidden; background: #fff; }
.segmented button { min-height: 48px; padding: 0 16px; border: 0; background: none; font-size: 14px; font-weight: 800; }
.segmented button[aria-pressed="true"] { background: var(--ink); color: #fff; }

.search-row { display: flex; gap: 10px; flex-wrap: wrap; }
.search { flex: 1 1 280px; display: flex; align-items: center; gap: 10px; min-height: 52px; padding: 0 16px; border: 2px solid var(--ink); border-radius: 10px; background: #fff; }
.search svg { width: 22px; height: 22px; flex: none; fill: none; stroke: var(--muted); stroke-width: 2.4; stroke-linecap: round; }
.search input { flex: 1; min-width: 0; height: 48px; border: 0; background: none; font-size: 17px; outline: none; }
.search:focus-within { outline: 3px solid var(--pop); outline-offset: 2px; }
.ghost { min-height: 52px; padding: 0 16px; border: 2px solid var(--ink); border-radius: 10px; background: #fff; font-weight: 800; font-size: 14px; }
.ghost:hover, .presets button:hover, .unit-all:hover { background: var(--ink); color: #fff; }
.hint { margin: 12px 0 0; font-size: 13.5px; color: var(--muted); }
.hint.first { margin: 0 0 14px; font-size: 15px; }
.badge-s { display: inline-block; padding: 1px 7px; border: 1.5px solid var(--ink); border-radius: 999px; background: var(--violet); color: var(--ink); font-size: 11px; font-weight: 900; letter-spacing: .04em; white-space: nowrap; }

/* Everything currently ticked, shown even when its unit is folded away. */
.chosen { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin-top: 14px; padding: 10px 12px; border: 2px solid var(--ink); border-radius: 10px; background: #fff6de; }
.chosen-label { font-size: 12px; font-weight: 900; letter-spacing: .12em; text-transform: uppercase; }
.chip { display: inline-flex; align-items: center; gap: 8px; min-height: 48px; padding: 0 8px 0 14px; border: 2px solid var(--ink); border-radius: 999px; background: var(--hi); font-size: 14px; font-weight: 800; text-align: left; }
.chip.practical { background: var(--pop); }
.chip:hover { background: var(--ink); color: #fff; }
.chip svg { flex: none; width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 3; stroke-linecap: round; }
.units { margin-top: 8px; }
.loading, .empty { padding: 22px 0 6px; color: var(--muted); font-weight: 700; }
.unit { padding-top: 20px; }
.unit-head { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin-bottom: 10px; padding-bottom: 8px; border-bottom: 2px solid var(--ink); }
.unit-head h3 { margin: 0; }
.unit-toggle { display: inline-flex; align-items: center; gap: 8px; min-height: 48px; padding: 0 8px 0 0; border: 0; background: none; font: 900 18px/1.1 var(--display); letter-spacing: -.03em; text-transform: uppercase; text-align: left; }
.unit-toggle svg { flex: none; width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 3; stroke-linecap: round; stroke-linejoin: round; transition: transform .15s ease; }
.unit-toggle[aria-expanded="false"] svg { transform: rotate(-90deg); }
.unit-paper.has-selection { color: var(--ink); }
.unit:has(.unit-toggle[aria-expanded="false"]) { padding-top: 8px; }
.unit:has(.unit-toggle[aria-expanded="false"]) .unit-head { margin-bottom: 0; }
.unit-paper { font-size: 11px; font-weight: 900; letter-spacing: .14em; text-transform: uppercase; color: var(--muted); }
.unit-all { margin-left: auto; min-height: 48px; padding: 0 14px; border: 2px solid var(--ink); border-radius: 999px; background: #fff; font-size: 13px; font-weight: 800; }
/* Working scientifically (above the content units) and Required practicals
   (below them) are set apart in their own bordered blocks. */
.methods-block, .unit.skills-block { padding: 6px 16px 16px; border: 2px dashed var(--ink); border-radius: 12px; background: #e6f4f1; }
.methods-block { margin-top: 34px; }
.unit.skills-block { margin: 20px 0 14px; }
.methods-block .unit-head, .skills-block .unit-head { margin-bottom: 10px; }
.methods-block:has(.unit-toggle[aria-expanded="false"]), .unit.skills-block:has(.unit-toggle[aria-expanded="false"]) { padding-top: 6px; padding-bottom: 6px; }
.methods-block:has(.unit-toggle[aria-expanded="false"]) .unit-head, .skills-block:has(.unit-toggle[aria-expanded="false"]) .unit-head { margin-bottom: 0; border-bottom: 0; }
.topics { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 290px), 1fr)); gap: 8px; }
.topic { position: relative; display: block; }
.topic input { position: absolute; opacity: 0; width: 100%; height: 100%; margin: 0; cursor: pointer; }
.topic > span { display: flex; align-items: center; gap: 10px; min-height: 52px; height: 100%; padding: 8px 12px; border: 2px solid var(--line); border-radius: 10px; background: #fff; font-size: 15px; font-weight: 700; line-height: 1.25; }
.topic > span::before { content: ""; flex: none; width: 22px; height: 22px; border: 2px solid var(--ink); border-radius: 6px; background: #fff; }
.topic:hover > span { border-color: var(--ink); }
.topic input:checked + span { border-color: var(--ink); background: var(--hi); }
.topic input:checked + span::before { background: var(--ink) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23ffc145' stroke-width='4' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M5 12.5l4.5 4.5L19 7.5'/%3E%3C/svg%3E") center/16px no-repeat; }
.topic-name { flex: 1; }
.topic-match { display: block; margin-top: 2px; font-size: 12.5px; font-weight: 600; color: var(--muted); }
.topic-count { flex: none; font: 700 12.5px/1 ui-monospace, Menlo, Consolas, monospace; color: var(--muted); }
.topic input:checked + span .topic-count { color: var(--ink); }

.picker { margin-top: 12px; max-height: min(70vh, 720px); overflow: auto; border: 2px solid var(--line); border-radius: 10px; background: #fff; }
.picker h3 { position: sticky; top: 0; z-index: 1; margin: 0; padding: 9px 14px; background: var(--ink); color: #fff; font: 800 13px/1.2 Arial, sans-serif; letter-spacing: .06em; text-transform: uppercase; }
.picker .empty { padding: 18px 14px; }
.pick { position: relative; display: flex; align-items: flex-start; gap: 12px; min-height: 48px; padding: 11px 14px; border-bottom: 1px solid var(--line); cursor: pointer; font-size: 16px; line-height: 1.35; }
.pick:hover { background: #eef7f5; }
.pick input { flex: none; width: 24px; height: 24px; margin: 0; accent-color: var(--ink); cursor: pointer; }
.pick.checked { background: var(--answer); font-weight: 700; }
.pick-text { flex: 1; }
.pick-order { flex: none; display: grid; place-items: center; min-width: 26px; height: 26px; padding: 0 6px; border: 2px solid var(--ink); border-radius: 999px; background: var(--hi); font: 900 13px/1 Arial, sans-serif; }
.pick-tag { flex: none; padding: 2px 8px; border: 1.5px solid var(--line); border-radius: 999px; font-size: 11px; font-weight: 800; color: var(--muted); white-space: nowrap; }
/* The ticked questions in board order, to review, reorder or remove. */
.picked { margin: 0 0 14px; padding: 10px 12px; border: 2px solid var(--ink); border-radius: 10px; background: #fff6de; }
.picked ol { list-style: none; margin: 8px 0 0; padding: 0; }
.picked li { display: flex; align-items: center; gap: 10px; padding: 5px 0; border-top: 1px solid var(--line); font-size: 15px; font-weight: 700; line-height: 1.3; }
.picked button { flex: none; display: grid; place-items: center; width: 48px; height: 48px; padding: 0; border: 2px solid var(--ink); border-radius: 50%; background: #fff; }
.picked button:hover:not(:disabled) { background: var(--ink); color: #fff; }
.picked button:disabled { opacity: .3; cursor: default; }
.picked button svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 3; stroke-linecap: round; stroke-linejoin: round; }
#board.manual #reshuffle, #board.manual .swap-btn { display: none; }
.count-row { display: flex; align-items: center; gap: 18px; flex-wrap: wrap; }
.stepper { display: inline-flex; align-items: stretch; border: 2px solid var(--ink); border-radius: 12px; overflow: hidden; background: #fff; }
.stepper button { width: 56px; min-height: 60px; border: 0; background: var(--hi); font: 900 28px/1 Arial, sans-serif; }
.stepper button:hover { background: var(--ink); color: var(--hi); }
.stepper input { width: 88px; border: 0; border-left: 2px solid var(--ink); border-right: 2px solid var(--ink); text-align: center; font: 900 30px/1 var(--display); background: #fff; -moz-appearance: textfield; appearance: textfield; }
.stepper input::-webkit-outer-spin-button, .stepper input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.presets { display: flex; gap: 8px; flex-wrap: wrap; }
.presets button { width: 52px; height: 52px; border: 2px solid var(--ink); border-radius: 50%; background: #fff; font-weight: 900; font-size: 17px; }
.presets button[aria-pressed="true"] { background: var(--ink); color: #fff; }
.check { display: inline-flex; align-items: center; gap: 12px; min-height: 48px; margin-top: 14px; font-weight: 700; cursor: pointer; }
.check input { width: 24px; height: 24px; accent-color: var(--ink); }

.launch {
  position: sticky; bottom: 0; z-index: 5; display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
  margin-top: 20px; padding: 12px clamp(16px, 5vw, 64px) max(12px, env(safe-area-inset-bottom)); background: var(--board-deep); color: #fff;
  border-top: 1px solid rgba(255, 255, 255, .15);
}
.summary { margin: 0; font-weight: 700; color: #dcebe9; }
.summary b { color: var(--hi); }
.primary { min-height: 56px; padding: 0 34px; border: 2px solid var(--ink); border-radius: 6px; background: var(--hi); color: var(--ink); box-shadow: 5px 5px 0 var(--pop); font: 900 20px/1 var(--display); letter-spacing: -.02em; text-transform: uppercase; }
.primary:hover:not(:disabled) { transform: translate(-2px, -2px); box-shadow: 7px 7px 0 var(--pop); }
.primary:disabled, .secondary:disabled { opacity: .4; cursor: not-allowed; }
.launch-actions { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.secondary { min-height: 56px; padding: 0 22px; border: 2px solid #fff; border-radius: 6px; background: none; color: #fff; font-weight: 800; font-size: 16px; }
.secondary:hover:not(:disabled) { background: #fff; color: var(--board); }

/* ---------- Board ---------- */
#board { position: fixed; inset: var(--standalone-top) 0 0 0; z-index: 10; display: flex; flex-direction: column; background-color: var(--board); background-image: var(--grid); background-size: 58px 58px; }
.board-bar { flex: none; display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; padding: 8px max(16px, env(safe-area-inset-right)) 8px max(16px, env(safe-area-inset-left)); background: var(--board-deep); color: #fff; border-bottom: 1px solid rgba(255, 255, 255, .15); }
.board-title { display: flex; align-items: baseline; gap: 16px; min-width: 0; }
.home-link { padding: 0; border: 0; background: none; cursor: pointer; }
.home-link:hover { color: #fff; }
.home-link { font: 900 clamp(26px, 4.4vh, 46px)/1 var(--display); letter-spacing: -.06em; text-transform: uppercase; color: var(--hi); white-space: nowrap; }
.board-title span { font-size: clamp(14px, 2.2vh, 22px); font-weight: 700; color: var(--soft); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.board-actions { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.pill { min-height: 48px; padding: 0 16px; border: 1px solid rgba(255, 255, 255, .4); border-radius: 999px; background: none; color: #fff; font-size: 14px; font-weight: 800; white-space: nowrap; }
.pill:hover { background: #fff; color: var(--board); }
.pill.icon { width: 48px; padding: 0; }
.pill svg { display: block; width: 20px; height: 20px; margin: 0 auto; fill: none; stroke: currentColor; stroke-width: 2.4; stroke-linecap: round; stroke-linejoin: round; }
#fullscreen .exit, #fullscreen[aria-pressed="true"] .enter { display: none; }
#fullscreen[aria-pressed="true"] .exit { display: inline; }
.pill.solid { border: 2px solid var(--ink); background: var(--hi); color: var(--ink); }
.pill.solid:hover { background: #fff; }
.pill:disabled { opacity: .4; cursor: not-allowed; }
.pill:disabled:hover { background: none; color: #fff; }
.more-toggle { display: none; }
/* On one line the date gives way first, so the buttons never wrap under the title. */
@media (min-width: 1000px) {
  .board-bar, .board-actions { flex-wrap: nowrap; }
  .board-title { flex: 1 1 0; }
  .home-link, .board-actions { flex: none; }
}
@media (min-width: 1000px) and (max-width: 1199px) {
  .board-actions { gap: 6px; }
  .board-actions .pill:not(.icon) { padding: 0 12px; font-size: 13px; }
}
/* A strip under the board while part of it is below the bottom edge. */
.more-below { flex: none; display: flex; align-items: center; justify-content: center; gap: 6px; width: 100%; min-height: 48px; padding: 0 16px env(safe-area-inset-bottom); border: 0; border-top: 1px solid rgba(255, 255, 255, .15); background: var(--board-deep); color: var(--hi); font-size: 15px; font-weight: 900; }
.more-below:hover { color: #fff; }
.more-below svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 3; stroke-linecap: round; stroke-linejoin: round; }

.board-area { flex: 1; min-height: 0; overflow: auto; padding: 2vh max(2vw, env(safe-area-inset-right)) 2vh max(2vw, env(safe-area-inset-left)); }
.questions { --q: 40px; list-style: none; margin: 0; padding: 0; column-gap: 1.6vw; font-size: var(--q); line-height: 1.22; }
.q { break-inside: avoid; display: grid; grid-template-columns: auto 1fr auto; gap: .5em; align-items: start; margin: 0 0 .36em; padding: .3em .4em .3em .34em; border: 2px solid var(--ink); border-radius: .22em; background: var(--card); color: var(--ink); }
.q-num { display: grid; place-items: center; width: 1.5em; height: 1.5em; border: 2px solid var(--ink); border-radius: 50%; background: var(--hi); font: 900 .78em/1 var(--display); margin-top: .03em; }
.neg { color: #d0182b; font-weight: 900; }
/* Mass number over atomic number, right-aligned against the symbol. The stack has no height of its own, so the line keeps its spacing. */
sub, sup { font-size: .68em; line-height: 0; }
.nuclide { white-space: nowrap; }
.nuclide-numbers { display: inline-flex; flex-direction: column; align-items: flex-end; height: 0; margin-right: .04em; font-size: .6em; line-height: 1; vertical-align: .5em; }
.q-text { margin: 0; padding-top: .04em; font-weight: 700; text-wrap: pretty; }
.q-figure { margin: .3em 0 .1em; }
.q-figure button { display: block; width: 100%; padding: 0; border: 0; background: none; cursor: zoom-in; }
/* --ratio (width / height) is set once the image has loaded. */
.q-figure img { display: block; width: min(100%, calc(5.8em * var(--ratio, 1.5))); height: auto; aspect-ratio: var(--ratio, 1.5); border: 2px solid var(--line); border-radius: .16em; background: #fff; }
.q-steps { list-style: none; margin: .3em 0 .1em; padding: 0; font-size: .74em; line-height: 1.25; }
.q-steps li { display: grid; grid-template-columns: 1.5em 1fr; gap: .4em; align-items: start; padding: .16em 0; border-top: 1px solid var(--line); }
.q-steps b { display: grid; place-items: center; width: 1.45em; height: 1.45em; border: 2px solid var(--ink); border-radius: .25em; background: var(--pop); font-weight: 900; }
.q.method .swap-btn { display: none; }
.q-answer { margin: .3em 0 .06em; padding: .22em .4em; border-left: .18em solid var(--answer-edge); border-radius: .1em; background: var(--answer); font-weight: 700; white-space: pre-line; text-wrap: pretty; }
.questions.measuring .q-answer { display: none; }
.q-actions { display: flex; gap: .2em; align-items: center; }
.q-actions button { min-height: 48px; min-width: 48px; height: 1.5em; padding: 0 .7em; border: 2px solid var(--ink); border-radius: 999px; background: #fff; font-size: max(15px, .42em); font-weight: 800; white-space: nowrap; }
.q-actions .ans-btn { background: var(--pop); }
.q-actions .ans-btn[aria-pressed="true"] { background: var(--ink); color: #fff; }
.q-actions button:hover { transform: translate(-1px, -1px); }
.q-actions .swap-btn { display: grid; place-items: center; padding: 0; }
.q-actions .swap-btn svg { width: 1.3em; height: 1.3em; fill: none; stroke: currentColor; stroke-width: 2.4; stroke-linecap: round; stroke-linejoin: round; }

.keys { position: fixed; inset: 0; z-index: 30; display: grid; place-items: center; padding: 16px; overflow: auto; background: rgba(3, 12, 30, .8); }
.keys-card { width: min(100%, 460px); padding: 20px 22px; border: 2px solid var(--ink); border-radius: 12px; background: var(--card); color: var(--ink); box-shadow: 6px 6px 0 var(--hi); }
.keys-card h2 { margin: 0; font: 900 24px/1 var(--display); letter-spacing: -.04em; text-transform: uppercase; }
.keys-card h3 { margin: 16px 0 4px; font-size: 12px; font-weight: 900; letter-spacing: .12em; text-transform: uppercase; color: var(--muted); }
.keys-card dl { margin: 0; }
.keys-card dl div { display: grid; grid-template-columns: 112px 1fr; align-items: center; gap: 10px; padding: 5px 0; border-top: 1px solid var(--line); }
.keys-card dd { margin: 0; font-weight: 700; }
.keys-card kbd { display: inline-block; min-width: 28px; padding: 3px 7px; border: 2px solid var(--ink); border-radius: 6px; background: #fff; font: 700 13px/1.2 ui-monospace, Menlo, Consolas, monospace; text-align: center; }
.keys-card .pill { margin-top: 16px; }

.lightbox { position: fixed; inset: 0; z-index: 30; display: grid; grid-template-rows: 1fr auto; justify-items: center; align-items: center; gap: 2vh; padding: 3vh 3vw; background: rgba(3, 12, 30, .92); }
.lightbox img { max-width: 94vw; max-height: 82vh; width: auto; height: 100%; min-height: 0; object-fit: contain; border: 2px solid var(--ink); border-radius: 12px; background: #fff; }

/* Buttons under the text: on a phone, and in two columns on a narrow board. */
.questions.stacked .q { grid-template-columns: auto 1fr; }
.questions.stacked .q-actions { grid-column: 1 / -1; justify-content: flex-end; }
@media (max-width: 700px) {
  .hero { padding-top: 18px; padding-bottom: 42px; }
  .lead { margin-top: 14px; }
  .launch { display: grid; grid-template-columns: 1fr; gap: 8px; margin-top: 16px; padding-top: 8px; }
  .summary { font-size: 14px; }
  .launch-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 10px; }
  .launch .secondary, .launch .primary { min-height: 48px; padding: 0 10px; }
  .launch .secondary { font-size: 15px; }
  .launch .primary { grid-column: 1 / -1; font-size: 18px; }
  .picked li { flex-wrap: wrap; }
  .picked .pick-text { flex: 1 1 calc(100% - 46px); }
  .picked li button:first-of-type { margin-left: auto; }
  .board-title span { display: none; }
  #cards .board-title { flex-wrap: wrap; gap: 4px 12px; }
  #cards .board-title span { display: inline; font-size: 14px; }
  /* The less-used board buttons fold into the "More options" button. */
  .more-toggle { display: block; }
  #board .board-actions:not(.open) .extra { display: none; }
  .board-actions .pill:not(.icon) { padding: 0 11px; font-size: 13px; }
  #cards [data-keys] { display: none; } /* no keyboard on a phone */
  #sheet-view .sheet-bar { gap: 8px 10px; }
  #sheet-view .sheet-bar strong { font-size: 16px; }
  #sheet-view .segmented button { padding: 0 10px; font-size: 13px; }
  #sheet-view .sheet-note { order: 3; flex-basis: 100%; font-size: 12px; }
  .q { grid-template-columns: auto 1fr; }
  .q-actions { grid-column: 1 / -1; justify-content: flex-end; }
}
/* ---------- Flashcards ---------- */
#cards { position: fixed; inset: var(--standalone-top) 0 0 0; z-index: 10; display: flex; flex-direction: column; background-color: var(--board); background-image: var(--grid); background-size: 58px 58px; }
.cards-area { flex: 1; min-height: 0; overflow: auto; display: grid; place-items: center; padding: 3vh max(16px, 3vw); }
.flashcard { width: min(100%, 900px); padding: clamp(18px, 3.5vmin, 40px); border: 2px solid var(--ink); border-radius: 14px; background: var(--card); color: var(--ink); box-shadow: 8px 8px 0 var(--hi); font-size: clamp(21px, 4.2vmin, 40px); line-height: 1.25; }
/* The card turns over to show its answer: both faces share one grid cell, so
   the card is as tall as the taller face. */
.flip { width: min(100%, 900px); perspective: 1800px; }
.flip-inner { display: grid; transform-style: preserve-3d; transition: transform .6s cubic-bezier(.3, .7, .2, 1); }
.flip.flipped .flip-inner { transform: rotateY(180deg); }
.flip.no-anim .flip-inner { transition: none; }
.face { grid-area: 1 / 1; width: auto; display: flex; flex-direction: column; -webkit-backface-visibility: hidden; backface-visibility: hidden; }
.face.back { transform: rotateY(180deg); box-shadow: 8px 8px 0 var(--pop); }
.face .card-actions { margin-top: auto; padding-top: 1em; }
.card-recap { margin: 0; font-size: .62em; font-weight: 700; color: var(--muted); }
.card-unflip { align-self: center; min-height: 48px; margin-top: 10px; padding: 0 12px; border: 0; background: none; font-size: 15px; font-weight: 800; text-decoration: underline; color: var(--muted); }
.card-unflip:hover { color: var(--ink); }
@media (prefers-reduced-motion: reduce) { .flip-inner { transition: none; } }
.card-topic { margin: 0 0 .9em; font-size: max(12px, .38em); font-weight: 900; letter-spacing: .12em; text-transform: uppercase; color: var(--muted); }
.card-question { margin: 0; font-weight: 700; text-wrap: pretty; }
.flashcard .q-answer { margin-top: .7em; }
.card-actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 1em; }
.flashcard.done .card-actions { margin-top: 1em; }
.card-actions button { flex: 1 1 180px; min-height: 60px; font-size: 18px; }
.card-actions .ghost { font-size: 17px; }
.flashcard.done .card-topic { margin: .6em 0 0; }

/* ---------- Worksheet ---------- */
#sheet-view { position: fixed; inset: var(--standalone-top) 0 0 0; z-index: 20; display: flex; flex-direction: column; background: #47595b; }
.sheet-bar { flex: none; display: flex; align-items: center; justify-content: space-between; gap: 12px 20px; flex-wrap: wrap; padding: 8px 16px; background: var(--board-deep); color: #fff; }
.sheet-bar strong { font: 900 22px/1 var(--display); letter-spacing: -.04em; text-transform: uppercase; color: var(--hi); }
/* On the dark bar the chosen page is the bright one. */
.sheet-bar .segmented { border-color: rgba(255, 255, 255, .6); background: none; }
.sheet-bar .segmented button[aria-pressed="true"] { background: var(--hi); color: var(--ink); }
.sheet-note { flex: 1 1 260px; margin: 0; font-size: 13px; color: var(--soft); }
.sheet.key .sheet-table td { height: auto; }
.sheet.key .sheet-q img { max-height: 30mm; }
.sheet-scroll { flex: 1; min-height: 0; overflow: auto; padding: 20px 12px 40px; }
.sheet { width: 210mm; max-width: 100%; min-height: 297mm; margin: 0 auto; padding: 14mm; background: #fff; color: #000; font: 11.5pt/1.35 Arial, Helvetica, sans-serif; box-shadow: 0 8px 30px rgba(0, 0, 0, .35); }
.sheet-head { display: flex; flex-wrap: wrap; align-items: baseline; justify-content: space-between; gap: 2mm 6mm; border-bottom: 2pt solid #000; padding-bottom: 2mm; }
.sheet-head h1 { margin: 0; white-space: nowrap; font: 900 22pt/1 var(--display); letter-spacing: -.04em; text-transform: uppercase; }
.sheet-head p { flex: 1 1 50mm; margin: 0; font-size: 9.5pt; text-align: right; color: #333; }
.sheet-info { display: grid; grid-template-columns: auto 2.2fr auto 1fr auto 1.2fr; align-items: end; gap: 0 3mm; margin: 6mm 0 5mm; font-weight: 700; }
.sheet-info i { border-bottom: 1pt solid #000; height: 7mm; }
.sheet-table { width: 100%; border-collapse: collapse; table-layout: fixed; }
.sheet-table th { padding: 2mm 3mm; border: 1pt solid #000; background: #e9e9e9; text-align: left; font-size: 10pt; letter-spacing: .06em; text-transform: uppercase; -webkit-print-color-adjust: exact; print-color-adjust: exact; }
.sheet-table td { padding: 3mm; border: 1pt solid #000; vertical-align: top; height: 24mm; }
.sheet-table tr { break-inside: avoid; }
.sheet-q { display: grid; grid-template-columns: 7mm 1fr; }
.sheet-q b { font-weight: 900; }
.sheet-q img { display: block; margin-top: 2mm; max-width: 100%; max-height: 42mm; }
.sheet-steps { list-style: none; margin: 2mm 0 0; padding: 0; }
.sheet-steps li { display: grid; grid-template-columns: 6mm 1fr; padding: 1mm 0; }
.sheet-a { white-space: pre-line; color: #14406b; }

@media print {
  @page { size: A4; margin: 13mm; }
  html, body { background: #fff; }
  #setup, #board, #cards, #lightbox, #keys, .sheet-bar { display: none !important; }
  #sheet-view { position: static; display: block; background: none; }
  .sheet-scroll { overflow: visible; padding: 0; }
  .sheet { width: auto; min-height: 0; padding: 0; box-shadow: none; }
  .sheet-table thead { display: table-header-group; }
  .sheet-a { color: #000; }
}
.copyright { margin: 24px 0 0; font-size: 13px; color: var(--muted); }