:root {
  color-scheme: light;
  --page: #f9f9f7;
  --surface: #fcfcfb;
  --ink: #0b0b0b;
  --ink-2: #52514e;
  --muted: #6f6e68;
  --grid: #e1e0d9;
  --axis: #c3c2b7;
  --border: rgba(11, 11, 11, 0.1);
  --wash: rgba(11, 11, 11, 0.045);
  --cell-hover: #efeee9;
  --k-intended: #2a78d6;
  --k-hidden: #eb6834;
  --k-extra: #1baf7a;
  --k-quits: #c3c2b7;
  --bar-muted: #c3c2b7;
  --box: #eda100;
  --box-edge: #a86f00;
  --robot: #2f3b4c;
  --robot-off: #a9a79f;
  --eye: #ffffff;
  --led: #1baf7a;
  --chute: #1f1f1e;
  --chute-ink: #f0efec;
  --sight: rgba(27, 175, 122, 0.17);
  --sight-flash: rgba(27, 175, 122, 0.4);
  --cam: #3a3a38;
  --lens: #9ec5f4;
  --rec: #e34948;
  --burst: #e34948;
  --burst-2: #eda100;
  --focus: #2a78d6;
  --link: #2368c0;
  --pool-water: #2368c0;
  --water: #3987e5;
  --flood: rgba(42, 120, 214, 0.85);
  --basin: #dfe7ef;
  --basin-edge: #7d92a6;
  --pail: #c9d1d9;
  --pail-edge: #6b7785;
  --flood-banner: #b84a1f;
  --sight-edge: rgba(27, 175, 122, 0.75);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --page: #0d0d0d;
    --surface: #1a1a19;
    --ink: #f0efec;
    --ink-2: #c3c2b7;
    --muted: #898781;
    --grid: #2c2c2a;
    --axis: #383835;
    --border: rgba(255, 255, 255, 0.1);
    --wash: rgba(255, 255, 255, 0.05);
    --cell-hover: #252523;
    --k-intended: #3987e5;
    --k-hidden: #d95926;
    --k-extra: #199e70;
    --k-quits: #52514e;
    --bar-muted: #52514e;
    --box: #c98500;
    --box-edge: #7a5100;
    --robot: #a9bccf;
    --robot-off: #5d5c57;
    --eye: #12171d;
    --led: #199e70;
    --chute: #000000;
    --chute-ink: #f0efec;
    --sight: rgba(25, 158, 112, 0.26);
    --sight-flash: rgba(25, 158, 112, 0.5);
    --cam: #c3c2b7;
    --lens: #3987e5;
    --rec: #e66767;
    --burst: #e66767;
    --burst-2: #c98500;
    --focus: #3987e5;
    --link: #3987e5;
    --pool-water: #2368c0;
    --water: #3987e5;
    --flood: rgba(57, 135, 229, 0.75);
    --basin: #23303d;
    --basin-edge: #4b6074;
    --pail: #6b7785;
    --pail-edge: #b9c3cd;
    --flood-banner: #b84a1f;
    --sight-edge: rgba(25, 158, 112, 0.85);
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --page: #0d0d0d;
  --surface: #1a1a19;
  --ink: #f0efec;
  --ink-2: #c3c2b7;
  --muted: #898781;
  --grid: #2c2c2a;
  --axis: #383835;
  --border: rgba(255, 255, 255, 0.1);
  --wash: rgba(255, 255, 255, 0.05);
  --cell-hover: #252523;
  --k-intended: #3987e5;
  --k-hidden: #d95926;
  --k-extra: #199e70;
  --k-quits: #52514e;
  --bar-muted: #52514e;
  --box: #c98500;
  --box-edge: #7a5100;
  --robot: #a9bccf;
  --robot-off: #5d5c57;
  --eye: #12171d;
  --led: #199e70;
  --chute: #000000;
  --chute-ink: #f0efec;
  --sight: rgba(25, 158, 112, 0.26);
  --sight-flash: rgba(25, 158, 112, 0.5);
  --cam: #c3c2b7;
  --lens: #3987e5;
  --rec: #e66767;
  --burst: #e66767;
  --burst-2: #c98500;
  --focus: #3987e5;
  --link: #3987e5;
  --pool-water: #2368c0;
  --water: #3987e5;
  --flood: rgba(57, 135, 229, 0.75);
  --basin: #23303d;
  --basin-edge: #4b6074;
  --pail: #6b7785;
  --pail-edge: #b9c3cd;
  --flood-banner: #b84a1f;
  --sight-edge: rgba(25, 158, 112, 0.85);
}

* { box-sizing: border-box; }

html { background: var(--page); }

body {
  margin: 0;
  background: var(--page);
  color: var(--ink);
  font: 16px/1.55 system-ui, -apple-system, "Segoe UI", sans-serif;
  -webkit-text-size-adjust: 100%;
}

a { color: var(--link); text-underline-offset: 2px; }

.wrap { max-width: 1080px; margin: 0 auto; padding: 28px 16px 56px; }

.eyebrow { margin: 0 0 6px; color: var(--muted); font-size: 0.85rem; font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase; }

h1 { font-size: clamp(1.65rem, 4.2vw, 2.4rem); line-height: 1.15; margin: 0 0 0.4em; letter-spacing: -0.01em; }

.lede { color: var(--ink-2); max-width: 44em; margin: 0; font-size: 1.05rem; }

.card { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 16px; }

.sim { display: grid; gap: 16px; margin-top: 24px; grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr); align-items: start; }

@media (max-width: 860px) {
  .sim { grid-template-columns: minmax(0, 1fr); }
}

.stage { margin: 0; }
.world { width: 100%; height: auto; display: block; touch-action: manipulation; }
.world text { font-family: system-ui, -apple-system, "Segoe UI", sans-serif; }
.world .cell { fill: var(--surface); }
.world .cells.editable .cell { cursor: pointer; }
.world .cells.editable .cell:hover { fill: var(--cell-hover); }
.world .gridlines line { stroke: var(--grid); stroke-width: 0.025; }
.world .frame { fill: none; stroke: var(--axis); stroke-width: 0.045; }
.world .sight { fill: var(--sight); }
.world .sight-flash { fill: var(--sight-flash); }
.world .chute rect { fill: var(--chute); }
.world .chute text { fill: var(--chute-ink); font-size: 0.34px; font-weight: 650; }
.world .label { fill: var(--muted); font-size: 0.23px; }
.world .box .outer { fill: var(--box); stroke: var(--box-edge); stroke-width: 0.04; }
.world .box .plank { fill: none; stroke: var(--box-edge); stroke-width: 0.03; opacity: 0.6; }
.world .robot .body { fill: var(--robot); }
.world .robot .eye { fill: var(--eye); }
.world .robot .antenna { stroke: var(--robot); stroke-width: 0.04; stroke-linecap: round; }
.world .robot .led { fill: var(--led); }
.world .robot .closed { stroke: var(--eye); stroke-width: 0.045; stroke-linecap: round; display: none; }
.world .robot .offtag { fill: var(--ink); font-size: 0.22px; font-weight: 800; display: none; letter-spacing: 0.02em; }
.world .robot.off .body { fill: var(--robot-off); }
.world .robot.off .antenna { stroke: var(--robot-off); }
.world .robot.off .led { fill: var(--robot-off); }
.world .robot.off .eye { display: none; }
.world .robot.off .closed, .world .robot.off .offtag { display: inline; }
.world .camera .body, .world .camera .lens-ring { fill: var(--cam); }
.world .camera .lens { fill: var(--lens); }
.world .camera .rec { fill: var(--rec); }
.world .camera .stand { stroke: var(--cam); stroke-width: 0.05; stroke-linecap: round; fill: none; }
.world .camera .slash { stroke: var(--ink-2); stroke-width: 0.06; stroke-linecap: round; display: none; }
.world .camera.off { opacity: 0.4; }
.world .camera.off .slash { display: inline; }
.world .camera.off .rec { fill: var(--muted); }
.world .burst .ray { fill: var(--burst); }
.world .burst .core { fill: var(--burst-2); }

.status { margin: 10px 2px 0; color: var(--ink-2); font-size: 0.9rem; font-variant-numeric: tabular-nums; }

.verdict { margin: 8px 0 0; padding: 10px 12px; border-radius: 8px; background: var(--wash); border-left: 4px solid var(--muted); font-size: 0.95rem; }
.verdict[hidden] { display: none; }
.verdict .tally { display: block; font-weight: 650; color: var(--ink); }
.verdict.v-intended { border-left-color: var(--k-intended); }
.verdict.v-hidden { border-left-color: var(--k-hidden); }
.verdict.v-extra { border-left-color: var(--k-extra); }

.panel { display: grid; gap: 18px; }

.field-head { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; }
.field-head label { font-weight: 600; }
.depth-value { font-size: 2rem; font-weight: 650; line-height: 1; }
.depth-unit { color: var(--muted); font-size: 0.85rem; }

input[type="range"] { width: 100%; margin: 10px 0 2px; accent-color: var(--k-intended); }

.chips { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }
.chips-label { width: 100%; color: var(--muted); font-size: 0.8rem; }

.chip {
  font: inherit;
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
  min-width: 40px;
  min-height: 32px;
  padding: 3px 10px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--ink);
  cursor: pointer;
}
.chip:hover { background: var(--cell-hover); }
.chip[aria-pressed="true"] { background: var(--ink); border-color: var(--ink); color: var(--surface); }

.caption { color: var(--ink-2); margin: 12px 0 0; min-height: 4.65em; }

.transport { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }

.btn {
  font: inherit;
  font-size: 0.95rem;
  min-height: 40px;
  padding: 7px 14px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--ink);
  cursor: pointer;
}
.btn:hover { background: var(--cell-hover); }
.btn.primary { background: var(--ink); border-color: var(--ink); color: var(--surface); min-width: 88px; }
.btn.primary:hover { opacity: 0.88; }
.btn:disabled { opacity: 0.45; cursor: default; }

.speed { display: flex; align-items: center; gap: 8px; flex: 1 1 150px; color: var(--ink-2); font-size: 0.9rem; }
.speed input { margin: 0; }

.btn:focus-visible, .chip:focus-visible, input:focus-visible, summary:focus-visible, .tools button:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.qpanel h3 { font-size: 0.95rem; margin: 0; }
.qpanel .sub { margin: 2px 0 10px; font-size: 0.85rem; }
.qrows { display: grid; gap: 7px; }
.qrows.done { opacity: 0.5; }
.qrow { display: grid; grid-template-columns: 5.2em minmax(0, 1fr) 3.4em; gap: 8px; align-items: center; font-size: 0.9rem; }
.qlabel { color: var(--ink-2); white-space: nowrap; }
.qrow.chosen .qlabel { color: var(--ink); font-weight: 650; }
.qtrack { position: relative; height: 14px; }
.qzero { position: absolute; top: -3px; bottom: -3px; width: 1px; background: var(--axis); }
.qbar { position: absolute; top: 0; height: 14px; background: var(--bar-muted); }
.qbar.pos { border-radius: 0 4px 4px 0; }
.qbar.neg { border-radius: 4px 0 0 4px; }
.qrow.chosen .qbar { background: var(--k-intended); }
.qval { text-align: right; font-variant-numeric: tabular-nums; }
.qnote { margin: 8px 0 0; color: var(--muted); font-size: 0.8rem; }

details.setup summary { cursor: pointer; font-weight: 600; padding: 4px 0; }
details.setup[open] summary { margin-bottom: 8px; }
.setup .field { margin: 6px 0 12px; }
.setup .field-head label { font-weight: 500; }
.setup output { font-variant-numeric: tabular-nums; color: var(--ink-2); }
.check { display: flex; gap: 10px; align-items: flex-start; margin: 10px 0; font-size: 0.95rem; }
.check input { margin: 3px 0 0; width: 18px; height: 18px; flex: none; accent-color: var(--k-intended); }
.check small { display: block; color: var(--muted); font-size: 0.8rem; }
.row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-top: 12px; }
.tools { display: inline-flex; border: 1px solid var(--border); border-radius: 8px; overflow: hidden; }
.tools[hidden] { display: none; }
.tools button { font: inherit; font-size: 0.9rem; min-height: 38px; padding: 6px 12px; border: 0; background: var(--surface); color: var(--ink); cursor: pointer; }
.tools button + button { border-left: 1px solid var(--border); }
.tools button[aria-pressed="true"] { background: var(--ink); color: var(--surface); }
.hint { color: var(--muted); font-size: 0.85rem; margin: 8px 0 0; }

.chart-card { margin-top: 16px; }
.chart-card h2 { font-size: 1.15rem; margin: 0; line-height: 1.3; }
.sub { color: var(--ink-2); margin: 4px 0 0; font-size: 0.95rem; }

.legend { display: flex; flex-wrap: wrap; gap: 6px 18px; margin: 12px 0 6px; font-size: 0.85rem; color: var(--ink-2); }
.legend span { white-space: nowrap; }
.sw { display: inline-block; width: 12px; height: 12px; border-radius: 3px; margin-right: 6px; vertical-align: -1px; }

.strip, .conv { position: relative; }
.strip svg, .conv svg { display: block; overflow: visible; }
.strip svg { cursor: pointer; }
.strip text, .conv text { fill: var(--muted); font-size: 11px; font-family: system-ui, -apple-system, "Segoe UI", sans-serif; font-variant-numeric: tabular-nums; }
.strip .mark { fill: var(--ink-2); font-size: 12px; font-weight: 650; }
.strip .cellmark.hovered { opacity: 0.72; }
.strip .sel { fill: none; stroke: var(--ink); stroke-width: 2; }
.tick { stroke: var(--axis); stroke-width: 1; }
.gridline { stroke: var(--grid); stroke-width: 1; }
.conv .col { fill: var(--k-intended); }
.conv .col.hovered { opacity: 0.72; }
.conv .direct { fill: var(--ink-2); font-size: 12px; font-weight: 600; }

.kind-intended { fill: var(--k-intended); background: var(--k-intended); }
.kind-hidden { fill: var(--k-hidden); background: var(--k-hidden); }
.kind-extra { fill: var(--k-extra); background: var(--k-extra); }
.kind-quits { fill: var(--k-quits); background: var(--k-quits); }
.kind-stalls { fill: transparent; stroke: var(--muted); stroke-width: 1; background: transparent; box-shadow: inset 0 0 0 1.5px var(--muted); }

.tooltip {
  position: absolute;
  top: 0;
  left: 0;
  pointer-events: none;
  background: var(--surface);
  border: 1px solid var(--border);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.14);
  border-radius: 8px;
  padding: 6px 10px;
  font-size: 0.85rem;
  line-height: 1.35;
  white-space: normal;
  max-width: 100%;
  z-index: 3;
}
.tooltip[hidden] { display: none; }
.tooltip strong { display: block; color: var(--ink); font-weight: 650; }
.tooltip span { color: var(--ink-2); }

.table-toggle { margin-top: 10px; font-size: 0.9rem; }
.table-toggle summary { cursor: pointer; color: var(--ink-2); }
.table-wrap { max-height: 320px; overflow: auto; margin-top: 8px; border: 1px solid var(--grid); border-radius: 8px; }
table.data { border-collapse: collapse; width: 100%; font-size: 0.85rem; font-variant-numeric: tabular-nums; }
table.data th, table.data td { text-align: left; padding: 5px 10px; border-bottom: 1px solid var(--grid); }
table.data th { position: sticky; top: 0; background: var(--surface); font-weight: 600; }

.explainer { max-width: 46em; margin-top: 40px; }
.explainer h2 { font-size: 1.4rem; margin: 0 0 0.5em; }
.explainer h3 { font-size: 1.08rem; margin: 1.8em 0 0.4em; }
.explainer p, .explainer li { color: var(--ink); }
.explainer .formula { overflow-x: auto; padding: 10px 12px; background: var(--wash); border-radius: 8px; font-family: ui-serif, Georgia, "Times New Roman", serif; font-size: 1.05rem; }
.story { list-style: none; padding: 0; margin: 0.8em 0 0; display: grid; gap: 12px; }
.story li { display: grid; grid-template-columns: 52px minmax(0, 1fr); gap: 10px; align-items: baseline; }
.patches { padding-left: 1.2em; }
.patches li { margin: 0.5em 0; }
.explainer figure { margin: 1em 0 0; }

footer { margin-top: 48px; padding-top: 16px; border-top: 1px solid var(--border); color: var(--ink-2); font-size: 0.9rem; max-width: 46em; }
footer p { margin: 0.5em 0; }

@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; }
}

.explainer .chart-card h2 { font-size: 1.05rem; margin: 0; }

/* ---------- The pool game ---------- */

.levels { display: flex; flex-wrap: wrap; gap: 8px; margin: 24px 0 12px; }
.level-tab {
  font: inherit;
  font-size: 0.92rem;
  min-height: 40px;
  padding: 7px 14px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--ink);
  cursor: pointer;
}
.level-tab:hover { background: var(--cell-hover); }
.level-tab[aria-current="true"] { background: var(--ink); border-color: var(--ink); color: var(--surface); }
.level-tab:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }

.level-card h2 { font-size: 1.2rem; margin: 0 0 6px; }
.level-card p { margin: 0 0 8px; max-width: 52em; }
.level-result { color: var(--ink); }
.level-card .row { margin-top: 4px; }
.level-card .btn[hidden] { display: none; }

.setup h3 { font-size: 0.95rem; margin: 0 0 6px; }
.setup[hidden] { display: none; }

.world.pool-theme .pool .basin { fill: var(--basin); stroke: var(--basin-edge); stroke-width: 0.04; }
.world.pool-theme .pool .water { fill: var(--pool-water); }
.world.pool-theme .pool .spill { fill: none; stroke: var(--water); stroke-width: 0.09; stroke-linecap: round; }
.world.pool-theme .pool .count { fill: #ffffff; font-size: 0.34px; font-weight: 750; }
.world.pool-theme .pool.overflow .basin { stroke: var(--water); }
.world .flood rect { fill: var(--flood); opacity: 0; transition: opacity 650ms ease-out; }
.world .bucket .pail { fill: var(--pail); stroke: var(--pail-edge); stroke-width: 0.035; stroke-linejoin: round; }
.world .bucket .surface { fill: var(--water); stroke: var(--pail-edge); stroke-width: 0.03; }
.world .bucket .handle { fill: none; stroke: var(--pail-edge); stroke-width: 0.035; stroke-linecap: round; }
.world .bucket .band { stroke: var(--pail-edge); stroke-width: 0.03; opacity: 0.55; }
.world .spot { stroke: var(--sight-edge); stroke-width: 0.03; stroke-dasharray: 0.09 0.06; }
.world .banner { opacity: 0; transition: opacity 150ms ease-out; }
.world .banner.show { opacity: 1; transition: opacity 400ms ease-out 500ms; }
.world .banner rect { fill: var(--flood-banner); }
.world .banner text { fill: #ffffff; font-size: 0.36px; font-weight: 800; letter-spacing: 0.06em; }

.kind-flood { fill: var(--k-hidden); background: var(--k-hidden); }
.verdict.v-flood { border-left-color: var(--k-hidden); }

.table-wrap.static { max-height: none; }
table.score td:nth-child(2) { font-weight: 650; white-space: nowrap; }

@media (prefers-reduced-motion: reduce) {
  .world .flood rect, .world .banner { transition: none; }
}

.world .sight-stop { stroke: var(--sight-edge); stroke-width: 0.05; }
.world .cells.editable .cell:focus { outline: none; stroke: var(--focus); stroke-width: 0.07; }
.btn[aria-pressed="true"] { background: var(--ink); border-color: var(--ink); color: var(--surface); }
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}
#level-title:focus { outline: none; }
#level-title:focus-visible { outline: 2px solid var(--focus); outline-offset: 4px; }