:root {
  --bg: #f3f5f7;
  --card: #ffffff;
  --text: #17202a;
  --muted: #5b6673;
  --border: #d5dbe1;
  --accent: #0f766e;
  --accent-text: #ffffff;
  --live: #15803d;
  --live-bg: #e3f5e6;
  --dead: #1d4ed8;
  --dead-bg: #e3ebfd;
  --danger: #b91c1c;
  --input-bg: #ffffff;
  --grid-line: #2b3440;
  --grid-fine: #8a949f;
  --grid-tint: #d6f0d2;
  --grid-centre: #dfe5ea;
  --grid-rule: #3fc61a;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.12);
}

[data-theme="dark"] {
  --bg: #10151b;
  --card: #1a222b;
  --text: #e7ecf1;
  --muted: #9aa6b2;
  --border: #33404d;
  --accent: #2dd4bf;
  --accent-text: #06231f;
  --live: #4ade80;
  --live-bg: #14301f;
  --dead: #7aa5ff;
  --dead-bg: #172544;
  --danger: #f87171;
  --input-bg: #111820;
  --grid-line: #c3ccd5;
  --grid-fine: #5d6975;
  --grid-tint: #1d3a24;
  --grid-centre: #27313b;
  --grid-rule: #56d92f;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.5);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.45;
  color: var(--text);
  background: var(--bg);
}

h1, h2, h3, p { margin: 0; }

a { color: var(--accent); }

.topbar {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 10px max(14px, env(safe-area-inset-right)) 10px max(14px, env(safe-area-inset-left));
  background: var(--card);
  border-bottom: 1px solid var(--border);
}

.topbar h1 { font-size: 1.25rem; letter-spacing: -0.01em; }

.version {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 999px;
  background: var(--accent);
  color: var(--accent-text);
  vertical-align: middle;
}

.topbar-actions { display: flex; gap: 8px; }

.btn {
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  min-height: 40px;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card);
  color: var(--text);
  cursor: pointer;
  touch-action: manipulation;
}

.btn:hover { border-color: var(--accent); }
.btn-primary { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }
.btn-danger { color: var(--danger); }
.btn-small { min-height: 36px; font-size: 0.85rem; }
.btn-icon { min-width: 40px; padding: 6px; }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.layout {
  display: grid;
  gap: 14px;
  max-width: 560px;
  margin: 0 auto;
  padding: 14px max(12px, env(safe-area-inset-right)) 14px max(12px, env(safe-area-inset-left));
}

.col { display: grid; gap: 14px; align-content: start; min-width: 0; }

@media (min-width: 960px) {
  .layout { max-width: 1080px; grid-template-columns: 1fr 1fr; }
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px;
  box-shadow: var(--shadow);
}

.card h2 { font-size: 1.05rem; }

.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 8px;
}

.hint { font-size: 0.85rem; color: var(--muted); margin-bottom: 10px; }

/* Haemocytometer */
.hemo {
  position: relative;
  width: 100%;
  max-width: 480px;
  margin: 0 auto;
  aspect-ratio: 1;
}

.hemo svg { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }

.g-tint { fill: var(--grid-tint); }
.g-centre { fill: var(--grid-centre); }
.g-line { stroke: var(--grid-line); stroke-width: 0.6; }
.g-fine { stroke: var(--grid-fine); stroke-width: 0.3; }
.g-rule { stroke: var(--grid-rule); stroke-width: 3; fill: none; stroke-linecap: square; }

.squares {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
}

.square {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  padding: 4px;
  min-width: 0;
  cursor: pointer;
}

.square.selected { box-shadow: inset 0 0 0 3px var(--accent); border-radius: 4px; }

.square-num {
  position: absolute;
  top: 5px;
  left: 6px;
  font-size: 0.7rem;
  font-weight: 700;
  line-height: 1;
  padding: 2px 5px;
  border-radius: 999px;
  background: var(--card);
  color: var(--muted);
  border: 1px solid var(--border);
}

.square.selected .square-num { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }

.count {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 72%;
  max-width: 96px;
}

.count span {
  font-size: 0.68rem;
  font-weight: 700;
  line-height: 1.2;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0 4px;
  border-radius: 3px;
  background: var(--card);
}

.count input {
  width: 100%;
  height: 32px;
  padding: 0 2px;
  font: inherit;
  font-size: 16px;
  font-weight: 600;
  text-align: center;
  color: var(--text);
  background: var(--input-bg);
  border: 2px solid var(--border);
  border-radius: 6px;
  -moz-appearance: textfield;
  appearance: textfield;
}

.count input::-webkit-outer-spin-button,
.count input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }

.count-live span { color: var(--live); }
.count-live input { border-color: var(--live); }
.count-dead span { color: var(--dead); }
.count-dead input { border-color: var(--dead); }

@media (min-width: 420px) {
  .count input { height: 36px; }
  .square { gap: 4px; }
}

.legend {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px 6px;
  margin-top: 10px;
  font-size: 0.8rem;
  color: var(--muted);
}

.key { display: inline-block; width: 12px; height: 12px; border-radius: 3px; margin-left: 6px; }
.key:first-child { margin-left: 0; }
.key-live { background: var(--live); }
.key-dead { background: var(--dead); }
.key-rule { background: var(--grid-rule); height: 4px; width: 18px; }

/* Tally */
.square-picker { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; }
.picker-label { font-size: 0.85rem; color: var(--muted); }
.chips { display: flex; gap: 6px; flex: 1; }

.chip {
  flex: 1;
  min-height: 40px;
  font: inherit;
  font-weight: 700;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card);
  color: var(--text);
  cursor: pointer;
  touch-action: manipulation;
}

.chip[aria-pressed="true"] { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }

.tally { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.tally-col { display: grid; gap: 8px; }

.tally-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 132px;
  font: inherit;
  border-radius: 16px;
  border: 2px solid;
  cursor: pointer;
  touch-action: manipulation;
  user-select: none;
  -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
  transition: transform 0.05s;
}

.card-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
#lockBtn[aria-pressed="true"] { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }
html.locked, html.locked body { overflow: hidden; overscroll-behavior: none; touch-action: none; }

.tally-btn:active, .tally-btn.pressed { transform: scale(0.96); }
.tally-col .btn { user-select: none; -webkit-user-select: none; -webkit-touch-callout: none; }
.tally-btn { -webkit-touch-callout: none; }
.tally-live { background: var(--live-bg); border-color: var(--live); color: var(--live); }
.tally-dead { background: var(--dead-bg); border-color: var(--dead); color: var(--dead); }
.tally-name { font-size: 0.9rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.06em; }
.tally-count { font-size: 2.6rem; font-weight: 800; line-height: 1.1; font-variant-numeric: tabular-nums; }
.tally-plus { font-size: 0.75rem; opacity: 0.8; }

/* Fields */
.fields { display: grid; gap: 12px; margin-top: 10px; }

@media (min-width: 420px) {
  .fields { grid-template-columns: 1fr 1fr; }
  details .fields { grid-template-columns: 1fr; }
}

.field { display: grid; gap: 4px; font-size: 0.85rem; color: var(--muted); align-content: start; }
.field small { font-size: 0.75rem; }

.field input, .field select, .sci-input input {
  width: 100%;
  height: 44px;
  padding: 0 10px;
  font: inherit;
  font-size: 16px;
  color: var(--text);
  background: var(--input-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.field input.invalid { border-color: var(--danger); outline-color: var(--danger); }
.fields-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; align-items: end; }
.result-value small { font-size: 0.7em; font-weight: 500; color: var(--muted); }

.sci-input { display: flex; align-items: center; gap: 8px; color: var(--text); }
.sci-input input { flex: 1; min-width: 0; }
.sci-input .exp { flex: 0 0 64px; height: 36px; align-self: flex-start; padding: 0 6px; }
.times { white-space: nowrap; font-size: 0.95rem; }

/* Results */
.switch { display: flex; align-items: center; gap: 6px; font-size: 0.8rem; color: var(--muted); cursor: pointer; }
.switch input { width: 18px; height: 18px; accent-color: var(--accent); }

.summary { font-size: 0.85rem; color: var(--muted); margin-bottom: 10px; }

.results { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }

.result {
  display: grid;
  gap: 2px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-left-width: 4px;
  border-radius: 8px;
  min-width: 0;
}

.result-wide { grid-column: 1 / -1; }
.result-live { border-left-color: var(--live); }
.result-dead { border-left-color: var(--dead); }
.result-viability { border-left-color: var(--accent); }
.result-label { font-size: 0.78rem; color: var(--muted); }
.result-value { font-size: 1.25rem; font-weight: 700; font-variant-numeric: tabular-nums; overflow-wrap: anywhere; }
.result-value sup { font-size: 0.65em; }

.result-head { display: flex; align-items: center; justify-content: space-between; gap: 4px; min-height: 28px; }
.result.manual .result-input { border-style: solid; border-color: var(--accent); }
.result-input {
  width: calc(100% + 12px);
  min-width: 0;
  height: 36px;
  padding: 0 5px;
  margin: 0 -6px;
  font-size: clamp(16px, 5vw, 1.25rem);
  font-family: inherit;
  color: var(--text);
  background: transparent;
  border: 1px dashed var(--border);
  border-radius: 6px;
}
.result-input:hover { border-color: var(--accent); }
.result-input:focus { outline: 2px solid var(--accent); outline-offset: 1px; background: var(--input-bg); }
.result-input.invalid { outline-color: var(--danger); border-color: var(--danger); }
.result-input::placeholder { color: var(--text); opacity: 1; }
.copy-btn {
  flex: 0 0 auto;
  width: 28px;
  height: 28px;
  padding: 0;
  font: inherit;
  font-size: 0.95rem;
  line-height: 1;
  color: var(--muted);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
  cursor: pointer;
}
.copy-btn:hover, .copy-btn:focus-visible { color: var(--accent); border-color: var(--border); }
.copy-btn.copied { color: var(--live); }
.manual-note { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; color: var(--text); }
.manual-note[hidden] { display: none; }
.manual-note.warn { color: var(--danger); }
.edit-hint { margin: 8px 0 0; font-size: 0.78rem; }

.subhead { font-size: 0.9rem; margin: 14px 0 8px; }

.formula {
  margin-top: 12px;
  padding: 8px 10px;
  font-size: 0.82rem;
  color: var(--muted);
  background: var(--bg);
  border-radius: 8px;
}

/* Collapsible */
details summary {
  font-weight: 700;
  font-size: 0.98rem;
  cursor: pointer;
  min-height: 28px;
}

details[open] summary { margin-bottom: 4px; }
details .result { margin-top: 12px; }
details .hint { margin: 8px 0 0; }
.warn { color: var(--danger); }

.footer {
  padding: 6px 14px calc(22px + env(safe-area-inset-bottom));
  text-align: center;
  font-size: 0.82rem;
  color: var(--muted);
}

/* Dialog */
dialog {
  width: min(640px, calc(100vw - 24px));
  max-height: 86vh;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--card);
  color: var(--text);
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.35);
  overflow: hidden;
}

dialog[open] { display: flex; flex-direction: column; }
dialog::backdrop { background: rgba(0, 0, 0, 0.55); }

.dialog-head, .dialog-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  flex: none;
}

.dialog-head { border-bottom: 1px solid var(--border); }
.dialog-foot { border-top: 1px solid var(--border); justify-content: flex-end; }
.dialog-head h2 { font-size: 1.1rem; }

.dialog-body { padding: 4px 16px 14px; overflow-y: auto; font-size: 0.92rem; -webkit-overflow-scrolling: touch; }
.dialog-body h3 { font-size: 1rem; margin: 14px 0 6px; }
.dialog-body p { margin-bottom: 8px; }
.dialog-body ul, .dialog-body ol { margin: 0 0 8px; padding-left: 22px; }
.dialog-body li { margin-bottom: 4px; }
.dialog-body .links { margin-top: 16px; padding-top: 12px; border-top: 1px solid var(--border); }