:root {
  --color-bg:         #f5f7fa;
  --color-surface:    #ffffff;
  --color-border:     #dde1e7;
  --color-primary:    #005eb8;
  --color-primary-fg: #ffffff;
  --color-text:       #1a1a1a;
  --color-text-muted: #5a6375;
  --color-input-bg:   #f9fafc;
  --radius:           10px;
  --shadow:           0 1px 4px rgba(0,0,0,0.08);
  --font:             system-ui, -apple-system, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: var(--font);
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100dvh;
}

/* Centres content on wide screens; both header and main share it so they align */
.container {
  max-width: 880px;
  margin-inline: auto;
  padding-inline: 1.5rem;
}

/* ── Header ── */
header {
  background: var(--color-primary);
  color: var(--color-primary-fg);
  padding-block: 1rem 0;
}

header h1 {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 1rem;
}

/* ── Tab bar ── */
[role="tablist"] {
  display: flex;
  gap: 0.25rem;
  list-style: none;
}

[role="tab"] {
  padding: 0.6rem 1.1rem;
  border: none;
  background: transparent;
  color: rgba(255,255,255,0.85);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  border-radius: 6px 6px 0 0;
  transition: background 0.15s, color 0.15s;
}

[role="tab"]:hover {
  color: #fff;
  background: rgba(255,255,255,0.12);
}

[role="tab"][aria-selected="true"] {
  background: var(--color-surface);
  color: var(--color-primary);
}

/* ── Main content ── */
main {
  padding-block: 1.5rem;
}

[role="tabpanel"] { display: none; }
[role="tabpanel"].active { display: block; }

/* ── Tool headings ── */
.tool-header {
  margin-bottom: 1.5rem;
}

.tool-header h2 {
  font-size: 1.15rem;
  font-weight: 700;
}

.tool-header p {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-top: 0.3rem;
}

/* ── Converter layout ── */
.converter {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 1rem;
  align-items: center;
}

@media (max-width: 520px) {
  .converter {
    grid-template-columns: 1fr;
  }
  .converter-divider { justify-self: center; transform: rotate(90deg); }
}

.converter-panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.25rem;
}

.converter-panel h3 {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}

.converter-divider {
  font-size: 1.4rem;
  color: var(--color-text-muted);
  user-select: none;
  line-height: 1;
}

/* ── Input groups ── */
.input-row {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  margin-bottom: 0.9rem;
}

.input-row:last-child { margin-bottom: 0; }

.input-row label {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  white-space: nowrap;
  min-width: 3.5rem;
}

.input-row .field {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex: 1;
}

.input-row input[type="number"] {
  width: 100%;
  padding: 0.55rem 0.7rem;
  border: 1.5px solid var(--color-border);
  border-radius: 6px;
  background: var(--color-input-bg);
  font: inherit;
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--color-text);
  transition: border-color 0.15s;
  -moz-appearance: textfield;
}

.input-row input[type="number"]::-webkit-inner-spin-button,
.input-row input[type="number"]::-webkit-outer-spin-button {
  -webkit-appearance: none;
}

.input-row input[type="number"]:focus {
  outline: none;
  border-color: var(--color-primary);
}

.unit {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  white-space: nowrap;
}

/* ── Chart picker (sex toggle + measure pills) ── */
.chart-picker {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1rem;
  margin-bottom: 1rem;
}

.sex-toggle {
  display: inline-flex;
  gap: 3px;
  padding: 3px;
  background: var(--color-input-bg);
  border: 1.5px solid var(--color-border);
  border-radius: 8px;
}

.sex-btn {
  padding: 0.4rem 1.1rem;
  border: none;
  border-radius: 6px;
  background: transparent;
  color: var(--color-text-muted);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.sex-btn:hover { color: var(--color-text); }

.sex-btn[aria-pressed="true"] {
  background: var(--color-primary);
  color: var(--color-primary-fg);
  box-shadow: var(--shadow);
}

.measure-pills {
  display: flex;
  flex: 1 1 100%;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.pill {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.1rem;
  min-width: 5rem;
  padding: 0.4rem 0.85rem;
  border: 1.5px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-surface);
  color: var(--color-text);
  font: inherit;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}

.pill:hover { border-color: var(--color-primary); }

.pill .pill-measure { font-size: 0.9rem; font-weight: 600; line-height: 1.15; }
.pill .pill-range   { font-size: 0.72rem; color: var(--color-text-muted); line-height: 1; }

.pill.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-primary-fg);
  box-shadow: var(--shadow);
}
.pill.active .pill-range { color: rgba(255,255,255,0.85); }

/* ── Growth chart ── */
.chart-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 1rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.1rem 1.25rem;
  margin-bottom: 1rem;
}

.chart-controls .input-row {
  margin-bottom: 0;
  flex: 1 1 13rem;
}

.chart-controls select {
  padding: 0.55rem 0.5rem;
  border: 1.5px solid var(--color-border);
  border-radius: 6px;
  background: var(--color-input-bg);
  font: inherit;
  font-size: 0.95rem;
  color: var(--color-text);
  cursor: pointer;
}

.btn-clear {
  margin-left: auto;
  padding: 0.55rem 1.1rem;
  border: 1.5px solid var(--color-border);
  border-radius: 6px;
  background: var(--color-surface);
  color: var(--color-text-muted);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.btn-clear:hover { background: var(--color-bg); color: var(--color-text); }

.centile-readout {
  min-height: 1.4em;
  margin-bottom: 0.75rem;
  font-size: 0.95rem;
  font-weight: 600;
}

.centile-readout.normal { color: var(--color-primary); }
.centile-readout.edge   { color: #b8400f; }

.growth-chart {
  width: 100%;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 0.5rem;
}

.growth-chart .uplot { width: 100%; font-family: var(--font); }
.growth-chart .u-title { font-weight: 600; }

.chart-note {
  margin-top: 0.75rem;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  line-height: 1.45;
}

/* Value entry: kg field vs lb+oz fields vs cm field, toggled per measure */
.value-group {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex: 1;
  min-width: 0;
}
.value-group[hidden] { display: none; }
.value-group input[type="number"] { flex: 1 1 0; min-width: 0; }

.btn-add {
  margin-left: auto;
  padding: 0.55rem 1.2rem;
  border: 1.5px solid var(--color-primary);
  border-radius: 6px;
  background: var(--color-primary);
  color: var(--color-primary-fg);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}
.btn-add:hover { background: #004a92; }

/* ── Readings table ── */
.readings { margin-top: 1.25rem; }

.readings-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.5rem;
}

.readings-head h3 { font-size: 0.95rem; font-weight: 700; }

.readings-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 0.9rem;
}

.readings-table th,
.readings-table td {
  text-align: left;
  padding: 0.55rem 0.75rem;
  border-bottom: 1px solid var(--color-border);
}

.readings-table th {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-text-muted);
  background: var(--color-input-bg);
}

.readings-table tr:last-child td { border-bottom: none; }

.readings-table th:last-child,
.readings-table td:last-child {
  width: 1%;
  text-align: right;
  white-space: nowrap;
}

.btn-remove {
  width: 1.7rem;
  height: 1.7rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  background: var(--color-surface);
  color: var(--color-text-muted);
  font-size: 1.15rem;
  line-height: 1;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.btn-remove:hover { background: #fdecea; color: #d5281b; border-color: #f1b0a8; }