:root {
  --bg: #eef3f2; --card: #ffffff; --ink: #142624; --muted: #5f716f; --line: #dde6e4;
  --accent: #0f7c8c; --accent-ink: #ffffff; --accent-soft: #e2f2f3; --err: #b23b3b; --ok: #2fa36b;
  --radius: 18px; --shadow: 0 1px 2px rgba(16,40,38,.06), 0 8px 24px rgba(16,40,38,.08);
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; color: var(--ink); background: var(--bg);
  background-image: radial-gradient(1200px 400px at 50% -120px, #d4ebe9 0%, rgba(212,235,233,0) 70%);
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.45;
}
.wrap { max-width: 860px; margin: 0 auto; padding: 28px 18px 32px; }

/* header */
.top h1 { margin: 4px 0 2px; font-size: clamp(1.5rem, 6vw, 2.4rem); letter-spacing: -.02em; overflow-wrap: anywhere; }
.top h1 .slash { color: var(--accent); }
.pick-note { margin: 4px 0 10px; font-size: .82rem; color: var(--muted); font-style: italic; }
.eyebrow { margin: 0; font-size: .75rem; letter-spacing: .14em; text-transform: uppercase; color: var(--accent); font-weight: 700; }
.sub { margin: 0; color: var(--muted); }

/* selector */
.picker {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 6px;
  background: var(--card); padding: 6px; border-radius: 16px; box-shadow: var(--shadow); margin-bottom: 18px;
}
.pill {
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 1px;
  padding: 10px 8px; border-radius: 12px; text-decoration: none; color: var(--ink);
  transition: background .15s, color .15s; text-align: center; min-height: 56px;
}
.pill:hover { background: var(--accent-soft); }
.pill:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }
.pill-name { font-weight: 650; font-size: .95rem; }
.pill-cfs { font-size: .78rem; color: var(--muted); font-variant-numeric: tabular-nums; }
.pill.active { background: var(--accent); color: var(--accent-ink); box-shadow: 0 4px 12px rgba(15,124,140,.35); }
.pill.active .pill-cfs { color: rgba(255,255,255,.85); }

/* detail panel */
.panel { background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow); padding: 24px 26px 22px; animation: fade .2s ease; }
.panel[hidden] { display: none; }
@keyframes fade { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }
.panel-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; }
.water { margin: 0; color: var(--muted); font-size: .85rem; font-weight: 600; text-transform: uppercase; letter-spacing: .08em; }
.panel h2 { margin: 2px 0 0; font-size: 1.6rem; letter-spacing: -.01em; }
.badge { font-size: .7rem; font-weight: 700; letter-spacing: .08em; color: var(--accent); background: var(--accent-soft); padding: 5px 9px; border-radius: 999px; }

.reading { margin: 18px 0 8px; }
.cfs { margin: 0; font-size: clamp(3.6rem, 12vw, 5.5rem); font-weight: 800; line-height: 1; letter-spacing: -.03em; color: var(--accent); font-variant-numeric: tabular-nums; }
.cfs .unit { font-size: 1.1rem; font-weight: 700; letter-spacing: .06em; color: var(--muted); margin-left: 10px; }
.cfs.na { color: #b7c3c1; }
.time { margin: 10px 0 0; color: var(--muted); font-size: .95rem; display: flex; align-items: center; gap: 8px; }
.dot { width: 8px; height: 8px; border-radius: 50%; background: var(--ok); box-shadow: 0 0 0 4px rgba(47,163,107,.15); }
.err { color: var(--err); margin: 8px 0 0; }

/* chart */
.chart-card { margin-top: 20px; border: 1px solid var(--line); border-radius: 14px; padding: 14px 16px 10px; }
.chart-head { display: flex; justify-content: space-between; align-items: baseline; gap: 10px; flex-wrap: wrap; margin-bottom: 8px; }
.chart-head h3 { margin: 0; font-size: .95rem; }
.stats { display: flex; gap: 16px; font-size: .9rem; font-variant-numeric: tabular-nums; }
.stats em { font-style: normal; color: var(--muted); font-size: .75rem; text-transform: uppercase; letter-spacing: .06em; margin-right: 4px; }
.stats small { color: var(--muted); margin-left: 3px; }
.chart { position: relative; color: var(--accent); padding: 0 0 22px 0; }
.chart svg { display: block; width: 100%; height: 200px; overflow: visible; cursor: crosshair; }
.chart .line { fill: none; stroke: currentColor; stroke-width: 2.2; vector-effect: non-scaling-stroke; stroke-linejoin: round; }
.chart .grid { stroke: var(--line); stroke-width: 1; vector-effect: non-scaling-stroke; }
.chart .hover-line { stroke: var(--muted); stroke-width: 1; stroke-dasharray: 3 3; vector-effect: non-scaling-stroke; }
.ylab { position: absolute; left: 4px; font-size: .7rem; color: var(--muted); background: rgba(255,255,255,.8); padding: 0 3px; border-radius: 4px; pointer-events: none; }
.ytop { top: 2px; } .ybot { bottom: 26px; }
.xlabels { position: absolute; left: 0; right: 0; bottom: 0; height: 18px; }
.xlabels span { position: absolute; transform: translateX(-50%); font-size: .72rem; color: var(--muted); white-space: nowrap; }
.hover-dot { position: absolute; width: 10px; height: 10px; margin: -5px 0 0 -5px; border-radius: 50%; background: var(--accent); border: 2px solid #fff; box-shadow: 0 0 0 1px var(--accent); pointer-events: none; }
.tip { position: absolute; top: -8px; transform: translate(-50%, -100%); background: var(--ink); color: #fff; font-size: .75rem; padding: 4px 8px; border-radius: 6px; white-space: nowrap; pointer-events: none; }

.meta { margin-top: 18px; display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap; }
.gauge { margin: 0; color: var(--muted); font-size: .85rem; flex: 1 1 320px; }
.src { color: var(--accent); font-weight: 650; text-decoration: none; font-size: .9rem; white-space: nowrap; }
.src:hover { text-decoration: underline; }

footer { text-align: center; color: var(--muted); font-size: .78rem; margin-top: 22px; }
footer a { color: var(--accent); }

/* mobile: selector becomes a 2x2 grid, tighter panel */
@media (max-width: 620px) {
  .wrap { padding: 20px 12px 28px; }
  .picker { grid-template-columns: repeat(2, 1fr); }
  .panel { padding: 20px 18px 18px; }
  .panel h2 { font-size: 1.35rem; }
  .chart svg { height: 160px; }
  .stats { gap: 12px; font-size: .85rem; }
  .stats small { display: none; }
}
@media (prefers-reduced-motion: reduce) { .panel { animation: none; } }