:root {
  --bg: #f3f6fb;
  --card: #fff;
  --ink: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
  --accent: #2563eb;
  --ok: #16a34a;
  --warn: #d97706;
  --bad: #dc2626;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --card: #131c2e;
    --ink: #e5eaf5;
    --muted: #94a3b8;
    --line: #243049;
    --accent: #60a5fa;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.5 system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
}

.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  max-width: 960px;
  margin: 0 auto;
  padding: 18px 16px 6px;
}

h1 {
  margin: 0;
  font-size: 26px;
  letter-spacing: -0.02em;
}

h2 {
  margin: 0 0 8px;
  font-size: 16px;
}

.sub {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.conn {
  padding: 4px 12px;
  border-radius: 999px;
  background: var(--card);
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
  white-space: nowrap;
}

.conn.on {
  color: var(--ok);
  border-color: var(--ok);
}

.conn.off {
  color: var(--bad);
  border-color: var(--bad);
}

main {
  display: grid;
  gap: 14px;
  max-width: 960px;
  margin: 0 auto;
  padding: 10px 16px 40px;
}

.card {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--card);
}

.status {
  text-align: center;
  border-width: 2px;
  transition:
    background 0.3s,
    border-color 0.3s;
}

.status[data-level='clean'] {
  border-color: var(--ok);
}

.status[data-level='elevated'] {
  border-color: var(--warn);
  background: color-mix(in srgb, var(--warn) 10%, var(--card));
}

.status[data-level='smoke'] {
  border-color: var(--bad);
  background: color-mix(in srgb, var(--bad) 14%, var(--card));
  animation: pulse 1s ease-in-out infinite;
}

@keyframes pulse {
  50% {
    box-shadow: 0 0 0 8px color-mix(in srgb, var(--bad) 25%, transparent);
  }
}

@media (prefers-reduced-motion: reduce) {
  .status[data-level='smoke'] {
    animation: none;
  }
}

.level {
  font-size: 22px;
  font-weight: 700;
}

.status[data-level='clean'] .level {
  color: var(--ok);
}

.status[data-level='elevated'] .level {
  color: var(--warn);
}

.status[data-level='smoke'] .level {
  color: var(--bad);
}

.reading {
  margin: 4px 0;
  font-size: 64px;
  font-weight: 800;
  line-height: 1.1;
  font-variant-numeric: tabular-nums;
}

.reading small {
  margin-left: 10px;
  color: var(--muted);
  font-size: 18px;
  font-weight: 500;
}

.detail {
  color: var(--muted);
  font-size: 14px;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  margin-top: 12px;
}

button,
select {
  min-height: 40px;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--card);
  color: var(--ink);
  font: inherit;
  font-size: 14px;
  cursor: pointer;
}

button[aria-pressed='true'],
.ranges .on {
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
}

.chart-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}

.ranges {
  display: flex;
  gap: 6px;
}

.ranges button {
  min-height: 34px;
  padding: 0 10px;
}

.chart-wrap {
  position: relative;
  height: 280px;
}

canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.tip {
  position: absolute;
  padding: 4px 8px;
  border-radius: 8px;
  background: #0f172a;
  color: #fff;
  font-size: 12px;
  pointer-events: none;
  transform: translate(-50%, -110%);
  white-space: nowrap;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 14px;
  color: var(--muted);
  font-size: 12px;
}

.legend i {
  display: inline-block;
  width: 18px;
  height: 3px;
  margin-right: -6px;
  border-radius: 2px;
}

.l-val {
  background: var(--accent);
}

.l-warn {
  background: var(--warn);
}

.l-alarm {
  background: var(--bad);
}

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.stats .card {
  padding: 12px;
}

.stats small {
  display: block;
  color: var(--muted);
  font-size: 12px;
}

.stats b {
  font-size: 22px;
  font-variant-numeric: tabular-nums;
}

.events {
  margin: 0;
  padding: 0;
  list-style: none;
}

.events li {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  padding: 6px 0;
  border-top: 1px solid var(--line);
  font-size: 14px;
}

.events li:first-child {
  border-top: 0;
}

.events .empty {
  color: var(--muted);
}

.note {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 14px;
}

.settings {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}

.settings label {
  display: grid;
  gap: 6px;
  font-size: 14px;
}

output {
  float: right;
  font-weight: 700;
}

input[type='range'] {
  width: 100%;
}

summary {
  cursor: pointer;
  font-weight: 600;
}

pre {
  overflow: auto;
  padding: 12px;
  border-radius: 10px;
  background: #0f172a;
  color: #e2e8f0;
  font-size: 12px;
}

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

.foot {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 600px) {
  .reading {
    font-size: 52px;
  }

  .stats {
    grid-template-columns: repeat(2, 1fr);
  }

  .chart-wrap {
    height: 230px;
  }
}