:root {
  --bg: #f4f5f7; --panel: #ffffff; --ink: #1d2330; --muted: #6b7280; --line: #dde1e7;
  --accent: #0f766e; --accent-ink: #ffffff; --live: #dc2626; --paper: #fffafa;
}
* { box-sizing: border-box; }
body { margin: 0; font: 14px/1.4 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; background: var(--bg); color: var(--ink); }
a { color: var(--accent); }
.mono { font-family: ui-monospace, "Cascadia Mono", Consolas, monospace; }
.muted { color: var(--muted); }
.small { font-size: 12px; }
.grow { flex: 1; }
button, .btn, select, input, textarea { font: inherit; }
button, .btn { border: 1px solid var(--line); background: var(--panel); color: var(--ink); border-radius: 6px; padding: 4px 10px; cursor: pointer; text-decoration: none; display: inline-block; }
button:hover, .btn:hover { border-color: var(--accent); }
button.on { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
select, input, textarea { border: 1px solid var(--line); border-radius: 6px; padding: 3px 6px; background: var(--panel); color: var(--ink); }

.top { display: flex; align-items: center; gap: 12px; padding: 8px 16px; background: var(--panel); border-bottom: 1px solid var(--line); flex-wrap: wrap; }
.brand { color: var(--accent); }
.badge { color: var(--live); font-weight: 600; font-size: 12px; }
.tools { display: flex; gap: 16px; flex-wrap: wrap; padding: 8px 16px; background: var(--panel); border-bottom: 1px solid var(--line); }
.grp { display: flex; gap: 6px; align-items: center; flex-wrap: wrap; }
.grp label { display: flex; align-items: center; gap: 4px; }

main { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 12px; padding: 12px 16px; }
@media (max-width: 900px) { main { grid-template-columns: minmax(0, 1fr); } }
.paper { background: var(--panel); border: 1px solid var(--line); border-radius: 8px; padding: 8px; min-width: 0; }
.nav { display: flex; gap: 6px; align-items: center; margin-bottom: 6px; }
.nav input[type=range] { flex: 1; }
canvas { display: block; width: 100%; background: var(--paper); border-radius: 4px; touch-action: none; }
.side { background: var(--panel); border: 1px solid var(--line); border-radius: 8px; padding: 8px 12px; display: flex; flex-direction: column; gap: 6px; }
.side h3 { margin: 10px 0 2px; font-size: 13px; }
.side label { display: flex; flex-direction: column; gap: 2px; }
.kv { border-collapse: collapse; width: 100%; font-variant-numeric: tabular-nums; }
.kv td, .kv th { padding: 2px 4px; border-bottom: 1px solid var(--line); text-align: right; }
.kv td:first-child, .kv th:first-child { text-align: left; color: var(--muted); }
#anns { list-style: none; padding: 0; margin: 0; max-height: 220px; overflow: auto; font-size: 12px; }
#anns li { display: flex; gap: 6px; padding: 2px 0; border-bottom: 1px solid var(--line); }
#anns li span:nth-child(2) { flex: 1; }
#anns li button { padding: 0 6px; }
.meta { font-size: 12px; color: var(--muted); }
#toast { position: fixed; bottom: 16px; left: 50%; transform: translateX(-50%); background: var(--ink); color: #fff; padding: 8px 14px; border-radius: 6px; }

.login { display: grid; place-items: center; min-height: 100vh; padding: 16px; }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 24px; width: min(360px, 100%); display: flex; flex-direction: column; gap: 12px; }
.card h1 { margin: 0; color: var(--accent); }
.card label { display: flex; flex-direction: column; gap: 4px; }
.card button { background: var(--accent); color: var(--accent-ink); border: 0; padding: 8px; }
.err { color: var(--live); margin: 0; }

.zoom { position: sticky; bottom: 0; z-index: 2; background: var(--panel); border-top: 2px solid var(--accent);
        box-shadow: 0 -6px 16px rgba(0,0,0,.08); padding-top: 6px; margin-top: 8px; max-height: 78vh; overflow: auto; }
.zoom .nav { flex-wrap: wrap; }
.zoom label { display: flex; align-items: center; gap: 4px; }
#anns li { cursor: pointer; }
.avg { margin-top: 8px; }
.avg canvas { background: #ffffff; }
.tools-z button { padding: 3px 8px; }
.tools-z { border-left: 1px solid var(--line); padding-left: 8px; }
/* cột số đo bám theo màn hình khi cuộn (đặt mốc ở khung phóng to vẫn thấy số đo để so sánh) */
.side { position: sticky; top: 8px; align-self: start; max-height: calc(100vh - 16px); overflow: auto; }
@media (max-width: 900px) { .side { position: static; max-height: none; } }
/* số đo ở cột phải: cùng kiểu với khung nhịp trung bình */
.kv td { padding: 4px 4px; }
.kv td:first-child { font-size: 13px; color: #64748b; }
.kv .val { font-size: 18px; font-weight: 700; font-variant-numeric: tabular-nums; }
.kv .unit { font-size: 11px; color: #94a3b8; font-weight: 400; }
.kv th { font-size: 13px; color: #1d2330; }