:root {
  color-scheme: light;
  --ink: #18313f;
  --muted: #536873;
  --paper: #f4f6f5;
  --line: #dce4e5;
  --return: #9a6515;
  --exhaust: #b84b53;
  --oa: #157b70;
  --supply: #3069ad;
  --pos: #176344;
  --neg: #245a9f;
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 16px/1.55 system-ui, -apple-system, "Segoe UI", sans-serif; }
main { max-width: 1480px; margin: auto; padding: 38px 32px 28px; }
header { max-width: 1040px; margin-bottom: 24px; }
.eyebrow { display: flex; align-items: center; gap: 16px; color: var(--oa); font-size: 11px; letter-spacing: 1.8px; text-transform: uppercase; font-weight: 750; }
.eyebrow span { color: var(--muted); border-left: 1px solid #bacdc7; padding-left: 16px; font-weight: 500; }
h1 { font-size: clamp(30px, 3.5vw, 46px); line-height: 1.15; letter-spacing: -1.6px; margin: 12px 0; }
header p { font-size: 17px; color: var(--muted); margin: 0; max-width: 900px; }
header strong, .lead strong { color: var(--ink); font-weight: 650; }
h3 { letter-spacing: -.3px; }

/* ---- controls ---- */
.control-deck { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.controls, .pressure-controls { min-width: 0; border-radius: 12px; padding: 20px 24px; }
.controls { background: var(--ink); color: #fff; border: 1px solid var(--ink); }
.pressure-controls { background: #e9f0ed; border: 1px solid #d1ded8; }
.slider-title { display: flex; justify-content: space-between; align-items: center; gap: 12px; font-size: 15px; font-weight: 650; line-height: 1.3; }
.slider-title small { display: block; font-size: 12px; font-weight: 400; opacity: .75; margin-top: 4px; }
.slider-title output { font-size: 26px; white-space: nowrap; font-variant-numeric: tabular-nums; letter-spacing: -.7px; }
input[type=range] { width: 100%; margin: 15px 0 6px; height: 20px; accent-color: #83dcc6; cursor: pointer; }
.pressure-controls input { accent-color: var(--oa); }
.range-ends { display: flex; justify-content: space-between; gap: 12px; font-size: 11px; color: #c5d4db; }
.pressure-controls .range-ends { color: var(--muted); }
button { font: inherit; font-size: 12px; font-weight: 650; border: 1px solid #c4d1d5; background: white; color: var(--ink); border-radius: 6px; padding: 8px 12px; min-height: 36px; cursor: pointer; transition: background .15s; }
button:hover { background: #e7efed; }
button[aria-pressed=true] { background: #dceee7; border-color: #91bbae; }
button:focus-visible, input:focus-visible, summary:focus-visible, .schematic-scroll:focus-visible, a:focus-visible { outline: 3px solid #d69325; outline-offset: 3px; }
.controls button { background: transparent; color: #d8e5e9; border-color: #607a86; }
.controls button:hover, .controls button[aria-pressed=true] { background: #e0f5ed; color: #173f37; border-color: #e0f5ed; }
.pressure-controls button { background: transparent; border-color: #a8bfb5; }
.pressure-controls button:hover, .pressure-controls button[aria-pressed=true] { background: #cce3d9; border-color: #81ae9d; }
.buttons { display: flex; gap: 7px; flex-wrap: wrap; }
.presets { margin-top: 16px; }
.transport { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px; padding: 14px 0; }
.transport p { font-size: 12px; color: var(--muted); margin: 0; }
.duct-loss-equation { background: #edf1f0; border-radius: 7px; margin: 0; padding: 10px 14px; font-size: 12px; color: var(--muted); font-variant-numeric: tabular-nums; }
.duct-loss-equation strong { color: var(--ink); margin-right: 6px; }
.pressure-key { display: flex; flex-wrap: wrap; gap: 5px 7px; font-size: 12px; color: var(--muted); margin: 18px 0 0; }
.pressure-key strong { color: var(--ink); }
.gauge-key { white-space: nowrap; padding: 1px 6px; border-radius: 4px; font-size: 11px; }
.positive-key { background: #e7f2eb; color: #216246; }
.negative-key { background: #e8f0fa; color: #285f9d; }
.legend { display: flex; flex-wrap: wrap; gap: 12px 22px; margin: 16px 0 14px; font-size: 12px; color: var(--muted); }
.legend span::before { content: ''; display: inline-block; width: 19px; height: 3px; background: var(--color); vertical-align: middle; margin-right: 7px; border-radius: 2px; }
.legend span:last-child::before { display: none; }
.print-note { display: none; }
.no-script { padding: 14px; background: #fff3d8; border: 1px solid #dbbe8b; }

/* ---- cards ---- */
.compare { display: grid; grid-template-columns: 1fr 1fr; align-items: start; gap: 20px; }
.card { min-width: 0; background: #fff; border: 1px solid var(--line); border-top: 4px solid var(--return); border-radius: 12px; overflow: hidden; box-shadow: 0 3px 10px #18313f08; }
.exhaust-card { border-top-color: var(--exhaust); }
.card-head { padding: 20px 22px 2px; }
.card h2 { display: flex; align-items: center; gap: 10px; font-size: 23px; line-height: 1.3; letter-spacing: -.5px; margin: 0 0 6px; }
.card-index { font-size: 11px; letter-spacing: .4px; color: var(--return); background: #f8f0e3; border-radius: 5px; padding: 6px 7px; }
.exhaust-card .card-index { color: var(--exhaust); background: #faecee; }
.card-head p { margin: 0; font-size: 13px; color: var(--muted); }
.card-head p strong { color: var(--ink); }
.schematic-scroll { overflow-x: auto; overscroll-behavior-x: contain; scrollbar-width: thin; scrollbar-color: #b7c9c6 transparent; }
.diagram { width: 100%; height: auto; display: block; }
.scroll-hint { display: none; }

/* ---- schematic ---- */
svg text { font-family: system-ui, -apple-system, "Segoe UI", sans-serif; font-size: 13px; fill: var(--ink); }
svg .small { font-size: 11px; fill: var(--muted); }
svg .zone-label { font-size: 9.5px; letter-spacing: .8px; fill: var(--muted); font-weight: 650; }
svg .room-label { font-size: 12px; fill: var(--muted); }
svg .amount { font-size: 14px; font-weight: 700; }
svg .diagram-note { font-size: 10px; fill: var(--muted); }
svg .zone-outdoors { fill: #eaf4f1; }
svg .ahu-envelope { fill: #fbfdfd; stroke: #c6d5d8; stroke-dasharray: 5 4; stroke-width: 1.2; }
svg .room-envelope { fill: #eef3f6; stroke: #d9e2e8; }
svg .plenum { fill: rgba(48,105,173,.08); transition: fill .2s; }
svg .duct { fill: none; stroke: #e6ecee; stroke-width: 24; stroke-linejoin: round; stroke-linecap: butt; }
svg .flow { fill: none; stroke-width: 3; stroke-dasharray: 7 9; stroke-linecap: round; }
svg .flow.closed { stroke: #a8b6bd; stroke-dasharray: 2 7; stroke-width: 2 !important; }
svg .arrow { stroke: none; transition: opacity .2s; }
svg .node { fill: var(--ink); }
svg .fan-halo { fill: white; }
svg .fan-casing { fill: white; stroke: var(--fan-color); stroke-width: 2; }
svg .fan-hub, svg .rotor path { fill: var(--fan-color); }
svg .rotor { transform-box: fill-box; transform-origin: center; }
svg .fan-name { font-size: 12px; font-weight: 650; }
svg .fan.stopped .rotor path, svg .fan.stopped .fan-hub { fill: #b9c4c9; }
svg .fan.stopped .fan-casing { stroke: #b9c4c9; }
svg .fan-off-badge { opacity: 0; transition: opacity .2s; }
svg .fan.stopped .fan-off-badge { opacity: 1; }
svg .fan-off-badge rect { fill: #18313f; }
svg .fan-off-badge text { fill: white; font-size: 9px; font-weight: 750; letter-spacing: .5px; }
svg .damper line { stroke: #4f6a78; stroke-width: 3; stroke-linecap: round; }
svg .damper.closed line { stroke: #2f4654; stroke-width: 3.6; }
svg .damper-pivot { fill: #2f4654; }
svg .damper-pct { font-weight: 650; fill: var(--ink); }
svg .louver rect { fill: #f2f6f7; stroke: #9fb0b8; stroke-width: 1; }
svg .louver path { stroke: #9fb0b8; stroke-width: 1.2; }
svg .filter { fill: #e1e8ed; stroke: #8ca0ae; }
svg .filter-lines { stroke: #8ca0ae; stroke-width: 1; }
svg .leak-line { fill: none; stroke: var(--exhaust); stroke-width: 1.5; }
svg .leak-arrow { fill: var(--exhaust); }
svg .rise rect { fill: white; stroke: #d5dfe2; }
svg .rise text { font-size: 11.5px; font-weight: 700; font-variant-numeric: tabular-nums; }
svg .chip rect { fill: #e8f0fa; stroke: #c7d6e8; }
svg .chip text { font-size: 11.5px; font-weight: 700; fill: var(--neg); font-variant-numeric: tabular-nums; }
svg .chip.positive rect { fill: #e7f2eb; stroke: #bcd7c6; }
svg .chip.positive text { fill: var(--pos); }
svg .chip-letter { fill: var(--ink); font-weight: 800; }
.paused .flow { animation: none; }

/* ---- card text panels ---- */
.reading { margin: 0 20px 18px; padding: 12px 14px; background: #f3f6f6; border: 1px solid #e6eded; border-radius: 8px; min-height: 82px; font-size: 13px; color: var(--muted); }
.reading strong { display: block; color: var(--ink); font-size: 18px; margin-bottom: 3px; }
.pressure-panel { padding: 0 20px 20px; }
.pressure-heading { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: baseline; gap: 4px; margin: 0 0 12px; }
.pressure-heading h3 { font-size: 15px; margin: 0; font-weight: 650; }
.pressure-heading span { font-size: 10px; color: var(--muted); }
.pressure-stations { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 6px; }
.station { border-radius: 7px; padding: 8px 8px; background: #edf3fa; border: 1px solid #dbe5f1; min-width: 0; }
.station.positive { background: #edf5f0; border-color: #d9e8df; }
.station > span { font-size: 9.5px; display: flex; align-items: center; gap: 4px; min-height: 26px; line-height: 1.25; color: var(--muted); }
.station b { display: inline-grid; place-items: center; flex-shrink: 0; width: 15px; height: 15px; border-radius: 50%; background: var(--ink); color: white; font-size: 8.5px; }
.station strong { display: block; font-size: 18px; line-height: 1.3; font-variant-numeric: tabular-nums; letter-spacing: -.5px; }
.station.negative strong { color: var(--neg); }
.station.positive strong { color: var(--pos); }
.pressure-duty { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin: 14px 0 12px; }
.duty-row { font-size: 11px; }
.duty-row > span { display: block; color: var(--muted); }
.duty-row strong { display: block; font-size: 21px; margin-top: 3px; font-variant-numeric: tabular-nums; }
.duty-row.off strong { color: var(--muted); }
.duty-row small { font-size: 10px; font-weight: 400; color: var(--muted); }
.duty-track { height: 5px; border-radius: 4px; overflow: hidden; background: #edf1f2; margin-top: 6px; }
.duty-track i { display: block; height: 100%; }
.pressure-story, .relief-budget { font-size: 13px; line-height: 1.55; margin: 12px 0 0; }
.pressure-story { min-height: 120px; }
.pressure-story > strong, .relief-budget > strong { display: block; margin-bottom: 5px; }
.relief-budget { padding: 12px 14px; border: 1px solid #e9e1d6; background: #fcfaf6; border-radius: 7px; min-height: 104px; }

/* ---- pressure profile ---- */
.profile-section { margin-top: 22px; background: white; border: 1px solid var(--line); border-radius: 12px; padding: 22px 24px 18px; }
.profile-head h3 { margin: 0 0 6px; font-size: 22px; letter-spacing: -.5px; }
.profile-head p { margin: 0; font-size: 14px; color: var(--muted); max-width: 980px; }
.profile-legend { display: flex; flex-wrap: wrap; gap: 8px 22px; margin: 14px 0 4px; font-size: 12px; color: var(--muted); }
.profile-legend span::before { content: ''; display: inline-block; width: 22px; height: 0; border-top: 3px solid; vertical-align: middle; margin-right: 8px; }
.lg-return::before { border-color: var(--return); }
.lg-exhaust::before { border-color: var(--exhaust); }
.lg-branch::before { border-top-style: dashed; border-color: #7f929c; }
.lg-gap::before { height: 10px; border: 0 !important; background: rgba(154,101,21,.14); }
.profile-scroll { overflow-x: auto; }
.profile-chart { width: 100%; height: auto; display: block; min-width: 720px; }
.pf-grid { stroke: #edf1f3; stroke-width: 1; }
.pf-grid.zero { stroke: #7f929c; stroke-width: 1.4; stroke-dasharray: 5 4; }
.pf-tick, .pf-axis, .pf-zero-label { font-size: 11px; fill: var(--muted); font-variant-numeric: tabular-nums; }
.pf-zero-label { font-weight: 650; }
.pf-fanline { stroke: #f2f5f6; stroke-width: 14; }
.pf-fanmark { font-size: 10px; fill: #97a7ae; font-style: italic; }
.pf-gap { fill: rgba(154,101,21,.13); stroke: none; }
.pf-line { fill: none; stroke-width: 3.4; stroke-linejoin: round; stroke-linecap: round; }
.pf-line.r { stroke: var(--return); }
.pf-line.e { stroke: var(--exhaust); stroke-width: 2.8; }
.pf-line.recirc.closed { stroke-dasharray: 2 6; opacity: .45; stroke-width: 2; }
.pf-branch { stroke: #7f929c; stroke-dasharray: 4 4; }
.pf-branch.r { stroke: var(--return); opacity: .7; }
.pf-branch.e { stroke: var(--exhaust); opacity: .7; }
.pf-branch-fan { stroke: var(--exhaust); }
.pf-branch-label { font-size: 10.5px; fill: var(--muted); font-style: italic; }
.pf-pt { stroke: white; stroke-width: 2; }
.pf-pt.r { fill: var(--return); }
.pf-pt.e { fill: var(--exhaust); }
.pf-pt.shared { fill: var(--ink); }
.pf-val { font-size: 11.5px; font-weight: 700; paint-order: stroke; stroke: white; stroke-width: 4px; stroke-linejoin: round; font-variant-numeric: tabular-nums; }
.pf-val.r { fill: var(--return); }
.pf-val.e { fill: var(--exhaust); }
.pf-val.shared { fill: var(--ink); }
.pf-loss { font-size: 10.5px; fill: var(--muted); paint-order: stroke; stroke: white; stroke-width: 4px; }
.pf-fan-label { font-size: 12px; font-weight: 750; paint-order: stroke; stroke: white; stroke-width: 4px; }
.pf-fan-label.r { fill: var(--return); }
.pf-fan-label.e { fill: var(--exhaust); }
.pf-delta line { stroke: var(--supply); stroke-width: 2; }
.pf-delta path { fill: none; stroke: var(--supply); stroke-width: 2; }
.pf-delta text { font-size: 11px; fill: var(--supply); paint-order: stroke; stroke: white; stroke-width: 4px; }
.pf-delta-val { font-size: 13px; font-weight: 800; }
.pf-station circle { fill: var(--ink); }
.pf-station text { fill: white; font-size: 10px; font-weight: 800; }
.pf-station-name { font-size: 10.5px; fill: var(--muted); }
.profile-notes { margin: 8px 0 0; padding-left: 20px; font-size: 14px; color: var(--muted); }
.profile-notes li { margin: 6px 0; }
.profile-notes b { color: var(--ink); }

/* ---- compare tiles ---- */
.compare-strip { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; margin-top: 18px; }
.tile { background: #f7f9f9; border: 1px solid #e3eaec; border-radius: 9px; padding: 12px 14px; font-size: 12px; min-width: 0; }
.tile-label { display: block; color: var(--muted); font-size: 11px; margin-bottom: 8px; }
.tile-row { display: flex; justify-content: space-between; align-items: baseline; gap: 6px; }
.tile-row em { font-style: normal; color: var(--muted); font-size: 11px; }
.tile-row strong { font-size: 19px; font-variant-numeric: tabular-nums; letter-spacing: -.4px; }
.tile-row strong small { font-size: 10px; color: var(--muted); font-weight: 500; }
.tile-bar { height: 5px; background: #e6ecee; border-radius: 4px; overflow: hidden; margin: 3px 0 8px; }
.tile-bar i { display: block; height: 100%; }
.tile-delta { display: inline-block; font-size: 11px; font-weight: 650; padding: 2px 7px; border-radius: 4px; background: #eef1f2; color: var(--muted); }
.tile-delta.more { background: #faecee; color: #8f2f37; }
.tile-delta.less { background: #e7f2eb; color: #216246; }

/* ---- notice / takeaways ---- */
.notice { background: #e6f1ed; border-left: 4px solid var(--oa); border-radius: 0 10px 10px 0; padding: 16px 22px; margin-top: 18px; }
.notice h3 { margin: 0 0 6px; font-size: 16px; }
.notice ul { margin: 0; padding-left: 20px; font-size: 14.5px; }
.notice li { margin: 6px 0; }
.pressure-footnote { font-size: 11px; color: var(--muted); margin: 10px 0; }

/* ---- worksheet ---- */
.worksheet { margin-top: 26px; background: white; border: 1px solid var(--line); border-radius: 12px; padding: 22px 24px; }
.worksheet h3 { margin: 0 0 6px; font-size: 20px; }
.worksheet > p { font-size: 13.5px; color: var(--muted); margin: 0 0 14px; max-width: 1000px; }
.worksheet table { width: 100%; border-collapse: collapse; font-size: 13px; }
.worksheet th, .worksheet td { text-align: left; vertical-align: top; padding: 10px 12px; border-top: 1px solid var(--line); }
.worksheet th { font-size: 12px; color: var(--muted); font-weight: 650; }
.worksheet thead th { border-top: 0; padding-top: 0; }
.worksheet thead th.r { color: var(--return); }
.worksheet thead th.e { color: var(--exhaust); }
.worksheet td b { font-size: 15px; }
.worksheet td small { display: block; color: var(--muted); font-size: 11.5px; margin-top: 4px; }
.worksheet .ws-note { font-size: 12px; color: var(--muted); margin: 12px 0 0; }

/* ---- spectrum ---- */
.spectrum { margin-top: 26px; }
.spectrum h3 { margin: 0 0 4px; font-size: 20px; }
.spectrum > p { margin: 0 0 12px; font-size: 13.5px; color: var(--muted); }
.spectrum-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.spectrum article { background: white; border: 1px solid var(--line); border-radius: 10px; padding: 16px 18px; border-top: 4px solid #9fb0b8; }
.spectrum article:nth-child(2) { border-top-color: var(--exhaust); }
.spectrum article:nth-child(3) { border-top-color: var(--return); }
.spectrum h4 { margin: 0 0 6px; font-size: 15px; }
.spectrum h4 small { display: block; font-weight: 500; color: var(--muted); font-size: 11px; letter-spacing: .3px; text-transform: uppercase; margin-bottom: 4px; }
.spectrum p { margin: 6px 0; font-size: 13px; }
.spectrum .rule { display: inline-block; margin-top: 6px; font-size: 11.5px; font-weight: 650; color: var(--ink); background: #f1f4f5; padding: 3px 8px; border-radius: 4px; }

/* ---- why sections ---- */
.selection { margin-top: 20px; display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.selection article { padding: 20px 22px; border: 1px solid var(--line); border-radius: 10px; background: white; }
.selection h3 { margin: 0 0 10px; font-size: 18px; }
.selection p { font-size: 14px; margin: 8px 0; }
.return-static { margin-top: 20px; background: #fff8ec; border: 1px solid #ecd9b3; border-left: 5px solid var(--return); border-radius: 10px; padding: 22px 24px; }
.return-static h3 { margin: 0 0 8px; font-size: 20px; }
.return-static p { font-size: 14px; margin: 8px 0; max-width: 1080px; }
.return-static ul { font-size: 13.5px; margin: 8px 0 0; padding-left: 20px; max-width: 1080px; }
.return-static li { margin: 5px 0; }

/* ---- balance, explainer ---- */
.balance { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; margin-top: 26px; padding: 24px 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.balance h3 { margin: 0 0 10px; font-size: 17px; }
.balance p { margin: 8px 0; font-size: 14px; }
.equation { font-variant-numeric: tabular-nums; background: white; padding: 12px 14px; border-radius: 7px; font-size: 13px; }
.oa-explainer { background: white; border: 1px solid var(--line); border-radius: 12px; padding: 24px; margin-top: 26px; }
.oa-explainer h3 { margin: 0 0 12px; font-size: 22px; letter-spacing: -.5px; }
.oa-explainer h4 { font-size: 16px; margin: 0 0 8px; }
.oa-explainer p { font-size: 14px; line-height: 1.65; }
.oa-explainer-columns { display: grid; grid-template-columns: 1fr 1fr; gap: 30px; margin-top: 22px; }
.oa-explainer .equation { background: #eef3f8; font-size: 13px; }
details { margin-top: 24px; border-top: 1px solid var(--line); padding-top: 18px; font-size: 13px; color: var(--muted); }
summary { cursor: pointer; font-weight: 650; color: var(--ink); }
details p, details li { max-width: 1120px; }
details li { margin: 8px 0; }
footer { font-size: 11px; color: var(--muted); margin-top: 24px; line-height: 1.7; }
footer p { margin: 4px 0; }
a { color: #146879; text-underline-offset: 2px; }

/* ---- responsive ---- */
@media (max-width: 1180px) {
  .compare { grid-template-columns: 1fr; }
  .compare-strip { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .pressure-story, .relief-budget { min-height: 0; }
}
@media (max-width: 900px) {
  .spectrum-grid { grid-template-columns: 1fr; }
}
@media (max-width: 760px) {
  main { padding: 24px 16px; }
  header p { font-size: 15px; }
  .control-deck, .balance, .selection, .oa-explainer-columns { grid-template-columns: 1fr; }
  .controls, .pressure-controls { padding: 18px; }
  .slider-title { font-size: 14px; }
  .slider-title output { font-size: 23px; }
  .transport { align-items: flex-start; }
  .transport .buttons { width: 100%; }
  .transport button { flex: 1; }
  .diagram { min-width: 640px; }
  .scroll-hint { display: block; font-size: 11px; margin: 0 20px 12px; color: var(--muted); }
  .eyebrow { gap: 10px; font-size: 9px; letter-spacing: 1px; }
  .eyebrow span { padding-left: 10px; }
  .pressure-stations { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .oa-explainer-columns { gap: 10px; }
  .oa-explainer { padding: 18px; }
  .oa-explainer h3 { font-size: 20px; }
  .worksheet { overflow-x: auto; }
  .worksheet table { min-width: 640px; }
}
@media (max-width: 430px) {
  .pressure-stations { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .pressure-panel { padding: 0 16px 16px; }
  .pressure-duty { gap: 12px; }
  .compare-strip { grid-template-columns: 1fr; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}

/* ---- print ---- */
@media print {
  @page { size: 17in 11in; margin: 11mm; }
  * { print-color-adjust: exact; -webkit-print-color-adjust: exact; }
  body { background: white; font-size: 12px; }
  main { max-width: none; padding: 0; }
  header { max-width: none; margin-bottom: 10px; }
  header p { max-width: none; font-size: 13px; }
  h1 { font-size: 28px; margin: 8px 0; }
  .control-deck, .transport, .duct-loss-equation, .scroll-hint { display: none; }
  .print-note { display: block; font-size: 11px; margin: 8px 0; }
  .pressure-key { font-size: 10px; margin: 8px 0; }
  .gauge-key { font-size: 10px; }
  .legend { margin: 8px 0 12px; font-size: 11px; }
  .compare, .balance, .selection { grid-template-columns: 1fr 1fr; }
  .compare { gap: 16px; }
  .card { break-inside: auto; box-shadow: none; }
  .card-head, .schematic-scroll, .reading, .pressure-stations, .pressure-duty, .pressure-story, .relief-budget, .compare-strip, .tile { break-inside: avoid; }
  .card-head { padding: 8px 16px 0; }
  .card h2 { font-size: 18px; margin-bottom: 2px; }
  .card-head p { font-size: 11px; }
  .card .diagram { min-width: 0; max-height: 2.8in; }
  .schematic-scroll { overflow: visible; }
  .reading { margin: 0 16px 8px; padding: 6px 10px; min-height: 0; font-size: 11px; }
  .reading strong { font-size: 15px; }
  .pressure-panel { padding: 0 16px 12px; }
  .pressure-heading { margin-bottom: 7px; }
  .pressure-heading h3 { font-size: 13px; }
  .station { padding: 5px 7px; }
  .station > span { min-height: 17px; }
  .station strong { font-size: 16px; }
  .pressure-duty { margin: 8px 0; }
  .duty-row strong { font-size: 17px; }
  .pressure-story, .relief-budget { min-height: 0; font-size: 10px; line-height: 1.4; margin-top: 6px; }
  .relief-budget { padding: 6px 10px; }
  .pressure-panel { padding-bottom: 8px; }
  header { margin-bottom: 6px; }
  h1 { margin: 6px 0; }
  .profile-section { break-inside: avoid; margin-top: 14px; padding: 14px 16px; }
  .profile-head h3 { font-size: 18px; }
  .profile-head p, .profile-notes { font-size: 11px; }
  .profile-chart { min-width: 0; }
  /* Stroked text prints as two glyph layers and garbles copy/paste from the PDF; print it plain. */
  .pf-val, .pf-loss, .pf-fan-label, .pf-delta text { paint-order: normal; stroke: none; }
  .compare-strip { grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; }
  .tile-row strong { font-size: 16px; }
  .notice { padding: 10px 16px; margin-top: 12px; break-inside: avoid; }
  .notice ul { font-size: 12px; }
  .pressure-footnote { font-size: 9px; }
  .worksheet { break-inside: avoid; margin-top: 14px; padding: 14px 16px; }
  .worksheet table { font-size: 11px; }
  .worksheet td b { font-size: 13px; }
  .spectrum { break-inside: avoid; margin-top: 14px; }
  .spectrum-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 10px; }
  .spectrum p { font-size: 11px; }
  .selection { margin-top: 14px; break-inside: avoid; }
  .selection article { padding: 12px 16px; }
  .selection h3 { font-size: 16px; }
  .selection p { font-size: 12px; }
  .return-static { break-inside: avoid; margin-top: 14px; padding: 14px 16px; }
  .return-static p, .return-static ul { font-size: 12px; }
  .balance { margin-top: 14px; padding: 14px 0; break-inside: avoid; }
  .balance p { font-size: 12px; }
  .oa-explainer { margin-top: 14px; padding: 14px 16px; break-inside: avoid; }
  .oa-explainer h3 { font-size: 18px; }
  .oa-explainer h4 { font-size: 14px; }
  .oa-explainer p { font-size: 12px; margin: 8px 0; line-height: 1.45; }
  .oa-explainer-columns { grid-template-columns: 1fr 1fr; gap: 24px; margin-top: 14px; }
  .oa-explainer .equation { font-size: 12px; }
  details { font-size: 10.5px; margin-top: 12px; padding-top: 10px; }
  details p, details li { margin: 4px 0; }
  summary { list-style: none; }
  footer { font-size: 9px; margin-top: 8px; line-height: 1.5; }
  footer p { margin: 2px 0; }
}