:root {
  --paper: #eceeef;
  --panel: #fbfbfa;
  --ink: #101418;
  --steel: #505c66;
  --rule: #788590;
  --rule-soft: #d3d8dc;
  --red: #d8001b;

  --red-soft: #fbe3e6;
  --teal: #08635f;
  --teal-soft: #dcefee;
  --amber: #7c4400;
  --amber-soft: #f7ead6;
  --sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --cond: "IBM Plex Sans Condensed", "IBM Plex Sans", system-ui, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}
* { box-sizing: border-box; }
html, body { margin: 0; background: var(--paper); color: var(--ink); font: 14px/1.5 var(--sans); }
body { min-height: 100vh; }
h1, h2, h3 { font-family: var(--cond); font-weight: 600; margin: 0; letter-spacing: .01em; }
button { font: inherit; cursor: pointer; }
:focus-visible { outline: 2px solid var(--ink); outline-offset: 2px; }
.mono { font-family: var(--mono); }
.num { font-family: var(--mono); font-variant-numeric: tabular-nums; }

/* ---------- header ---------- */
.top { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 12px 24px; border-bottom: 2px solid var(--ink); background: var(--panel); flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand b { font: 700 20px/1 var(--cond); letter-spacing: .18em; display: block; }
.brand span { font-size: 12px; color: var(--steel); }
.badges { display: flex; gap: 8px; flex-wrap: wrap; }
.badge { font: 500 11px/1 var(--mono); letter-spacing: .06em; padding: 7px 10px; border: 1px solid var(--ink); text-transform: uppercase; background: var(--panel); }
.badge.zero { background: var(--ink); color: var(--paper); }
.badge.hash { border-color: var(--rule); color: var(--steel); text-transform: none; }
.badge.live::before { content: ""; display: inline-block; width: 7px; height: 7px; background: var(--teal); border-radius: 50%; margin-right: 7px; }
.badge.rec::before { content: ""; display: inline-block; width: 7px; height: 7px; background: var(--red); border-radius: 50%; margin-right: 7px; }

/* ---------- shell ---------- */
.shell { display: grid; grid-template-columns: 208px minmax(0, 1fr) 340px; gap: 0; min-height: calc(100vh - 66px); }
.rail { border-right: 1px solid var(--rule); padding: 20px 16px; background: var(--paper); }
.rail h2, .ledger h2 { font-size: 13px; letter-spacing: .14em; text-transform: uppercase; color: var(--steel); font-weight: 600; }
#stations { list-style: none; margin: 14px 0; padding: 0; position: relative; }
#stations::before { content: ""; position: absolute; left: 13px; top: 14px; bottom: 14px; width: 2px; background: var(--rule); }
.st { position: relative; display: grid; grid-template-columns: 28px 1fr; gap: 10px; padding: 9px 0; align-items: start; }
.st .dot { width: 28px; height: 28px; border-radius: 50%; border: 2px solid var(--rule); background: var(--paper); display: grid; place-items: center; font: 600 12px var(--mono); color: var(--steel); z-index: 1; }
.st b { display: block; font: 600 14px/1.2 var(--cond); }
.st small { display: block; color: var(--steel); font-size: 12px; line-height: 1.3; margin-top: 2px; min-height: 16px; }
.st.running .dot { border-color: var(--ink); color: var(--ink); background: #fff; animation: pulse 1.1s infinite; }
.st.done .dot { border-color: var(--teal); background: var(--teal); color: #fff; }
.st.halt .dot { border-color: var(--red); background: var(--red); color: #fff; }
@keyframes pulse { 50% { box-shadow: 0 0 0 5px rgba(16,20,24,.12); } }
.rail-note { font-size: 12px; color: var(--steel); border-top: 1px solid var(--rule); padding-top: 12px; }

.work { min-width: 0; padding: 0 24px 40px; background: var(--paper); }
.tabs { display: flex; gap: 2px; border-bottom: 1px solid var(--rule); position: sticky; top: 0; background: var(--paper); z-index: 5; overflow-x: auto; }
.tab { border: 0; background: none; padding: 16px 14px 12px; font: 600 14px var(--cond); color: var(--steel); border-bottom: 3px solid transparent; white-space: nowrap; letter-spacing: .02em; }
.tab[aria-selected="true"] { color: var(--ink); border-bottom-color: var(--red); }
.tab:disabled { opacity: .38; cursor: not-allowed; }
.view { padding-top: 22px; }

/* ---------- primitives ---------- */
.card { background: var(--panel); border: 1px solid var(--rule); padding: 18px 20px; margin-bottom: 16px; }
.card h3 { font-size: 18px; margin-bottom: 4px; }
.sub { color: var(--steel); font-size: 13px; margin: 0 0 12px; max-width: 78ch; }
.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(330px, 1fr)); gap: 16px; }
.btn { border: 2px solid var(--ink); background: var(--ink); color: var(--paper); padding: 9px 16px; font: 600 14px var(--cond); letter-spacing: .04em; text-transform: uppercase; }
.btn:hover { background: #000; }
.btn.ghost { background: transparent; color: var(--ink); }
.btn.ghost:hover { background: var(--ink); color: var(--paper); }
.btn:disabled { opacity: .45; cursor: not-allowed; }
.pill { display: inline-block; font: 600 11px/1 var(--mono); letter-spacing: .05em; padding: 5px 7px; text-transform: uppercase; border: 1px solid; }
.pill.pass, .pill.OK, .pill.STABLE { color: var(--teal); background: var(--teal-soft); border-color: var(--teal); }
.pill.warn, .pill.WATCH { color: var(--amber); background: var(--amber-soft); border-color: var(--amber); }
.pill.fail, .pill.ALERT, .pill.RETRAIN { color: #fff; background: var(--red); border-color: var(--red); }
.pill.info { color: var(--steel); border-color: var(--rule); }
table { border-collapse: collapse; width: 100%; }
th { text-align: left; font: 600 11px var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--steel); padding: 8px 10px; border-bottom: 2px solid var(--ink); white-space: nowrap; }
td { padding: 9px 10px; border-bottom: 1px solid var(--rule-soft); vertical-align: top; }
table.mid td { vertical-align: middle; }
tr.clickable { cursor: pointer; }
tr.clickable:hover td { background: #fff; }
tr.sel td { background: #fff; box-shadow: inset 3px 0 0 var(--red); }
.kpis { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; margin-bottom: 16px; }
.kpi { background: var(--panel); border: 1px solid var(--rule); padding: 12px 14px; }
.kpi label { display: block; font: 500 11px var(--mono); letter-spacing: .07em; text-transform: uppercase; color: var(--steel); }
.kpi b { font: 600 26px/1.2 var(--mono); }
.kpi small { color: var(--steel); display: block; }
.empty { color: var(--steel); }
.bar { height: 10px; background: var(--rule-soft); position: relative; }
.bar > i { position: absolute; left: 0; top: 0; bottom: 0; background: var(--ink); }
.note { border-left: 3px solid var(--ink); background: #fff; padding: 10px 14px; font-size: 13px; margin: 12px 0; }
code, .code { font-family: var(--mono); font-size: 12.5px; background: #fff; border: 1px solid var(--rule); padding: 1px 5px; }
pre.code { padding: 12px 14px; overflow: auto; white-space: pre; }
.row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
select, input[type=text], input[type=file] { font: inherit; padding: 8px 10px; border: 1px solid var(--ink); background: #fff; }
input[type=range] { accent-color: var(--red); width: 220px; }
input[type=range].sim-slider { min-height: 28px; cursor: pointer; }
.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; width: 100%; margin-bottom: 8px; }


/* dataset cards */
.ds { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 14px; }
.dsc { background: var(--panel); border: 2px solid var(--rule); padding: 16px; text-align: left; display: block; width: 100%; }
.dsc[aria-pressed="true"] { border-color: var(--ink); box-shadow: 6px 6px 0 var(--ink); }
.dsc h3 { font-size: 18px; margin-bottom: 6px; }
.dsc p { margin: 0 0 10px; color: var(--steel); font-size: 13px; }
.dsc .meta { font: 500 12px var(--mono); color: var(--ink); }

/* ledger */
.ledger { border-left: 2px solid var(--ink); background: #f6f6f3; padding: 16px 0 24px; display: flex; flex-direction: column; max-height: calc(100vh - 66px); position: sticky; top: 0; align-self: start; }
.ledger-head { display: flex; justify-content: space-between; align-items: baseline; padding: 0 16px 10px; border-bottom: 1px dashed var(--steel); }
.ledger-head span { font: 500 11px var(--mono); color: var(--steel); }
.tape { overflow-y: auto; padding: 8px 16px; font: 400 12px/1.5 var(--mono); }
.tape .empty { font-family: var(--sans); font-size: 13px; }
.entry { padding: 7px 0 7px 12px; border-left: 3px solid var(--ink); margin: 7px 0; animation: feed .25s ease-out; }
.entry .tag { display: flex; gap: 8px; align-items: center; font-weight: 600; letter-spacing: .04em; }
.entry .tag i { font-style: normal; color: var(--steel); font-weight: 500; }
.entry .why { color: #2a3138; margin-top: 2px; word-break: break-word; }
.entry.node { border-left-color: var(--red); background: rgba(216,0,27,.05); }
@keyframes feed { from { opacity: 0; transform: translateY(-4px); } }

/* fleet + explanation */
.split { display: grid; grid-template-columns: minmax(300px, 420px) minmax(0, 1fr); gap: 16px; align-items: start; }
.sentence { font: 500 15px/1.55 var(--sans); border-left: 4px solid var(--red); padding: 4px 0 4px 14px; margin: 8px 0 14px; }
.sentence.ok { border-left-color: var(--teal); }
.wf { display: grid; grid-template-columns: minmax(140px, 1.3fr) 1.5fr 54px; gap: 6px 10px; align-items: center; font-size: 12.5px; }
.wf .axis { position: relative; height: 16px; background: linear-gradient(90deg, transparent calc(50% - 1px), var(--steel) calc(50% - 1px), var(--steel) calc(50% + 1px), transparent calc(50% + 1px)); }
.wf .axis i { position: absolute; top: 2px; bottom: 2px; }
.wf .axis i.up { background: var(--red); left: 50%; }
.wf .axis i.dn { background: var(--teal); right: 50%; }
svg text { font-family: var(--mono); font-size: 10px; fill: var(--steel); }
.legend { font-size: 12px; color: var(--steel); }
.spark-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 10px; }
.spark b { font: 500 11px var(--sans); display: block; margin-bottom: 2px; }

@media (max-width: 1180px) {
  .shell { grid-template-columns: 180px minmax(0, 1fr); }
  .ledger { grid-column: 1 / -1; position: static; max-height: 420px; border-left: 0; border-top: 2px solid var(--ink); }
}
@media (max-width: 760px) {
  .shell { grid-template-columns: 1fr; }
  .rail { border-right: 0; border-bottom: 1px solid var(--rule); }
  #stations { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0 12px; }
  #stations::before { display: none; }
  .work { padding: 0 16px 32px; }
  .top { padding: 12px 16px; }
  .split { grid-template-columns: 1fr; }
}
@media (prefers-reduced-motion: reduce) { * { animation: none !important; transition: none !important; } }

/* fleet: what-if and cost cards */
.whatif, .econ { margin-top: 16px; background: var(--paper); border: 1px solid var(--rule); padding: 14px; }
.whatif { border-color: var(--ink); }
.whatif h3, .econ h3 { font-size: 14px; margin: 0; letter-spacing: .02em; }
.whatif .sub, .econ .sub { margin: 2px 0 0; font-size: 12px; }
.whatif-head { display: flex; justify-content: space-between; align-items: flex-start; flex-wrap: wrap; gap: 8px; }
.whatif-head .btn { font-size: 11px; padding: 3px 8px; }
.sim-rows { margin-top: 12px; display: grid; gap: 8px; }
.sim-row { display: grid; grid-template-columns: minmax(140px, 1.4fr) 1.5fr minmax(96px, 1fr); gap: 8px; align-items: center; font-size: 12px; }
.sim-row input[type=range] { width: 100%; min-height: 28px; cursor: pointer; }
.sim-out { margin-top: 12px; padding-top: 10px; border-top: 1px dashed var(--rule); display: flex; justify-content: space-between; align-items: center; font-size: 12px; color: var(--steel); }
.sim-out b { font-size: 15px; color: var(--ink); }
.econ-inputs { margin-top: 10px; display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 12px; }
.econ-inputs label { font: 500 11px var(--mono); color: var(--steel); display: grid; gap: 4px; }
.econ-inputs input { font: inherit; padding: 6px 8px; border: 1px solid var(--ink); background: #fff; width: 100%; }
.econ-table { margin-top: 10px; }
.econ-table td:first-child { white-space: normal; }