/* Light-Speed Float — a night-time dashboard. Single dark theme on purpose. */
:root {
  color-scheme: dark;
  --ground: #080c11;
  --panel: #10171f;
  --line: #223142;
  --ink: #e8eef3;
  --muted: #8d9dac;
  --amber: #ffb000;
  --amber-soft: rgba(255, 176, 0, 0.14);
  --cyan: #48d2e4;
  --cyan-soft: rgba(72, 210, 228, 0.14);
  --red: #ff5a69;
  --green: #5fe08b;
  --display: "Chakra Petch", "Arial Narrow", system-ui, sans-serif;
  --body: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, Menlo, Consolas, monospace;
  --cell: clamp(30px, 8vw, 50px);
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { background: var(--ground); }
body { margin: 0; background: var(--ground); color: var(--ink); font: 17px/1.55 var(--body); }
button, input { font: inherit; color: inherit; }
b { font-weight: 600; }
.m { color: var(--amber); }
.e { color: var(--cyan); }
.neg { color: var(--red); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
:focus-visible { outline: 2px solid var(--cyan); outline-offset: 2px; }

.app {
  max-width: 760px;
  margin: 0 auto;
  padding-inline: 16px;
  padding-block: 28px 64px;
  display: grid;
  gap: 22px;
}
header { text-align: center; display: grid; gap: 6px; }
h1 { margin: 0; font: 700 clamp(32px, 6vw, 48px)/1 var(--display); }
.lede { margin: 0 auto; max-width: 46ch; color: var(--muted); text-wrap: balance; }

/* ---------- dial ---------- */
.dial-wrap { position: relative; width: 100%; max-width: 520px; margin: 0 auto; aspect-ratio: 400 / 340; }
#stars, #dial { position: absolute; inset: 0; width: 100%; height: 100%; }
#stars {
  -webkit-mask-image: radial-gradient(circle at 50% 56%, #000 50%, transparent 68%);
  mask-image: radial-gradient(circle at 50% 56%, #000 50%, transparent 68%);
}
#dial { overflow: visible; }
.d-face { fill: rgba(16, 23, 31, 0.6); }
.d-track { fill: none; stroke: var(--line); stroke-width: 14; }
.d-prog { fill: none; stroke: var(--amber); stroke-width: 14; filter: drop-shadow(0 0 6px rgba(255, 176, 0, 0.5)); }
.d-prog.rev { stroke: var(--red); filter: drop-shadow(0 0 6px rgba(255, 90, 105, 0.5)); }
.d-tick { stroke: var(--muted); stroke-width: 1.5; }
.d-icon { font-size: 22px; }
.d-light { fill: var(--red); font: 700 11px var(--display); letter-spacing: 0.08em; }
.d-needle { fill: var(--amber); }
.d-needle.rev { fill: var(--red); }
.d-hub { fill: #151f29; stroke: #2e4053; stroke-width: 2; }
.d-val { fill: var(--ink); font: 700 44px var(--display); }
.d-val.rev { fill: var(--red); }
.d-dir { fill: var(--muted); font: 600 12px var(--display); letter-spacing: 0.18em; }
.d-dir.rev { fill: var(--red); }

/* ---------- bits ---------- */
.bits { display: flex; flex-wrap: wrap; justify-content: center; gap: 16px 22px; }
.bitgroup { display: grid; gap: 6px; justify-items: center; }
.grp-label { font: 700 15px var(--display); letter-spacing: 0.06em; }
.grp-hint { font-size: 14px; color: var(--muted); margin-top: -4px; }
.cells { display: flex; align-items: flex-end; gap: clamp(3px, 1vw, 6px); }
.cell { display: grid; gap: 4px; justify-items: center; }
.pv { font: 500 clamp(9px, 2.5vw, 13px) var(--mono); color: var(--muted); white-space: nowrap; }
.pv.neg { color: var(--red); }
.bit {
  width: var(--cell);
  height: calc(var(--cell) * 1.2);
  border-radius: 10px;
  border: 2px solid var(--line);
  background: var(--panel);
  font: 700 clamp(18px, 4.8vw, 28px) var(--mono);
  cursor: pointer;
  transition: background-color 0.15s, border-color 0.15s;
}
.mant .bit { color: var(--amber); }
.exp .bit { color: var(--cyan); }
.mant .bit[aria-pressed="true"] { background: var(--amber-soft); border-color: var(--amber); }
.exp .bit[aria-pressed="true"] { background: var(--cyan-soft); border-color: var(--cyan); }
.bit:disabled { cursor: default; }
.pt { font: 700 34px/1 var(--mono); color: var(--amber); padding-bottom: 10px; margin-inline: -3px; }

/* ---------- buttons / quiz ---------- */
.actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; }
.btn {
  border: 1.5px solid var(--line);
  background: var(--panel);
  border-radius: 10px;
  padding: 9px 18px;
  font: 600 16px var(--display);
  cursor: pointer;
}
.btn:hover { border-color: var(--muted); }
.btn.primary { background: var(--amber); border-color: var(--amber); color: #1a1200; }
.quiz-intro { margin: 0; text-align: center; font: 600 18px/1.4 var(--display); text-wrap: balance; }
.ans-row { display: flex; flex-wrap: wrap; gap: 8px; }
.ans-row input {
  flex: 1 1 140px;
  min-width: 0;
  background: var(--ground);
  border: 1.5px solid var(--line);
  border-radius: 10px;
  padding: 8px 12px;
  font: 700 20px var(--mono);
}
.ans-row input:focus { border-color: var(--amber); outline: none; }
.msg { margin: 0; min-height: 1.55em; color: var(--muted); }
.msg.ok { color: var(--green); }
.msg.bad { color: var(--red); }

/* ---------- steps ---------- */
.steps { list-style: none; margin: 0; padding: 0; display: grid; gap: 14px; counter-reset: s; }
.step {
  counter-increment: s;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 16px 18px;
  display: grid;
  gap: 10px;
}
.step h2 { margin: 0; font: 700 19px/1.3 var(--display); display: flex; gap: 10px; align-items: center; }
.step h2::before {
  content: counter(s);
  flex: none;
  width: 30px; height: 30px;
  border-radius: 50%;
  background: var(--ink);
  color: var(--ground);
  display: grid; place-items: center;
  font-size: 16px;
}
.step p { margin: 0; }
.step.active { border-color: var(--amber); box-shadow: 0 0 0 1px var(--amber); }
.step.locked { opacity: 0.5; }
.step.locked h2::before { background: var(--line); color: var(--muted); }
.step.done h2::before { background: var(--green); }
.tag { font: 600 13px var(--display); padding: 1px 9px; border-radius: 999px; letter-spacing: 0.04em; }
.tag.ok { background: rgba(95, 224, 139, 0.15); color: var(--green); }
.tag.shown { background: var(--amber-soft); color: var(--amber); }
.finish { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; justify-content: space-between; padding: 4px 2px; }
.finish .msg { font: 600 18px var(--display); }
.note { color: var(--muted); font-size: 15px; }
.calc { font: 600 20px var(--mono); overflow-x: auto; }
.result { font: 700 30px var(--display); }

.tbl-wrap { overflow-x: auto; }
table { border-collapse: collapse; font-family: var(--mono); }
th, td { padding: 4px 10px; text-align: center; border: 1px solid var(--line); }
th { color: var(--muted); font-weight: 500; font-size: 13px; }
th.neg { color: var(--red); }
td { font-weight: 700; font-size: 20px; color: var(--amber); }
td.pad { color: var(--muted); font-style: italic; }
td.off { opacity: 0.35; }
.after-pt { border-left: 4px solid var(--ink); }

.shift { position: relative; display: inline-flex; padding: 4px 6px 4px; font: 700 26px var(--mono); }
.shift span { width: 26px; text-align: center; color: var(--amber); }
.shift span.pad { color: var(--muted); font-style: italic; }
.shift-pt {
  position: absolute; left: 6px; bottom: 8px;
  width: 9px; height: 9px; margin-left: -4.5px;
  border-radius: 50%; background: var(--ink); box-shadow: 0 0 10px var(--ink);
}
.shift-wrap { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; overflow-x: auto; }
.replay { font-size: 13px; padding: 4px 10px; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.001s !important; transition-duration: 0.001s !important; }
}

/* ---------- test: click where the point goes ---------- */
.slots-wrap { overflow-x: auto; padding-block: 4px; }
.slots { display: inline-flex; align-items: stretch; font: 700 26px/1 var(--mono); }
.slots .d { width: 24px; padding-block: 10px 18px; text-align: center; color: var(--amber); }
.slots .d.spare { color: var(--muted); opacity: 0.55; }
.gap {
  position: relative;
  width: 16px;
  border: 0;
  border-radius: 6px;
  background: transparent;
  cursor: pointer;
  padding: 0;
}
.gap:hover { background: rgba(232, 238, 243, 0.08); }
.gap::after {
  content: "";
  position: absolute;
  left: 50%; bottom: 14px;
  width: 9px; height: 9px;
  margin-left: -4.5px;
  border-radius: 50%;
  background: rgba(232, 238, 243, 0.14);
}
.gap:hover::after { background: rgba(232, 238, 243, 0.35); }
.gap.start::after { border: 1.5px solid var(--muted); background: transparent; }
.gap.on::after { background: var(--ink); border: 0; box-shadow: 0 0 10px var(--ink); }

/* ---------- test: click the place values ---------- */
table.pick th { padding: 3px; }
.pvbtn {
  min-width: 44px;
  border: 1.5px solid var(--line);
  background: var(--ground);
  border-radius: 8px;
  padding: 5px 6px;
  font: 600 13px var(--mono);
  color: var(--muted);
  cursor: pointer;
}
.pvbtn.neg { color: var(--red); }
.pvbtn:hover { border-color: var(--muted); }
.pvbtn.on { background: var(--amber); border-color: var(--amber); color: #1a1200; }
.pvbtn.neg.on { background: var(--red); border-color: var(--red); color: #1a0004; }

/* ---------- custom speed calculator ---------- */
.custom {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 16px 18px;
  display: grid;
  gap: 10px;
}
.custom h2 { margin: 0; font: 700 19px/1.3 var(--display); }
.custom .note { margin: 0; }
.custom-row { display: flex; flex-wrap: wrap; align-items: flex-end; gap: 10px 12px; }
.field { display: grid; gap: 4px; flex: 1 1 150px; min-width: 0; }
.efield { flex: 0 1 130px; }
.field span { font: 700 13px var(--display); letter-spacing: 0.06em; text-transform: uppercase; }
.mfield span { color: var(--amber); }
.efield span { color: var(--cyan); }
.field input {
  width: 100%;
  background: var(--ground);
  border: 1.5px solid var(--line);
  border-radius: 10px;
  padding: 8px 12px;
  font: 700 22px var(--mono);
  letter-spacing: 0.12em;
}
.mfield input { color: var(--amber); }
.efield input { color: var(--cyan); }
.mfield input:focus { border-color: var(--amber); outline: none; }
.efield input:focus { border-color: var(--cyan); outline: none; }
.custom-x { font: 700 20px var(--mono); color: var(--muted); padding-bottom: 10px; }
.msg.warn { color: var(--amber); }
@media (max-width: 480px) { .custom-x { display: none; } .efield { flex: 1 1 130px; } }

/* ---------- page links ---------- */
.pages { display: flex; justify-content: center; gap: 4px; padding: 4px; margin: 0 auto; background: var(--panel); border: 1px solid var(--line); border-radius: 999px; width: fit-content; max-width: 100%; }
.pages a { padding: 7px 16px; border-radius: 999px; font: 600 15px var(--display); color: var(--muted); text-decoration: none; }
.pages a:hover { color: var(--ink); }
.pages a[aria-current="page"] { background: var(--ink); color: var(--ground); }

/* ---------- normalising page ---------- */
.mono { font-family: var(--mono); }
.pos { color: var(--green); }
.arrow { color: var(--muted); font-size: 0.8em; margin-inline: 6px; }
.row { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.support, .target-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 16px 18px;
  display: grid;
  gap: 12px;
}
.support-head { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: baseline; gap: 8px; }
.support h2 { margin: 0; font: 700 19px/1.3 var(--display); }
.level-name { font: 700 15px var(--display); color: var(--amber); letter-spacing: 0.04em; }
.ladder { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 8px; }
.ladder li { border: 1.5px solid var(--amber); background: var(--amber-soft); border-radius: 10px; padding: 8px 10px; display: grid; gap: 2px; }
.ladder li b { font: 700 14px var(--display); }
.ladder li span { font-size: 13px; color: var(--muted); }
.ladder li.off { border: 1.5px dashed var(--line); background: transparent; }
.ladder li.off b { color: var(--muted); text-decoration: line-through; }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }
.target-label { margin: 0; font: 700 13px var(--display); letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); }
.target-val { font: 700 clamp(40px, 9vw, 56px)/1 var(--display); color: var(--ink); }
.target-val.neg { color: var(--red); }
.own { display: flex; flex: 1 1 260px; gap: 8px; min-width: 0; }
.own input, input.typed {
  flex: 1 1 140px;
  min-width: 0;
  background: var(--ground);
  border: 1.5px solid var(--line);
  border-radius: 10px;
  padding: 8px 12px;
  font: 700 18px var(--mono);
}
.own input:focus, input.typed:focus { border-color: var(--amber); outline: none; }
.hint { background: var(--cyan-soft); border-left: 3px solid var(--cyan); border-radius: 6px; padding: 8px 12px; font-size: 15px; }
.helper { color: var(--muted); }
.helper b { color: var(--ink); }
h2.solo::before { display: none; }
.steps.solo-mode { counter-reset: none; }

.builder-wrap { overflow-x: auto; padding-bottom: 2px; }
.builder, .ebits { display: inline-flex; gap: 3px; }
.colbtn {
  display: grid;
  gap: 2px;
  justify-items: center;
  min-width: clamp(29px, 8vw, 42px);
  padding: 5px 2px 6px;
  border: 1.5px solid var(--line);
  border-radius: 8px;
  background: var(--ground);
  cursor: pointer;
}
.colbtn span { font: 500 clamp(9px, 2.6vw, 12px) var(--mono); color: var(--muted); }
.colbtn b { font: 700 22px var(--mono); color: var(--amber); opacity: 0.4; }
.colbtn.on { border-color: var(--amber); background: var(--amber-soft); }
.colbtn.on b { opacity: 1; }
.colbtn.e b { color: var(--cyan); }
.colbtn.e.on { border-color: var(--cyan); background: var(--cyan-soft); }
.colbtn.negcol span { color: var(--red); }
.colbtn.first-frac { margin-left: 12px; position: relative; }
.colbtn.first-frac::before { content: "."; position: absolute; left: -12px; bottom: 4px; font: 700 26px var(--mono); color: var(--ink); }
.slots .d.spare { color: var(--muted); opacity: 0.45; }