:root {
  --acid: #d9ff43;
  --acid-soft: rgba(217, 255, 67, 0.12);
  --black: #090b0a;
  --charcoal: #101311;
  --charcoal-light: #171b18;
  --cream: #e9e8dd;
  --cyan: #57d8ff;
  --muted: #8d948a;
  --red: #ff5a48;
  --line: rgba(233, 232, 221, 0.14);
  --mono: 'IBM Plex Mono', Consolas, monospace;
  --display: 'Barlow Condensed', Impact, sans-serif;
}

* { box-sizing: border-box; }

html { color-scheme: dark; }

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  color: var(--cream);
  background:
    radial-gradient(circle at 83% 12%, rgba(217, 255, 67, 0.055), transparent 25rem),
    linear-gradient(135deg, #0c0f0d 0%, var(--black) 52%, #0c0e0d 100%);
  font-family: var(--mono);
}

button, input { font: inherit; }

button { color: inherit; }

button:focus-visible, input:focus-visible {
  outline: 2px solid var(--acid);
  outline-offset: 3px;
}

.noise {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 20;
  opacity: .12;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.18'/%3E%3C/svg%3E");
}

.site-header, main, footer {
  width: min(1180px, calc(100% - 48px));
  margin-inline: auto;
}

.site-header {
  height: 92px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: flex;
  gap: 13px;
  align-items: center;
  color: var(--cream);
  text-decoration: none;
}

.brand svg {
  width: 40px;
  fill: none;
  stroke: var(--acid);
  stroke-width: 1.5;
}

.brand span { display: grid; gap: 2px; }
.brand strong { font-family: var(--display); font-size: 21px; letter-spacing: .11em; line-height: 1; }
.brand small { color: var(--muted); font-size: 9px; letter-spacing: .18em; text-transform: uppercase; }

.header-meta {
  display: flex;
  gap: 10px;
  align-items: center;
  color: var(--muted);
  font-size: 10px;
  letter-spacing: .13em;
  text-transform: uppercase;
}

.live-dot {
  width: 6px;
  height: 6px;
  background: var(--acid);
  border-radius: 50%;
  box-shadow: 0 0 9px var(--acid);
}

.divider { width: 1px; height: 12px; background: var(--line); }

.intro { padding: 62px 0 43px; }

.eyebrow {
  display: flex;
  justify-content: space-between;
  margin-bottom: 25px;
  color: var(--acid);
  font-size: 10px;
  letter-spacing: .18em;
  text-transform: uppercase;
}

.intro h1 {
  max-width: 850px;
  margin: 0;
  font-family: var(--display);
  font-size: clamp(62px, 9vw, 116px);
  font-weight: 800;
  letter-spacing: -.035em;
  line-height: .77;
  text-transform: uppercase;
}

.intro h1 em { color: var(--acid); font-style: italic; }

.intro p {
  width: min(490px, 100%);
  margin: 34px 0 0 auto;
  color: #acb1a8;
  font-size: 13px;
  line-height: 1.75;
}

.calculator {
  display: grid;
  grid-template-columns: minmax(0, 1.06fr) minmax(380px, .94fr);
  border: 1px solid var(--line);
  background: var(--charcoal);
  box-shadow: 0 30px 80px rgba(0, 0, 0, .28);
}

.input-panel, .result-panel { min-width: 0; padding: 36px; }
.input-panel { border-right: 1px solid var(--line); }
.result-panel { position: relative; overflow: hidden; background: #0d100e; }
.result-panel::before {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: .055;
  background-image: linear-gradient(var(--cream) 1px, transparent 1px), linear-gradient(90deg, var(--cream) 1px, transparent 1px);
  background-size: 32px 32px;
}

.panel-heading {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 34px;
}

.panel-heading > div { display: flex; gap: 12px; align-items: center; }
.step-number { color: var(--acid); font-size: 10px; }
.panel-heading h3 { margin: 0; font-family: var(--display); font-size: 22px; letter-spacing: .08em; text-transform: uppercase; }
.scale-label { color: var(--muted); font-size: 9px; letter-spacing: .1em; text-transform: uppercase; }

.coordinate-group {
  min-width: 0;
  padding: 22px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, .018);
  transition: border-color .2s, background .2s;
}

.coordinate-group:focus-within { border-color: rgba(217, 255, 67, .5); background: var(--acid-soft); }

.group-title { display: flex; align-items: center; margin-bottom: 20px; }
.group-title > div { min-width: 0; display: grid; gap: 3px; }
.group-title strong { font-family: var(--display); font-size: 17px; letter-spacing: .06em; text-transform: uppercase; }
.group-title small { color: var(--muted); font-size: 9px; letter-spacing: .08em; text-transform: uppercase; }

.marker { width: 10px; height: 10px; margin-right: 12px; transform: rotate(45deg); }
.origin-marker { background: var(--acid); box-shadow: 0 0 10px rgba(217, 255, 67, .45); }
.target-marker { border: 2px solid var(--red); }

.text-button {
  flex-shrink: 0;
  margin-left: auto;
  padding: 5px 0;
  border: 0;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  background: none;
  cursor: pointer;
  font-size: 9px;
  letter-spacing: .09em;
  text-transform: uppercase;
}
.text-button:hover { color: var(--cream); border-color: var(--cream); }

.fields { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 12px; }
.fields label {
  min-width: 0;
  position: relative;
  display: flex;
  align-items: center;
  height: 58px;
  border-bottom: 1px solid #4a4f48;
  background: rgba(0, 0, 0, .22);
}
.fields label:focus-within { border-bottom-color: var(--acid); }
.fields label > span { position: absolute; top: 7px; left: 13px; color: var(--muted); font-size: 8px; letter-spacing: .12em; }
.fields input {
  min-width: 0;
  width: 100%;
  height: 100%;
  padding: 19px 12px 2px;
  border: 0;
  outline: 0;
  color: var(--cream);
  background: transparent;
  font-size: 21px;
  font-weight: 500;
}
.fields input::placeholder { color: #4d534c; }

.trajectory { min-width: 0; display: grid; grid-template-columns: 6px minmax(0, 1fr) 18px; gap: 7px; align-items: center; height: 34px; padding: 0 8px; overflow: hidden; }
.trajectory span:first-child { width: 5px; height: 5px; border-radius: 50%; background: var(--acid); }
.trajectory span:nth-child(2) { border-top: 1px dashed #40453f; }
.trajectory svg { display: block; width: 18px; height: 18px; max-width: 18px; fill: none; stroke: var(--muted); stroke-width: 1.3; }

.form-actions { display: grid; grid-template-columns: 1fr auto; gap: 12px; margin-top: 26px; }
.primary-button, .copy-button, .reset-button { border: 0; cursor: pointer; text-transform: uppercase; }
.primary-button {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 57px;
  padding: 0 19px;
  color: #10120d;
  background: var(--acid);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .09em;
  transition: filter .2s, transform .2s;
}
.primary-button:hover { filter: brightness(1.08); transform: translateY(-1px); }
.primary-button svg { flex: 0 0 22px; width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 1.5; }
.reset-button { padding: 0 20px; border: 1px solid var(--line); background: transparent; color: var(--muted); font-size: 9px; letter-spacing: .08em; }
.reset-button:hover { border-color: var(--cream); color: var(--cream); }
.form-message { min-height: 18px; margin: 11px 0 -18px; color: var(--red); font-size: 10px; }

.result-heading { margin-bottom: 17px; }
.status-badge { display: flex; align-items: center; gap: 7px; font-size: 8px; letter-spacing: .1em; text-transform: uppercase; }
.status-badge i { width: 6px; height: 6px; border-radius: 50%; background: currentColor; }
.status-badge.waiting { color: var(--muted); }
.status-badge.ready { color: var(--acid); }
.status-badge.warning { color: var(--red); }

.scope {
  --size: 270px;
  --bearing-inverse: 0deg;
  position: relative;
  width: var(--size);
  height: var(--size);
  margin: 4px auto 22px;
  display: grid;
  place-items: center;
  background: radial-gradient(circle, rgba(217, 255, 67, .06), transparent 67%);
}

.scope-ring { position: absolute; border-radius: 50%; }
.ring-outer {
  inset: 0;
  border: 1px solid #444940;
  background: repeating-conic-gradient(from -1deg, transparent 0 9deg, rgba(233,232,221,.27) 9deg 10deg) border-box;
  mask: radial-gradient(transparent 0 95%, #000 95.5%);
}
.ring-outer span { position: absolute; color: var(--muted); font-size: 8px; }
.ring-outer span:nth-child(1) { top: 12px; left: calc(50% - 3px); }
.ring-outer span:nth-child(2) { right: 13px; top: calc(50% - 5px); }
.ring-outer span:nth-child(3) { bottom: 11px; left: calc(50% - 3px); }
.ring-outer span:nth-child(4) { left: 12px; top: calc(50% - 5px); }
.ring-inner { inset: 35px; border: 1px dashed #343932; }
.ring-inner::before, .ring-inner::after { content: ''; position: absolute; background: #333831; }
.ring-inner::before { width: 1px; height: 100%; left: 50%; }
.ring-inner::after { height: 1px; width: 100%; top: 50%; }

.bearing-arm {
  position: absolute;
  inset: 18px;
  transform: rotate(var(--bearing));
  transition: transform .55s cubic-bezier(.2,.8,.2,1);
}
.bearing-arm::before { content: ''; position: absolute; top: 48px; left: calc(50% - 1px); width: 2px; height: 64px; background: linear-gradient(var(--cyan), transparent); }
.bearing-arm i { position: absolute; top: 41px; left: calc(50% - 4px); width: 8px; height: 8px; border-top: 2px solid var(--cyan); border-left: 2px solid var(--cyan); transform: rotate(45deg); }
.bearing-arm-label {
  position: absolute;
  top: 15px;
  left: calc(50% - 23px);
  width: 46px;
  padding: 4px 0;
  border: 1px solid rgba(87, 216, 255, .55);
  color: var(--cyan);
  background: #0d100e;
  box-shadow: 0 0 14px rgba(87, 216, 255, .12);
  font-size: 8px;
  font-weight: 600;
  letter-spacing: .06em;
  text-align: center;
  transform: rotate(var(--bearing-inverse));
  transition: transform .55s cubic-bezier(.2,.8,.2,1);
}

.scope-center {
  position: relative;
  z-index: 2;
  width: 139px;
  height: 139px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(217, 255, 67, .25);
  border-radius: 50%;
  background: #0d100e;
  box-shadow: 0 0 28px rgba(0,0,0,.7), inset 0 0 30px rgba(217,255,67,.035);
}
.range-kicker, .range-unit { color: var(--muted); font-size: 8px; letter-spacing: .14em; text-transform: uppercase; }
.scope-center strong { margin: -2px 0 -4px; color: var(--acid); font-family: var(--display); font-size: 69px; font-weight: 700; line-height: 1; letter-spacing: -.02em; font-variant-numeric: tabular-nums; }

.range-warning {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  gap: 12px;
  margin: -4px 0 16px;
  padding: 12px 14px;
  border: 1px solid rgba(255, 90, 72, .58);
  background: rgba(255, 90, 72, .09);
  color: var(--red);
}
.range-warning[hidden] { display: none; }
.warning-icon {
  flex: 0 0 25px;
  display: grid;
  place-items: center;
  width: 25px;
  height: 25px;
  border: 1px solid currentColor;
  border-radius: 50%;
  font-size: 11px;
  font-weight: 600;
}
.range-warning > div { display: grid; gap: 3px; }
.range-warning strong { font-family: var(--display); font-size: 15px; letter-spacing: .08em; text-transform: uppercase; }
.range-warning small { color: #cfa39d; font-size: 8px; line-height: 1.5; }

.solution-details { position: relative; z-index: 1; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); border: 1px solid var(--line); }
.solution-details > div { display: grid; gap: 3px; padding: 14px; }
.solution-details > div + div { border-left: 1px solid var(--line); }
.solution-details span, .solution-details small { color: var(--muted); font-size: 7px; letter-spacing: .09em; text-transform: uppercase; }
.solution-details strong { font-family: var(--display); font-size: 19px; letter-spacing: .03em; }
.solution-details .bearing-detail strong { color: var(--cyan); }
.solution-details .bearing-detail small { color: rgba(87, 216, 255, .7); }

.equation {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 12px;
  padding: 14px;
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 9px;
}
.equation-label { font-size: 7px; letter-spacing: .1em; }
.equation code { font-family: var(--mono); }
.equation strong { color: var(--cream); font-weight: 500; }

.result-actions { position: relative; z-index: 1; display: grid; grid-template-columns: 1fr auto; gap: 10px; margin-top: 16px; }
.copy-button { min-height: 44px; display: flex; justify-content: center; align-items: center; gap: 9px; background: var(--cream); color: #111410; font-size: 9px; font-weight: 600; letter-spacing: .09em; }
.copy-button svg { width: 15px; fill: none; stroke: currentColor; stroke-width: 1.3; }
.copy-button:disabled { cursor: not-allowed; opacity: .3; }
.reset-button { min-height: 44px; }

.field-note { display: flex; align-items: flex-start; gap: 15px; width: min(760px, calc(100% - 48px)); padding: 26px 0 82px; }
.note-icon { flex: 0 0 23px; display: grid; place-items: center; width: 23px; height: 23px; border: 1px solid var(--acid); border-radius: 50%; color: var(--acid); font-size: 10px; }
.field-note p { margin: 0; color: var(--muted); font-size: 10px; line-height: 1.7; }
.field-note strong { color: var(--cream); text-transform: uppercase; }

.guide {
  margin-bottom: 82px;
  border: 1px solid var(--line);
  background: rgba(16, 19, 17, .72);
}

.guide-intro {
  display: grid;
  grid-template-columns: 150px minmax(300px, 1.1fr) minmax(260px, .9fr);
  gap: 34px;
  align-items: start;
  padding: 44px 40px;
  border-bottom: 1px solid var(--line);
}

.section-label {
  color: var(--acid);
  font-size: 9px;
  letter-spacing: .13em;
  text-transform: uppercase;
}

.guide h2 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(36px, 4vw, 52px);
  line-height: .95;
  letter-spacing: -.01em;
  text-transform: uppercase;
}

.guide-intro > p {
  margin: 0;
  color: #a3aaa0;
  font-size: 11px;
  line-height: 1.8;
}

.guide-steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: 0;
  padding: 0;
  list-style: none;
  border-bottom: 1px solid var(--line);
}

.guide-steps li {
  min-height: 150px;
  display: grid;
  align-content: start;
  grid-template-columns: 30px 1fr;
  padding: 29px 30px;
}

.guide-steps li + li { border-left: 1px solid var(--line); }
.guide-steps li > span { grid-row: span 2; color: var(--acid); font-size: 9px; }
.guide-steps strong { font-family: var(--display); font-size: 18px; letter-spacing: .06em; text-transform: uppercase; }
.guide-steps p { margin: 8px 0 0; color: var(--muted); font-size: 9px; line-height: 1.7; }

.faq { display: grid; grid-template-columns: minmax(220px, .72fr) minmax(0, 1.28fr); }
.faq-heading { padding: 38px 40px; }
.faq-heading h2 { max-width: 260px; margin-top: 15px; font-size: 34px; }
.faq-list { border-left: 1px solid var(--line); }
.faq-list details + details { border-top: 1px solid var(--line); }
.faq-list summary {
  position: relative;
  padding: 23px 55px 23px 25px;
  cursor: pointer;
  font-family: var(--display);
  font-size: 16px;
  letter-spacing: .045em;
  list-style: none;
  text-transform: uppercase;
}
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary i, .faq-list summary i::after {
  position: absolute;
  width: 11px;
  height: 1px;
  background: var(--acid);
}
.faq-list summary i { top: 50%; right: 26px; }
.faq-list summary i::after { content: ''; transform: rotate(90deg); transition: transform .18s ease; }
.faq-list details[open] summary i::after { transform: rotate(0); }
.faq-list details[open] summary { color: var(--acid); }
.faq-list details p { margin: -5px 55px 23px 25px; color: var(--muted); font-size: 9px; line-height: 1.75; }

footer { padding: 28px 0 34px; border-top: 1px solid var(--line); }
.footer-credit { margin: 0; color: #c3c8be; font-size: 1rem; line-height: 1.6; }
.footer-credit strong { color: var(--cream); font-weight: 600; }
.footer-credit a {
  color: var(--acid);
  text-decoration: none;
  text-underline-offset: 4px;
}
.footer-credit a:hover { text-decoration: underline; }
.footer-credit a span { display: inline-block; margin-left: 3px; font-size: .8em; }
.footer-meta {
  display: flex;
  justify-content: space-between;
  margin-top: 23px;
  color: #656b63;
  font-size: 8px;
  letter-spacing: .1em;
  text-transform: uppercase;
}

.toast {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 30;
  padding: 13px 18px;
  color: #111410;
  background: var(--acid);
  box-shadow: 0 12px 30px rgba(0,0,0,.35);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  transform: translateY(20px);
  opacity: 0;
  pointer-events: none;
  transition: .22s ease;
}
.toast.visible { transform: translateY(0); opacity: 1; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

@media (max-width: 880px) {
  .calculator { grid-template-columns: minmax(0, 1fr); }
  .input-panel { border-right: 0; border-bottom: 1px solid var(--line); }
  .intro h1 { font-size: clamp(58px, 14vw, 92px); }
  .intro p { margin-left: 0; }
  .guide-intro { grid-template-columns: 120px 1fr; }
  .guide-intro > p { grid-column: 2; }
}

@media (max-width: 560px) {
  .site-header, main, footer { width: min(100% - 28px, 1180px); }
  .site-header { height: 76px; }
  .header-meta { display: none; }
  .intro { padding: 47px 0 34px; }
  .eyebrow span:last-child { display: none; }
  .intro h1 { font-size: clamp(48px, 14vw, 55px); line-height: .82; }
  .intro p { margin-top: 25px; font-size: 12px; }
  .input-panel, .result-panel { padding: 25px 18px; }
  .panel-heading { margin-bottom: 24px; }
  .scale-label { display: none; }
  .coordinate-group { padding: 17px 14px; }
  .fields { gap: 8px; }
  .fields input { font-size: 18px; }
  .form-actions { grid-template-columns: 1fr; }
  .scope { --size: 250px; }
  .solution-details > div { padding: 11px 8px; }
  .solution-details strong { font-size: 17px; }
  .equation { align-items: flex-start; gap: 8px; flex-direction: column; }
  .field-note { width: min(100% - 28px, 760px); padding-bottom: 55px; }
  .guide { margin-bottom: 55px; }
  .guide-intro { grid-template-columns: 1fr; gap: 18px; padding: 31px 22px; }
  .guide-intro > p { grid-column: auto; }
  .guide h2 { font-size: 38px; }
  .guide-steps { grid-template-columns: 1fr; }
  .guide-steps li { min-height: 0; padding: 24px 22px; }
  .guide-steps li + li { border-top: 1px solid var(--line); border-left: 0; }
  .faq { grid-template-columns: 1fr; }
  .faq-heading { padding: 31px 22px; }
  .faq-heading h2 { font-size: 31px; }
  .faq-list { border-top: 1px solid var(--line); border-left: 0; }
  .faq-list summary { padding-left: 22px; }
  .faq-list details p { margin-left: 22px; }
  .footer-credit { font-size: 1rem; }
  .footer-meta { gap: 12px; flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; }
}