:root {
  --paper: #eee9df;
  --ink: #151515;
  --muted: #6b6258;
  --red: #df3c2f;
  --acid: #e8ff3d;
  --line: rgba(22, 22, 22, 0.2);
  --mono: "DM Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --sans: Manrope, Inter, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

html {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
}

body {
  min-height: 100vh;
  margin: 0;
  background:
    radial-gradient(circle at 82% 10%, #fff 0, transparent 25rem),
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: auto, 40px 40px, 40px 40px;
}

button, input { font: inherit; }
.site-shell { width: min(1500px, 100%); margin: 0 auto; padding: 26px clamp(20px, 5vw, 72px) 38px; }

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-bottom: clamp(48px, 8vw, 110px);
}

.back-link {
  color: var(--ink);
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-decoration: none;
  text-transform: uppercase;
}

.brand {
  margin: 0;
  font-size: 30px;
  font-weight: 800;
  letter-spacing: -0.08em;
}

.brand span { color: var(--red); }
.kicker, .step {
  margin: 0;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.65fr) minmax(260px, 0.7fr);
  gap: clamp(32px, 6vw, 100px);
  align-items: end;
  padding-bottom: clamp(52px, 8vw, 96px);
}

.title {
  max-width: 1050px;
  margin: 20px 0 0;
  font-size: clamp(58px, 9.7vw, 146px);
  line-height: 0.81;
  letter-spacing: -0.075em;
}

.title span { color: var(--red); }
.hero-copy {
  max-width: 560px;
  margin: 0;
  font-size: clamp(17px, 1.7vw, 23px);
  line-height: 1.5;
}

.workspace {
  display: grid;
  grid-template-columns: minmax(310px, 0.82fr) minmax(0, 1.9fr);
  border-top: 2px solid var(--ink);
  border-bottom: 2px solid var(--ink);
}

.input-panel { padding: clamp(30px, 4vw, 58px) clamp(22px, 3.5vw, 52px) 38px 0; border-right: 1px solid var(--ink); }
.result-panel { min-width: 0; padding: clamp(30px, 4vw, 58px) 0 38px clamp(22px, 3.5vw, 52px); }
.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 30px;
}

.section-head h2 {
  margin: 0;
  font-size: clamp(28px, 3vw, 46px);
  letter-spacing: -0.045em;
}

.step {
  font-size: 10px;
  letter-spacing: 0.12em;
}

.input-grid {
  display: grid;
  gap: 14px;
}

.field {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 7px 14px;
  padding: 16px 0 13px;
  border-bottom: 1px solid var(--line);
}

.field label {
  display: block;
  font-size: 14px;
  font-weight: 700;
}

.unit {
  align-self: end;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.field input {
  grid-column: 1 / -1;
  width: 100%;
  min-width: 0;
  padding: 5px 0 3px;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: var(--ink);
  font-size: clamp(28px, 3vw, 42px);
  font-weight: 800;
  letter-spacing: -0.04em;
  outline: 0;
}

.field:focus-within { border-color: var(--red); }
.field:focus-within label { color: var(--red); }
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 11px;
  padding-top: 26px;
}

.action {
  min-height: 44px;
  border: 2px solid var(--ink);
  background: var(--acid);
  color: var(--ink);
  box-shadow: 4px 4px 0 var(--ink);
  padding: 11px 15px;
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
}

.action.secondary { background: transparent; box-shadow: none; }
.microcopy {
  margin: 28px 0 0;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 9px;
  line-height: 1.65;
  letter-spacing: 0.03em;
}

.results {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--ink);
  border-left: 1px solid var(--ink);
  gap: 0;
}

.result-card {
  min-width: 0;
  min-height: 255px;
  display: flex;
  flex-direction: column;
  border-right: 1px solid var(--paper);
  border-bottom: 1px solid var(--paper);
  background: #151515;
  color: var(--paper);
  padding: clamp(20px, 2.4vw, 34px);
}

.result-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
}

.result-card h3 {
  margin: 0;
  font-size: clamp(22px, 2.4vw, 34px);
  letter-spacing: -0.04em;
}

.score-badge {
  border: 1px solid rgba(238, 233, 223, 0.5);
  flex: 0 0 auto;
  padding: 5px 7px;
  color: var(--acid);
  font-family: var(--mono);
  font-size: 8px;
  letter-spacing: 0.08em;
}

.result-value {
  display: block;
  margin: auto 0 18px;
  padding-top: 18px;
  color: rgba(238, 233, 223, 0.4);
  font-size: clamp(54px, 6vw, 86px);
  font-weight: 800;
  line-height: 0.8;
  letter-spacing: -0.065em;
  font-variant-numeric: tabular-nums;
}

.result-value.ready { color: var(--acid); }
.formula, .result-inputs {
  margin: 0;
  color: rgba(238, 233, 223, 0.72);
  font-family: var(--mono);
  font-size: 9px;
  line-height: 1.4;
}

.formula { min-height: 2.8em; }
.result-inputs { margin-top: 8px; color: rgba(238, 233, 223, 0.5); font-size: 8px; letter-spacing: 0.03em; }
.score-guide {
  margin-top: clamp(58px, 8vw, 110px);
  padding: clamp(30px, 5vw, 70px);
  background: var(--ink);
  color: var(--paper);
}

.guide-grid {
  display: grid;
  grid-template-columns: 0.7fr 1fr 1fr;
  gap: clamp(28px, 5vw, 76px);
}

.guide-block {
  border-top: 1px solid rgba(238, 233, 223, 0.42);
  padding-top: 18px;
}

.guide-title {
  margin: 18px 0 0;
  font-size: clamp(36px, 5vw, 72px);
  line-height: 0.95;
  letter-spacing: -0.055em;
}

.guide-block h3 {
  margin: 0 0 12px;
  color: var(--acid);
  font-size: 16px;
}

.guide-block p, .formula-item p {
  margin: 0;
  color: rgba(238, 233, 223, 0.76);
  line-height: 1.62;
}

.formula-guide {
  margin-top: clamp(34px, 6vw, 72px);
  padding-top: clamp(34px, 5vw, 62px);
  border-top: 1px solid rgba(238, 233, 223, 0.28);
}

.formula-guide-head {
  display: grid;
  grid-template-columns: 0.7fr 2fr;
  gap: clamp(28px, 5vw, 76px);
  align-items: end;
  margin-bottom: clamp(26px, 4vw, 46px);
}

.formula-guide-head h2 {
  margin: 0;
  font-size: clamp(30px, 4.2vw, 60px);
  line-height: 0.98;
  letter-spacing: -0.05em;
}

.formula-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid rgba(238, 233, 223, 0.35);
  border-left: 1px solid rgba(238, 233, 223, 0.35);
  gap: 0;
}

.formula-item {
  min-width: 0;
  min-height: 190px;
  border-right: 1px solid rgba(238, 233, 223, 0.35);
  border-bottom: 1px solid rgba(238, 233, 223, 0.35);
  padding: clamp(20px, 2.5vw, 32px);
}

.formula-item span {
  display: block;
  margin-bottom: 20px;
  color: rgba(238, 233, 223, 0.45);
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.12em;
}

.formula-item h3 {
  margin: 24px 0 14px;
  color: var(--acid);
  font-size: clamp(19px, 2vw, 27px);
  letter-spacing: -0.035em;
}

.formula-item p {
  font-family: var(--mono);
  font-size: clamp(11px, 1.1vw, 14px);
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding: 24px 0 10px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

@media (max-width: 980px) {
  .hero, .workspace, .guide-grid, .formula-guide-head { grid-template-columns: 1fr; }
  .input-panel { padding-right: 0; padding-bottom: 48px; border-right: 0; border-bottom: 1px solid var(--ink); }
  .result-panel { padding-left: 0; }
  .guide-grid { grid-template-columns: 1fr 1fr; }
  .guide-intro { grid-column: 1 / -1; }
  .formula-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 650px) {
  .site-shell { padding-inline: 18px; }
  .results, .guide-grid, .formula-guide-head, .formula-list { grid-template-columns: 1fr; }
  .section-head, .footer { align-items: flex-start; flex-direction: column; }
  .title { font-size: clamp(55px, 19vw, 92px); }
  .topbar { align-items: flex-start; }
  .topbar .kicker { max-width: 165px; text-align: right; line-height: 1.5; }
  .result-card { min-height: 235px; }
}