:root {
  color-scheme: light;
  --paper: #f5f4ef;
  --surface: #fbfaf6;
  --ink: #222824;
  --muted: #687069;
  --line: #cfd3cc;
  --line-strong: #9fa79f;
  --accent: #245b49;
  --accent-soft: #e2ebe5;
  --accent-strong: #173f32;
  --plot: #5c8f9d;
  --plot-soft: #dcebed;
  --danger: #9b2f2f;
  --danger-soft: #f8e9e7;
  --symbol-font: ui-monospace, "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { color: var(--ink); background: var(--paper); overflow-x: hidden; }
button, input, textarea { font: inherit; }
a { color: inherit; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }

.tool-shell {
  display: grid;
  grid-template-columns: minmax(0, .96fr) minmax(0, 1.04fr);
  border: 1px solid var(--line-strong);
  background: var(--surface);
}

.calculator-panel,
.visual-panel { min-width: 0; padding: 24px; }
.calculator-panel { border-right: 1px solid var(--line); }
.section-heading { margin-bottom: 15px; }
h2 { margin: 0; font-size: clamp(1.2rem, 2vw, 1.48rem); line-height: 1.35; }

.values-fieldset { display: grid; gap: 15px; margin: 16px 0 0; padding: 0; border: 0; }
.values-fieldset > legend { margin-bottom: -2px; font-weight: 760; }
.input-row { min-width: 0; }
.input-row label { display: block; margin-bottom: 5px; font-weight: 720; }
.points-input,
.plain-input {
  display: block;
  width: 100%;
  min-width: 0;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  padding: 9px 10px;
  color: var(--ink);
  background: var(--surface);
}
.points-input {
  min-height: 176px;
  resize: vertical;
  font-family: var(--symbol-font);
  line-height: 1.55;
  tab-size: 4;
}
.plain-input { min-height: 44px; }
.points-input[aria-invalid="true"],
.plain-input[aria-invalid="true"] { border-color: var(--danger); background: #fff8f8; }
.unknown-row {
  margin-top: 1px;
  padding: 12px;
  border: 1px solid var(--accent);
  background: var(--accent-soft);
}
.unknown-row .plain-input { background: var(--surface); }
.optional-label { color: var(--muted); font-size: .82em; font-weight: 500; }
.field-help { margin: 4px 0 0; color: var(--muted); font-size: .78rem; overflow-wrap: anywhere; }
.field-error { min-height: 1.25em; margin: 2px 0 0; color: var(--danger); font-size: .82rem; overflow-wrap: anywhere; }
.format-note {
  margin: 15px 0 0;
  padding: 9px 11px;
  border-left: 3px solid var(--line-strong);
  color: var(--muted);
  font-size: .8rem;
  overflow-wrap: anywhere;
}
.form-error {
  margin: 12px 0 0;
  padding: 8px 10px;
  border-left: 4px solid var(--danger);
  background: var(--danger-soft);
  color: #762525;
  overflow-wrap: anywhere;
}
.form-error[hidden] { display: none; }

.form-actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 17px; }
.button {
  min-height: 42px;
  border: 1px solid var(--accent);
  border-radius: 2px;
  padding: 8px 15px;
  cursor: pointer;
  font-weight: 760;
}
.button-primary { background: var(--accent); color: #fff; }
.button-primary:hover { background: var(--accent-strong); }
.button-secondary { background: var(--surface); color: var(--accent); }
.button:hover:not(:disabled) { border-color: var(--ink); }

.result-box {
  margin-top: 20px;
  padding: 15px 16px;
  border: 1px solid var(--accent);
  border-left-width: 4px;
  background: var(--accent-soft);
}
.result-box[data-state="error"] { border-color: var(--danger); background: var(--danger-soft); }
.result-label { margin: 0; color: var(--accent); font-size: .8rem; font-weight: 780; }
.result-box[data-state="error"] .result-label { color: var(--danger); }
.result-value {
  display: block;
  margin-top: 2px;
  font-family: var(--symbol-font);
  font-size: clamp(1.2rem, 2.8vw, 1.72rem);
  line-height: 1.35;
  font-weight: 780;
  overflow-wrap: anywhere;
  word-break: break-word;
}
.result-status { margin: 6px 0 0; color: #3f4c46; font-size: .9rem; overflow-wrap: anywhere; }
.result-details {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 14px 0 0;
  border-top: 1px solid rgba(36, 91, 73, .35);
  border-left: 1px solid rgba(36, 91, 73, .35);
}
.result-details[hidden],
.result-notes[hidden] { display: none; }
.result-details > div {
  min-width: 0;
  padding: 9px 10px;
  border-right: 1px solid rgba(36, 91, 73, .35);
  border-bottom: 1px solid rgba(36, 91, 73, .35);
}
.result-details .detail-wide { grid-column: 1 / -1; }
.result-details dt { color: var(--muted); font-size: .76rem; font-weight: 760; }
.result-details dd { margin: 2px 0 0; font-size: .85rem; font-weight: 650; overflow-wrap: anywhere; word-break: break-word; }
.result-notes {
  display: grid;
  gap: 5px;
  margin: 13px 0 0;
  padding: 10px 10px 10px 28px;
  border: 1px solid rgba(36, 91, 73, .3);
  background: rgba(251, 250, 246, .58);
  color: #46524b;
  font-size: .8rem;
}
.result-notes li { overflow-wrap: anywhere; }

.visual-heading-row { display: flex; justify-content: space-between; align-items: flex-start; gap: 14px; }
.status-badge {
  flex: 0 0 auto;
  padding: 3px 8px;
  border: 1px solid var(--line-strong);
  background: var(--paper);
  color: var(--muted);
  font-size: .75rem;
  font-weight: 760;
  white-space: nowrap;
}
.status-badge[data-state="ready"] { border-color: var(--accent); background: var(--accent-soft); color: var(--accent); }
.status-badge[data-state="error"] { border-color: var(--danger); background: var(--danger-soft); color: var(--danger); }
.visual-metrics {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin: 15px 0 0;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}
.visual-metrics div { min-width: 0; padding: 9px 10px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.visual-metrics dt { color: var(--muted); font-size: .75rem; font-weight: 750; }
.visual-metrics dd { margin: 2px 0 0; font-size: .85rem; font-weight: 700; font-variant-numeric: tabular-nums; overflow-wrap: anywhere; word-break: break-word; }

.visual-stage {
  min-height: 318px;
  display: grid;
  place-items: center;
  margin-top: 15px;
  padding: 14px 10px 10px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: linear-gradient(180deg, #f2f7f8 0%, #f8f4ec 100%);
}
.plot-figure {
  position: relative;
  width: min(100%, 540px);
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line-strong);
  background: linear-gradient(180deg, #e7f0ef 0%, #f8f4ec 100%);
}
.plot-svg { display: block; width: 100%; height: auto; min-height: 265px; }
.plot-grid-line { stroke: rgba(104,112,105,.2); stroke-width: 1; stroke-dasharray: 4 7; }
.plot-axis { stroke: #758078; stroke-width: 1.5; }
.plot-regression { stroke: var(--accent); stroke-width: 3; stroke-linecap: round; }
.plot-point { fill: var(--plot); stroke: #fff; stroke-width: 3; }
.plot-unknown-guide { stroke: var(--warm, #9a5a20); stroke-width: 1.5; stroke-dasharray: 6 5; }
.plot-unknown-point { fill: #9a5a20; stroke: #fff; stroke-width: 3; }
.plot-label {
  fill: var(--accent-strong);
  font-size: 13px;
  font-weight: 750;
  paint-order: stroke;
  stroke: #f8f4ec;
  stroke-width: 5px;
  stroke-linejoin: round;
}
.plot-unknown-label { fill: #744316; }
.plot-axis-label { fill: var(--ink); font-size: 14px; font-weight: 800; }
.plot-scale-label { fill: var(--muted); font-size: 11px; }
.plot-figure[data-state="waiting"] .plot-regression,
.plot-figure[data-state="waiting"] #plot-points,
.plot-figure[data-state="waiting"] .plot-unknown-guide,
.plot-figure[data-state="waiting"] .plot-unknown-point,
.plot-figure[data-state="waiting"] .plot-unknown-label,
.plot-figure[data-state="waiting"] .plot-scale-label,
.plot-figure[data-state="error"] .plot-regression,
.plot-figure[data-state="error"] #plot-points,
.plot-figure[data-state="error"] .plot-unknown-guide,
.plot-figure[data-state="error"] .plot-unknown-point,
.plot-figure[data-state="error"] .plot-unknown-label,
.plot-figure[data-state="error"] .plot-scale-label { visibility: hidden; }
.visual-caption { margin: 7px 10px 7px; color: #3c5347; font-size: .76rem; line-height: 1.35; text-align: center; overflow-wrap: anywhere; }
.visual-description { margin: 12px 0 0; color: var(--muted); font-size: .84rem; overflow-wrap: anywhere; }
.scale-note { margin: 6px 0 0; padding-left: 11px; border-left: 3px solid var(--line-strong); color: var(--muted); font-size: .76rem; overflow-wrap: anywhere; }

.content-section { margin-top: 30px; padding-top: 25px; border-top: 1px solid var(--line-strong); }
.steps-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  margin: 0;
  padding: 0;
  border-block: 1px solid var(--line);
  list-style: none;
  counter-reset: steps;
}
.steps-list li {
  position: relative;
  min-width: 0;
  padding: 35px 12px 13px;
  border-right: 1px solid var(--line);
  background: transparent;
  counter-increment: steps;
  font-size: .88rem;
  overflow-wrap: anywhere;
}
.steps-list li:last-child { border-right: 0; }
.steps-list li::before {
  content: counter(steps, decimal-leading-zero);
  position: absolute;
  top: 7px;
  left: 12px;
  color: var(--accent);
  font-size: .75rem;
  font-weight: 800;
}
.formula-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}
.formula-list article {
  min-width: 0;
  display: grid;
  gap: 4px;
  padding: 13px 14px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.formula-list strong { font-family: var(--symbol-font); overflow-wrap: anywhere; }
.formula-list span { color: var(--muted); font-size: .82rem; overflow-wrap: anywhere; }
.example-box { margin-top: 14px; padding: 14px 16px; border: 1px solid var(--accent); background: var(--accent-soft); }
.example-box h3 { margin: 0; color: var(--accent); font-size: .95rem; }
.example-box p { margin: 7px 0 0; color: #38413b; font-size: .88rem; overflow-wrap: anywhere; }
.scope-box { border: 1px solid var(--line); }
.scope-box ul {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 0;
  padding: 0;
  list-style: none;
}
.scope-box li {
  min-width: 0;
  padding: 10px 13px 10px 30px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: .84rem;
  overflow-wrap: anywhere;
}
.scope-box li:nth-child(2n) { border-right: 0; }
.scope-box li:nth-last-child(-n + 2) { border-bottom: 0; }
.scope-box li::before { content: "—"; margin-left: -17px; margin-right: 7px; color: var(--accent); }

@media (max-width: 900px) {
  .tool-shell { grid-template-columns: 1fr; }
  .calculator-panel { border-right: 0; border-bottom: 1px solid var(--line); }
  .steps-list { grid-template-columns: repeat(3, 1fr); }
  .scope-box ul { grid-template-columns: 1fr; }
  .scope-box li,
  .scope-box li:nth-child(2n),
  .scope-box li:nth-last-child(-n + 2) { border-right: 0; border-bottom: 1px solid var(--line); }
  .scope-box li:last-child { border-bottom: 0; }
}

@media (max-width: 760px) {
  .calculator-panel,
  .visual-panel { padding: 18px; }
  .formula-list { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  .calculator-panel,
  .visual-panel { padding: 17px 14px; }
  .form-actions { display: grid; grid-template-columns: 1fr; }
  .button { width: 100%; }
  .visual-metrics { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .result-details { grid-template-columns: 1fr; }
  .result-details .detail-wide { grid-column: auto; }
  .steps-list { grid-template-columns: 1fr; }
  .steps-list li,
  .steps-list li:nth-child(2) { border-right: 0; border-bottom: 1px solid var(--line); }
  .steps-list li:last-child { border-bottom: 0; }
}

@media (max-width: 430px) {
  .points-input { min-height: 160px; }
  .plot-figure { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; }
}