: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;
  --warm: #9a5a20;
  --warm-soft: #f6eadf;
  --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; }
button, input, select { font: inherit; }
a { color: inherit; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }

.tool-shell {
  display: grid;
  grid-template-columns: minmax(0, .98fr) minmax(0, 1.02fr);
  border: 1px solid var(--line-strong);
  background: var(--surface);
}

.calculator-panel,
.explanation-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; }
h3 { margin: 0; font-size: 1rem; line-height: 1.4; }

.input-row { min-width: 0; }
.input-row + .input-row { margin-top: 15px; }
.input-row label { display: block; margin-bottom: 5px; font-weight: 720; }
.input-row input,
.input-row select {
  width: 100%;
  min-width: 0;
  min-height: 44px;
  border: 1px solid var(--line-strong);
  border-radius: 2px;
  padding: 9px 10px;
  color: var(--ink);
  background: var(--surface);
}
.input-row input:focus,
.input-row select:focus { border-color: var(--accent); }
.input-row input[aria-invalid="true"],
.input-row select[aria-invalid="true"] { border-color: var(--danger); background: #fff8f8; }
.prefix-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 15px;
}
.prefix-grid .input-row + .input-row { margin-top: 0; }
.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; }
.input-note {
  margin: 16px 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],
.result-note[hidden],
.comparison-note[hidden],
.result-details[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); }
.form-status { min-height: 1.3em; margin: 10px 0 0; color: var(--muted); font-size: .84rem; overflow-wrap: anywhere; }

.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-values {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 6px;
}
.result-value-block { min-width: 0; }
.result-term { display: block; color: var(--muted); font-size: .76rem; font-weight: 740; }
.result-value {
  display: block;
  margin-top: 1px;
  font-size: clamp(1.18rem, 2.7vw, 1.65rem);
  line-height: 1.3;
  font-weight: 780;
  font-variant-numeric: tabular-nums;
  overflow-wrap: anywhere;
  word-break: break-word;
}
.result-scientific { font-family: var(--symbol-font); font-size: clamp(1rem, 2.2vw, 1.32rem); }
.result-status { margin: 7px 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 > 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 dt { color: var(--muted); font-size: .76rem; font-weight: 760; }
.result-details dd { margin: 2px 0 0; font-size: .84rem; font-weight: 620; overflow-wrap: anywhere; word-break: break-word; }
.result-note,
.comparison-note {
  margin: 10px 0 0;
  padding: 8px 10px;
  color: #39453e;
  background: rgba(255, 255, 255, .5);
  overflow-wrap: anywhere;
}
.comparison-note { border-left: 3px solid var(--warm); background: var(--warm-soft); color: #744316; }

.explanation-heading { 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); }
.prefix-summary {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 16px;
}
.prefix-card {
  min-width: 0;
  padding: 13px;
  border: 1px solid var(--line);
  background: #fff;
}
.prefix-card h3 { color: var(--muted); font-size: .76rem; }
.prefix-card-name { margin: 8px 0 0; font-weight: 720; overflow-wrap: anywhere; }
.prefix-card-symbol {
  margin: 2px 0 0;
  color: var(--accent);
  font-family: var(--symbol-font);
  font-size: 1.5rem;
  font-weight: 760;
}
.prefix-card-factor { margin: 4px 0 0; color: var(--muted); font-size: .84rem; overflow-wrap: anywhere; }
.visual-description { margin: 16px 0 0; color: #38413b; font-size: .9rem; overflow-wrap: anywhere; }
.normalization-note {
  margin: 10px 0 0;
  padding-left: 11px;
  border-left: 3px solid var(--line-strong);
  color: var(--muted);
  font-size: .78rem;
  overflow-wrap: anywhere;
}

.content-section { margin-top: 30px; padding-top: 25px; border-top: 1px solid var(--line-strong); }
.steps-list { display: grid; gap: 8px; margin: 0; padding-left: 1.4rem; }
.steps-list li { padding-left: 4px; overflow-wrap: anywhere; }
.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 > div {
  min-width: 0;
  display: grid;
  gap: 3px;
  padding: 12px 13px;
  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); overflow-wrap: anywhere; }
.scope-note {
  margin-top: 14px;
  padding: 13px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.scope-note ul { display: grid; gap: 7px; margin: 8px 0 0; padding-left: 1.2rem; }
.scope-note li { color: var(--muted); font-size: .86rem; overflow-wrap: anywhere; }
.table-wrap { max-width: 100%; overflow-x: auto; border: 1px solid var(--line); }
#prefix-table { width: 100%; border-collapse: collapse; font-size: .86rem; }
#prefix-table th,
#prefix-table td { padding: 8px 10px; border-bottom: 1px solid var(--line); text-align: left; white-space: nowrap; }
#prefix-table th { color: var(--muted); font-size: .76rem; font-weight: 760; }
#prefix-table tbody tr:last-child th,
#prefix-table tbody tr:last-child td { border-bottom: 0; }
#prefix-table tbody th { color: var(--ink); font-weight: 650; }
#prefix-table .prefix-symbol { color: var(--accent); font-family: var(--symbol-font); font-weight: 760; }
#prefix-table tr[data-selected="true"] { background: var(--accent-soft); }
.source-note { margin: 11px 0 0; color: var(--muted); font-size: .8rem; overflow-wrap: anywhere; }
.source-note a { color: var(--accent); text-underline-offset: 3px; }

@media (max-width: 900px) {
  .tool-shell { grid-template-columns: 1fr; }
  .calculator-panel { border-right: 0; border-bottom: 1px solid var(--line); }
}

@media (max-width: 700px) {
  .formula-list { grid-template-columns: 1fr; }
  .formula-list > div { border-right: 0; }
  .explanation-heading { gap: 8px; }
  .status-badge { font-size: .7rem; }
}

@media (max-width: 600px) {
  .calculator-panel,
  .explanation-panel { padding: 17px 14px; }
  .prefix-grid,
  .result-values,
  .result-details,
  .prefix-summary { grid-template-columns: 1fr; }
  .form-actions { display: grid; grid-template-columns: 1fr; }
  .button { width: 100%; }
  .footer-links { gap: 10px; }
}

@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; }
}