:root {
  --ink: #18221c;
  --muted: #657169;
  --paper: #f4f1e8;
  --card: #fbfaf5;
  --line: #d9d8ce;
  --green: #17734d;
  --green-dark: #0f5137;
  --mint: #dbe9df;
  --mono: "DM Mono", monospace;
  --sans: "Noto Sans JP", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
}
.grain {
  position: fixed; inset: 0; pointer-events: none; z-index: 10; opacity: .18;
  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='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.12'/%3E%3C/svg%3E");
}
.site-header {
  max-width: 1240px; margin: 0 auto; padding: 26px 28px;
  display: flex; justify-content: space-between; align-items: center;
  border-bottom: 1px solid rgba(24,34,28,.14);
}
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font-weight: 700; letter-spacing: -.04em; font-size: 20px; }
.brand-mark { width: 29px; height: 29px; display: inline-flex; color: var(--green); }
.brand-mark svg { width: 100%; fill: currentColor; }
.header-note { font: 500 11px var(--mono); letter-spacing: .12em; text-transform: uppercase; color: var(--muted); }
main { overflow: hidden; }
.hero { max-width: 1240px; margin: 0 auto; padding: 36px 28px 14px; }
.eyebrow { display: flex; align-items: center; gap: 10px; font: 500 11px var(--mono); letter-spacing: .16em; color: var(--green); }
.eyebrow span { width: 28px; height: 1px; background: var(--green); }
.hero h1 { max-width: none; margin: 18px 0 18px; font-size: clamp(28px, 4.2vw, 54px); line-height: 1.2; letter-spacing: -.055em; font-weight: 600; white-space: nowrap; }
.hero h1 em { font-style: normal; color: var(--green); }
.hero p { margin: 0 0 0 min(18vw, 220px); color: var(--muted); line-height: 2; font-size: 15px; }
.converter-shell {
  max-width: 1320px; margin: 0 auto 110px; padding: 0 16px;
  display: grid; grid-template-columns: minmax(0, .92fr) 42px minmax(0, 1.08fr); align-items: stretch;
}
.input-card, .results-card { background: var(--card); border: 1px solid var(--line); padding: 28px; min-width: 0; }
.input-card { border-radius: 4px 0 0 4px; }
.results-card { border-radius: 0 4px 4px 0; }
.card-heading { display: flex; justify-content: space-between; align-items: center; margin-bottom: 34px; }
.card-heading > div { display: flex; align-items: baseline; gap: 14px; }
.step { font: 500 11px var(--mono); color: var(--green); }
.card-heading h2 { font-size: 19px; letter-spacing: -.03em; margin: 0; }
.text-button { border: 0; background: none; color: var(--muted); font: 12px var(--sans); cursor: pointer; padding: 8px; }
.text-button:hover { color: var(--green); }
.input-wrap {
  display: block;
  position: relative;
  padding: 13px 16px 5px;
  border: 1px solid #b8bdb7;
  border-radius: 4px;
  background: #fff;
  cursor: text;
  transition: border-color .2s ease, box-shadow .2s ease, background .2s ease;
}
.input-wrap:focus-within {
  border-color: var(--green);
  background: #fff;
  box-shadow: 0 0 0 3px rgba(23,115,77,.12);
}
.field-label {
  display: block;
  margin-bottom: 2px;
  color: var(--green);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .08em;
}
textarea {
  display: block; width: 100%; resize: none; border: 0;
  outline: 0; background: transparent; color: var(--ink); padding: 7px 0 10px;
  min-height: 76px;
  font: 500 clamp(15px, 1.5vw, 18px)/1.55 var(--mono);
}
textarea::placeholder { color: #aaa99f; }
.input-meta { display: flex; justify-content: space-between; gap: 12px; margin-top: 10px; color: var(--muted); font-size: 10px; }
.detected { color: var(--green); font-family: var(--mono); font-weight: 500; }
.examples { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; margin-top: 40px; }
.examples > span { flex-basis: 100%; margin: 0 0 2px; font-size: 11px; color: var(--muted); }
.examples button { border: 1px solid var(--line); border-radius: 30px; background: transparent; padding: 8px 13px; color: var(--ink); font: 11px var(--sans); cursor: pointer; transition: .2s; }
.examples button:hover { border-color: var(--green); background: var(--mint); color: var(--green-dark); }
.examples button b { margin-left: 5px; color: var(--green); font: 500 9px var(--mono); letter-spacing: .04em; }
.error { color: #a73c32; font-size: 12px; min-height: 1.5em; margin: 22px 0 0; }
.direction { display: flex; align-items: center; gap: 7px; color: var(--green); }
.direction span { flex: 1; height: 1px; background: var(--green); }
.direction svg { width: 18px; fill: none; stroke: currentColor; stroke-width: 1.5; }
.live-dot { font: 500 10px var(--mono); letter-spacing: .08em; color: var(--green); }
.live-dot i { display: inline-block; width: 6px; height: 6px; border-radius: 50%; background: #2da572; margin-right: 5px; box-shadow: 0 0 0 4px rgba(45,165,114,.12); }
.result-list { border-top: 1px solid var(--line); }
.result-row { min-height: 85px; display: grid; grid-template-columns: 66px minmax(0, 1fr) auto; gap: 10px; align-items: center; border-bottom: 1px solid var(--line); }
.format-label strong { display: block; font: 500 12px var(--mono); color: var(--green); }
.format-label span { font-size: 10px; color: var(--muted); }
.result-row output { font: 500 clamp(12px, 1.15vw, 15px)/1.5 var(--mono); letter-spacing: -.035em; white-space: nowrap; }
.copy-button { display: flex; align-items: center; gap: 5px; padding: 8px; border: 0; background: none; color: var(--muted); font: 10px var(--sans); cursor: pointer; }
.copy-button:hover { color: var(--green); }
.copy-button svg { width: 16px; fill: none; stroke: currentColor; stroke-width: 1.5; }
.map-link { display: flex; align-items: center; margin-top: 25px; padding: 15px 18px; background: var(--green); color: white; text-decoration: none; font-size: 12px; font-weight: 600; transition: .2s; }
.map-link:hover { background: var(--green-dark); }
.map-link.disabled { pointer-events: none; opacity: .38; }
.map-link svg { width: 17px; fill: none; stroke: currentColor; stroke-width: 1.5; margin-right: 9px; }
.map-link .arrow { margin: 0 0 0 auto; }
.format-guide { max-width: 1240px; margin: 0 auto 120px; padding: 0 28px; display: grid; grid-template-columns: 1fr 2fr; gap: 90px; }
.section-number { color: var(--green); font: 500 10px var(--mono); letter-spacing: .12em; }
.guide-intro h2 { font-size: clamp(34px, 4vw, 53px); line-height: 1.3; letter-spacing: -.055em; margin: 18px 0; }
.guide-intro p { max-width: 290px; color: var(--muted); font-size: 13px; line-height: 1.9; }
.guide-grid { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); }
.guide-grid article { padding: 24px 24px 10px; border-left: 1px solid var(--line); }
.guide-grid article > span { color: var(--muted); font: 10px var(--mono); }
.guide-grid h3 { font-size: 16px; margin: 40px 0 16px; }
.guide-grid h3 small { display: block; color: var(--green); font: 10px var(--mono); margin-top: 4px; }
.guide-grid code { display: block; font: 500 14px var(--mono); white-space: nowrap; margin-bottom: 35px; }
.guide-grid p { color: var(--muted); font-size: 11px; line-height: 1.9; }
footer { max-width: 1240px; margin: 0 auto; padding: 36px 28px; border-top: 1px solid var(--line); display: flex; align-items: center; justify-content: space-between; }
.footer-brand { font-size: 15px; }
.footer-brand .brand-mark { width: 23px; height: 23px; }
footer p, footer > span { color: var(--muted); font-size: 10px; }
.toast { position: fixed; left: 50%; bottom: 30px; transform: translate(-50%, 20px); background: var(--ink); color: white; padding: 11px 18px; font-size: 11px; border-radius: 2px; opacity: 0; pointer-events: none; transition: .25s; z-index: 20; }
.toast.show { opacity: 1; transform: translate(-50%, 0); }

@media (max-width: 1100px) {
  .copy-button span { display: none; }
}
@media (max-width: 850px) {
  .hero { padding-top: 32px; }
  .hero p { margin-left: 0; }
  .converter-shell { grid-template-columns: 1fr; }
  .input-card, .results-card { border-radius: 4px; }
  .direction { height: 58px; flex-direction: column; justify-content: center; }
  .direction span { width: 1px; flex: 1; }
  .direction svg { transform: rotate(90deg); flex: 0 0 18px; }
  .result-row output { white-space: normal; overflow-wrap: anywhere; }
  .format-guide { grid-template-columns: 1fr; gap: 45px; }
}
@media (max-width: 590px) {
  .site-header { padding: 20px; }
  .header-note { display: none; }
  .hero { padding: 26px 20px 12px; }
  .hero h1 { font-size: clamp(19px, 6.2vw, 28px); }
  .desktop-only { display: none; }
  .converter-shell { padding: 0 14px; margin-bottom: 80px; }
  .input-card, .results-card { padding: 25px 20px; }
  .result-row { grid-template-columns: 58px minmax(0, 1fr) auto; gap: 7px; }
  .copy-button span { display: none; }
  .format-guide { padding: 0 20px; margin-bottom: 80px; }
  .guide-grid { grid-template-columns: 1fr; }
  .guide-grid article { border-bottom: 1px solid var(--line); padding: 24px 18px; }
  .guide-grid h3 { margin-top: 20px; }
  .guide-grid code { margin-bottom: 20px; }
  footer { margin: 0 20px; padding: 26px 0; }
  footer p { display: none; }
}