:root {
  --ink: #102736;
  --muted: #5e7280;
  --line: rgba(16, 39, 54, .13);
  --paper: #f6fafb;
  --surface: rgba(255, 255, 255, .82);
  --blue: #0876a5;
  --blue-dark: #065371;
  --cyan: #22aac7;
  --amber: #f5ad45;
  --green: #2b9d77;
  --radius: 28px;
  color-scheme: light;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 8% 10%, rgba(34, 170, 199, .13), transparent 29rem),
    radial-gradient(circle at 94% 26%, rgba(245, 173, 69, .12), transparent 27rem),
    var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", sans-serif;
  line-height: 1.7;
}

a { color: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button:focus-visible, a:focus-visible, summary:focus-visible { outline: 3px solid rgba(8, 118, 165, .35); outline-offset: 4px; }
[hidden] { display: none !important; }

.site-header {
  width: min(1180px, calc(100% - 40px));
  min-height: 84px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border-bottom: 1px solid var(--line);
}

.brand { display: inline-flex; align-items: center; gap: 12px; color: var(--ink); font-weight: 760; text-decoration: none; letter-spacing: -.02em; }
.brand img { border-radius: 11px; box-shadow: 0 8px 22px rgba(6, 83, 113, .18); }
.language-switch { display: flex; gap: 4px; padding: 4px; background: rgba(255,255,255,.65); border: 1px solid var(--line); border-radius: 999px; }
.language-switch button { border: 0; border-radius: 999px; padding: 8px 14px; color: var(--muted); background: transparent; font: inherit; font-size: .82rem; font-weight: 700; cursor: pointer; }
.language-switch button.active { color: white; background: var(--blue); box-shadow: 0 4px 12px rgba(8,118,165,.22); }

main { overflow: hidden; }
.language-page, footer { width: min(1180px, calc(100% - 40px)); margin: 0 auto; }
.hero { min-height: 670px; display: grid; grid-template-columns: 1.08fr .92fr; align-items: center; gap: clamp(40px, 7vw, 100px); padding: 92px 0 104px; }
.eyebrow { margin: 0 0 14px; color: var(--blue); font-size: .75rem; font-weight: 820; letter-spacing: .16em; }
h1, h2, h3, p { margin-top: 0; }
h1 { margin-bottom: 24px; font-size: clamp(3.2rem, 6.2vw, 6.6rem); line-height: .98; letter-spacing: -.065em; }
h1 span { color: var(--blue); }
.lead { max-width: 700px; margin-bottom: 32px; color: var(--muted); font-size: clamp(1rem, 1.6vw, 1.2rem); }
.hero-actions, .support-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 14px; }
.primary-button, .secondary-button { display: inline-flex; align-items: center; justify-content: center; min-height: 48px; padding: 11px 20px; border-radius: 999px; font-weight: 760; text-decoration: none; }
.primary-button { color: white; background: var(--blue); box-shadow: 0 10px 24px rgba(8,118,165,.22); }
.primary-button:hover { background: var(--blue-dark); transform: translateY(-1px); }
.secondary-button { border: 1px solid var(--line); background: rgba(255,255,255,.7); }
.text-link { color: var(--blue-dark); font-weight: 750; text-underline-offset: 5px; }

.instrument-wrap { position: relative; min-height: 690px; display: grid; place-items: center; }
.instrument-wrap::before { content: ""; position: absolute; width: 520px; height: 520px; border-radius: 50%; background: linear-gradient(145deg, rgba(34,170,199,.22), rgba(245,173,69,.19)); filter: blur(2px); }
.app-screenshot-frame { position: relative; z-index: 1; width: min(100%, 340px); margin: 0; padding: 9px; border: 1px solid rgba(255,255,255,.92); border-radius: 40px; background: #172a34; box-shadow: 0 36px 90px rgba(20,68,88,.24); transform: rotate(1.5deg); }
.app-screenshot { display: block; width: 100%; height: auto; border-radius: 31px; background: white; }
.app-screenshot-frame figcaption { position: absolute; right: 20px; bottom: 22px; padding: 5px 9px; border-radius: 999px; color: rgba(255,255,255,.9); background: rgba(16,39,54,.72); backdrop-filter: blur(8px); font-size: .65rem; font-weight: 700; letter-spacing: .04em; }

.content-section { padding: 96px 0; border-top: 1px solid var(--line); }
.intro-section { display: grid; grid-template-columns: 80px 1fr; gap: 34px; }
.section-number { color: var(--cyan); font-size: .78rem; font-weight: 850; letter-spacing: .15em; }
.section-heading { display: flex; align-items: baseline; gap: 24px; margin-bottom: 38px; }
h2 { margin-bottom: 16px; font-size: clamp(2rem, 4vw, 3.7rem); line-height: 1.1; letter-spacing: -.045em; }
.section-heading h2 { margin: 0; }
.section-lead { max-width: 860px; color: var(--muted); font-size: clamp(1.1rem, 2vw, 1.45rem); }

.step-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.step-card, .mode-grid article { padding: 26px; border: 1px solid var(--line); border-radius: 22px; background: var(--surface); }
.step-card > span { display: grid; width: 34px; height: 34px; margin-bottom: 48px; place-items: center; border-radius: 50%; color: white; background: var(--blue); font-size: .8rem; font-weight: 800; }
.step-card h3, .mode-grid h3 { margin-bottom: 8px; font-size: 1.15rem; }
.step-card p, .mode-grid p { margin: 0; color: var(--muted); font-size: .92rem; }

.values-section { position: relative; }
.value-grid { display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid var(--line); border-left: 1px solid var(--line); }
.value-grid article { min-height: 160px; padding: 24px; display: flex; flex-direction: column; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); background: rgba(255,255,255,.45); }
.value-grid strong { color: var(--blue); font-size: 1.65rem; letter-spacing: -.03em; }
.value-grid span { margin-top: auto; font-weight: 750; }
.value-grid small { color: var(--muted); }
.unit-note { margin: 22px 0 0; color: var(--muted); font-size: .85rem; }

.mode-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.mode-grid article { min-height: 260px; display: flex; flex-direction: column; }
.mode-grid h3 { margin-top: auto; font-size: 1.65rem; }
.mode-tag { align-self: flex-start; padding: 5px 9px; color: var(--blue-dark); background: rgba(34,170,199,.12); border-radius: 7px; font-size: .65rem; font-weight: 850; letter-spacing: .12em; }

.faq-list { border-top: 1px solid var(--line); }
details { border-bottom: 1px solid var(--line); }
summary { padding: 23px 4px; display: flex; align-items: center; justify-content: space-between; gap: 20px; cursor: pointer; list-style: none; font-weight: 760; }
summary::-webkit-details-marker { display: none; }
details p { max-width: 850px; margin: -8px 0 24px; color: var(--muted); }
details[open] summary span { transform: rotate(45deg); }

.support-card { margin-top: 96px; margin-bottom: 96px; padding: clamp(34px, 6vw, 72px); display: grid; grid-template-columns: 1.2fr .8fr; gap: 56px; border: 0; border-radius: var(--radius); color: white; background: linear-gradient(135deg, var(--blue-dark), #0b7790 62%, #149b9e); box-shadow: 0 28px 70px rgba(6,83,113,.18); }
.support-card .eyebrow, .support-card small { color: rgba(255,255,255,.68); }
.support-card h2 { margin-bottom: 14px; }
.support-card p { color: rgba(255,255,255,.82); }
.support-actions { flex-direction: column; align-items: stretch; justify-content: center; }
.support-actions .primary-button { color: var(--blue-dark); background: white; box-shadow: none; }
.support-actions .secondary-button { color: white; border-color: rgba(255,255,255,.25); background: rgba(255,255,255,.08); }

footer { min-height: 110px; display: flex; align-items: center; justify-content: space-between; gap: 20px; border-top: 1px solid var(--line); color: var(--muted); font-size: .8rem; }
.footer-brand { font-size: .9rem; }

@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; padding-top: 68px; }
  .instrument-wrap { min-height: 650px; }
  .step-grid { grid-template-columns: 1fr 1fr; }
  .mode-grid { grid-template-columns: 1fr; }
  .mode-grid article { min-height: 190px; }
  .support-card { grid-template-columns: 1fr; }
}

@media (max-width: 620px) {
  .site-header, .language-page, footer { width: min(100% - 28px, 1180px); }
  .site-header { min-height: 76px; }
  .brand span { font-size: .9rem; }
  .language-switch button { padding: 7px 10px; }
  .hero { min-height: auto; gap: 28px; padding: 64px 0 72px; }
  h1 { font-size: clamp(2.7rem, 14vw, 4rem); }
  .instrument-wrap { min-height: 570px; }
  .instrument-wrap::before { width: 350px; height: 350px; }
  .app-screenshot-frame { width: min(100%, 280px); padding: 7px; border-radius: 34px; transform: none; }
  .app-screenshot { border-radius: 27px; }
  .content-section { padding: 70px 0; }
  .intro-section { grid-template-columns: 1fr; gap: 16px; }
  .section-heading { gap: 14px; }
  .step-grid, .value-grid { grid-template-columns: 1fr; }
  .step-card > span { margin-bottom: 26px; }
  .value-grid { border-right: 1px solid var(--line); }
  .value-grid article { min-height: 130px; border-right: 0; }
  .support-card { margin-top: 60px; margin-bottom: 60px; padding: 32px 24px; border-radius: 22px; }
  footer { padding: 24px 0; flex-direction: column; justify-content: center; }
}