@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@400;500&display=swap');

:root {
  color-scheme: dark;
  --font-body: "Inter", "Noto Sans JP", system-ui, sans-serif;
  --font-heading: "Inter", "Noto Sans JP", system-ui, sans-serif;
  --edge: clamp(20px, 6vw, 56px);
  --ink-dim: var(--color-neutral-400);
  --ink-faint: var(--color-neutral-500);
  --accent-ink: var(--color-accent-300);
  --glow: color-mix(in srgb, var(--color-accent-900) 80%, transparent);
  --fall: color-mix(in srgb, black 30%, transparent);
}
@media (prefers-color-scheme: light) {
  :root {
    color-scheme: light;
    --color-bg: var(--color-neutral-100);
    --color-surface: var(--color-neutral-200);
    --color-text: var(--color-neutral-900);
    --color-accent: var(--color-accent-700);
    --color-divider: color-mix(in srgb, var(--color-neutral-900) 14%, transparent);
    --ink-dim: var(--color-neutral-800);
    --ink-faint: var(--color-neutral-700);
    --accent-ink: var(--color-accent-700);
    --glow: color-mix(in srgb, var(--color-accent-200) 90%, transparent);
    --fall: transparent;
    --shadow-md: 0 0 0 1px var(--color-neutral-300), 0 10px 30px rgba(41, 43, 49, 0.12);
  }
}

html { -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.85;
  background:
    radial-gradient(900px 620px at 88% -140px, var(--glow), transparent 62%),
    radial-gradient(900px 700px at -10% 100%, var(--fall), transparent 55%),
    var(--color-bg);
  background-repeat: no-repeat;
  min-height: 100vh;
  text-wrap: pretty;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent-ink); }
a:hover { color: var(--color-accent); }
:focus-visible { outline: 2px solid var(--color-accent); outline-offset: 2px; }
.wrap { max-width: 1040px; margin: 0 auto; padding: 0 var(--edge); }
.nb { display: inline-block; }

/* header / footer */
.top { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding-block: 18px; }
.brand { font-size: 17px; font-weight: 500; letter-spacing: 0.01em; color: var(--color-text); text-decoration: none; }
.lang { display: flex; border: 1px solid var(--color-divider); border-radius: var(--radius-md); overflow: hidden; font-size: 13px; line-height: 1; }
.lang a { padding: 8px 12px; color: var(--ink-dim); text-decoration: none; }
.lang a + a { border-left: 1px solid var(--color-divider); }
.lang a:hover { color: var(--color-text); background: color-mix(in srgb, var(--color-text) 7%, transparent); }
.lang a[aria-current] { color: var(--accent-ink); background: color-mix(in srgb, var(--color-accent) 12%, transparent); pointer-events: none; }

.rule { height: 1px; border: 0; margin: 0;
  background: linear-gradient(to right, transparent, var(--color-divider) 48px calc(100% - 48px), transparent); }

.foot { padding-block: 36px 48px; display: flex; flex-wrap: wrap; justify-content: space-between; gap: 16px 32px; font-size: 13px; color: var(--ink-faint); }
.foot nav { display: flex; flex-wrap: wrap; gap: 8px 20px; }
.foot a { color: var(--ink-dim); text-decoration: none; }
.foot a:hover { color: var(--color-text); }

/* kicker */
.kicker { font-size: 12px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--accent-ink); margin: 0 0 14px; font-feature-settings: "tnum" 1; }

/* hero */
.hero { display: grid; gap: 48px; padding-block: 56px 72px; align-items: center; }
@media (min-width: 820px) { .hero { grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); padding-block: 96px 112px; } }
.catch { font-size: clamp(30px, 6.4vw, 50px); line-height: 1.42; letter-spacing: 0.01em; margin: 0; }
.lead { font-size: 17px; color: var(--ink-dim); margin: 24px 0 0; max-width: 30em; }
.cta { margin-top: 32px; display: flex; flex-wrap: wrap; align-items: center; gap: 12px 18px; }
.cta .btn { font-size: 16px; padding: 13px 22px; }
.cta small { font-size: 13px; color: var(--ink-faint); }

/* phone mock */
.phone {
  justify-self: center;
  width: min(270px, 70vw); aspect-ratio: 9 / 19.5;
  border-radius: 42px; padding: 10px;
  background: var(--color-neutral-900);
  box-shadow: var(--shadow-md);
}
@media (prefers-color-scheme: light) { .phone { background: var(--color-neutral-300); } }
.screen {
  height: 100%; border-radius: 33px; background: var(--color-bg);
  display: flex; flex-direction: column; padding: 64px 24px 28px; position: relative; overflow: hidden;
}
.screen::before { content: ""; position: absolute; top: 11px; left: 50%; translate: -50% 0; width: 78px; height: 22px; border-radius: 99px; background: var(--color-neutral-900); }
@media (prefers-color-scheme: light) { .screen::before { background: var(--color-neutral-300); } }
.big { display: flex; align-items: baseline; gap: 2px; font-weight: 500; font-feature-settings: "tnum" 1; }
.big b { font-size: 84px; line-height: 0.95; letter-spacing: -0.04em; font-weight: 500; }
.big span { font-size: 30px; }
.screen .said { font-size: 17px; color: var(--ink-dim); margin-top: 10px; }
.screen .meta { margin-top: auto; font-size: 12px; line-height: 1.8; color: var(--ink-faint); }
.screen .btns { display: flex; gap: 8px; margin-top: 16px; }
.screen .btns span { flex: 1; text-align: center; font-size: 12px; padding: 9px 0; border-radius: var(--radius-lg); border: 1px solid var(--color-divider); color: var(--ink-dim); }
.screen .btns span:first-child { border-color: var(--color-accent); color: var(--accent-ink); }

/* sections */
.section { padding-block: 72px; }
.h2 { font-size: clamp(22px, 4vw, 30px); line-height: 1.5; margin: 0 0 36px; letter-spacing: 0.01em; }
.steps { list-style: none; margin: 0; padding: 0; display: grid; gap: 40px; }
@media (min-width: 820px) { .steps { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 40px; } }
.steps .n { font-size: 13px; color: var(--accent-ink); font-feature-settings: "tnum" 1; letter-spacing: 0.08em; }
.steps h3 { font-size: 18px; line-height: 1.55; margin: 8px 0 10px; letter-spacing: 0.01em; }
.steps p { margin: 0; color: var(--ink-dim); font-size: 15px; }
.key { display: inline-block; min-width: 1.6em; text-align: center; padding: 0 0.3em; border: 1px solid var(--color-divider); border-radius: var(--radius-sm); color: var(--color-text); }

.band { background: var(--color-section); color: var(--color-neutral-100); }
@media (prefers-color-scheme: light) { .band { background: var(--color-accent-200); color: var(--color-neutral-900); } }
.band .wrap { padding-block: 72px; }
.band blockquote { margin: 0; font-size: clamp(21px, 3.6vw, 28px); line-height: 1.75; font-weight: 500; max-width: 24em; }
.band cite { display: block; margin-top: 20px; font-size: 13px; font-style: normal; opacity: 0.8; }

.facts { list-style: none; margin: 0; padding: 0; display: grid; gap: 0; max-width: 40em; }
.facts li { position: relative; padding: 16px 0 16px 30px; border-bottom: 1px solid var(--color-divider); font-size: 16px; }
.facts li::before { content: ""; position: absolute; left: 0; top: calc(16px + 0.92em); width: 14px; height: 1px; background: var(--color-accent); }
.facts li small { display: block; font-size: 14px; color: var(--ink-dim); }

/* document pages */
.doc { padding-block: 56px 80px; max-width: 40em; }
.doc h1 { font-size: clamp(26px, 5vw, 36px); line-height: 1.4; margin: 0 0 28px; letter-spacing: 0.01em; }
.doc .intro { color: var(--ink-dim); margin: 0 0 36px; }
.doc h2 { font-size: 17px; line-height: 1.6; margin: 36px 0 8px; letter-spacing: 0.01em; }
.doc p { margin: 0; }
.doc .sig { margin-top: 48px; padding-top: 20px; border-top: 1px solid var(--color-divider); font-size: 14px; color: var(--ink-dim); line-height: 2; }
.doc .alt { margin-top: 28px; font-size: 14px; }

.faq { margin: 0; }
.faq .q { font-size: 17px; font-weight: 500; line-height: 1.6; margin: 0 0 8px; display: grid; grid-template-columns: 1.6em minmax(0, 1fr); }
.faq .a { margin: 0 0 32px; color: var(--ink-dim); display: grid; grid-template-columns: 1.6em minmax(0, 1fr); }
.faq .q::before { content: "Q"; color: var(--accent-ink); }
.faq .a::before { content: "A"; color: var(--ink-faint); }
.contact { margin-top: 56px; padding: 24px; border-radius: var(--radius-lg); background: var(--color-surface); }
.contact h2 { margin: 0 0 6px; }
.contact p { color: var(--ink-dim); font-size: 15px; }
.contact .btn { margin-top: 16px; font-size: 15px; padding: 11px 18px; }