:root {
  color-scheme: light;
  --ink: #171717;
  --muted: #625f5a;
  --paper: #fffdf8;
  --panel: #ffffff;
  --line: #ded8ce;
  --red: #e62117;
  --red-dark: #b91c14;
  --blue: #155eef;
  --shadow: 0 20px 50px rgba(48, 37, 25, 0.08);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }
[id] { scroll-margin-top: 90px; }

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 10% 0%, rgba(230, 33, 23, 0.08), transparent 28rem),
    var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", sans-serif;
  line-height: 1.75;
}

a { color: var(--blue); text-underline-offset: 0.18em; }
a:hover { text-decoration-thickness: 2px; }
a:focus-visible, .button:focus-visible {
  outline: 3px solid #ffbf47;
  outline-offset: 4px;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -5rem;
  z-index: 10;
  padding: 0.7rem 1rem;
  color: #fff;
  background: var(--ink);
}
.skip-link:focus { top: 1rem; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  border-bottom: 1px solid rgba(222, 216, 206, 0.85);
  background: rgba(255, 253, 248, 0.92);
  backdrop-filter: blur(12px);
}

.nav {
  width: min(1120px, calc(100% - 2rem));
  margin: 0 auto;
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.brand { color: var(--ink); font-weight: 800; text-decoration: none; letter-spacing: -0.02em; }
.nav-links { display: flex; flex-wrap: wrap; gap: 1rem; font-size: 0.92rem; }
.nav-links a { color: var(--ink); }

main { width: min(1120px, calc(100% - 2rem)); margin: 0 auto; }

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(280px, 0.65fr);
  gap: clamp(2rem, 6vw, 5rem);
  align-items: center;
  min-height: 64vh;
  padding: 5rem 0 3.5rem;
}

.eyebrow {
  margin: 0 0 0.8rem;
  color: var(--red-dark);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

h1, h2, h3 { line-height: 1.25; letter-spacing: -0.035em; }
h1 { max-width: 16ch; margin: 0; font-size: clamp(2.6rem, 7vw, 5.6rem); }
h2 { margin-top: 0; font-size: clamp(1.7rem, 4vw, 2.7rem); }
h3 { font-size: 1.15rem; }

.lead { max-width: 46rem; margin: 1.4rem 0 2rem; color: var(--muted); font-size: 1.12rem; }
.actions { display: flex; flex-wrap: wrap; gap: 0.8rem; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0.7rem 1rem;
  border: 1px solid var(--ink);
  border-radius: 999px;
  color: #fff;
  background: var(--ink);
  font-weight: 750;
  text-decoration: none;
}
.button.secondary { color: var(--ink); background: transparent; }

.api-card {
  padding: 2rem;
  border: 1px solid var(--line);
  border-radius: 28px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.youtube-mark {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  font-weight: 800;
}
.play {
  width: 44px;
  height: 31px;
  display: inline-grid;
  place-items: center;
  border-radius: 9px;
  color: #fff;
  background: var(--red);
  font-size: 0.9rem;
}
.status { display: inline-block; margin-top: 1.2rem; padding: 0.35rem 0.65rem; border-radius: 999px; background: #f0f0ed; font-size: 0.82rem; font-weight: 700; }

.section { padding: 4rem 0; border-top: 1px solid var(--line); }
.section > p { max-width: 52rem; }
.grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1rem; margin-top: 2rem; }
.card { padding: 1.5rem; border: 1px solid var(--line); border-radius: 20px; background: var(--panel); }
.card p { margin-bottom: 0; color: var(--muted); }

.flow { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 0.75rem; margin-top: 2rem; padding: 0; list-style: none; counter-reset: step; }
.flow li { padding: 1.25rem; border: 1px solid var(--line); border-radius: 18px; background: #fff; }
.flow li::before { counter-increment: step; content: counter(step); display: grid; place-items: center; width: 2rem; height: 2rem; margin-bottom: 0.8rem; border-radius: 50%; color: #fff; background: var(--ink); font-weight: 800; }

.policy { width: min(800px, calc(100% - 2rem)); margin: 0 auto; padding: 4rem 0 6rem; }
.policy h1 { max-width: none; font-size: clamp(2.3rem, 6vw, 4.5rem); }
.policy h2 { margin-top: 3rem; font-size: 1.55rem; }
.policy li + li { margin-top: 0.7rem; }
.notice { margin: 2rem 0; padding: 1rem 1.2rem; border-left: 5px solid var(--red); background: #fff; }

.site-footer { border-top: 1px solid var(--line); }
.footer-inner { width: min(1120px, calc(100% - 2rem)); margin: 0 auto; padding: 2rem 0 3rem; display: flex; flex-wrap: wrap; justify-content: space-between; gap: 1rem; color: var(--muted); font-size: 0.9rem; }
.footer-links { display: flex; flex-wrap: wrap; gap: 1rem; }

@media (max-width: 800px) {
  .hero { grid-template-columns: 1fr; min-height: auto; padding-top: 3.5rem; }
  .grid { grid-template-columns: 1fr; }
  .flow { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 520px) {
  .nav { align-items: flex-start; padding: 0.9rem 0; }
  .nav-links { gap: 0.6rem; }
  .flow { grid-template-columns: 1fr; }
  .actions { flex-direction: column; align-items: stretch; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}