:root {
  color-scheme: dark;
  --bg: #0b0b0e;
  --card: rgba(255, 255, 255, 0.06);
  --card-border: rgba(255, 255, 255, 0.10);
  --text: rgba(255, 255, 255, 0.92);
  --muted: rgba(255, 255, 255, 0.62);
  --muted2: rgba(255, 255, 255, 0.40);
  --link: rgba(255, 255, 255, 0.92);
  --link-hover: rgba(255, 255, 255, 0.75);
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
}

body {
  margin: 0;
  font-family: "Noto Sans JP", ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica,
    Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Yu Gothic", Meiryo, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background: radial-gradient(900px 500px at 20% 0%, rgba(255, 255, 255, 0.06), transparent 60%),
    radial-gradient(700px 420px at 80% 100%, rgba(255, 255, 255, 0.04), transparent 55%),
    var(--bg);
  color: var(--text);
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover {
  color: var(--link-hover);
  text-decoration: underline;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 48px 20px;
}

/* ---- Hero ---- */
.hero {
  text-align: center;
  padding: 48px 0 36px;
}

.hero-title {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0;
}

.hero-sub {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.7;
}

.sp-only { display: none; }
@media (max-width: 480px) {
  .sp-only { display: inline; }
}

/* ---- Card ---- */
.card {
  margin-top: 28px;
  padding: 28px 24px;
  border-radius: 18px;
  background: var(--card);
  border: 1px solid var(--card-border);
  box-shadow: 0 18px 55px rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(18px);
}

.card-heading {
  font-size: 16px;
  font-weight: 700;
  margin: 0 0 20px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.card-desc {
  margin: 0;
  color: var(--muted);
  line-height: 1.9;
  font-size: 14px;
}

.card p, .card li {
  color: var(--muted);
  line-height: 1.8;
  font-size: 14px;
}

/* ---- Features ---- */
.features {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.feature {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}

.feature-icon {
  font-size: 28px;
  line-height: 1;
  flex-shrink: 0;
  margin-top: 2px;
}

.feature h3 {
  font-size: 15px;
  font-weight: 700;
  margin: 0 0 4px;
}

.feature p {
  margin: 0;
}

/* ---- Steps ---- */
.steps {
  padding-left: 1.4em;
  margin: 0;
}

.steps li {
  padding: 6px 0;
}

.steps li + li {
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

/* ---- Footer ---- */
.footer {
  margin-top: 36px;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.10);
  color: var(--muted2);
  font-size: 12px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.footer-links {
  display: flex;
  gap: 10px;
  align-items: center;
}

.footer-links span {
  color: var(--muted2);
  font-size: 10px;
}

/* ---- Shared (sub-pages) ---- */
.header {
  margin-bottom: 24px;
}

.small-muted {
  color: var(--muted2);
  font-size: 12px;
}

.lead {
  margin: 0;
  color: var(--muted);
  line-height: 1.75;
}

.h1 {
  font-size: 34px;
  letter-spacing: -0.02em;
  margin: 12px 0 10px;
}

.section-title {
  margin: 0 0 12px;
}

.card h2.section-title {
  font-size: 18px;
  text-transform: none;
  letter-spacing: normal;
  color: var(--text);
}

ol, ul {
  padding-left: 1.2em;
}

hr {
  border: 0;
  border-top: 1px solid rgba(255, 255, 255, 0.10);
  margin: 18px 0;
}