:root {
  --bg: #0a0b14;
  --bg-raise: #11131f;
  --ink: #f2f3f7;
  --ink-dim: #b4b9c8;
  --ink-faint: #6d7385;
  --rec: #ff2d55;
  --cyan: #38e1ff;
  --line: rgba(255, 255, 255, 0.09);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  background:
    radial-gradient(1100px 500px at 85% -10%, rgba(56, 225, 255, 0.07), transparent 60%),
    radial-gradient(900px 600px at -10% 105%, rgba(255, 45, 85, 0.06), transparent 55%),
    var(--bg);
  color: var(--ink-dim);
  font-family: "Zen Kaku Gothic New", "Hiragino Kaku Gothic ProN", sans-serif;
  font-size: 16px;
  line-height: 1.9;
  letter-spacing: 0.02em;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

.mono {
  font-family: "IBM Plex Mono", "SF Mono", Menlo, monospace;
  letter-spacing: 0.14em;
}

.wrap {
  width: min(680px, 100% - 48px);
  margin-inline: auto;
}

/* ── header ─────────────────────────────── */

header {
  border-bottom: 1px solid var(--line);
  padding: 20px 0;
}

header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 700;
  font-size: 15px;
}

.rec-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--rec);
  box-shadow: 0 0 12px rgba(255, 45, 85, 0.8);
  animation: blink 2.4s ease-in-out infinite;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.35; }
}

@media (prefers-reduced-motion: reduce) {
  .rec-dot { animation: none; }
}

header nav a {
  color: var(--ink-faint);
  text-decoration: none;
  font-size: 12px;
}

header nav a:hover {
  color: var(--cyan);
}

/* ── main ───────────────────────────────── */

main {
  flex: 1;
  padding: 72px 0 96px;
}

.kicker {
  color: var(--cyan);
  font-size: 11px;
  text-transform: uppercase;
  margin-bottom: 18px;
}

h1 {
  color: var(--ink);
  font-size: clamp(30px, 6vw, 44px);
  font-weight: 900;
  line-height: 1.35;
  letter-spacing: 0.01em;
  margin-bottom: 14px;
}

.lede {
  color: var(--ink-faint);
  font-size: 14px;
  margin-bottom: 64px;
}

.lede a {
  color: var(--cyan);
  text-decoration: none;
}

section {
  margin-bottom: 56px;
}

.sec-no {
  color: var(--ink-faint);
  font-size: 11px;
  display: block;
  margin-bottom: 6px;
}

h2 {
  color: var(--ink);
  font-size: 20px;
  font-weight: 700;
  line-height: 1.5;
  margin-bottom: 14px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
}

p + p {
  margin-top: 12px;
}

ul {
  list-style: none;
}

ul li {
  padding-left: 18px;
  position: relative;
  margin-bottom: 10px;
}

ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.85em;
  width: 7px;
  height: 2px;
  background: var(--cyan);
}

strong {
  color: var(--ink);
  font-weight: 700;
}

a {
  color: var(--cyan);
}

.note {
  background: var(--bg-raise);
  border: 1px solid var(--line);
  border-left: 3px solid var(--rec);
  border-radius: 8px;
  padding: 16px 20px;
  font-size: 14px;
  color: var(--ink-faint);
}

/* ── FAQ (support page) ─────────────────── */

details {
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg-raise);
  margin-bottom: 12px;
  overflow: hidden;
}

summary {
  cursor: pointer;
  list-style: none;
  padding: 16px 20px;
  color: var(--ink);
  font-weight: 700;
  font-size: 15px;
  display: flex;
  align-items: baseline;
  gap: 12px;
}

summary::-webkit-details-marker { display: none; }

summary::before {
  content: "Q";
  color: var(--rec);
  font-weight: 700;
  flex-shrink: 0;
}

details .a {
  padding: 0 20px 18px 44px;
  font-size: 15px;
}

.contact-card {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: linear-gradient(160deg, rgba(56, 225, 255, 0.06), transparent 45%), var(--bg-raise);
  padding: 28px;
  text-align: center;
}

.contact-card .mail {
  display: inline-block;
  margin-top: 10px;
  color: var(--ink);
  font-size: 18px;
  font-weight: 700;
  text-decoration: none;
  border-bottom: 2px solid var(--cyan);
  padding-bottom: 2px;
}

/* ── footer ─────────────────────────────── */

footer {
  border-top: 1px solid var(--line);
  padding: 28px 0;
  font-size: 12px;
  color: var(--ink-faint);
}

footer .wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  align-items: center;
  justify-content: space-between;
}

footer a {
  color: var(--ink-faint);
  text-decoration: none;
}

footer a:hover {
  color: var(--cyan);
}