:root {
  --text: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
  --bg: #f8fafc;
  --blue: #155eef;
  --blue-dark: #0f46c7;
  --green: #16a34a;
  --max: 980px;
  --radius: 18px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  color: var(--text);
  background: #fff;
  line-height: 1.75;
}

a { color: inherit; text-decoration: none; }
.container { width: min(100% - 40px, var(--max)); margin: 0 auto; }

header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, .96);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
}

.nav {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 21px;
  font-weight: 800;
  letter-spacing: -.03em;
}

.logo {
  width: 38px;
  height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 11px;
  background: var(--blue);
  color: #fff;
  font-weight: 800;
}

.nav-links { display: flex; align-items: center; gap: 24px; color: var(--muted); font-size: 15px; font-weight: 700; }
.nav-links a:hover, .footer-links a:hover { color: var(--blue); }
.nav-actions { display: flex; align-items: center; gap: 10px; }

.language-switcher {
  height: 42px;
  padding: 0 10px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
  color: var(--text);
  font-weight: 700;
  outline: none;
  cursor: pointer;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0 18px;
  border: 1px solid var(--blue);
  border-radius: 11px;
  background: var(--blue);
  color: #fff;
  font-weight: 800;
  white-space: nowrap;
}

.hero { padding: 72px 0 44px; background: linear-gradient(180deg, #f8fbff 0%, #fff 100%); }
.eyebrow { display: inline-flex; margin-bottom: 18px; padding: 7px 12px; border-radius: 999px; background: #eaf1ff; color: var(--blue-dark); font-size: 14px; font-weight: 800; }
h1 { max-width: 760px; font-size: clamp(38px, 5vw, 56px); line-height: 1.15; letter-spacing: -.05em; }
.hero p { max-width: 780px; margin-top: 20px; color: var(--muted); font-size: 18px; }
.meta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 24px; color: var(--muted); font-size: 14px; }
.meta span { padding: 7px 10px; border: 1px solid var(--line); border-radius: 999px; background: #fff; }

main { padding: 52px 0 80px; }
.layout { display: grid; grid-template-columns: 250px minmax(0, 1fr); gap: 34px; align-items: start; }
.toc { position: sticky; top: 96px; padding: 18px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg); }
.toc h2 { margin-bottom: 12px; font-size: 15px; }
.toc a { display: block; padding: 8px 0; border-bottom: 1px solid rgba(226, 232, 240, .8); color: var(--muted); font-size: 14px; }
.toc a:last-child { border-bottom: none; }
.toc a:hover { color: var(--blue); }
.content { display: grid; gap: 18px; }
.card { padding: 28px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; scroll-margin-top: 96px; }
.card.notice { border-color: #dbeafe; background: var(--bg); }
.card h2 { margin-bottom: 12px; font-size: 26px; line-height: 1.25; letter-spacing: -.03em; }
.card h3 { margin: 20px 0 8px; font-size: 18px; }
p { margin-bottom: 12px; color: var(--muted); }
ul { display: grid; gap: 9px; margin: 12px 0 0; padding-left: 20px; color: var(--muted); }
strong { color: var(--text); }
.good-list { padding-left: 0; }
.good-list li { position: relative; padding-left: 28px; list-style: none; }
.good-list li::before { content: "✓"; position: absolute; top: 0; left: 0; color: var(--green); font-weight: 900; }

.contact-box { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-top: 18px; }
.contact-item { padding: 18px; border: 1px solid var(--line); border-radius: 16px; background: var(--bg); }
.contact-item span { display: inline-flex; align-items: center; justify-content: center; width: 34px; height: 34px; margin-bottom: 12px; border-radius: 10px; background: #eaf1ff; color: var(--blue-dark); font-size: 18px; }
.contact-item h3 { margin: 0 0 6px; font-size: 17px; }
.contact-item p { margin: 0; font-size: 14px; }
.contact-item a { color: var(--blue); font-weight: 800; }

.support-float { position: fixed; right: 0; top: 50%; z-index: 120; width: 44px; height: 132px; display: flex; align-items: center; justify-content: center; overflow: hidden; border-radius: 16px 0 0 16px; background: var(--blue); color: #fff; box-shadow: 0 18px 42px rgba(21, 94, 239, .28); transform: translateY(-50%); transition: .2s ease; }
.support-float:hover { width: 48px; background: var(--blue-dark); }
.support-inner { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 7px; line-height: 1; }
.support-icon { font-size: 17px; line-height: 1; }
.support-text { writing-mode: vertical-rl; text-orientation: mixed; font-size: 14px; font-weight: 900; letter-spacing: .14em; }

footer { padding: 34px 0; border-top: 1px solid var(--line); color: var(--muted); font-size: 14px; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 20px; flex-wrap: wrap; }
.footer-links { display: flex; gap: 18px; flex-wrap: wrap; }

@media (max-width: 840px) {
  .nav-links { display: none; }
  .layout { grid-template-columns: 1fr; }
  .toc { position: static; }
}

@media (max-width: 620px) {
  .container { width: min(100% - 28px, var(--max)); }
  .hero { padding: 54px 0 34px; }
  h1 { font-size: clamp(34px, 10vw, 44px); }
  .hero p { font-size: 16px; }
  .card { padding: 22px; }
  .card h2 { font-size: 23px; }
  .nav-actions .btn { display: none; }
  .contact-box { grid-template-columns: 1fr; }
  .support-float { top: auto; right: 14px; bottom: calc(18px + env(safe-area-inset-bottom)); width: 46px; height: 46px; border-radius: 50%; transform: none; }
  .support-float:hover { width: 46px; }
  .support-text { display: none; }
  .support-icon { font-size: 20px; }
  .footer-inner { flex-direction: column; justify-content: center; text-align: center; }
  .footer-links { width: 100%; justify-content: center; gap: 12px 18px; }
}