:root {
  color-scheme: light;
  --ink: #112b2b;
  --muted: #5f7575;
  --line: rgba(42, 143, 143, 0.16);
  --aqua: #13bfc2;
  --aqua-dark: #087d83;
  --mint: #dff9f3;
  --paper: rgba(255, 255, 255, 0.88);
  --shadow: 0 24px 70px rgba(12, 107, 112, 0.12);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
  line-height: 1.75;
  color: var(--ink);
  background:
    radial-gradient(circle at 18% 8%, rgba(89, 228, 220, 0.28), transparent 34%),
    radial-gradient(circle at 86% 16%, rgba(179, 242, 225, 0.46), transparent 30%),
    linear-gradient(145deg, #f8fffe 0%, #eaf9f8 52%, #f8fcfb 100%);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.32;
  background-image:
    linear-gradient(rgba(19, 191, 194, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(19, 191, 194, 0.06) 1px, transparent 1px);
  background-size: 34px 34px;
  mask-image: linear-gradient(to bottom, black, transparent 78%);
}

a { color: var(--aqua-dark); }
a:hover { color: #055b60; }

.site-shell {
  position: relative;
  width: min(920px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 48px;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 14px 6px 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.brand-mark {
  display: grid;
  width: 46px;
  height: 46px;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.86);
  border-radius: 15px;
  font-size: 25px;
  background: linear-gradient(145deg, rgba(255,255,255,0.94), rgba(199,247,239,0.82));
  box-shadow: 0 10px 24px rgba(20, 147, 151, 0.17);
}

.nav { display: flex; flex-wrap: wrap; gap: 10px; }
.nav a {
  padding: 8px 13px;
  border-radius: 999px;
  color: var(--muted);
  text-decoration: none;
  font-weight: 700;
}
.nav a:hover, .nav a[aria-current="page"] {
  color: var(--aqua-dark);
  background: rgba(255, 255, 255, 0.7);
}

.card {
  padding: clamp(24px, 5vw, 52px);
  border: 1px solid rgba(255, 255, 255, 0.92);
  border-radius: 28px;
  background: var(--paper);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--aqua-dark);
  font-size: 13px;
  font-weight: 850;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1, h2, h3 { line-height: 1.28; }
h1 { margin: 0; font-size: clamp(32px, 7vw, 54px); letter-spacing: -0.035em; }
h2 { margin: 34px 0 10px; font-size: 22px; }
h3 { margin: 22px 0 8px; font-size: 18px; }
p { margin: 10px 0; }

.lead {
  max-width: 700px;
  margin-top: 18px;
  color: var(--muted);
  font-size: 18px;
}

.meta {
  display: inline-flex;
  margin-top: 18px;
  padding: 7px 12px;
  border-radius: 999px;
  color: var(--aqua-dark);
  background: var(--mint);
  font-size: 14px;
  font-weight: 750;
}

.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 30px;
}

.action-card {
  min-height: 170px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 22px;
  color: var(--ink);
  text-decoration: none;
  background: rgba(255,255,255,0.7);
  transition: transform 160ms ease, border-color 160ms ease, box-shadow 160ms ease;
}
.action-card:hover {
  transform: translateY(-3px);
  border-color: rgba(19, 191, 194, 0.38);
  box-shadow: 0 15px 32px rgba(12, 107, 112, 0.1);
}
.action-card .icon { display: block; margin-bottom: 16px; font-size: 30px; }
.action-card strong { display: block; font-size: 20px; }
.action-card span { display: block; margin-top: 6px; color: var(--muted); }

.notice {
  margin: 22px 0;
  padding: 16px 18px;
  border-left: 4px solid var(--aqua);
  border-radius: 4px 16px 16px 4px;
  background: rgba(223, 249, 243, 0.72);
}

.policy ul { padding-left: 1.25em; }
.policy li + li { margin-top: 8px; }

/* ── 帮助中心 ── */
.help-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 30px;
}
.help-card {
  min-height: 150px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 20px;
  color: var(--ink);
  text-decoration: none;
  background: rgba(255,255,255,0.72);
  transition: transform 160ms ease, border-color 160ms ease, box-shadow 160ms ease;
}
.help-card:hover {
  transform: translateY(-3px);
  border-color: rgba(19, 191, 194, 0.38);
  box-shadow: 0 15px 32px rgba(12, 107, 112, 0.1);
}
.help-card .icon { display: block; margin-bottom: 14px; font-size: 28px; }
.help-card strong { display: block; font-size: 18px; }
.help-card span { display: block; margin-top: 6px; color: var(--muted); font-size: 14px; }

.steps { margin: 18px 0; padding: 0; list-style: none; counter-reset: step; }
.steps li {
  position: relative;
  margin: 0 0 14px;
  padding: 14px 16px 14px 52px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255,255,255,0.66);
  counter-increment: step;
}
.steps li::before {
  content: counter(step);
  position: absolute;
  left: 14px;
  top: 14px;
  display: grid;
  width: 26px;
  height: 26px;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  background: var(--aqua);
  font-size: 14px;
  font-weight: 800;
}
.steps li strong { display: block; }
.steps li span { color: var(--muted); font-size: 14px; }

.tip {
  margin: 18px 0;
  padding: 14px 16px;
  border-left: 4px solid #f2b93b;
  border-radius: 4px 14px 14px 4px;
  background: rgba(255, 244, 214, 0.72);
  font-size: 14px;
}

.faq details {
  margin: 10px 0;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255,255,255,0.66);
  overflow: hidden;
}
.faq summary {
  padding: 14px 16px;
  cursor: pointer;
  font-weight: 750;
  list-style: none;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "＋"; float: right; color: var(--aqua-dark); font-weight: 800; }
.faq details[open] summary::after { content: "－"; }
.faq details > div { padding: 0 16px 14px; color: var(--muted); font-size: 14.5px; }

.to-top {
  position: fixed;
  right: 22px;
  bottom: 22px;
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 50%;
  color: var(--aqua-dark);
  text-decoration: none;
  font-weight: 800;
  font-size: 18px;
  background: rgba(255,255,255,0.85);
  box-shadow: 0 8px 22px rgba(12, 107, 112, 0.14);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}
.to-top:hover { background: var(--mint); }

.toc {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  margin: 18px 0 26px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255,255,255,0.6);
  font-size: 14px;
}
.toc strong { color: var(--ink); }
.toc a { text-decoration: none; }

@media (max-width: 680px) {
  .help-grid { grid-template-columns: 1fr; }
}

.site-footer {
  padding: 26px 8px 0;
  color: var(--muted);
  text-align: center;
  font-size: 13px;
}
.site-footer a { color: inherit; }

@media (max-width: 680px) {
  .site-shell { width: min(100% - 20px, 920px); padding-top: 12px; }
  .site-header { align-items: flex-start; flex-direction: column; padding: 10px 4px 18px; }
  .nav { width: 100%; }
  .nav a { padding-left: 10px; }
  .card { border-radius: 22px; }
  .grid { grid-template-columns: 1fr; }
  .lead { font-size: 16px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .action-card { transition: none; }
}