:root {
  color-scheme: light;
  font-family: Inter, ui-rounded, "Segoe UI", system-ui, sans-serif;
  color: #18213a;
  background: #bff4ff;
  line-height: 1.6;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top, rgba(255,255,255,.9), transparent 34rem),
    linear-gradient(180deg, #bff4ff 0%, #78d5f0 100%);
}

a { color: #164fc9; }
a:hover { color: #0c358d; }

.shell {
  width: min(880px, calc(100% - 28px));
  margin: 0 auto;
  padding: 28px 0 54px;
}

.site-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 18px;
}

.site-header img {
  width: 66px;
  height: 66px;
  border-radius: 18px;
  box-shadow: 0 5px 0 rgba(17, 17, 17, .2);
}

.site-header strong { display: block; font-size: 1.35rem; }
.site-header span { color: #43506d; }

.card {
  background: rgba(255, 255, 255, .97);
  border: 3px solid #111;
  border-radius: 26px;
  box-shadow: 0 10px 0 rgba(17, 17, 17, .18);
  padding: clamp(22px, 5vw, 46px);
}

h1, h2 { line-height: 1.18; color: #111; }
h1 { margin: 0 0 8px; font-size: clamp(2rem, 6vw, 3.2rem); }
h2 { margin: 2rem 0 .55rem; font-size: 1.35rem; }
p, li { max-width: 72ch; }
.meta { margin-top: 0; color: #59647b; }
.notice {
  margin: 22px 0;
  padding: 15px 17px;
  background: #eef2ff;
  border: 2px solid #111;
  border-radius: 15px;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin-top: 28px;
  padding-top: 20px;
  border-top: 1px solid #cbd3df;
}

nav a { font-weight: 700; }
.button {
  display: inline-block;
  margin-top: 8px;
  padding: 10px 16px;
  border: 2px solid #111;
  border-radius: 12px;
  background: #8791ff;
  color: #111;
  font-weight: 900;
  text-decoration: none;
  box-shadow: 0 4px 0 #111;
}

footer { padding: 18px 4px 0; color: #34415f; font-size: .92rem; }

@media (max-width: 520px) {
  .shell { width: min(100% - 18px, 880px); padding-top: 16px; }
  .card { border-radius: 20px; border-width: 2px; }
}