:root {
  --bg: #f7f7fb;
  --card: #ffffff;
  --text: #1d1d28;
  --muted: #5d6070;
  --line: #e2e3ec;
  --accent: #5b5bd6;
  --accent-soft: #ececfb;
  --warn-bg: #fff4e0;
  --warn-text: #7a4a00;
  --code-bg: #f0f0f6;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #14151c;
    --card: #1e2029;
    --text: #ececf3;
    --muted: #a4a7b8;
    --line: #33364a;
    --accent: #9b9bff;
    --accent-soft: #2a2c44;
    --warn-bg: #3a2c12;
    --warn-text: #ffd58a;
    --code-bg: #2a2d3c;
  }
}
:root[data-theme="dark"] {
  --bg: #14151c;
  --card: #1e2029;
  --text: #ececf3;
  --muted: #a4a7b8;
  --line: #33364a;
  --accent: #9b9bff;
  --accent-soft: #2a2c44;
  --warn-bg: #3a2c12;
  --warn-text: #ffd58a;
  --code-bg: #2a2d3c;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Malgun Gothic", "Apple SD Gothic Neo", sans-serif;
  line-height: 1.65;
  font-size: 16px;
}
.wrap { max-width: 720px; margin: 0 auto; padding: 0 16px 48px; }
header.top {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 18px 0 12px; border-bottom: 1px solid var(--line); margin-bottom: 8px;
}
header.top h1 { font-size: 1.35rem; margin: 0; }
.back {
  color: var(--accent); text-decoration: none; font-weight: 600;
  padding: 8px 12px; border: 1px solid var(--line); border-radius: 8px; background: var(--card);
  white-space: nowrap;
}
section.card {
  background: var(--card); border: 1px solid var(--line); border-radius: 12px;
  padding: 18px; margin: 14px 0;
}
h2 { font-size: 1.15rem; margin: 0 0 10px; }
p { margin: 8px 0; }
ol, ul { padding-left: 1.3em; margin: 8px 0; }
li { margin: 6px 0; }
.step { display: flex; gap: 10px; align-items: flex-start; margin: 10px 0; }
.num {
  flex: 0 0 auto; width: 28px; height: 28px; border-radius: 50%;
  background: var(--accent); color: #fff; font-weight: 700;
  display: flex; align-items: center; justify-content: center; font-size: 0.9rem;
}
code, .code {
  background: var(--code-bg); padding: 2px 6px; border-radius: 6px;
  font-family: ui-monospace, Consolas, monospace; font-size: 0.92em; word-break: break-all;
}
.note {
  background: var(--accent-soft); border-radius: 10px; padding: 12px 14px; margin: 10px 0;
}
.warn {
  background: var(--warn-bg); color: var(--warn-text); border-radius: 10px;
  padding: 12px 14px; margin: 10px 0; font-weight: 500;
}
details {
  border-top: 1px solid var(--line); padding: 10px 0;
}
details:first-of-type { border-top: none; }
summary { cursor: pointer; font-weight: 700; }
details p { margin: 6px 0 4px; }
.muted { color: var(--muted); font-size: 0.92rem; }
a { color: var(--accent); }