:root {
  color-scheme: light dark;
  --bg: #fafaf9;
  --surface: #ffffff;
  --text: #1c1917;
  --muted: #57534e;
  --line: #e7e5e4;
  --accent: #2563eb;
  --accent-text: #ffffff;
  --accent-soft: #eff4ff;
  --warn-bg: #fef9c3;
  --warn-line: #eab308;
  --warn-text: #422006;
  --kbd-bg: #f5f5f4;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #161514;
    --surface: #1f1e1d;
    --text: #f5f5f4;
    --muted: #b8b2ad;
    --line: #34312f;
    --accent: #7aa2ff;
    --accent-text: #0b1220;
    --accent-soft: #1b2338;
    --warn-bg: #3a3212;
    --warn-line: #ca8a04;
    --warn-text: #fef3c7;
    --kbd-bg: #2a2826;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.7 system-ui, -apple-system, "Segoe UI", "Apple SD Gothic Neo", "Malgun Gothic", "Hiragino Sans", "Yu Gothic UI", "Noto Sans CJK KR", sans-serif;
  word-break: keep-all;
  overflow-wrap: anywhere;
}
:lang(ja) body, body:lang(ja) { word-break: normal; line-break: strict; }
a { color: var(--accent); }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }
img { max-width: 100%; height: auto; }
.wrap { max-width: 760px; margin: 0 auto; padding: 0 16px; }
.skip { position: absolute; left: -9999px; }
.skip:focus { left: 16px; top: 8px; background: var(--surface); padding: 6px 12px; z-index: 10; }

.site-head { border-bottom: 1px solid var(--line); background: var(--surface); }
.head-row { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 56px; }
.brand { display: inline-flex; align-items: center; gap: 8px; color: var(--text); text-decoration: none; font-weight: 700; font-size: 18px; }
.langs { font-size: 14px; white-space: nowrap; }
.langs a { text-decoration: none; padding: 4px 2px; color: var(--muted); }
.langs a[aria-current="page"] { color: var(--text); font-weight: 700; }

h1, h2, h3 { line-height: 1.35; }
h2 { font-size: 24px; margin: 0 0 20px; }
h3 { font-size: 18px; margin: 0 0 6px; }
section { padding: 48px 0; }
section + section { border-top: 1px solid var(--line); }

.hero { text-align: center; padding: 56px 0 48px; }
.hero-icon { display: block; margin: 0 auto 12px; }
.hero h1 { font-size: 40px; margin: 0 0 12px; letter-spacing: -0.01em; }
.tagline { font-size: 22px; font-weight: 700; margin: 0 auto 12px; max-width: 32em; }
.sub { color: var(--muted); margin: 0 auto 24px; max-width: 34em; }
.install { margin: 0 0 12px; }
.cta {
  display: inline-block; padding: 12px 28px; border-radius: 10px;
  background: var(--accent); color: var(--accent-text); font-weight: 700; font-size: 17px; text-decoration: none;
}
.cta:hover { filter: brightness(1.08); }
.install.pending { display: inline-block; padding: 10px 18px; border: 1px dashed var(--line); border-radius: 10px; background: var(--surface); }
.facts { font-size: 14px; color: var(--muted); margin: 0; }
.chrome-only { font-size: 13px; color: var(--muted); margin: 4px 0 0; }

.step-list, .principle-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 16px; }
.step-list li { display: flex; gap: 14px; align-items: flex-start; }
.step-list p { margin: 0; }
.num {
  flex: none; display: inline-grid; place-items: center; width: 28px; height: 28px; border-radius: 50%;
  background: var(--accent-soft); color: var(--accent); font-weight: 700; font-size: 14px; margin-top: 2px;
}
.keys { margin-left: 6px; }
kbd {
  display: inline-block; min-width: 1.8em; padding: 0 6px; margin-right: 4px; border: 1px solid var(--line); border-bottom-width: 2px;
  border-radius: 6px; background: var(--kbd-bg); font: 600 13px/1.6 ui-monospace, SFMono-Regular, Menlo, monospace; text-align: center;
}
.principle-list li { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 18px 18px 14px; }
.principle-list h3 { display: flex; gap: 10px; align-items: flex-start; }
.principle-list p { margin: 0 0 8px; }
.in-sayover { background: var(--accent-soft); border-radius: 8px; padding: 6px 10px; }
.basis { font-size: 14px; color: var(--muted); }
.basis span { font-weight: 700; margin-right: 4px; }

.screen-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 16px; }
.screen-list img { border: 1px solid var(--line); border-radius: 8px; display: block; }

.backup-section { padding: 32px 0; }
.backup { background: var(--warn-bg); border: 1px solid var(--warn-line); border-left-width: 6px; border-radius: 10px; padding: 18px 20px; color: var(--warn-text); }
.backup h2 { font-size: 20px; margin: 0 0 8px; }
.backup p { margin: 0; }

.notes ul { margin: 0; padding-left: 1.2em; }
.notes li { margin-bottom: 6px; color: var(--muted); }

.site-foot { border-top: 1px solid var(--line); padding: 24px 0 40px; font-size: 14px; color: var(--muted); }
.foot-row { display: flex; flex-wrap: wrap; gap: 8px 20px; align-items: center; }

.policy { padding-top: 24px; padding-bottom: 48px; }
.policy .back { font-size: 14px; margin: 0 0 8px; }
.policy h1 { font-size: 28px; }
.policy h2 { font-size: 20px; margin: 32px 0 10px; }
.policy table { width: 100%; border-collapse: collapse; font-size: 14px; display: block; overflow-x: auto; }
.policy th, .policy td { border: 1px solid var(--line); padding: 6px 8px; text-align: left; vertical-align: top; min-width: 7em; }
.policy th { background: var(--surface); }
.policy code { font-size: 0.92em; background: var(--kbd-bg); padding: 0 4px; border-radius: 4px; }

@media (max-width: 480px) {
  .hero h1 { font-size: 32px; }
  .tagline { font-size: 19px; }
  h2 { font-size: 21px; }
  .principle-list li { padding: 14px; }
}