:root {
  --blue: #1a73e8;
  --blue-dark: #0b57d0;
  --blue-soft: #e8f1fe;
  --ink: #1f2937;
  --muted: #5b6474;
  --line: #e3e8ef;
  --bg: #f7f9fc;
  --card: #ffffff;
  --radius: 16px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0;
  font-family: "Noto Sans JP", "Hiragino Sans", "Yu Gothic UI", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--blue); }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 10;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.site-header .inner {
  max-width: 1080px; margin: 0 auto; padding: 0 16px;
  height: 60px; display: flex; align-items: center; gap: 16px;
}
.brand {
  font-weight: 800; font-size: 1.15rem; color: var(--ink); text-decoration: none;
  display: flex; align-items: center; gap: 8px; white-space: nowrap;
}
.brand-mark {
  width: 28px; height: 28px; border-radius: 7px; background: var(--blue);
  display: grid; place-items: center;
}
.site-nav { display: flex; gap: 4px; margin-left: auto; overflow-x: auto; }

/* Language menu (all pages; generated by tools/langnav.pl) */
.lang-menu { position: relative; flex: none; }
.lang-menu summary {
  list-style: none; cursor: pointer; user-select: none;
  display: flex; align-items: center; gap: 6px; white-space: nowrap;
  color: var(--muted); font-size: .9rem; font-weight: 500;
  padding: 6px 10px; border: 1px solid var(--line); border-radius: 8px; background: var(--card);
}
.lang-menu summary::-webkit-details-marker { display: none; }
.lang-menu summary:hover, .lang-menu[open] summary { background: var(--blue-soft); color: var(--blue-dark); }
.lang-menu ul {
  position: absolute; right: 0; top: calc(100% + 6px); z-index: 20;
  list-style: none; margin: 0; padding: 6px; min-width: 190px;
  background: var(--card); border: 1px solid var(--line); border-radius: 12px;
  box-shadow: 0 10px 30px rgba(0,0,0,.12);
}
.lang-menu li a {
  display: block; padding: 6px 12px; border-radius: 8px;
  color: var(--ink); text-decoration: none; font-size: .92rem;
}
.lang-menu li a:hover { background: var(--blue-soft); }
.lang-menu li a[aria-current="page"] { color: var(--blue-dark); font-weight: 700; }
.footer-langs { display: flex; flex-wrap: wrap; justify-content: center; gap: 4px 0; margin-top: 8px; }

/* Fonts for scripts not covered by Noto Sans JP */
html[lang="ko"] body { font-family: "Noto Sans KR", "Noto Sans JP", sans-serif; }
html[lang="zh-Hans"] body { font-family: "Noto Sans SC", "Noto Sans JP", sans-serif; }
.site-nav a {
  color: var(--muted); text-decoration: none; font-size: .9rem; font-weight: 500;
  padding: 6px 10px; border-radius: 8px; white-space: nowrap;
}
.site-nav a:hover { background: var(--blue-soft); color: var(--blue-dark); }
.site-nav a.lang { border: 1px solid var(--line); }

/* Hero */
.hero { max-width: 1080px; margin: 24px auto 0; padding: 0 16px; }
.hero img { width: 100%; border-radius: var(--radius); box-shadow: 0 8px 30px rgba(26,115,232,.15); }

/* Sections */
main { max-width: 1080px; margin: 0 auto; padding: 0 16px 64px; }
section { margin-top: 64px; }
.eyebrow {
  display: inline-block; font-size: .8rem; font-weight: 700; letter-spacing: .08em;
  color: var(--blue); background: var(--blue-soft); padding: 2px 12px; border-radius: 999px;
}
h2 { font-size: 1.75rem; line-height: 1.4; margin: 12px 0 20px; }
h3 { font-size: 1.15rem; margin: 0 0 6px; }
p { margin: 0 0 1em; }

.lead {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px 32px; font-size: 1.1rem;
}
.lead strong { color: var(--blue-dark); }

/* Features */
.feature-intro {
  background: linear-gradient(135deg, var(--blue), var(--blue-dark));
  color: #fff; border-radius: var(--radius); padding: 28px 32px; font-size: 1.05rem;
}
.feature-intro p:last-child { margin: 0; }
.aruaru-title { margin: 36px 0 16px; font-size: 1.2rem; }
.aruaru {
  list-style: none; padding: 0; margin: 0;
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 12px;
}
.aruaru li {
  background: var(--card); border: 1px solid var(--line); border-radius: 12px;
  padding: 14px 16px 14px 48px; position: relative; line-height: 1.6;
}
.aruaru li::before {
  content: "!"; position: absolute; left: 14px; top: 14px;
  width: 22px; height: 22px; border-radius: 50%;
  background: #fdecea; color: #c5221f; font-weight: 800; font-size: .8rem;
  display: grid; place-items: center;
}
.solve {
  margin-top: 16px; padding: 16px 20px; border-radius: 12px;
  background: var(--blue-soft); color: var(--blue-dark); font-weight: 700;
}

/* Settings */
.settings-group {
  display: grid; grid-template-columns: 260px 1fr; gap: 32px; align-items: start;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 28px; margin-bottom: 24px;
}
.shot { position: sticky; top: 84px; }
.shot img {
  border-radius: 20px; border: 6px solid #1c1c1e; box-shadow: 0 6px 20px rgba(0,0,0,.18);
}
.shot figcaption { font-size: .8rem; color: var(--muted); text-align: center; margin-top: 8px; }
.setting { padding: 18px 0; border-bottom: 1px solid var(--line); }
.setting:first-child { padding-top: 0; }
.setting:last-child { border-bottom: 0; padding-bottom: 0; }
.setting h3::before {
  content: ""; display: inline-block; width: 6px; height: 1em; vertical-align: -2px;
  margin-right: 10px; border-radius: 3px; background: var(--blue);
}
.setting p { color: var(--muted); margin: 0 0 .5em; }
.setting ul { margin: .25em 0 .5em; padding-left: 1.3em; color: var(--muted); }
.setting li { margin: .2em 0; }
.setting li b { color: var(--ink); }
.example {
  background: var(--bg); border: 1px dashed #c7d3e3; border-radius: 10px;
  padding: 10px 14px; font-size: .92rem; color: var(--ink); margin-top: 8px;
}
code {
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  background: var(--blue-soft); color: var(--blue-dark); padding: 1px 6px; border-radius: 5px; font-size: .9em;
}
.default { font-size: .85rem; color: var(--muted); }

/* Footer */
.site-footer {
  border-top: 1px solid var(--line); background: var(--card);
  text-align: center; font-size: .85rem; color: var(--muted); padding: 24px 16px;
}
.site-footer a { margin: 0 8px; }

@media (max-width: 760px) {
  h2 { font-size: 1.4rem; }
  .lead, .feature-intro { padding: 20px; font-size: 1rem; }
  .settings-group { grid-template-columns: 1fr; padding: 20px; gap: 20px; }
  .shot { position: static; max-width: 240px; margin: 0 auto; }
  .site-nav a:not(.lang) { display: none; }
  .aruaru { grid-template-columns: 1fr; }
}

/* Behavior */
.op-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.op-card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px;
}
.op-card h3 { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; }
.op-icon {
  width: 36px; height: 36px; border-radius: 10px; background: var(--blue-soft);
  display: grid; place-items: center; flex: none;
}
.op-card ul { margin: 0; padding-left: 1.2em; color: var(--muted); }
.op-card li { margin: .45em 0; line-height: 1.7; }
.op-card li b { color: var(--ink); }
.op-card h4 { font-size: .95rem; margin: 16px 0 4px; color: var(--ink); }
.note {
  margin-top: 16px; padding: 14px 18px; border-radius: 12px;
  background: #fff8e1; border: 1px solid #f6d77a; color: #6b4e00; font-size: .95rem;
}
.note b { color: #4a3600; }

/* Document page (privacy) */
.doc {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 40px; margin-top: 32px;
}
.doc h1 { font-size: 1.8rem; margin: 0 0 4px; }
.doc .updated { color: var(--muted); font-size: .9rem; margin-bottom: 24px; }
.doc h2 { font-size: 1.15rem; margin: 32px 0 8px; padding-bottom: 6px; border-bottom: 1px solid var(--line); }
.doc ul { padding-left: 1.3em; }
.doc li { margin: .3em 0; }

@media (max-width: 900px) {
  .op-grid { grid-template-columns: 1fr; }
}
@media (max-width: 760px) {
  .doc { padding: 24px 20px; }
  .doc h1 { font-size: 1.4rem; }
}