/* bindchat support site — white / black / a touch of sky blue */
:root {
  --ink: #111111;
  --sub: #5f6368;
  --line: #e6e8eb;
  --accent: #0ea5e9;
  --accent-soft: #e0f4fd;
  --bg: #ffffff;
  --card: #f7f9fb;
  color-scheme: light;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.75;
}
a { color: var(--accent); text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
.wrap { max-width: 720px; margin: 0 auto; padding: 0 20px; }

header.site {
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; background: rgba(255,255,255,.92);
  backdrop-filter: saturate(180%) blur(12px); -webkit-backdrop-filter: saturate(180%) blur(12px);
  z-index: 10;
}
header.site .wrap { display: flex; align-items: center; gap: 12px; height: 56px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font-weight: 700; letter-spacing: .01em; }
.brand img { width: 30px; height: 30px; border-radius: 7px; border: 1px solid var(--line); }
nav.links { margin-left: auto; display: flex; gap: 16px; font-size: 14px; align-items: center; }
nav.links a { color: var(--ink); text-decoration: none; white-space: nowrap; }
@media (max-width: 400px) { nav.links { gap: 10px; font-size: 13px; } .brand { font-size: 15px; } }
nav.links a[aria-current="page"] { color: var(--accent); font-weight: 600; }
nav.links .lang { border: 1px solid var(--line); border-radius: 999px; padding: 2px 10px; }

.hero { text-align: center; padding: 48px 0 24px; }
.hero img.icon { width: 112px; height: 112px; border-radius: 25px; border: 1px solid var(--line); box-shadow: 0 8px 24px rgba(14,165,233,.15); }
.hero h1 { font-size: 32px; margin: 16px 0 4px; letter-spacing: .01em; }
.hero p.tag { color: var(--sub); margin: 0 auto; max-width: 520px; }
.dot { color: var(--accent); }

main { padding-bottom: 48px; }
h2 { font-size: 21px; margin: 40px 0 8px; padding-bottom: 6px; border-bottom: 2px solid var(--accent-soft); }
h3 { font-size: 17px; margin: 24px 0 4px; }
p, ul, ol { margin: 8px 0; }
ul, ol { padding-left: 1.4em; }
li { margin: 4px 0; }
.sub { color: var(--sub); font-size: 14px; }

.features { display: grid; grid-template-columns: 1fr; gap: 12px; margin: 16px 0; padding: 0; list-style: none; }
@media (min-width: 600px) { .features { grid-template-columns: 1fr 1fr; } }
.features li { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 14px 16px; margin: 0; }
.features strong { display: block; margin-bottom: 2px; }

details { border: 1px solid var(--line); border-radius: 12px; padding: 0 16px; margin: 10px 0; background: #fff; }
details[open] { background: var(--card); }
summary { cursor: pointer; font-weight: 600; padding: 12px 0; list-style: none; position: relative; padding-right: 24px; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; position: absolute; right: 0; top: 10px; color: var(--accent); font-size: 20px; font-weight: 400; }
details[open] summary::after { content: "–"; }
details > :last-child { margin-bottom: 14px; }

.note { background: var(--accent-soft); border-radius: 12px; padding: 12px 16px; margin: 16px 0; }
.contact { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 16px; }
.mail { font-weight: 600; word-break: break-all; }
table { border-collapse: collapse; width: 100%; font-size: 14px; margin: 8px 0; }
th, td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; vertical-align: top; }
th { background: var(--card); }

footer.site { border-top: 1px solid var(--line); padding: 20px 0 32px; color: var(--sub); font-size: 13px; }
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 8px 16px; }
footer.site a { color: var(--sub); }