:root { --bg:#fff; --fg:#1b1b1f; --sub:#5b5f66; --line:#e3e5e8; --card:#f6f7f9; --on:#fff; }
@media (prefers-color-scheme: dark) { :root { --bg:#16171a; --fg:#ececf0; --sub:#a3a7ae; --line:#2f3136; --card:#212327; } }
* { box-sizing:border-box; }
html { -webkit-text-size-adjust:100%; }
body { margin:0; font:16px/1.7 system-ui,-apple-system,"Segoe UI","Yu Gothic UI","Hiragino Sans","Noto Sans JP","PingFang SC","Microsoft YaHei","Malgun Gothic",sans-serif; background:var(--bg); color:var(--fg); }
/* 言語の切り替え: 選ばれた言語のスパンだけ表示 */
[data-l] { display:none; }
html[data-lang="en"] [data-l="en"], html[data-lang="ja"] [data-l="ja"], html[data-lang="zh"] [data-l="zh"], html[data-lang="ko"] [data-l="ko"] { display:inline; }
.skip { position:absolute; left:-999px; top:0; background:var(--acc); color:var(--on); padding:8px 14px; z-index:10; }
.skip:focus { left:8px; top:8px; }
.top { display:flex; align-items:center; justify-content:space-between; gap:12px; flex-wrap:wrap; max-width:960px; margin:0 auto; padding:14px 20px; }
.brand { display:flex; align-items:center; gap:10px; font-weight:700; color:var(--fg); text-decoration:none; }
.brand img { border-radius:7px; }
.langs { display:flex; gap:4px; flex-wrap:wrap; }
.langs button { font:inherit; font-size:13px; padding:4px 11px; border-radius:99px; border:1px solid var(--line); background:transparent; color:var(--sub); cursor:pointer; }
.langs button[aria-pressed="true"] { background:var(--acc); border-color:var(--acc); color:var(--on); }
main { max-width:960px; margin:0 auto; padding:0 20px 56px; }
section { margin-top:44px; }
h2 { font-size:13px; letter-spacing:.06em; text-transform:uppercase; color:var(--sub); margin:0 0 14px; }
.hero { text-align:center; padding:28px 0 8px; margin-top:0; }
.hero .icon { border-radius:28px; box-shadow:0 10px 36px rgba(0,0,0,.18); }
.hero .kind { margin:18px 0 0; color:var(--acc); font-weight:700; font-size:14px; }
.hero h1 { margin:2px 0 6px; font-size:clamp(34px,7vw,56px); line-height:1.1; letter-spacing:-.02em; }
.hero .tag { margin:0 auto; max-width:30ch; font-size:clamp(20px,3.6vw,28px); line-height:1.4; color:var(--fg); font-weight:600; }
.cards { list-style:none; margin:0; padding:0; display:grid; grid-template-columns:repeat(auto-fit,minmax(250px,1fr)); gap:14px; }
.cards li { background:var(--card); border:1px solid var(--line); border-radius:18px; padding:20px 20px 18px; }
.cards .n { display:inline-grid; place-items:center; width:30px; height:30px; border-radius:50%; background:var(--acc); color:var(--on); font-weight:700; font-size:14px; }
.cards p { margin:12px 0 0; }
.how { background:var(--acc); color:var(--on); border-radius:22px; padding:26px 28px; }
.how h2 { color:rgba(255,255,255,.78); }
.how .big { margin:0; font-size:clamp(19px,3vw,24px); line-height:1.5; font-weight:600; }
.priv p { margin:0 0 8px; } .priv { border:1px solid var(--line); border-radius:18px; padding:20px 22px; }
.small { color:var(--sub); font-size:14px; }
.apps { list-style:none; margin:0; padding:0; display:grid; grid-template-columns:repeat(auto-fill,minmax(250px,1fr)); gap:10px; }
.apps a { display:flex; gap:12px; align-items:center; padding:12px 14px; border:1px solid var(--line); border-radius:16px; color:var(--fg); text-decoration:none; background:var(--card); }
.apps a:hover, .apps a:focus-visible { border-color:var(--acc); }
.apps img { border-radius:10px; flex:none; }
.apps b { display:block; } .apps small { display:block; color:var(--sub); line-height:1.4; font-size:13px; }
a:focus-visible, button:focus-visible { outline:3px solid var(--acc); outline-offset:2px; }
@media (max-width:520px) { .top, main { padding-left:16px; padding-right:16px; } .how { padding:22px 20px; } }
@media (prefers-reduced-motion: no-preference) { .apps a { transition:border-color .15s; } }