:root{
  --bg:#080c12;--bg2:#0d141d;
  --line:rgba(255,255,255,.08);--line-strong:rgba(255,255,255,.14);
  --ink:#e9f0f6;--muted:#9aa8b6;--faint:#5d6b7a;
  --teal:#2ee6c5;--teal-soft:rgba(46,230,197,.14);
  --accent:#2ee6c5;--nav-bg:rgba(8,12,18,.6);
  --display:"Bricolage Grotesque",serif;--sans:"Geist",sans-serif;--mono:"Geist Mono",monospace;
  color-scheme:dark;
}
:root[data-theme="light"]{
  --bg:#f7f9fb;--bg2:#eef2f6;
  --line:rgba(12,22,32,.09);--line-strong:rgba(12,22,32,.15);
  --ink:#0e1822;--muted:#4f5d6b;--faint:#8593a1;
  --teal:#12bda0;--teal-soft:rgba(13,150,127,.13);--accent:#0b8169;
  --nav-bg:rgba(247,249,251,.72);
  color-scheme:light;
}
@media (prefers-color-scheme: light){
  :root:not([data-theme="dark"]){
    --bg:#f7f9fb;--bg2:#eef2f6;
    --line:rgba(12,22,32,.09);--line-strong:rgba(12,22,32,.15);
    --ink:#0e1822;--muted:#4f5d6b;--faint:#8593a1;
    --teal:#12bda0;--teal-soft:rgba(13,150,127,.13);--accent:#0b8169;
    --nav-bg:rgba(247,249,251,.72);
    color-scheme:light;
  }
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--ink);font-family:var(--sans);font-weight:300;line-height:1.75;-webkit-font-smoothing:antialiased;transition:background-color .35s ease,color .35s ease}
body::before{content:"";position:fixed;inset:0;z-index:-1;
  background:radial-gradient(700px 460px at 80% -8%,rgba(46,230,197,.08),transparent 60%),var(--bg)}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:760px;margin:0 auto;padding:0 28px}

nav{position:sticky;top:0;z-index:10;backdrop-filter:blur(14px);background:var(--nav-bg);border-bottom:1px solid var(--line);transition:background .35s ease,border-color .35s ease}
.nav-inner{max-width:760px;margin:0 auto;padding:0 28px;display:flex;align-items:center;justify-content:space-between;height:62px}
.brand{display:flex;align-items:center;gap:10px;font-family:var(--display);font-weight:700;font-size:19px;letter-spacing:-.02em;color:var(--ink)}
.brand:hover{text-decoration:none}
.nav-right{display:flex;align-items:center;gap:15px}
.back{font-size:14px;color:var(--muted)}
.back:hover{color:var(--teal);text-decoration:none}
.lang-btn{font-family:var(--mono);font-size:13px;color:var(--muted);border:1px solid var(--line-strong);border-radius:8px;padding:6px 10px;cursor:pointer;background:transparent;transition:all .2s;min-width:38px}
.lang-btn:hover{color:var(--teal);border-color:var(--teal)}

.doc{padding:70px 0 90px}
.doc h1{font-family:var(--display);font-weight:700;font-size:clamp(34px,5vw,48px);letter-spacing:-.03em;line-height:1.05;color:var(--ink)}
.updated{font-family:var(--mono);font-size:12.5px;color:var(--faint);margin-top:14px}
.note{margin-top:26px;padding:14px 18px;border:1px dashed var(--line-strong);border-radius:12px;
  font-size:13.5px;color:var(--faint);font-family:var(--mono);line-height:1.6}
.doc h2{font-family:var(--display);font-weight:600;font-size:22px;letter-spacing:-.02em;color:var(--ink);margin:44px 0 12px}
.doc p{color:var(--muted);font-size:16px;margin-bottom:14px}
.doc ul{color:var(--muted);font-size:16px;margin:0 0 14px 22px}
.doc li{margin-bottom:8px}
.doc strong{color:var(--ink);font-weight:500}
.ph{color:var(--teal);font-family:var(--mono);font-size:.92em}

footer{border-top:1px solid var(--line);padding:34px 0;margin-top:30px}
.foot{max-width:760px;margin:0 auto;padding:0 28px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:16px;
  font-family:var(--mono);font-size:12.5px;color:var(--faint)}
.foot a{color:var(--faint)}
.foot a:hover{color:var(--accent)}

/* —— 主题切换 —— */
.ph{color:var(--accent)}
.back:hover{color:var(--accent)}
.lang-btn:hover,.theme-btn:hover{color:var(--accent);border-color:var(--accent)}
.lang-btn,.theme-btn{transition:all .2s,background-color .35s ease,border-color .35s ease}
.theme-btn{display:inline-flex;align-items:center;justify-content:center;color:var(--muted);border:1px solid var(--line-strong);border-radius:8px;padding:6px 8px;cursor:pointer;background:transparent;line-height:0}
.theme-btn svg{width:15px;height:15px;display:block}
.theme-btn .moon{display:none}
:root[data-theme="light"] .theme-btn .sun{display:none}
:root[data-theme="light"] .theme-btn .moon{display:block}
@media (prefers-color-scheme: light){
  :root:not([data-theme="dark"]) .theme-btn .sun{display:none}
  :root:not([data-theme="dark"]) .theme-btn .moon{display:block}
}