/* ==== px-shell:start（规范见 sites/DESIGN.md；pages / download / account 三处必须逐字一致，由 sites/pages/tests 校验）==== */
:root {
  --cream: #fbf8ed;
  --cream-2: #f1ecdc;
  --ink: #181915;
  --muted: #6d6a60;
  --brick: #ae4b3f;
  --line: rgba(24, 25, 21, 0.18);
  --surface: rgba(255, 255, 255, 0.58);
  --on-brick: #fff;
  --px-header-bg: rgba(251, 248, 237, 0.92);
  --px-active-bg: rgba(174, 75, 63, 0.1);
  --font-body: "MiSans", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --radius-sm: 14px;
  --radius-md: 24px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --cream: #181915;
    --cream-2: #22231e;
    --ink: #fbf8ed;
    --muted: #a8a596;
    --brick: #e07a6c;
    --line: rgba(251, 248, 237, 0.2);
    --surface: rgba(255, 255, 255, 0.05);
    --on-brick: #181915;
    --px-header-bg: rgba(24, 25, 21, 0.92);
    --px-active-bg: rgba(224, 122, 108, 0.16);
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--cream); color: var(--ink); font: 16px/1.6 var(--font-body); }
a { color: var(--brick); }
[hidden] { display: none !important; }
:focus-visible { outline: 3px solid var(--brick); outline-offset: 2px; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.px-skip { position: absolute; left: 12px; top: -64px; z-index: 100; padding: 8px 14px; background: var(--ink); color: var(--cream); border-radius: 8px; text-decoration: none; }
.px-skip:focus { top: 12px; }

.px-header { position: sticky; top: 0; z-index: 50; background: var(--px-header-bg); -webkit-backdrop-filter: blur(10px); backdrop-filter: blur(10px); border-bottom: 1px solid var(--line); }
.px-header-in { position: relative; max-width: var(--px-max, 920px); margin: 0 auto; padding: 8px 16px; display: flex; align-items: center; gap: 12px; min-height: 56px; }
.px-brand { display: inline-flex; align-items: center; gap: 8px; font-weight: 800; letter-spacing: 0.04em; color: var(--ink); text-decoration: none; white-space: nowrap; }
.px-brand img { width: 28px; height: 28px; border-radius: 7px; display: block; }
.px-nav { display: flex; align-items: center; gap: 2px; margin-left: auto; }
.px-nav a { padding: 8px 12px; border-radius: 999px; color: var(--muted); text-decoration: none; font-weight: 600; font-size: 0.95rem; white-space: nowrap; }
.px-nav a:hover { color: var(--ink); }
.px-nav a[aria-current="page"] { color: var(--brick); background: var(--px-active-bg); }
.px-lang select { font: inherit; font-size: 0.9rem; background: var(--surface); color: var(--ink); border: 1px solid var(--line); border-radius: 999px; padding: 6px 12px; min-height: 36px; }
.px-menu-btn { display: none; font: inherit; font-size: 0.9rem; font-weight: 600; background: var(--surface); color: var(--ink); border: 1px solid var(--line); border-radius: 999px; padding: 6px 14px; min-height: 36px; cursor: pointer; }
@media (max-width: 760px) {
  .px-menu-btn { display: inline-flex; align-items: center; }
  .px-lang { margin-left: auto; }
  .px-nav { display: none; position: absolute; top: 100%; left: 0; right: 0; margin: 0; flex-direction: column; align-items: stretch; gap: 0; padding: 8px 16px 14px; background: var(--cream); border-bottom: 1px solid var(--line); box-shadow: 0 14px 28px rgba(0, 0, 0, 0.12); }
  .px-header[data-open] .px-nav { display: flex; }
  .px-nav a { padding: 12px 8px; border-radius: 10px; font-size: 1rem; }
}

.px-footer { border-top: 1px solid var(--line); margin-top: 56px; padding: 28px 0 40px; color: var(--muted); font-size: 0.9rem; }
.px-footer-in { max-width: var(--px-max, 920px); margin: 0 auto; padding: 0 16px; display: flex; flex-wrap: wrap; gap: 20px 48px; justify-content: space-between; }
.px-footer-brand { max-width: 34em; }
.px-footer-brand strong { color: var(--ink); letter-spacing: 0.04em; }
.px-footer-brand p { margin: 6px 0 0; }
.px-footer-links { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 4px 20px; align-content: flex-start; }
.px-footer-links a { color: var(--muted); display: inline-block; padding: 6px 0; }
.px-footer-links a:hover, .px-footer-links a[aria-current="page"] { color: var(--brick); }
/* ==== px-shell:end ==== */

/* 静态内容页（使用说明 / 隐私政策 / 用户协议 / 404）专用样式。 */
html:not([lang="en"]) [data-l="en"], html[lang="en"] [data-l="zh"] { display: none !important; }
.px-main { max-width: var(--px-max, 920px); margin: 0 auto; padding: 8px 16px 0; min-height: 60vh; }
.px-main h1 { font-size: clamp(2rem, 6vw, 2.8rem); line-height: 1.15; margin: 32px 0 8px; }
.px-main h2 { font-size: 1.35rem; margin: 40px 0 10px; scroll-margin-top: 72px; }
.px-main h3 { font-size: 1.05rem; margin: 24px 0 6px; }
.px-main p, .px-main li { max-width: 46em; }
.px-main ul, .px-main ol { padding-left: 1.4em; }
.px-main li { margin: 4px 0; }
.lead { color: var(--muted); font-size: 1.08rem; }
.meta { color: var(--muted); font-size: 0.9rem; }
.callout { background: var(--surface); border: 1px solid var(--line); border-left: 4px solid var(--brick); border-radius: var(--radius-sm); padding: 12px 16px; margin: 16px 0; }
.callout strong:first-child { color: var(--brick); }
.toc { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 12px 20px; margin: 20px 0; }
.toc ol { margin: 4px 0; columns: 2 220px; }
.toc a { text-decoration: none; }
.px-main code { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 0.86em; background: var(--cream-2); padding: 1px 6px; border-radius: 6px; word-break: break-all; }
.px-main table { border-collapse: collapse; width: 100%; margin: 12px 0; font-size: 0.95rem; }
.px-main th, .px-main td { text-align: left; vertical-align: top; padding: 8px 10px; border-top: 1px solid var(--line); }
.px-main th { color: var(--muted); font-weight: 600; }
.table-wrap { overflow-x: auto; }
details.faq { border-top: 1px solid var(--line); padding: 10px 0; }
details.faq:last-of-type { border-bottom: 1px solid var(--line); }
details.faq summary { cursor: pointer; font-weight: 600; }
details.faq p { margin: 8px 0 0; }
.px-btn { display: inline-block; border: 1px solid var(--line); background: var(--surface); color: var(--ink); border-radius: 999px; padding: 10px 22px; text-decoration: none; font-weight: 600; min-height: 44px; }
.px-btn:hover { border-color: var(--brick); }
.px-btn-primary { background: var(--brick); border-color: var(--brick); color: var(--on-brick); }
.actions { display: flex; flex-wrap: wrap; gap: 10px; margin: 20px 0; }