/* Shared styles for every page. Role colours match the kee-demo: parent green, AI purple, you blue. */
:root {
  --ink: #1c2430; --muted: #4f5a6a; --line: #e3e7ee; --bg: #f6f8fb; --card: #fff;
  --parent: #128c7e; --parent-ink: #0b6b60; --parent-bg: #e8f6f3;
  --ai: #7048c8; --ai-bg: #f1ecfb;
  --you: #2d5bd7; --you-dark: #1f45ad; --you-bg: #eaf0fd;
  --good: #13804b; --warn: #a24a07;
  --radius: 14px;
  --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    "Noto Sans SC", "Segoe UI", Roboto, sans-serif;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; color: var(--ink); background: var(--bg); font: 16px/1.6 var(--font); }
html[data-lang="zh"] .en, html[data-lang="en"] .zh { display: none !important; }
a { color: var(--you); }
:focus-visible { outline: 3px solid #f59e0b; outline-offset: 2px; border-radius: 6px; }
.wrap { max-width: 1040px; margin: 0 auto; padding: 0 20px; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.skip { position: absolute; left: -999px; top: 8px; background: #fff; padding: 12px 16px; z-index: 100; }
.skip:focus { left: 8px; }

/* header */
.top { background: #fff; border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 20; }
.top .wrap { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 60px; }
.logo { font-weight: 700; color: var(--ink); text-decoration: none; display: inline-flex; align-items: center; gap: 8px; min-height: 44px; }
.logo-mark { width: 30px; height: 30px; border-radius: 9px; background: var(--ai); color: #fff; display: inline-grid; place-items: center; font-size: 15px; }
.lang { display: inline-flex; border: 1px solid var(--line); border-radius: 999px; overflow: hidden; flex: none; }
.lang button { border: 0; background: transparent; min-width: 52px; min-height: 44px; padding: 0 14px; font: inherit; font-size: 15px; cursor: pointer; color: var(--muted); }
.lang button[aria-pressed="true"] { background: var(--you); color: #fff; }

/* buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 48px; padding: 12px 22px; border-radius: 12px; font: inherit; font-weight: 600; font-size: 17px; text-decoration: none; cursor: pointer; border: 2px solid transparent; }
.btn-primary { background: var(--you); color: #fff; }
.btn-primary:hover { background: var(--you-dark); }
.btn-secondary { background: #fff; color: var(--you); border-color: var(--you); }
.btn-secondary:hover { background: var(--you-bg); }
.btn-quiet { background: transparent; color: var(--muted); border-color: var(--line); }
.btn[disabled] { opacity: .45; cursor: default; }

/* sections */
section { padding: 44px 0; }
h1 { font-size: clamp(27px, 5vw, 44px); line-height: 1.25; margin: 0 0 14px; letter-spacing: -.01em; }
h2 { font-size: clamp(22px, 3.4vw, 30px); line-height: 1.3; margin: 0 0 8px; }
h3 { font-size: 18px; margin: 0 0 8px; }
.sub { color: var(--muted); margin: 0 0 24px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; }
.grid3 { display: grid; gap: 16px; grid-template-columns: repeat(3, 1fr); }
.grid2 { display: grid; gap: 16px; grid-template-columns: repeat(2, 1fr); }
@media (max-width: 820px) { .grid3, .grid2 { grid-template-columns: 1fr; } }
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 24px; padding: 0; list-style: none; }
.chips li { background: var(--you-bg); color: var(--you-dark); border-radius: 999px; padding: 4px 12px; font-size: 14px; }
.tag { display: inline-block; font-size: 13px; font-weight: 600; padding: 2px 10px; border-radius: 999px; color: #fff; }
.tag.parent { background: var(--parent-ink); } .tag.ai { background: var(--ai); } .tag.you { background: var(--you); }
.quote { font-size: 14px; color: var(--muted); font-style: italic; margin: 10px 0 0; }
.fine { font-size: 14px; color: var(--muted); }

footer.site { padding: 28px 0 40px; color: var(--muted); font-size: 14px; border-top: 1px solid var(--line); background: #fff; }
footer.site nav { display: flex; flex-wrap: wrap; gap: 4px 18px; margin-bottom: 10px; }
footer.site nav a { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; min-width: 44px; }
footer.site p { margin: 4px 0; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}