/*
 * [INPUT]: index.html 品牌/产品及静态信任页的内容和导航。
 * [OUTPUT]: 移动优先首页/信任页、44px 链接、可见焦点与窄屏邮件地址换行。
 * [POS]: public 的独立视觉层，不加载 src 工具样式、外部字体或图片。
 * [PROTOCOL]: 变更时更新此头部，然后检查 CLAUDE.md
 */
:root { font-family: system-ui, sans-serif; color: #143d32; background: #f5f4ed; line-height: 1.6; font-synthesis: none; }
* { box-sizing: border-box; }
body { margin: 0; }
header, main, footer { width: min(100% - 40px, 1080px); margin-inline: auto; }
header { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding-block: 16px; }
a { color: inherit; text-underline-offset: 4px; touch-action: manipulation; }
a:focus-visible, main:focus-visible { outline: 3px solid #577500; outline-offset: 4px; }
.brand { display: inline-flex; align-items: center; min-height: 44px; font-size: 20px; font-weight: 850; letter-spacing: -.8px; text-decoration: none; }
.brand-dot { color: #577500; }
.preview { font-size: 11px; color: #4c645b; text-align: right; min-width: 0; overflow-wrap: anywhere; }
.skip-link { position: absolute; top: 8px; left: 8px; z-index: 1; padding: 10px 16px; background: #fffef8; transform: translateY(-150%); }
.skip-link:focus { transform: none; }
.hero { padding-block: 24px 32px; }
.eyebrow { font-size: 11px; font-weight: 750; letter-spacing: 1.8px; margin: 0 0 14px; }
h1 { font-size: clamp(38px, 6vw, 68px); font-weight: 850; letter-spacing: -1.8px; line-height: 1.06; margin: 0 0 20px; }
h1 em { font-style: normal; background: #d5ed79; border-radius: 6px; padding-inline: 4px; }
.lead { color: #4c645b; font-size: 16px; margin: 0; max-width: 40ch; }
.puzzle-art { display: none; }
.product { padding: 24px; border: 1px solid #cdd7c6; border-radius: 20px; background: #fffef8; box-shadow: 0 12px 36px #143d3208; }
.tag { display: inline-block; border: 1px solid #d3dec4; border-radius: 20px; background: #edf3e4; font-size: 10px; font-weight: 700; letter-spacing: .5px; padding: 4px 9px; margin: 0 0 12px; }
h2 { font-size: 28px; letter-spacing: -.8px; line-height: 1.2; margin: 0 0 12px; }
.product-copy { font-size: 15px; color: #4c645b; margin: 0 0 20px; }
.mini { display: none; }
.primary { display: inline-flex; align-items: center; justify-content: space-between; gap: 16px; min-height: 48px; max-width: 100%; padding: 12px 16px; background: #d5ed79; border: 1px solid #b5ce5b; border-radius: 8px; font-size: 14px; font-weight: 750; text-decoration: none; overflow-wrap: anywhere; }
.primary:hover { background: #c9e668; }
.trust { display: flex; flex-wrap: wrap; gap: 6px 16px; list-style: none; padding: 0; margin: 20px 0 0; font-size: 12px; color: #4c645b; }
.trust li::before { content: '·'; margin-right: 6px; color: #577500; font-weight: 800; }
.about { max-width: 660px; border-left: 3px solid #d5ed79; padding-left: 20px; margin-block: 40px; }
.about h2 { font-size: 22px; }
.about p { color: #4c645b; font-size: 15px; margin: 0; }
footer { border-top: 1px solid #d2d8cd; padding-block: 16px 24px; color: #4c645b; }
footer nav { display: flex; flex-wrap: wrap; gap: 8px 24px; }
footer a { display: inline-flex; align-items: center; min-height: 44px; font-size: 13px; }
footer p { margin: 8px 0 0; font-size: 12px; }
.document { max-width: 720px; margin-block: 32px 56px; overflow-wrap: anywhere; }
.document h1 { font-size: clamp(32px,5vw,48px); letter-spacing: -1px; }
.document h2 { font-size: 22px; }
.document section { padding-block: 24px; border-bottom: 1px solid #d2d8cd; }
.document p, .document li { color: #4c645b; font-size: 15px; }
.document .updated { font-size: 12px; }
@media (min-width: 760px) {
  header { padding-block: 24px; }
  .hero { display: grid; grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr); gap: 32px; align-items: center; padding-block: 48px 56px; }
  .puzzle-art { display: grid; grid-template-columns: repeat(5, 44px); gap: 6px; justify-self: center; transform: rotate(-7deg); }
  .puzzle-art span { display: grid; place-items: center; height: 44px; background: #fffef8; border: 1px solid #c8d2c0; border-radius: 9px; box-shadow: 0 3px 0 #d9e0d0; font-size: 21px; font-weight: 650; }
  .puzzle-art .operator { background: #e8eddf; color: #4c645b; box-shadow: none; }
  .puzzle-art .answer { background: #d5ed79; }
  .puzzle-art .unused { background: none; border: none; box-shadow: none; }
  .product { max-width: 820px; padding: 32px; }
  .mini { float: right; display: grid; grid-template-columns: repeat(3, 40px); gap: 5px; margin: 16px 0 12px 24px; transform: rotate(5deg); }
  .mini span { display: grid; place-items: center; height: 40px; border-radius: 8px; background: #e8eddf; font-size: 20px; font-weight: 650; }
  .mini .answer { background: #d5ed79; }
  .about { margin-block: 48px 56px; }
}
@media (max-width: 380px) {
  header, main, footer { width: calc(100% - 32px); }
  header { padding-block: 10px; }
  .hero { padding-block: 20px 28px; }
  .product { padding: 20px; }
  .primary { gap: 8px; padding-inline: 12px; }
}