@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&display=swap');

:root{
  --blue:#3bb1ff;
  --red:#ff5252;
  --ink:#000;
  --paper:#f4f4f2;
  --white:#fff;
  --line:3px solid var(--ink);
  --shadow:5px 5px 0 var(--ink);
  --radius:10px;
  --dock-h:132px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  padding-bottom:var(--dock-h);
  font-family:Inter,"Helvetica Neue",Arial,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  font-size:17px;
  line-height:1.7;
  color:var(--ink);
  background:var(--paper);
  overflow-x:hidden;
}
img{max-width:100%;height:auto;display:block}
a{color:inherit}
h1,h2,h3,h4{font-weight:700;letter-spacing:-.01em}
:focus-visible{outline:3px solid var(--red);outline-offset:3px}
p{margin:0 0 14px}

/* ---------- 底部固定条 ---------- */
.dock{
  position:fixed;
  inset:auto 0 0 0;
  z-index:60;
  display:flex;
  align-items:center;
  gap:10px;
  padding:10px 14px;
  background:var(--white);
  border-top:var(--line);
}
.dock-top{display:contents}
.brand{
  order:0;
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:6px 14px;
  background:var(--blue);
  border:var(--line);
  border-radius:8px;
  box-shadow:4px 4px 0 var(--ink);
  font-size:16px;
  font-weight:600;
  letter-spacing:-.02em;
  text-decoration:none;
  white-space:nowrap;
  transition:transform .12s ease,box-shadow .12s ease;
}
.brand:hover,.brand:focus-visible{transform:translate(2px,2px);box-shadow:2px 2px 0 var(--ink)}
.dock-nav{order:1;flex:1;min-width:0}
.dock-nav>ul{
  list-style:none;
  margin:0;
  padding:0;
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  justify-content:flex-end;
}
.dock-nav>ul>li>a,
.dock-grp summary{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:6px 13px;
  background:var(--white);
  border:var(--line);
  border-radius:8px;
  box-shadow:3px 3px 0 var(--ink);
  font-size:16px;
  font-weight:600;
  text-decoration:none;
  white-space:nowrap;
  cursor:pointer;
  transition:transform .12s ease,box-shadow .12s ease,background .12s ease;
}
.dock-nav>ul>li>a:hover,
.dock-nav>ul>li>a:focus-visible,
.dock-grp summary:hover,
.dock-grp summary:focus-visible,
.dock-grp details[open] summary{
  background:var(--blue);
  transform:translate(2px,2px);
  box-shadow:1px 1px 0 var(--ink);
}
.dock-cta{
  order:2;
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:6px 16px;
  background:var(--red);
  border:var(--line);
  border-radius:8px;
  box-shadow:4px 4px 0 var(--ink);
  font-size:16px;
  font-weight:700;
  text-decoration:none;
  white-space:nowrap;
  transition:transform .12s ease,box-shadow .12s ease;
}
.dock-cta:hover,.dock-cta:focus-visible{transform:translate(2px,2px);box-shadow:2px 2px 0 var(--ink)}

summary{list-style:none}
summary::-webkit-details-marker{display:none}
summary::after{content:"\25BE";margin-left:8px;font-size:11px;line-height:1}
details[open] summary::after{content:"\25B4"}
.dock-grp details{position:static}
.panel{
  position:absolute;
  left:50%;
  bottom:calc(100% + 12px);
  transform:translateX(-50%);
  z-index:70;
  width:min(520px,calc(100vw - 28px));
  padding:10px;
  background:var(--white);
  border:var(--line);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
}
.panel ul{list-style:none;margin:0;padding:0;display:grid;gap:8px}
.panel a{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:6px 12px;
  background:var(--paper);
  border:var(--line);
  border-radius:8px;
  box-shadow:3px 3px 0 var(--ink);
  font-weight:600;
  text-decoration:none;
  transition:transform .12s ease,box-shadow .12s ease,background .12s ease;
}
.panel a:hover,.panel a:focus-visible{background:var(--red);transform:translate(2px,2px);box-shadow:1px 1px 0 var(--ink)}

/* ---------- 英雄区 ---------- */
.masthead{
  position:relative;
  overflow:hidden;
  display:flex;
  align-items:flex-start;
  justify-content:flex-end;
  min-height:45vh;
  padding:36px 20px 28px;
  text-align:right;
  background:var(--white);
  border-bottom:var(--line);
}
.ghost{
  position:absolute;
  right:-10px;
  bottom:-26px;
  z-index:0;
  margin:0;
  white-space:nowrap;
  font-size:clamp(54px,17vw,166px);
  font-weight:700;
  line-height:.9;
  letter-spacing:-.06em;
  color:var(--blue);
  -webkit-text-stroke:2px var(--ink);
  pointer-events:none;
  user-select:none;
}
.masthead-in{position:relative;z-index:1;width:100%;max-width:660px;margin-left:auto}
.masthead h1{margin:0 0 14px;font-size:clamp(30px,6.4vw,54px);line-height:1.1;letter-spacing:-.03em}
.lede{margin:0 0 0 auto;max-width:44ch;font-size:17px;color:#111}
.hero-img{margin-top:22px;width:100%;border:var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}

/* ---------- 正文 ---------- */
main{padding:34px 20px 10px}
div{max-width:740px;margin:0 auto;counter-reset:sec}
div>article{padding:24px 0 30px;border-top:var(--line);scroll-margin-top:16px}
div>article:first-child{border-top:0;padding-top:0}
div>article::before{
  counter-increment:sec;
  content:"0" counter(sec);
  display:block;
  width:max-content;
  margin-bottom:10px;
  padding:2px 10px;
  background:var(--ink);
  color:var(--white);
  border-radius:6px;
  font-size:13px;
  font-weight:600;
  letter-spacing:.16em;
}
div small{
  display:block;
  width:max-content;
  margin-bottom:8px;
  padding:2px 10px;
  background:var(--red);
  border:2px solid var(--ink);
  border-radius:6px;
  font-size:13px;
  font-weight:600;
  letter-spacing:.14em;
}
div h2{margin:0 0 14px;font-size:clamp(21px,3.4vw,29px);line-height:1.25}
div h3{margin:24px 0 10px;font-size:19px;line-height:1.35}
div ul,div ol{margin:0 0 16px;padding-left:24px}
div li{margin:0 0 8px}
div a{
  text-decoration:underline;
  text-decoration-thickness:3px;
  text-decoration-color:var(--blue);
  text-underline-offset:3px;
}
div a:hover{background:var(--blue)}
div blockquote{
  margin:0 0 18px;
  padding:14px 18px;
  background:var(--white);
  border:var(--line);
  border-left-width:8px;
  border-radius:var(--radius);
  box-shadow:4px 4px 0 var(--ink);
}
div blockquote p:last-child{margin:0}
div img{margin:0 0 18px;border:var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
div figure{margin:0 0 18px}
div figure img{margin-bottom:8px}
div figcaption{font-size:15px;color:#333}
div table{width:100%;margin:0 0 18px;border-collapse:collapse;background:var(--white);border:var(--line)}
div th,div td{border:2px solid var(--ink);padding:8px 10px;text-align:left;vertical-align:top}
div th{background:var(--blue)}
div code{background:var(--white);border:2px solid var(--ink);border-radius:4px;padding:0 5px;font-size:.94em}
div hr{border:0;border-top:var(--line);margin:22px 0}

/* ---------- 页脚 ---------- */
footer{margin-top:40px;padding:34px 20px 26px;background:var(--white);border-top:var(--line)}
.foot-grid{display:grid;grid-template-columns:1.25fr 1fr;gap:20px;max-width:860px;margin:0 auto}
footer article{padding:16px;background:var(--paper);border:var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
footer h2{margin:0 0 10px;font-size:20px}
footer small{
  display:block;
  width:max-content;
  margin-bottom:8px;
  padding:2px 10px;
  background:var(--blue);
  border:2px solid var(--ink);
  border-radius:6px;
  font-size:13px;
  font-weight:600;
  letter-spacing:.14em;
}
footer p{margin:0;font-size:16px}
.foot-links ul{list-style:none;margin:0;padding:0;display:grid;gap:8px}
.foot-links a{
  display:flex;
  align-items:center;
  min-height:44px;
  padding:4px 10px;
  background:var(--white);
  border:2px solid var(--ink);
  border-radius:8px;
  font-weight:600;
  text-decoration:none;
  transition:background .12s ease;
}
.foot-links a:hover,.foot-links a:focus-visible{background:var(--red)}
.copy{
  max-width:860px;
  margin:22px auto 0;
  padding-top:14px;
  border-top:var(--line);
  text-align:center;
  font-size:14px;
}

/* ---------- 入场 ---------- */
[data-rev]{opacity:0;transform:translateY(16px);transition:opacity .5s ease,transform .5s ease}
[data-rev].in{opacity:1;transform:none}

@media (max-width:820px){
  :root{--dock-h:152px}
  .dock{flex-wrap:wrap;gap:8px;padding:8px 12px}
  .dock-top{display:flex;width:100%;align-items:center;justify-content:space-between;gap:8px}
  .dock-nav{order:3;flex:0 0 100%;width:100%}
  .dock-nav>ul{justify-content:space-between;gap:6px}
  .dock-nav>ul>li>a,.dock-grp summary{padding:6px 10px}
  .masthead{padding:28px 16px 24px}
  main{padding:26px 16px 8px}
  .foot-grid{grid-template-columns:1fr}
  footer{padding:26px 16px 20px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  [data-rev]{opacity:1;transform:none;transition:none}
  .brand,.dock-cta,.dock-nav a,.panel a,summary{transition:none}
}

button[aria-expanded]{min-width:44px;min-height:44px}