html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans CJK SC",sans-serif}
.hero-bg{background:radial-gradient(ellipse at top left,#e0e7ff 0,transparent 55%),radial-gradient(ellipse at bottom right,#fae8ff 0,transparent 50%),#f8fafc}
details>summary{list-style:none;cursor:pointer}
details>summary::-webkit-details-marker{display:none}
details[open] .chev{transform:rotate(45deg)}
.plan-opt input:checked + div{border-color:#4f46e5;box-shadow:0 0 0 2px #c7d2fe;background:#eef2ff}
.pay-opt input:checked + div{border-color:#4f46e5;background:#eef2ff}