/* invoisapp.com —— 静态站，零构建。样式与 app 的 design tokens 对齐（frontend/src/index.css）。 */
:root {
  --brand: #635bff;
  --brand-dark: #4b45e0;
  --ink: #22304a;
  --ink-soft: #425466;
  --muted: #8792a2;
  --line: #e6e9ef;
  --paper: #f6f8fb;
  --white: #fff;
  --warn-wash: #fff8e6;
  --edge: clamp(1.25rem, 5vw, 3rem);
  --maxw: 720px;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  background: var(--white); color: var(--ink);
  line-height: 1.65; font-size: 16px; -webkit-font-smoothing: antialiased;
}
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }
::selection { background: var(--brand); color: #fff; }
:focus-visible { outline: 2px solid var(--brand); outline-offset: 3px; border-radius: 4px; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 var(--edge); }

header { padding: 28px 0; border-bottom: 1px solid var(--line); }
header .wrap { display: flex; align-items: center; gap: 10px; }
header img { width: 30px; height: 30px; }
header b { font-size: 17px; font-weight: 700; letter-spacing: -0.01em; }

main { padding: 56px 0 72px; }
h1 { font-size: clamp(28px, 6vw, 38px); line-height: 1.2; letter-spacing: -0.02em; font-weight: 800; }
h2 { font-size: 19px; font-weight: 700; margin: 36px 0 10px; letter-spacing: -0.01em; }
h3 { font-size: 16px; font-weight: 700; margin: 22px 0 6px; }
p, li { color: var(--ink-soft); }
p + p { margin-top: 12px; }
ul { margin: 10px 0 0 20px; }
li { margin-bottom: 6px; }
.lede { font-size: 18px; margin-top: 16px; color: var(--ink-soft); }
.meta { font-size: 13.5px; color: var(--muted); margin-top: 8px; }

table { width: 100%; border-collapse: collapse; margin-top: 14px; font-size: 14.5px; display: block; overflow-x: auto; }
th, td { text-align: left; padding: 9px 12px 9px 0; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font-weight: 700; color: var(--ink); white-space: nowrap; }
td { color: var(--ink-soft); }

.note { background: var(--paper); border-radius: 12px; padding: 16px 18px; margin-top: 18px; font-size: 15px; }
.warn { background: var(--warn-wash); }
.note p { color: var(--ink); }

.btn {
  display: inline-block; background: var(--brand); color: #fff;
  padding: 13px 22px; border-radius: 11px; font-weight: 700; font-size: 15px;
  margin-top: 22px; transition: background .15s;
}
.btn:hover { background: var(--brand-dark); text-decoration: none; }

.steps { counter-reset: s; list-style: none; margin-left: 0; }
.steps li { counter-increment: s; position: relative; padding-left: 34px; margin-bottom: 14px; }
.steps li::before {
  content: counter(s); position: absolute; left: 0; top: 1px;
  width: 23px; height: 23px; border-radius: 50%;
  background: var(--brand); color: #fff;
  font-size: 12.5px; font-weight: 700; display: grid; place-items: center;
}

footer { border-top: 1px solid var(--line); padding: 28px 0 44px; font-size: 14px; color: var(--muted); }
footer .wrap { display: flex; flex-wrap: wrap; gap: 8px 20px; align-items: center; }
footer .sp { margin-left: auto; }
@media (max-width: 520px) { footer .sp { margin-left: 0; width: 100%; } }