/* Folio 官网：白 + 黑，书页留一点米色。无外部依赖，只用系统字体。 */

:root {
  --ink: #111111;
  --ink-2: #4a4a4a;
  --ink-3: #8a8a8a;
  --line: #e8e8e8;
  --surface: #f4f4f5;
  --paper: #fbf9f4;
  --gold: #b08d57;
  --max: 1080px;
  --serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", Georgia, "Times New Roman", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: #fff;
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--ink); text-decoration: none; }
a:hover { text-decoration: underline; }

:focus-visible { outline: 2px solid var(--gold); outline-offset: 3px; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* 顶部导航 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 600; }
.brand .mark { width: 28px; height: 28px; border-radius: 7px; display: block; }
.nav ul { display: flex; gap: 26px; list-style: none; margin: 0; padding: 0; }
.nav a { color: var(--ink-2); font-size: 15px; }
.nav a:hover { color: var(--ink); text-decoration: none; }

/* 首屏 */
.hero { padding: 72px 0 40px; }
.hero-grid { display: grid; grid-template-columns: 1.05fr 0.95fr; gap: 48px; align-items: center; }
.eyebrow {
  font-size: 12px; letter-spacing: 0.24em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 18px;
}
h1 {
  font-family: var(--serif);
  font-size: clamp(38px, 5.4vw, 60px);
  line-height: 1.15;
  margin: 0 0 18px;
  font-weight: 500;
}
.lede { font-size: 18px; color: var(--ink-2); margin: 0 0 28px; max-width: 30em; }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  height: 52px; padding: 0 26px; border-radius: 26px;
  font-size: 16px; font-weight: 600; border: 1px solid transparent;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--ink); color: #fff; }
.btn-primary:hover { background: #000; }
.btn-ghost { border-color: var(--line); color: var(--ink); background: #fff; }
.note { font-size: 13px; color: var(--ink-3); margin-top: 14px; }

.phone {
  max-width: 320px;
  margin-inline: auto;
  border-radius: 34px;
  overflow: hidden;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.18), 0 2px 6px rgba(0, 0, 0, 0.08);
  border: 1px solid var(--line);
  background: #fff;
}
.phone img { max-height: 660px; object-fit: cover; object-position: top; }

/* 通用分区 */
section { padding: 72px 0; border-top: 1px solid var(--line); }
section > .wrap > h2 {
  font-family: var(--serif);
  font-size: clamp(26px, 3.4vw, 36px);
  font-weight: 500;
  margin: 0 0 12px;
}
.section-lede { color: var(--ink-2); margin: 0 0 40px; max-width: 46em; }

/* 三步 */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; counter-reset: step; }
.step { border-top: 2px solid var(--ink); padding-top: 18px; }
.step h3 { font-size: 18px; margin: 0 0 8px; }
.step p { color: var(--ink-2); margin: 0; font-size: 15px; }
.step .num {
  font-family: var(--serif); font-size: 13px; color: var(--ink-3); letter-spacing: 0.1em;
}

/* 特性 */
.features { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.feature { background: var(--surface); border-radius: 18px; padding: 26px; }
.feature h3 { font-size: 18px; margin: 0 0 8px; }
.feature p { margin: 0; color: var(--ink-2); font-size: 15px; }

/* 图文交替 */
.showcase { display: grid; grid-template-columns: 1fr 1fr; gap: 44px; align-items: center; margin-top: 40px; }
.showcase:nth-of-type(even) .showcase-text { order: 2; }
.showcase h3 { font-family: var(--serif); font-size: 24px; font-weight: 500; margin: 0 0 10px; }
.showcase p { color: var(--ink-2); margin: 0; }
.shot { border-radius: 14px; overflow: hidden; border: 1px solid var(--line); box-shadow: 0 14px 40px rgba(0, 0, 0, 0.1); }

/* 价格 */

/* FAQ */
.faq { border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); padding: 18px 0; }
.faq summary { cursor: pointer; font-weight: 600; font-size: 17px; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "＋"; float: right; color: var(--ink-3); font-weight: 400; }
.faq details[open] summary::after { content: "－"; }
.faq p { color: var(--ink-2); margin: 10px 0 0; }

/* 正文（协议页） */
.doc { padding: 56px 0 72px; }
.doc h1 { font-size: clamp(30px, 4vw, 42px); margin-bottom: 8px; }
.doc .updated { color: var(--ink-3); font-size: 14px; margin: 0 0 36px; }
.doc h2 {
  font-family: var(--serif); font-weight: 500; font-size: 22px;
  margin: 40px 0 12px; padding-top: 6px;
}
.doc p, .doc li { color: var(--ink-2); }
.doc ul { padding-left: 20px; }
.doc li { margin-bottom: 8px; }
.doc table { width: 100%; border-collapse: collapse; margin: 18px 0; font-size: 15px; }
.doc th, .doc td { text-align: left; border-bottom: 1px solid var(--line); padding: 10px 8px; vertical-align: top; }
.doc th { color: var(--ink); font-weight: 600; }
.callout {
  background: var(--paper); border: 1px solid var(--line); border-radius: 14px;
  padding: 18px 20px; margin: 24px 0;
}
.callout p { margin: 0; color: var(--ink-2); }

/* 联系 */
.contact-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin-top: 32px; }
.contact-card { border: 1px solid var(--line); border-radius: 18px; padding: 24px; }
.contact-card h3 { margin: 0 0 6px; font-size: 17px; }
.contact-card p { margin: 0; color: var(--ink-2); font-size: 15px; }
.contact-card a { text-decoration: underline; }

/* 页脚 */
.site-footer { border-top: 1px solid var(--line); padding: 40px 0; color: var(--ink-3); font-size: 14px; }
.footer-grid { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
.site-footer a { color: var(--ink-2); }
.site-footer ul { list-style: none; display: flex; gap: 20px; margin: 0; padding: 0; flex-wrap: wrap; }

@media (max-width: 860px) {
  .hero { padding: 48px 0 24px; }
  .hero-grid, .showcase, .contact-grid { grid-template-columns: 1fr; gap: 32px; }
  .showcase:nth-of-type(even) .showcase-text { order: 0; }
  .steps, .features { grid-template-columns: 1fr; }
  section { padding: 56px 0; }
  .nav ul { gap: 16px; }
  .nav a { font-size: 14px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}