:root {
  --bg: #f7fafc;
  --card: #ffffff;
  --accent: #0e7490;
  --highlight: #15803d;
  --warn: #b45309;
  --danger: #dc2626;
  --text: #0f172a;
  --text-dim: #475569;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--text);
  font-family: "Segoe UI", "Microsoft YaHei", "PingFang SC", "Noto Sans SC", sans-serif; }

#hero { position: relative; min-height: 88vh; display: flex; align-items: center; justify-content: center; overflow: hidden; }
.hero-peaks { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; opacity: 0.85; pointer-events: none; }
.hero-inner { position: relative; text-align: center; padding: 2rem 1.5rem; max-width: 46rem; }
.hero-inner h1 { font-size: clamp(1.8rem, 5vw, 3.2rem); margin: 0 0 0.5rem; }
.hero-sub { color: var(--accent); letter-spacing: 0.08em; margin: 0 0 1.5rem; }
.hero-tagline { color: var(--text-dim); line-height: 1.9; margin: 0 auto 2rem; max-width: 38rem; }
.hero-cta { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }
.btn { display: inline-block; padding: 0.7rem 1.6rem; border: 1px solid var(--accent); border-radius: 6px; color: var(--accent); text-decoration: none; }
.btn-primary { background: var(--accent); color: #ffffff; font-weight: 600; }

/* ===== 顶栏（品牌 + 移动端汉堡） ===== */
.topbar { position: sticky; top: 0; z-index: 10; display: flex; align-items: center; justify-content: space-between;
  padding: 0.75rem 1.5rem; background: rgba(247, 250, 252, 0.92); backdrop-filter: blur(6px); border-bottom: 1px solid rgba(15, 23, 42, 0.08); }
.brand { color: var(--text); font-weight: 700; white-space: nowrap; }
.nav-toggle { display: none; background: none; border: 1px solid rgba(15, 23, 42, 0.15); color: var(--text); font-size: 1.2rem; border-radius: 4px; padding: 0.2rem 0.6rem; }

/* ===== 右侧竖向导航（随滚动固定于右侧垂直居中） ===== */
.nav-links { position: fixed; z-index: 10; right: 1rem; top: 50%; transform: translateY(-50%);
  list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 0.45rem; }
.nav-links a { display: block; padding: 0.35rem 0.9rem; border-radius: 999px; border: 1px solid rgba(15, 23, 42, 0.1);
  background: var(--card); color: var(--text-dim); text-decoration: none; font-size: 0.85rem;
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.06); white-space: nowrap; }
.nav-links a:hover, .nav-links a.active { color: #ffffff; background: var(--accent); border-color: var(--accent); }

/* ===== 版块通用 ===== */
.section { padding: 5rem 1.5rem; max-width: 68rem; margin: 0 auto; }
main section[id] { scroll-margin-top: 4.5rem; }
.section-title { font-size: clamp(1.5rem, 3vw, 2.1rem); text-align: center; margin: 0 0 0.6rem; }
.section-sub { color: var(--text-dim); text-align: center; max-width: 42rem; margin: 0 auto 3rem; line-height: 1.8; }
.section-divider { display: block; margin: 4rem auto 0; width: min(80%, 30rem); height: 2.5rem; color: var(--accent); opacity: 0.6; }

/* ===== 卡片 ===== */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr)); gap: 1.2rem; }
.card { background: var(--card); border: 1px solid rgba(15, 23, 42, 0.08); border-radius: 10px; padding: 1.4rem;
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.05); }
.card h3 { margin: 0 0 0.5rem; color: var(--accent); font-size: 1.05rem; }
.card p { margin: 0; color: var(--text-dim); line-height: 1.8; font-size: 0.95rem; }

/* ===== 数字条 ===== */
.stat-strip { display: flex; flex-wrap: wrap; gap: 1rem 2.5rem; justify-content: center; margin-bottom: 2.5rem; }
.stat { text-align: center; }
.stat b { display: block; font-size: 1.6rem; color: var(--highlight); font-variant-numeric: tabular-nums; }
.stat span { color: var(--text-dim); font-size: 0.85rem; }

/* ===== 流程图 ===== */
.flow-steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(9rem, 1fr)); gap: 0.8rem; counter-reset: step; margin-bottom: 2rem; }
.flow-step { background: var(--card); border: 1px solid rgba(15, 23, 42, 0.08); border-radius: 8px; padding: 0.9rem 0.7rem;
  text-align: center; font-size: 0.9rem; color: var(--text-dim); position: relative; }
.flow-step::before { counter-increment: step; content: counter(step); display: block; color: var(--accent); font-weight: 700; margin-bottom: 0.3rem; }

/* ===== 流程角标 ===== */
.step-badge { position: absolute; top: 0.4rem; right: 0.5rem; font-size: 0.68rem; color: var(--highlight);
  border: 1px solid rgba(21, 128, 61, 0.5); border-radius: 999px; padding: 0.05rem 0.45rem; white-space: nowrap; }

/* ===== 链标题/说明 + 人的角色横幅 ===== */
.chain-title { text-align: center; margin: 2.5rem 0 0.4rem; }
.chain-note { color: var(--text-dim); text-align: center; font-size: 0.92rem; margin: 0 auto 1.4rem; }
.human-role { max-width: 42rem; margin: 2.5rem auto 1.2rem; padding: 0.9rem 1.4rem; text-align: center;
  background: rgba(14, 116, 144, 0.07); border: 1px solid rgba(14, 116, 144, 0.3); border-radius: 8px; }

/* ===== 截图 ===== */
.figure-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(18rem, 1fr)); gap: 1.5rem; }
.figure-grid figure { margin: 0; background: var(--card); border-radius: 10px; padding: 0.8rem;
  border: 1px solid rgba(15, 23, 42, 0.08); box-shadow: 0 1px 3px rgba(15, 23, 42, 0.05); }
.figure-grid img { width: 100%; display: block; border-radius: 6px; transition: transform 0.25s ease; }
.figure-grid figure:hover img { transform: scale(1.03); }
.figure-grid figcaption { color: var(--text-dim); font-size: 0.88rem; padding: 0.7rem 0.3rem 0.2rem; line-height: 1.7; }

/* ===== 报告卡片 ===== */
.report-card { background: var(--card); border: 1px solid rgba(14, 116, 144, 0.35); border-radius: 10px; padding: 1.8rem; max-width: 46rem; margin: 0 auto; }
.report-card h3 { color: var(--accent); margin-top: 0; }
.report-card table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
.report-card th, .report-card td { border: 1px solid rgba(15, 23, 42, 0.12); padding: 0.45rem 0.6rem; text-align: left; }
.report-card th { color: var(--text); }
.report-card td { color: var(--text-dim); }
.tag-ok { color: var(--highlight); }
.tag-warn { color: var(--warn); }
.tag-bad { color: var(--danger); }

/* ===== 代码块 ===== */
.code-block { position: relative; background: var(--card); border: 1px solid rgba(15, 23, 42, 0.08); border-radius: 8px;
  padding: 1rem 3.2rem 1rem 1.2rem; overflow-x: auto; }
.code-block code { font-family: Consolas, "Courier New", monospace; color: var(--highlight); font-size: 0.92rem; overflow-wrap: anywhere; white-space: pre-wrap; }
.copy-btn { position: absolute; top: 0.5rem; right: 0.5rem; background: none; border: 1px solid var(--accent); color: var(--accent); border-radius: 4px; padding: 0.2rem 0.6rem; font-size: 0.8rem; cursor: pointer; }
.copy-btn:hover { background: var(--accent); color: #ffffff; }

/* ===== FAQ ===== */
.faq-item { background: var(--card); border-radius: 8px; margin-bottom: 0.8rem; border: 1px solid rgba(15, 23, 42, 0.08); }
.faq-item summary { padding: 1rem 1.2rem; cursor: pointer; color: var(--text); font-weight: 600; list-style-position: inside; }
.faq-item summary:hover { color: var(--accent); }
.faq-item p { margin: 0; padding: 0 1.2rem 1.1rem; color: var(--text-dim); line-height: 1.8; }

/* ===== 视频按钮 ===== */
#video-demo-btn[hidden] { display: none; }

/* ===== 页脚 ===== */
.site-footer { border-top: 1px solid rgba(15, 23, 42, 0.08); padding: 2.5rem 1.5rem; text-align: center; color: var(--text-dim); font-size: 0.9rem; line-height: 2; }
.site-footer a { color: var(--accent); text-decoration: none; }

/* ===== 滚动淡入（仅 JS 生效时隐藏初始态；无 JS/JS 失败时内容直接可见）===== */
.js .fade-in { opacity: 0; transform: translateY(14px); transition: opacity 0.55s ease, transform 0.55s ease; }
.js .fade-in.visible { opacity: 1; transform: none; }

/* ===== 响应式（移动端：导航改为顶栏下方下拉面板） ===== */
@media (max-width: 48rem) {
  .nav-toggle { display: block; }
  .nav-links { display: none; top: 3.4rem; right: 1rem; transform: none;
    background: var(--bg); border: 1px solid rgba(15, 23, 42, 0.08); border-radius: 8px; padding: 0.5rem; }
  .nav-links.open { display: flex; }
  .section { padding: 3.5rem 1.2rem; }
}

/* ===== 动效偏好 ===== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .fade-in { opacity: 1; transform: none; transition: none; }
  .figure-grid img { transition: none; }
}