/* info: stone + leaf, left numeric rail + layered panels */
:root {
  --stone: #5D4037;
  --leaf: #81C784;
  --paper: #EFEBE9;
  --ink: #3E2723;
  --grove: #2E7D32;
  --card: #FFFdf8;
  --line: #d7ccc8;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: "Noto Serif SC", "Songti SC", "SimSun", Georgia, serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.75;
}

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

.top {
  background: var(--stone);
  color: #f3e5d8;
  position: sticky;
  top: 0;
  z-index: 8;
}

.top-inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 14px 20px 16px;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 16px 28px;
}

.brand {
  font-size: 1.15rem;
  letter-spacing: 0.08em;
  font-weight: 700;
  color: #fff;
}

.top-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  font-size: 0.92rem;
}

.top-nav a { color: #f3e5d8; }

.hero {
  max-width: 820px;
  margin: 0 auto;
  padding: 48px 24px 28px;
}

.hero-kicker {
  display: inline-block;
  background: var(--leaf);
  color: var(--ink);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  padding: 4px 10px;
  margin-bottom: 14px;
}

.hero h1 {
  font-size: clamp(1.7rem, 3vw, 2.35rem);
  line-height: 1.35;
  color: var(--stone);
  margin-bottom: 18px;
}

.hero p { margin-bottom: 12px; }

.hero-meta {
  color: #6d4c41;
  font-size: 0.88rem;
}

.stage {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  max-width: 1180px;
  margin: 0 auto 64px;
  padding: 0 16px;
  gap: 8px 20px;
  align-items: start;
}

.rail {
  position: sticky;
  top: 88px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 12px 0;
}

.rail::before {
  content: "";
  position: absolute;
  top: 20px;
  bottom: 20px;
  left: 50%;
  width: 3px;
  background: linear-gradient(var(--leaf), var(--grove));
  transform: translateX(-50%);
  z-index: 0;
}

.rail-dot {
  position: relative;
  z-index: 1;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--grove);
  color: #fff;
  display: grid;
  place-items: center;
  font-family: "Segoe UI", sans-serif;
  font-weight: 700;
  box-shadow: 0 0 0 4px var(--paper);
  text-decoration: none;
}

.rail-dot:hover { background: var(--stone); }

.layers { min-width: 0; }

.layer {
  position: relative;
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 7px solid var(--grove);
  padding: 32px 28px 36px;
  margin-bottom: 22px;
  box-shadow: 10px 10px 0 rgba(129, 199, 132, 0.28);
}

.layer-shift {
  margin-left: 28px;
  border-left-color: var(--stone);
  box-shadow: 10px 10px 0 rgba(93, 64, 55, 0.12);
}

.layer-index {
  position: absolute;
  right: 18px;
  top: 10px;
  font-size: 2.4rem;
  font-weight: 700;
  color: rgba(129, 199, 132, 0.35);
  font-family: "Segoe UI", sans-serif;
  line-height: 1;
}

.layer h2 {
  font-size: 1.45rem;
  color: var(--stone);
  margin-bottom: 14px;
  padding-right: 64px;
}

.layer h3 {
  font-size: 1.05rem;
  color: var(--grove);
  margin-bottom: 6px;
}

.layer p { margin-bottom: 12px; }

.icon-grid {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 18px;
}

.icon-card {
  background: #f4efe8;
  padding: 16px 16px 14px;
  border-top: 3px solid var(--leaf);
}

.icon-card svg { color: var(--grove); margin-bottom: 8px; display: block; }

.split-note {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 8px;
}

.split-note > div {
  background: #f7f1ea;
  padding: 16px;
}

.table-wrap { overflow-x: auto; margin-top: 8px; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
  background: #fff;
}

caption {
  text-align: left;
  font-weight: 700;
  color: var(--stone);
  margin-bottom: 8px;
}

th, td {
  border: 1px solid var(--line);
  padding: 10px 12px;
  text-align: left;
}

th { background: #e8f5e9; color: var(--grove); }

.steps {
  list-style: none;
  margin-top: 16px;
  border-top: 2px dashed var(--leaf);
  padding-top: 8px;
}

.steps li {
  display: grid;
  grid-template-columns: 42px 1fr;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}

.step-n {
  width: 36px;
  height: 36px;
  background: var(--stone);
  color: #fff;
  display: grid;
  place-items: center;
  font-family: "Segoe UI", sans-serif;
  font-weight: 700;
}

.callout {
  display: grid;
  grid-template-columns: 40px 1fr;
  gap: 12px;
  background: #e8f5e9;
  padding: 16px;
  margin-top: 8px;
}

.callout svg { color: var(--grove); }

.faq { margin-top: 10px; }

.faq > div {
  border-bottom: 1px solid var(--line);
  padding: 16px 0;
}

.faq dt {
  font-weight: 700;
  color: var(--stone);
  margin-bottom: 8px;
}

.foot {
  background: var(--ink);
  color: #efebe9;
  padding: 28px 24px 36px;
  text-align: center;
  font-size: 0.9rem;
}

.foot p { margin-bottom: 8px; }

@media (max-width: 800px) {
  .stage { grid-template-columns: 1fr; }
  .rail {
    position: static;
    flex-direction: row;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 12px;
  }
  .rail::before { display: none; }
  .layer-shift { margin-left: 0; }
  .icon-grid, .split-note { grid-template-columns: 1fr; }
}