:root {
  --paper: #f4f1ea;
  --ink: #141413;
  --muted: #5c5a54;
  --line: #d9d4c8;
  --max: 1180px;
  --serif: "Iowan Old Style", "Palatino Linotype", "Songti SC", Georgia, serif;
  --sans: "Avenir Next", "PingFang SC", "Helvetica Neue", sans-serif;
  --mono: "SF Mono", ui-monospace, Menlo, monospace;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
/* hidden 属性必须压倒 form/grid 等作者样式的 display，否则显隐逻辑失效 */
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }
body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
button, .btn { font-family: inherit; cursor: pointer; }
.wrap { width: min(var(--max), calc(100% - 48px)); margin: 0 auto; }
.grain, .noise { display: none; }
header {
  position: sticky; top: 0; z-index: 40;
  background: rgba(244,241,234,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 10px; }
.logo { width: 22px; height: 22px; }
.logo rect, .logo path { stroke: #141413; }
.brand .mark { font-family: var(--sans); font-weight: 650; font-size: 15px; letter-spacing: 0.04em; }
.brand .sub { display: none; }
.nav-links { display: flex; gap: 22px; font-size: 14px; color: var(--muted); }
.nav-links a:hover { color: var(--ink); }
.nav-cta { display: flex; align-items: center; gap: 8px; }
.lang { display: flex; border: 1px solid var(--line); font-family: var(--mono); font-size: 11px; }
.lang button { background: transparent; border: 0; padding: 6px 9px; color: var(--muted); cursor: pointer; }
.lang button.on { background: var(--ink); color: var(--paper); }
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  border: 1px solid var(--ink); background: transparent; color: var(--ink);
  padding: 10px 16px; font-size: 14px; border-radius: 2px;
}
.btn-solid { background: var(--ink); color: var(--paper); }
.hero { padding: 88px 0 64px; }
.hero-grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: 48px; align-items: start; }
.kicker { font-family: var(--mono); font-size: 11px; letter-spacing: .16em; text-transform: uppercase; color: var(--muted); margin-bottom: 16px; }
h1 { font-family: var(--serif); font-weight: 500; font-size: clamp(40px, 6vw, 72px); line-height: 1.02; letter-spacing: -0.03em; }
h1 em { font-style: italic; }
.hero-lead { color: var(--muted); font-size: 18px; max-width: 36ch; margin-top: 22px; }
.hero-actions { margin-top: 28px; display: flex; gap: 10px; flex-wrap: wrap; }
.hero-aside { padding-top: 48px; font-size: 18px; }
.hero-aside ol { padding-left: 18px; }
.hero-aside li { margin: 10px 0; color: var(--muted); }
.hero-aside b { color: var(--ink); }
.hero-meta { margin-top: 56px; display: grid; grid-template-columns: repeat(4,1fr); gap: 24px; border-top: 1px solid var(--line); padding-top: 22px; }
.hero-meta b { display: block; font-size: 15px; margin-bottom: 4px; }
.hero-meta span { color: var(--muted); font-size: 13px; }
.section { padding: 88px 0; }
.section.program { background: var(--ink); color: var(--paper); }
.section.program .lede, .section.program .card p, .section.program .card li, .section.program .week div { color: #c9c4b8; }
.section.program .card, .section.program .layer { background: #1c1c1a; border-color: #2e2d29; }
.section h2 { font-family: var(--serif); font-size: clamp(28px,4vw,48px); font-weight: 500; letter-spacing: -0.03em; margin: 8px 0 16px; line-height: 1.12; }
.lede { color: var(--muted); max-width: 62ch; }
.grid-3, .grid-2 { display: grid; gap: 14px; margin-top: 36px; }
.grid-3 { grid-template-columns: repeat(3,1fr); }
.grid-2 { grid-template-columns: repeat(2,1fr); }
.card { background: #fffdf8; border: 1px solid var(--line); padding: 24px; min-height: 168px; }
.card h3 { font-size: 18px; margin: 8px 0; }
.card p, .card li { color: var(--muted); font-size: 15px; }
.card ol, .card ul { padding-left: 18px; }
.idx { font-family: var(--mono); font-size: 11px; letter-spacing: .12em; color: var(--muted); }
.stack { display: grid; grid-template-columns: 1fr 1fr; gap: 36px; }
.layers { display: flex; flex-direction: column; gap: 10px; }
.layer { border: 1px solid var(--line); background: #fffdf8; padding: 16px 18px; }
.layer span { color: var(--muted); font-size: 14px; }
.weeks { margin-top: 28px; }
.week { display: grid; grid-template-columns: 120px 1fr; gap: 16px; padding: 18px 0; border-bottom: 1px solid #2e2d29; }
.week b { font-family: var(--mono); font-size: 12px; letter-spacing: .12em; }
.industries { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 24px; }
.chip { border: 1px solid var(--line); padding: 8px 12px; font-size: 13px; color: var(--muted); background: #fffdf8; }
table.compare { width: 100%; border-collapse: collapse; margin-top: 28px; font-size: 15px; }
table.compare th, table.compare td { text-align: left; padding: 14px 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
table.compare th { font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); }
form { display: grid; gap: 12px; }
input, select, textarea { width: 100%; background: #fff; border: 1px solid var(--line); color: var(--ink); padding: 12px 14px; font: inherit; }
textarea { min-height: 110px; }
label { font-size: 13px; color: var(--muted); display: grid; gap: 6px; }
label.check { grid-template-columns: auto 1fr; align-items: start; gap: 8px; }
label.check input[type=checkbox] { width: auto; margin: 2px 0 0; }
footer { border-top: 1px solid var(--line); padding: 28px 0 48px; color: var(--muted); font-size: 13px; }
.foot { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; align-items: flex-start; }
.foot-brand { color: var(--ink); letter-spacing: .16em; font-family: var(--serif); font-size: 15px; }
.foot-note { margin-top: 6px; }
.foot-right { display: grid; gap: 6px; justify-items: end; text-align: right; }
.foot-right a:hover { color: var(--ink); }
.foot-legal, .foot-legal a { font-size: 12px; color: var(--muted); }
.foot-legal a:hover { color: var(--ink); }
.price { font-family: var(--serif); font-size: 28px; margin: 8px 0; }
.price small { font-size: 13px; font-family: var(--sans); color: var(--muted); }
.tag { display: inline-block; font-family: var(--mono); font-size: 10px; letter-spacing: .12em; text-transform: uppercase; border: 1px solid var(--line); padding: 3px 8px; }
.catalog { display: grid; gap: 10px; margin-top: 20px; }
.row { display: grid; grid-template-columns: 1fr auto; gap: 16px; align-items: center; border: 1px solid var(--line); padding: 16px 18px; background: #fffdf8; }
.row p { color: var(--muted); font-size: 14px; margin-top: 4px; }
.row .row-head { display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap; }
.row-meta { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 9px; }
.chip { font-family: var(--mono); font-size: 10px; letter-spacing: .08em; border: 1px solid var(--line); color: var(--muted); padding: 2px 7px; white-space: nowrap; }
.chip-risk { border-color: #c9a227; color: #8a6d1b; }
.chip-risk-high { border-color: #b4472f; color: #9a3a25; }
.chip-lock { border-color: #c2bba9; color: #8c8574; background: #f6f3ec; }
.row.locked { background: #fbf9f4; }
.row.locked strong { color: #57534a; }
.group-head { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; margin: 30px 0 12px; padding-bottom: 8px; border-bottom: 1px solid var(--line); }
.group-head:first-child { margin-top: 20px; }
.group-head strong { font-family: var(--serif); font-size: 17px; font-weight: 500; letter-spacing: .01em; }
.group-head span { font-family: var(--mono); font-size: 11px; color: var(--muted); letter-spacing: .1em; }
.lib-note { margin-top: 14px; color: var(--muted); font-size: 13px; }
.plans { display: grid; grid-template-columns: repeat(3,1fr); gap: 12px; margin-top: 28px; }
.plan { border: 1px solid var(--line); padding: 22px; background: #fffdf8; }
.plan.featured { background: var(--ink); color: var(--paper); }
.plan.featured p, .plan.featured li { color: #c9c4b8; }
.plan.featured .btn { border-color: var(--paper); color: var(--paper); }
.plan.featured .btn-solid { background: var(--paper); color: var(--ink); }
.plan ul { margin: 12px 0 18px; padding-left: 18px; color: var(--muted); font-size: 14px; }
.videos { display: grid; grid-template-columns: repeat(3,1fr); gap: 12px; margin-top: 24px; }
.vid { border: 1px solid var(--line); background: #fffdf8; overflow: hidden; }
.vid .thumb { height: 120px; background: #1a1916; color: #d9c38a; display: flex; align-items: flex-end; padding: 12px; font-family: var(--mono); font-size: 11px; letter-spacing: .12em; }
.vid .body { padding: 14px 16px 18px; }
.note-box { margin-top: 18px; color: var(--muted); font-size: 13px; }
.tabs { display: flex; gap: 8px; flex-wrap: wrap; margin: 20px 0; }
.tabs a, #kinds button { border: 1px solid var(--line); padding: 8px 12px; font-size: 13px; color: var(--muted); background: transparent; }
.tabs a.on, #kinds button.on { background: var(--ink); color: var(--paper); }
@media (max-width: 860px) {
  .nav-links { display: none; }
  .nav-cta .btn:not(.btn-solid) { display: none; }
  .hero-grid, .hero-meta, .grid-3, .grid-2, .stack, .week, .plans, .videos, .row { grid-template-columns: 1fr; }
  .hero { padding-top: 48px; }
  h1 { font-size: 40px; }
  .foot-right { justify-items: start; text-align: left; }
}