/* Kairn 官网 · 纸石
   和 App 同一套材质：实色纸面、1px 暖色细线、带墨色的柔和投影、
   主按钮是上亮下暗的石头。没有毛玻璃，没有高光。 */

:root {
  --canvas: #f6f2ea;
  --paper: #fffefb;
  --paper-2: #fbf8f2;
  --sand: #ede6da;
  --ink: #18202c;
  --ink-2: #3c4552;
  --slate: #6f746f;
  --faint: #9a9a92;
  --line: #d8d0c3;
  --line-soft: rgba(216, 208, 195, 0.62);
  --stone: #2f4858;
  --stone-hi: #3a5669;
  --stone-lo: #22394a;
  --amber: #cc8438;
  --amber-hi: #f1b86e;
  --amber-soft: rgba(241, 184, 110, 0.26);
  --sage: #62756c;
  --shade: 34, 57, 74;
  --cloth-1: #3e5a6e; --cloth-2: #5d8a76; --cloth-3: #b06e58;
  --cloth-4: #c49248; --cloth-5: #6c5a80; --cloth-6: #4a7c80;
  --serif: "Songti SC", "STSong", "Noto Serif CJK SC", "Source Han Serif SC", "Source Han Serif", Georgia, "Times New Roman", serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", "Helvetica Neue", Arial, sans-serif;
  --mono: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  --radius: 18px;
  --wrap: 1160px;
  --ease: cubic-bezier(.22, .72, .2, 1);
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --canvas: #11181f;
    --paper: #18212a;
    --paper-2: #1c2630;
    --sand: #243140;
    --ink: #efe9df;
    --ink-2: #d6cfc3;
    --slate: #a39f95;
    --faint: #7d7a72;
    --line: #2d3945;
    --line-soft: rgba(255, 255, 255, 0.08);
    --stone: #cec4b4;
    --stone-hi: #efe9df;
    --stone-lo: #cec4b4;
    --amber: #f1b86e;
    --amber-soft: rgba(241, 184, 110, 0.18);
    --sage: #8fb3a6;
    --shade: 0, 0, 0;
    color-scheme: dark;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 84px; }
body {
  margin: 0;
  background: var(--canvas);
  color: var(--ink);
  font: 16px/1.75 var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
/* 一层很淡的纸纹，只在大面积空白里看得出来。 */
body::before {
  content: "";
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  opacity: .5;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 .45 0 0 0 0 .38 0 0 0 0 .28 0 0 0 .05 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; }
b, strong { font-weight: 600; }
h1, h2, h3 { font-family: var(--serif); font-weight: 600; letter-spacing: .01em; margin: 0; color: var(--ink); }
p { margin: 0; }
em { font-style: normal; color: var(--amber); }
::selection { background: var(--amber-soft); }
:focus-visible { outline: 2px solid var(--amber); outline-offset: 3px; border-radius: 6px; }

.wrap { width: min(var(--wrap), 100% - 40px); margin-inline: auto; }
.skip { position: absolute; left: -999px; top: 8px; padding: 8px 14px; background: var(--paper); border: 1px solid var(--line); border-radius: 10px; z-index: 100; }
.skip:focus { left: 16px; }

/* ── 材质 ─────────────────────────────────────── */
.paper {
  background: var(--paper);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  box-shadow: 0 1px 2px rgba(var(--shade), .05), 0 18px 40px -22px rgba(var(--shade), .30);
}
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  height: 50px; padding: 0 24px; border-radius: 999px;
  font: 600 15px/1 var(--sans); text-decoration: none; letter-spacing: .02em;
  transition: transform .2s var(--ease), box-shadow .2s var(--ease), background .2s;
  cursor: pointer; border: 0;
}
.btn-stone {
  color: #fff;
  background: linear-gradient(180deg, #3a5669, #22394a);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.16), 0 1px 1px rgba(34,57,74,.25), 0 12px 24px -12px rgba(34,57,74,.55);
}
.btn-stone:hover { transform: translateY(-1px); box-shadow: inset 0 1px 0 rgba(255,255,255,.16), 0 2px 2px rgba(34,57,74,.25), 0 16px 28px -12px rgba(34,57,74,.6); }
.btn-stone:active { transform: translateY(0); }
@media (prefers-color-scheme: dark) {
  .btn-stone { color: #1a232b; background: linear-gradient(180deg, #efe9df, #cec4b4); box-shadow: inset 0 1px 0 rgba(255,255,255,.5), 0 12px 24px -12px rgba(0,0,0,.7); }
}
.btn-line { color: var(--ink); background: var(--paper); border: 1px solid var(--line); box-shadow: 0 1px 2px rgba(var(--shade), .05); }
.btn-line:hover { border-color: var(--slate); }
.btn .arrow { transition: transform .2s var(--ease); }
.btn:hover .arrow { transform: translate(2px, -2px); }
.link-quiet { color: var(--slate); text-decoration: none; font-weight: 500; }
.link-quiet:hover { color: var(--ink); }

/* ── 导航 ─────────────────────────────────────── */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--canvas) 94%, transparent);
  border-bottom: 1px solid transparent;
  transition: border-color .25s, background .25s;
}
.nav.scrolled { border-bottom-color: var(--line-soft); background: var(--canvas); }
.nav-inner { display: flex; align-items: center; gap: 28px; height: 68px; }
.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; font: italic 600 23px/1 var(--serif); letter-spacing: .01em; }
.brand img { width: 30px; height: auto; }
.nav-links { display: flex; gap: 26px; margin-left: 18px; }
.nav-links a { color: var(--slate); text-decoration: none; font-size: 14.5px; font-weight: 500; transition: color .2s; }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--ink); }
.nav-actions { margin-left: auto; display: flex; align-items: center; gap: 18px; }
.nav-actions .btn { height: 40px; padding: 0 18px; font-size: 14px; }

/* ── 通用段落 ─────────────────────────────────── */
.section { padding: 120px 0; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  font: 600 12.5px/1 var(--sans); letter-spacing: .18em; text-transform: uppercase; color: var(--sage);
}
.eyebrow::before { content: ""; width: 18px; height: 6px; border-radius: 3px; background: var(--amber); transform: rotate(-4deg); }
.section-head { max-width: 720px; margin-bottom: 56px; }
.section-head h2 { font-size: clamp(30px, 4vw, 46px); line-height: 1.22; margin: 18px 0 18px; }
.section-head p { color: var(--slate); font-size: 17px; }
.center { text-align: center; margin-inline: auto; }
.center .eyebrow { justify-content: center; }

.reveal { opacity: 0; transform: translateY(18px); transition: opacity .8s var(--ease), transform .8s var(--ease); }
.reveal.in { opacity: 1; transform: none; }

/* ── 首屏 ─────────────────────────────────────── */
.hero > *, .morph-wrap > *, .ask-grid > *, .shelf-area > *, .grow > * { min-width: 0; }
.hero { display: grid; grid-template-columns: 1.02fr 1fr; gap: 56px; align-items: center; padding: 72px 0 96px; min-height: min(calc(100vh - 68px), 860px); }
.hero h1 { font-size: clamp(46px, 6.4vw, 84px); line-height: 1.08; margin: 22px 0 26px; letter-spacing: .02em; }
.hero-lead { color: var(--ink-2); font-size: 18px; line-height: 1.85; max-width: 520px; }
.hero-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 22px; margin-top: 38px; }
.inputs { display: flex; flex-wrap: wrap; gap: 8px 18px; margin-top: 44px; color: var(--slate); font-size: 13.5px; }
.inputs span { display: inline-flex; align-items: center; gap: 7px; }
.inputs svg { width: 17px; height: 17px; color: var(--sage); }

.stage { position: relative; aspect-ratio: 1 / 1.02; max-width: 560px; margin-left: auto; width: 100%; }
.stage-page { position: absolute; right: 0; top: 4%; width: 58%; padding: 26px 26px 22px; transform: rotate(1.5deg); }
.stage-page .crumb { font-size: 12px; color: var(--faint); letter-spacing: .06em; }
.stage-page h3 { font-size: 21px; margin: 6px 0 16px; }
.toc { list-style: none; margin: 0; padding: 0; font-size: 14px; }
.toc li { display: flex; align-items: baseline; gap: 10px; padding: 7px 0; border-bottom: 1px dashed var(--line-soft); color: var(--ink-2); }
.toc li:last-child { border-bottom: 0; }
.toc .no { font: 500 12.5px/1 var(--mono); color: var(--faint); min-width: 30px; }
.toc .ch { font-family: var(--serif); font-weight: 600; color: var(--ink); }
.toc .fresh { margin-left: auto; font-size: 11px; font-weight: 600; color: var(--amber); letter-spacing: .06em; }
.toc li.new { background: linear-gradient(90deg, var(--amber-soft), transparent 80%); border-radius: 6px; padding-inline: 6px; margin-inline: -6px; }

.cover {
  position: absolute; left: 2%; top: 20%; width: 40%; aspect-ratio: 3 / 4.1;
  border-radius: 6px 12px 12px 6px;
  background:
    linear-gradient(90deg, rgba(0,0,0,.22) 0 9%, rgba(255,255,255,.06) 9% 10%, transparent 10%),
    repeating-linear-gradient(45deg, rgba(255,255,255,.035) 0 2px, transparent 2px 5px),
    var(--cloth, var(--cloth-1));
  box-shadow: 0 2px 3px rgba(var(--shade), .2), 0 30px 50px -24px rgba(var(--shade), .55);
  transform: rotate(-4deg);
  color: #f3ede2;
  padding: 26px 18px 18px 30px;
  display: flex; flex-direction: column;
}
.cover::after { /* 琥珀燕尾书签带，右上 74% 处 */
  content: ""; position: absolute; top: -2px; left: 74%; width: 16px; height: 64px;
  background: linear-gradient(180deg, #f1b86e, #cc8438);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 50% 84%, 0 100%);
  box-shadow: 0 2px 2px rgba(0,0,0,.2);
}
.cover .title { font: 600 clamp(17px, 2vw, 22px)/1.35 var(--serif); letter-spacing: .06em; }
.cover .sub { margin-top: 8px; font-size: 11.5px; opacity: .72; letter-spacing: .12em; }
.cover .mark { margin-top: auto; width: 34px; opacity: .85; }

.cairn { position: absolute; left: 26%; bottom: 1%; width: 64%; }
.pebble {
  position: relative; display: flex; align-items: center; gap: 10px;
  width: fit-content; padding: 11px 20px 11px 12px; border-radius: 999px;
  background: var(--paper); border: 1px solid var(--line-soft);
  box-shadow: 0 1px 2px rgba(var(--shade), .08), 0 14px 26px -14px rgba(var(--shade), .38);
  font-size: 13.5px; color: var(--ink-2); white-space: nowrap;
}
.pebble i { width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center; background: var(--sand); color: var(--stone); flex: none; }
.pebble i svg { width: 16px; height: 16px; }
.pebble b { color: var(--ink); font-weight: 600; }
.pebble.p1 { margin-left: 16%; transform: rotate(-5.5deg); background: linear-gradient(180deg, #f6c887, #d8944a); color: #3b2a14; border-color: transparent; }
.pebble.p1 b { color: #2b1d0c; }
.pebble.p1 i { background: rgba(255,255,255,.35); color: #5a3a14; }
.pebble.p2 { margin: 8px 0 0 6%; transform: rotate(4deg); }
.pebble.p3 { margin-top: 8px; transform: rotate(-2deg); padding-right: 30px; }
.stage .note { position: absolute; left: 0; top: 0; font: italic 500 14px/1.5 var(--serif); color: var(--slate); max-width: 180px; }
.stage .note::after { content: ""; display: block; width: 46px; height: 1px; background: var(--line); margin-top: 10px; }

@media (prefers-reduced-motion: no-preference) {
  .stage .pebble, .stage .cover, .stage .stage-page { animation: settle 1s var(--ease) both; }
  .stage .stage-page { animation-delay: .05s; }
  .stage .cover { animation-delay: .15s; }
  .stage .pebble.p3 { animation-delay: .45s; }
  .stage .pebble.p2 { animation-delay: .6s; }
  .stage .pebble.p1 { animation-delay: .75s; }
  .toc li.new { animation: glow 2.6s 1.4s var(--ease) both; }
}
@keyframes settle { from { opacity: 0; translate: 0 -22px; } to { opacity: 1; translate: 0 0; } }
@keyframes glow { 0% { background-color: transparent; } 30% { background-color: var(--amber-soft); } 100% { background-color: transparent; } }

/* ── 两种样子（按时间 / 写成书） ─────────────────── */
.morph-wrap { display: grid; grid-template-columns: 340px 1fr; gap: 48px; align-items: start; }
.switch { display: inline-flex; padding: 4px; border-radius: 999px; background: var(--sand); border: 1px solid var(--line-soft); }
.switch button {
  font: 600 14px/1 var(--sans); color: var(--slate); background: transparent; border: 0; cursor: pointer;
  height: 38px; padding: 0 18px; border-radius: 999px; transition: color .2s, background .25s, box-shadow .25s;
}
.switch button[aria-pressed="true"] { color: var(--ink); background: var(--paper); box-shadow: 0 1px 2px rgba(var(--shade), .12), 0 6px 14px -8px rgba(var(--shade), .4); }
.morph-side p { color: var(--slate); margin-top: 22px; font-size: 15.5px; }
.morph-side .verdict { margin-top: 26px; padding-top: 22px; border-top: 1px solid var(--line-soft); }
.morph-side .verdict li { margin: 8px 0; color: var(--ink-2); font-size: 15px; }
.morph-side ul { list-style: none; padding: 0; margin: 0; }
.morph-side .verdict li::before { content: ""; display: inline-block; width: 8px; height: 4px; border-radius: 2px; background: var(--amber); margin-right: 10px; vertical-align: middle; transform: rotate(-5deg); }
.morph-side [data-when] { display: none; }
.morph-wrap[data-mode="time"] [data-when="time"], .morph-wrap[data-mode="book"] [data-when="book"] { display: block; animation: fadein .45s var(--ease); }

.morph { padding: 28px 30px; min-height: 520px; }
.morph-list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; }
.morph-list > li { will-change: transform; }
.frag { display: flex; align-items: baseline; gap: 14px; padding: 11px 12px; border-radius: 12px; }
.frag .date { font: 500 12.5px/1 var(--mono); color: var(--faint); min-width: 44px; }
.frag .kind { font-size: 12px; color: var(--sage); border: 1px solid var(--line-soft); border-radius: 999px; padding: 3px 9px; white-space: nowrap; min-width: 72px; text-align: center; }
.frag .text { color: var(--ink-2); }
.frag .t-book { display: none; }
.frag .sec { display: none; font: 500 13px/1 var(--mono); color: var(--faint); min-width: 34px; }
.frag .from { display: none; margin-left: auto; font-size: 12px; color: var(--faint); white-space: nowrap; }
.chap { display: none; padding: 16px 12px 6px; font: 600 18px/1.3 var(--serif); color: var(--ink); }
.chap small { font: 500 12px/1 var(--sans); color: var(--faint); margin-left: 10px; letter-spacing: .08em; }
.half { color: var(--amber); font-size: 12.5px; margin-left: 6px; }
.morph[data-mode="time"] .frag { border-bottom: 1px dashed var(--line-soft); border-radius: 0; }

.morph[data-mode="book"] .chap { display: block; }
.morph[data-mode="book"] .frag { gap: 12px; }
.morph[data-mode="book"] .frag .date, .morph[data-mode="book"] .frag .kind, .morph[data-mode="book"] .half { display: none; }
.morph[data-mode="book"] .frag .sec, .morph[data-mode="book"] .frag .from { display: inline; }
.morph[data-mode="book"] .frag .t-time { display: none; }
.morph[data-mode="book"] .frag .t-book { display: inline; color: var(--ink); font-family: var(--serif); font-weight: 600; font-size: 16px; }
.morph[data-mode="book"] .frag.merged { display: none; }
.morph[data-mode="book"] .frag.joined .from { color: var(--amber); }
.morph[data-mode="book"] .frag.joined { background: linear-gradient(90deg, var(--amber-soft), transparent 75%); }
.morph[data-mode="book"] li[data-o] { order: var(--o); }

/* ── 三种整理法 ───────────────────────────────── */
.ways { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.way { padding: 28px 28px 30px; }
.way figure { margin: 0 0 22px; height: 150px; border-radius: 12px; background: var(--paper-2); border: 1px solid var(--line-soft); display: grid; place-items: center; }
.way figure svg { width: 82%; height: 82%; color: var(--faint); }
.way .tag { font-size: 12px; font-weight: 600; letter-spacing: .14em; color: var(--faint); }
.way h3 { font-size: 22px; margin: 8px 0 10px; }
.way p { color: var(--slate); font-size: 15px; }
.way.ours { border-color: color-mix(in srgb, var(--amber) 45%, transparent); }
.way.ours figure { background: color-mix(in srgb, var(--amber-soft) 50%, var(--paper-2)); }
.way.ours figure svg { color: var(--stone); }
.way.ours .tag { color: var(--amber); }

/* ── 交到第十次 ───────────────────────────────── */
.grow { display: grid; grid-template-columns: 1fr 1.15fr; gap: 0; overflow: hidden; }
.grow-left { padding: 40px; border-right: 1px solid var(--line-soft); display: flex; flex-direction: column; }
.grow-left h3 { font-size: 26px; margin-bottom: 10px; }
.grow-left p { color: var(--slate); font-size: 15.5px; }
.counter { margin-top: 34px; font: 600 64px/1 var(--serif); color: var(--ink); }
.counter small { font: 500 15px/1 var(--sans); color: var(--slate); margin-left: 8px; }
.range { -webkit-appearance: none; appearance: none; width: 100%; height: 6px; border-radius: 3px; margin: 26px 0 10px; background: linear-gradient(90deg, var(--amber) 0 var(--p, 0%), var(--sand) var(--p, 0%)); cursor: pointer; }
.range::-webkit-slider-thumb { -webkit-appearance: none; width: 26px; height: 18px; border-radius: 9px; background: linear-gradient(180deg, #3a5669, #22394a); box-shadow: inset 0 1px 0 rgba(255,255,255,.2), 0 4px 10px rgba(34,57,74,.35); transform: rotate(-5deg); }
.range::-moz-range-thumb { width: 26px; height: 18px; border: 0; border-radius: 9px; background: linear-gradient(180deg, #3a5669, #22394a); }
.ticks { display: flex; justify-content: space-between; font: 500 11.5px/1 var(--mono); color: var(--faint); }
.stack { flex: 1; display: flex; flex-direction: column-reverse; align-items: center; justify-content: flex-start; gap: 5px; padding: 26px 0 6px; min-height: 250px; }
.stack .stone { height: 20px; border-radius: 10px; background: linear-gradient(180deg, #46657a, #2c4759); box-shadow: inset 0 1px 0 rgba(255,255,255,.14), 0 3px 6px -3px rgba(34,57,74,.5); transition: opacity .35s, transform .35s var(--ease); display: grid; place-items: center; font: 500 10.5px/1 var(--mono); color: rgba(255,255,255,.72); }
.stack .stone:nth-child(odd) { transform: rotate(-2deg) translateX(-6px); }
.stack .stone:nth-child(even) { transform: rotate(2.5deg) translateX(8px); }
.stack .stone.top { background: linear-gradient(180deg, #f1b86e, #cc8438); color: #3b2a14; }
.stack .stone[hidden] { display: none; }
@media (prefers-color-scheme: dark) { .stack .stone { background: linear-gradient(180deg, #efe9df, #cec4b4); color: #1a232b; } }
.lastin { padding-top: 18px; font-size: 14px; color: var(--slate); border-top: 1px dashed var(--line-soft); }
.lastin b { color: var(--ink); }
.lastin .to { color: var(--amber); font-weight: 600; }
.grow-right { padding: 36px 40px; background: var(--paper-2); }
.grow-right .crumb { font-size: 12px; color: var(--faint); letter-spacing: .06em; }
.grow-right h4 { font: 600 20px/1.3 var(--serif); margin: 6px 0 18px; }
.growtoc { list-style: none; margin: 0; padding: 0; }
.growtoc li { display: flex; gap: 10px; align-items: baseline; font-size: 14.5px; color: var(--ink-2); padding: 5px 6px; margin: 0 -6px; border-radius: 6px; transition: background .5s; }
.growtoc li.ch { margin-top: 12px; font: 600 16px/1.4 var(--serif); color: var(--ink); }
.growtoc li.ch:first-child { margin-top: 0; }
.growtoc .no { font: 500 12.5px/1 var(--mono); color: var(--faint); min-width: 30px; }
.growtoc li.sec { padding-left: 26px; }
.growtoc li.hit { background: var(--amber-soft); }
.growtoc li.hit::after { content: "新"; margin-left: auto; font-size: 11px; font-weight: 700; color: var(--amber); }
.growtoc li[hidden] { display: none; }

/* ── 书架（用途） ─────────────────────────────── */
.shelf-area { display: grid; grid-template-columns: 1.05fr 1fr; gap: 56px; align-items: end; }
.shelf { position: relative; display: flex; align-items: flex-end; gap: 14px; height: 320px; padding: 0 28px; }
.shelf::after { content: ""; position: absolute; left: 0; right: 0; bottom: -14px; height: 14px; border-radius: 3px; background: linear-gradient(180deg, #cdbfa8, #b9a98f); box-shadow: 0 16px 24px -14px rgba(var(--shade), .5); }
@media (prefers-color-scheme: dark) { .shelf::after { background: linear-gradient(180deg, #33414e, #26323d); } }
.spine {
  position: relative; flex: none; width: var(--w, 66px); height: var(--h, 82%);
  border: 0; padding: 18px 0 16px; cursor: pointer;
  border-radius: 5px 5px 2px 2px;
  background:
    linear-gradient(90deg, rgba(0,0,0,.18), rgba(255,255,255,.07) 30%, rgba(0,0,0,.12)),
    repeating-linear-gradient(45deg, rgba(255,255,255,.03) 0 2px, transparent 2px 5px),
    var(--c);
  color: #f5efe4;
  box-shadow: 0 2px 2px rgba(0,0,0,.14);
  display: flex; flex-direction: column; align-items: center; justify-content: space-between;
  transition: transform .45s var(--ease), box-shadow .45s var(--ease);
  font-family: var(--serif);
}
.spine .v { writing-mode: vertical-rl; font-size: 17px; font-weight: 600; letter-spacing: .3em; }
.spine.deco { cursor: default; pointer-events: none; }
.spine.deco .band { opacity: .5; }
.bookend { flex: none; width: 34px; height: 46%; margin-left: 6px; border-radius: 4px 4px 2px 2px; background: linear-gradient(180deg, #cfc5b5, #b8ab96); box-shadow: 0 2px 2px rgba(0,0,0,.1); }
@media (prefers-color-scheme: dark) { .bookend { background: linear-gradient(180deg, #3a4753, #2c3742); } }
.spine .band { width: 70%; height: 3px; border-radius: 2px; background: rgba(241,184,110,.85); }
.spine:hover { transform: translateY(-8px); }
.spine[aria-pressed="true"] { transform: translateY(-34px) rotate(-3deg); box-shadow: 0 26px 30px -16px rgba(var(--shade), .6); }
.spine.lean { transform: rotate(6deg); transform-origin: bottom right; }
.spine.lean[aria-pressed="true"] { transform: translateY(-34px) rotate(2deg); }
.shelf-card { padding: 34px 36px; min-height: 250px; }
.shelf-card .tag { font-size: 12px; font-weight: 600; letter-spacing: .14em; color: var(--amber); }
.shelf-card h3 { font-size: 28px; margin: 10px 0 14px; }
.shelf-card p { color: var(--ink-2); }
.shelf-card .eg { margin-top: 18px; padding-top: 16px; border-top: 1px dashed var(--line); color: var(--slate); font-size: 14.5px; }
.shelf-card [data-goal] { display: none; }
.shelf-card [data-goal].on { display: block; animation: fadein .45s var(--ease); }
@keyframes fadein { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
.shelf-hint { margin-top: 40px; font-size: 13px; color: var(--faint); }

/* ── 问它（深色墨蓝带） ───────────────────────── */
.ask { background: #1d2f3c; color: #e9e3d8; position: relative; overflow: hidden; }
.ask::before { content: ""; position: absolute; inset: 0; background: radial-gradient(900px 480px at 85% 10%, rgba(241,184,110,.10), transparent 60%); pointer-events: none; }
@media (prefers-color-scheme: dark) { .ask { background: #0c1218; } }
.ask .eyebrow { color: #9fc0b3; }
.ask h2 { color: #f5efe4; }
.ask .section-head p { color: #b5b0a5; }
.ask-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: start; position: relative; }
.chat { display: flex; flex-direction: column; gap: 16px; }
.bubble { max-width: 92%; padding: 16px 20px; border-radius: 18px; font-size: 15.5px; line-height: 1.8; }
.bubble.q { align-self: flex-end; background: #2a4152; color: #f1ece3; border-bottom-right-radius: 6px; }
.bubble.a { background: #f8f4ec; color: #1f2833; border-bottom-left-radius: 6px; box-shadow: 0 24px 40px -24px rgba(0,0,0,.6); }
.cite {
  display: inline-flex; align-items: center; gap: 6px; margin: 0 4px; padding: 2px 10px 2px 8px;
  border-radius: 999px; border: 1px solid rgba(204,132,56,.45); background: rgba(241,184,110,.18);
  font: 600 13px/1.7 var(--sans); color: #8a5520; cursor: pointer; vertical-align: 1px;
  transition: background .2s, transform .2s;
}
.cite:hover { background: rgba(241,184,110,.32); }
.cite svg { width: 13px; height: 13px; }
.cite[aria-expanded="true"] { background: #cc8438; color: #fff; border-color: #cc8438; }
.nothing { font-size: 14px; color: #a6a196; padding-left: 4px; }
.nothing b { color: #e9e3d8; font-weight: 600; }

.book-page {
  position: relative; background: #fbf8f1; color: #1f2833; border-radius: 6px 16px 16px 6px; padding: 30px 32px 34px;
  box-shadow: 0 30px 60px -30px rgba(0,0,0,.75);
  transform-origin: left center; transition: transform .7s var(--ease), opacity .5s;
  min-height: 360px;
}
.book-page::before { content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 18px; border-radius: 6px 0 0 6px; background: linear-gradient(90deg, rgba(0,0,0,.08), transparent); }
.book-page.closed { transform: perspective(1400px) rotateY(-78deg); opacity: 0; }
.book-page .crumb { font-size: 12px; color: #8b877c; letter-spacing: .04em; }
.book-page h3 { font: 600 22px/1.3 var(--serif); margin: 8px 0 14px; color: #18202c; }
.book-page p { font-size: 14.5px; color: #3c4552; margin: 10px 0; }
.book-page mark { background: linear-gradient(transparent 55%, rgba(241,184,110,.55) 55%); color: inherit; padding: 0 1px; }
.book-page table { width: 100%; border-collapse: collapse; margin-top: 14px; font-size: 13.5px; }
.book-page th, .book-page td { text-align: left; padding: 8px 10px; border-bottom: 1px solid #e3dccf; }
.book-page th { font-weight: 600; color: #6f746f; font-size: 12.5px; }
.book-page td code { font: 500 12.5px/1 var(--mono); background: #efe9df; padding: 2px 6px; border-radius: 5px; }
.book-page .placeholder { position: absolute; inset: 0; display: grid; place-items: center; color: #8b877c; font-size: 14px; }

/* ── 定价 ─────────────────────────────────────── */
.plans { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; align-items: stretch; }
.plan { position: relative; display: flex; flex-direction: column; padding: 32px 30px 30px; }
.plan .name { font: 600 24px/1 var(--serif); }
.plan .for { color: var(--slate); font-size: 14.5px; margin-top: 10px; min-height: 46px; }
.plan .price { margin: 20px 0 4px; font: 600 44px/1 var(--serif); }
.plan .price small { font: 500 15px/1 var(--sans); color: var(--slate); margin-left: 4px; }
.plan .annual { font-size: 13px; color: var(--faint); min-height: 20px; }
.plan ul { list-style: none; padding: 0; margin: 24px 0 28px; border-top: 1px solid var(--line-soft); }
.plan li { padding: 11px 0 11px 22px; border-bottom: 1px dashed var(--line-soft); font-size: 14.5px; color: var(--ink-2); position: relative; }
.plan li::before { content: ""; position: absolute; left: 0; top: 20px; width: 9px; height: 5px; border-radius: 3px; background: var(--sage); transform: rotate(-5deg); }
.plan .btn { margin-top: auto; justify-content: center; }
.plan.featured { border: 1px solid color-mix(in srgb, var(--stone) 40%, transparent); box-shadow: 0 1px 2px rgba(var(--shade), .06), 0 30px 60px -28px rgba(var(--shade), .5); }
.plan.featured li::before { background: var(--amber); }
.plan .badge { position: absolute; top: -13px; left: 30px; padding: 5px 12px; border-radius: 999px; font-size: 12px; font-weight: 600; color: #3b2a14; background: linear-gradient(180deg, #f6c887, #d8944a); box-shadow: 0 6px 14px -6px rgba(204,132,56,.7); }
.plans-note { margin-top: 26px; text-align: center; color: var(--faint); font-size: 13.5px; }

/* ── 收尾 ─────────────────────────────────────── */
.closing { text-align: center; padding: 120px 0 130px; }
.closing img { width: 92px; margin: 0 auto 30px; }
.closing h2 { font-size: clamp(34px, 5vw, 58px); line-height: 1.2; margin-bottom: 36px; }

.footer { display: flex; align-items: center; gap: 22px; padding: 30px 0 44px; border-top: 1px solid var(--line-soft); color: var(--faint); font-size: 13.5px; }
.footer .brand { font-size: 19px; color: var(--ink); }
.footer .brand img { width: 24px; }
.footer nav { margin-left: auto; display: flex; gap: 22px; }
.footer nav a { text-decoration: none; color: var(--slate); }
.footer nav a:hover { color: var(--ink); }

/* ── 下载页 ───────────────────────────────────── */
.dl-hero { padding: 96px 0 60px; max-width: 760px; }
.dl-hero h1 { font-size: clamp(42px, 5.6vw, 70px); line-height: 1.12; margin: 20px 0 22px; }
.dl-hero p { color: var(--ink-2); font-size: 18px; }
.devices { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.device { padding: 30px; display: flex; flex-direction: column; min-height: 280px; }
.device .ico { width: 54px; height: 54px; border-radius: 16px; display: grid; place-items: center; background: var(--sand); color: var(--stone); margin-bottom: 26px; }
.device .ico svg { width: 26px; height: 26px; }
.device h3 { font-size: 22px; margin-bottom: 10px; }
.device p { color: var(--slate); font-size: 15px; }
.status { margin-top: auto; padding-top: 22px; display: inline-flex; align-items: center; gap: 8px; font-size: 13px; font-weight: 600; color: var(--amber); }
.status i { width: 8px; height: 8px; border-radius: 50%; background: var(--amber); box-shadow: 0 0 0 4px var(--amber-soft); }
.notify { margin: 64px 0 110px; padding: 42px 44px; display: flex; align-items: center; gap: 30px; }
.notify h2 { font-size: 26px; margin-bottom: 8px; }
.notify p { color: var(--slate); }
.notify .btn { margin-left: auto; flex: none; }

/* ── 隐私政策 ─────────────────────────────────── */
.policy-hero { padding: 84px 0 40px; }
.policy-hero h1 { font-size: clamp(38px, 5vw, 58px); margin: 18px 0 12px; }
.policy-date { color: var(--faint); font-size: 14px; }
.policy-layout { display: grid; grid-template-columns: 240px 1fr; gap: 56px; align-items: start; padding-bottom: 110px; }
.policy-toc { position: sticky; top: 96px; }
.policy-toc h2 { font: 600 12px/1 var(--sans); letter-spacing: .16em; color: var(--faint); margin-bottom: 14px; }
.policy-toc ol { list-style: none; padding: 0; margin: 0; counter-reset: t; }
.policy-toc li { counter-increment: t; }
.policy-toc a { display: flex; gap: 10px; padding: 7px 10px; border-radius: 9px; text-decoration: none; color: var(--slate); font-size: 14px; }
.policy-toc a::before { content: counter(t, decimal-leading-zero); font: 500 12px/1.8 var(--mono); color: var(--faint); }
.policy-toc a:hover { color: var(--ink); background: var(--paper); }
.policy-toc a.current { color: var(--ink); background: var(--paper); box-shadow: inset 3px 0 0 var(--amber); }
.policy-article { padding: 44px 50px; }
.policy-article > p { color: var(--ink-2); font-size: 16.5px; }
.policy-article section { padding-top: 34px; margin-top: 34px; border-top: 1px dashed var(--line); }
.policy-article h2 { font-size: 23px; margin-bottom: 14px; }
.policy-article p, .policy-article li { color: var(--ink-2); font-size: 15.5px; }
.policy-article p + p { margin-top: 10px; }
.policy-article ul { padding-left: 20px; margin: 10px 0; }
.policy-article li { margin: 7px 0; }
.policy-note { margin-top: 16px; padding: 16px 20px; border-radius: 12px; background: var(--amber-soft); color: var(--ink); font-size: 15px; }
.policy-mail { color: var(--stone); font-weight: 600; }

/* ── 窄屏 ─────────────────────────────────────── */
@media (max-width: 1000px) {
  .hero { grid-template-columns: 1fr; min-height: 0; padding-top: 48px; }
  .stage { margin: 10px auto 0; }
  .morph-wrap, .grow, .shelf-area, .ask-grid { grid-template-columns: 1fr; }
  .grow-left { border-right: 0; border-bottom: 1px solid var(--line-soft); }
  .ways, .plans, .devices { grid-template-columns: 1fr; }
  .plan .for { min-height: 0; }
  .policy-layout { grid-template-columns: 1fr; }
  .policy-toc { position: static; }
  .nav-links { display: none; }
}
@media (max-width: 640px) {
  .section { padding: 84px 0; }
  .wrap { width: min(var(--wrap), 100% - 32px); }
  .hero h1 { font-size: 46px; }
  .hero-lead { font-size: 16.5px; }
  .stage { aspect-ratio: 1 / 1.42; }
  .stage-page { width: 80%; top: 0; padding: 18px 18px 12px; }
  .stage-page h3 { font-size: 18px; margin-bottom: 8px; }
  .toc { font-size: 13px; }
  .toc li { padding: 5px 0; }
  .toc li:nth-child(n+5) { display: none; }
  .cover { width: 42%; top: 55%; left: 0; padding: 18px 12px 12px 22px; }
  .cover .sub { display: none; }
  .cairn { left: 36%; bottom: 3%; width: 64%; }
  .pebble { font-size: 11.5px; padding: 7px 12px 7px 7px; gap: 7px; white-space: normal; }
  .pebble i { width: 24px; height: 24px; }
  .pebble.p1 { margin-left: 8%; }
  .pebble.p2 { margin-left: 0; }
  .stage .note { display: none; }
  .morph { padding: 16px 12px; }
  .frag { flex-wrap: wrap; gap: 8px; }
  .shelf { gap: 8px; padding: 0 10px; height: 260px; }
  .spine { --w: 52px !important; }
  .policy-article { padding: 26px 22px; }
  .notify { flex-direction: column; align-items: flex-start; padding: 30px 26px; }
  .notify .btn { margin-left: 0; }
  .footer { flex-wrap: wrap; }
  .footer nav { margin-left: 0; width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  * { animation: none !important; transition: none !important; }
}