@charset "UTF-8";

/* 与首版纸面共用基础字体与颜色；物件仅在访客操作时运动。 */
[hidden] { display: none !important; }
button:disabled { cursor: default; }
a, button { -webkit-tap-highlight-color: transparent; }
.site-header a, .chapter-nav a, .return-link, .next-stop a, .back-top, .walk-link { min-height: 44px; display: inline-flex; align-items: center; }
.site-header { position: relative; z-index: 2; }
.site-header nav { gap: 1.7rem; }
.brand { white-space: nowrap; }
.wander { padding: 2.5rem 0 5rem; }
.chapter-list { display: grid; grid-template-columns: 1fr 1fr; border-top: 1px solid var(--line); }
.chapter-link { display: grid; grid-template-columns: 2rem 1fr 1rem; gap: 1.25rem; align-items: center; padding: 2rem 1.5rem 2rem 0; border-bottom: 1px solid var(--line); }
.chapter-link:nth-child(even) { padding-left: 2.5rem; }
.chapter-link .chapter-no { color: var(--muted); font-family: var(--serif); font-size: .8rem; }
.chapter-link h3 { font: 400 1.35rem/1.5 var(--serif); letter-spacing: .04em; }
.chapter-link p { margin-top: .5rem; font-size: .75rem; color: var(--muted); }
.chapter-link .arrow { font-size: 1.3rem; transition: transform 180ms ease; }
.chapter-link:active { opacity: .65; }
.note-destination { display: inline-flex; align-items: center; min-height: 44px; margin-top: .8rem; gap: 1rem; font-size: .72rem; }
.return-link { gap: .8rem; font-size: .75rem; }
.chapter-nav { display: flex; flex-wrap: wrap; gap: .4rem 2rem; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); padding: .5rem 0; font-size: .72rem; letter-spacing: .06em; }
.chapter-nav a { color: var(--muted); position: relative; }
.chapter-nav a[aria-current="page"] { color: var(--ink); }
.chapter-nav a[aria-current="page"]::after { content: ""; position: absolute; height: 2px; background: #829071; bottom: 0; left: 0; right: 0; }
.chapter-hero { display: grid; grid-template-columns: .75fr 1.25fr; gap: 6%; align-items: center; padding: 4rem 0 4.5rem; }
.chapter-copy { padding-left: 3%; }
.chapter-copy h1 { font: 400 clamp(2.4rem, 4.3vw, 4rem)/1.4 var(--serif); letter-spacing: .025em; margin: 1.5rem 0; }
.chapter-copy h1 span { display: block; }
.chapter-intro { font: 400 1.1rem/2 var(--serif); letter-spacing: .05em; }
.chapter-description { color: var(--muted); font-size: .78rem; line-height: 2.1; margin-top: 1.2rem; }
.margin-note { display: flex; align-items: center; gap: .7rem; margin-top: 2.6rem; font-size: .63rem; letter-spacing: .06em; color: var(--muted); }
.margin-note::before { content: ""; width: 1.8rem; height: 1px; background: #a9b09b; }
.exhibit { min-width: 0; }
.stage { position: relative; min-height: 400px; border-radius: 48% 48% 4px 4px; overflow: hidden; isolation: isolate; }
.stage::after { content: ""; position: absolute; inset: 0; border: 1px solid #34483d0a; border-radius: inherit; pointer-events: none; }
.stage-marker { position: absolute; right: 1.8rem; top: 44%; writing-mode: vertical-rl; font: .75rem/1.8 var(--serif); letter-spacing: .25em; color: #5a6c58; }
.exhibit-caption { display: flex; justify-content: space-between; gap: .8rem; padding: .85rem .1rem; font-size: .62rem; color: var(--muted); letter-spacing: .08em; }
.controls { display: flex; align-items: center; justify-content: center; flex-wrap: wrap; gap: .55rem; margin-top: 1.2rem; }
.pill { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; background: #fafbf4b3; border: 1px solid #cbd3c3; border-radius: 2rem; padding: .55rem 1.1rem; font-size: .75rem; gap: .6rem; }
.pill[aria-pressed="true"], .pill.primary { background: #405745; color: #fafbf4; border-color: #405745; }
.pill:active { transform: scale(.97); }
.interaction-status { min-height: 3.5em; max-width: 30rem; margin: 1rem auto 0; padding: 0 .5rem; text-align: center; font-size: .74rem; line-height: 1.8; color: var(--muted); }
.field-entry { display: grid; grid-template-columns: .75fr 1.25fr; gap: 6%; border-top: 1px solid var(--line); padding: 3rem 0 3.8rem; }
.entry-meta { display: flex; flex-direction: column; gap: .75rem; font-size: .7rem; color: var(--muted); letter-spacing: .06em; }
.entry-meta h2 { color: var(--ink); font: 400 1.2rem/1.5 var(--serif); margin-bottom: .5rem; }
.entry-prose p { font: 400 1.05rem/2.2 var(--serif); letter-spacing: .04em; }
.entry-prose .postscript { font: .72rem/1.9 system-ui, sans-serif; color: var(--muted); margin-top: 1rem; }
.next-stop { display: flex; justify-content: space-between; align-items: center; gap: 1.5rem; padding: 2rem 0; border-top: 1px solid var(--line); }
.next-stop p { font-size: .64rem; letter-spacing: .12em; color: var(--muted); }
.next-stop a { gap: 2rem; font: 400 1.25rem/1.5 var(--serif); }
.chapter-page footer { border-top: 0; padding-top: 1rem; }
.no-script { font-size: .75rem; line-height: 1.8; padding: 1rem; background: #e9ece1; margin: 1rem 0; }

/* 风声：三种材质，沿同一横枝悬挂。 */
.wind-stage { background: radial-gradient(ellipse at 55% 10%, #f6f7e9, #dce5d5 65%, #c4d1bd); min-height: 440px; }
.wind-branch { position: absolute; left: 0; top: 28px; width: 100%; height: 100px; color: #647653; }
.wind-bells { display: flex; align-items: flex-start; justify-content: center; gap: 5%; padding: 48px 12% 38px 6%; }
.chime { width: 27%; border: 0; background: transparent; padding: 0; }
.chime:active { transform: none; }
.chime:active svg { opacity: .65; }
.chime-art { width: 100%; height: 290px; overflow: visible; transform-origin: 50% 0; }
.chime:nth-child(2) .chime-art { height: 318px; }
.chime:nth-child(3) .chime-art { height: 278px; }
.chime-name { display: block; font: .95rem/1.5 var(--serif); margin-top: .6rem; }
.chime-sound { display: block; font-size: .6rem; color: #5e6d57; margin-top: .5rem; letter-spacing: .14em; }
.wind-stage .stage-marker { right: 1.2rem; }

/* 云：轨道与指针共用一个坐标空间；云的姿态只由 JS 弹簧控制。 */
.cloud-stage { min-height: 420px; background: linear-gradient(#d8e5e1, #edf0e5 73%, #d7dfcf); }
.cloud-sun { position: absolute; width: 4.4rem; height: 4.4rem; background: #f8f7e8; border-radius: 50%; right: 22%; top: 15%; opacity: .8; }
.cloud-hills { position: absolute; width: 100%; height: 45%; bottom: 0; }
.cloud-track { position: absolute; left: 10%; right: 10%; top: 30%; height: 160px; }
.cloud { position: absolute; width: 148px; height: 110px; left: 0; top: 0; border: 0; padding: 0; background: transparent; touch-action: pan-y; cursor: grab; user-select: none; -webkit-user-select: none; }
.cloud-track:not([data-ready]) .cloud { left: 50%; transform: translateX(-50%); }
.cloud:active { transform: none; cursor: grabbing; }
.cloud svg { width: 100%; height: 100%; overflow: visible; filter: drop-shadow(0 11px 12px #53756312); }
.cloud.is-dragging svg { opacity: .85; }
.cloud:focus-visible { outline-offset: 2px; border-radius: 50%; }
.cloud-stations { position: absolute; left: 11%; right: 11%; bottom: 16%; display: flex; justify-content: space-between; font-size: .62rem; color: #4d6557; }
.cloud-stations span { position: relative; padding-top: 1rem; }
.cloud-stations span::before { content: ""; position: absolute; width: 4px; height: 4px; border: 1px solid #69806a; border-radius: 50%; left: calc(50% - 2px); top: 0; }
.cloud-stations span[data-active]::before { background: #69806a; }
.cloud-help { text-align: center; font-size: .65rem; color: var(--muted); margin-top: .5rem; }

/* 叶片：正反两面始终共用一张可中断的卡片。 */
.leaf-stage { min-height: 445px; background: #e6e8db; border-radius: 4px; display: grid; place-items: center; padding: 2rem; perspective: 1200px; }
.leaf-card { position: relative; width: min(100%, 300px); height: 357px; padding: 0; background: transparent; border: 0; border-radius: 2px; transform-style: preserve-3d; }
.leaf-card:active { transform: none; }
.leaf-card-inner { position: absolute; inset: 0; transform-style: preserve-3d; }
.leaf-face { position: absolute; inset: 0; background: #f8f6ed; border: 1px solid #d6d7c7; border-radius: 2px; backface-visibility: hidden; -webkit-backface-visibility: hidden; box-shadow: 0 10px 18px -15px #43543d6b; padding: 1.5rem; text-align: left; }
.leaf-back { transform: rotateY(180deg); display: flex; flex-direction: column; justify-content: center; }
.leaf-number { font-size: .63rem; color: var(--muted); letter-spacing: .1em; }
.leaf-art { width: 100%; height: 233px; }
.leaf-bottom { display: flex; justify-content: space-between; gap: .5rem; font: .82rem/1.5 var(--serif); }
.leaf-bottom span:last-child { color: var(--muted); font: .62rem/1.8 system-ui, sans-serif; }
.leaf-back-title { display: block; font: 400 1.4rem/1.5 var(--serif); margin: 1rem 0; }
#leaf-note { display: block; font: .92rem/2.2 var(--serif); }
.leaf-back .leaf-date { margin-top: 1.5rem; font: .65rem/1.8 system-ui, sans-serif; color: var(--muted); }
.leaf-card.is-back .leaf-front, .leaf-card:not(.is-back) .leaf-back { pointer-events: none; }

/* 信件：信纸可读状态与开封动作同步，换信不等待动画结束。 */
.letter-stage { min-height: 480px; background: #eae5d9; border-radius: 48% 48% 4px 4px; display: flex; align-items: flex-end; justify-content: center; padding: 3rem 2rem; perspective: 1200px; }
.envelope { position: relative; width: min(100%, 350px); height: 225px; clip-path: inset(-230px -10px 0 -10px); }
.envelope-back { position: absolute; inset: 0; background: #c9c3a9; border: 1px solid #beb99f; border-radius: 2px; }
.letter-paper { position: absolute; z-index: 1; width: 88%; height: 274px; left: 6%; bottom: 12px; background: #fbf9ee; padding: 1.5rem 1.4rem; box-shadow: 0 0 9px #6c705413; transform: translateY(86px); }
.letter-paper .letter-number { color: var(--muted); font-size: .57rem; letter-spacing: .12em; }
.letter-paper h2 { font: 400 1.1rem/1.5 var(--serif); margin: .8rem 0; }
.letter-paper p { font: .85rem/2 var(--serif); }
.letter-paper .letter-sign { font: .64rem/1.6 system-ui, sans-serif; margin-top: .8rem; color: var(--muted); text-align: right; }
.envelope-pocket { position: absolute; z-index: 2; inset: 0; background: linear-gradient(154deg, #dfd8be 49.8%, #d1cab0 50.2%, #ddd5b9 51%); clip-path: polygon(0 0, 50% 48%, 100% 0, 100% 100%, 0 100%); border-radius: 2px; }
.envelope-flap { position: absolute; z-index: 3; inset: 0; height: 54%; background: #d7cfb2; clip-path: polygon(0 0, 100% 0, 50% 100%); transform-origin: 50% 0; }
.envelope-label { position: absolute; z-index: 3; bottom: 1.6rem; left: 1.7rem; font: .9rem/1.5 var(--serif); letter-spacing: .1em; }
.envelope-stamp { position: absolute; z-index: 3; width: 2rem; height: 2rem; border: 1px solid #9b7660; bottom: 1.4rem; right: 1.7rem; color: #9b7660; font: .67rem/1.3 var(--serif); text-align: center; padding: .1rem; transform: rotate(-7deg); }
.letter-fallback { padding: 1.4rem; border: 1px solid var(--line); margin: 1rem 0; }
.letter-fallback summary { cursor: pointer; min-height: 44px; display: flex; align-items: center; font-family: var(--serif); }
.letter-fallback p { font-size: .8rem; line-height: 2; }

@media (hover: hover) and (pointer: fine) {
  .chapter-link:hover .arrow { transform: translate(3px, -3px); }
  .chapter-link:hover h3, .note-destination:hover { color: #6a8056; }
  .pill:hover { border-color: #7b8c6e; }
  .chime:hover .chime-name { color: #647849; }
}
@media (min-width: 1400px) { .chapter-hero { gap: 8%; } }
@media (max-width: 800px) {
  .chapter-hero { grid-template-columns: 1fr; padding: 2.5rem 0 2.8rem; gap: 2rem; }
  .chapter-copy { padding-left: 0; }
  .chapter-copy h1 { margin: 1rem 0; }
  .chapter-copy h1 span { display: inline; }
  .chapter-intro br { display: none; }
  .chapter-description { margin-top: .7rem; }
  .margin-note { margin-top: 1.2rem; }
  .exhibit { width: 100%; max-width: 540px; margin: auto; }
  .field-entry { grid-template-columns: 1fr; gap: 1.5rem; padding: 2.5rem 0; }
  .entry-meta { flex-direction: row; flex-wrap: wrap; gap: .5rem 1.4rem; }
  .entry-meta h2 { width: 100%; }
  .chapter-nav { gap: .3rem 1.5rem; }
}
@media (max-width: 520px) {
  .site-header { gap: .5rem; }
  .site-header .brand { font-size: 1rem; }
  .site-header nav { gap: .9rem; font-size: .7rem; }
  .return-link { font-size: .68rem; }
  .chapter-list { grid-template-columns: 1fr; }
  .chapter-link, .chapter-link:nth-child(even) { padding: 1.5rem .2rem; gap: .9rem; }
  .chapter-link h3 { font-size: 1.2rem; }
  .wander { padding: 1.5rem 0 3rem; }
  .wander .section-heading { margin-bottom: 1.5rem; }
  .chapter-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 0 1rem; }
  .chapter-nav a { justify-content: center; font-size: .68rem; }
  .chapter-copy h1 { font-size: clamp(2rem, 8.2vw, 2.7rem); }
  .chapter-intro { font-size: 1rem; }
  .chapter-description { font-size: .75rem; }
  .stage-marker { right: .8rem; font-size: .65rem; }
  .wind-stage { min-height: 360px; }
  .wind-bells { padding-top: 42px; gap: 4%; }
  .chime-art { height: 224px; }
  .chime:nth-child(2) .chime-art { height: 248px; }
  .chime:nth-child(3) .chime-art { height: 214px; }
  .chime-name { font-size: .8rem; }
  .cloud-stage { min-height: 355px; }
  .cloud { width: 110px; height: 88px; }
  .cloud-track { left: 8%; right: 8%; }
  .cloud-stations { left: 10%; right: 10%; }
  .leaf-stage { min-height: 400px; padding: 1.4rem; }
  .leaf-card { height: 340px; }
  .leaf-art { height: 219px; }
  .leaf-face { padding: 1.2rem; }
  .letter-stage { min-height: 520px; padding: 2.4rem 1.2rem; }
  .letter-paper { padding: 1.2rem 1rem; }
  .letter-paper p { font-size: .77rem; }
  .letter-paper h2 { font-size: 1rem; }
  .letter-paper .letter-sign { font-size: .57rem; }
  .pill { padding: .55rem .9rem; font-size: .7rem; }
  .next-stop { gap: 1rem; }
  .next-stop a { font-size: 1.1rem; gap: 1rem; }
}
@media (prefers-reduced-motion: reduce) {
  .chapter-link .arrow { transition: none; }
  .leaf-card-inner { transform: none !important; }
  .leaf-back { transform: none; }
  .leaf-card.is-back .leaf-front, .leaf-card:not(.is-back) .leaf-back { visibility: hidden; }
}
@media (prefers-reduced-transparency: reduce) {
  .pill { background: #fafbf4; }
  .pill[aria-pressed="true"], .pill.primary { background: #405745; }
}
@media (prefers-contrast: more) {
  :root { --muted: #42503f; --line: #76856d; }
  .pill, .leaf-face { border-color: #566c4b; }
  .stage::after { border-color: #76856d; }
}