/* ============================================================
   CSIG 正发声 · AI 的加速度 —— 封面首页
   分层校准结论（见 manifest.json 与 calibrate.py / calib-v2-left.png）：
   - 底册 archive-base.png     1192×1320，内容 bbox [0,20,1192,1306]
   - 封皮 archive-cover-v2.png  992×1080，内容 bbox [54,0,967,1080]
     （2026-09-11 换图：AI 研究线索图案 + 「AI 的加速度」题字已生成在封皮上）
   - 同一容器（1203×1320）内：底册 left:0 top:0；
     封皮按内容高度对齐（scale 1.1907）后内容左上角对齐 → left:-64px top:20px，
     右侧露出底册纸边与便签为预期效果（档案里夹着的纸条感）。
   ============================================================ */

:root {
  --ink-cream: #ece1c6;          /* 封面主文字（米白） */
  --ink-dim: rgba(207, 195, 166, .82);
  --tech: #426bcc;               /* 研究线蓝 */
  --warm: #ffd483;               /* 纸缝暖光 */
  --bg-fallback: #0b1220;        /* 背景图失败时的底色 */
  --paper-neutral: #eceae2;      /* 承接第一幕的中性打印纸色 */
  --paper-ink: #34322b;          /* 中性纸面上的墨色 */

  /* 档案设计坐标系（单位 px，按 --bs 整体缩放） */
  --book-w: 1203px;
  --book-h: 1320px;
  --bs: .5;                      /* 由 JS 取景计算 */
  --push: 2.35;                  /* 推近倍率，可在 CoverExperience.config 调 */
  --openDur: 1500ms;             /* 展开时长 1200–1800 可调 */

  /* 字体资产：@font-face、年代/角色 token 与手写 SVG 描边动画见 assets/fonts/fonts.css */
  --font-serif: "Noto Serif SC", "Songti SC", "STSong", "Noto Serif CJK SC", "SimSun", serif;
  --font-serif-la: "EB Garamond", "Noto Serif SC", "Songti SC", "STSong", serif;
  --font-sans: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html, body { height: 100%; }
html.cover-lock, html.cover-lock body { overflow: hidden; }

body {
  margin: 0;
  background: var(--bg-fallback);
  color: var(--ink-cream);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
}

button { font: inherit; -webkit-tap-highlight-color: transparent; }

/* ---------------- 封面根 ---------------- */
.coverRoot {
  position: fixed;
  inset: 0;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  z-index: 1;
}

/* 背景层：略放大以容纳视差位移 */
.bg {
  position: absolute;
  inset: -3.5%;
  z-index: 0;
  transition: filter var(--openDur) ease;
}
.bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  user-select: none;
}
.is-opening .bg { filter: brightness(.5) saturate(.85); }

/* ---------------- 顶栏：左品牌 / 右活动入口 ---------------- */
.topbar {
  position: relative;
  z-index: 3;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: max(16px, 2.8vh) clamp(18px, 3.5vw, 44px) 0;
  transition: opacity .3s ease;
}
.brand { flex: 0 0 auto; }
.brandLogo {
  display: block;
  height: clamp(44px, 6.5vh, 72px);
  width: auto;
  user-select: none;
  filter: drop-shadow(0 2px 10px rgba(0, 0, 0, .35));
}
@media (max-width: 480px) {
  .brandLogo { height: 44px; }
}
.topActions {
  display: flex;
  gap: clamp(8px, 1vw, 14px);
}
.topAction {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  cursor: pointer;
  border-radius: 8px;
}
.topAction img {
  display: block;
  height: clamp(52px, 7.2vh, 78px);
  width: auto;
  user-select: none;
  transition: transform .25s ease, filter .25s ease;
}
.topAction:hover img {
  transform: translateY(-2px);
  filter: brightness(1.07) drop-shadow(0 4px 14px rgba(255, 205, 120, .28));
}
.topAction:focus-visible {
  outline: 2px solid var(--warm);
  outline-offset: 4px;
}
.topAction:active img { transform: translateY(0); }
@media (max-width: 480px) {
  .topAction img { height: 50px; }
}


/* ---------------- 中央档案区 ---------------- */
.bookWrap {
  position: relative;
  z-index: 2;
  flex: 1 1 auto;
  min-height: 0;
  display: grid;
  place-items: center;
  overflow: hidden;
}

/* 延伸研究线：档案后方，加载完成后一次性绘出，之后静止 */
.researchLine {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  opacity: 0;
  transition: opacity .8s ease;
}
.researchLine path {
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
  transition: stroke-dashoffset 2.6s cubic-bezier(.4, 0, .2, 1) .45s;
}
.is-ready .researchLine { opacity: .34; }
.is-ready .researchLine path { stroke-dashoffset: 0; }
.is-opening .researchLine { opacity: 0; transition: opacity .3s ease; }

.bookPan {
  position: absolute;
  inset: 0;
  z-index: 2;
  will-change: transform;
}

/* 缩放层：设计坐标 1203×1320，transform-origin 对准内页焦点（推近锚点 61% 52%）。
   用 calc 补偿 origin 偏移，保证任意缩放档位下档案视觉中心始终在取景容器中心。 */
.bookScale {
  position: absolute;
  width: var(--book-w);
  height: var(--book-h);
  left: calc(50% - 733.83px + (132.33px * var(--bs)) - var(--shiftX, 0px));
  top: calc(50% - 686.4px + (26.4px * var(--bs)));
  transform: scale(var(--bs));
  transform-origin: 61% 52%;
  opacity: 0;
  transition: opacity .9s ease .15s;
}
.is-ready .bookScale { opacity: 1; }

.book {
  position: absolute;
  inset: 0;
  perspective: 1700px;
}

.book img { user-select: none; }

/* 底册（内页）：left:0 top:0 */
.bookBase {
  position: absolute;
  left: 0;
  top: 0;
  width: 1192px;
  height: 1320px;
}

/* 封皮层：校准位置 left:0 top:-7px；围绕左侧装订边（约自身 15.8% 处）转开 */
/* 封皮层 v2（2026-09-11 换图，带「AI 的加速度」题字）：
   原图 992×1080、内容 bbox [54,0,967,1080]；按内容高度对齐底册（scale 1.1907），
   内容左上角对齐 → left:-64px / top:20px；右侧露出底册纸边为预期效果。
   装订绳柱约在自身 9% 处，作为转开旋转轴。 */
.bookCover {
  position: absolute;
  left: -64px;
  top: 20px;
  width: 1181px;
  height: 1286px;
  transform-origin: 9% 50%;
  will-change: transform, opacity;
}
.bookCover > img {
  width: 100%;
  height: 100%;
  display: block;
}

/* 屏幕阅读器专用文本（封面题字已生成在封皮图内） */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* 纸缝暖光：对准右下角卷角，screen 混合 + 呼吸 */
.seamGlow {
  position: absolute;
  left: 650px;
  top: 636px;
  width: 680px;
  mix-blend-mode: screen;
  opacity: .3;
  pointer-events: none;
  animation: seamBreathe 4.8s ease-in-out infinite;
}
@keyframes seamBreathe {
  0%, 100% { opacity: .26; }
  50% { opacity: .46; }
}

/* 档案投影 */
.bookShadow {
  position: absolute;
  left: 12%;
  right: 12%;
  bottom: -64px;
  height: 130px;
  background: radial-gradient(ellipse at center, rgba(0, 0, 0, .5), transparent 68%);
  z-index: -1;
  transition: opacity .4s ease;
}

/* ---------------- 入口区 ---------------- */
.entryZone {
  position: relative;
  z-index: 3;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: clamp(10px, 1.8vh, 16px);
  padding-bottom: max(20px, 4.2vh);
  opacity: 0;
  transition: opacity .8s ease .4s;
}
.is-ready .entryZone { opacity: 1; }
.is-opening .entryZone {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity .28s ease, transform .28s ease;
  pointer-events: none;
}

/* 入口局部暖光：悬停/聚焦时增强 */
.entryGlow {
  position: absolute;
  left: 50%;
  bottom: -12px;
  width: min(420px, 70vw);
  height: 150px;
  transform: translateX(-50%);
  background: radial-gradient(ellipse at center, rgba(255, 205, 120, .42), transparent 68%);
  opacity: 0;
  transition: opacity .35s ease;
  pointer-events: none;
}

.entry {
  position: relative;
  border: 0;
  padding: 0;
  margin: 0;
  background: transparent;
  width: clamp(200px, 26vw, 300px);
  aspect-ratio: 2172 / 724;
  cursor: pointer;
  transition: transform .28s cubic-bezier(.34, 1.4, .5, 1);
}
.entryPaper {
  position: absolute;
  inset: -9% -5%; /* 纸片毛边略微溢出按钮盒 */
  width: 110%;
  height: 118%;
  user-select: none;
}
.entryLabel {
  position: relative;
  z-index: 1;
  display: inline-block;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(18px, 1.7vw, 23px);
  letter-spacing: .34em;
  text-indent: .34em;
  color: #43331d;
  transform: translateY(-4%);
}
.entry:hover, .entry:focus-visible { transform: translateY(-5px) rotate(-.4deg); }
.entryZone:has(.entry:hover) .entryGlow,
.entryZone:has(.entry:focus-visible) .entryGlow { opacity: 1; }
.entry:focus-visible {
  outline: 2px solid var(--warm);
  outline-offset: 7px;
  border-radius: 4px;
}
.entry:active { transform: translateY(-2px) scale(.985); }
.entry:disabled { cursor: default; }

/* ---------------- 揭开转场 ---------------- */
.neutralWipe {
  position: absolute;
  inset: 0;
  z-index: 4;
  background: linear-gradient(158deg, #f0ede5 0%, var(--paper-neutral) 46%, #e3e0d7 100%);
  opacity: 0;
  pointer-events: none;
}

.is-opening .bookCover {
  animation: coverOpen calc(var(--openDur) * .68) cubic-bezier(.45, .05, .25, 1) forwards;
}
@keyframes coverOpen {
  0%   { transform: rotateY(0deg) translateZ(0); opacity: 1; }
  35%  { transform: rotateY(-72deg) translateZ(70px); opacity: 1; }
  70%  { opacity: .55; }
  100% { transform: rotateY(-168deg) translateZ(40px); opacity: 0; }
}

.is-opening .bookScale {
  animation: pushIn var(--openDur) cubic-bezier(.55, .06, .25, 1) calc(var(--openDur) * .08) forwards;
}
@keyframes pushIn {
  from { transform: scale(var(--bs)); }
  to   { transform: scale(calc(var(--bs) * var(--push))); }
}

.is-opening .seamGlow {
  animation: seamFlare calc(var(--openDur) * .7) ease-out forwards;
}
@keyframes seamFlare {
  0%   { opacity: .34; }
  14%  { opacity: .8; }
  60%  { opacity: .42; }
  100% { opacity: 0; }
}

.is-opening .neutralWipe {
  animation: neutralIn var(--openDur) linear forwards;
}
@keyframes neutralIn {
  0%, 55% { opacity: 0; }
  100%    { opacity: 1; }
}

.is-opening .bookShadow { opacity: 0; }
.is-opening .topbar { opacity: 0; }

/* ---------------- 降级（主素材加载失败） ---------------- */
.fallbackCopy {
  display: none;
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 0 24px;
}
.fallbackCopy .title {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(38px, 8vw, 72px);
  letter-spacing: .08em;
  color: var(--ink-cream);
}
.fallbackCopy .subtitle {
  margin: 18px 0 0;
  font-family: var(--font-serif);
  font-size: clamp(16px, 3vw, 24px);
  letter-spacing: .14em;
  color: var(--ink-dim);
}
.degraded-book .bookScale { display: none; }
.degraded-book .researchLine { display: none; }
.degraded-book .fallbackCopy { display: block; }
.degraded-entry .entry {
  background: linear-gradient(160deg, #ead9b8, #d9c49a);
  border-radius: 8px;
  box-shadow: 0 8px 30px rgba(0, 0, 0, .35);
}
.degraded-entry .entryPaper { display: none; }

/* ---------------- 故事承接容器 ---------------- */
.storyRoot {
  position: relative;
  z-index: 2;
  min-height: 100dvh;
  background: var(--paper-neutral);
  color: var(--paper-ink);
  font-family: var(--font-sans);
  opacity: 0;
  transition: opacity .4s ease;
}
.storyRoot.is-live { opacity: 1; }

/* 中性打印纸上的浅格线（工作台描图纸感） */
.storyFallback {
  min-height: 100dvh;
  display: grid;
  place-items: center;
  padding: 48px 20px;
  background-image:
    linear-gradient(rgba(70, 90, 130, .07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(70, 90, 130, .07) 1px, transparent 1px);
  background-size: 44px 44px;
}

.paperCard {
  width: min(560px, 92vw);
  background: #fbfaf6;
  border: 1px solid #d6d3c8;
  border-radius: 4px;
  box-shadow: 0 18px 50px rgba(35, 40, 55, .12), 0 2px 6px rgba(35, 40, 55, .08);
  padding: clamp(28px, 5vw, 44px) clamp(24px, 5vw, 48px);
}
.cardTag {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: .32em;
  color: #8a867a;
}
.cardHeading {
  margin: 0 0 14px;
  font-family: var(--font-serif);
  font-size: clamp(22px, 3.4vw, 30px);
  letter-spacing: .04em;
  color: #2e2c25;
  outline: none;
}
.cardHeading:focus-visible { outline: 2px solid #2f5fd0; outline-offset: 6px; }
.cardText {
  margin: 0 0 12px;
  font-size: 14.5px;
  line-height: 1.9;
  color: #55524a;
}
.cardText code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 13px;
  background: #efede6;
  border: 1px solid #ddd9cd;
  border-radius: 3px;
  padding: 1px 6px;
}
.cardStatus {
  margin: 0 0 20px;
  min-height: 1.6em;
  font-size: 13px;
  color: #8a6d3b;
}
.cardActions { display: flex; gap: 12px; flex-wrap: wrap; }
.cardActions button {
  border-radius: 3px;
  padding: 10px 22px;
  font-size: 14px;
  letter-spacing: .08em;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}
.btnPrimary {
  border: 1px solid #2f5fd0;
  background: #2f5fd0;
  color: #f6f4ee;
}
.btnPrimary:hover { background: #2853b8; }
.btnGhost {
  border: 1px solid #b9b5a7;
  background: transparent;
  color: #4c4940;
}
.btnGhost:hover { background: #f0eee7; }
.cardActions button:focus-visible { outline: 2px solid #2f5fd0; outline-offset: 3px; }
.cardActions button:active { transform: translateY(1px); }

/* ---------------- 小高度横屏 ---------------- */
@media (max-height: 480px) {
  .topbar { padding-top: 8px; }
  .brandLogo { height: 30px; }
  .topAction img { height: 44px; }
  .entryZone { gap: 7px; padding-bottom: 12px; }
  .entry { width: clamp(150px, 22vw, 210px); }
  .entryLabel { font-size: 16px; }
}

/* ---------------- 减少动态效果 ---------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .seamGlow { animation: none; opacity: .3; }
  .researchLine path { transition: none; stroke-dashoffset: 0; }
  .is-ready .researchLine { transition: opacity .01s; }
  .bookScale, .entryZone { transition-duration: .01s; transition-delay: 0s; }

  /* 点击后不强迫观看动画：极短交叉淡入 */
  .is-opening .bookCover { animation: reduceFade var(--openDur) linear forwards; }
  .is-opening .bookScale { animation: none; }
  .is-opening .seamGlow { animation: none; opacity: 0; }
  @keyframes reduceFade { to { opacity: 0; } }
}