/* ==========================================================================
   LINMO — 3D Character IP Showcase
   assets/css/style.css

   目录：
   01 设计变量与基础重置
   02 加载页（极简进度条）
   03 全屏画布与滚动内容层叠关系
   04 顶部导航（滚动隐藏）+ 移动端菜单
   05 左侧章节编号栏
   06 信息标签（半透明黑底白字 · 从模型旁淡入弹出）
   07 开场文案 / 收尾页脚 / 滚动提示 / 拖拽提示
   08 响应式与减弱动效偏好
========================================================================== */

/* ---------- 01 设计变量与基础重置 ---------- */
:root {
  --paper: #080a10;              /* 深夜黑背景 */
  --ink: #edf2ff;                /* 冷白主文字色 */
  --ink-60: rgba(237, 242, 255, .62);
  --ink-40: rgba(237, 242, 255, .42);
  --ink-10: rgba(237, 242, 255, .14);

  /* 信息标签专属：半透明黑底白字 */
  --tag-bg: rgba(14, 14, 14, .74);
  --tag-line: rgba(255, 255, 255, .08);
  --tag-dim: rgba(255, 255, 255, .58);

  --ease: cubic-bezier(.22, .61, .36, 1);
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --display: "Bodoni 72", Didot, "Times New Roman", "Noto Serif SC", "Songti SC", serif;
  --sans-display: "Avenir Next", "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;

  /* 层叠次序：画布(1) < 内容流(10) < 标签(20) < 编号栏/导航(30+) */
  --z-canvas: 1;
  --z-flow: 10;
  --z-tags: 20;
  --z-chrome: 30;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "Helvetica Neue", Helvetica, Arial,
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  background:
    radial-gradient(ellipse at 58% 68%, rgba(54, 67, 112, .20), transparent 34%),
    radial-gradient(ellipse at 82% 18%, rgba(72, 91, 146, .10), transparent 28%),
    linear-gradient(180deg, #070910 0%, #0a0d17 58%, #111729 100%);
  color: var(--ink);
  overflow-x: hidden;
  color-scheme: dark;
  -webkit-font-smoothing: antialiased;
}

::selection { background: var(--ink); color: var(--paper); }

:focus-visible { outline: 1px solid var(--ink-40); outline-offset: 3px; }

/* 加载未完成前锁定滚动，避免视角错过第一幕 */
body.is-loading { overflow: hidden; height: 100dvh; }

a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }

/* ---------- 02 加载页 ---------- */
.loader {
  position: fixed; inset: 0; z-index: 100;
  display: flex; flex-direction: column; justify-content: center; align-items: center;
  gap: 26px;
  background: var(--paper);
  transition: opacity .8s var(--ease), visibility 0s linear .8s;
}
.loader-mark {
  font-size: 17px; font-weight: 700; letter-spacing: .42em; text-indent: .42em;
}
.loader-dot { font-size: 9px; vertical-align: super; letter-spacing: 0; }
.loader-track {
  width: 172px; height: 1px; background: var(--ink-10); overflow: hidden;
}
.loader-track i {
  display: block; height: 100%; background: var(--ink);
  transform: scaleX(0); transform-origin: left;
  transition: transform .35s var(--ease);
}
#loader-text {
  font-family: var(--mono); font-size: 9px; letter-spacing: .38em;
  color: var(--ink-40);
}
/* 完成态：整页淡出 */
body.is-done .loader {
  opacity: 0; visibility: hidden; pointer-events: none;
}

/* ---------- 03 全屏画布与内容层 ---------- */
#stage {
  position: fixed; inset: 0; z-index: var(--z-canvas);
  width: 100%; height: 100%;
  display: block;
  cursor: grab;
  touch-action: pan-y;            /* 移动端：竖向滑动交给页面滚动，横向留给我们旋转 */
}
#stage.is-grabbing { cursor: grabbing; }
#stage.is-touching { cursor: grabbing; }

#scroll-flow { position: relative; z-index: var(--z-flow); pointer-events: none; }

.flow { position: relative; min-height: 100svh; }

/* ---------- 04 顶部导航 ---------- */
.site-nav {
  position: fixed; inset-inline: 0; top: 0; z-index: var(--z-chrome);
  display: flex; justify-content: space-between; align-items: center;
  padding: 14px clamp(20px, 4vw, 46px);
  background: linear-gradient(180deg, rgba(8, 10, 16, .72), transparent);
  transition: transform .55s var(--ease);
}
.site-nav.nav--hidden { transform: translateY(-115%); }

.nav-logo { font-family: var(--sans-display); font-size: 15px; font-weight: 750; letter-spacing: .18em; }
.nav-logo::before { content: '◌'; display: inline-block; margin-right: 7px; color: #9eb5ff; font-size: 11px; vertical-align: 1px; }
.nav-logo span { font-size: 9px; vertical-align: super; }

.site-nav nav a,
.nav-mobile a {
  position: relative;
  font-family: var(--sans-display);
  font-size: 12px; letter-spacing: .24em; color: var(--ink-60);
  transition: color .3s;
  padding-bottom: 3px;
}
.site-nav nav a::after,
.nav-mobile a::after {
  content: ""; position: absolute; left: 0; bottom: 0;
  width: 100%; height: 1px; background: var(--ink);
  transform: scaleX(0); transform-origin: right;
  transition: transform .4s var(--ease);
}
.site-nav nav a:hover, .nav-mobile a:hover,
.site-nav nav a:focus-visible, .nav-mobile a:focus-visible,
.site-nav nav a:active, .nav-mobile a:active { color: var(--ink); }
.site-nav nav a:hover::after, .nav-mobile a:hover::after,
.site-nav nav a:focus-visible::after, .nav-mobile a:focus-visible::after,
.site-nav nav a:active::after, .nav-mobile a:active::after {
  transform: scaleX(1); transform-origin: left;
}
.site-nav nav a:active, .nav-mobile a:active { transform: translateY(1px); }

/* 移动端汉堡按钮（简化版导航） */
.nav-burger {
  display: grid; gap: 6px; padding: 8px;
}
.nav-burger span {
  width: 22px; height: 1px; background: var(--ink);
  transition: transform .4s var(--ease);
}
.nav-burger.open span:nth-child(1) { transform: translateY(3.5px) rotate(45deg); }
.nav-burger.open span:nth-child(2) { transform: translateY(-3.5px) rotate(-45deg); }

.nav-mobile {
  position: fixed; inset: 0 0 auto 0; z-index: calc(var(--z-chrome) - 1);
  background: rgba(8, 10, 16, .94);
  -webkit-backdrop-filter: blur(14px); backdrop-filter: blur(14px);
  padding: 92px clamp(24px, 6vw, 48px) 34px;
  opacity: 0; visibility: hidden; transform: translateY(-10px);
  transition: opacity .45s var(--ease), transform .45s var(--ease),
              visibility 0s linear .45s;
}
.nav-mobile.open {
  opacity: 1; visibility: visible; transform: translateY(0);
  transition-delay: 0s;
}
.nav-mobile ul { display: grid; }
.nav-mobile a {
  display: block; padding: 15px 0; font-size: 19px; letter-spacing: .1em;
  border-bottom: 1px solid var(--ink-10); color: var(--ink);
}
.nav-mobile a::after { display: none; }

/* ---------- 05 左侧章节编号栏 ---------- */
.chapter-rail {
  position: fixed; left: 26px; top: 50%; transform: translateY(-50%);
  z-index: var(--z-chrome);
}
.chapter-rail ol { display: grid; gap: 30px; }
.chapter-rail li {
  display: flex; align-items: center; gap: 9px;
  cursor: pointer; -webkit-tap-highlight-color: transparent;
}
.chapter-rail .no {
  font-family: var(--mono); font-size: 10px; letter-spacing: .18em;
  color: var(--ink-40); transition: color .35s;
}
.chapter-rail .bar {
  position: relative; width: 20px; height: 1px;
  background: var(--ink-10); overflow: hidden;
}
.chapter-rail .bar i {
  position: absolute; inset: 0; background: var(--ink);
  transform: scaleX(0); transform-origin: left;
  transition: transform .5s var(--ease);
}
.chapter-rail li:hover .no,
.chapter-rail li:focus-visible .no,
.chapter-rail li:active .no { color: var(--ink); }
.chapter-rail li:active { transform: translateX(3px); }
.chapter-rail li.on .no { color: var(--ink); }
.chapter-rail li.on .bar { width: 32px; }
.chapter-rail li.on .bar i { transform: scaleX(1); }
.chapter-rail .bar { transition: width .5s var(--ease); }

/* ---------- 06 信息标签 ---------- */
.tag-layer {
  position: fixed; inset: 0; z-index: var(--z-tags);
  pointer-events: none;           /* 只让标签自身可交互，其余穿透到画布 */
  overflow: hidden;
}
/* 外壳：纯定位层，transform 由 JS 每帧写入锚点屏幕坐标 */
.info-tag {
  position: absolute; left: 0; top: 0;
  width: min(78vw, 272px);
  will-change: transform;
}
/* 内层：承载全部视觉与弹出动画 */
.tag-inner {
  padding: 15px 17px 16px;
  background: linear-gradient(145deg, rgba(28, 34, 55, .78), rgba(8, 10, 16, .64));
  -webkit-backdrop-filter: blur(16px) saturate(1.2);
  backdrop-filter: blur(16px) saturate(1.2);
  border: 1px solid rgba(174, 193, 255, .18);
  box-shadow: 0 18px 48px rgba(0, 0, 0, .28), inset 0 1px rgba(255,255,255,.07);
  color: #fff;
  transform: translateY(15px) scale(.965);
  opacity: 0; filter: blur(7px);
  transition: opacity .55s var(--ease), transform .55s var(--ease),
              filter .55s var(--ease);
  will-change: transform, opacity, filter;
}
.info-tag.is-on .tag-inner {
  opacity: 1; filter: blur(0);
  transform: translateY(0) scale(1);
}
/* 可交互范围随内层展开（外层始终穿透） */
.info-tag.is-on { pointer-events: auto; }
.tag-index {
  font-family: var(--mono); font-size: 9px; letter-spacing: .4em;
  color: var(--tag-dim);
}
.tag-title {
  margin-top: 9px;
  font-size: 16px; font-weight: 600; letter-spacing: .3em;
}
.tag-body {
  margin-top: 9px;
  font-size: 12px; line-height: 1.85; letter-spacing: .04em;
  color: var(--tag-dim);
}
.tag-link {
  display: inline-block; margin-top: 11px;
  font-family: var(--mono); font-size: 11px; letter-spacing: .16em;
  border-bottom: 1px solid rgba(255, 255, 255, .35);
  padding-bottom: 2px;
  transition: border-color .3s;
}
.tag-link:hover { border-color: #fff; }

/* 画廊视觉板：无外部图片依赖的可用品牌卡片 */
.tag-gallery { width: min(84vw, 306px); }
.tag-grid { display: flex; gap: 7px; margin-top: 12px; }
.tag-grid .ph {
  flex: 1; aspect-ratio: 3 / 4; position: relative; overflow: hidden;
  display: flex; flex-direction: column; justify-content: space-between;
  padding: 9px 8px 8px; color: rgba(255,255,255,.72);
  border: 1px solid rgba(174, 193, 255, .18);
  background-color: #171923;
  box-shadow: inset 0 1px rgba(255,255,255,.08), 0 10px 24px rgba(0,0,0,.2);
}
.tag-grid .ph::after { content: ''; position: absolute; inset: 18% 20%; border: 1px solid rgba(255,255,255,.2); border-radius: 50%; transform: scaleX(.68); }
.tag-grid .ph b, .tag-grid .ph small { position: relative; z-index: 1; font-family: var(--mono); }
.tag-grid .ph b { font-size: 10px; letter-spacing: .12em; }
.tag-grid .ph small { font-size: 7px; letter-spacing: .12em; color: var(--tag-dim); }
.tag-grid .ph-front { background: radial-gradient(circle at 50% 42%, rgba(221,231,255,.34), transparent 24%), linear-gradient(145deg,#252a3a,#0c0d13 70%); }
.tag-grid .ph-side { background: radial-gradient(circle at 38% 55%, rgba(129,161,255,.32), transparent 22%), linear-gradient(210deg,#1d2535,#090a0f 68%); }
.tag-grid .ph-core { background: radial-gradient(circle at 50% 48%, rgba(255,211,145,.8), transparent 18%), linear-gradient(125deg,#34291f,#0d0d12 68%); }
.gallery-input { position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none; }
.tag-grid .ph-upload { cursor: pointer; border-style: dashed; border-color: rgba(190,205,255,.46); background: radial-gradient(circle, rgba(144,170,255,.18), transparent 60%), #111522; }
.tag-grid .ph-upload:hover { border-color: rgba(220,230,255,.85); transform: translateY(-2px); }

/* ---------- 07 开场 / 页脚 / 提示 ---------- */
.intro-copy {
  position: absolute; left: clamp(20px, 6vw, 86px); top: 50%;
  transform: translateY(-54%);
}
.intro-eyebrow {
  font-family: var(--mono); font-size: 9px; letter-spacing: .58em; text-transform: uppercase;
  color: var(--ink-40);
}
.intro-copy h1 {
  margin-top: 26px;
  font-family: var(--sans-display);
  font-size: clamp(46px, 8vw, 112px); line-height: .88;
  font-weight: 800; letter-spacing: -.065em;
  color: #ffffff;
  text-shadow:
    1px 1px 0 rgba(166, 181, 220, .72),
    2px 2px 0 rgba(112, 128, 174, .56),
    3px 3px 0 rgba(72, 86, 128, .42),
    4px 4px 0 rgba(37, 46, 76, .52),
    0 0 28px rgba(150, 170, 255, .16);
}
.intro-copy h1 em {
  display: block; margin-top: 20px;
  font-family: var(--display);
  font-style: italic; font-weight: 400;
  font-size: clamp(15px, 1.8vw, 22px); letter-spacing: .22em;
  color: #b9c5e7;
  text-shadow: 0 0 18px rgba(126, 157, 255, .18);
}
.intro-sub {
  margin-top: 30px;
  font-size: 12px; line-height: 2.05; letter-spacing: .13em;
  color: #9aa7c8;
  max-width: 27em;
}

.outro-foot {
  position: absolute; inset-inline: 0; bottom: 0;
  display: flex; justify-content: space-between; align-items: end;
  gap: 14px; flex-wrap: wrap;
  padding: 0 clamp(20px, 4vw, 46px) 26px;
  font-family: var(--mono); font-size: 9px; letter-spacing: .26em;
  color: var(--ink-40);
}

/* 底部滚动提示（开场专属） */
.scroll-cue {
  position: absolute; left: 50%; bottom: 30px; transform: translateX(-50%);
  display: grid; justify-items: center; gap: 12px;
  font-family: var(--mono); font-size: 9px; letter-spacing: .5em; text-indent: .5em;
  color: var(--ink-40);
}
.scroll-cue span {
  width: 1px; height: 44px; background: var(--ink-40);
  animation: cue-drop 2.4s var(--ease) infinite;
  transform-origin: top;
}
@keyframes cue-drop {
  0%   { transform: scaleY(0); }
  45%  { transform: scaleY(1); transform-origin: top; }
  46%  { transform-origin: bottom; }
  100% { transform: scaleY(0); transform-origin: bottom; }
}

/* 右下角交互提示：首次拖拽后由脚本淡出 */
.drag-hint {
  position: fixed; right: clamp(20px, 4vw, 46px); bottom: 28px; z-index: var(--z-chrome);
  display: flex; align-items: center; gap: 10px;
  font-family: var(--mono); font-size: 9px; letter-spacing: .32em;
  color: var(--ink-40);
  transition: opacity 1s var(--ease);
}
.hint-line { width: 26px; height: 1px; background: var(--ink-10); }
.drag-hint.is-hidden { opacity: 0; pointer-events: none; }

/* ---------- 08 响应式与动效偏好 ---------- */
@media (max-width: 700px) {
  .drag-hint { display: none; }
  .intro-copy { top: 42%; left: 18px; }
  .intro-copy h1 { font-size: clamp(42px, 14vw, 76px); }
  .intro-copy h1 em { font-size: 15px; letter-spacing: .16em; }
  .chapter-rail { left: 14px; }
  .chapter-rail ol { gap: 24px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .scroll-cue span { animation: none; }
  *, *::before, *::after {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}