/* ==========================================================================
   美呀美 · 导航升级与动效层 v1
   Mega 面板 / 行业索引 / 细分类弹层 / 跑马灯 / 光标 / 磁吸 / 回顶环 / 页面切换
   依赖 u.css 的令牌;所有动画仅用 transform / opacity / translate / scale
   ========================================================================== */

/* ---------- 1. 主导航:悬停下划线 + 当前页 ---------- */
.u-nav > ul > li > a { position: relative; }
.u-nav > ul > li > a::before {
  content: ""; position: absolute; left: .85rem; right: .85rem; bottom: .1rem; height: 1px;
  background: var(--accent); transform: scaleX(0); transform-origin: left center;
  transition: transform .55s var(--ease-out);
}
.u-nav > ul > li > a:hover::before,
.u-nav > ul > li.is-open > a::before,
.u-nav > ul > li > a.is-current::before { transform: scaleX(1); }
.u-nav > ul > li.is-open > a,
.u-nav > ul > li > a.is-current { color: var(--text); }
.u-nav__find { display: none; }
@media (min-width: 961px) {
  .u-nav li.has-mega .u-sub { display: none; }            /* 有 Mega 面板的项,不再弹出旧的小下拉 */
  .u-nav li.has-mega > a::after { display: none; }
}
.u-nav a.is-current { font-weight: 600; }

/* ---------- 2. 顶栏与遮罩 ---------- */
.u-header.is-mega { border-bottom-color: var(--line); }
.u-scrim {
  position: fixed; inset: 0; z-index: 99; background: rgba(12, 9, 8, .66);
  opacity: 0; visibility: hidden;
  transition: opacity .4s var(--ease), visibility 0s .4s;
}
.u-scrim.is-on { opacity: 1; visibility: visible; transition-delay: 0s; }

/* ---------- 3. Mega 面板 ---------- */
.u-megas { position: absolute; left: 0; right: 0; top: 100%; pointer-events: none; }
.u-mega {
  position: absolute; left: 0; right: 0; top: 0; pointer-events: auto;
  background: var(--bg); border-bottom: 1px solid var(--line);
  clip-path: inset(0 0 100% 0); opacity: 0; visibility: hidden;
  transition: clip-path .6s var(--ease-out), opacity .25s var(--ease), visibility 0s .6s;
}
.u-mega.is-open { clip-path: inset(0 0 0 0); opacity: 1; visibility: visible; transition-delay: 0s; }

.u-mega__in {
  display: grid; grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); gap: clamp(2rem, 4vw, 4rem);
  padding-block: 2rem 2.25rem; max-height: min(84vh, 46rem);
}
.u-mega__h { font-size: var(--t-xs); letter-spacing: .14em; color: var(--text-3); font-weight: 600; margin-bottom: .85rem; }

/* 左:行业列表 */
.u-mega__nav { min-height: 0; overflow-y: auto; padding-right: 1rem; scrollbar-width: thin; scrollbar-color: var(--line) transparent; overscroll-behavior: contain; }
.u-mega__list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 1.75rem; counter-reset: mg; border-top: 1px solid var(--line); }
.u-mega__list > li { border-bottom: 1px solid var(--line); min-width: 0; }
.u-mega__item { counter-increment: mg; }
.u-mega__a {
  display: flex; align-items: baseline; gap: .7rem; padding: .5rem 0; line-height: 1.5; color: var(--text-2); font-size: var(--t-sm);
  transition: color .3s var(--ease), padding-left .5s var(--ease-out);
}
.u-mega__a i { flex: none; min-width: 1.7rem; font: italic 1rem/1 var(--font-serif); color: var(--text-3); transition: color .3s var(--ease); }
.u-mega__item .u-mega__a i::before { content: counter(mg, decimal-leading-zero); }
.u-mega__a.is-all i::before { content: "∗"; font-style: normal; }
.u-mega__a span { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.u-mega__a em { margin-left: auto; flex: none; font-style: normal; font-size: var(--t-xs); color: var(--text-3); font-variant-numeric: tabular-nums; }
.u-mega__a:hover, .u-mega__a.is-active { color: var(--text); padding-left: .45rem; }
.u-mega__a:hover i, .u-mega__a.is-active i { color: var(--accent); }
.u-mega__a.is-active { font-weight: 600; }
.u-mega__list > li:first-child { grid-column: 1 / -1; }
.u-mega__nav.is-scroll { -webkit-mask-image: linear-gradient(180deg, #000 calc(100% - 2.5rem), transparent); mask-image: linear-gradient(180deg, #000 calc(100% - 2.5rem), transparent); }
.u-mega__nav.is-scroll.is-end { -webkit-mask-image: none; mask-image: none; }

/* 右:舞台 */
.u-mega__stage {
  min-width: 0; min-height: 0; display: flex; flex-direction: column; gap: 1.15rem; overflow-y: auto;
  border-left: 1px solid var(--line); padding-left: clamp(1.5rem, 3vw, 3rem); scrollbar-width: none;
}
.u-mega__stage::-webkit-scrollbar { display: none; }
.u-mega__top { display: flex; align-items: flex-end; justify-content: space-between; gap: 1.25rem; }
.u-mega__title { font-size: clamp(1.5rem, 2.4vw, 2.25rem); font-weight: 800; letter-spacing: -.02em; line-height: 1.15; }
.u-mega__sub { margin-top: .4rem; font-size: var(--t-xs); color: var(--text-3); letter-spacing: .06em; font-variant-numeric: tabular-nums; }
.u-mega__kidswrap { display: flex; flex-wrap: wrap; align-items: center; gap: .5rem; }
.u-mega__kidslabel { font-size: var(--t-xs); color: var(--text-3); margin-right: .25rem; }
.u-mega__prev { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1rem; }
.u-mega__empty { grid-column: 1 / -1; color: var(--text-3); font-size: var(--t-sm); padding: 1.25rem 0; }
.u-mega__stage.is-swap .u-mega__top, .u-mega__stage.is-swap .u-mega__kidswrap { animation: u-rise .5s var(--ease-out) both; }

/* 预览卡 */
.u-mprev { display: block; min-width: 0; animation: u-rise .7s var(--ease-out) both; animation-delay: calc(var(--i, 0) * 70ms); }
.u-mprev__win { display: block; border: 1px solid var(--line); border-radius: var(--r); background: var(--s1); overflow: hidden; transition: transform .6s var(--ease-out), border-color .35s var(--ease); }
.u-mprev__bar { display: flex; align-items: center; gap: .3rem; height: 1.1rem; padding: 0 .55rem; border-bottom: 1px solid var(--line); background: var(--s2); }
.u-mprev__bar i { width: .32rem; height: .32rem; border-radius: 50%; background: var(--line); }
.u-mprev__shot { display: block; aspect-ratio: 16 / 10; overflow: hidden; background: var(--s1); }
.u-mprev__shot img { width: 100%; height: 100%; object-fit: cover; object-position: top center; transition: transform .8s var(--ease-out); }
.u-mprev__t { display: block; margin-top: .55rem; font-size: var(--t-xs); color: var(--text-2); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; transition: color .3s var(--ease); }
@media (hover: hover) {
  .u-mprev:hover .u-mprev__win { transform: translateY(-4px); border-color: var(--text-3); }
  .u-mprev:hover .u-mprev__shot img { transform: scale(1.05); }
  .u-mprev:hover .u-mprev__t { color: var(--text); }
}
.u-mprev.is-skel .u-mprev__shot { background: linear-gradient(90deg, var(--s1) 20%, var(--s2) 50%, var(--s1) 80%); background-size: 220% 100%; animation: u-shimmer 1.3s linear infinite; }
.u-mprev.is-skel .u-mprev__t { height: .75rem; width: 60%; margin-top: .65rem; background: var(--s2); border-radius: 3px; }

@keyframes u-rise { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: none; } }
@keyframes u-shimmer { from { background-position: 120% 0; } to { background-position: -120% 0; } }

/* 手机 / 小程序:一排预览 */
.u-mega--row .u-mega__in { grid-template-columns: minmax(0, 3fr) minmax(0, 9fr); align-items: center; }
.u-mega__intro { display: flex; flex-direction: column; align-items: flex-start; gap: 1rem; }
.u-mega__row { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 1rem; align-items: start; }
.u-mphone { display: block; min-width: 0; }
.u-mphone__shot { display: block; overflow: hidden; border: 1px solid var(--line); border-radius: 12px; background: var(--s1); aspect-ratio: 330 / 622; transition: transform .6s var(--ease-out), border-color .35s var(--ease); }
.u-mega__row--qr .u-mphone__shot { aspect-ratio: 1; background: var(--paper); padding: .5rem; border-radius: 12px; }
.u-mphone__shot img { width: 100%; height: 100%; object-fit: cover; object-position: top center; opacity: 0; transition: opacity .5s var(--ease), transform .8s var(--ease-out); }
.u-mega__row--qr .u-mphone__shot img { object-fit: contain; }
.u-mphone__shot img.is-ready { opacity: 1; }
.u-mphone b { display: block; margin-top: .55rem; font-weight: 500; font-size: var(--t-xs); color: var(--text-2); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.u-mega.is-open .u-mphone { animation: u-rise .7s var(--ease-out) both; animation-delay: calc(var(--i, 0) * 60ms + 120ms); }
@media (hover: hover) {
  .u-mphone:hover .u-mphone__shot { transform: translateY(-5px); border-color: var(--text-3); }
  .u-mphone:hover .u-mphone__shot img { transform: scale(1.04); }
  .u-mphone:hover b { color: var(--text); }
}

/* ---------- 4. 「找案例」面板:行业 + 细分类 ---------- */
.u-industry { grid-template-columns: repeat(auto-fill, minmax(18rem, 1fr)); gap: 0 2.5rem; counter-reset: ind; }
.u-ind { counter-increment: ind; padding: 1rem 0 1.1rem; border-bottom: 1px solid var(--line); }
.u-ind__main { display: flex; align-items: baseline; gap: .9rem; font-weight: 600; transition: color .3s var(--ease), padding-left .5s var(--ease-out); }
.u-ind__main::before { content: counter(ind, decimal-leading-zero); font: italic 1.05rem/1 var(--font-serif); color: var(--text-3); min-width: 1.6rem; }
.u-ind__main em { margin-left: auto; font-style: normal; font-weight: 400; font-size: var(--t-xs); color: var(--text-3); font-variant-numeric: tabular-nums; }
.u-ind__main:hover { color: var(--accent); padding-left: .5rem; }
.u-ind__kids { display: flex; flex-wrap: wrap; gap: .4rem; margin: .8rem 0 0 2.5rem; }

/* ---------- 5. 首页行业条:细分类弹层 ---------- */
.u-chip.has-kids::after { content: ""; width: .32em; height: .32em; margin-left: .55em; border-right: 1px solid currentColor; border-bottom: 1px solid currentColor; transform: translateY(-.15em) rotate(45deg); opacity: .6; }
.u-pop {
  position: fixed; z-index: 60; min-width: 12rem; max-width: 22rem; padding: .5rem;
  background: var(--s2); border: 1px solid var(--line); border-radius: 12px;
  opacity: 0; visibility: hidden; transform: translateY(8px) scale(.98); transform-origin: top left;
  transition: opacity .25s var(--ease), transform .5s var(--ease-out), visibility 0s .25s;
}
.u-pop.is-open { opacity: 1; visibility: visible; transform: none; transition-delay: 0s; }
.u-pop__h { padding: .4rem .75rem .3rem; font-size: var(--t-xs); letter-spacing: .1em; color: var(--text-3); }
.u-pop a { display: block; padding: .5rem .75rem; border-radius: 8px; font-size: var(--t-sm); color: var(--text-2); transition: background-color .25s var(--ease), color .25s var(--ease); }
.u-pop a:hover, .u-pop a:focus-visible { background: var(--s1); color: var(--text); }

/* ---------- 6. 列表页侧栏:细分类高亮 + 展开/收起 ---------- */
.u-side__row { display: flex; align-items: stretch; }
.u-side__row > a { flex: 1; min-width: 0; }
.u-side__tog { flex: none; width: 2.25rem; display: grid; place-items: center; color: var(--text-3); border-left: 1px solid var(--line); transition: color .3s var(--ease); }
.u-side__tog:hover { color: var(--text); }
.u-side__tog i { width: .5rem; height: .5rem; border-right: 1.5px solid currentColor; border-bottom: 1.5px solid currentColor; transform: translateY(-.1rem) rotate(45deg); transition: transform .45s var(--ease-out); }
.u-side__tog[aria-expanded="true"] i { transform: translateY(.1rem) rotate(-135deg); }
.u-side__sub[hidden] { display: none !important; }
.u-side__sub { animation: u-rise .45s var(--ease-out) both; }
.u-side .u-side__sub a.is-current { color: var(--text); border-left: 2px solid var(--accent); font-weight: 600; }

/* ---------- 7. 行业名跑马灯 ---------- */
.u-mq { overflow: hidden; border-block: 1px solid var(--line); padding-block: clamp(1rem, 2.2vw, 1.75rem); user-select: none; }
.u-mq__track { display: flex; width: max-content; }
.js .u-mq__track { animation: u-mq 90s linear infinite; }
.u-mq:hover .u-mq__track { animation-play-state: paused; }
.u-mq span { display: flex; align-items: center; font-size: clamp(2rem, 5vw, 4.25rem); font-weight: 800; letter-spacing: -.02em; line-height: 1.15; color: transparent; -webkit-text-stroke: 1px var(--text-3); white-space: nowrap; transition: color .4s var(--ease); }
.u-mq span:hover { color: var(--text); -webkit-text-stroke-color: var(--text); }
.u-mq span::after { content: ""; flex: none; width: .5rem; height: .5rem; margin: 0 clamp(1.25rem, 3vw, 2.75rem); border-radius: 50%; background: var(--accent); }
@keyframes u-mq { to { transform: translateX(-50%); } }

/* ---------- 8. 主视觉:漂浮 ---------- */
.u-hero__stack .u-win:nth-child(1) { animation: u-float 9s ease-in-out infinite; }
.u-hero__stack .u-win:nth-child(2) { animation: u-float 11s ease-in-out -3s infinite reverse; }
.u-hero__stack .u-win:nth-child(3) { animation: u-float 10s ease-in-out -5s infinite; }
@keyframes u-float { 0%, 100% { translate: 0 0; } 50% { translate: 0 -10px; } }

/* ---------- 9. 光标跟随标签 ---------- */
.u-cursor {
  position: fixed; left: 0; top: 0; z-index: 400; pointer-events: none;
  width: 5rem; height: 5rem; margin: -2.5rem 0 0 -2.5rem; border-radius: 50%;
  display: grid; place-items: center; background: var(--accent); color: var(--accent-ink);
  font-size: var(--t-xs); font-weight: 700; letter-spacing: .08em;
  opacity: 0; scale: .35; translate: var(--cx, -100px) var(--cy, -100px);
  transition: opacity .2s var(--ease), scale .45s var(--ease-out);
}
.u-cursor.is-on { opacity: 1; scale: 1; }
html.has-cursor .u-win__tag { display: none; }

/* ---------- 10. 磁吸按钮 ---------- */
.u-btn { transition: background-color .35s var(--ease), color .35s var(--ease), border-color .35s var(--ease), transform .35s var(--ease), translate .45s var(--ease-out); }
.u-btn[data-mag] { translate: var(--tx, 0px) var(--ty, 0px); }

/* ---------- 11. 回到顶部 + 阅读进度环 ---------- */
.u-top {
  position: fixed; left: var(--gutter); bottom: 1.25rem; z-index: 90; width: 3rem; height: 3rem; border-radius: 50%;
  display: grid; place-items: center; background: var(--s1); color: var(--text);
  opacity: 0; visibility: hidden; transform: translateY(10px);
  transition: opacity .35s var(--ease), transform .5s var(--ease-out), visibility 0s .35s, background-color .3s var(--ease);
}
.u-top.is-on { opacity: 1; visibility: visible; transform: none; transition-delay: 0s; }
.u-top:hover { background: var(--s2); }
.u-top svg { position: absolute; inset: 0; width: 100%; height: 100%; transform: rotate(-90deg); }
.u-top circle { fill: none; stroke-width: 2; }
.u-top .bg { stroke: var(--line); }
.u-top .fg { stroke: var(--accent); stroke-linecap: round; stroke-dasharray: 125.66; stroke-dashoffset: 125.66; }
.u-top span { position: relative; font-size: 1.05rem; line-height: 1; }

/* ---------- 12. 页面切换(支持的浏览器) ---------- */
@view-transition { navigation: auto; }
.u-header { view-transition-name: u-header; }
::view-transition-old(root) { animation: u-vt-out .22s var(--ease) both; }
::view-transition-new(root) { animation: u-vt-in .55s var(--ease-out) both; }
@keyframes u-vt-out { to { opacity: 0; } }
@keyframes u-vt-in { from { opacity: 0; transform: translateY(12px); } }

/* ---------- 13. 响应式 ---------- */
@media (max-width: 1200px) {
  .u-mega__row { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .u-mega--row .u-mega__in { max-height: none; }
}
@media (max-width: 960px) {
  .u-side__tog { display: none; }
  .u-side__row { display: contents; }
  .u-side__row > a { flex: none; min-width: auto; }   /* 手机端是横向胶囊,链接不能被压缩 */
  .u-megas, .u-scrim { display: none; }
  .u-nav__find { display: block; padding: 0 0 1rem; }
  .u-nav__find .u-btn { width: 100%; }
  .u-nav > ul > li > a::before { display: none; }
  .u-industry { grid-template-columns: 1fr; }
  .u-top { bottom: 5.75rem; }
}
@media (max-width: 600px) {
  .u-top { width: 2.75rem; height: 2.75rem; }
}
@media (hover: none) { .u-cursor { display: none; } }

/* ---------- 14. 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  @view-transition { navigation: none; }
  .u-mq__track { animation: none !important; overflow-x: auto; }
  .u-mega { clip-path: none; }
  .u-cursor { display: none; }
}