/* 拙壮程长科技培训学校 — 官网样式
   无构建步骤，直接由 lite-cms 的 front_dir 托管。 */

/* ---------------------------------------------------------- 设计令牌 */
:root {
  /* 主色取自校徽：深蓝骨架 + 青绿强调 + 暖金点缀 */
  --blue-900: #0d3a63;
  --blue-800: #16578f;
  --blue-700: #1d6aab;
  --blue-050: #e8f1fa;
  --teal-700: #1f6f66; /* 小字用：白底 6:1 */
  --teal-500: #2e9e8f; /* 大字/图标/描边：白底 3.3:1 */
  --teal-050: #e6f4f1;
  --gold-600: #b8791b; /* 小字用 */
  --gold-500: #e8a33d; /* 大色块/描边 */
  --gold-050: #fdf3e2;

  --ink: #14243a;
  --ink-2: #3d5068;
  --muted: #6b7c92;
  --line: #dbe4ee;
  --bg: #f5f8fc;
  --surface: #fff;

  --radius: 12px;
  --radius-lg: 20px;
  --shadow-sm: 0 1px 2px rgba(20, 36, 58, .06), 0 2px 8px rgba(20, 36, 58, .04);
  --shadow-md: 0 4px 12px rgba(20, 36, 58, .08), 0 12px 32px rgba(20, 36, 58, .06);
  --shadow-lg: 0 12px 28px rgba(13, 58, 99, .14), 0 32px 64px rgba(13, 58, 99, .10);

  --wrap: 1180px;
  --gutter: clamp(16px, 4vw, 32px);
  --section-y: clamp(56px, 8vw, 104px);

  --font: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-serif: "Songti SC", "STSong", "Source Han Serif SC", "Noto Serif SC", "SimSun", serif;
}

/* ---------------------------------------------------------- 复位 */
*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--blue-800); text-decoration: none; }
a:hover { color: var(--blue-700); text-decoration: underline; }
button { font: inherit; cursor: pointer; }
h1, h2, h3, h4 { line-height: 1.3; margin: 0 0 .6em; font-weight: 700; color: var(--ink); }
h1 { font-size: clamp(28px, 4.4vw, 46px); letter-spacing: -.01em; }
h2 { font-size: clamp(24px, 3.2vw, 34px); letter-spacing: -.01em; }
h3 { font-size: clamp(18px, 2vw, 22px); }
p { margin: 0 0 1em; }
ul, ol { margin: 0 0 1em; padding-left: 1.4em; }
li { margin-bottom: .4em; }

:focus-visible { outline: 3px solid var(--blue-700); outline-offset: 2px; border-radius: 4px; }

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--blue-800); color: #fff; padding: 10px 16px; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ---------------------------------------------------------- 版面 */
.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }

.section { padding: var(--section-y) 0; }
.section--tint { background: #fff; }
.section--blue { background: var(--blue-900); color: #dce7f2; }
.section--blue h2, .section--blue h3 { color: #fff; }
.section--blue .eyebrow { color: #7fd3c6; }
.section--blue .lede { color: #b9cbe0; }

.section-head { max-width: 760px; margin-bottom: clamp(28px, 4vw, 52px); }
.section-head--center { margin-inline: auto; text-align: center; }

.eyebrow {
  display: block; font-size: 13px; font-weight: 700; letter-spacing: .18em;
  text-transform: uppercase; color: var(--teal-700); margin-bottom: 10px;
}
.lede { font-size: clamp(15px, 1.6vw, 17px); color: var(--ink-2); }

.grid { display: grid; gap: clamp(16px, 2.4vw, 26px); }
.grid--2 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 320px), 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 290px), 1fr)); }
.grid > * { min-width: 0; }

/* ---------------------------------------------------------- 内页页头 */
.page-head {
  background: linear-gradient(135deg, var(--blue-900) 0%, var(--blue-800) 100%);
  color: #fff; padding: clamp(38px, 5.5vw, 68px) 0 clamp(34px, 4.5vw, 56px);
}
.page-head h1 { color: #fff; margin-bottom: .35em; }
.page-head p { color: #c6d8e9; max-width: 68ch; margin: 0; }
.crumb { font-size: 13px; color: #9fc0dd; margin-bottom: 14px; }
.crumb a { color: #cfe0ef; }
.crumb a:hover { color: #fff; }

/* ---------------------------------------------------------- 页头 */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.site-header__inner {
  display: flex; align-items: center; gap: 20px;
  min-height: 68px; max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter);
}

.brand { display: flex; align-items: center; gap: 12px; color: var(--ink); text-decoration: none; flex: none; }
.brand:hover { text-decoration: none; color: var(--ink); }
.brand__text { display: flex; flex-direction: column; line-height: 1.15; }
.brand__name { font-size: 19px; font-weight: 700; letter-spacing: .06em; }
.brand__sub { font-size: 10px; letter-spacing: .16em; color: var(--muted); text-transform: uppercase; }
.brand__logo { height: 46px; width: auto; flex: none; }

.nav { margin-left: auto; }
.nav__list { display: flex; align-items: center; gap: 4px; list-style: none; margin: 0; padding: 0; }
.nav__list li { margin: 0; }
.nav__link {
  display: block; padding: 8px 14px; border-radius: 8px; font-size: 15px;
  color: var(--ink-2); white-space: nowrap;
}
.nav__link:hover { background: var(--blue-050); color: var(--blue-800); text-decoration: none; }
.nav__link[aria-current="page"] { color: var(--blue-800); font-weight: 700; background: var(--blue-050); }

.nav-toggle {
  display: none; margin-left: auto; width: 44px; height: 44px;
  border: 1px solid var(--line); border-radius: 10px; background: #fff;
  align-items: center; justify-content: center;
}
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after {
  content: ""; display: block; width: 20px; height: 2px; background: var(--ink); border-radius: 2px;
  position: relative; transition: transform .2s;
}
.nav-toggle span::before { position: absolute; top: -6px; }
.nav-toggle span::after { position: absolute; top: 6px; }

@media (max-width: 900px) {
  .nav-toggle { display: flex; }
  .nav {
    position: fixed; inset: 68px 0 auto; margin: 0;
    background: #fff; border-bottom: 1px solid var(--line);
    padding: 8px var(--gutter) 20px;
    transform: translateY(-120%); transition: transform .25s ease;
    box-shadow: var(--shadow-md);
  }
  .nav[data-open="true"] { transform: translateY(0); }
  .nav__list { flex-direction: column; align-items: stretch; gap: 2px; }
  .nav__link { padding: 13px 12px; font-size: 16px; border-radius: 8px; }
  .nav__cta { margin-top: 10px; }
  .nav__cta .btn { width: 100%; }
}

/* ---------------------------------------------------------- 按钮 */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 12px 24px; border: 1px solid transparent; border-radius: 10px;
  font-size: 15px; font-weight: 600; line-height: 1; text-align: center;
  transition: transform .15s, box-shadow .15s, background .15s;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn:active { transform: translateY(0); }

.btn--primary { background: var(--blue-800); color: #fff; box-shadow: var(--shadow-sm); }
.btn--primary:hover { background: var(--blue-700); color: #fff; box-shadow: var(--shadow-md); }

.btn--gold { background: var(--gold-500); color: #3a2a08; box-shadow: var(--shadow-sm); }
.btn--gold:hover { background: #f0b158; color: #3a2a08; box-shadow: var(--shadow-md); }

.btn--ghost { background: transparent; color: var(--blue-800); border-color: var(--line); }
.btn--ghost:hover { background: var(--blue-050); color: var(--blue-800); border-color: var(--blue-050); }

.btn--onDark { background: rgba(255, 255, 255, .12); color: #fff; border-color: rgba(255, 255, 255, .35); }
.btn--onDark:hover { background: rgba(255, 255, 255, .2); color: #fff; }

.btn--sm { padding: 9px 16px; font-size: 14px; }
.btn[disabled] { opacity: .55; pointer-events: none; }

/* ---------------------------------------------------------- 卡片 */
.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: clamp(20px, 2.4vw, 28px); box-shadow: var(--shadow-sm);
  transition: transform .18s, box-shadow .18s, border-color .18s;
  display: flex; flex-direction: column;
}
.card--hover:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: #c9d8ea; }
.card__title { margin-bottom: 8px; }
.card p:last-child { margin-bottom: 0; }
.card__meta { font-size: 13px; color: var(--muted); }

.card--accent { border-top: 3px solid var(--teal-500); }
.card--accent:nth-child(3n+2) { border-top-color: var(--gold-500); }
.card--accent:nth-child(3n) { border-top-color: var(--blue-700); }

.card__num {
  width: 38px; height: 38px; border-radius: 10px; margin-bottom: 14px;
  background: var(--blue-050); color: var(--blue-800);
  display: grid; place-items: center; font-weight: 700; font-size: 15px;
}

/* ---------------------------------------------------------- 首页首屏 */
.hero {
  position: relative; overflow: hidden; color: #fff;
  background: var(--blue-900);
  min-height: clamp(520px, 78vh, 760px);
  display: flex; align-items: center;
}
.hero__bg { position: absolute; inset: 0; }
.hero__bg img { width: 100%; height: 100%; object-fit: cover; opacity: .38; }
.hero__bg::after {
  content: ""; position: absolute; inset: 0;
  background:
    radial-gradient(120% 90% at 12% 20%, rgba(13, 58, 99, .92) 0%, rgba(13, 58, 99, .72) 45%, rgba(13, 58, 99, .55) 100%),
    linear-gradient(180deg, rgba(13, 58, 99, .35) 0%, rgba(13, 58, 99, .85) 100%);
}
.hero__inner { position: relative; width: 100%; max-width: var(--wrap); margin: 0 auto; padding: clamp(72px, 10vw, 120px) var(--gutter); }
.hero__tag {
  display: inline-block; font-size: 13px; letter-spacing: .16em; text-transform: uppercase;
  color: #8fd8cc; border: 1px solid rgba(143, 216, 204, .4); border-radius: 999px;
  padding: 5px 14px; margin-bottom: 22px;
}
.hero__motto {
  font-family: var(--font-serif); font-size: clamp(34px, 6.4vw, 68px); font-weight: 700;
  letter-spacing: .1em; line-height: 1.2; margin: 0 0 14px; color: #fff;
}
.hero__motto-en { font-size: clamp(11px, 1.4vw, 14px); letter-spacing: .34em; color: #9fc0dd; margin-bottom: 26px; }
.hero__name { font-size: clamp(19px, 2.6vw, 26px); font-weight: 700; margin-bottom: 12px; }
.hero__desc { max-width: 620px; font-size: clamp(15px, 1.7vw, 17px); color: #c6d8e9; margin-bottom: 32px; }
.hero__actions { display: flex; flex-wrap: wrap; gap: 12px; }

/* 数字条 */
.stats { background: var(--blue-900); border-top: 1px solid rgba(255, 255, 255, .12); }
.stats__grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 160px), 1fr));
  gap: 1px; background: rgba(255, 255, 255, .1);
}
.stats__item { background: var(--blue-900); padding: clamp(22px, 3vw, 34px) clamp(14px, 2vw, 24px); text-align: center; }
.stats__num {
  font-size: clamp(28px, 4vw, 42px); font-weight: 700; color: var(--gold-500);
  line-height: 1.1; letter-spacing: -.02em;
}
.stats__num small { font-size: .45em; font-weight: 600; margin-left: 3px; color: #d8b77a; letter-spacing: 0; }
.stats__label { font-size: 13px; color: #a9c0d6; margin-top: 6px; }

/* ---------------------------------------------------------- 分栏 */
.split { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 380px), 1fr)); gap: clamp(28px, 4vw, 56px); align-items: center; }
.split__media { border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-lg); }
/* 方形槽位 + 靠上的 object-position：这个位置现在放的是竖版人像，
   4:3 的横槽配 cover 会从中间裁掉头顶，3:2 更糟；1:1 刚好是头肩。
   以后换成横版照片（如校区实景）也成立——方形槽裁横图不会难看。 */
.split__media img { width: 100%; aspect-ratio: 1 / 1; object-fit: cover; object-position: center 12%; }
.split__body h2 { margin-bottom: .5em; }

/* ---------------------------------------------------------- 课程体系 */
.stage { border-bottom: 1px solid var(--line); padding: clamp(20px, 2.6vw, 30px) 0; }
.stage:last-child { border-bottom: 0; }
.stage__head { display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap; margin-bottom: 6px; }
.stage__badge {
  flex: none; font-size: 12px; font-weight: 700; letter-spacing: .1em;
  padding: 4px 10px; border-radius: 6px; background: var(--teal-050); color: var(--teal-700);
}
.stage__title { font-size: clamp(18px, 2.1vw, 22px); margin: 0; }
.stage__desc { color: var(--muted); font-size: 14px; }
.stage__list { display: flex; flex-wrap: wrap; gap: 8px; margin: 14px 0 0; padding: 0; list-style: none; }
.stage__list li { margin: 0; }
.stage__course {
  display: inline-block; padding: 7px 14px; border-radius: 999px; font-size: 14px;
  background: #fff; border: 1px solid var(--line); color: var(--ink-2);
}
.stage__course:hover { border-color: var(--teal-500); color: var(--teal-700); text-decoration: none; background: var(--teal-050); }

/* 师资卡片：左图右文 + 方形缩略图。
   方形槽对竖版人像和横版照片都成立，竖版用靠上的 object-position 保住人脸。 */
.person-card { flex-direction: row; gap: 18px; align-items: flex-start; padding: 18px; }
.person-card__photo { flex: none; width: 140px; border-radius: 10px; overflow: hidden; display: block; }
.person-card__photo img { width: 100%; aspect-ratio: 1 / 1; object-fit: cover; object-position: center 8%; }
.person-card__body { display: flex; flex-direction: column; min-width: 0; }
@media (max-width: 560px) {
  /* 窄屏不再用「小方块靠左」，那样卡片右侧会空出一块，看着像没对齐；改成通栏。
     这里不要给图片加 max-height：框一变扁，竖版人像能取到的高度就变少，
     宽度越大裁得越紧，最后只剩一张脸。保持正方形，裁切比例在各个宽度下都一致。 */
  .person-card { flex-direction: column; gap: 14px; }
  .person-card__photo { width: 100%; max-width: none; }
}

/* ---------------------------------------------------------- 列表 / 文章 */
.post-list { display: grid; gap: 16px; }
.post {
  display: grid; grid-template-columns: 1fr; gap: 18px; align-items: start;
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: clamp(18px, 2.2vw, 24px); box-shadow: var(--shadow-sm);
  transition: transform .18s, box-shadow .18s;
}
.post:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }
.post--thumb { grid-template-columns: 220px 1fr; }
.post__thumb { border-radius: 10px; overflow: hidden; }
.post__thumb img { width: 100%; aspect-ratio: 16 / 10; object-fit: cover; }
.post__title { font-size: clamp(17px, 2vw, 20px); margin-bottom: 6px; }
.post__title a { color: var(--ink); }
.post__title a:hover { color: var(--blue-800); text-decoration: none; }
.post__desc { color: var(--ink-2); font-size: 15px; margin-bottom: 10px; }
.post__meta { font-size: 13px; color: var(--muted); display: flex; gap: 14px; flex-wrap: wrap; }
@media (max-width: 620px) { .post--thumb { grid-template-columns: 1fr; } }

.pager { display: flex; gap: 8px; justify-content: center; align-items: center; margin-top: 36px; flex-wrap: wrap; }
.pager button {
  min-width: 40px; height: 40px; padding: 0 12px; border: 1px solid var(--line);
  background: #fff; border-radius: 9px; color: var(--ink-2);
}
.pager button:hover:not([disabled]) { border-color: var(--blue-700); color: var(--blue-800); }
.pager button[aria-current="true"] { background: var(--blue-800); border-color: var(--blue-800); color: #fff; font-weight: 700; }
.pager button[disabled] { opacity: .45; }
.pager__info { font-size: 13px; color: var(--muted); margin-left: 6px; }

/* 文章正文 */
.article { background: #fff; border: 1px solid var(--line); border-radius: var(--radius-lg); padding: clamp(24px, 4vw, 56px); box-shadow: var(--shadow-sm); }
.article__head { border-bottom: 1px solid var(--line); padding-bottom: 20px; margin-bottom: 28px; }
.article__title { margin-bottom: 10px; }
.article__meta { font-size: 14px; color: var(--muted); }
.prose { font-size: 16.5px; color: #22354d; max-width: 44em; }
.prose h3 { margin-top: 1.8em; padding-left: 14px; border-left: 4px solid var(--teal-500); }
/* 正文配图居中：师资页的竖版人像只有 420px 宽，窄于正文栏，
   靠左会显得像没排好；比正文栏宽的横图会缩到 100%，居中不产生变化。 */
.prose img { border-radius: var(--radius); margin: 1.4em auto; box-shadow: var(--shadow-sm); }
.prose a { text-decoration: underline; text-underline-offset: 3px; }
.prose .note, .prose .contact-line {
  background: var(--gold-050); border-left: 4px solid var(--gold-500);
  padding: 14px 18px; border-radius: 0 10px 10px 0; color: #4a3a18; margin: 1.4em 0;
}
.prose .contact-line { display: flex; gap: 12px; }
.prose .contact-line strong { flex: none; width: 5em; color: var(--blue-800); }
.prose em { font-style: normal; background: linear-gradient(transparent 62%, var(--gold-050) 62%); }

/* 表格：窄屏内部横向滚动，不撑破页面 */
.table-wrap { overflow-x: auto; margin: 1.4em 0; -webkit-overflow-scrolling: touch; }
.prose table, .course-table {
  width: 100%; border-collapse: collapse; font-size: 15px; background: #fff;
  border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden;
}
.prose th, .prose td, .course-table th, .course-table td {
  padding: 12px 16px; text-align: left; border-bottom: 1px solid var(--line); vertical-align: top;
}
.prose thead th, .course-table thead th { background: var(--blue-050); color: var(--blue-900); font-weight: 700; }
.course-table th { background: var(--bg); color: var(--ink-2); font-weight: 600; width: 6.5em; white-space: nowrap; }
.prose tr:last-child th, .prose tr:last-child td, .course-table tr:last-child th, .course-table tr:last-child td { border-bottom: 0; }
@media (max-width: 640px) {
  .prose table, .course-table { min-width: 560px; }
}

/* ---------------------------------------------------------- 图集 */
.gallery { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 240px), 1fr)); gap: 14px; }
.gallery figure { margin: 0; border-radius: var(--radius); overflow: hidden; background: #fff; border: 1px solid var(--line); }
.gallery img { width: 100%; aspect-ratio: 4 / 3; object-fit: cover; transition: transform .3s; }
.gallery figure:hover img { transform: scale(1.04); }
.gallery figcaption { padding: 12px 14px; font-size: 13px; color: var(--muted); }
/* 海报/表格类的图要完整显示，不能裁 */
.gallery--contain img { object-fit: contain; aspect-ratio: auto; background: #fff; }
.gallery--contain figure:hover img { transform: none; }

/* ---------------------------------------------------------- 表单 */
.form { display: grid; gap: 16px; }
.field { display: grid; gap: 6px; }
.field label { font-size: 14px; font-weight: 600; color: var(--ink-2); }
.field .req { color: #c0392b; }
.field input, .field textarea, .field select {
  font: inherit; padding: 11px 14px; border: 1px solid var(--line); border-radius: 10px;
  background: #fff; color: var(--ink); width: 100%;
}
.field input:focus, .field textarea:focus, .field select:focus { border-color: var(--blue-700); outline: none; box-shadow: 0 0 0 3px var(--blue-050); }
.field textarea { min-height: 120px; resize: vertical; }
.field__error { font-size: 13px; color: #c0392b; }
.field--invalid input, .field--invalid textarea { border-color: #c0392b; }
.form__note { font-size: 13px; color: var(--muted); }
.form__status { padding: 14px 18px; border-radius: 10px; font-size: 15px; }
.form__status--ok { background: var(--teal-050); color: var(--teal-700); border: 1px solid #b8e0d9; }
.form__status--err { background: #fdeceb; color: #a93226; border: 1px solid #f5c6c2; }
.form__hp { position: absolute; left: -9999px; }

/* ---------------------------------------------------------- 页脚 */
.site-footer { background: var(--blue-900); color: #a9c0d6; padding: clamp(44px, 6vw, 68px) 0 24px; font-size: 14.5px; }
.site-footer a { color: #cfe0ef; }
.site-footer a:hover { color: #fff; }
.footer__grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: clamp(24px, 3vw, 40px); }
/* 校徽外环的深蓝和页脚底色是同一个色（#0d3a63），直接放上去上半圈会融进背景、
   圆形轮廓消失，所以垫一个白色圆底当徽章。 */
.footer__brand .brand__logo {
  height: 76px; margin-bottom: 16px; padding: 5px;
  background: #fff; border-radius: 50%;
}
.footer__motto { font-family: var(--font-serif); font-size: 17px; letter-spacing: .1em; color: #fff; margin-bottom: 6px; }
.footer__motto-en { font-size: 10px; letter-spacing: .24em; color: #7b96b0; margin-bottom: 16px; }
.footer__title { color: #fff; font-size: 15px; font-weight: 700; margin-bottom: 14px; }
.footer__list { list-style: none; padding: 0; margin: 0; }
.footer__list li { margin-bottom: 9px; }
.footer__qr { width: 112px; border-radius: 10px; background: #fff; padding: 6px; }
.footer__bottom {
  margin-top: 40px; padding-top: 20px; border-top: 1px solid rgba(255, 255, 255, .12);
  display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; font-size: 13px; color: #7b96b0;
}
@media (max-width: 860px) { .footer__grid { grid-template-columns: repeat(auto-fit, minmax(min(100%, 200px), 1fr)); } }

/* ---------------------------------------------------------- 提示 / 骨架 */
.empty { text-align: center; color: var(--muted); padding: 48px 0; }


/* 滚动渐显。
   隐藏态只在 <html class="js"> 下生效（该 class 由 <head> 里的内联脚本同步加上）：
   禁用 JS 时脚本不执行，内容保持默认可见——页面上的静态兜底文案不会凭空消失。 */
.js .reveal { opacity: 0; transform: translateY(18px); transition: opacity .6s ease, transform .6s ease; }
.js .reveal.is-in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
  .js .reveal { opacity: 1; transform: none; }
}

/* 返回顶部 */
.to-top {
  position: fixed; right: 20px; bottom: 20px; z-index: 40;
  width: 44px; height: 44px; border-radius: 50%; border: 1px solid var(--line);
  background: #fff; box-shadow: var(--shadow-md); color: var(--blue-800);
  display: grid; place-items: center; opacity: 0; pointer-events: none; transition: opacity .2s;
}
.to-top[data-show="true"] { opacity: 1; pointer-events: auto; }