/* finesse · register=product · A=warm-paper+forest · B=700/400 · C=top-nav+cards
 * D=css-only-feedback · E=paper+hairline · SOUL=6 SPECTACLE=3 DENSITY=6 */
/* ============================================================
   STM32入门PCB（适配江协）· 官网
   共享样式 · product register · 手机优先 · 零依赖
   ============================================================ */

/* ---------- Token 层（所有颜色只出现在这里） ---------- */
:root{
  /* 基底 · 暖白纸面（非纯白） */
  --page:#f3efe7;
  --bg:#fffdfa;
  --panel-2:#f6f1e8;
  --border:rgba(47,32,20,.08);
  --border-strong:rgba(47,32,20,.14);

  /* 墨色 */
  --ink-1:#20180f;
  --ink-2:#463b2f;
  --ink-3:#7c6c58;

  /* 品牌 · 电路板墨绿 + 焊锡金琥珀 */
  --accent:#2f6b4f;
  --accent-2:#c08a3e;
  --accent-soft:rgba(47,107,79,.10);
  --on-accent:#ffffff;
  --on-amber:#241705;          /* near-black text on the amber (--accent-2) fill */
  --glow:rgba(47,107,79,.30);

  /* 语义（功能，非身份；--up 已移为蓝绿以避开绿色主色） */
  --up:#2c7a8c;
  --up-soft:rgba(44,122,140,.12);
  --down:#b23a30;
  --down-soft:rgba(192,69,60,.10);
  --warn:#8f5f12;                 /* darker amber so warn text clears 4.5:1 on light bg */
  --warn-soft:rgba(183,122,22,.12);
  --warn-border:rgba(183,122,22,.34);

  /* 阴影 · 向墨色偏移，绝不用纯黑 */
  --shadow:0 1px 3px rgba(60,38,20,.06);
  --shadow-md:0 8px 30px -12px rgba(60,38,20,.22);
  --shadow-lg:0 40px 90px -50px rgba(60,38,20,.34);

  /* 圆角 */
  --r:18px;
  --r-sm:11px;
  --r-lg:32px;
}

/* ---------- 基础 ---------- */
*,*::before,*::after{box-sizing:border-box}
html{overflow-x:clip;-webkit-text-size-adjust:100%}
body{
  margin:0;
  overflow-x:clip;
  background:var(--page);
  color:var(--ink-1);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",Roboto,Helvetica,Arial,sans-serif;
  font-size:16px;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
img,svg{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
button{font:inherit;cursor:pointer}
::selection{background:var(--accent-soft)}

h1,h2,h3,h4{line-height:1.25;margin:0 0 .35em;font-weight:700;color:var(--ink-1);text-wrap:balance;overflow-wrap:anywhere;min-width:0}
h1{font-size:30px;letter-spacing:-.01em}
h2{font-size:23px;letter-spacing:-.01em}
h3{font-size:18px}
p{margin:0 0 1em;color:var(--ink-2);text-wrap:pretty}
small{font-size:.85em;color:var(--ink-3)}
code,.mono{font-family:ui-monospace,"SF Mono",SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace}

.tech{
  font-family:ui-monospace,Menlo,Consolas,monospace;
  font-size:.86em;
  font-weight:600;
  color:var(--accent);
  background:var(--accent-soft);
  border-radius:6px;
  padding:1px 6px;
  white-space:nowrap;
}
.tech.amber{color:var(--warn);background:var(--warn-soft)}
.tech.neutral{color:var(--ink-3);background:var(--panel-2)}

/* ---------- 布局 ---------- */
.container{
  width:100%;
  max-width:1120px;
  margin:0 auto;
  padding:0 20px;
}
.section{padding:56px 0}
.section.tight{padding:36px 0}
.section-tinted{background:var(--panel-2)}

/* ---------- 页头导航 ---------- */
.site-header{
  position:sticky;top:0;z-index:50;
  background:var(--page);                                     /* fallback for older browsers */
  background:color-mix(in srgb,var(--page) 88%,transparent);  /* translucent over scrolled content */
  backdrop-filter:blur(8px);
  border-bottom:1px solid var(--border);
}
.nav-inner{
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  min-height:64px;
}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:16px;color:var(--ink-1)}
.brand-dot{
  width:30px;height:30px;border-radius:9px;flex:none;
  background:linear-gradient(135deg,var(--accent),var(--accent-2));
  display:grid;place-items:center;color:var(--on-accent);font-size:15px;
  box-shadow:var(--shadow);
}
.brand small{display:block;font-weight:500;font-size:11px;line-height:1;margin-top:2px}
.nav-toggle{
  display:inline-grid;place-items:center;width:44px;height:44px;border-radius:var(--r-sm);
  background:transparent;border:1px solid transparent;color:var(--ink-1);
}
.nav-toggle:hover{background:var(--panel-2)}
.site-nav{display:none;flex-direction:column;gap:2px;padding:10px 0 18px;border-top:1px solid var(--border)}
.site-nav.open{display:flex}
.site-nav a{
  padding:12px 14px;border-radius:var(--r-sm);font-weight:600;color:var(--ink-2);
  display:flex;align-items:center;gap:10px;
}
.site-nav a:hover{background:var(--panel-2);color:var(--ink-1)}
.site-nav a[aria-current="page"]{background:var(--accent-soft);color:var(--accent)}
.nav-num{font-family:ui-monospace,Menlo,Consolas,monospace;font-size:12px;color:var(--ink-3);width:20px;flex:none;text-align:right}

/* 顶部左侧 · 系列返回按钮 + 本板品牌 */
.nav-left{display:flex;align-items:center;gap:16px;min-width:0;margin-left:-100px}

/* ---------- 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:12px 22px;border-radius:var(--r-sm);border:1px solid transparent;
  font-weight:600;font-size:15px;line-height:1;white-space:nowrap;
  transition:transform .12s ease,box-shadow .12s ease,background .12s ease,border-color .12s ease;
}
.btn-primary{background:var(--accent);color:var(--on-accent);box-shadow:var(--shadow)}
.btn-primary:hover{box-shadow:var(--glow);transform:translateY(-1px)}
.btn-outline{background:var(--bg);color:var(--ink-1);border-color:var(--border-strong)}
.btn-outline:hover{border-color:var(--accent);color:var(--accent)}
.btn-amber{background:var(--accent-2);color:var(--on-amber)}
.btn-amber:hover{transform:translateY(-1px);box-shadow:0 8px 22px -10px rgba(192,138,62,.5)}
.btn-lg{padding:15px 28px;font-size:16px}
.btn-block{width:100%}
.btn:focus-visible{outline:2px solid var(--accent);outline-offset:2px}

/* ---------- 卡片 ---------- */
.card{
  background:var(--bg);border:1px solid var(--border);border-radius:var(--r);
  padding:22px;box-shadow:var(--shadow);
}
.card-head{display:flex;align-items:flex-start;gap:12px;margin-bottom:14px}
.icon-chip{
  width:38px;height:38px;border-radius:11px;flex:none;display:grid;place-items:center;
  background:var(--accent-soft);color:var(--accent);font-size:19px;
}
.icon-chip.amber{background:var(--warn-soft);color:var(--warn)}

/* 卖点卡片（首页） */
.points-grid{display:grid;gap:16px}
.point-card{display:flex;flex-direction:column}
.point-card .num{
  font-family:ui-monospace,Menlo,Consolas,monospace;font-size:13px;color:var(--accent);
  letter-spacing:.02em;margin-bottom:10px;
}
.point-card h3{font-size:19px;margin-bottom:8px}
.point-card p{margin:0}

/* 步骤（三步上手） */
.steps{display:grid;gap:16px;counter-reset:step}
.step{position:relative;padding:20px 20px 20px 70px}
.step::before{
  counter-increment:step;content:counter(step);
  position:absolute;left:20px;top:20px;width:36px;height:36px;border-radius:10px;
  display:grid;place-items:center;background:var(--accent-soft);color:var(--accent);
  font-weight:800;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:16px;
}
.step h3{margin-bottom:6px}
.step p{margin:0}

/* ---------- 两栏 / 段 ---------- */
.split{display:grid;gap:24px;align-items:center}
.split>*{min-width:0}
.split-media{border-radius:var(--r);overflow:hidden;border:1px solid var(--border);box-shadow:var(--shadow-md);background:var(--panel-2)}
.split-media img{width:100%;height:auto;display:block}
.eyebrow{
  font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;
  color:var(--accent);margin-bottom:12px;
}

/* ---------- 警告框 ---------- */
.callout{
  border:1px solid var(--warn-border);background:var(--warn-soft);
  border-left:5px solid var(--warn);border-radius:var(--r-sm);
  padding:18px 20px;margin:20px 0;
}
.callout h3{color:var(--warn);font-size:17px;margin-bottom:10px;display:flex;align-items:center;gap:8px}
.callout ol{margin:0;padding-left:20px;color:var(--ink-2)}
.callout li{margin:.4em 0}
.callout .tech{background:rgba(255,255,255,.6)}
.hint{color:var(--ink-3);font-size:.92em}
.copy-text{
  font-family:ui-monospace,"SF Mono",SFMono-Regular,Menlo,Consolas,monospace;
  font-size:13px;line-height:1.6;color:var(--ink-2);background:var(--panel-2);
  border:1px solid var(--border);border-radius:var(--r-sm);padding:12px 14px;
  margin:12px 0;white-space:pre-wrap;word-break:break-all;overflow-wrap:anywhere;
}

/* ---------- 表格 ---------- */
.table-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch;border-radius:var(--r);border:1px solid var(--border)}
table{width:100%;border-collapse:collapse;background:var(--bg);font-size:14px}
thead th{
  text-align:left;font-size:12.5px;letter-spacing:.03em;color:var(--ink-3);
  font-weight:700;padding:13px 14px;background:var(--panel-2);
  border-bottom:1px solid var(--border);white-space:nowrap;
}
tbody td{
  padding:13px 14px;border-bottom:1px solid var(--border);color:var(--ink-2);
  vertical-align:top;
}
tbody tr:nth-child(even){background:color-mix(in srgb,var(--panel-2) 45%,var(--bg))}
tbody tr:last-child td{border-bottom:none}
tbody td:first-child{font-weight:600;color:var(--ink-1)}
th.num,td.num{text-align:right;font-variant-numeric:tabular-nums}
.table-count{font-size:13px;color:var(--ink-3);margin-top:12px}

/* ---------- 列表 / 检查项 ---------- */
.check-list{list-style:none;margin:0;padding:0}
.check-list li{display:flex;gap:12px;padding:8px 0;color:var(--ink-2)}
.check-list li::before{content:"✓";color:var(--accent);font-weight:800;flex:none}
.check-list.warn li::before{content:"!";color:var(--warn)}
ul.plain{margin:0;padding-left:20px;color:var(--ink-2)}
ul.plain li{margin:.35em 0}

/* 器件清单 · 芯片网格（开箱篇等） */
.parts-grid{display:grid;gap:10px;grid-template-columns:repeat(auto-fill,minmax(150px,1fr))}
.part{
  display:flex;align-items:center;gap:8px;padding:11px 12px;
  background:var(--panel-2);border:1px solid var(--border);border-radius:var(--r-sm);
  font-size:14px;color:var(--ink-2);
}
.part::before{content:"✓";color:var(--accent);font-weight:800;flex:none}

/* ---------- 步骤编号列表（非卡片） ---------- */
.ol-steps{margin:0;padding-left:0;list-style:none;counter-reset:os}
.ol-steps>li{
  counter-increment:os;position:relative;padding:10px 0 10px 52px;color:var(--ink-2);
}
.ol-steps>li::before{
  content:counter(os);position:absolute;left:0;top:12px;width:32px;height:32px;border-radius:9px;
  display:grid;place-items:center;background:var(--panel-2);color:var(--accent);
  font-weight:700;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:14px;
}
.ol-steps strong{color:var(--ink-1)}

/* ---------- FAQ ---------- */
.faq-group{margin-bottom:32px}
.faq-group>h2{margin-bottom:4px}
.faq-group>.faq-sub{color:var(--ink-3);margin-bottom:16px}
details.faq{background:var(--bg);border:1px solid var(--border);border-radius:var(--r-sm);margin-bottom:10px;overflow:hidden}
details.faq summary{
  list-style:none;padding:18px 46px 18px 20px;font-weight:600;color:var(--ink-1);cursor:pointer;
  position:relative;display:block;
}
details.faq summary::-webkit-details-marker{display:none}
details.faq summary::after{
  content:"+";position:absolute;right:18px;top:50%;transform:translateY(-50%);
  font-size:22px;font-weight:400;color:var(--accent);
}
details.faq[open] summary::after{content:"−"}
details.faq .answer{padding:0 20px 20px;color:var(--ink-2)}
details.faq .answer p{margin:0 0 .6em}
details.faq[open]{box-shadow:var(--shadow)}

/* ---------- 灯箱（图片点击放大，如群二维码） ---------- */
.lightbox-overlay{
  position:fixed;inset:0;z-index:200;display:none;align-items:center;justify-content:center;
  background:rgba(32,24,15,.72);padding:24px;
}
.lightbox-overlay.open{display:flex}
.lightbox-box{
  position:relative;background:var(--bg);border-radius:var(--r);padding:16px;
  max-width:min(90vw,480px);width:100%;box-shadow:var(--shadow-lg);
  transform:translateY(10px);opacity:0;transition:transform .18s ease,opacity .18s ease;
}
.lightbox-overlay.open .lightbox-box{transform:none;opacity:1}
.lightbox-box img{width:100%;height:auto;display:block;border-radius:var(--r-sm)}
.lightbox-cap{margin:12px 0 0;text-align:center;color:var(--ink-2);font-size:14px}
.lightbox-close{
  position:absolute;top:10px;right:10px;width:34px;height:34px;border-radius:10px;
  background:var(--panel-2);border:1px solid var(--border);color:var(--ink-2);
  display:grid;place-items:center;font-size:20px;line-height:1;
}
.lightbox-close:hover{color:var(--ink-1)}
@media(prefers-reduced-motion:reduce){
  .lightbox-box{transition:none}
}

/* ---------- 页脚 ---------- */
.site-footer{border-top:1px solid var(--border);background:var(--panel-2);padding:36px 0 26px;text-align:center}
.footer-brand{display:flex;align-items:center;justify-content:center;gap:12px;margin-bottom:18px}
.footer-brand .brand-dot{width:32px;height:32px}
.footer-brand strong{display:block;font-size:16px;color:var(--ink-1);text-align:left}
.footer-tag{display:block;font-size:13px;color:var(--ink-3);text-align:left}
.footer-nav{display:flex;flex-wrap:wrap;justify-content:center;gap:8px 20px;padding:16px 0;border-top:1px solid var(--border)}
.footer-nav a{font-size:14px;color:var(--ink-2)}
.footer-nav a:hover{color:var(--accent)}
.footer-nav a[aria-current="page"]{color:var(--accent);font-weight:600}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:center;gap:8px 18px;align-items:center;padding-top:16px;border-top:1px solid var(--border);font-size:12.5px;color:var(--ink-3)}
.footer-icp{color:var(--ink-3)}
.footer-icp strong{color:var(--ink-2);font-weight:600}

/* ---------- Hero（首页 · 居中两行标题） ---------- */
.hero{padding:64px 0 40px;text-align:center}
.hero-inner{max-width:920px;margin:0 auto;padding:0 20px}
.hero h1{font-size:34px;line-height:1.2;letter-spacing:-.02em;margin-bottom:18px;text-wrap:balance}
.hero .lead{font-size:18px;color:var(--ink-2);max-width:54ch;margin:0 auto 10px}
.hero-tag{
  display:inline-flex;align-items:center;gap:8px;
  background:var(--accent-soft);color:var(--accent);font-weight:600;font-size:13.5px;
  padding:7px 14px;border-radius:999px;margin-bottom:20px;
}
.hero-photos{max-width:1100px;margin:34px auto 0;padding:0 20px;display:grid;gap:24px;grid-template-columns:minmax(0,1fr) minmax(0,1fr);align-items:start}
.hero-photos .photo{min-width:0}
.hero-photos .photo img{width:100%;height:auto;display:block;border-radius:var(--r)}
.hero-photos .hero-photos-col{display:flex;flex-direction:column;gap:50px;min-width:0}
.hero-photos .hero-cta{display:flex;flex-wrap:wrap;gap:12px;justify-content:center;margin-top:0}
.hero-cta{display:flex;flex-wrap:wrap;gap:12px;margin-top:8px;justify-content:center}

/* CTA 大块 */
.cta-block{background:var(--bg);border:1px solid var(--border);border-radius:var(--r-lg);padding:34px;text-align:center;box-shadow:var(--shadow)}
.cta-block h2{margin-bottom:8px}
.cta-block p{max-width:52ch;margin:0 auto 20px}
.cta-actions{display:flex;flex-wrap:wrap;gap:12px;justify-content:center}

/* ---------- 工具 ---------- */
.flex{display:flex;align-items:center;gap:8px;flex-wrap:wrap}.mt-0{margin-top:0}.mt-1{margin-top:8px}.mt-2{margin-top:16px}.mt-3{margin-top:24px}
.mb-0{margin-bottom:0}
.center{text-align:center}
.ban{
  color:var(--down);background:var(--down-soft);
  padding:2px 8px;border-radius:6px;font-size:.85em;font-weight:600;
}

/* 搜索框 */
.bar{
  display:flex;align-items:center;gap:10px;background:var(--bg);
  border:1px solid var(--border-strong);border-radius:999px;padding:12px 16px;margin:20px 0 16px;
}
.bar svg{flex:none;color:var(--ink-3)}
.bar input{border:none;outline:none;background:transparent;flex:1;font-size:15px;color:var(--ink-1)}
.bar input::placeholder{color:var(--ink-3)}
.empty-row{padding:28px;text-align:center;color:var(--ink-3);font-size:14px}

/* ---------- 侧边章节导航（左右布局） ---------- */
.page-layout{
  max-width:1120px;margin:0 auto;padding:0 20px;
  display:grid;gap:32px;align-items:start;
  grid-template-columns:minmax(0,1fr);
}
.page-content{min-width:0}
.page-content .container{max-width:none;padding-left:0;padding-right:0}
.page-content h2,.page-content h3{scroll-margin-top:96px}
.toc{display:none}
@media(min-width:980px){
  .page-layout{grid-template-columns:250px minmax(0,1fr)}
  .toc{
    display:block;position:sticky;top:88px;align-self:start;
    max-height:calc(100vh - 108px);overflow-y:auto;
    background:var(--bg);border:1px solid var(--border);border-radius:var(--r);
    padding:16px 14px;box-shadow:var(--shadow);
  }
  .toc-title{
    font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;
    color:var(--ink-3);margin:0 0 12px;padding:0 6px;
  }
  .toc a{
    display:block;padding:8px 10px;margin-bottom:2px;border-radius:9px;
    color:var(--ink-2);font-size:13.5px;line-height:1.45;font-weight:500;
    border-left:2px solid transparent;transition:color .15s,background .15s,border-color .15s;
  }
  .toc a:hover{background:var(--panel-2);color:var(--ink-1)}
  .toc a.active{color:var(--accent);background:var(--accent-soft);border-left-color:var(--accent);font-weight:600}
}

/* ---------- 响应式 ---------- */
@media(min-width:760px){
  .nav-toggle{display:none}
  .site-nav{display:flex;flex-direction:row;gap:4px;padding:0;border-top:none;background:transparent}
  .site-nav a{padding:9px 13px;font-size:14.5px}
  .nav-num{display:none}
  .points-grid{grid-template-columns:repeat(3,minmax(0,1fr))}
  .steps{grid-template-columns:repeat(3,minmax(0,1fr))}
  .split{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}
  .hero h1{font-size:40px}
  h1{font-size:34px}
  h2{font-size:26px}
}
@media(min-width:980px){
  .hero h1{font-size:46px}
  .section{padding:72px 0}
  .cta-block{padding:44px}
}
@media(max-width:759px){
  .hero-photos{grid-template-columns:minmax(0,1fr)}
  .hero-photos .hero-cta{justify-content:center}
  .hero h1{font-size:30px}
}

/* ---------- 手机端专属优化（≤759px）· 单独排版，非缩放 ---------- */
@media(max-width:759px){
  .container{padding:0 18px}
  .section{padding:40px 0}
  .section.tight{padding:28px 0}

  /* 页头：修正 -100px 在手机溢出视口、品牌被裁切的问题 */
  .nav-left{margin-left:0;gap:10px}
  .nav-inner{gap:10px}
  .brand{font-size:14.5px;gap:8px}
  .brand small{font-size:10px}
  .brand-dot{width:26px;height:26px}

  /* 主按钮：全宽堆叠，方便拇指点击 */
  .hero-cta,.hero-photos .hero-cta,.cta-actions{flex-direction:column;align-items:stretch;gap:12px}
  .hero-cta .btn,.cta-actions .btn{width:100%;justify-content:center}

  /* Hero */
  .hero{padding:48px 0 30px}
  .hero .lead{font-size:16px}
  .hero-tag{font-size:13px;padding:6px 12px}
  .hero-photos{gap:18px;margin-top:26px}
  .hero-photos .hero-photos-col{gap:28px}

  /* 卡片 / 步骤 / 拆分 / 注意事项 */
  .card{padding:18px}
  .points-grid,.steps{gap:14px}
  .step{padding:16px 16px 16px 62px}
  .step::before{left:16px;top:16px;width:32px;height:32px;font-size:14px}
  .split{gap:20px}
  .callout{padding:16px 16px}
  .copy-text{font-size:12.5px;padding:11px 12px}

  /* 表格 */
  .table-scroll{border-radius:var(--r-sm)}
  table{font-size:13px}
  thead th,tbody td{padding:11px 12px}

  /* CTA 大块 */
  .cta-block{padding:26px 20px;border-radius:var(--r)}
}

/* 超小屏（≤380px）微调 */
@media(max-width:380px){
  .container{padding:0 14px}
  .hero h1{font-size:26px}
}

/* ---------- 动效（仅反馈，尊重系统设置） ---------- */
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.01ms!important;transition-duration:.01ms!important;scroll-behavior:auto!important}
}
@media (prefers-reduced-motion:no-preference){
  html{scroll-behavior:smooth}
  .reveal{opacity:0;transform:translateY(14px);animation:rise .5s ease forwards}
  .reveal:nth-child(2){animation-delay:.06s}
  .reveal:nth-child(3){animation-delay:.12s}
  .reveal:nth-child(4){animation-delay:.18s}
  @keyframes rise{to{opacity:1;transform:none}}
}

/* 焦点可见 */
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}

/* ============================================================
   系列返回按钮（Uiverse · SendMessage · 适配站点橙色）
   ============================================================ */
.button {
  --primary: #e8650d;
  --neutral-1: #fbf8f1;
  --neutral-2: #ece3d2;
  --radius: 14px;
  cursor: pointer;
  border-radius: var(--radius);
  text-shadow: 0 1px 1px rgba(0, 0, 0, 0.3);
  border: none;
  box-shadow: 0 0.5px 0.5px 1px rgba(255, 255, 255, 0.2), 0 10px 20px rgba(0, 0, 0, 0.2), 0 4px 5px 0px rgba(0, 0, 0, 0.05);
  display: inline-flex; align-items: center; justify-content: center; position: relative;
  transition: all 0.3s ease;
  min-width: 200px; padding: 20px; height: 68px;
  font-family: "Galano Grotesque", Poppins, Montserrat, system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-style: normal; font-size: 18px; font-weight: 600; color: #26201a; text-decoration: none; background: transparent;
}
.button:hover { transform: scale(1.02); box-shadow: 0 0 1px 2px rgba(255,255,255,.3), 0 15px 30px rgba(0,0,0,.3), 0 10px 3px -3px rgba(0,0,0,.04); }
.button:active { transform: scale(1); box-shadow: 0 0 1px 2px rgba(255,255,255,.3), 0 10px 3px -3px rgba(0,0,0,.2); }
.button::after { content:""; position:absolute; inset:0; border-radius:var(--radius); border:2.5px solid transparent; background: linear-gradient(var(--neutral-1),var(--neutral-2)) padding-box, linear-gradient(to bottom, rgba(0,0,0,.1), rgba(0,0,0,.45)) border-box; z-index:0; transition:all .4s ease; }
.button:hover::after { transform:scale(1.05,1.1); box-shadow: inset 0 -1px 3px 0 rgba(255,255,255,1); }
.button::before { content:""; inset:7px 6px 6px 6px; position:absolute; background: linear-gradient(to top, var(--neutral-1), var(--neutral-2)); border-radius:30px; filter:blur(.5px); z-index:2; }
.state { padding-left:29px; z-index:2; display:flex; position:relative; }
.state p { display:flex; align-items:center; justify-content:center; margin:0; line-height:1; }
.state .icon { position:absolute; left:0; top:0; bottom:0; margin:auto; transform:scale(1.25); transition:all .3s ease; display:flex; align-items:center; justify-content:center; }
.state .icon svg { overflow:visible; }
.outline { position:absolute; border-radius:inherit; overflow:hidden; z-index:1; opacity:0; transition:opacity .4s ease; inset:-2px -3.5px; }
.outline::before { content:""; position:absolute; inset:-100%; background:conic-gradient(from 180deg, transparent 60%, #fff 80%, transparent 100%); animation:spin 2s linear infinite; animation-play-state:paused; }
@keyframes spin { 0%{transform:rotate(0deg)} 100%{transform:rotate(360deg)} }
.button:hover .outline { opacity:1; }
.button:hover .outline::before { animation-play-state:running; }
.state p span { display:block; opacity:0; animation:slideDown .8s ease forwards calc(var(--i)*.03s); }
.button:hover p span { opacity:1; animation:wave .5s ease forwards calc(var(--i)*.02s); }
.button:focus p span { opacity:1; animation:disappear .6s ease forwards calc(var(--i)*.03s); }
@keyframes wave { 30%{opacity:1;transform:translateY(4px) translateX(0) rotate(0)} 50%{opacity:1;transform:translateY(-3px) translateX(0) rotate(0);color:var(--primary)} 100%{opacity:1;transform:translateY(0) translateX(0) rotate(0)} }
@keyframes slideDown { 0%{opacity:0;transform:translateY(-20px) translateX(5px) rotate(-90deg);color:var(--primary);filter:blur(5px)} 30%{opacity:1;transform:translateY(4px) translateX(0) rotate(0);filter:blur(0)} 50%{opacity:1;transform:translateY(-3px) translateX(0) rotate(0)} 100%{opacity:1;transform:translateY(0) translateX(0) rotate(0)} }
@keyframes disappear { from{opacity:1} to{opacity:0;transform:translateX(5px) translateY(20px);color:var(--primary);filter:blur(5px)} }
.state--default .icon svg { animation:land .6s ease forwards; }
.button:hover .state--default .icon { transform:rotate(45deg) scale(1.25); }
.button:focus .state--default svg { animation:takeOff .8s linear forwards; }
.button:focus .state--default .icon { transform:rotate(0) scale(1.25); }
@keyframes takeOff { 0%{opacity:1} 60%{opacity:1;transform:translateX(70px) rotate(45deg) scale(2)} 100%{opacity:0;transform:translateX(160px) rotate(45deg) scale(0)} }
@keyframes land { 0%{transform:translateX(-60px) translateY(30px) rotate(-50deg) scale(2);opacity:0;filter:blur(3px)} 100%{transform:translateX(0) translateY(0) rotate(0);opacity:1;filter:blur(0)} }
.state--default .icon::before { content:""; position:absolute; top:50%; height:2px; width:0; left:-5px; background:linear-gradient(to right, transparent, rgba(0,0,0,.5)); }
.button:focus .state--default .icon::before { animation:contrail .8s linear forwards; }
@keyframes contrail { 0%{width:0;opacity:1} 8%{width:15px} 60%{opacity:.7;width:80px} 100%{opacity:0;width:160px} }
.state--sent { display:none; }
.state--sent svg { transform:scale(1.25); margin-right:8px; }
.button:focus .state--default { position:absolute; }
.button:focus .state--sent { display:flex; }
.button:focus .state--sent span { opacity:0; animation:slideDown .8s ease forwards calc(var(--i)*.2s); }
.button:focus .state--sent .icon svg { opacity:0; animation:appear 1.2s ease forwards .8s; }
@keyframes appear { 0%{opacity:0;transform:scale(4) rotate(-40deg);color:var(--primary);filter:blur(4px)} 30%{opacity:1;transform:scale(.6);filter:blur(1px)} 50%{opacity:1;transform:scale(1.2);filter:blur(0)} 100%{opacity:1;transform:scale(1)} }
@media (max-width:520px){ .button{min-width:178px;padding:16px 18px;height:60px;font-size:16px} .state{padding-left:26px} }
@media (prefers-reduced-motion:reduce){
  .button,.button::before,.button::after,.button .outline,.button .outline::before,.button .state,.button .state p span,.button .state .icon,.button .state .icon svg,.button .state--default .icon::before{animation:none!important;transition:none!important}
  .button .state p span{opacity:1}
  .button .outline,.button:hover .outline{opacity:0}
  .button .state--sent{display:none}
  .button:focus .state--default{position:static}
  .button .state--default .icon{transform:scale(1.25)}
}
/* 页头紧凑版 · 「小熊的毕设工坊」返回按钮 */
.button--nav { min-width:auto; height:46px; padding:9px 18px; font-size:15px; --radius:12px; }
.button--nav .state { padding-left:26px; }
.button--nav .state .icon { transform:scale(1.1); }
@media (max-width:520px){ .button--nav{height:41px;padding:7px 14px;font-size:14px} .button--nav .state{padding-left:24px} }