/* ======================================================================
   自行车坐垫高度计算器 · 独立设计（碳纤维黑 × 荧光黄绿骑行主题）
   浅色 = 水泥灰路面 + 碳黑卡片；深色 = 夜骑反光条
   ====================================================================== */
.bsh{
  --ink:#17190f; --sub:#5c6048; --faint:#989c82;
  --bg:#f2f3ee; --card:#ffffff; --card2:#eaece2; --line:#d6d9c9; --line2:#e3e6d8;
  --pri:#3d4421; --pri-2:#55602c; --lime:#c6f22a; --lime-deep:#8fae10; --lime-soft:#eef7c8;
  --carbon:#1b1d15; --carbon-2:#2a2d20;
  --red:#b42323; --red-soft:#fdecec;
  --r:14px;
  --shadow:0 1px 2px rgba(23,25,15,.06),0 12px 30px rgba(23,25,15,.10);
  color:var(--ink);
  font-family:"Segoe UI","PingFang SC","HarmonyOS Sans SC","Microsoft YaHei",-apple-system,sans-serif;
  font-size:15px; line-height:1.75;
  background:
    repeating-linear-gradient(115deg, transparent 0 26px, rgba(214,217,201,.35) 26px 27px),
    radial-gradient(860px 400px at 92% -140px, rgba(198,242,42,.16), transparent 60%),
    var(--bg);
  padding:0 16px 58px;
}
:root[data-theme="dark"] .bsh{
  --ink:#e9ecd9; --sub:#a3a88c; --faint:#6d7258;
  --bg:#101208; --card:#1a1d12; --card2:#22261a; --line:#3a4030; --line2:#2d3224;
  --pri:#c6f22a; --pri-2:#d9ff5e; --lime:#c6f22a; --lime-deep:#a4cc1c; --lime-soft:rgba(198,242,42,.12);
  --carbon:#0b0c06; --carbon-2:#1a1d12;
  --red:#f87171; --red-soft:rgba(248,113,113,.12);
  --shadow:0 1px 2px rgba(0,0,0,.5),0 14px 34px rgba(0,0,0,.5);
}
.bsh *{box-sizing:border-box;}
.bsh b{font-weight:700;}
.bsh-wrap{max-width:1080px;margin:0 auto;}
.bsh-mono{font-family:"JetBrains Mono",ui-monospace,Consolas,monospace;font-weight:700;}

/* ---------- Hero：碳板 + 荧光条纹 ---------- */
.bsh-hero{margin-top:22px;border-radius:16px;overflow:hidden;box-shadow:var(--shadow);
  background:
    repeating-linear-gradient(45deg, rgba(255,255,255,.035) 0 6px, transparent 6px 12px),
    linear-gradient(140deg,var(--carbon) 0%,var(--carbon-2) 70%,#3a4030 130%);
  border:1px solid #000;}
.bsh-stripe{height:8px;background:repeating-linear-gradient(90deg,var(--lime) 0 34px,transparent 34px 46px);}
.bsh-hero-body{padding:24px 28px 22px;display:flex;gap:20px;align-items:center;flex-wrap:wrap;}
.bsh-bike{width:112px;height:82px;flex:none;}
.bsh-hero-txt{flex:1;min-width:260px;}
.bsh-hero h1{margin:0 0 6px;font-size:clamp(23px,3.4vw,31px);font-weight:900;color:#f5f7e8;letter-spacing:.01em;}
.bsh-hero h1 em{font-style:normal;color:var(--lime);}
.bsh-hero p{margin:0;color:#a9ad8e;font-size:14.5px;max-width:680px;}
.bsh-hero p em{font-style:normal;color:#d9e6a0;font-weight:700;}

/* ---------- 模式切换 ---------- */
.bsh-tabs{display:flex;gap:8px;flex-wrap:wrap;margin-top:20px;}
.bsh-tab{border:1.5px solid var(--line);background:var(--card);color:var(--sub);border-radius:10px;padding:8px 16px;font-size:14px;font-weight:800;cursor:pointer;font-family:inherit;transition:all .15s;}
.bsh-tab:hover{border-color:var(--lime-deep);color:var(--ink);}
.bsh-tab.on{background:var(--carbon);border-color:var(--carbon);color:var(--lime);}
:root[data-theme="dark"] .bsh-tab.on{background:var(--lime);color:#1b1d15;}

/* ---------- 工作台 ---------- */
.bsh-desk{display:grid;grid-template-columns:360px 1fr;gap:18px;margin-top:16px;}
@media (max-width:920px){.bsh-desk{grid-template-columns:1fr;}}
.bsh-card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--shadow);padding:20px 22px;}
.bsh-card h2{margin:0 0 4px;font-size:16px;font-weight:900;display:flex;align-items:center;gap:8px;}
.bsh-card h2::before{content:'';width:5px;height:18px;border-radius:3px;background:var(--lime);}
.bsh-tip{font-size:12.5px;color:var(--sub);margin:0 0 14px;}
.bsh-field{margin-bottom:12px;}
.bsh-field label{display:block;font-size:13px;font-weight:700;color:var(--sub);margin-bottom:4px;}
.bsh-in,.bsh-sel{width:100%;border:1.5px solid var(--line);background:var(--card2);color:var(--ink);border-radius:10px;padding:9px 12px;font-size:14.5px;outline:none;font-family:inherit;}
.bsh-in:focus,.bsh-sel:focus{border-color:var(--lime-deep);box-shadow:0 0 0 3px var(--lime-soft);}
.bsh-btn{border:none;border-radius:10px;padding:9px 18px;font-size:14px;font-weight:800;cursor:pointer;font-family:inherit;transition:all .15s;}
.bsh-btn-go{background:var(--carbon);color:var(--lime);}
:root[data-theme="dark"] .bsh-btn-go{background:var(--lime);color:#1b1d15;}
.bsh-btn-go:hover{opacity:.88;}
.bsh-btn-ghost{background:var(--card2);color:var(--ink);border:1.5px solid var(--line);}
.bsh-btn-ghost:hover{border-color:var(--lime-deep);}
.bsh-row{display:flex;gap:8px;flex-wrap:wrap;margin-top:6px;}
.bsh-msg{margin-top:10px;font-size:13px;min-height:20px;font-weight:700;}
.bsh-msg.err{color:var(--red);}
.bsh-msg.ok{color:var(--lime-deep);}

/* ---------- 结果 ---------- */
.bsh-big{display:flex;gap:12px;flex-wrap:wrap;margin-bottom:14px;}
.bsh-stat{flex:1;min-width:130px;background:var(--carbon);border-radius:12px;padding:14px;text-align:center;}
.bsh-stat i{display:block;font-style:normal;font-size:12px;color:#a9ad8e;font-weight:700;}
.bsh-stat b{font-size:26px;color:var(--lime);}
.bsh-stat u{text-decoration:none;font-size:12px;color:#7d8168;}
.bsh-scale{margin:10px 0 4px;height:14px;border-radius:99px;position:relative;
  background:linear-gradient(90deg,#e8b04a 0 18%,var(--lime) 18% 82%,#e8b04a 82% 100%);
  border:1px solid var(--line);}
.bsh-scale i{position:absolute;top:-4px;width:4px;height:22px;border-radius:2px;background:var(--carbon);}
:root[data-theme="dark"] .bsh-scale i{background:#fff;}
.bsh-scale-lb{display:flex;justify-content:space-between;font-size:11.5px;color:var(--faint);margin-top:4px;}
.bsh-advice{margin-top:12px;border-radius:10px;padding:10px 14px;font-size:14px;border:1px solid var(--line2);background:var(--card2);}
.bsh-advice.hl{background:var(--lime-soft);}
.bsh-advice.bad{background:var(--red-soft);}
.bsh-advice b{color:var(--ink);}
.bsh-steps{margin:10px 0 0;padding-left:20px;font-size:13.5px;color:var(--sub);}
.bsh-steps li{margin-bottom:5px;}
.bsh-steps b{color:var(--ink);}

/* ---------- FAQ ---------- */
.bsh-faq{margin-top:34px;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:22px 26px;box-shadow:var(--shadow);}
.bsh-faq h2{margin:0 0 12px;font-size:19px;font-weight:900;}
.bsh-faq h3{margin:18px 0 6px;font-size:15.5px;font-weight:800;color:var(--lime-deep);}
.bsh-faq p{margin:0;color:var(--sub);font-size:14px;}
.bsh-faq p b{color:var(--ink);}