:root{
  --bg:#f4f6f9;
  --bg-elev:#ffffff;
  --bg-elev-2:#f0f3f8;
  --text:#1b2430;
  --text-dim:#5b6675;
  --border:#e2e6ed;
  --accent:#2563eb;
  --accent-dim:#dbe6fd;
  --accent-text:#ffffff;
  --accent-2:#0d9488;
  --danger:#dc2626;
  --warn:#b45309;
  --radius:14px;
  --shadow:0 1px 2px rgba(16,24,40,.04), 0 4px 14px rgba(16,24,40,.06);
  color-scheme: light;
}
:root[data-theme="dark"]{
  --bg:#12151c;
  --bg-elev:#1b1f29;
  --bg-elev-2:#232836;
  --text:#e7ebf3;
  --text-dim:#9aa4b5;
  --border:#2b3040;
  --accent:#5b8def;
  --accent-dim:#233252;
  --accent-text:#0b1220;
  --accent-2:#2dd4bf;
  --danger:#f87171;
  --warn:#fbbf24;
  --shadow:0 1px 2px rgba(0,0,0,.3), 0 8px 24px rgba(0,0,0,.35);
  color-scheme: dark;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:#12151c;
    --bg-elev:#1b1f29;
    --bg-elev-2:#232836;
    --text:#e7ebf3;
    --text-dim:#9aa4b5;
    --border:#2b3040;
    --accent:#5b8def;
    --accent-dim:#233252;
    --accent-text:#0b1220;
    --accent-2:#2dd4bf;
    --danger:#f87171;
    --warn:#fbbf24;
    --shadow:0 1px 2px rgba(0,0,0,.3), 0 8px 24px rgba(0,0,0,.35);
    color-scheme: dark;
  }
}

*{box-sizing:border-box;}
html,body{margin:0;padding:0;}
body{
  background:var(--bg);
  color:var(--text);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
#app{min-height:100vh;display:flex;flex-direction:column;}
a{color:inherit;text-decoration:none;}

/* topbar */
.topbar{
  display:flex;align-items:center;gap:16px;
  padding:12px 20px;
  background:var(--bg-elev);
  border-bottom:1px solid var(--border);
  position:sticky;top:0;z-index:20;
}
.brand{display:flex;align-items:center;gap:8px;font-size:17px;white-space:nowrap;}
.brand-icon{font-size:22px;}
.brand-text strong{color:var(--accent);}
.search-wrap{flex:1;max-width:520px;margin-left:auto;}
#searchInput{
  width:100%;padding:9px 14px;border-radius:999px;border:1px solid var(--border);
  background:var(--bg-elev-2);color:var(--text);font-size:14px;outline:none;
}
#searchInput:focus{border-color:var(--accent);}
.icon-btn{
  background:var(--bg-elev-2);border:1px solid var(--border);border-radius:10px;
  width:38px;height:38px;cursor:pointer;font-size:16px;color:var(--text);
  display:flex;align-items:center;justify-content:center;flex:0 0 auto;
}
.icon-btn:hover{border-color:var(--accent);}

main{flex:1;width:100%;max-width:1180px;margin:0 auto;padding:24px 20px 60px;}

.site-footer{
  width:100%;max-width:1180px;margin:0 auto;padding:18px 20px 28px;
  border-top:1px solid var(--border);
}
.site-footer p{margin:0;color:var(--text-dim);font-size:12.5px;line-height:1.6;}

/* ---- home ---- */
.hero{margin-bottom:22px;}
.hero h1{font-size:26px;margin:0 0 6px;}
.hero p{color:var(--text-dim);margin:0;font-size:15px;max-width:640px;}

.chips{display:flex;gap:8px;flex-wrap:wrap;margin:18px 0;}
.chip{
  padding:7px 14px;border-radius:999px;border:1px solid var(--border);
  background:var(--bg-elev);color:var(--text-dim);cursor:pointer;font-size:13px;font-weight:500;
}
.chip.active{background:var(--accent);border-color:var(--accent);color:var(--accent-text);}

.grid{
  display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:14px;margin-top:6px;
}
.card{
  background:var(--bg-elev);border:1px solid var(--border);border-radius:var(--radius);
  padding:18px;cursor:pointer;box-shadow:var(--shadow);transition:transform .12s, border-color .12s;
  display:flex;flex-direction:column;gap:8px;
}
.card:hover{transform:translateY(-2px);border-color:var(--accent);}
.card .icon{font-size:26px;}
.card h3{margin:0;font-size:15.5px;}
.card p{margin:0;color:var(--text-dim);font-size:13px;line-height:1.4;}
.card .tag{
  align-self:flex-start;font-size:11px;padding:3px 9px;border-radius:999px;
  background:var(--accent-dim);color:var(--accent);font-weight:600;margin-top:4px;
}
.empty-state{padding:40px 0;text-align:center;color:var(--text-dim);}

/* ---- tool view ---- */
.back-btn{
  display:inline-flex;align-items:center;gap:6px;background:none;border:none;color:var(--accent);
  font-size:14px;cursor:pointer;padding:0;margin-bottom:14px;font-weight:600;
}
.tool-header{display:flex;align-items:flex-start;gap:14px;margin-bottom:20px;}
.tool-header .icon{font-size:32px;line-height:1;}
.tool-header h2{margin:0 0 4px;font-size:22px;}
.tool-header p{margin:0;color:var(--text-dim);font-size:14px;max-width:640px;}

.tool-layout{display:grid;grid-template-columns:1fr;gap:18px;}
@media(min-width:860px){
  .tool-layout{grid-template-columns:1.1fr 1fr;align-items:start;}
}

.panel{
  background:var(--bg-elev);border:1px solid var(--border);border-radius:var(--radius);
  padding:20px;box-shadow:var(--shadow);
}
.panel h4{margin:0 0 14px;font-size:14px;text-transform:uppercase;letter-spacing:.04em;color:var(--text-dim);}
.panel + .panel{margin-top:16px;}

.field{margin-bottom:14px;}
.field label{display:block;font-size:13px;color:var(--text-dim);margin-bottom:5px;font-weight:500;}
.field .hint{font-size:11.5px;color:var(--text-dim);opacity:.8;margin-top:4px;}
.row{display:grid;gap:10px;}
.row.cols-2{grid-template-columns:1fr 1fr;}
.row.cols-3{grid-template-columns:1fr 1fr 1fr;}

input[type=number],input[type=text],select{
  width:100%;padding:9px 11px;border-radius:9px;border:1px solid var(--border);
  background:var(--bg-elev-2);color:var(--text);font-size:14px;outline:none;
  font-family:inherit;
}
input[type=number]:focus,input[type=text]:focus,select:focus{border-color:var(--accent);}
select{cursor:pointer;}

.inline-check{display:flex;align-items:center;gap:8px;font-size:13.5px;color:var(--text);margin-bottom:14px;cursor:pointer;}
.inline-check input{width:16px;height:16px;accent-color:var(--accent);}

.seg{display:flex;border:1px solid var(--border);border-radius:9px;overflow:hidden;margin-bottom:14px;}
.seg button{
  flex:1;padding:9px 8px;background:var(--bg-elev-2);border:none;color:var(--text-dim);
  cursor:pointer;font-size:13px;font-weight:600;border-right:1px solid var(--border);
}
.seg button:last-child{border-right:none;}
.seg button.active{background:var(--accent);color:var(--accent-text);}

.result-panel{position:sticky;top:76px;}
.result-title{font-size:14px;text-transform:uppercase;letter-spacing:.04em;color:var(--text-dim);margin-bottom:14px;}
.result-main{
  background:linear-gradient(135deg,var(--accent),var(--accent-2));
  color:#fff;border-radius:12px;padding:18px;margin-bottom:14px;
}
.result-main .value{font-size:28px;font-weight:800;line-height:1.2;}
.result-main .label{font-size:12.5px;opacity:.9;margin-top:2px;}
.result-list{display:flex;flex-direction:column;gap:0;}
.result-row{
  display:flex;justify-content:space-between;align-items:baseline;padding:10px 0;
  border-bottom:1px dashed var(--border);font-size:13.5px;gap:10px;
}
.result-row:last-child{border-bottom:none;}
.result-row .k{color:var(--text-dim);}
.result-row .v{font-weight:700;text-align:right;white-space:nowrap;}
.result-row .v small{font-weight:500;color:var(--text-dim);font-size:11.5px;}
.note-box{
  margin-top:14px;padding:12px 14px;background:var(--bg-elev-2);border-radius:10px;
  font-size:12.5px;color:var(--text-dim);line-height:1.5;border-left:3px solid var(--accent);
}
.note-box b{color:var(--text);}

@media(max-width:859px){
  .result-panel{position:static;}
}

.section-divider{
  font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.05em;
  color:var(--accent);margin:18px 0 10px;
}
.section-divider:first-child{margin-top:0;}

::-webkit-scrollbar{width:10px;height:10px;}
::-webkit-scrollbar-thumb{background:var(--border);border-radius:6px;}

/* ---- article: guide / faq / related ---- */
.tool-article{
  margin-top:36px;padding-top:28px;border-top:1px solid var(--border);
  max-width:820px;
}
.article-intro{font-size:15px;line-height:1.7;color:var(--text);margin-bottom:22px;}
.article-intro p{margin:0;}
.article-section{margin-bottom:24px;}
.article-section h3{font-size:16.5px;margin:0 0 10px;}
.article-section p{margin:0 0 10px;font-size:14px;line-height:1.7;color:var(--text-dim);}
.article-section ul{margin:0;padding-left:20px;font-size:14px;line-height:1.75;color:var(--text-dim);}
.article-section ul li{margin-bottom:6px;}
.article-section b{color:var(--text);}
.article-section a{color:var(--accent);font-weight:600;text-decoration:underline;text-underline-offset:2px;}

.table-wrap{overflow-x:auto;margin:4px 0 8px;border-radius:10px;border:1px solid var(--border);}
.info-table{width:100%;border-collapse:collapse;font-size:13.5px;min-width:420px;}
.info-table th,.info-table td{padding:9px 12px;text-align:left;border-bottom:1px solid var(--border);white-space:nowrap;}
.info-table thead th{background:var(--bg-elev-2);color:var(--text-dim);font-weight:700;font-size:12px;text-transform:uppercase;letter-spacing:.03em;}
.info-table tbody tr:last-child td{border-bottom:none;}
.info-table td{color:var(--text-dim);}
.info-table td:first-child{color:var(--text);font-weight:600;}

.tips-box{
  background:var(--bg-elev);border:1px solid var(--border);border-left:3px solid var(--accent-2);
  border-radius:10px;padding:16px 18px;margin:20px 0 28px;
}
.tips-box h4{margin:0 0 10px;font-size:14px;}
.tips-box ul{margin:0;padding-left:20px;font-size:13.5px;line-height:1.7;color:var(--text-dim);}
.tips-box li{margin-bottom:6px;}

.faq-section h3{font-size:16.5px;margin:0 0 12px;}
.faq-item{
  background:var(--bg-elev);border:1px solid var(--border);border-radius:10px;
  padding:2px 16px;margin-bottom:8px;
}
.faq-item summary{
  padding:12px 0;font-size:14px;font-weight:600;cursor:pointer;list-style:none;
  display:flex;justify-content:space-between;align-items:center;gap:10px;
}
.faq-item summary::-webkit-details-marker{display:none;}
.faq-item summary::after{content:'+';font-size:18px;color:var(--accent);flex:0 0 auto;font-weight:400;}
.faq-item[open] summary::after{content:'−';}
.faq-item .faq-a{padding:0 0 14px;font-size:13.5px;line-height:1.7;color:var(--text-dim);}

.related-tools{margin-top:32px;max-width:960px;}
.related-tools h3{font-size:16px;margin:0 0 14px;}
.related-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:12px;}
.related-card{
  display:flex;align-items:flex-start;gap:10px;padding:14px;border-radius:12px;
  background:var(--bg-elev);border:1px solid var(--border);
}
.related-card:hover{border-color:var(--accent);}
.related-card .icon{font-size:20px;line-height:1.3;}
.related-card b{display:block;font-size:13.5px;margin-bottom:3px;}
.related-card small{display:block;font-size:12px;color:var(--text-dim);line-height:1.4;}