:root{
  --bg:#f6f7fb; --surface:#ffffff; --surface2:#f1f2f7;
  --text:#14161f; --muted:#5b6172; --line:#e5e7ef;
  --brand:#4f46e5; --brand2:#7c3aed; --brand-soft:#eef0ff;
  --ok:#0e9f6e; --warn:#c2410c; --danger:#dc2626;
  --radius:14px; --shadow:0 6px 24px rgba(20,22,31,.07);
  --max:1120px;
}
[data-theme="dark"]{
  --bg:#0c0e16; --surface:#141826; --surface2:#1b2133;
  --text:#eef0f7; --muted:#9aa3b8; --line:#242b42;
  --brand:#818cf8; --brand2:#a78bfa; --brand-soft:#1d2140;
  --shadow:0 6px 24px rgba(0,0,0,.4);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Inter,Arial,sans-serif;-webkit-font-smoothing:antialiased}
.wrap{max-width:var(--max);margin:0 auto;padding:0 20px}
.muted{color:var(--muted)}
.skip{position:absolute;left:-9999px;top:0;background:var(--brand);color:#fff;padding:8px 14px;border-radius:0 0 8px 0}
.skip:focus{left:0}
/* header */
.topbar{position:sticky;top:0;z-index:50;background:color-mix(in srgb,var(--surface) 88%,transparent);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.topbar-in{display:flex;align-items:center;gap:18px;padding:12px 20px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:9px;text-decoration:none;color:var(--text);font-weight:800;font-size:1.25rem}
.brand-mark{width:32px;height:32px;border-radius:9px;background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff;display:grid;place-items:center;font-weight:900}
.mainnav{display:flex;gap:4px}
.mainnav a{padding:8px 12px;border-radius:9px;text-decoration:none;color:var(--muted);font-weight:600}
.mainnav a:hover{background:var(--surface2);color:var(--text)}
.mainnav a.on{background:var(--brand-soft);color:var(--brand)}
.top-actions{margin-left:auto;display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.searchbox{position:relative}
.searchbox input{width:min(320px,60vw);padding:10px 14px;border-radius:11px;border:1px solid var(--line);background:var(--surface);color:var(--text)}
.search-results{position:absolute;top:110%;left:0;right:0;background:var(--surface);border:1px solid var(--line);border-radius:12px;box-shadow:var(--shadow);overflow:hidden;max-height:340px;overflow-y:auto}
.search-results a{display:block;padding:10px 14px;text-decoration:none;color:var(--text);border-bottom:1px solid var(--line)}
.search-results a small{color:var(--muted);display:block}
.search-results a:hover{background:var(--brand-soft)}
.langswitch{position:relative;border:1px solid var(--line);border-radius:10px;background:var(--surface)}
.langswitch summary{list-style:none;cursor:pointer;padding:7px 10px;color:var(--text);font-weight:700;font-size:.8rem;user-select:none}
.langswitch summary::-webkit-details-marker{display:none}
.langswitch summary::after{content:" ▾";color:var(--muted)}
.langmenu{position:absolute;right:0;top:calc(100% + 6px);min-width:100%;background:var(--surface);border:1px solid var(--line);border-radius:10px;box-shadow:var(--shadow);overflow:hidden;z-index:50}
.langmenu a{display:block;padding:7px 12px;text-decoration:none;color:var(--muted);font-weight:700;font-size:.8rem;white-space:nowrap}
.langmenu a.on{background:var(--brand);color:#fff}
.langmenu a:hover:not(.on){background:var(--surface2)}
.langswitch .flag{width:18px;height:13px;object-fit:cover;border-radius:2px;box-shadow:0 0 0 1px var(--line);vertical-align:-2px;margin:0 .3em}
.iconbtn{border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:10px;padding:8px 11px;cursor:pointer}
/* hero */
.hero{padding:56px 0 26px;text-align:center}
.badge{display:inline-block;background:var(--brand-soft);color:var(--brand);font-weight:700;font-size:.82rem;padding:6px 14px;border-radius:999px;margin-bottom:16px}
.hero h1{font-size:clamp(2rem,4.6vw,3.2rem);line-height:1.12;margin:0 0 12px;letter-spacing:-.02em}
.hero h1 span{background:linear-gradient(90deg,var(--brand),var(--brand2));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p{color:var(--muted);max-width:640px;margin:0 auto 22px;font-size:1.08rem}
.hero-stats{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;color:var(--muted);font-size:.9rem}
/* sections & cards */
.section{padding:26px 0}
.section h2{font-size:1.35rem;margin:0 0 4px}
.section .sub{color:var(--muted);margin:0 0 18px}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:14px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;text-decoration:none;color:var(--text);box-shadow:var(--shadow);transition:transform .12s,border-color .12s;display:block}
.card:hover{transform:translateY(-2px);border-color:var(--brand)}
.card .ico{width:38px;height:38px;border-radius:11px;background:var(--brand-soft);display:grid;place-items:center;font-size:1.15rem;margin-bottom:10px}
.card h3{margin:0 0 4px;font-size:1.02rem}
.card p{margin:0;color:var(--muted);font-size:.9rem}
.card .go{color:var(--brand);font-weight:700;font-size:.88rem;margin-top:10px;display:inline-block}
/* tool page */
.crumbs{padding:22px 0 0;color:var(--muted);font-size:.88rem}
.crumbs a{color:var(--brand);text-decoration:none}
.tool-head h1{margin:6px 0 6px;font-size:clamp(1.6rem,3.4vw,2.3rem);letter-spacing:-.01em}
.tool-head p{color:var(--muted);max-width:680px}
.tool-layout{display:grid;grid-template-columns:1.2fr .8fr;gap:16px;margin:20px auto 30px}
@media(max-width:860px){.tool-layout{grid-template-columns:1fr}}
.panel{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow)}
.panel h2{margin-top:0;font-size:1.05rem}
.field{margin-bottom:14px}
.field label{display:block;font-weight:650;margin-bottom:6px;font-size:.92rem}
.field input,.field select,.field textarea{width:100%;padding:11px 13px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--text);font-size:1rem}
.field-row{display:grid;grid-template-columns:1fr 1fr;gap:12px}
@media(max-width:560px){.field-row{grid-template-columns:1fr}}
.btnrow{display:flex;gap:10px;flex-wrap:wrap;margin-top:6px}
.btn{background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff;border:0;border-radius:10px;padding:12px 20px;font-weight:750;cursor:pointer;font-size:1rem}
.btn:hover{filter:brightness(1.06)}
.btn.ghost{background:var(--surface2);color:var(--text);border:1px solid var(--line)}
.resultbox{background:var(--brand-soft);border:1px dashed var(--brand);border-radius:12px;padding:16px;margin-top:16px}
.resultbox .big{font-size:1.7rem;font-weight:850}
.resultbox table{width:100%;border-collapse:collapse;margin-top:8px;font-size:.95rem}
.resultbox td{padding:6px 4px;border-top:1px solid var(--line)}
.resultbox td:last-child{text-align:right;font-weight:700}
.error{background:#fef2f2;border:1px solid #fecaca;color:#991b1b;border-radius:12px;padding:12px 14px;margin-top:14px}
[data-theme="dark"] .error{background:#2a1215;border-color:#7f1d1d;color:#fecaca}
.formula{background:var(--surface2);border-radius:10px;padding:10px 14px;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:.92rem;overflow-x:auto}
.faq details{border-top:1px solid var(--line);padding:10px 0}
.faq summary{cursor:pointer;font-weight:650}
/* sci pad */
.sci-display{font-size:1.4rem;text-align:right;font-family:ui-monospace,Menlo,monospace;background:var(--bg);border:1px solid var(--line);border-radius:10px;padding:14px;margin-bottom:12px;min-height:58px;overflow-x:auto;white-space:nowrap}
.sci-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:8px}
@media(max-width:560px){.sci-grid{grid-template-columns:repeat(4,1fr)}}
.sci-grid button{padding:12px 6px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--text);font-size:.95rem;cursor:pointer;font-weight:650}
.sci-grid button:hover{border-color:var(--brand)}
.sci-grid button.op{background:var(--brand-soft)}
.sci-grid button.eq{background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff;border:0}
/* ascii */
.ascii-table{width:100%;border-collapse:collapse;font-size:.9rem}
.ascii-table th,.ascii-table td{border:1px solid var(--line);padding:6px 8px;text-align:left}
.ascii-table th{background:var(--surface2)}
.ascii-table td.sym{font-family:ui-monospace,monospace;font-weight:700}
/* color */
.swatch{height:90px;border-radius:12px;border:1px solid var(--line);margin-bottom:12px}
/* notepad */
#pad{width:100%;min-height:340px;resize:vertical;font-size:1rem}
/* footer */
.footer{border-top:1px solid var(--line);margin-top:30px;background:var(--surface)}
.foot-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:20px;padding:34px 20px 10px}
@media(max-width:700px){.foot-grid{grid-template-columns:1fr}}
.footer h4{margin:0 0 8px;font-size:.9rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted)}
.footer a{display:block;color:var(--text);text-decoration:none;padding:3px 0;font-size:.93rem}
.footer a:hover{color:var(--brand)}
.foot-base{display:flex;justify-content:space-between;gap:10px;padding:14px 20px 26px;border-top:1px solid var(--line);margin-top:14px;flex-wrap:wrap;color:var(--muted);font-size:.88rem}
/* ad slot */
.adslot{border:1px dashed var(--line);border-radius:12px;color:var(--muted);text-align:center;padding:14px;font-size:.82rem;margin:18px 0}
/* guides */
.guide{max-width:780px;padding-bottom:30px}
.guide .lead{font-size:1.1rem}
.guide h2{margin:30px 0 10px;font-size:1.3rem;scroll-margin-top:80px}
.guide ol li{margin-bottom:8px}
.guide details{border-top:1px solid var(--line);padding:10px 0}
.guide summary{cursor:pointer;font-weight:650}
.toc{display:flex;gap:8px;flex-wrap:wrap;margin:16px 0}
.toc a{background:var(--brand-soft);color:var(--brand);font-weight:650;font-size:.86rem;padding:6px 13px;border-radius:999px;text-decoration:none}
.guide-cta{display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;margin:20px auto;max-width:780px}
.guide-promo{margin:22px auto;max-width:780px;border-left:4px solid var(--brand)}
.kw-cloud{color:var(--muted);font-size:.92rem}
/* consent banner */
.consent[hidden]{display:none!important}
.consent{position:fixed;left:12px;right:12px;bottom:12px;z-index:60;display:flex;gap:12px;align-items:center;justify-content:space-between;flex-wrap:wrap;background:var(--surface);color:var(--text);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:12px 16px}
.consent p{margin:0;font-size:.9rem}
.consent-btns{display:flex;gap:8px}
.consent button{background:var(--brand);color:#fff;border:0;border-radius:10px;padding:8px 16px;font-weight:650;cursor:pointer}
.consent button.ghost{background:var(--surface2);color:var(--text)}
@media(max-width:560px){.consent{left:8px;right:8px;bottom:8px}.consent-btns{width:100%}.consent-btns button{flex:1}}
/* mobile: scrollable tables + long-word safety */
.table-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch;max-width:100%}
.guide,.kw-cloud,.resultbox{overflow-wrap:break-word}
.langmenu{max-height:min(70vh,400px);overflow-y:auto}
/* small-screen density: header, hero, panels */
@media(max-width:560px){
  .wrap{padding:0 14px}
  .topbar-in{gap:10px;padding:10px 14px}
  .mainnav a{padding:8px 9px;font-size:.92rem}
  .hero{padding:34px 0 18px}
  .panel{padding:16px}
  .guide-cta{margin:16px auto}
  .sci-grid button{padding:12px 4px}
  .resultbox .big{font-size:1.45rem}
  .foot-grid{padding:26px 14px 8px}
}