:root{
  --paper:#FAF8F5; --ink:#16141C; --violet:#6C4CF1; --violet-dark:#5638D8;
  --lilac:#EFEAFE; --console:#17141F; --console2:#211C30; --amber:#FFB224;
  --muted:#5B5766; --line:#E6E1D9; --console-line:#322B47;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{background:var(--paper);color:var(--ink);font-family:'Inter',system-ui,sans-serif;font-size:16px;line-height:1.7}
h1,h2,h3{font-family:'Space Grotesk',sans-serif;line-height:1.15;letter-spacing:-.01em}
a{color:var(--violet);text-decoration:none}
a:hover{text-decoration:underline}
a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid var(--violet);outline-offset:2px}
.wrap{max-width:1120px;margin:0 auto;padding:0 24px}
.mono{font-family:'JetBrains Mono',monospace}

/* ---------- header ---------- */
header.site{position:sticky;top:0;z-index:60;background:rgba(250,248,245,.97);border-bottom:1px solid var(--line)}
.hd{display:flex;align-items:center;gap:24px;height:68px}
.logo{display:flex;align-items:center;gap:11px;color:var(--ink);font-family:'Space Grotesk',sans-serif;font-weight:700;font-size:19px;flex:none}
.logo:hover{text-decoration:none}
.logo-mark{width:38px;height:38px;border-radius:10px;background:var(--violet);display:flex;align-items:flex-end;justify-content:center;gap:3.5px;padding-bottom:9px;flex:none}
.logo-mark i{display:block;width:4.5px;border-radius:2px;background:#fff}
.logo-mark i:nth-child(1){height:20px}.logo-mark i:nth-child(2){height:14px;opacity:.75}.logo-mark i:nth-child(3){height:8px;opacity:.5}
nav.main{display:flex;align-items:center;gap:4px;margin-left:auto}
nav.main a,nav.main .dropbtn{color:var(--ink);font-size:14.5px;font-weight:500;padding:9px 13px;border-radius:999px;white-space:nowrap;background:none;border:none;font-family:'Inter',sans-serif;cursor:pointer;min-height:44px;display:inline-flex;align-items:center}
nav.main a:hover,nav.main .dropbtn:hover{background:var(--lilac);text-decoration:none}
nav.main a.on{background:var(--ink);color:#fff}
nav.main .dropbtn.on{background:var(--ink);color:#fff}
nav.main .dropbtn::after{content:"▾";font-size:11px;margin-left:5px;color:var(--violet)}
nav.main .dropbtn.on::after{color:var(--amber)}
.dropwrap{position:relative}
.dropdown{position:absolute;top:calc(100% + 10px);left:50%;transform:translateX(-50%);background:var(--console);border:1px solid var(--console-line);border-radius:16px;padding:10px;min-width:290px;box-shadow:0 24px 50px -18px rgba(23,20,31,.5);display:none}
.dropdown.open{display:block}
nav.main .dropdown a{display:flex;padding:10px 14px;border-radius:10px;color:#EDEAF4;font-size:14.5px;font-weight:500;min-height:44px;align-items:center}
nav.main .dropdown a:hover{background:var(--console2);color:#fff;text-decoration:none}
nav.main .dropdown a.cur{background:rgba(108,76,241,.25);color:#fff}
.burger{display:none;margin-left:auto;width:46px;height:46px;border:1px solid var(--line);border-radius:10px;background:#fff;font-size:20px;color:var(--ink);cursor:pointer;align-items:center;justify-content:center}
.mmenu{display:none;border-top:1px solid var(--line);background:var(--paper);padding:10px 24px 18px}
.mmenu.open{display:block}
.mmenu a{display:flex;align-items:center;min-height:46px;font-size:16px;font-weight:500;color:var(--ink);border-bottom:1px solid var(--line);padding:4px 2px}
.mmenu a.on{color:var(--violet-dark);font-weight:700}
.mmenu .subbtn{width:100%;display:flex;align-items:center;justify-content:space-between;min-height:46px;font-size:16px;font-weight:500;color:var(--ink);background:none;border:none;border-bottom:1px solid var(--line);font-family:'Inter',sans-serif;cursor:pointer;padding:4px 2px}
.mmenu .sublist{display:none;padding-left:16px}
.mmenu .sublist.open{display:block}
.mmenu .sublist a{font-size:15px}

/* ---------- hero ---------- */
.hero{padding:52px 0 8px;text-align:center}
.eyebrow{display:inline-block;background:var(--lilac);color:var(--violet-dark);font-size:12.5px;font-weight:700;letter-spacing:.09em;text-transform:uppercase;padding:6px 14px;border-radius:999px}
.hero h1{font-size:44px;font-weight:700;margin:18px auto 12px;max-width:780px}
.hero p.sub{font-size:18.5px;color:var(--muted);max-width:660px;margin:0 auto;line-height:1.6}
.hero p.sub strong{color:var(--ink)}
.pagehead{padding:44px 0 4px;text-align:center}
.pagehead h1{font-size:40px;font-weight:700;margin:16px auto 10px;max-width:760px}
.pagehead p.sub{font-size:18px;color:var(--muted);max-width:640px;margin:0 auto;line-height:1.6}
.pagehead p.sub strong{color:var(--ink)}

/* ---------- console / tools ---------- */
.console{background:var(--console);border-radius:22px;padding:30px 32px 34px;margin:34px auto 0;max-width:920px;color:#EDEAF4;box-shadow:0 24px 60px -18px rgba(23,20,31,.45);text-align:left}
.console-top{display:flex;align-items:center;justify-content:space-between;gap:12px;border-bottom:1px solid var(--console-line);padding-bottom:16px;margin-bottom:20px}
.console-top .ct{font-family:'Space Grotesk',sans-serif;font-weight:600;font-size:14px;letter-spacing:.14em;text-transform:uppercase;color:#B9B2CC}
.dots{display:flex;gap:7px}.dots i{width:11px;height:11px;border-radius:50%;background:#3A3352;display:block}.dots i:first-child{background:var(--violet)}
.bpm-row{display:flex;flex-wrap:wrap;gap:18px;align-items:center;justify-content:center}
.bpm-box{display:flex;align-items:center;gap:12px}
.bpm-box label,.fld label{font-size:13px;font-weight:600;letter-spacing:.1em;text-transform:uppercase;color:#B9B2CC}
.bpm-input{display:flex;align-items:baseline;gap:6px;background:var(--console2);border:1px solid var(--console-line);border-radius:12px;padding:8px 16px}
.bpm-input input{width:96px;background:none;border:none;font-family:'JetBrains Mono',monospace;font-size:34px;font-weight:600;color:var(--amber);line-height:1;text-align:right}
.bpm-input input:focus-visible{outline:none}
.bpm-input .unit{font-size:13px;color:#B9B2CC;font-weight:600}
input[type=range].bpm-range{flex:1;min-width:180px;max-width:340px;-webkit-appearance:none;appearance:none;height:6px;border-radius:3px;background:#3A3352;cursor:pointer}
input[type=range].bpm-range::-webkit-slider-thumb{-webkit-appearance:none;width:26px;height:26px;border-radius:50%;background:#fff;border:6px solid var(--violet);cursor:pointer}
input[type=range].bpm-range::-moz-range-thumb{width:16px;height:16px;border-radius:50%;background:#fff;border:6px solid var(--violet);cursor:pointer}
.tapbtn{background:var(--violet);color:#fff;border:none;font-family:'Inter',sans-serif;font-weight:600;font-size:15px;padding:13px 22px;border-radius:12px;cursor:pointer;min-height:48px}
.tapbtn:hover{background:var(--violet-dark)}
.tapbtn:active{transform:scale(.97)}
.bpm-scale{display:flex;justify-content:space-between;max-width:640px;margin:10px auto 0;font-size:11.5px;color:#8B84A3;font-family:'JetBrains Mono',monospace}
.fldrow{display:flex;flex-wrap:wrap;gap:16px;justify-content:center;margin-top:6px}
.fld{display:flex;flex-direction:column;gap:7px}
.fld select,.fld input[type=number],.fld input[type=text]{background:var(--console2);border:1px solid var(--console-line);border-radius:11px;color:#EDEAF4;font-family:'Inter',sans-serif;font-size:15.5px;padding:11px 14px;min-height:48px}
.fld select:focus-visible,.fld input:focus-visible{outline:2px solid var(--violet);outline-offset:1px}
.unit-toggle{display:inline-flex;background:var(--console2);border:1px solid var(--console-line);border-radius:11px;overflow:hidden}
.unit-toggle button{background:none;border:none;color:#B9B2CC;font-family:'Inter',sans-serif;font-weight:600;font-size:14px;padding:12px 18px;cursor:pointer;min-height:48px}
.unit-toggle button.on{background:var(--violet);color:#fff}
.readouts{display:flex;flex-wrap:wrap;gap:14px;justify-content:center;margin-top:22px}
.ro{background:var(--console2);border:1px solid var(--console-line);border-radius:14px;padding:14px 22px;text-align:center;min-width:158px}
.ro .rl{font-size:11.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:#B9B2CC}
.ro .rv{font-family:'JetBrains Mono',monospace;font-size:27px;font-weight:600;color:var(--amber);line-height:1.25}
.ro .rv small{font-size:14px;color:#B9B2CC}
.tbl-title{font-family:'Space Grotesk',sans-serif;font-size:16.5px;font-weight:600;margin:28px 0 10px;display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.tbl-title span{font-size:11px;background:var(--violet);color:#fff;border-radius:5px;padding:2.5px 8px;letter-spacing:.08em;font-family:'Inter',sans-serif;font-weight:700}
.tbl-scroll{overflow-x:auto;border:1px solid var(--console-line);border-radius:14px}
table.calc{border-collapse:collapse;width:100%;min-width:520px;font-size:15px}
table.calc th{background:var(--console2);color:#B9B2CC;font-size:12px;letter-spacing:.09em;text-transform:uppercase;font-weight:600;text-align:left;padding:11px 16px}
table.calc td{padding:11px 16px;border-top:1px solid var(--console-line);color:#EDEAF4;white-space:nowrap}
table.calc td.num,table.calc th.num{font-family:'JetBrains Mono',monospace;color:var(--amber);font-size:14.5px}
table.calc td.size{font-weight:600}
table.calc td.size small{display:block;font-weight:400;color:#8B84A3;font-size:12.5px}
table.calc tr.hl td{background:rgba(108,76,241,.13)}
table.calc tr.pick{cursor:pointer}
table.calc tr.pick:hover td{background:rgba(108,76,241,.1)}
table.calc th:first-child,table.calc td:first-child{position:sticky;left:0;background:var(--console);z-index:1}
table.calc th:first-child{background:var(--console2)}
table.calc tr.hl td:first-child{background:#241D3D}
.console-note{margin-top:16px;font-size:13.5px;color:#8B84A3;text-align:center;line-height:1.6}
.console-note b{color:#EDEAF4;font-weight:600}
.console-note a{color:#B7A6FF}
.big-tap{width:100%;padding:22px;font-size:19px;border-radius:14px;margin-top:4px}

/* ---------- TOC ---------- */
.toc{max-width:920px;margin:30px auto 0;background:#fff;border:1px solid var(--line);border-radius:14px;padding:16px 22px;display:flex;flex-wrap:wrap;gap:8px 18px;align-items:center;text-align:left}
.toc b{font-family:'Space Grotesk',sans-serif;font-size:14px;letter-spacing:.06em;text-transform:uppercase}
.toc a{font-size:14.5px;font-weight:500}
.toc a::before{content:"§ ";color:#C9C2B4}

/* ---------- sections / prose ---------- */
section.block{padding:52px 0 6px;max-width:920px;margin:0 auto}
section.block.wide{max-width:1120px}
section.block h2{font-size:30px;font-weight:700;margin-bottom:10px;scroll-margin-top:90px}
section.block h3{font-size:20px;font-weight:600;margin:26px 0 8px}
section.block p{color:#33303E;margin-bottom:14px;max-width:760px}
section.block p.lede{color:var(--muted);max-width:720px;margin-bottom:24px}
section.block ul{color:#33303E;margin:0 0 16px 22px;max-width:740px}
section.block li{margin-bottom:7px}
.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:22px 22px 18px;display:block;color:var(--ink);transition:.15s}
.card:hover{border-color:var(--violet);box-shadow:0 10px 28px -14px rgba(108,76,241,.35);transform:translateY(-2px);text-decoration:none}
.card .ic{width:42px;height:42px;border-radius:11px;background:var(--lilac);display:flex;align-items:center;justify-content:center;margin-bottom:12px}
.card .ic svg{width:22px;height:22px;stroke:var(--violet-dark);fill:none;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.card h3{font-size:18px;margin:0 0 5px}
.card p{font-size:14.5px;color:var(--muted);line-height:1.55;margin:0}
.card .go{font-size:13.5px;font-weight:600;color:var(--violet);margin-top:10px;display:inline-block}
.formula{background:var(--console);color:#EDEAF4;border-radius:12px;padding:18px 20px;font-family:'JetBrains Mono',monospace;font-size:15.5px;margin:14px 0;line-height:1.9;overflow-x:auto}
.formula .a{color:var(--amber)} .formula .v{color:#B7A6FF}
.example{background:var(--lilac);border-radius:12px;padding:16px 20px;font-size:15.5px;margin:14px 0;color:#33303E}
.example b{font-family:'Space Grotesk',sans-serif;color:var(--ink)}
.panel{background:#fff;border:1px solid var(--line);border-radius:16px;padding:26px}
.panel h3{margin-top:0}
.tbl-scroll.light{border:1px solid var(--line);border-radius:14px;margin:16px 0}
table.data{border-collapse:collapse;width:100%;min-width:480px;font-size:15px;background:#fff}
table.data th{background:var(--lilac);color:var(--ink);font-size:12.5px;letter-spacing:.07em;text-transform:uppercase;font-weight:700;text-align:left;padding:11px 16px}
table.data td{padding:10px 16px;border-top:1px solid var(--line);color:#33303E;white-space:nowrap}
table.data td.n,table.data th.n{font-family:'JetBrains Mono',monospace;color:var(--violet-dark);font-size:14.5px}
table.data th:first-child,table.data td:first-child{position:sticky;left:0;background:#fff;z-index:1}
table.data th:first-child{background:var(--lilac)}

/* ---------- FAQ / sources ---------- */
.faq{max-width:820px}
details{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px 22px;margin-bottom:12px;text-align:left}
details summary{font-family:'Space Grotesk',sans-serif;font-weight:600;font-size:17px;cursor:pointer;list-style:none;display:flex;justify-content:space-between;gap:14px;min-height:28px;align-items:center}
details summary::-webkit-details-marker{display:none}
details summary::after{content:"+";color:var(--violet);font-size:22px;line-height:1;flex:none}
details[open] summary::after{content:"–"}
details p{color:var(--muted);margin-top:10px;font-size:15.5px;max-width:none}
.sources{max-width:820px;background:#fff;border:1px solid var(--line);border-radius:14px;padding:20px 24px;margin-top:26px;text-align:left}
.sources .sh{font-family:'Space Grotesk',sans-serif;font-size:14px;letter-spacing:.06em;text-transform:uppercase;display:block;margin-bottom:8px;font-weight:700}
.sources p,.sources li{font-size:15px;color:var(--muted)}
.sources ul{margin-left:20px}
.sources a{font-weight:500}

/* ---------- chart page ---------- */
.printbar{max-width:920px;margin:26px auto 0;display:flex;justify-content:center}
.printbtn{background:var(--violet);color:#fff;border:none;font-family:'Inter',sans-serif;font-weight:600;font-size:16px;padding:14px 28px;border-radius:12px;cursor:pointer;min-height:52px;display:inline-flex;align-items:center;gap:10px}
.printbtn:hover{background:var(--violet-dark)}
.printbtn svg{width:19px;height:19px;stroke:#fff;fill:none;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.chartwrap{max-width:920px;margin:22px auto 0}
.chartwrap .tbl-scroll.light{margin:0}
table.data.chart td.n,table.data.chart th.n{text-align:right}
table.data.chart td:first-child{font-family:'JetBrains Mono',monospace;color:var(--violet-dark);font-weight:600}

/* ---------- footer ---------- */
footer.site{background:var(--ink);color:#CFCADF;margin-top:64px}
.ft{display:grid;grid-template-columns:1.5fr 1fr 1fr 1.1fr;gap:36px;padding:52px 0 36px}
.ft .flogo{display:flex;align-items:center;gap:11px;font-family:'Space Grotesk',sans-serif;font-weight:700;font-size:18px;color:#fff;margin-bottom:12px}
.ft p{font-size:14.5px;line-height:1.6;color:#A49FB8}
.ft .built{margin-top:16px;font-size:14px;color:#A49FB8}
.ft .built a{color:#fff;font-weight:600}
.profiles{display:flex;gap:8px;margin-top:14px;flex-wrap:wrap}
.profiles a{border:1px solid #34304A;color:#CFCADF;font-size:13px;font-weight:500;padding:7px 12px;border-radius:999px;min-height:36px;display:inline-flex;align-items:center}
.profiles a:hover{color:#fff;text-decoration:none;border-color:var(--violet)}
.ft .fth{font-family:'Space Grotesk',sans-serif;color:#fff;font-size:13.5px;letter-spacing:.1em;text-transform:uppercase;margin-bottom:14px;font-weight:600}
.ft ul{list-style:none}
.ft li{margin-bottom:9px}
.ft li a{color:#A49FB8;font-size:14.5px}
.ft li a:hover{color:#fff}
.ft .mail{color:#fff;font-weight:600}
.copy{border-top:1px solid #2A2640;padding:20px 0 26px;font-size:13.5px;color:#8B84A3;display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap}

/* ---------- back to top ---------- */
.totop{position:fixed;right:20px;bottom:20px;width:46px;height:46px;border-radius:50%;background:var(--violet);color:#fff;border:none;font-size:19px;cursor:pointer;box-shadow:0 10px 24px -8px rgba(23,20,31,.5);opacity:0;pointer-events:none;transition:opacity .2s;z-index:55;display:flex;align-items:center;justify-content:center}
.totop.show{opacity:1;pointer-events:auto}
.totop:hover{background:var(--violet-dark)}

/* ---------- responsive ---------- */
@media (max-width:900px){ .cards{grid-template-columns:repeat(2,1fr)} .ft{grid-template-columns:1fr 1fr} }
@media (max-width:860px){ nav.main{display:none}.burger{display:inline-flex} }
@media (max-width:640px){
  .hero{padding:38px 0 4px}.hero h1{font-size:33px}.hero p.sub{font-size:16.5px}
  .pagehead{padding:32px 0 2px}.pagehead h1{font-size:30px}.pagehead p.sub{font-size:16.5px}
  .console{padding:22px 16px 26px;border-radius:18px;margin-top:26px}
  .bpm-input input{font-size:29px;width:80px}
  .cards{grid-template-columns:1fr}
  section.block{padding:42px 0 4px}section.block h2{font-size:26px}
  .ft{grid-template-columns:1fr;gap:28px;padding:40px 0 28px}
  body{text-align:center}
  .hd,.toc,.card,.panel,details,.sources,.ft,.copy,.console,section.block{text-align:left}
  .hero,.pagehead,.console-note,.printbar{text-align:center}
  .ro{min-width:132px}
}

/* ---------- print (chart) ---------- */
@media print{
  header.site,footer.site,.totop,.printbar,.toc,.mmenu{display:none !important}
  body{background:#fff;text-align:left}
  .chartwrap{max-width:none;margin:0}
  .tbl-scroll{overflow:visible !important;border:none}
  table.data{min-width:0;width:100%}
  table.data th,table.data td{color:#000 !important;background:#fff !important;white-space:normal}
  table.data th:first-child,table.data td:first-child{position:static}
  section.block{max-width:none;padding:0}
}