/* STEP → STL — one stylesheet, no external fonts, no framework. */

:root{
  --paper:#f6f4ef;
  --card:#fffefb;
  --ink:#14181d;
  --ink-2:#4a5461;
  --ink-3:#7b8794;
  --rule:#dcd6c9;
  --rule-2:#eee9df;
  --accent:#c2410c;
  --accent-soft:#fdf1ea;
  --teal:#0f6f6a;
  --warn:#8a5a00;
  --warn-soft:#fdf6e6;
  --mono:ui-monospace,"SFMono-Regular","Cascadia Mono","Segoe UI Mono",Consolas,"Liberation Mono",monospace;
  --sans:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,"Noto Sans",sans-serif;
  --r:10px;
}

*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;background:var(--paper);color:var(--ink);
  font:16px/1.6 var(--sans);
  background-image:linear-gradient(var(--rule-2) 1px,transparent 1px),linear-gradient(90deg,var(--rule-2) 1px,transparent 1px);
  background-size:28px 28px;background-position:-1px -1px;
}
.wrap{max-width:1000px;margin:0 auto;padding:0 20px}
.sr-only{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
code{font:13px/1.5 var(--mono);background:#efece4;padding:1px 5px;border-radius:4px}
a{color:var(--accent)}
a:focus-visible,button:focus-visible,input:focus-visible,label:focus-visible,summary:focus-visible,canvas:focus-visible{outline:3px solid #1f6feb;outline-offset:2px}
.skip-link{position:absolute;left:8px;top:-48px;z-index:10;background:var(--ink);color:var(--paper);font:13px/1 var(--mono);padding:10px 14px;border-radius:0 0 8px 8px;text-decoration:none;transition:top .12s ease}
.skip-link:focus{top:0}

/* ---------- header ---------- */
.site-head{border-bottom:1px solid var(--rule);background:var(--paper)}
.head-row{display:flex;align-items:center;justify-content:space-between;gap:12px;height:56px}
.brand{font:700 15px/1 var(--mono);letter-spacing:.14em;text-transform:uppercase}
.brand .arrow{color:var(--accent);margin:0 4px}
.pill{font:12px/1 var(--mono);letter-spacing:.02em;color:var(--teal);border:1px solid #bfd8d5;background:#eef7f6;padding:6px 10px;border-radius:999px;white-space:nowrap}

/* ---------- tool ---------- */
.tool{padding:30px 0 6px}
h1{font-size:clamp(26px,5.2vw,40px);line-height:1.12;letter-spacing:-.02em;margin:0 0 10px;font-weight:750}
.lede{margin:0 0 22px;color:var(--ink-2);max-width:62ch}

.dropzone{
  display:block;position:relative;cursor:pointer;
  background:var(--card);border:2px dashed #c9c2b1;border-radius:var(--r);
  padding:34px 24px;text-align:center;transition:border-color .15s,background .15s,transform .05s;
}
.dropzone:hover,.dropzone:focus-within{border-color:var(--accent)}
.dropzone.dragging{border-color:var(--accent);background:var(--accent-soft)}
.dropzone.busy{opacity:.65;cursor:progress}
.dropzone input[type=file]{position:absolute;inset:0;width:100%;height:100%;opacity:0;cursor:pointer}
.dropzone:has(input[type=file]:focus-visible){outline:3px solid #1f6feb;outline-offset:2px}
.dz-main{display:block;font-size:18px;font-weight:650;letter-spacing:-.01em}
.dz-sub{display:block;margin-top:8px;font:12px/1.6 var(--mono);color:var(--ink-3)}
.dz-name{display:block;margin-top:14px;font:13px/1.4 var(--mono);color:var(--accent);word-break:break-all}

.engine{margin:14px 0 0;background:var(--card);border:1px solid var(--rule);border-radius:var(--r);padding:12px 14px}
.engine-row{display:flex;align-items:center;gap:9px;font:12.5px/1.5 var(--mono);color:var(--ink-2)}
.dot{width:9px;height:9px;border-radius:50%;background:#c9c2b1;flex:0 0 auto}
.dot[data-state="loading"]{background:var(--warn);animation:pulse 1s infinite}
.dot[data-state="ready"]{background:#2e9e57}
.dot[data-state="failed"]{background:var(--accent)}
@keyframes pulse{50%{opacity:.35}}
.bar{height:4px;background:#e7e2d7;border-radius:2px;margin-top:10px;overflow:hidden}
.bar-fill{display:block;height:100%;width:0;background:var(--teal);transition:width .12s linear}

.controls{margin:14px 0 0;background:var(--card);border:1px solid var(--rule);border-radius:var(--r);padding:16px 18px 14px}
.ctl-group{border:0;margin:0 0 16px;padding:0}
.ctl-group:last-of-type{margin-bottom:6px}
.ctl-group legend{font:11px/1 var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--ink-3);padding:0 0 8px}
.seg{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}
.seg-2{grid-template-columns:repeat(2,minmax(0,1fr))}
.seg input{position:absolute;opacity:0;width:1px;height:1px}
.seg label{
  display:flex;flex-direction:column;gap:2px;padding:10px 11px;cursor:pointer;
  border:1px solid var(--rule);border-radius:8px;background:#fcfaf5;
  font-size:14px;font-weight:620;letter-spacing:-.01em;line-height:1.25;transition:.12s;
}
.seg label span{font:11px/1.3 var(--mono);font-weight:400;color:var(--ink-3)}
.seg input:checked + label{border-color:var(--ink);background:var(--ink);color:#fff}
.seg input:checked + label span{color:#b9c2cd}
.seg input:focus-visible + label{outline:3px solid #1f6feb;outline-offset:2px}
.ctl-note{margin:10px 0 0;font:11.5px/1.5 var(--mono);color:var(--ink-3)}

.live{min-height:20px;margin:12px 0 0;font:13px/1.5 var(--mono);color:var(--teal)}
.error{margin:12px 0 0;background:var(--warn-soft);border:1px solid #e6d3a8;border-radius:8px;padding:12px 14px;font-size:14px;color:var(--warn);overflow-wrap:anywhere}

/* ---------- result ---------- */
.result{margin:18px 0 0;background:var(--card);border:1px solid var(--rule);border-radius:var(--r);padding:18px}
.result-head{display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;margin-bottom:14px}
.out-name{margin:0;font:15px/1.3 var(--mono);font-weight:600;word-break:break-all}
.out-meta{margin:3px 0 0;font:12px/1.4 var(--mono);color:var(--ink-3)}
.btn{
  display:inline-block;background:var(--accent);color:#fff;text-decoration:none;
  font-size:15px;font-weight:650;padding:11px 18px;border-radius:8px;border:0;cursor:pointer;
  white-space:nowrap;
}
.btn:hover{background:#a5360a}
.btn[aria-disabled="true"]{background:#c9c2b1;pointer-events:none}
.btn-ghost{background:var(--card);color:var(--teal);border:1px solid var(--teal)}
.btn-ghost:hover{background:var(--accent-soft);color:var(--accent);border-color:var(--accent)}
.result-actions{display:flex;gap:10px;flex-wrap:wrap}

.canvas-box{position:relative;border:1px solid var(--rule);border-radius:8px;overflow:hidden;background:#10141a}
#preview{display:block;width:100%;height:auto;aspect-ratio:3/2;touch-action:none;cursor:grab}
#preview:active{cursor:grabbing}
.canvas-hint{position:absolute;left:10px;bottom:8px;font:11px/1 var(--mono);color:#8b98a8;pointer-events:none}

.stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:1px;margin:16px 0 0;padding:0;background:var(--rule);border:1px solid var(--rule);border-radius:8px;overflow:hidden}
.stats div{background:var(--card);padding:11px 12px;min-width:0}
.stats dt{font:10.5px/1.4 var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--ink-3)}
.stats dd{margin:3px 0 0;font:14px/1.3 var(--mono);font-weight:600;overflow-wrap:anywhere}
.stats-note{margin:10px 0 0;font:11.5px/1.5 var(--mono);color:var(--ink-3)}

/* ---------- doc ---------- */
.doc{padding:8px 0 40px;border-top:1px solid var(--rule);margin-top:34px}
h2{font-size:clamp(19px,3.4vw,24px);letter-spacing:-.015em;margin:38px 0 12px;font-weight:700}
.doc p,.doc li{max-width:74ch;color:var(--ink-2)}
.doc b{color:var(--ink)}
.steps{margin:0;padding-left:22px}
.steps li{margin-bottom:8px}
.limits{margin:0;padding-left:20px}
.limits li{margin-bottom:9px}

table{border-collapse:collapse;width:100%;font-size:14.5px}
.spec{margin:0 0 6px}
.spec th{width:120px;text-align:left;vertical-align:top;font:11px/1.6 var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--ink-3);padding:11px 12px 11px 0;border-top:1px solid var(--rule)}
.spec td{padding:11px 0;border-top:1px solid var(--rule);color:var(--ink-2)}
.spec tr:first-child th,.spec tr:first-child td{border-top:0}

.table-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch;border:1px solid var(--rule);border-radius:8px;background:var(--card)}
.measured{min-width:560px;font:12.5px/1.5 var(--mono)}
.measured caption{text-align:left;padding:10px 12px;color:var(--ink-3);font-size:11.5px;border-bottom:1px solid var(--rule)}
.measured th,.measured td{padding:8px 12px;text-align:right;white-space:nowrap;border-bottom:1px solid var(--rule-2)}
.measured th:first-child,.measured td:first-child{text-align:left;white-space:normal}
.measured thead th{color:var(--ink-3);font-weight:600;border-bottom:1px solid var(--rule)}
.measured tbody tr:last-child td{border-bottom:0}

details{border-top:1px solid var(--rule);padding:2px 0}
details:last-of-type{border-bottom:1px solid var(--rule)}
summary{cursor:pointer;padding:13px 0;font-weight:640;font-size:16.5px;letter-spacing:-.01em;list-style:none}
summary::-webkit-details-marker{display:none}
summary::before{content:"+";display:inline-block;width:20px;color:var(--accent);font:600 17px/1 var(--mono)}
details[open] summary::before{content:"–"}
details p{margin:0 0 14px 20px}

.src{font:12px/1.5 var(--mono);color:var(--accent);margin:0 0 8px}
.src-list{margin:0 0 18px;padding-left:20px;font-size:14.5px}
.src-list li{margin-bottom:9px}

/* ---------- footer ---------- */
.site-foot{border-top:1px solid var(--rule);background:var(--card);padding:22px 0 34px;font-size:13.5px;color:var(--ink-3)}
.site-foot p{margin:0 0 8px;max-width:80ch}
.site-foot a{color:var(--teal)}
.foot-said{font:11.5px/1.6 var(--mono)}

/* ---------- responsive ---------- */
@media (max-width:760px){
  .stats{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:560px){
  .wrap{padding:0 15px}
  .pill{display:none}
  .tool{padding-top:22px}
  .dropzone{padding:26px 16px}
  .dz-main{font-size:16px}
  .seg{grid-template-columns:1fr}
  .seg label{flex-direction:row;align-items:baseline;gap:8px;flex-wrap:wrap}
  .controls{padding:14px}
  .result{padding:14px}
  .result-head{align-items:flex-start}
  .btn{width:100%;text-align:center}
  .spec th{display:block;width:auto;padding:11px 0 0;border-top:1px solid var(--rule)}
  .spec td{display:block;padding:2px 0 11px;border-top:0}
  .spec tr:first-child th{border-top:0}
  .spec tr th,.spec tr td{border-bottom:0}
  summary{font-size:15.5px}
}
@media (max-width:380px){
  .stats{grid-template-columns:1fr}
}
@media (prefers-reduced-motion:reduce){
  *{animation:none!important;transition:none!important}
}