:root{
  --bg:#ffffff;
  --surface:#f7f8fa;
  --line:#e3e6ec;
  --line-strong:#d0d5df;
  --ink:#16181d;
  --ink-2:#4a505c;
  --ink-3:#767d8b;
  --accent:#2f6bff;
  --accent-ink:#ffffff;
  --ok:#12805c;
  --radius:14px;
  --shadow:0 1px 2px rgba(16,18,23,.05), 0 8px 24px rgba(16,18,23,.06);
}

*{box-sizing:border-box}

html,body{margin:0;padding:0}

body{
  background:var(--bg);
  color:var(--ink);
  font:16px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  -webkit-font-smoothing:antialiased;
  -webkit-text-size-adjust:100%;
}

.wrap{max-width:1100px;margin:0 auto;padding:0 20px}

/* ---------- top bar ---------- */
.bar{
  border-bottom:1px solid var(--line);
  background:var(--bg);
  position:sticky;top:0;z-index:20;
}
.bar .wrap,
.bar{
  display:flex;align-items:center;justify-content:space-between;
}
.bar>.brand{margin-left:20px}
.bar>.bar-nav{margin-right:20px}
.brand{
  font-weight:700;font-size:16px;letter-spacing:-.2px;
  color:var(--ink);text-decoration:none;padding:14px 0;
}
.brand .tld{color:var(--ink-3);font-weight:500}
.bar-nav{display:flex;gap:18px}
.bar-nav a{
  color:var(--ink-2);text-decoration:none;font-size:14px;
}
.bar-nav a:hover{color:var(--accent)}

/* ---------- heading ---------- */
h1{
  font-size:clamp(28px,5vw,40px);
  line-height:1.15;letter-spacing:-.8px;
  margin:34px 0 6px;font-weight:800;
}
.tagline{
  margin:0 0 22px;color:var(--ink-2);
  font-size:clamp(15px,2.2vw,17px);max-width:62ch;
}

/* ---------- tool ---------- */
.tool{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:16px;
  align-items:start;
}
.pane{
  border:1px solid var(--line);
  border-radius:var(--radius);
  background:var(--bg);
  padding:14px;
  box-shadow:var(--shadow);
}

/* drop zone */
.drop{
  border:2px dashed var(--line-strong);
  border-radius:12px;
  background:var(--surface);
  min-height:260px;
  display:flex;align-items:center;justify-content:center;
  cursor:pointer;text-align:center;padding:18px;
  transition:border-color .15s, background .15s;
  outline:none;
}
.drop:hover{border-color:var(--accent)}
.drop:focus-visible{border-color:var(--accent);box-shadow:0 0 0 3px rgba(47,107,255,.16)}
.drop.over{border-color:var(--accent);background:#eef3ff}
.drop-empty{color:var(--ink-2)}
.drop .ico{color:var(--ink-3);margin-bottom:6px}
.drop-title{margin:0 0 4px;font-weight:650;color:var(--ink);font-size:16px}
.drop-hint{margin:0;font-size:14px}
.drop-fmt{margin:8px 0 0;font-size:12.5px;color:var(--ink-3);letter-spacing:.4px}
.aslink{color:var(--accent);font-weight:600}
kbd{
  font:inherit;font-size:12.5px;background:#fff;border:1px solid var(--line-strong);
  border-bottom-width:2px;border-radius:5px;padding:1px 5px;color:var(--ink-2);
}
.drop-filled{padding:0;line-height:0}
.drop-filled img{
  max-width:100%;max-height:300px;border-radius:10px;display:block;margin:0 auto;
}

/* controls */
.controls{
  display:flex;gap:10px;align-items:flex-end;flex-wrap:wrap;margin-top:12px;
}
.fld{flex:1 1 130px;min-width:120px;display:flex;flex-direction:column;gap:5px}
.fld-l{font-size:12.5px;font-weight:650;color:var(--ink-2);letter-spacing:.2px}
select{
  font:inherit;font-size:15px;color:var(--ink);
  padding:9px 10px;border:1px solid var(--line-strong);border-radius:9px;
  background:#fff;width:100%;min-height:42px;-webkit-appearance:none;appearance:none;
  background-image:linear-gradient(45deg,transparent 50%,var(--ink-3) 50%),linear-gradient(135deg,var(--ink-3) 50%,transparent 50%);
  background-position:calc(100% - 16px) 50%,calc(100% - 11px) 50%;
  background-size:5px 5px,5px 5px;background-repeat:no-repeat;
}
select:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(47,107,255,.16)}

.btn{
  font:inherit;font-weight:650;font-size:15px;
  padding:10px 16px;min-height:42px;
  border:1px solid var(--accent);border-radius:9px;
  background:var(--accent);color:var(--accent-ink);cursor:pointer;
}
.btn:hover:not(:disabled){filter:brightness(1.06)}
.btn:disabled{opacity:.45;cursor:not-allowed}
.btn.ghost{background:#fff;color:var(--ink-2);border-color:var(--line-strong)}
.btn.ghost:hover{color:var(--ink);border-color:var(--ink-3)}

/* output */
.out-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:10px}
.out-title{font-size:12.5px;font-weight:700;color:var(--ink-2);letter-spacing:.5px;text-transform:uppercase}
#out{
  width:100%;font:15px/1.65 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  color:var(--ink);background:var(--surface);
  border:1px solid var(--line);border-radius:10px;
  padding:14px;resize:vertical;min-height:190px;
  overflow-wrap:anywhere;word-break:break-word;
}
#out:focus{outline:none;border-color:var(--accent)}
.copied{margin:8px 0 0;font-size:13.5px;color:var(--ok);font-weight:600}

/* facts panel */
.facts{margin-top:14px;border-top:1px solid var(--line);padding-top:12px}
.facts-h{margin:0 0 8px;font-size:12.5px;font-weight:700;color:var(--ink-2);letter-spacing:.5px;text-transform:uppercase}
.facts-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:6px 12px;font-size:13.5px;color:var(--ink-2)}
.facts-grid div{display:flex;justify-content:space-between;gap:8px}
.facts-grid b{font-weight:650;color:var(--ink);text-align:right;overflow-wrap:anywhere}
.swatches{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}
.sw{display:flex;align-items:center;gap:6px;border:1px solid var(--line);border-radius:999px;padding:3px 9px 3px 3px;font-size:12.5px;color:var(--ink-2)}
.sw i{width:16px;height:16px;border-radius:50%;display:block;border:1px solid rgba(0,0,0,.12)}

/* ---------- docs ---------- */
.doc{margin-top:46px;padding-top:26px;border-top:1px solid var(--line)}
.doc h2{font-size:22px;letter-spacing:-.3px;margin:0 0 12px}
.doc h3{font-size:16.5px;margin:22px 0 8px}
.doc p{margin:0 0 12px;color:var(--ink-2);max-width:80ch}
.doc ul{margin:0 0 12px;padding-left:20px;color:var(--ink-2)}
.doc li{margin-bottom:5px}
.steps{margin:0 0 14px;padding-left:20px;color:var(--ink-2)}
.steps li{margin-bottom:7px}
.note{font-size:14.5px;color:var(--ink-3)}
.cols{display:grid;grid-template-columns:1fr 1fr;gap:24px}

details{border-bottom:1px solid var(--line);padding:13px 0}
details summary{
  cursor:pointer;font-weight:650;font-size:16px;list-style:none;
  display:flex;justify-content:space-between;gap:12px;align-items:flex-start;
}
details summary::-webkit-details-marker{display:none}
details summary::after{content:"+";color:var(--ink-3);font-weight:400;font-size:20px;line-height:1}
details[open] summary::after{content:"–"}
details p{margin:10px 0 2px;color:var(--ink-2);max-width:80ch}

.foot{border-top:1px solid var(--line);margin-top:46px;padding:22px 0 40px}
.foot p{margin:0;color:var(--ink-3);font-size:14px}

/* ---------- mobile ---------- */
@media (max-width:880px){
  .tool{grid-template-columns:1fr}
  .cols{grid-template-columns:1fr;gap:8px}
}
@media (max-width:560px){
  .wrap{padding:0 14px}
  .bar>.brand{margin-left:14px}
  .bar>.bar-nav{margin-right:14px;gap:13px}
  .bar-nav a{font-size:13px}
  h1{margin-top:24px}
  .drop{min-height:210px}
  .pane{padding:12px}
  .controls{gap:8px}
  .fld{flex:1 1 100%}
  .btn{width:100%}
  .out-head .btn{width:auto}
  .facts-grid{grid-template-columns:1fr}
}