:root{
  --bg:#f6f7f9;
  --panel:#ffffff;
  --ink:#16181d;
  --ink-soft:#5a6070;
  --line:#e2e5ea;
  --line-strong:#c9cfd8;
  --accent:#2f6bff;
  --accent-ink:#ffffff;
  --ok:#0f9d58;
  --radius:12px;
  --shadow:0 1px 2px rgba(16,20,30,.06),0 8px 24px rgba(16,20,30,.06);
}

*{box-sizing:border-box}
/* the workspace must stay hidden until an image is loaded: a bare `hidden`
   attribute loses to the .workspace display rule below */
[hidden]{display:none !important}
html,body{margin:0;padding:0}
body{
  background:var(--bg);
  color:var(--ink);
  font:15px/1.5 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,"Noto Sans SC",sans-serif;
  -webkit-text-size-adjust:100%;
}
a{color:var(--accent)}

/* ---------- header ---------- */
.top{padding:26px 20px 4px;max-width:1180px;margin:0 auto}
.top h1{margin:0;font-size:clamp(24px,4.4vw,34px);letter-spacing:-.02em}
.sub{margin:6px 0 0;color:var(--ink-soft);font-size:15px}

.privacy{
  max-width:1180px;margin:14px auto 0;padding:11px 14px;
  display:flex;align-items:center;gap:9px;
  background:#eef4ff;border:1px solid #d3e0ff;border-radius:var(--radius);
  color:#1f3d7a;font-size:14px;font-weight:500;
}
.privacy .dot{width:9px;height:9px;border-radius:50%;background:var(--ok);flex:0 0 auto}

main{max-width:1180px;margin:0 auto;padding:18px 20px 40px}

/* ---------- drop zone ---------- */
.drop{
  background:var(--panel);border:2px dashed var(--line-strong);border-radius:16px;
  padding:46px 20px;text-align:center;cursor:pointer;transition:.15s;
  box-shadow:var(--shadow);
}
.drop:hover,.drop:focus-visible{border-color:var(--accent);outline:none}
.drop.over{border-color:var(--accent);background:#f2f6ff}
.drop-inner{display:flex;flex-direction:column;align-items:center;gap:6px}
.drop-icon{width:34px;height:34px;fill:none;stroke:var(--accent);stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round;margin-bottom:4px}
.drop strong{font-size:17px}
.drop span{color:var(--ink-soft);font-size:13.5px}

/* ---------- workspace ---------- */
.workspace{display:grid;grid-template-columns:minmax(0,1.65fr) minmax(300px,1fr);gap:18px;align-items:start}
.pane{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:14px;box-shadow:var(--shadow);min-width:0}
.pane-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:10px}
.pane-head h2{margin:0;font-size:15px;letter-spacing:.01em}
.pane-actions{display:flex;gap:6px}

.stage{position:relative;background:
  linear-gradient(45deg,#eceef2 25%,transparent 25%,transparent 75%,#eceef2 75%),
  linear-gradient(45deg,#eceef2 25%,transparent 25%,transparent 75%,#eceef2 75%);
  background-size:18px 18px;background-position:0 0,9px 9px;
  border:1px solid var(--line);border-radius:10px;overflow:hidden;
  display:flex;align-items:center;justify-content:center;min-height:220px;
  touch-action:none;cursor:grab;
}
.stage.dragging{cursor:grabbing}
.canvas-box{position:relative;display:inline-block;max-width:100%;line-height:0}
.canvas-box canvas{display:block;max-width:100%;height:auto}
#original{position:absolute;inset:0;width:100%;height:100%}
#view{position:relative}
#overlay{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}
.hint{position:absolute;left:10px;bottom:10px;background:rgba(22,24,29,.72);color:#fff;
  font-size:12px;padding:4px 9px;border-radius:999px;pointer-events:none;opacity:1;transition:opacity .4s}
.hint.gone{opacity:0}

.loupe-wrap{margin-top:12px}
.loupe-head{display:flex;justify-content:space-between;align-items:center;font-size:12.5px;color:var(--ink-soft);margin-bottom:6px}
.loupe-legend{display:flex;align-items:center;gap:6px}
.sw{width:10px;height:10px;border-radius:2px;display:inline-block;border:1px solid var(--line-strong)}
.sw.before{background:#f0b3b3}
.sw.after{background:#b6e3c6}
#loupe{width:100%;max-width:100%;display:block;border:1px solid var(--line);border-radius:10px;background:#fff}
.meta{margin:10px 0 0;font-size:12.5px;color:var(--ink-soft)}

/* ---------- controls ---------- */
.field{margin-bottom:14px}
.field.two{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.field label{display:flex;justify-content:space-between;align-items:baseline;gap:8px;font-size:13px;font-weight:600;margin-bottom:5px}
.field output{font-variant-numeric:tabular-nums;font-weight:500;color:var(--ink-soft)}
.field small{display:block;color:var(--ink-soft);font-size:12px;margin-top:5px;line-height:1.45}
select,input[type=range]{width:100%}
select{padding:8px 10px;border:1px solid var(--line-strong);border-radius:9px;background:#fff;font:inherit;font-size:14px}
input[type=range]{-webkit-appearance:none;appearance:none;height:30px;background:transparent;margin:0}
input[type=range]::-webkit-slider-runnable-track{height:5px;border-radius:3px;background:#dfe3ea}
input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;width:22px;height:22px;border-radius:50%;
  background:#fff;border:2px solid var(--accent);margin-top:-9px;box-shadow:0 1px 4px rgba(0,0,0,.18);cursor:pointer}
input[type=range]::-moz-range-track{height:5px;border-radius:3px;background:#dfe3ea}
input[type=range]::-moz-range-thumb{width:20px;height:20px;border-radius:50%;background:#fff;border:2px solid var(--accent);cursor:pointer}

.row-btns{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:14px}
button{font:inherit;font-size:14px;font-weight:600;padding:11px 14px;border-radius:10px;cursor:pointer;border:1px solid transparent;min-height:44px}
button.primary{background:var(--accent);color:var(--accent-ink)}
button.primary:hover{filter:brightness(1.07)}
button.ghost{background:#fff;color:var(--ink);border-color:var(--line-strong)}
button.ghost:hover{background:#f4f6fa}
button:disabled{opacity:.5;cursor:not-allowed}
hr{border:0;border-top:1px solid var(--line);margin:18px 0}

.tiny{font-size:12px;color:var(--ink-soft);line-height:1.5;margin:0}
.err{margin:16px 0 0;padding:11px 14px;border-radius:10px;background:#fdecec;border:1px solid #f5c2c2;color:#8a2020;font-size:13.5px}

.bottom{max-width:1180px;margin:0 auto;padding:0 20px 40px;color:var(--ink-soft)}
.bottom p{margin:0 0 6px;font-size:12.5px}

/* ---------- the two copy sections below the tool ---------- */
.explain{margin-top:18px;background:var(--panel);border:1px solid var(--line);
  border-radius:var(--radius);padding:16px 18px;box-shadow:var(--shadow)}
.explain+.explain{margin-top:14px}
.explain h2{margin:0 0 8px;font-size:16px;letter-spacing:-.01em}
.explain p{margin:0 0 10px;color:var(--ink-soft);font-size:14px;line-height:1.62}
.explain p:last-child{margin-bottom:0}
.explain strong{color:var(--ink);font-weight:600}
.explain code{font:13px/1.45 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  background:#f1f3f7;border:1px solid var(--line);border-radius:5px;padding:1px 5px;color:#2a3040;
  overflow-wrap:break-word}

/* ---------- footer nav (every page) ---------- */
.foot-nav{display:flex;flex-wrap:wrap;gap:8px 18px;margin:0 0 14px;padding:0}
.foot-nav a{font-size:13px;font-weight:600;text-decoration:none;padding-bottom:1px;
  border-bottom:1px solid transparent}
.foot-nav a:hover{border-bottom-color:currentColor}
.foot-nav a[aria-current=page]{color:var(--ink);border-bottom-color:var(--line-strong)}

/* ---------- the static pages (about / privacy / contact) ---------- */
.top .home{display:inline-block;margin-bottom:2px;font-size:14px;font-weight:600;text-decoration:none}
.top .home::before{content:"\2190\00a0"}
.page{max-width:780px;margin:0 auto;padding:6px 20px 44px}
.page h2{margin:28px 0 8px;font-size:18px;letter-spacing:-.01em}
.page h2:first-of-type{margin-top:10px}
.page p,.page li{color:var(--ink-soft);font-size:15px;line-height:1.68}
.page p{margin:0 0 12px}
.page ul{margin:0 0 12px;padding-left:22px}
.page li{margin-bottom:6px}
.page strong{color:var(--ink);font-weight:600}
.page a{overflow-wrap:break-word}
.page .lead{font-size:16.5px;color:var(--ink);line-height:1.6}
.note{margin-top:24px;padding:13px 15px;background:var(--panel);border:1px solid var(--line);
  border-radius:var(--radius);font-size:13.5px;color:var(--ink-soft);line-height:1.6}
.mail{display:inline-block;font-size:17px;font-weight:600;text-decoration:none;
  padding:10px 16px;border-radius:10px;background:var(--panel);border:1px solid var(--line-strong)}
.mail:hover{border-color:var(--accent)}

/* ---------- mobile ---------- */
@media (max-width:880px){
  .workspace{grid-template-columns:1fr}
  .drop{padding:34px 16px}
  .field.two{grid-template-columns:1fr}
  .top{padding-top:18px}
}
@media (max-width:560px){
  .page h2{font-size:17px}
  .page p,.page li{font-size:15px}
  .foot-nav{gap:8px 14px}
}