*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--fg);font:16px/1.6 var(--font);overflow-x:hidden}
h1,h2,h3,.h2{font-family:var(--head);line-height:1.2;margin:0 0 .5em}
h1{font-size:clamp(1.7rem,4.5vw,2.5rem);letter-spacing:-.01em}
h2,.h2{font-size:1.35rem;margin-top:1.6em}
h3{font-size:1.08rem;margin-top:1.2em}
a{color:var(--accent)}
img,canvas,video{max-width:100%}
.wrap{max-width:960px;margin:0 auto;padding:0 16px}
.skip{position:absolute;left:-999px}.skip:focus{left:8px;top:8px;background:var(--card);padding:8px;z-index:9}
.muted{color:var(--muted)}.small{font-size:.86rem}
.site-header{border-bottom:1px solid var(--border);background:var(--card)}
.header-bar .site-header{background:var(--accent);border:0}
.header-bar .site-header a{color:var(--accent-fg)}
.header-bar .site-header .logo{background:var(--accent-fg);color:var(--accent)}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px;min-height:58px;flex-wrap:wrap}
.brand{font-weight:700;text-decoration:none;color:var(--fg);display:flex;align-items:center;gap:8px;font-family:var(--head)}
.logo{display:inline-grid;place-items:center;width:30px;height:30px;border-radius:calc(var(--radius) / 1.5);background:var(--accent);color:var(--accent-fg);font-size:.95rem}
.site-header nav{display:flex;gap:16px;font-size:.92rem}
.site-header nav a{text-decoration:none;color:var(--muted)}
.hero{padding:28px 0 12px}
.header-plain .hero{text-align:center}
.lead{font-size:1.1rem;color:var(--muted);margin:0;max-width:720px}
.header-plain .lead{margin:0 auto}
.crumbs{font-size:.88rem;color:var(--muted);padding-top:16px}
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:20px}
.tool{margin:8px 0 6px;box-shadow:0 1px 2px rgb(0 0 0 / .04),0 8px 24px -12px rgb(0 0 0 / .12)}
.privacy-note{font-size:.85rem;color:var(--muted);margin:4px 2px 24px}
.content{max-width:760px}
.content.card,.prose{max-width:760px;margin:24px auto}
.content p,.content li{color:var(--fg)}
.steps li{margin:.3em 0}
details{border:1px solid var(--border);border-radius:var(--radius);background:var(--card);padding:0 16px;margin:8px 0}
summary{cursor:pointer;font-weight:600;padding:12px 0}
details>div{padding-bottom:12px}
table{border-collapse:collapse;width:100%;font-size:.94rem}
th,td{border-bottom:1px solid var(--border);padding:7px 8px;text-align:left;vertical-align:top}
th{font-weight:600;background:var(--soft)}
.table-wrap{overflow-x:auto;max-width:100%}
.chips{display:flex;flex-wrap:wrap;gap:8px;padding:0;list-style:none}
.chips a{display:inline-block;padding:5px 12px;border:1px solid var(--border);border-radius:99px;text-decoration:none;background:var(--card);font-size:.92rem}
.chips a[aria-current]{background:var(--accent);color:var(--accent-fg);border-color:var(--accent)}
.site-footer{margin-top:48px;border-top:1px solid var(--border);padding:24px 0 40px;font-size:.92rem;background:var(--card)}
.related ul{display:flex;flex-wrap:wrap;gap:6px 18px;padding:0;list-style:none}
.related h2{font-size:1rem;margin-top:0}
.ad{margin:16px 0;min-height:100px}
/* ---------- form controls ---------- */
label{display:block;font-size:.88rem;font-weight:600;color:var(--muted);margin-bottom:4px}
input,select,textarea,button{font:inherit;color:inherit}
input[type=text],input[type=number],input[type=date],input[type=time],input[type=datetime-local],input[type=url],input[type=email],input[type=tel],input[type=password],input[type=search],select,textarea{width:100%;padding:9px 11px;border:1px solid var(--border);border-radius:calc(var(--radius) / 1.6);background:var(--bg);min-height:42px}
textarea{min-height:180px;resize:vertical;line-height:1.5}
textarea.mono,.mono{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.9rem}
input:focus,select:focus,textarea:focus,button:focus-visible{outline:2px solid var(--accent);outline-offset:1px}
input[type=range]{width:100%;accent-color:var(--accent)}
input[type=checkbox],input[type=radio]{accent-color:var(--accent);width:1.05em;height:1.05em;vertical-align:-2px}
input[type=color]{width:46px;height:38px;padding:2px;border:1px solid var(--border);border-radius:6px;background:var(--bg)}
.check{display:inline-flex;align-items:center;gap:6px;font-weight:500;color:var(--fg);margin:0 14px 6px 0;cursor:pointer}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:9px 16px;border-radius:calc(var(--radius) / 1.6);border:1px solid var(--accent);background:var(--accent);color:var(--accent-fg);font-weight:600;cursor:pointer;text-decoration:none;min-height:42px;line-height:1.2}
.btn:hover{filter:brightness(1.07)}
.btn.ghost{background:transparent;color:var(--accent)}
.btn.small{padding:5px 10px;min-height:32px;font-size:.88rem}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn.big{font-size:1.15rem;padding:14px 28px}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:14px;margin-bottom:14px}
.grid.two{grid-template-columns:repeat(auto-fit,minmax(260px,1fr))}
.row{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:10px 0}
.row.between{justify-content:space-between}
.out{margin-top:16px}
.out:empty{display:none}
.result{background:var(--soft);border-radius:var(--radius);padding:16px;margin-top:14px}
.big-num{font-size:clamp(1.8rem,6vw,2.8rem);font-weight:800;font-family:var(--head);line-height:1.1;color:var(--accent);word-break:break-word}
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px}
.stat{background:var(--soft);border-radius:calc(var(--radius) / 1.4);padding:12px}
.stat b{display:block;font-size:clamp(1.1rem,2.6vw,1.4rem);font-family:var(--head);color:var(--accent);line-height:1.2;word-break:break-word}
.stat span{font-size:.84rem;color:var(--muted)}
.error{color:#c62828;font-weight:600}
.ok{color:#2e7d32;font-weight:600}
/* An inline warning inside a valid answer; .error marks an answer that cannot be used. */
.caution{color:#a3261c;font-weight:600}
.notice{background:var(--soft);padding:10px 14px;border-radius:8px}
.drop{border:2px dashed var(--border);border-radius:var(--radius);padding:28px 16px;text-align:center;cursor:pointer;transition:.15s;background:var(--bg)}
.drop.over,.drop:hover{border-color:var(--accent);background:var(--soft)}
.drop strong{color:var(--accent)}
.files{list-style:none;padding:0;margin:12px 0}
.files li{display:flex;gap:10px;align-items:center;justify-content:space-between;padding:8px 0;border-bottom:1px solid var(--border);flex-wrap:wrap}
.files img{width:48px;height:48px;object-fit:cover;border-radius:6px}
.files .name{flex:1;min-width:120px;word-break:break-all;font-size:.92rem}
.bar{height:8px;border-radius:99px;background:var(--border);overflow:hidden}
.bar i{display:block;height:100%;background:var(--accent);border-radius:99px;transition:width .2s}
.bar.over i{background:#d32f2f}
.preview-box{display:grid;place-items:center;background:repeating-conic-gradient(#8881 0 25%,transparent 0 50%) 0 0/20px 20px;border-radius:var(--radius);border:1px solid var(--border);min-height:120px;padding:10px;overflow:hidden}
.copy-wrap{position:relative}
pre{white-space:pre-wrap;word-break:break-word;background:var(--bg);border:1px solid var(--border);border-radius:8px;padding:12px;margin:8px 0;max-height:520px;overflow:auto}
.note-view{font:15px/1.6 var(--font);max-height:none}
kbd{border:1px solid var(--border);border-bottom-width:2px;border-radius:4px;padding:0 5px;font-size:.85em}
.tabs{display:flex;gap:4px;flex-wrap:wrap;margin-bottom:14px;border-bottom:1px solid var(--border)}
.tabs button{border:0;background:none;padding:8px 14px;cursor:pointer;border-bottom:2px solid transparent;color:var(--muted);font-weight:600}
.tabs button[aria-selected=true]{color:var(--accent);border-color:var(--accent)}
.hl{background:color-mix(in srgb,#ffd54f 70%,transparent);border-radius:2px;color:inherit}
.diff-add{background:color-mix(in srgb,#2e7d32 22%,transparent)}
.diff-del{background:color-mix(in srgb,#c62828 22%,transparent);text-decoration:line-through}
.swatches{display:grid;grid-template-columns:repeat(auto-fit,minmax(110px,1fr));gap:8px}
.swatch{border-radius:var(--radius);min-height:140px;display:flex;flex-direction:column;justify-content:flex-end;padding:10px;cursor:pointer;border:1px solid #0001;font-weight:700}
.center{text-align:center}
.timer{font-size:clamp(2.6rem,12vw,5.5rem);font-weight:800;font-variant-numeric:tabular-nums;text-align:center;font-family:var(--head);line-height:1.1;letter-spacing:-.02em}
.list-out{list-style:none;padding:0}
.list-out li{padding:6px 10px;border-bottom:1px solid var(--border)}
.hidden{display:none!important}
.toast{position:fixed;left:50%;bottom:24px;transform:translateX(-50%);background:var(--fg);color:var(--bg);padding:8px 16px;border-radius:99px;font-size:.9rem;z-index:99;opacity:0;transition:.2s;pointer-events:none}
.toast.show{opacity:1}
.result-peek{position:fixed;left:12px;right:12px;bottom:max(12px,env(safe-area-inset-bottom));z-index:90}
.result-peek[hidden]{display:none}
.result-peek button{display:flex;align-items:center;gap:12px;width:100%;min-height:56px;padding:8px 14px 8px 16px;border:1px solid var(--accent);border-radius:10px;background:var(--card);color:var(--fg);box-shadow:0 10px 28px -10px rgb(0 0 0 / .35);text-align:left;cursor:pointer}
.result-peek-text{flex:1;min-width:0;display:flex;flex-direction:column}
.result-peek-label{font-size:.78rem;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.result-peek-label:empty{display:none}
.result-peek-value{font-size:1.15rem;line-height:1.25;color:var(--accent);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.result-peek-go{display:inline-flex;align-items:center;gap:4px;font-size:.86rem;font-weight:600;color:var(--accent)}
.result-peek-go svg{width:16px;height:16px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
@media print{.result-peek{display:none!important}}
@media (max-width:600px){.card{padding:14px}.site-header nav{gap:12px;font-size:.86rem}.hero{padding-top:18px}}
.print-root{display:none}
@media print{
  body.printing>*:not(.print-root){display:none!important}
  body.printing{background:#fff;color:#000}
  .print-root{display:block!important}
}
/* device tests */
.click-pad,.react-pad{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:6px;width:100%;min-height:260px;margin:12px 0;border:2px dashed var(--border);border-radius:var(--radius);background:var(--bg);color:var(--fg);font:inherit;cursor:pointer;user-select:none;-webkit-user-select:none;touch-action:manipulation}
.click-pad .cp-main,.react-pad .rp-main{font-size:2.4rem;font-weight:800;font-family:var(--head)}
.click-pad:active{background:color-mix(in srgb,var(--accent) 10%,var(--bg))}
.click-pad.done{border-color:var(--accent);border-style:solid}
.react-pad{border-style:solid;color:#fff;background:#2b6cb0}
.react-pad[data-state=wait]{background:#c53030}
.react-pad[data-state=go]{background:#2f855a}
.react-pad[data-state=early]{background:#975a16}
.meter{height:18px;border-radius:99px;background:var(--border);overflow:hidden;margin:12px 0}
.meter-bar{display:block;height:100%;width:0;background:linear-gradient(90deg,#38a169,#d69e2e 75%,#e53e3e);transition:width .05s}
.wave{background:var(--bg);border:1px solid var(--border);border-radius:var(--radius)}
.kb{display:flex;gap:10px;overflow-x:auto;padding:10px;border:1px solid var(--border);border-radius:var(--radius);background:var(--bg);outline-offset:2px}
.kb-block{display:flex;flex-direction:column;gap:5px}.kb-block.main{min-width:540px;flex:15}.kb-block.nav{min-width:100px;flex:3}.kb-block.pad{min-width:132px;flex:4}
.kb-row{display:flex;gap:4px}
.k{flex:1;min-width:0;height:36px;display:grid;place-items:center;border:1px solid var(--border);border-radius:6px;background:var(--card);font-size:.72rem;white-space:nowrap;overflow:hidden}
.k.gap{visibility:hidden}
.k.done{background:color-mix(in srgb,var(--accent) 22%,var(--card));border-color:var(--accent)}
.k.on{background:var(--accent);color:var(--accent-fg)}
.checks{list-style:none;padding:0;margin:10px 0}.checks li{padding:2px 0}
.morse-chart{columns:3 9rem;font-family:ui-monospace,monospace}
.list-out li.focus{background:var(--soft);border-radius:8px;padding-left:8px;padding-right:8px}