[hidden]{display:none!important}
:root{--ink:#15171a;--steel:#e9ecef;--mat:#4d5560;--grid:rgba(255,255,255,.14);--tape:#ffc933;--jaw:#e0402a;--paper:#fff;--mute:#5d646d;--line:#c9ced4}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--steel);color:var(--ink);font:17px/1.6 Archivo,system-ui,sans-serif}
a{color:var(--ink);text-decoration-color:var(--jaw);text-underline-offset:3px}
.top{display:flex;align-items:center;gap:12px;background:var(--ink);color:#fff;padding:8px 16px;position:relative;z-index:5}
.brand{display:flex;align-items:center;gap:8px;color:#fff;text-decoration:none;font-weight:800;letter-spacing:.2px;white-space:nowrap}
.brand svg{width:26px;height:26px}
.menu-btn{margin-left:auto;background:none;border:1px solid #fff6;color:#fff;border-radius:4px;padding:5px 10px;font:inherit;font-size:15px}
.menu{display:none;position:absolute;left:0;right:0;top:100%;background:var(--ink);padding:8px 16px 14px;flex-direction:column}
.menu.open{display:flex}.menu a{color:#fff;text-decoration:none;padding:7px 0;border-bottom:1px solid #fff2}.menu a[aria-current]{color:var(--tape)}
@media(min-width:980px){.menu-btn{display:none}.menu{display:flex;position:static;flex-direction:row;padding:0;margin-left:auto;gap:16px;background:none}.menu a{border:0;font-size:15px}}
/* tool */
.tool{position:relative;background:var(--mat);color:#fff;user-select:none;-webkit-user-select:none;touch-action:none;overflow:hidden}
.tool canvas{display:block;width:100%;height:100%}
.tool{height:min(78vh,640px);min-height:440px}
.hud{position:absolute;left:12px;right:12px;bottom:12px;flex-direction:column-reverse;display:flex;flex-wrap:wrap;gap:8px;align-items:flex-start;pointer-events:none}
.tool.vert .hud{left:60px}
.read{pointer-events:auto;background:var(--ink);border-left:6px solid var(--jaw);padding:6px 12px 8px;border-radius:4px;min-width:200px}
.read b{display:block;font:700 clamp(30px,6vw,46px)/1.1 'JetBrains Mono',ui-monospace,monospace}
.read span{font:13px 'JetBrains Mono',ui-monospace,monospace;color:#cfd4da}
.ctl{pointer-events:auto;display:flex;flex-wrap:wrap;gap:6px}
.chip{font:600 15px Archivo,sans-serif;background:#fff;color:var(--ink);border:2px solid var(--ink);border-radius:4px;padding:6px 11px;min-height:40px;cursor:pointer}
.chip[aria-pressed=true]{background:var(--tape)}
.chip.go{background:var(--tape)}
.calib{position:absolute;inset:0;display:none;z-index:3}
.tool.calibrating .calib{display:block}
.calib .card{position:absolute;left:24px;top:76px;border:3px dashed var(--tape);border-radius:4%/6.3%;background:rgba(255,201,51,.08);color:var(--tape)}
.calib .card p{margin:12px 14px;font-weight:700;font-size:15px;line-height:1.35}
.calib .handle{position:absolute;right:-22px;bottom:-22px;width:44px;height:44px;border-radius:50%;background:var(--tape);border:3px solid var(--ink);cursor:nwse-resize;touch-action:none}
.calib .bar{position:absolute;left:12px;right:12px;bottom:12px;display:flex;flex-wrap:wrap;gap:8px;align-items:center;background:var(--ink);padding:10px;border-radius:6px}
.calib .bar label{font-size:14px}.calib select,.calib input{font:15px Archivo;padding:6px;border-radius:4px;border:0;max-width:150px}
.calib .coin{position:absolute;border:3px dashed var(--tape);border-radius:50%;display:none}
.calib.coinmode .card{display:none}.calib.coinmode .coin{display:block}
.hint{position:absolute;right:12px;top:58px;max-width:60%;text-align:right;font-size:13px;color:#dfe3e7;background:#15171acc;padding:4px 8px;border-radius:4px;pointer-events:none}
.tool.calibrating .hint{display:none}.tool.vert .hint{top:12px}.tool.calibrating .hud{visibility:hidden}
.toast{position:fixed;left:50%;bottom:20px;transform:translateX(-50%);background:var(--ink);color:#fff;padding:8px 14px;border-radius:4px;opacity:0;transition:opacity .2s;z-index:9}.toast.on{opacity:1}
/* reading */
.sheet{max-width:1080px;margin:0 auto;padding:28px 16px 48px}
.lead{display:grid;gap:8px;margin-bottom:18px}
h1{font:800 clamp(28px,4.4vw,42px)/1.12 Archivo,sans-serif;margin:0}
.lead p{margin:0;color:var(--mute);font-size:18px}
.spec{display:grid;gap:22px}
@media(min-width:900px){.spec{grid-template-columns:240px 1fr}}
.spec nav{font-size:15px}.spec nav ol{margin:0;padding-left:18px}
@media(min-width:900px){.spec nav{position:sticky;top:12px;align-self:start}}
.spec article{background:var(--paper);border:2px solid var(--ink);border-radius:4px;padding:6px 22px 22px;box-shadow:6px 6px 0 var(--tape)}
h2{font:800 24px/1.25 Archivo,sans-serif;margin:26px 0 8px;padding-top:8px;border-top:3px solid var(--ink)}
h2:first-child{border-top:0;margin-top:10px}
h3{font-size:18px;margin:18px 0 4px}
.tablebox{overflow-x:auto}table{border-collapse:collapse;width:100%;font-size:15px}th,td{border:1px solid var(--line);padding:6px 8px;text-align:left}th{background:var(--steel)}
.mono{font-family:'JetBrains Mono',ui-monospace,monospace}
.faq details{border-top:1px solid var(--line);padding:10px 0}.faq summary{font-weight:700;cursor:pointer}
.note{font-size:14px;color:var(--mute)}
.cta{display:inline-block;background:var(--tape);border:2px solid var(--ink);padding:8px 14px;border-radius:4px;font-weight:700;text-decoration:none}
footer{background:var(--ink);color:#cfd4da;font-size:14px;padding:22px 16px}footer a{color:#fff;margin-right:14px}
footer div{max-width:1080px;margin:0 auto}
.size-box{margin:10px 0;border:3px solid var(--jaw)}
.calc{display:flex;flex-wrap:wrap;gap:10px;align-items:end}.calc label{display:block;font-size:14px}.calc input,.calc select{font:16px Archivo;padding:7px;border:2px solid var(--ink);border-radius:4px;width:120px}
.tool.vert .calib .card{left:60px;top:20px}.tool.vert .calib .coin{left:70px!important}