:root{
  --bg:#f7fafc; --bg-elev:#ffffff; --text:#0b0f14; --muted:#4b5563; --brand:#2563eb; --brand-strong:#1d4ed8; --ok:#10b981; --warn:#f59e0b; --err:#ef4444; --card:#ffffff; --stroke:#e5e7eb; --appbar-bg:rgba(255,255,255,0.7); --hint-bg:#f1f5f9;
}
*{box-sizing:border-box}
html,body{height:100%;overflow-x:hidden;}
body{font-family:system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,sans-serif;background:var(--bg);color:var(--text);margin:0}
a{color:var(--brand);text-decoration:none}
.container{max-width:1100px;margin:0 auto;padding:16px;}
.appbar{position:sticky;top:0;backdrop-filter:saturate(180%) blur(8px);background:var(--appbar-bg);border-bottom:1px solid var(--stroke)}
.appbar .inner{display:flex;gap:16px;align-items:center;justify-content:space-between}
.brand{display:flex;gap:10px;align-items:center}
.brand .logo{width:28px;height:28px;border-radius:6px;background:linear-gradient(135deg,var(--brand-strong),#9333ea)}
.brand strong{margin-left:6px}
.appbar nav{display:flex;gap:14px;align-items:center}
.menu-btn,.icon-btn{background:transparent;border:0;color:var(--text);cursor:pointer}
.icon-btn{font-size:1.2rem}
.menu-btn{display:none;font-size:1.5rem}
.btn{background:var(--brand-strong);color:#fff;border:0;border-radius:10px;padding:10px 14px;cursor:pointer;font-weight:600;transition:transform .06s ease,opacity .2s}
.btn:active{transform:translateY(1px)}
.btn.ghost{background:transparent;border:1px solid var(--stroke);color:var(--text)}
.muted{font-size:.9rem;color:var(--muted)}
.grid{display:grid;gap:16px}
@media(min-width:900px){.grid.cols-2{grid-template-columns:1.2fr .8fr}}
.card{background:var(--card);border:1px solid var(--stroke);border-radius:14px;padding:18px;box-shadow:0 10px 30px rgba(0,0,0,.2)}
.drop{border:2px dashed var(--brand-strong);border-radius:14px;padding:28px;text-align:center;background:rgba(59,130,246,.08);transition:border-color .2s,background .2s}
.drop.highlight{border-color:#22d3ee;background:rgba(34,211,238,.08)}
.controls{display:flex;gap:12px;align-items:center;flex-wrap:wrap}
#controls{margin:12px 0 8px}
input[type=number]{border-radius:10px;border:1px solid var(--stroke);background:var(--bg-elev);color:var(--text);padding:10px;width:110px}
#targetNum{width:80px}
#modeToggle{margin-left:8px}
select{border-radius:10px;border:1px solid var(--stroke);background:var(--bg-elev);color:var(--text);padding:6px}
.chips{display:flex;gap:8px}
.chip{border:1px solid var(--stroke);border-radius:999px;padding:6px 10px;cursor:pointer;background:transparent}
footer{border-top:1px solid var(--stroke);margin-top:24px}
footer.container{padding-bottom:24px}
.row{display:flex;gap:12px;align-items:center;flex-wrap:wrap}
.hint{background:var(--hint-bg);border-left:3px solid var(--brand-strong);padding:10px 12px;border-radius:10px}
.toggle{border:1px solid var(--stroke);border-radius:999px;display:inline-flex}
.toggle button{padding:6px 10px;border:0;background:transparent;color:var(--muted);cursor:pointer}
.toggle .active{background:var(--brand-strong);color:#fff;border-radius:999px}
.list{margin-top:10px;text-align:left}
.list .item{display:flex;align-items:center;gap:8px;border-bottom:1px dashed var(--stroke);padding:6px 0}
.list .item .name{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;padding:0 8px;text-shadow:0 1px 2px var(--bg)}
.list .clear{margin-top:8px}
.list .item .item-progress{position:absolute;inset:0;background:var(--bg-elev);border:1px solid var(--stroke);border-radius:8px;overflow:hidden;display:none;pointer-events:none;z-index:-1}
.list .item .item-progress .bar{height:100%;width:0;background:linear-gradient(90deg,var(--ok),#34d399);transition:width .2s ease}
.list .item .cancel-item{background:none;border:0;color:var(--text);cursor:pointer;display:none;margin-left:8px}
.list .item.converting .item-progress{display:block}
.list .item.converting .cancel-item{display:block}
.cancel-item.visible{display:block}
.item-progress.visible{display:block}
.progress{height:12px;background:var(--bg-elev);border:1px solid var(--stroke);border-radius:999px;overflow:hidden}
.progress .bar{height:100%;width:0;background:linear-gradient(90deg,var(--ok),#34d399);transition:width .2s ease}
.warn{color:var(--warn)}
.err{color:var(--err)}
.label-group{display:flex;align-items:center;gap:4px}
.info{position:relative;display:inline-flex;align-items:center}
.info-icon{background:var(--brand-strong);color:#fff;border-radius:50%;width:16px;height:16px;font-size:.75rem;display:inline-flex;align-items:center;justify-content:center;cursor:help}
.tooltip{position:absolute;bottom:125%;left:50%;transform:translateX(-50%);background:var(--appbar-bg);color:var(--text);padding:6px 8px;border-radius:6px;border:1px solid var(--stroke);white-space:normal;width:180px;font-size:.8rem;visibility:hidden;opacity:0;transition:opacity .2s}
.info:hover .tooltip,.info:focus-within .tooltip{visibility:visible;opacity:1}
.steps{list-style:none;padding:0;margin:0;counter-reset:step}
.steps li{counter-increment:step;margin:6px 0 6px 0;padding-left:28px;position:relative}
.steps li::before{content:counter(step);position:absolute;left:0;top:0;background:var(--brand-strong);color:#fff;border-radius:50%;width:20px;height:20px;display:flex;align-items:center;justify-content:center;font-size:.8rem}
/* mobile navigation */
.menu-close{display:none}
@media(max-width:700px){
  .appbar nav{position:fixed;top:0;right:-100%;width:100%;height:100vh;background:var(--bg);flex-direction:column;align-items:flex-start;padding:80px 20px;gap:20px;transition:right .3s;z-index:1000}
  .appbar nav.open{right:0}
  .menu-btn{display:block}
  .menu-close{display:block;position:absolute;top:20px;right:20px;font-size:1.5rem;background:transparent;border:0;color:var(--text);cursor:pointer}
}

main.container{padding-top:18px}
.mt-0{margin-top:0}
.mb-10{margin-bottom:10px}
.mt-12{margin-top:12px}
.mt-16{margin-top:16px}
.ml-8{margin-left:8px}
.row-gap{margin:10px 0}
.label-fixed{min-width:120px;display:inline-block}
.inline-block{display:inline-block}
.text-center{text-align:center}
.hidden{display:none}
#convertRow{margin-top:12px;gap:8px}
#ad-slot{margin-top:12px}
.not-found{display:grid;place-items:center;height:100dvh;text-align:center}