:root{ --bg:#fff; --text:#111827; --muted:#6b7280; --card:#f9fafb; --line:#e5e7eb; }
body{ margin:0; font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial; background:var(--bg); color:var(--text); font-size: 15px;}
.wrap{ max-width:980px; margin:24px auto; padding:0 16px; }
h1{ font-size:20px; margin:0 0 8px; }
.muted{ color:var(--muted); font-size:12px; line-height:1.5; }
.card{ background:var(--card); border:1px solid var(--line); border-radius:14px; padding:14px; margin-top:14px; }
label{ display:block; font-size:16px; color:var(--muted); margin:0 0 6px; }
select,input{ width:100%; padding:10px; border:1px solid var(--line); border-radius:10px; font-size:18px; background:#fff; }
.row{ display:flex; gap:12px; flex-wrap:wrap; align-items:flex-end; }
.col{ flex:1; min-width:260px; }
.mono{ font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace; }
.err{ color:#b00020; font-size:13px; margin-top:10px; display:none; }

.inputWrap{ display:flex; gap:14px; align-items:center; }
.unitLabel{
white-space:nowrap;
font-size:13px;
color:#111827;
padding:6px 10px;
border:1px solid var(--line);
border-radius:999px;
background:#fff;
line-height:1;
}

.topHeader{
background:#000;
color:#fff;
padding:5px 0 5px;
border-bottom:1px solid #111;
}
.topHeader h1{ color:#fff; font-size: 36px;}
.topHeader .muted{ color:#aaaaaa; font-size: 16px;}

/* LaTeX-like fraction */
.u{ display:inline-flex; align-items:flex-end; gap:6px; }
.dot{ padding:0 2px; }
.pow sup{ font-size:0.75em; vertical-align:super; }
.frac{
display:inline-flex;
flex-direction:column;
align-items:center;
line-height:1.05;
transform: translateY(-0.5px);
}
.frac .num{ padding:0 2px; }
.frac .bar{ width:100%; border-top:1px solid #111827; margin:2px 0 1px; }
.frac .den{ padding:0 2px; }

#customBox .row{
display: grid;
grid-template-columns: repeat(4, minmax(120px, 1fr));
gap: 12px;
align-items: flex-end;
}

#customBox .col{
min-width: 0 !important;
}

#customBox input{
width: 100%;
min-width: 0;
box-sizing: border-box;
}

.rowInputs{
align-items: flex-start;
}

#siUnit, #stUnit, #stnUnit {
    border: none !important;
    background: transparent !important;
    padding: 0 !important;
    margin-right: 18px;
    margin-left: 0px;
    border-radius: 0 !important;
    box-shadow: none !important;
    font-size: 0.95em; 
    color: #555;
    }

::placeholder {color: #bbbbbb;opacity: 1;}

.links{
display:flex;
flex-wrap:wrap;
gap:10px;
margin-top:12px;
}

.pill{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:5px 14px;
  border:1px solid rgba(255,255,255,.25);
  border-radius:5px;
  text-decoration:none;
  color:#111827;
  background: linear-gradient(180deg,#f1f3f5 0%,#d9dde2 100%);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.8), 0 4px 14px rgba(0,0,0,.35);
  transition: all .2s ease;
}

.pill:hover{
  border-color: rgba(255,255,255,.6);
  background: linear-gradient(180deg,#ffffff 0%,#e3e7ec 100%);
  transform: translateY(-1px);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.9), 0 6px 20px rgba(0,0,0,.45);
}

.pill:active{
transform: translateY(1px);
}

/* responsive */
@media (max-width: 820px){
#customBox .row{
    grid-template-columns: repeat(2, minmax(140px, 1fr));
}
}

@media (max-width: 420px){
#customBox .row{
    grid-template-columns: 1fr;
}
}

@media (max-width: 820px){
#customBox .row{ grid-template-columns: repeat(2, minmax(140px, 1fr)); }
}
@media (max-width: 420px){
#customBox .row{ grid-template-columns: 1fr; }
}