:root{
  --bg:linear-gradient(135deg,#eef1f6, #e8ecf3);
  --card-bg:rgba(255,255,255,.65);
  --text:#1c1c1e;
  --muted:#6e6e73;
  --accent:#0a84ff;
  --ok:#34c759;
  --warn:#ffcc00;
  --alert:#ff3b30;
  --shadow:0 10px 30px rgba(0,0,0,.08);
}
@media (prefers-color-scheme: dark){
  :root{
    --bg:linear-gradient(135deg,#0f1115,#1c1f27);
    --card-bg:rgba(28,31,39,.6);
    --text:#f5f5f7;
    --muted:#a1a1a6;
    --accent:#0a84ff;
    --shadow:0 10px 30px rgba(0,0,0,.4);
  }
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica,Arial,sans-serif;
  color:var(--text);
  background:var(--bg);
}
.container{
  min-height:100vh;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  padding:24px;
  gap:16px;
}
.card{
  width:100%;
  max-width:560px;
  background:var(--card-bg);
  backdrop-filter:saturate(180%) blur(24px);
  border-radius:24px;
  box-shadow:var(--shadow);
  padding:28px;
}
.title{
  margin:0 0 16px;
  font-size:28px;
  font-weight:700;
  letter-spacing:.2px;
}
.segment{
  display:inline-grid;
  grid-template-columns:1fr 1fr;
  gap:0;
  border:1px solid rgba(0,0,0,.1);
  border-radius:12px;
  overflow:hidden;
  margin-right:8px;
  margin-top:8px;
}
.segment input{display:none}
.segment label{
  padding:10px 16px;
  text-align:center;
  cursor:pointer;
  user-select:none;
  color:var(--muted);
  background:transparent;
}
#unitMetric:checked+label{
  color:var(--text);
  background:rgba(255,255,255,.4);
}
#unitImperial:checked+label{
  color:var(--text);
  background:rgba(255,255,255,.4);
}
.fields{
  display:grid;
  grid-template-columns:1fr;
  gap:16px;
  margin:18px 0 0;
}
.field{}.label{
  font-size:14px;
  color:var(--muted);
  margin-bottom:8px;
  display:block;
}
.input-wrap{
  position:relative;
  display:flex;
  align-items:center;
}
.input-wrap input{
  width:100%;
  padding:14px 56px 14px 14px;
  border-radius:12px;
  border:1px solid rgba(0,0,0,.1);
  outline:none;
  background:rgba(255,255,255,.55);
  color:var(--text);
  font-size:16px;
}
.input-wrap input:focus{
  border-color:var(--accent);
  box-shadow:0 0 0 4px rgba(10,132,255,.15);
}
.input-wrap input.error{
  border-color:var(--alert);
  box-shadow:0 0 0 4px rgba(255,59,48,.15);
}
.suffix{
  position:absolute;
  right:12px;
  top:50%;
  transform:translateY(-50%);
  color:var(--muted);
}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.action{
  margin-top:20px;
  width:100%;
  padding:14px 18px;
  border:none;
  border-radius:14px;
  background:var(--accent);
  color:#fff;
  font-size:16px;
  font-weight:600;
  cursor:pointer;
}
.action:active{transform:scale(.997)}
.result{
  margin-top:20px;
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:6px;
}
.value{
  font-size:44px;
  font-weight:800;
  letter-spacing:-.5px;
}
.status{font-size:18px}
.hint{font-size:13px;color:var(--muted)}
.status.ok{color:var(--ok)}
.status.warn{color:var(--warn)}
.status.alert{color:var(--alert)}
.hidden{display:none}
.footer{font-size:12px;color:var(--muted)}
.footer span{color:var(--text)}
@media (max-width:420px){
  .title{font-size:24px}
  .value{font-size:36px}
}