*{box-sizing:border-box}
:root{
  --primary:#4f46e5;
  --primary-hover:#4338ca;
  --primary-soft:#eef2ff;
  --text:#0f172a;
  --text-soft:#475569;
  --text-muted:#94a3b8;
  --border:#e5e7eb;
  --danger:#ef4444;
  --danger-soft:#fef2f2;
  --shadow:0 10px 40px rgba(15,23,42,.10), 0 2px 6px rgba(15,23,42,.05);
  --radius:16px;
  --font:'Inter',-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
}
html,body{height:100%}
body{
  margin:0;
  font-family:var(--font);
  color:var(--text);
  display:flex;align-items:center;justify-content:center;
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(99,102,241,.20), transparent 60%),
    radial-gradient(900px 600px at 110% 110%, rgba(56,189,248,.18), transparent 55%),
    linear-gradient(180deg,#f8fafc 0%, #eef2ff 100%);
  padding:24px;
}
.card{
  width:min(94vw,400px);
  background:rgba(255,255,255,.85);
  backdrop-filter:saturate(140%) blur(8px);
  -webkit-backdrop-filter:saturate(140%) blur(8px);
  border:1px solid rgba(255,255,255,.6);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
  padding:32px 28px 28px;
}
h1{
  margin:0 0 22px;
  font-size:22px;font-weight:600;letter-spacing:.3px;
  text-align:center;color:var(--text);
}
label{
  display:block;margin:14px 0 6px;
  font-size:13px;color:var(--text-soft);font-weight:500;
}
input{
  box-sizing:border-box;width:100%;
  padding:12px 14px;
  border:1px solid var(--border);
  border-radius:10px;
  font-size:15px;
  background:#fff;
  color:var(--text);
  transition:border-color .15s ease, box-shadow .15s ease, background .15s ease;
}
input:hover{border-color:#cbd5e1}
input:focus{
  outline:0;
  border-color:var(--primary);
  box-shadow:0 0 0 3px rgba(79,70,229,.15);
  background:#fff;
}
button[type=submit]{
  width:100%;margin-top:22px;
  padding:12px 14px;border:0;border-radius:10px;
  background:linear-gradient(135deg,#6366f1 0%, #4f46e5 100%);
  color:#fff;font-size:15px;font-weight:600;letter-spacing:.5px;cursor:pointer;
  box-shadow:0 6px 16px rgba(79,70,229,.30);
  transition:transform .12s ease, box-shadow .15s ease, filter .15s ease;
}
button[type=submit]:hover{
  filter:brightness(1.05);
  box-shadow:0 10px 22px rgba(79,70,229,.35);
  transform:translateY(-1px);
}
button[type=submit]:active{transform:translateY(0);box-shadow:0 4px 10px rgba(79,70,229,.25);}
.err{
  margin:14px 0 0;
  padding:10px 12px;
  background:var(--danger-soft);
  color:#b91c1c;
  border:1px solid #fecaca;
  border-radius:10px;
  font-size:13px;
  text-align:center;
}
.hint{
  color:var(--text-muted);
  font-size:12.5px;line-height:1.7;
  margin-top:18px;text-align:center;
}