:root {
  --page-bg: #f5f5f7;
  --surface-bg: rgba(255, 255, 255, 0.86);
  --surface-soft: #fbfbfd;
  --border-color: rgba(60, 60, 67, 0.16);
  --border-strong: rgba(60, 60, 67, 0.24);
  --shadow-soft: 0 18px 48px rgba(15, 23, 42, 0.1), 0 4px 12px rgba(15, 23, 42, 0.05);
}
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: radial-gradient(circle at top, rgba(0, 113, 227, 0.1), transparent 38%), linear-gradient(180deg, var(--page-bg) 0%, #fbfbfd 100%);
  min-height: 100vh;
  display: grid;
  place-items: center;
}
.card {
  width: min(360px, calc(100vw - 32px));
  background: var(--surface-bg);
  border: 1px solid rgba(255, 255, 255, 0.78);
  border-radius: 22px;
  box-shadow: var(--shadow-soft);
  backdrop-filter: saturate(180%) blur(18px);
  padding: 26px 22px;
  box-sizing: border-box;
}
h1 {
  margin: 0 0 6px;
  font-size: 22px;
  color: #111827;
  letter-spacing: -0.03em;
}
label {
  display: block;
  font-size: 13px;
  color: #374151;
  margin: 10px 0 6px;
  font-weight: 600;
}
input {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  font-size: 14px;
  box-sizing: border-box;
  outline: none;
  background: var(--surface-soft);
  transition: border-color .2s ease, box-shadow .2s ease, background .2s ease;
}
input:focus {
  border-color: #0071e3;
  box-shadow: 0 0 0 4px rgba(0, 113, 227, 0.12);
  background: #fff;
}
button {
  width: 100%;
  margin-top: 16px;
  padding: 12px 14px;
  border: none;
  border-radius: 12px;
  background: linear-gradient(180deg, #2997ff 0%, #0071e3 100%);
  color: #fff;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 12px 28px rgba(0, 113, 227, 0.22), 0 2px 8px rgba(0, 113, 227, 0.12);
  transition: transform .18s ease, box-shadow .18s ease, filter .18s ease;
}
button:hover {
  transform: translateY(-1px);
  box-shadow: 0 16px 30px rgba(0, 113, 227, 0.26), 0 3px 10px rgba(0, 113, 227, 0.14);
  filter: saturate(1.05);
}
button:disabled {
  opacity: .7;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}
.msg {
  margin-top: 14px;
  font-size: 13px;
  min-height: 20px;
  color: #dc2626;
}