:root {
  --brand: #1f6feb;
  --tx: #1f2937;
  --tx2: #6b7280;
  --bd: #e5e7eb;
  --bg: #f3f4f6;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(160deg, #eef2ff, #f3f4f6 60%);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--tx);
}
.login-wrap { width: 100%; max-width: 380px; padding: 16px; }
.login-card {
  background: #fff;
  border: 1px solid var(--bd);
  border-radius: 16px;
  padding: 32px 28px;
  box-shadow: 0 12px 40px rgba(0,0,0,.08);
}
.login-logo {
  width: 56px; height: 56px; border-radius: 14px;
  background: var(--brand); color: #fff; font-weight: 700; font-size: 22px;
  display: flex; align-items: center; justify-content: center; margin: 0 auto 14px;
}
.login-card h1 { text-align: center; font-size: 20px; margin: 0 0 4px; }
.login-sub { text-align: center; color: var(--tx2); margin: 0 0 22px; font-size: 13px; }
.field { display: block; margin-bottom: 14px; }
.field > span { display: block; font-size: 13px; color: var(--tx2); margin-bottom: 6px; }
.input, .login-card input {
  width: 100%; padding: 11px 12px; border: 1px solid var(--bd); border-radius: 9px;
  font-size: 14px; outline: none; transition: border-color .15s;
}
.login-card input:focus { border-color: var(--brand); }
.btn {
  cursor: pointer; border: 1px solid var(--bd); background: #fff; color: var(--tx);
  padding: 9px 14px; border-radius: 9px; font-size: 14px; transition: all .15s;
}
.btn.primary { background: var(--brand); border-color: var(--brand); color: #fff; }
.btn.primary:hover { filter: brightness(1.05); }
.btn.block { width: 100%; padding: 12px; font-size: 15px; font-weight: 600; margin-top: 4px; }
.btn:disabled { opacity: .6; cursor: not-allowed; }
.login-err { color: #dc2626; font-size: 13px; min-height: 18px; margin: 2px 0 8px; text-align: center; }
.login-tip { text-align: center; color: var(--tx2); font-size: 12px; margin: 14px 0 0; }