:root {
  font-family: "Microsoft YaHei UI", system-ui, sans-serif;
  color: #172033;
  background: #eef3fa;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  background:
    radial-gradient(circle at 12% 18%, #dbe8ff 0, transparent 34%),
    radial-gradient(circle at 88% 82%, #d8f4eb 0, transparent 30%),
    #f5f7fb;
}

.account-shell { width: min(440px, 100%); }

.brand {
  margin-bottom: 20px;
  text-align: center;
}

.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 48px;
  height: 48px;
  margin-bottom: 10px;
  border-radius: 14px;
  color: #fff;
  background: linear-gradient(135deg, #255ed8, #0f9d76);
  font-weight: 800;
  font-size: 20px;
  box-shadow: 0 10px 24px #255ed833;
}

.brand h1 { margin: 0; font-size: 25px; }
.brand p { margin: 7px 0 0; color: #6b768a; font-size: 14px; }

.account-card {
  padding: 30px;
  background: #fff;
  border: 1px solid #dfe6f0;
  border-radius: 18px;
  box-shadow: 0 18px 48px #17203314;
}

.account-card h2 { margin: 0 0 6px; font-size: 23px; }
.intro { margin: 0 0 24px; color: #748096; font-size: 14px; }
.form { display: grid; gap: 17px; }
.field { display: grid; gap: 7px; color: #455168; font-size: 14px; font-weight: 600; }

input, select {
  width: 100%;
  padding: 12px 13px;
  border: 1px solid #cbd5e2;
  border-radius: 10px;
  outline: none;
  color: #172033;
  background: #fbfcfe;
  font: inherit;
  transition: border-color .15s, box-shadow .15s;
}

input:focus, select:focus {
  border-color: #3971df;
  box-shadow: 0 0 0 3px #3971df1f;
}

button {
  margin-top: 3px;
  padding: 12px 16px;
  border: 0;
  border-radius: 10px;
  color: #fff;
  background: #255ed8;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

button:hover { background: #1f52bf; }
button:disabled { cursor: wait; opacity: .6; }

.message {
  display: none;
  margin: 0;
  padding: 11px 13px;
  border-radius: 9px;
  font-size: 14px;
  line-height: 1.5;
}

.message.show { display: block; }
.message.error { color: #a52525; background: #fff0f0; }
.message.success { color: #116846; background: #eaf8f2; }
.switch { margin: 20px 0 0; text-align: center; color: #68748a; font-size: 14px; }
a { color: #255ed8; text-decoration: none; font-weight: 600; }
a:hover { text-decoration: underline; }
.back { margin-top: 18px; text-align: center; font-size: 13px; }

@media (max-width: 480px) {
  body { align-items: start; padding: 28px 16px; }
  .account-card { padding: 24px 20px; }
}