* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.card {
  background: #fff;
  border-radius: 16px;
  padding: 36px 32px;
  width: 100%;
  max-width: 400px;
  box-shadow: 0 20px 60px rgba(0,0,0,.2);
}

.logo {
  display: block;
  max-width: 80px;
  max-height: 80px;
  margin: 0 auto 16px;
  border-radius: 12px;
}

h1 {
  font-size: 22px;
  color: #111827;
  text-align: center;
  margin-bottom: 4px;
}

.subtitle {
  text-align: center;
  color: #6b7280;
  font-size: 13px;
  margin-bottom: 24px;
}

.field { margin-bottom: 16px; }

label {
  display: block;
  font-size: 13px;
  color: #374151;
  margin-bottom: 5px;
  font-weight: 500;
}

input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid #d1d5db;
  border-radius: 8px;
  font-size: 14px;
  outline: none;
  transition: border-color .15s, box-shadow .15s;
}
input:focus {
  border-color: #667eea;
  box-shadow: 0 0 0 3px rgba(102,126,234,.15);
}

.code-row { display: flex; gap: 8px; }
.code-row input { flex: 1; }

button {
  cursor: pointer;
  border: none;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  transition: opacity .15s, transform .1s;
}
button:active { transform: scale(.98); }
button:disabled { opacity: .5; cursor: not-allowed; }

.btn-secondary {
  background: #f3f4f6;
  color: #374151;
  padding: 10px 14px;
  white-space: nowrap;
}
.btn-secondary:hover:not(:disabled) { background: #e5e7eb; }

.btn-primary {
  width: 100%;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  padding: 12px;
  font-size: 15px;
  margin-top: 6px;
}
.btn-primary:hover { opacity: .92; }

.switch {
  text-align: center;
  margin-top: 16px;
  font-size: 13px;
  color: #6b7280;
}
.switch a { color: #667eea; text-decoration: none; }
.switch a:hover { text-decoration: underline; }

.msg {
  margin-top: 14px;
  text-align: center;
  font-size: 14px;
  min-height: 20px;
}
.msg.success { color: #059669; }
.msg.error { color: #dc2626; }
/* （注：内容由AI生成） */