body {
  font-family: "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  background: #f5f6fa;
  color: #222;
  margin: 0;
  padding: 0;
}
.container {
  max-width: 700px;
  margin: 0 auto;
  padding: 0 16px;
}
.card-title {
  font-size: 1.3em;
  font-weight: 600;
  color: #222;
  margin-bottom: 18px;
  letter-spacing: 0.5px;
}
.btn, button {
  border: none;
  border-radius: 8px;
  padding: 10px 20px;
  font-size: 16px;
  background: #3370ff;
  color: #fff;
  cursor: pointer;
  transition: background 0.2s;
  outline: none;
}
.btn-link {
  background: none;
  color: #3370ff;
  padding: 0;
  font-size: 16px;
  box-shadow: none;
}
.btn:active, .btn:hover, .btn-primary:hover {
  background: #2255cc;
  color: #fff;
}
.btn-primary {
  background: #3370ff;
  color: #fff;
}
@media (max-width: 700px) {
  .container {
    max-width: 100vw;
    padding: 0 6px;
  }
  .btn, button {
    font-size: 15px;
    padding: 8px 12px;
  }
}