body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  background: linear-gradient(135deg, #f4f7f9 0%, #e8eef5 100%);
  color: #333;
  margin: 0;
  min-height: 100vh;
  padding: 40px 20px;
}

.portal {
  max-width: 960px;
  margin: 0 auto;
}

.portal-header {
  text-align: center;
  margin-bottom: 40px;
}

.portal-header h1 {
  color: #1a253c;
  font-size: 2rem;
  font-weight: 700;
  margin: 0 0 8px;
}

.portal-header p {
  color: #606266;
  margin: 0;
  font-size: 1rem;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.tool-card {
  display: flex;
  flex-direction: column;
  background: #fff;
  border-radius: 12px;
  padding: 24px;
  text-decoration: none;
  color: inherit;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
  transition: transform 0.2s, box-shadow 0.2s;
  border: 1px solid #e8ecf0;
}

.tool-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 30px rgba(64, 158, 255, 0.15);
  border-color: #c6e2ff;
}

.tool-icon {
  font-size: 2rem;
  margin-bottom: 12px;
  line-height: 1;
}

.tool-card h2 {
  font-size: 1.1rem;
  font-weight: 600;
  color: #1a253c;
  margin: 0 0 8px;
}

.tool-card p {
  font-size: 0.9rem;
  color: #909399;
  margin: 0;
  flex-grow: 1;
  line-height: 1.5;
}

.portal-footer {
  text-align: center;
  margin-top: 48px;
  color: #c0c4cc;
  font-size: 0.85rem;
  letter-spacing: 0.02em;
}

@media (max-width: 600px) {
  body { padding: 24px 16px; }
  .portal-header h1 { font-size: 1.5rem; }
  .tool-grid { grid-template-columns: 1fr; }
}