:root {
  --bg: #f8fafc;
  --primary: #4f46e5;
  --primary-dark: #4338ca;
  --text: #0f172a;
  --muted: #64748b;
  --border: #e2e8f0;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
}

.container {
  width: min(1200px, 92vw);
  margin: 0 auto;
}

.hero {
  background: linear-gradient(145deg, #0f172a, #1d1e43);
  color: #fff;
  padding: 32px 0 80px;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-links {
  display: flex;
  gap: 18px;
  align-items: center;
}

.nav-links a,
.nav-links button {
  color: #e2e8f0;
  text-decoration: none;
  font-size: 14px;
  background: none;
  border: none;
  cursor: pointer;
}

.logo {
  font-weight: 700;
  font-size: 22px;
}

.hero-content {
  margin-top: 60px;
}

.hero h1 {
  font-size: clamp(32px, 6vw, 52px);
  margin-bottom: 16px;
}

.hero p {
  color: rgba(226, 232, 240, 0.9);
  font-size: 18px;
  max-width: 640px;
  line-height: 1.6;
}

.hero-actions {
  margin-top: 24px;
  display: flex;
  gap: 12px;
}

.btn {
  border-radius: 999px;
  padding: 12px 28px;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform 0.2s ease;
  text-decoration: none;
  text-align: center;
}

.btn.primary {
  background: var(--primary);
  color: #fff;
  border-color: transparent;
}

.btn.primary:hover {
  background: var(--primary-dark);
}

.btn.secondary {
  background: #fff;
  color: var(--text);
}

.btn.ghost {
  background: transparent;
  color: #fff;
  border-color: rgba(255, 255, 255, 0.4);
}

.btn.block {
  width: 100%;
}

.btn:hover {
  transform: translateY(-2px);
}

.section {
  padding: 80px 0;
  background: #fff;
}

.section.gray {
  background: #f1f5f9;
}

.section-head {
  text-align: center;
  margin-bottom: 40px;
}

.section-head h2 {
  font-size: 32px;
  margin-bottom: 8px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
}

.grid.apps {
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
}

.card,
.grid > div {
  background: #fff;
  border-radius: 20px;
  padding: 24px;
  border: 1px solid var(--border);
  box-shadow: 0 20px 40px rgba(15, 23, 42, 0.08);
}

.pricing-table {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.card ul {
  padding-left: 18px;
  color: var(--muted);
  line-height: 1.8;
}

.card.featured {
  border: none;
  background: linear-gradient(180deg, #4f46e5, #312e81);
  color: #fff;
}

.card.featured p,
.card.featured li {
  color: #e0e7ff;
}

.testimonials .testimonial-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.testimonials .testimonial {
  background: #fff;
  border-radius: 16px;
  padding: 24px;
  border: 1px solid var(--border);
  display: flex;
  gap: 16px;
  align-items: flex-start;
}

.testimonial img {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  object-fit: cover;
  box-shadow: 0 10px 20px rgba(15, 23, 42, 0.15);
}

.faq-list details {
  margin-bottom: 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  padding: 16px 20px;
  background: #fff;
}

.footer {
  background: #0f172a;
  color: rgba(248, 250, 252, 0.7);
  padding: 40px 0;
}

.footer-links {
  display: flex;
  gap: 16px;
}

.footer-links a {
  color: inherit;
  text-decoration: none;
}

.modal {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal.hidden {
  display: none;
}

.modal-body {
  background: #fff;
  padding: 32px;
  border-radius: 16px;
  width: min(380px, 92vw);
  position: relative;
}

.modal-close {
  position: absolute;
  top: 12px;
  right: 12px;
  border: none;
  background: transparent;
  font-size: 24px;
  cursor: pointer;
}

form label {
  display: block;
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 12px;
}

form input {
  width: 100%;
  margin-top: 6px;
  padding: 12px 14px;
  border-radius: 10px;
  border: 1px solid var(--border);
  font-size: 15px;
}

.auth-tab {
  background: none;
  border: none;
  padding: 8px 16px;
  cursor: pointer;
  color: var(--muted);
  font-size: 15px;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
}

.auth-tab.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
  font-weight: 600;
}

.auth-tab:hover {
  color: var(--text);
}

@media (max-width: 768px) {
  .nav {
    flex-direction: column;
    gap: 12px;
  }

  .hero-actions {
    flex-direction: column;
  }
}