/* NexusMind 官网 — 未来科技感、深色、极简 */

:root {
  --bg-deep: #0a0b0d;
  --bg-card: #12141a;
  --bg-elevated: #181b22;
  --text-primary: #e8eaef;
  --text-secondary: #9ca3b4;
  --text-muted: #6b7280;
  --accent: #22d3ee;
  --accent-dim: #0891b2;
  --accent-glow: rgba(34, 211, 238, 0.25);
  --border: rgba(255, 255, 255, 0.06);
  --radius: 12px;
  --font-sans: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-weight: 400;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-deep);
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  color: var(--text-primary);
}

/* ----- Header ----- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.5rem;
  background: rgba(10, 11, 13, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.logo {
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav a:hover {
  color: var(--accent);
}

.nav .lang-toggle {
  background: none;
  border: none;
  padding: 0;
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  transition: color 0.2s;
}

.nav .lang-toggle:hover {
  color: var(--accent);
}

.menu-toggle {
  display: none;
  width: 28px;
  height: 28px;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
}

.menu-toggle::before,
.menu-toggle::after {
  content: '';
  display: block;
  height: 2px;
  background: var(--text-primary);
  border-radius: 1px;
}

.menu-toggle::before {
  margin-bottom: 6px;
}

.menu-toggle::after {
  width: 70%;
  margin-left: auto;
}

@media (max-width: 768px) {
  .nav {
    display: none;
  }
  .nav.open {
    display: flex;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    padding: 1rem;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
  }
  .menu-toggle {
    display: block;
  }
}

/* ----- Buttons ----- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.25rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: var(--radius);
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.2s;
}

.btn:active {
  transform: scale(0.98);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-dim), var(--accent));
  color: var(--bg-deep);
  border: none;
  box-shadow: 0 0 24px var(--accent-glow);
}

.btn-primary:hover {
  box-shadow: 0 0 32px var(--accent-glow);
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
}

.btn-outline:hover {
  background: rgba(34, 211, 238, 0.1);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border);
}

.btn-ghost:hover {
  color: var(--text-primary);
  border-color: var(--text-muted);
}

/* ----- Hero ----- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 6rem 1.5rem 4rem;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, var(--accent-glow), transparent),
    radial-gradient(ellipse 60% 40% at 80% 60%, rgba(8, 145, 178, 0.12), transparent),
    radial-gradient(ellipse 50% 30% at 20% 80%, rgba(34, 211, 238, 0.08), transparent);
  pointer-events: none;
}

.hero-content {
  position: relative;
  text-align: center;
  max-width: 720px;
}

.hero-tagline {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--accent);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: 1rem;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin: 0 0 1rem;
  background: linear-gradient(180deg, #fff 0%, var(--text-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1.1rem, 2.5vw, 1.35rem);
  color: var(--text-secondary);
  margin: 0 0 0.75rem;
  font-weight: 400;
}

.hero-one-liner {
  font-size: 1rem;
  color: var(--text-muted);
  margin: 0 0 2rem;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}

.hero-cta .btn {
  min-width: 140px;
}

.hero-scroll-hint {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  width: 24px;
  height: 40px;
  border: 2px solid var(--border);
  border-radius: 12px;
  animation: scroll-hint 2s ease-in-out infinite;
}

.hero-scroll-hint::before {
  content: '';
  position: absolute;
  top: 8px;
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  height: 8px;
  background: var(--accent);
  border-radius: 2px;
  opacity: 0.8;
}

@keyframes scroll-hint {
  0%, 100% { opacity: 0.6; transform: translateX(-50%) translateY(0); }
  50% { opacity: 1; transform: translateX(-50%) translateY(6px); }
}

/* ----- Sections ----- */
.section {
  padding: 4rem 1.5rem;
}

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

.section-title {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  text-align: center;
  margin: 0 0 0.5rem;
}

.section-lead {
  text-align: center;
  color: var(--text-muted);
  font-size: 1rem;
  margin: 0 0 2rem;
}

/* ----- Philosophy ----- */
.section-philosophy {
  background: var(--bg-card);
}

.philosophy-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.25rem;
  margin-top: 2rem;
}

.card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.card:hover {
  border-color: rgba(34, 211, 238, 0.3);
  box-shadow: 0 0 20px rgba(34, 211, 238, 0.06);
}

.card-icon {
  font-size: 1.5rem;
  margin-bottom: 0.75rem;
}

.card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
}

.card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin: 0;
  line-height: 1.5;
}

/* ----- Features ----- */
.features-list {
  list-style: none;
  padding: 0;
  margin: 2rem 0 0;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

.feature-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.feature-item:last-child {
  border-bottom: none;
}

.feature-dot {
  flex-shrink: 0;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 10px var(--accent-glow);
}

/* ----- Who ----- */
.section-who {
  background: var(--bg-card);
}

.who-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
  margin-top: 2rem;
}

.who-card {
  padding: 0.85rem 1.25rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color 0.2s, border-color 0.2s;
}

.who-card:hover {
  color: var(--accent);
  border-color: rgba(34, 211, 238, 0.3);
}

/* ----- Plugins ----- */
.plugins-tagline {
  text-align: center;
  font-size: 1.1rem;
  color: var(--accent);
  font-weight: 500;
  margin: 1rem 0 0;
}

/* ----- Pricing ----- */
.pricing-list {
  list-style: none;
  padding: 0;
  margin: 2rem 0;
  max-width: 400px;
  margin-left: auto;
  margin-right: auto;
}

.pricing-list li {
  padding: 0.6rem 0;
  padding-left: 1.5rem;
  position: relative;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.pricing-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

#pricing-cta {
  display: block;
  width: fit-content;
  margin: 0 auto;
}

/* ----- FAQ ----- */
.section-faq {
  background: var(--bg-card);
}

.faq-list {
  max-width: 640px;
  margin: 2rem auto 0;
}

.faq-item {
  border-bottom: 1px solid var(--border);
}

.faq-item summary {
  padding: 1rem 0;
  font-weight: 500;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: '+';
  font-size: 1.25rem;
  color: var(--accent);
  font-weight: 300;
  transition: transform 0.2s;
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
}

.faq-item p {
  padding: 0 0 1.25rem;
  margin: 0;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* ----- Footer ----- */
.site-footer {
  padding: 3rem 1.5rem;
  border-top: 1px solid var(--border);
}

.footer-inner {
  text-align: center;
}

.footer-brand .logo {
  font-size: 1.1rem;
}

.footer-tagline {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 0.25rem 0 1.5rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-links a:hover {
  color: var(--accent);
}

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin: 0;
}