/* ============================================
   光启LightAI 官网 — 自定义样式
   Design Direction: Luxury Tech / Editorial
   ============================================ */

/* ---- CSS Variables ---- */
:root {
  /* OKLCH Color System */
  --brand-blue: oklch(55% 0.18 250);
  --brand-blue-light: oklch(85% 0.08 250);
  --brand-blue-dark: oklch(30% 0.12 250);
  --brand-gold: oklch(75% 0.15 85);
  --brand-gold-light: oklch(90% 0.06 85);
  --brand-gold-dark: oklch(55% 0.12 85);

  /* Tinted Neutrals (cool-blue tint) */
  --surface-dark: oklch(14% 0.01 250);
  --surface-dark-mid: oklch(18% 0.01 250);
  --surface-dark-light: oklch(22% 0.01 250);
  --surface-light: oklch(96% 0.008 250);
  --surface-light-mid: oklch(93% 0.008 250);
  --surface-white: oklch(98% 0.005 250);

  --text-primary: oklch(12% 0.02 250);
  --text-secondary: oklch(40% 0.02 250);
  --text-muted: oklch(60% 0.01 250);
  --text-on-dark: oklch(95% 0.01 250);
  --text-on-dark-muted: oklch(70% 0.01 250);

  /* Shadows */
  --shadow-sm: 0 1px 3px oklch(0% 0 0 / 0.08);
  --shadow-md: 0 4px 12px oklch(0% 0 0 / 0.12);
  --shadow-lg: 0 12px 40px oklch(0% 0 0 / 0.16);

  /* Spacing rhythm (base unit 24px) */
  --rhythm: 1.5rem;
  --rhythm-2: 3rem;
  --rhythm-3: 4.5rem;
  --rhythm-4: 6rem;
  --rhythm-5: 7.5rem;

  /* Typography */
  --font-display: 'Plus Jakarta Sans', 'Noto Sans SC', system-ui, sans-serif;
  --font-body: 'Noto Sans SC', 'Plus Jakarta Sans', system-ui, sans-serif;

  /* Transitions */
  --ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1);
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
}

/* ---- Base Styles ---- */
html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  color: var(--text-primary);
  background: var(--surface-white);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: oklch(55% 0.18 250 / 0.3);
}

/* ---- Hero Section ---- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: var(--surface-dark);
}

.hero-canvas {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: var(--rhythm-4);
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 6vw + 1rem, 5rem);
  font-weight: 800;
  color: var(--text-on-dark);
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: var(--rhythm);
}

.hero-title .brand-gold {
  color: var(--brand-gold);
}

.hero-slogan {
  font-family: var(--font-display);
  font-size: clamp(1.1rem, 2vw + 0.5rem, 1.6rem);
  font-weight: 300;
  color: var(--brand-gold-light);
  letter-spacing: 0.08em;
  margin-bottom: var(--rhythm-2);
}

.hero-desc {
  font-size: clamp(0.9rem, 1.5vw + 0.3rem, 1.15rem);
  color: var(--text-on-dark-muted);
  max-width: 65ch;
  margin: 0 auto var(--rhythm-2);
  line-height: 1.8;
}

.hero-cta-group {
  display: flex;
  gap: var(--rhythm);
  justify-content: center;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  background: var(--brand-gold);
  color: var(--surface-dark);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.9375rem;
  border-radius: 0.5rem;
  border: none;
  cursor: pointer;
  transition: all 0.3s var(--ease-out-quart);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.btn-primary:hover {
  background: var(--brand-gold-light);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px oklch(75% 0.15 85 / 0.4);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  background: transparent;
  color: var(--text-on-dark);
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 0.9375rem;
  border-radius: 0.5rem;
  border: 1px solid oklch(70% 0.01 250);
  cursor: pointer;
  transition: all 0.3s var(--ease-out-quart);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.btn-secondary:hover {
  border-color: var(--brand-gold);
  color: var(--brand-gold-light);
  transform: translateY(-2px);
}

.hero-gradient-fade {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 120px;
  background: linear-gradient(to bottom, transparent, var(--surface-light));
  z-index: 2;
}

/* ---- Section Base ---- */
.section {
  padding: clamp(3rem, 5vw + 2rem, 6rem) clamp(1.5rem, 3vw, 4rem);
}

.section-dark {
  background: var(--surface-dark);
  color: var(--text-on-dark);
}

.section-light {
  background: var(--surface-light);
  color: var(--text-primary);
}

.section-white {
  background: var(--surface-white);
  color: var(--text-primary);
}

.section-header {
  text-align: center;
  margin-bottom: var(--rhythm-3);
}

.section-header h2 {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3vw + 0.5rem, 2.8rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.section-header p {
  font-size: clamp(0.9rem, 1.2vw + 0.3rem, 1.05rem);
  color: var(--text-muted);
  max-width: 55ch;
  margin: var(--rhythm) auto 0;
  line-height: 1.7;
}

.section-dark .section-header p {
  color: var(--text-on-dark-muted);
}

.section-header .accent-line {
  width: 60px;
  height: 3px;
  background: var(--brand-gold);
  margin: var(--rhythm) auto 0;
  border-radius: 2px;
}

/* ---- Pain Points Section ---- */
.pain-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--rhythm-2);
  max-width: 1100px;
  margin: 0 auto;
}

.pain-card {
  padding: var(--rhythm-2) var(--rhythm);
  border-radius: 1rem;
  border: 1px solid oklch(88% 0.01 250);
  background: var(--surface-white);
  transition: all 0.4s var(--ease-out-quart);
  position: relative;
  overflow: hidden;
}

.pain-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: oklch(60% 0.02 250 / 0.3);
  transition: background 0.4s var(--ease-out-quart);
}

.pain-card:hover {
  transform: translateY(-4px);
  border-color: var(--brand-blue-light);
  box-shadow: var(--shadow-lg);
}

.pain-card:hover::before {
  background: var(--brand-blue);
}

.pain-icon {
  width: 48px;
  height: 48px;
  margin-bottom: var(--rhythm);
  color: var(--brand-blue);
}

.pain-card h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--rhythm);
  letter-spacing: -0.01em;
}

.pain-card p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.pain-card .pain-quote {
  margin-top: var(--rhythm);
  padding-top: var(--rhythm);
  border-top: 1px solid oklch(88% 0.01 250);
  font-size: 0.875rem;
  color: var(--text-muted);
  font-style: italic;
}

/* ---- Solution Chain ---- */
.solution-chain {
  display: flex;
  flex-direction: column;
  gap: 0;
  max-width: 900px;
  margin: 0 auto;
  position: relative;
}

.solution-step {
  display: flex;
  align-items: flex-start;
  gap: var(--rhythm-2);
  padding: var(--rhythm-2) 0;
  position: relative;
}

.solution-step:not(:last-child)::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 36px;
  width: 2px;
  height: calc(100% - var(--rhythm-2) - 48px);
  background: linear-gradient(to bottom, var(--brand-blue), var(--brand-gold));
  transform: translateX(-1px);
}

.step-number {
  width: 72px;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 800;
  border-radius: 1rem;
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.step-number.step-1 {
  background: oklch(90% 0.04 250);
  color: var(--brand-blue-dark);
}

.step-number.step-2 {
  background: oklch(88% 0.06 250);
  color: var(--brand-blue-dark);
}

.step-number.step-3 {
  background: oklch(86% 0.08 250);
  color: var(--brand-blue-dark);
}

.step-number.step-4 {
  background: var(--brand-gold-light);
  color: var(--brand-gold-dark);
}

.step-content h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.step-content p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.step-content .step-tags {
  display: flex;
  gap: 0.5rem;
  margin-top: var(--rhythm);
  flex-wrap: wrap;
}

.step-tag {
  padding: 0.25rem 0.75rem;
  font-size: 0.8125rem;
  background: oklch(90% 0.02 250);
  color: var(--text-secondary);
  border-radius: 0.375rem;
  font-weight: 500;
}

/* ---- Features Grid ---- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--rhythm);
  max-width: 1100px;
  margin: 0 auto;
}

.feature-card {
  padding: var(--rhythm-2) var(--rhythm);
  border-radius: 0.875rem;
  background: var(--surface-white);
  border: 1px solid oklch(90% 0.01 250);
  transition: all 0.4s var(--ease-out-quart);
  position: relative;
  cursor: default;
}

.feature-card:hover {
  border-color: var(--brand-blue-light);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.feature-card:hover .feature-expand {
  opacity: 1;
  max-height: 200px;
  margin-top: var(--rhythm);
}

.feature-icon {
  width: 40px;
  height: 40px;
  margin-bottom: var(--rhythm);
  color: var(--brand-blue);
}

.feature-card h3 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.feature-card .feature-brief {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.feature-expand {
  opacity: 0;
  max-height: 0;
  overflow: hidden;
  transition: all 0.4s var(--ease-out-expo);
  font-size: 0.8125rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.feature-expand ul {
  list-style: none;
  padding: 0;
}

.feature-expand li {
  padding: 0.25rem 0;
  padding-left: 1rem;
  position: relative;
}

.feature-expand li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.625rem;
  width: 5px;
  height: 5px;
  background: var(--brand-blue);
  border-radius: 50%;
}

@media (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .features-grid {
    grid-template-columns: 1fr;
  }
}


/* ---- Advantages Grid ---- */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--rhythm);
  max-width: 1100px;
  margin: 0 auto;
}

.advantage-card {
  padding: var(--rhythm) var(--rhythm-2);
  border-radius: 0.75rem;
  background: var(--surface-white);
  border: 1px solid oklch(90% 0.01 250);
  transition: all 0.3s var(--ease-out-quart);
  display: flex;
  align-items: flex-start;
  gap: var(--rhythm);
}

.advantage-card:hover {
  border-color: var(--brand-blue-light);
  transform: translateY(-2px);
}

.advantage-icon {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
  color: var(--brand-gold);
}

.advantage-card h3 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.375rem;
}

.advantage-card p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ---- Target Customers ---- */
.customers-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--rhythm);
}

.customer-item {
  display: flex;
  align-items: flex-start;
  gap: var(--rhythm);
  padding: var(--rhythm) var(--rhythm-2);
  border-radius: 0.75rem;
  background: var(--surface-white);
  border: 1px solid oklch(90% 0.01 250);
  transition: all 0.3s var(--ease-out-quart);
}

.customer-item:hover {
  border-color: var(--brand-gold-light);
  background: oklch(96% 0.008 85);
}

.customer-icon {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
  color: var(--brand-blue);
}

.customer-item h3 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.customer-item p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ---- CTA / Contact Section ---- */
.cta-section {
  text-align: center;
}

.cta-heading {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3vw + 0.5rem, 2.5rem);
  font-weight: 800;
  color: var(--brand-gold);
  margin-bottom: var(--rhythm);
  letter-spacing: -0.02em;
}

.cta-desc {
  font-size: 1rem;
  color: var(--text-on-dark-muted);
  max-width: 55ch;
  margin: 0 auto var(--rhythm-2);
  line-height: 1.7;
}

.contact-info {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--rhythm);
  max-width: 800px;
  margin: 0 auto var(--rhythm-2);
  text-align: left;
}

.contact-item {
  padding: var(--rhythm);
  border-radius: 0.75rem;
  background: oklch(20% 0.012 250);
  border: 1px solid oklch(28% 0.01 250);
}

.contact-item .contact-label {
  font-size: 0.8125rem;
  color: oklch(60% 0.01 250);
  margin-bottom: 0.375rem;
  font-weight: 500;
}

.contact-item .contact-value {
  font-size: 0.9375rem;
  color: var(--text-on-dark);
  font-weight: 600;
}

/* ---- Footer ---- */
.site-footer {
  padding: var(--rhythm-2) var(--rhythm-4);
  background: oklch(10% 0.01 250);
  text-align: center;
}

.footer-text {
  font-size: 0.8125rem;
  color: oklch(50% 0.01 250);
}

/* ---- Scroll Animations ---- */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s var(--ease-out-expo), transform 0.6s var(--ease-out-expo);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }


/* ---- Navigation ---- */
.nav-bar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 0.75rem clamp(1.5rem, 3vw, 3rem);
  background: oklch(14% 0.01 250 / 0.85);
  backdrop-filter: blur(12px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: all 0.3s var(--ease-out-quart);
  border-bottom: 1px solid oklch(25% 0.01 250 / 0);
}

.nav-bar.scrolled {
  border-bottom-color: oklch(25% 0.01 250 / 0.5);
}

.nav-logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-on-dark);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.nav-logo .gold {
  color: var(--brand-gold);
}

.nav-links {
  display: flex;
  gap: var(--rhythm);
  align-items: center;
}

.nav-links a {
  font-size: 0.875rem;
  color: var(--text-on-dark-muted);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--brand-gold-light);
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
}

/* ---- Decorative Elements ---- */
.glow-orb {
  position: absolute;
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: radial-gradient(circle, oklch(75% 0.15 85 / 0.08), transparent 70%);
  pointer-events: none;
  z-index: 0;
}

.glow-orb-blue {
  background: radial-gradient(circle, oklch(55% 0.18 250 / 0.08), transparent 70%);
}

/* ---- Responsive ---- */
@media (max-width: 768px) {
  .solution-step {
    flex-direction: column;
    gap: var(--rhythm);
  }

  .solution-step:not(:last-child)::after {
    left: 36px;
    top: 72px;
    height: calc(100% - 72px - var(--rhythm-2));
  }

  .step-number {
    width: 56px;
    height: 56px;
    font-size: 1.25rem;
  }

  .pain-grid {
    grid-template-columns: 1fr;
  }
}