/* ===== 变量 ===== */
:root {
  --color-bg: #ffffff;
  --color-bg-alt: #f8fafc;
  --color-text: #0f172a;
  --color-text-secondary: #475569;
  --color-text-muted: #94a3b8;
  --color-border: #e2e8f0;
  --color-border-light: #f1f5f9;
  --color-accent: #0ea5e9;
  --color-accent-light: #e0f2fe;
  --font-display: 'Noto Serif SC', 'PingFang SC', 'Hiragino Sans GB', serif;
  --font-body: 'Noto Sans SC', 'PingFang SC', 'Hiragino Sans GB', sans-serif;
  --nav-height: 72px;
  --transition: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.04);
  --shadow-md: 0 4px 12px -2px rgb(0 0 0 / 0.06), 0 2px 6px -1px rgb(0 0 0 / 0.04);
  --shadow-lg: 0 12px 32px -4px rgb(0 0 0 / 0.08), 0 4px 8px -2px rgb(0 0 0 / 0.04);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  text-decoration: none;
  color: inherit;
}

ul {
  list-style: none;
}

img {
  max-width: 100%;
}

.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== 导航栏 ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 1000;
  transition: background var(--transition), box-shadow var(--transition);
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 1px 0 var(--color-border);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--color-text);
  transition: var(--transition);
}

.logo:hover {
  opacity: 0.7;
}

.logo-icon {
  width: 32px;
  height: 32px;
  color: var(--color-accent);
}

.logo-text {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.nav-links {
  display: flex;
  gap: 36px;
}

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

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-text);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  border-radius: 1px;
  transition: width var(--transition);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.mobile-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

.mobile-toggle span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--color-text);
  transition: var(--transition);
  margin: 0 auto;
}

.mobile-toggle.active span:nth-child(1) {
  transform: translateY(3.75px) rotate(45deg);
}

.mobile-toggle.active span:nth-child(2) {
  transform: translateY(-3.75px) rotate(-45deg);
}

/* ===== Hero ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--nav-height);
  background: var(--color-bg);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -20%;
  right: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--color-accent-light) 0%, transparent 70%);
  opacity: 0.6;
  pointer-events: none;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 60px;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-content {
  padding: 40px 0;
}

.hero-label {
  font-size: 0.85rem;
  color: var(--color-accent);
  font-weight: 600;
  letter-spacing: 2px;
  margin-bottom: 24px;
  display: inline-block;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text);
  margin-bottom: 28px;
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--color-text-secondary);
  line-height: 1.8;
  max-width: 480px;
  margin-bottom: 40px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 32px;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  border-radius: 10px;
  transition: var(--transition);
  cursor: pointer;
  border: none;
  font-family: inherit;
}

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

.btn--primary:hover {
  background: var(--color-accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn--outline {
  background: transparent;
  color: var(--color-text);
  border: 1.5px solid var(--color-border);
}

.btn--outline:hover {
  border-color: var(--color-text);
  background: var(--color-bg-alt);
  transform: translateY(-2px);
}

/* Hero 视觉装饰 */
.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.shape-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  width: 280px;
  height: 280px;
}

.shape {
  border-radius: 20px;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.shape-1 {
  background: linear-gradient(135deg, #e0f2fe 0%, #bae6fd 100%);
}

.shape-2 {
  background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
  transform: translateY(20px);
}

.shape-3 {
  background: linear-gradient(135deg, #f8fafc 0%, #f0f9ff 100%);
  transform: translateY(-20px);
}

.shape-4 {
  background: linear-gradient(135deg, #bae6fd 0%, #7dd3fc 100%);
}

/* ===== 通用区块 ===== */
section {
  padding: 120px 0;
  position: relative;
}

.section-label {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 3px;
  color: var(--color-accent);
  text-transform: uppercase;
  margin-bottom: 16px;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-text);
  margin-bottom: 20px;
}

.section-subtitle {
  color: var(--color-text-secondary);
  font-size: 1.05rem;
  max-width: 480px;
  margin: 0 auto;
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

/* ===== 关于 ===== */
.about {
  background: var(--color-bg-alt);
}

.about-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
}

.about-text p {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  line-height: 1.9;
  margin-bottom: 16px;
}

.about-text p:last-child {
  margin-bottom: 0;
}

.stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.stat-item {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  padding: 32px 28px;
  transition: var(--transition);
}

.stat-item:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
  border-color: var(--color-border-light);
}

.stat-num {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1;
  display: block;
  margin-bottom: 8px;
}

.stat-label {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  font-weight: 500;
}

/* ===== 服务 ===== */
.services {
  background: var(--color-bg);
}

.service-cards {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-bottom: 64px;
}

.service-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  padding: 36px 28px;
  transition: var(--transition);
}

.service-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-6px);
  border-color: var(--color-border-light);
}

.service-icon {
  width: 48px;
  height: 48px;
  background: var(--color-accent-light);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent);
  margin-bottom: 24px;
}

.service-icon svg {
  width: 24px;
  height: 24px;
}

.service-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 12px;
}

.service-card p {
  font-size: 0.88rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.tech-stack {
  text-align: center;
  padding-top: 32px;
  border-top: 1px solid var(--color-border);
}

.tech-label {
  display: block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 3px;
  color: var(--color-text-muted);
  text-transform: uppercase;
  margin-bottom: 20px;
}

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}

.tech-tags span {
  padding: 8px 18px;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  transition: var(--transition);
}

.tech-tags span:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-light);
}

/* ===== 案例 ===== */
.portfolio {
  background: var(--color-bg-alt);
}

.portfolio-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.portfolio-card {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 32px;
  align-items: center;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 20px;
  padding: 36px 40px;
  transition: var(--transition);
}

.portfolio-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-border-light);
}

.portfolio-visual {
  width: 72px;
  height: 72px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.portfolio-visual svg {
  width: 32px;
  height: 32px;
}

.visual-blue {
  background: #e0f2fe;
  color: #0284c7;
}

.visual-green {
  background: #dcfce7;
  color: #16a34a;
}

.visual-amber {
  background: #fef3c7;
  color: #d97706;
}

.portfolio-info h4 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
}

.portfolio-info p {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: 14px;
}

.portfolio-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.portfolio-tags span {
  padding: 4px 12px;
  background: var(--color-bg-alt);
  border-radius: 6px;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

/* ===== 联系 ===== */
.contact {
  background: var(--color-bg);
}

.contact-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
}

.contact-text p {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  line-height: 1.9;
  max-width: 420px;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.contact-item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 24px 28px;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 14px;
  transition: var(--transition);
}

.contact-item:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-sm);
}

.contact-item-label {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 1px;
  color: var(--color-text-muted);
  text-transform: uppercase;
}

.contact-item-value {
  font-size: 1rem;
  color: var(--color-text);
  font-weight: 500;
}

/* ===== 页脚 ===== */
.footer {
  padding: 32px 0;
  background: var(--color-bg);
  border-top: 1px solid var(--color-border);
}

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

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--color-text-secondary);
  font-weight: 600;
  font-size: 0.95rem;
}

.footer-logo {
  width: 28px;
  height: 28px;
  color: var(--color-text-muted);
}

.footer-copy {
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

/* ===== 滚动动画 ===== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s cubic-bezier(0.4, 0, 0.2, 1), transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

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

/* ===== 响应式 ===== */
@media (max-width: 968px) {
  .hero-inner,
  .about-inner,
  .contact-inner {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .hero-visual {
    order: -1;
    justify-content: flex-start;
  }

  .shape-grid {
    width: 220px;
    height: 220px;
  }

  .service-cards {
    grid-template-columns: repeat(2, 1fr);
  }

  section {
    padding: 80px 0;
  }
}

@media (max-width: 768px) {
  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 40px 24px;
    gap: 0;
    transform: translateX(100%);
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
  }

  .nav-links.active {
    transform: translateX(0);
    opacity: 1;
    pointer-events: all;
  }

  .nav-links a {
    display: block;
    padding: 16px 0;
    font-size: 1.1rem;
    border-bottom: 1px solid var(--color-border);
  }

  .mobile-toggle {
    display: flex;
  }

  .hero {
    min-height: auto;
    padding: calc(var(--nav-height) + 40px) 0 60px;
  }

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

  .btn {
    width: 100%;
  }

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

  .service-cards {
    grid-template-columns: 1fr;
  }

  .portfolio-card {
    grid-template-columns: 1fr;
    gap: 20px;
    padding: 28px;
  }

  .portfolio-visual {
    width: 56px;
    height: 56px;
  }

  .footer-inner {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .shape-grid {
    width: 180px;
    height: 180px;
    gap: 12px;
  }

  .shape {
    border-radius: 14px;
  }

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

  .stat-item {
    padding: 24px;
  }
}