/* ========================================
   网络技术服务官网 - 全局设计系统
   深空蓝科技风 | 响应式 | 无第三方品牌
   ======================================== */

/* --- 字体引入 --- */
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;700&display=swap');

/* --- CSS 变量 --- */
:root {
  --color-deep-blue: #0A1929;
  --color-tech-silver: #E0E7FF;
  --color-accent-yellow: #FFD966;
  --color-accent-hover: #FFC933;
  --color-text-primary: #F0F4FF;
  --color-text-secondary: #A0AEC0;
  --color-card-bg: rgba(15, 30, 55, 0.7);
  --color-glass: rgba(10, 25, 41, 0.75);
  --color-glass-border: rgba(224, 231, 255, 0.12);
  --font-heading: 'Alibaba PuHuiTi', 'Noto Sans SC', sans-serif;
  --font-body: 'Noto Sans SC', 'Source Han Sans CN', sans-serif;
  --nav-height: 72px;
  --transition-smooth: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 20px rgba(224, 231, 255, 0.15);
}

/* --- 全局重置 --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-body);
  background-color: var(--color-deep-blue);
  color: var(--color-text-primary);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition-smooth);
}

ul { list-style: none; }

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* --- 页面淡入动画 --- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeInUp 0.8s ease-out forwards;
  opacity: 0;
}

.fade-in-delay-1 { animation-delay: 0.15s; }
.fade-in-delay-2 { animation-delay: 0.3s; }
.fade-in-delay-3 { animation-delay: 0.45s; }
.fade-in-delay-4 { animation-delay: 0.6s; }

/* --- 导航栏 - 磨砂玻璃效果 --- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: var(--color-glass);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--color-glass-border);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 clamp(1.5rem, 4vw, 4rem);
  transition: var(--transition-smooth);
}

.navbar.scrolled {
  background: rgba(10, 25, 41, 0.92);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.nav-logo {
  font-size: 1.75rem;
  display: flex;
  align-items: center;
  gap: 0.25rem;
  cursor: pointer;
  user-select: none;
}

.nav-links {
  display: flex;
  gap: 2.5rem;
  align-items: center;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  position: relative;
  padding: 0.25rem 0;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent-yellow);
  transition: width 0.3s ease;
}

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

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

/* 汉堡菜单按钮 */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  z-index: 1001;
}

.hamburger span {
  width: 24px;
  height: 2px;
  background: var(--color-tech-silver);
  transition: var(--transition-smooth);
  border-radius: 2px;
}

.hamburger.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* --- 通用容器 --- */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(1.5rem, 4vw, 4rem);
}

.section-padding {
  padding: clamp(4rem, 8vw, 7rem) 0;
}

/* --- 按钮样式 --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.875rem 2.25rem;
  border-radius: 6px;
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  transition: var(--transition-smooth);
  cursor: pointer;
  border: none;
  font-family: var(--font-body);
}

.btn-primary {
  background: var(--color-accent-yellow);
  color: var(--color-deep-blue);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(255, 217, 102, 0.3);
}

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

.btn-outline:hover {
  background: rgba(224, 231, 255, 0.1);
  border-color: var(--color-text-primary);
  transform: translateY(-2px);
}

/* --- 卡片通用样式 --- */
.card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-glass-border);
  border-radius: 12px;
  padding: 2rem;
  transition: var(--transition-smooth);
  backdrop-filter: blur(10px);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-card);
  border-color: rgba(224, 231, 255, 0.25);
}

/* --- 图片 Hover 效果 --- */
.img-hover-wrapper {
  overflow: hidden;
  border-radius: 12px;
  position: relative;
}

.img-hover-wrapper img {
  transition: transform 0.6s ease, filter 0.6s ease;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.img-hover-wrapper:hover img {
  transform: scale(1.05);
  filter: brightness(1.15);
}

/* 柔焦渐变遮罩 */
.img-overlay {
  position: relative;
}

.img-overlay::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(10, 25, 41, 0) 0%,
    rgba(10, 25, 41, 0.6) 100%
  );
  pointer-events: none;
}

/* --- 页脚 --- */
.footer {
  background: #060F1A;
  border-top: 1px solid var(--color-glass-border);
  padding: 3rem 0 2rem;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.footer-address {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

.footer-copyright {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-tech-silver);
  letter-spacing: 0.05em;
  font-family: var(--font-heading);
}

.footer-social {
  display: flex;
  gap: 1rem;
}

.footer-social a {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid var(--color-glass-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  font-size: 1.1rem;
  transition: var(--transition-smooth);
}

.footer-social a:hover {
  background: var(--color-accent-yellow);
  color: var(--color-deep-blue);
  border-color: var(--color-accent-yellow);
}

/* --- 模态框 --- */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(6, 15, 26, 0.85);
  backdrop-filter: blur(8px);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition-smooth);
  padding: 1.5rem;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal-content {
  background: #0D1F35;
  border: 1px solid var(--color-glass-border);
  border-radius: 16px;
  max-width: 640px;
  width: 100%;
  padding: 2.5rem;
  position: relative;
  transform: scale(0.9) translateY(20px);
  transition: var(--transition-smooth);
}

.modal-overlay.active .modal-content {
  transform: scale(1) translateY(0);
}

.modal-close {
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid var(--color-glass-border);
  background: transparent;
  color: var(--color-text-secondary);
  font-size: 1.25rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-smooth);
}

.modal-close:hover {
  background: rgba(224, 231, 255, 0.1);
  color: var(--color-text-primary);
}

.modal-title {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: var(--color-text-primary);
}

.modal-body {
  color: var(--color-text-secondary);
  line-height: 1.8;
}

.modal-body p {
  margin-bottom: 0.75rem;
}

/* --- 响应式断点 --- */
@media (max-width: 768px) {
  :root {
    --nav-height: 64px;
  }

  .hamburger {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    background: rgba(10, 25, 41, 0.97);
    backdrop-filter: blur(20px);
    flex-direction: column;
    justify-content: center;
    gap: 2rem;
    transition: right 0.4s ease;
    border-left: 1px solid var(--color-glass-border);
  }

  .nav-links.open {
    right: 0;
  }

  .nav-links a {
    font-size: 1.1rem;
  }

  .footer-content {
    flex-direction: column;
    text-align: center;
  }

  .btn {
    padding: 0.75rem 1.75rem;
    font-size: 0.875rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 1.25rem;
  }

  .card {
    padding: 1.5rem;
  }

  .modal-content {
    padding: 1.75rem;
  }
}