/* ============================================
   长沙智梦思维网络科技有限公司 - 门户网站样式
   ============================================ */

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #1a6cf0;
  --primary-dark: #1356c7;
  --primary-light: #e8f1ff;
  --accent: #00b4d8;
  --dark: #1a1a2e;
  --dark2: #16213e;
  --gray: #6c757d;
  --light: #f8f9fa;
  --white: #ffffff;
  --border: #e9ecef;
  --shadow: 0 4px 20px rgba(0,0,0,.08);
  --shadow-lg: 0 10px 40px rgba(0,0,0,.12);
  --radius: 12px;
  --radius-sm: 8px;
  --transition: all .3s ease;
  --max-width: 1200px;
}

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: #333;
  background: var(--white);
  overflow-x: hidden;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--primary); text-decoration: none; transition: var(--transition); }
a:hover { color: var(--primary-dark); }
ul { list-style: none; }

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

/* --- Buttons --- */
.btn {
  display: inline-block; padding: 12px 32px; font-size: 15px; font-weight: 600;
  border-radius: 50px; cursor: pointer; border: none; transition: var(--transition);
  text-align: center; letter-spacing: .5px;
}
.btn-primary {
  background: var(--primary); color: var(--white);
  box-shadow: 0 4px 15px rgba(26,108,240,.35);
}
.btn-primary:hover { background: var(--primary-dark); color: var(--white); transform: translateY(-2px); box-shadow: 0 6px 20px rgba(26,108,240,.45); }
.btn-outline {
  background: transparent; color: var(--primary); border: 2px solid var(--primary);
}
.btn-outline:hover { background: var(--primary); color: var(--white); }
.btn-light { background: var(--white); color: var(--primary); }
.btn-light:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }

/* --- Header --- */
.header {
  position: fixed; top: 0; left: 0; width: 100%; z-index: 1000;
  background: rgba(255,255,255,.97); backdrop-filter: blur(10px);
  box-shadow: 0 1px 0 var(--border); transition: var(--transition);
}
.header.scrolled { box-shadow: var(--shadow); }

.header .container { display: flex; align-items: center; justify-content: space-between; height: 70px; }

.logo { display: flex; align-items: center; gap: 10px; font-size: 22px; font-weight: 700; color: var(--dark); }
.logo-icon {
  width: 42px; height: 42px; background: linear-gradient(135deg, var(--primary), var(--accent));
  border-radius: 10px; display: flex; align-items: center; justify-content: center;
  color: var(--white); font-size: 20px; font-weight: 800;
}
.logo span { color: var(--primary); }

.nav { display: flex; align-items: center; gap: 32px; }
.nav a {
  color: var(--dark); font-size: 15px; font-weight: 500; position: relative; padding: 4px 0;
}
.nav a::after {
  content: ''; position: absolute; bottom: -2px; left: 0; width: 0; height: 2px;
  background: var(--primary); transition: width .3s ease;
}
.nav a:hover::after, .nav a.active::after { width: 100%; }
.nav a:hover, .nav a.active { color: var(--primary); }

.menu-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 10px; }
.menu-toggle span { width: 26px; height: 2.5px; background: var(--dark); border-radius: 2px; transition: var(--transition); }
.menu-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.menu-toggle.active span:nth-child(2) { opacity: 0; }
.menu-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* --- Hero --- */
.hero {
  padding: 160px 0 120px;
  background: linear-gradient(135deg, #f0f5ff 0%, #e8f4f8 50%, #f5f0ff 100%);
  position: relative; overflow: hidden;
}
.hero::before {
  content: ''; position: absolute; top: -50%; right: -20%;
  width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(26,108,240,.08) 0%, transparent 70%);
  border-radius: 50%;
}
.hero::after {
  content: ''; position: absolute; bottom: -30%; left: -10%;
  width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(0,180,216,.08) 0%, transparent 70%);
  border-radius: 50%;
}
.hero .container { position: relative; z-index: 1; display: flex; align-items: center; gap: 60px; }

.hero-text { flex: 1; }
.hero-badge {
  display: inline-block; padding: 6px 18px; background: var(--primary-light);
  color: var(--primary); border-radius: 50px; font-size: 13px; font-weight: 600;
  margin-bottom: 20px; letter-spacing: 1px;
}
.hero h1 { font-size: 48px; font-weight: 800; color: var(--dark); line-height: 1.25; margin-bottom: 20px; }
.hero h1 span { color: var(--primary); }
.hero p { font-size: 18px; color: var(--gray); margin-bottom: 36px; max-width: 520px; line-height: 1.8; }
.hero-btns { display: flex; gap: 16px; flex-wrap: wrap; }

.hero-img { flex: 1; display: flex; justify-content: center; align-items: center; }
.hero-graphic {
  width: 420px; height: 380px; background: var(--white); border-radius: 24px;
  box-shadow: var(--shadow-lg); display: flex; align-items: center; justify-content: center;
  position: relative;
}
.hero-graphic::after {
  content: ''; position: absolute; width: 100%; height: 100%;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  border-radius: 24px; top: 16px; left: 16px; z-index: -1; opacity: .3;
}
.graph-inner { text-align: center; }
.graph-inner .big-icon { font-size: 80px; margin-bottom: 16px; }
.graph-inner .graph-title { font-size: 22px; font-weight: 700; color: var(--dark); }
.graph-inner .graph-sub { font-size: 14px; color: var(--gray); margin-top: 8px; }

.hero-stats {
  display: flex; gap: 48px; margin-top: 60px; padding-top: 40px; border-top: 1px solid var(--border);
}
.stat-item h3 { font-size: 36px; font-weight: 800; color: var(--primary); }
.stat-item p { font-size: 14px; color: var(--gray); margin: 0; }

/* --- Section Common --- */
.section { padding: 100px 0; }
.section-gray { background: var(--light); }

.section-header { text-align: center; margin-bottom: 64px; }
.section-header h2 { font-size: 36px; font-weight: 800; color: var(--dark); margin-bottom: 12px; }
.section-header h2 span { color: var(--primary); }
.section-header .subtitle { font-size: 17px; color: var(--gray); max-width: 600px; margin: 0 auto; margin-top: 8px; }
.bar {
  width: 60px; height: 4px; background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px; margin: 0 auto 12px;
}

/* --- About --- */
.about-content { display: flex; align-items: center; gap: 60px; }
.about-text { flex: 1; }
.about-text h3 { font-size: 28px; font-weight: 700; color: var(--dark); margin-bottom: 20px; }
.about-text p { color: var(--gray); margin-bottom: 16px; line-height: 1.9; }
.about-features { display: flex; flex-wrap: wrap; gap: 12px; margin: 28px 0; }
.about-feature {
  display: flex; align-items: center; gap: 8px; background: var(--light);
  padding: 10px 18px; border-radius: var(--radius-sm); font-size: 14px; font-weight: 500; color: var(--dark);
}
.about-feature .dot { width: 8px; height: 8px; background: var(--primary); border-radius: 50%; }

.about-img { flex: 1; }
.about-card {
  background: var(--white); border-radius: var(--radius); padding: 40px;
  box-shadow: var(--shadow); border-left: 4px solid var(--primary);
}
.about-card h4 { font-size: 20px; color: var(--dark); margin-bottom: 12px; }
.about-card ul li {
  padding: 8px 0; color: var(--gray); border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 8px;
}
.about-card ul li:last-child { border-bottom: none; }
.about-card ul li::before { content: '✓'; color: var(--primary); font-weight: 700; }

/* --- Services --- */
.services-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px;
}
.service-card {
  background: var(--white); border-radius: var(--radius); padding: 40px 30px;
  box-shadow: var(--shadow); transition: var(--transition);
  text-align: center; border: 1px solid transparent;
}
.service-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lg); border-color: var(--primary-light); }
.service-icon {
  width: 70px; height: 70px; border-radius: 20px; display: flex; align-items: center;
  justify-content: center; margin: 0 auto 24px; font-size: 32px;
}
.icon-blue { background: #e8f1ff; }
.icon-cyan { background: #e0f7fa; }
.icon-purple { background: #f3e8ff; }
.icon-orange { background: #fff3e0; }
.icon-green { background: #e8f5e9; }
.icon-pink { background: #fce4ec; }

.service-card h3 { font-size: 20px; font-weight: 700; color: var(--dark); margin-bottom: 12px; }
.service-card p { color: var(--gray); font-size: 14px; line-height: 1.8; }

/* --- Advantages --- */
.advantages-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px;
}
.advantage-card {
  text-align: center; padding: 32px 20px;
  background: var(--white); border-radius: var(--radius); transition: var(--transition);
}
.advantage-card:hover { box-shadow: var(--shadow); }
.advantage-num { font-size: 42px; font-weight: 800; color: var(--primary); opacity: .15; margin-bottom: -20px; }
.advantage-card h3 { font-size: 18px; font-weight: 700; color: var(--dark); margin: 16px 0 8px; }
.advantage-card p { color: var(--gray); font-size: 14px; }

/* --- Team --- */
.team-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.team-card {
  background: var(--white); border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow); text-align: center; transition: var(--transition);
}
.team-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.team-avatar {
  width: 100%; height: 200px; display: flex; align-items: center; justify-content: center;
  font-size: 64px; color: var(--white);
}
.avatar-1 { background: linear-gradient(135deg, #667eea, #764ba2); }
.avatar-2 { background: linear-gradient(135deg, #f093fb, #f5576c); }
.avatar-3 { background: linear-gradient(135deg, #4facfe, #00f2fe); }
.avatar-4 { background: linear-gradient(135deg, #43e97b, #38f9d7); }
.team-info { padding: 24px 16px; }
.team-info h4 { font-size: 18px; font-weight: 700; color: var(--dark); }
.team-info .role { font-size: 13px; color: var(--primary); font-weight: 600; margin: 4px 0 10px; }
.team-info p { font-size: 13px; color: var(--gray); }

/* --- Cases / Portfolio --- */
.cases-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.case-card {
  background: var(--white); border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow); transition: var(--transition);
}
.case-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.case-thumb {
  height: 200px; display: flex; align-items: center; justify-content: center;
  font-size: 48px; color: var(--white); font-weight: 700;
}
.case-1 { background: linear-gradient(135deg, #667eea, #764ba2); }
.case-2 { background: linear-gradient(135deg, #f093fb, #f5576c); }
.case-3 { background: linear-gradient(135deg, #4facfe, #00f2fe); }
.case-info { padding: 24px; }
.case-info .tag { font-size: 12px; color: var(--primary); font-weight: 600; text-transform: uppercase; letter-spacing: 1px; }
.case-info h4 { font-size: 18px; font-weight: 700; color: var(--dark); margin: 8px 0; }
.case-info p { font-size: 14px; color: var(--gray); }

/* --- Contact --- */
.contact-wrap { display: flex; gap: 48px; align-items: flex-start; }
.contact-info { flex: 1; }
.contact-info h3 { font-size: 28px; font-weight: 700; color: var(--dark); margin-bottom: 12px; }
.contact-info > p { color: var(--gray); margin-bottom: 32px; }
.contact-items { display: flex; flex-direction: column; gap: 20px; }
.contact-item { display: flex; gap: 16px; align-items: flex-start; }
.contact-icon {
  width: 48px; height: 48px; min-width: 48px; border-radius: 12px;
  background: var(--primary-light); display: flex; align-items: center;
  justify-content: center; font-size: 22px; color: var(--primary);
}
.contact-item h4 { font-size: 16px; font-weight: 700; color: var(--dark); margin-bottom: 4px; }
.contact-item p { font-size: 14px; color: var(--gray); }

.contact-form-wrap { flex: 1; }
.contact-form {
  background: var(--white); padding: 36px; border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-size: 14px; font-weight: 600; color: var(--dark); margin-bottom: 6px; }
.form-group input, .form-group textarea {
  width: 100%; padding: 12px 16px; border: 2px solid var(--border);
  border-radius: var(--radius-sm); font-size: 15px; font-family: inherit;
  transition: var(--transition); outline: none; background: var(--light);
}
.form-group input:focus, .form-group textarea:focus {
  border-color: var(--primary); background: var(--white);
}
.form-group textarea { resize: vertical; min-height: 120px; }

/* --- Footer --- */
.footer {
  background: var(--dark); color: rgba(255,255,255,.7); padding: 60px 0 0;
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 48px;
  margin-bottom: 48px;
}
.footer-col h4 { font-size: 18px; font-weight: 700; color: var(--white); margin-bottom: 20px; }
.footer-col p { font-size: 14px; line-height: 1.9; margin-bottom: 16px; }
.footer-col ul li { margin-bottom: 10px; }
.footer-col ul li a { color: rgba(255,255,255,.6); font-size: 14px; }
.footer-col ul li a:hover { color: var(--white); }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.1); padding: 24px 0;
  text-align: center; font-size: 14px;
}
.footer-bottom a { color: var(--primary); }

/* --- Back to Top --- */
.back-top {
  position: fixed; bottom: 32px; right: 32px; width: 44px; height: 44px;
  background: var(--primary); color: var(--white); border: none; border-radius: 50%;
  font-size: 18px; cursor: pointer; box-shadow: 0 4px 15px rgba(26,108,240,.4);
  opacity: 0; visibility: hidden; transform: translateY(20px); transition: var(--transition);
  z-index: 999; display: flex; align-items: center; justify-content: center;
}
.back-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top:hover { background: var(--primary-dark); transform: translateY(-4px); }

/* --- Animations --- */
.fade-in { opacity: 0; transform: translateY(30px); transition: all .6s ease; }
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* --- Responsive --- */
@media (max-width: 1024px) {
  .services-grid { grid-template-columns: repeat(2, 1fr); }
  .advantages-grid, .team-grid { grid-template-columns: repeat(2, 1fr); }
  .hero .container { flex-direction: column; text-align: center; }
  .hero p { margin: 0 auto 36px; }
  .hero-btns { justify-content: center; }
  .hero-stats { justify-content: center; }
  .hero-graphic { width: 320px; height: 280px; }
  .about-content { flex-direction: column; }
  .about-features { justify-content: center; }
  .contact-wrap { flex-direction: column; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .cases-grid { grid-template-columns: repeat(2, 1fr); }

  .nav {
    display: none;
    position: fixed; top: 70px; left: 0; width: 100%;
    max-height: calc(100vh - 70px);
    background: var(--white); flex-direction: column; padding: 24px;
    box-shadow: var(--shadow);
    z-index: 1001; overflow-y: auto;
  }
  .nav.open { display: flex; animation: navSlideIn .3s ease; }
  @keyframes navSlideIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
  }
  .menu-toggle { display: flex; z-index: 1002; position: relative; }
}

@media (max-width: 768px) {
  .hero h1 { font-size: 32px; }
  .services-grid, .advantages-grid, .team-grid { grid-template-columns: 1fr; }
  .cases-grid, .footer-grid { grid-template-columns: 1fr; }
  .hero-stats { flex-wrap: wrap; gap: 24px; }
  .section { padding: 64px 0; }
  .section-header h2 { font-size: 28px; }
}