:root {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --accent-primary: #3b82f6;
  --accent-secondary: #8b5cf6;
  --shadow:
    0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-hover:
    0 10px 15px -3px rgba(0, 0, 0, 0.1),
    0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --border-radius: 8px;
  --transition: all 0.3s ease;
}
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
}
body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}
/* 导航栏 */
header {
  background-color: var(--bg-secondary);
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}
nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
  flex-wrap: wrap;
  gap: 1rem;
}
.logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--accent-primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.logo-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--accent-primary);
}
.nav-links {
  display: flex;
  list-style: none;
  gap: 1.5rem;
  flex-wrap: wrap;
}
.nav-links a {
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 500;
  transition: var(--transition);
}
.nav-links a:hover {
  color: var(--accent-primary);
}
/* 英雄区 */
.hero {
  padding: 5rem 0 4rem;
  text-align: center;
  background: linear-gradient(135deg, var(--bg-primary) 0%, #e2e8f0 100%);
}
.hero .subtitle {
  font-size: 2rem;
  color: var(--accent-primary);
  margin-bottom: 1rem;
  font-weight: 600;
}
.hero p {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2rem;
}
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background-color: var(--accent-primary);
  color: white;
  border-radius: 30px;
  text-decoration: none;
  font-weight: 500;
  transition: var(--transition);
}
.btn:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}
/* 通用部分样式 */
.section {
  padding: 4rem 0;
}
.section-lg {
  padding: 6rem 0;
}
.section-title {
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: 3rem;
  color: var(--text-primary);
  font-weight: bold;
  position: relative;
}
.section-title::after {
  content: "";
  display: block;
  width: 80px;
  height: 4px;
  background: linear-gradient(
    90deg,
    var(--accent-primary),
    var(--accent-secondary)
  );
  margin: 1rem auto 0;
  border-radius: 2px;
}
.card {
  background-color: var(--bg-secondary);
  border-radius: 24px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-hover);
}
.card {
  background-color: var(--bg-secondary);
  border-radius: 24px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
  position: relative;
}
.card-image-container {
  position: relative;
  height: 200px;
  overflow: hidden;
}
.card-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: var(--transition);
}
.card-image-container::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100px;
  background: linear-gradient(to bottom, transparent 0%, rgba(255, 255, 255, 0.5) 50%, white 100%);
  pointer-events: none;
  z-index: 1;
}
.card-content {
  padding: 1.5rem;
  background-color: white;
  position: relative;
  z-index: 2;
  margin-top: -1px;
}
.card-title {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
  font-weight: bold;
}
.card-description {
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  line-height: 1.5;
  font-size: 0.95rem;
}
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}
.tag {
  padding: 0.25rem 0.75rem;
  background-color: #e2e8f0;
  border-radius: 16px;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-primary);
}
.link-list {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}
.link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--accent-primary);
  font-weight: 500;
  transition: var(--transition);
}
.link:hover {
  color: var(--accent-secondary);
  text-decoration: underline;
}

/* 项目展示区 - 网格布局 */
.projects {
  padding: 6rem 0;
}
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 2.5rem;
}

/* 技术栈卡片网格 */
.tech-stack {
  background-color: var(--bg-secondary);
}
.tech-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(100px, 120px));
  gap: 1.5rem;
  justify-content: center;
  margin-top: 2rem;
}
.tech-card {
  background-color: var(--bg-primary);
  border-radius: 16px;
  padding: 1rem 0.5rem;
  text-align: center;
  transition: var(--transition);
  box-shadow: var(--shadow);
}
.tech-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  background-color: var(--accent-primary);
  color: white;
}
.tech-card i {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  display: block;
}
.tech-card span {
  font-size: 0.85rem;
  font-weight: 500;
}
/* 关于我 */
.about {
  background-color: var(--bg-primary);
}
.about-content {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
  color: var(--text-secondary);
  font-style: italic;
}
/* 联系区 */
.contact {
  background-color: var(--bg-secondary);
}
.social-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-top: 2rem;
}
.social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background-color: #e2e8f0;
  color: var(--text-primary);
  transition: var(--transition);
  text-decoration: none;
}
.social-link:hover {
  background-color: var(--accent-primary);
  color: white;
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}
footer {
  background-color: var(--text-primary);
  color: white;
  text-align: center;
  padding: 2rem 0;
}
/* 滚动动画 */
.fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition:
    opacity 0.8s ease,
    transform 0.8s ease;
}
.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}
/* 回到顶部按钮 */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background-color: var(--accent-primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  box-shadow: var(--shadow);
  transition: var(--transition);
  opacity: 0;
  visibility: hidden;
  z-index: 99;
}
.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}
.back-to-top:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}
/* 响应式 */
@media (max-width: 768px) {
  nav {
    justify-content: center;
    text-align: center;
  }
  .hero .subtitle {
    font-size: 1.5rem;
  }
  .tech-grid {
    grid-template-columns: repeat(auto-fit, minmax(90px, 100px));
    gap: 1rem;
  }
  .back-to-top {
    bottom: 1rem;
    right: 1rem;
    width: 40px;
    height: 40px;
  }
}