/* ========== 全局变量与暗色模式 ========== */
:root {
  --bg-color: #f8fafc;
  --text-color: #0f172a;
  --text-secondary: #475569;
  --card-bg: #ffffff;
  --border-color: #eef2f6;
  --navbar-bg: rgba(255,255,255,0.7);
  --tag-bg: #f1f5f9;
  --shadow: 0 8px 20px rgba(0,0,0,0.02);
  --highlight: #2563eb;
}

[data-theme="dark"] {
  --bg-color: #0b1120;
  --text-color: #e2e8f0;
  --text-secondary: #94a3b8;
  --card-bg: #1e293b;
  --border-color: #334155;
  --navbar-bg: rgba(15,23,42,0.8);
  --tag-bg: #334155;
  --shadow: 0 8px 20px rgba(0,0,0,0.3);
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background 0.3s, color 0.2s;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 2;
}

/* ----- 鼠标跟随光效 ----- */
.mouse-glow {
  position: fixed;
  width: 400px;
  height: 400px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(37,99,235,0.15) 0%, rgba(37,99,235,0) 70%);
  pointer-events: none;
  z-index: 9999;
  transform: translate(-50%, -50%);
  transition: opacity 0.2s;
  opacity: 0;
  mix-blend-mode: screen;
}

body:hover .mouse-glow {
  opacity: 1;
}

/* ----- 粒子背景 ----- */
#particle-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
  opacity: 0.25;
}

/* 导航栏 */
.navbar {
  padding: 18px 0;
  border-bottom: 1px solid var(--border-color);
  background: var(--navbar-bg);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 100;
  transition: background 0.3s, box-shadow 0.3s;
}

.navbar.scrolled {
  background: var(--navbar-bg);
  box-shadow: 0 4px 20px rgba(0,0,0,0.05);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-weight: 600;
  font-size: 1.4rem;
  letter-spacing: -0.5px;
  color: var(--text-color);
  transition: transform 0.2s;
}

.logo:hover {
  transform: scale(1.02);
}

.nav-links {
  display: flex;
  gap: 2.2rem;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-color);
  font-weight: 500;
  transition: color 0.2s, transform 0.1s;
  display: inline-block;
}

.nav-links a:hover {
  color: var(--highlight);
  transform: translateY(-1px);
}

/* 主题切换按钮 */
.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.3rem;
  color: var(--text-color);
  margin-left: 20px;
  transition: transform 0.2s;
  display: flex;
  align-items: center;
}
.theme-toggle:hover {
  transform: rotate(20deg);
}

/* 各部分 */
section {
  padding: 70px 0;
  position: relative;
  z-index: 2;
}

h2 {
  font-size: 2rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 36px;
  color: var(--text-color);
  border-bottom: 3px solid var(--highlight);
  padding-bottom: 10px;
  display: inline-block;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

h2.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Hero */
.hero {
  display: flex;
  align-items: center;
  gap: 50px;
  flex-wrap: wrap;
}

.hero-content {
  flex: 1;
  opacity: 0;
  transform: translateX(-20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.hero-content.visible {
  opacity: 1;
  transform: translateX(0);
}

.badge {
  background: #dbeafe;
  color: #1e40af;
  padding: 4px 12px;
  border-radius: 30px;
  font-size: 0.9rem;
  font-weight: 500;
  display: inline-block;
  margin-bottom: 16px;
  transition: background 0.2s;
}

.badge:hover {
  background: #c7d9f7;
}

.hero-content h1 {
  font-size: 3.2rem;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.03em;
  margin-bottom: 18px;
  color: var(--text-color);
}

.highlight {
  color: var(--highlight);
}

.hero-desc {
  font-size: 1.2rem;
  color: var(--text-secondary);
  margin-bottom: 28px;
  max-width: 550px;
}

.hero-avatar {
  width: 220px;
  height: 220px;
  border-radius: 24px;
  object-fit: cover;
  box-shadow: 0 25px 30px -12px rgba(0,0,0,0.15);
  border: 3px solid white;
  background: #cbd5e1;
  opacity: 0;
  transform: scale(0.9);
  transition: opacity 0.6s ease, transform 0.6s ease, box-shadow 0.3s;
}

.hero-avatar.visible {
  opacity: 1;
  transform: scale(1);
}

.hero-avatar:hover {
  box-shadow: 0 30px 40px -10px rgba(37,99,235,0.2);
}

.btn-group {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: 60px;
  text-decoration: none;
  font-weight: 500;
  transition: all 0.2s;
  will-change: transform;
}

.btn-primary {
  background: var(--highlight);
  color: white;
  box-shadow: 0 8px 16px -6px rgba(37,99,235,0.25);
}

.btn-primary:hover {
  background: #1d4ed8;
  transform: translateY(-3px);
  box-shadow: 0 12px 20px -8px rgba(37,99,235,0.4);
}

.btn-outline {
  border: 1.5px solid #cbd5e1;
  color: var(--text-color);
}

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

/* 项目卡片网格 */
.project-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.project-card {
  background: var(--card-bg);
  border-radius: 24px;
  padding: 28px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border-color);
  transition: all 0.3s cubic-bezier(0.2,0,0,1);
  opacity: 0;
  transform: translateY(30px);
  will-change: transform, opacity, box-shadow;
}

.project-card.visible {
  opacity: 1;
  transform: translateY(0);
}

.project-card:hover {
  box-shadow: 0 20px 30px -8px rgba(0,0,0,0.12);
  border-color: #dbeafe;
  transform: translateY(-8px) !important;
}

.project-icon {
  font-size: 2.2rem;
  color: var(--highlight);
  margin-bottom: 18px;
  transition: transform 0.2s;
}

.project-card:hover .project-icon {
  transform: scale(1.05);
}

.project-card h3 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text-color);
}

.project-card p {
  color: var(--text-secondary);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 16px 0;
}

.tag {
  background: var(--tag-bg);
  padding: 4px 12px;
  border-radius: 30px;
  font-size: 0.8rem;
  color: var(--text-secondary);
  transition: background 0.2s;
}

.tag:hover {
  background: #e2e8f0;
}

.project-link {
  margin-top: 20px;
  display: flex;
  gap: 20px;
}

.project-link a {
  text-decoration: none;
  color: var(--highlight);
  font-weight: 500;
  font-size: 0.95rem;
  transition: transform 0.15s;
  display: inline-block;
}

.project-link a:hover {
  transform: translateX(3px);
}

.project-link a i {
  margin-right: 6px;
}

/* 技能标签区 */
.skills-container {
  display: flex;
  flex-wrap: wrap;
  gap: 30px;
  background: var(--card-bg);
  padding: 30px 34px;
  border-radius: 28px;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow);
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.skills-container.visible {
  opacity: 1;
  transform: translateY(0);
}

.skill-category {
  flex: 1;
}

.skill-category h4 {
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text-color);
}

.skill-items {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.skill-item {
  background: var(--tag-bg);
  padding: 6px 16px;
  border-radius: 40px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: all 0.2s;
  cursor: default;
}

.skill-item:hover {
  background: var(--highlight);
  color: white;
  transform: scale(1.05);
}

/* 社交链接 */
.social-links {
  display: flex;
  gap: 30px;
  margin-top: 30px;
}

.social-link {
  font-size: 1.8rem;
  color: #64748b;
  transition: color 0.2s, transform 0.2s;
  display: inline-block;
}

.social-link:hover {
  color: var(--highlight);
  transform: translateY(-5px);
}

.footer {
  padding: 30px 0;
  text-align: center;
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  margin-top: 20px;
}

/* 响应式 */
@media (max-width: 768px) {
  .hero {
    flex-direction: column-reverse;
    text-align: center;
  }
  .hero-content h1 {
    font-size: 2.5rem;
  }
  .btn-group {
    justify-content: center;
  }
  .project-grid {
    grid-template-columns: 1fr;
  }
  .nav-links {
    gap: 1.2rem;
  }
  .skills-container {
    flex-direction: column;
    gap: 20px;
  }
}

/* 渐入动画基础类 */
.fade-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* 加载占位样式 */
.loading-placeholder {
  grid-column: 1 / -1;
  text-align: center;
  padding: 40px;
  color: var(--text-secondary);
}