/* ===== CSS 变量定义 ===== */
:root {
  /* 颜色系统 */
  --primary-50: #eff6ff;
  --primary-100: #dbeafe;
  --primary-200: #bfdbfe;
  --primary-300: #93c5fd;
  --primary-400: #60a5fa;
  --primary-500: #3b82f6;
  --primary-600: #2563eb;
  --primary-700: #1d4ed8;
  --primary-800: #1e40af;
  --primary-900: #1e3a8a;

  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;

  /* 语义化颜色 */
  --color-primary: var(--primary-600);
  --color-primary-hover: var(--primary-700);
  --color-text: var(--gray-900);
  --color-text-secondary: var(--gray-600);
  --color-text-muted: var(--gray-500);
  --color-bg: #ffffff;
  --color-bg-secondary: var(--gray-50);
  --color-bg-tertiary: var(--gray-100);
  --color-border: var(--gray-200);
  --color-border-light: var(--gray-100);

  /* 渐变 */
  --gradient-primary: linear-gradient(135deg, var(--primary-600) 0%, var(--primary-800) 100%);
  --gradient-secondary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --gradient-accent: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);

  /* 阴影 */
  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

  /* 间距 */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* 字体 */
  --font-family-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;

  /* 字体大小 */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;
  --text-6xl: 3.75rem;

  /* 行高 */
  --leading-tight: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;

  /* 圆角 */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-2xl: 1rem;
  --radius-full: 9999px;

  /* 过渡 */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;

  /* Z-index */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal: 1040;
  --z-popover: 1050;
  --z-tooltip: 1060;
}

/* 深色模式 */
[data-theme="dark"] {
  --color-text: var(--gray-100);
  --color-text-secondary: var(--gray-300);
  --color-text-muted: var(--gray-400);
  --color-bg: var(--gray-900);
  --color-bg-secondary: var(--gray-800);
  --color-bg-tertiary: var(--gray-700);
  --color-border: var(--gray-700);
  --color-border-light: var(--gray-600);
}

/* ===== 基础重置 ===== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-family-sans);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

/* ===== 通用组件 ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

@media (min-width: 640px) {
  .container {
    padding: 0 var(--space-lg);
  }
}

@media (min-width: 1024px) {
  .container {
    padding: 0 var(--space-xl);
  }
}

/* 按钮组件 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  border: none;
  border-radius: var(--radius-lg);
  font-size: var(--text-base);
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--gradient-primary);
  color: white;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: white;
  transform: translateY(-2px);
}

/* ===== 导航栏 ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border-light);
  z-index: var(--z-fixed);
  transition: all var(--transition-normal);
}

[data-theme="dark"] .navbar {
  background: rgba(17, 24, 39, 0.95);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4rem;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-primary);
  text-decoration: none;
}

.brand-icon {
  width: 2rem;
  height: 2rem;
  background: var(--gradient-primary);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: var(--space-xl);
}

.nav-link {
  color: var(--color-text);
  text-decoration: none;
  font-weight: 500;
  padding: var(--space-sm) 0;
  position: relative;
  transition: color var(--transition-normal);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width var(--transition-normal);
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.theme-toggle {
  width: 2.5rem;
  height: 2.5rem;
  border: none;
  border-radius: var(--radius-full);
  background: var(--color-bg-secondary);
  color: var(--color-text);
  cursor: pointer;
  transition: all var(--transition-normal);
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle:hover {
  background: var(--color-bg-tertiary);
  transform: scale(1.1);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: var(--color-text);
  transition: all var(--transition-normal);
}

/* ===== 英雄区域 ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  background: var(--gradient-secondary);
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  opacity: 0.1;
}

.hero-shapes {
  position: relative;
  width: 100%;
  height: 100%;
}

.shape {
  position: absolute;
  border-radius: var(--radius-2xl);
  background: rgba(255, 255, 255, 0.1);
  animation: float 6s ease-in-out infinite;
}

.shape-1 {
  width: 200px;
  height: 200px;
  top: 10%;
  left: 10%;
  animation-delay: 0s;
}

.shape-2 {
  width: 150px;
  height: 150px;
  top: 60%;
  right: 10%;
  animation-delay: 2s;
}

.shape-3 {
  width: 100px;
  height: 100px;
  bottom: 20%;
  left: 20%;
  animation-delay: 4s;
}

@keyframes float {
  0%, 100% {
    transform: translateY(0px) rotate(0deg);
  }
  50% {
    transform: translateY(-20px) rotate(5deg);
  }
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-title {
  font-size: var(--text-5xl);
  font-weight: 800;
  line-height: var(--leading-tight);
  margin-bottom: var(--space-lg);
  color: white;
}

.title-line {
  display: block;
}

.title-highlight {
  background: linear-gradient(45deg, #fbbf24, #f59e0b);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-description {
  font-size: var(--text-lg);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-xl);
  color: rgba(255, 255, 255, 0.9);
}

.hero-actions {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.visual-container {
  position: relative;
  width: 300px;
  height: 300px;
}

.floating-element {
  position: absolute;
  width: 60px;
  height: 60px;
  background: rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: var(--text-xl);
  animation: orbit 8s linear infinite;
}

.element-1 {
  top: 20%;
  left: 20%;
  animation-delay: 0s;
}

.element-2 {
  top: 20%;
  right: 20%;
  animation-delay: 2s;
}

.element-3 {
  bottom: 20%;
  left: 20%;
  animation-delay: 4s;
}

.element-4 {
  bottom: 20%;
  right: 20%;
  animation-delay: 6s;
}

.central-element {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 80px;
  height: 80px;
  background: var(--gradient-primary);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: var(--text-2xl);
  box-shadow: var(--shadow-xl);
}

@keyframes orbit {
  0% {
    transform: rotate(0deg) translateX(50px) rotate(0deg);
  }
  100% {
    transform: rotate(360deg) translateX(50px) rotate(-360deg);
  }
}

/* ===== 区域样式 ===== */
.about,
.services,
.portfolio,
.contact {
  padding: var(--space-3xl) 0;
}

.about {
  background: var(--color-bg-secondary);
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.section-title {
  font-size: var(--text-4xl);
  font-weight: 700;
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.section-subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
}

.about-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-xl);
}

.about-card {
  background: var(--color-bg);
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
  text-align: center;
  transition: transform var(--transition-normal);
}

.about-card:hover {
  transform: translateY(-5px);
}

.card-icon {
  width: 4rem;
  height: 4rem;
  background: var(--gradient-primary);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--space-lg);
  color: white;
  font-size: var(--text-xl);
}

.about-card h3 {
  font-size: var(--text-xl);
  font-weight: 600;
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.about-card p {
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
}

/* 服务区域 */
.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-xl);
}

.service-card {
  background: var(--color-bg);
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
  border: 1px solid var(--color-border);
}

.service-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.service-icon {
  width: 3rem;
  height: 3rem;
  background: var(--gradient-accent);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-lg);
  color: white;
  font-size: var(--text-lg);
}

.service-card h3 {
  font-size: var(--text-xl);
  font-weight: 600;
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.service-card p {
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-lg);
}

.service-link {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  transition: gap var(--transition-normal);
}

.service-link:hover {
  gap: var(--space-md);
}

/* 作品展示区域 */
.portfolio {
  background: var(--color-bg-secondary);
}

.portfolio-placeholder {
  text-align: center;
  padding: var(--space-3xl);
}

.placeholder-content i {
  font-size: var(--text-5xl);
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
}

.placeholder-content h3 {
  font-size: var(--text-2xl);
  font-weight: 600;
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.placeholder-content p {
  color: var(--color-text-secondary);
  font-size: var(--text-lg);
}

/* 联系区域 */
.contact-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  align-items: start;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.contact-icon {
  width: 3rem;
  height: 3rem;
  background: var(--gradient-primary);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: var(--text-lg);
}

.contact-details h4 {
  font-size: var(--text-lg);
  font-weight: 600;
  margin-bottom: var(--space-xs);
  color: var(--color-text);
}

.contact-details p {
  color: var(--color-text-secondary);
}

.contact-form {
  background: var(--color-bg);
  padding: var(--space-xl);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
}

.form-group {
  margin-bottom: var(--space-lg);
}

.form-group label {
  display: block;
  margin-bottom: var(--space-sm);
  font-weight: 500;
  color: var(--color-text);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  font-size: var(--text-base);
  background: var(--color-bg);
  color: var(--color-text);
  transition: border-color var(--transition-normal);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
}

/* ===== 页脚 ===== */
.footer {
  background: var(--color-bg-secondary);
  padding: var(--space-3xl) 0 var(--space-lg);
  border-top: 1px solid var(--color-border);
}

.footer-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3xl);
  margin-bottom: var(--space-xl);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.footer-description {
  color: var(--color-text-secondary);
  margin-top: var(--space-md);
}

.footer-links {
  display: flex;
  gap: var(--space-3xl);
}

.footer-section h4 {
  font-size: var(--text-lg);
  font-weight: 600;
  margin-bottom: var(--space-lg);
  color: var(--color-text);
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: var(--space-sm);
}

.footer-section ul li a {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-normal);
}

.footer-section ul li a:hover {
  color: var(--color-primary);
}

.social-links {
  display: flex;
  gap: var(--space-md);
}

.social-links a {
  width: 2.5rem;
  height: 2.5rem;
  background: var(--color-bg-tertiary);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text);
  text-decoration: none;
  transition: all var(--transition-normal);
}

.social-links a:hover {
  background: var(--color-primary);
  color: white;
  transform: translateY(-2px);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
  color: var(--color-text-secondary);
}

/* ===== 返回顶部按钮 ===== */
.back-to-top {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  width: 3rem;
  height: 3rem;
  background: var(--gradient-primary);
  border: none;
  border-radius: var(--radius-full);
  color: white;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  transition: all var(--transition-normal);
  opacity: 0;
  visibility: hidden;
  z-index: var(--z-fixed);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-xl);
}

/* ===== 响应式设计 ===== */
@media (max-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
    gap: var(--space-xl);
  }

  .contact-content {
    grid-template-columns: 1fr;
  }

  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .footer-links {
    justify-content: center;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: 4rem;
    left: -100%;
    width: 100%;
    height: calc(100vh - 4rem);
    background: var(--color-bg);
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    padding: var(--space-xl);
    transition: left var(--transition-normal);
    box-shadow: var(--shadow-lg);
  }

  .nav-menu.active {
    left: 0;
  }

  .nav-toggle {
    display: flex;
  }

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

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

  .nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
  }

  .hero-title {
    font-size: var(--text-4xl);
  }

  .section-title {
    font-size: var(--text-3xl);
  }

  .about-grid,
  .services-grid {
    grid-template-columns: 1fr;
  }

  .footer-links {
    flex-direction: column;
    gap: var(--space-xl);
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--space-sm);
  }

  .hero-title {
    font-size: var(--text-3xl);
  }

  .hero-actions {
    flex-direction: column;
    align-items: center;
  }

  .btn {
    width: 100%;
    max-width: 200px;
  }
}

/* ===== 滚动条样式 ===== */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-muted);
}

/* ===== 选择文本样式 ===== */
::selection {
  background: var(--primary-200);
  color: var(--primary-900);
}

/* ===== 焦点样式 ===== */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ===== 动画优化 ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}