/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Light Theme Colors */
  --primary-color: #6366f1;
  --secondary-color: #8b5cf6;
  --accent-color: #06b6d4;
  --text-primary: #1f2937;
  --text-secondary: #6b7280;
  --text-light: #9ca3af;
  --bg-primary: #ffffff;
  --bg-secondary: #f9fafb;
  --bg-tertiary: #f3f4f6;
  --border-color: #e5e7eb;
  --shadow-light: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-medium: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-heavy: 0 10px 25px rgba(0, 0, 0, 0.15);
  --gradient-primary: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  --gradient-accent: linear-gradient(135deg, var(--accent-color), var(--primary-color));
}

[data-theme="dark"] {
  /* Dark Theme Colors */
  --text-primary: #f9fafb;
  --text-secondary: #d1d5db;
  --text-light: #9ca3af;
  --bg-primary: #111827;
  --bg-secondary: #1f2937;
  --bg-tertiary: #374151;
  --border-color: #4b5563;
  --shadow-light: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-medium: 0 4px 6px rgba(0, 0, 0, 0.3);
  --shadow-heavy: 0 10px 25px rgba(0, 0, 0, 0.4);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: 1rem;
}

h1 {
  font-size: 3rem;
}

h2 {
  font-size: 2.5rem;
}

h3 {
  font-size: 2rem;
}

h4 {
  font-size: 1.5rem;
}

p {
  margin-bottom: 1rem;
  color: var(--text-secondary);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 500;
  text-decoration: none;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

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

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

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

.btn-secondary:hover {
  background: var(--primary-color);
  color: white;
}

.btn-icon {
  background: rgba(255, 255, 255, 0.2);
  border: none;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

.btn-icon:hover {
  background: rgba(255, 255, 255, 0.3);
  transform: scale(1.1);
}

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  transition: all 0.3s ease;
}

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

.navbar.scrolled {
  box-shadow: var(--shadow-medium);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 0;
}

.nav-logo h2 {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin: 0;
}

.nav-menu ul {
  display: flex;
  list-style: none;
  gap: 2rem;
}

.nav-link {
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 500;
  transition: color 0.3s ease;
  position: relative;
}

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

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-primary);
  transition: width 0.3s ease;
}

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

.nav-toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
  gap: 4px;
}

.bar {
  width: 25px;
  height: 3px;
  background: var(--text-primary);
  transition: 0.3s;
  border-radius: 2px;
}

.theme-toggle {
  background: none;
  border: 2px solid var(--border-color);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  cursor: pointer;
  font-size: 1.2rem;
  transition: all 0.3s ease;
}

.theme-toggle:hover {
  border-color: var(--primary-color);
  transform: rotate(180deg);
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="%23e5e7eb" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>') center/50px 50px;
  opacity: 0.3;
  z-index: 0;
}

.hero-content {
  flex: 1;
  z-index: 1;
  position: relative;
}

.hero-title {
  font-size: 4rem;
  font-weight: 700;
  margin-bottom: 1rem;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 2.5rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  min-height: 3rem;
}

.typewriter {
  border-right: 3px solid var(--primary-color);
  animation: blink 1s infinite;
}

@keyframes blink {

  0%,
  50% {
    opacity: 1;
  }

  51%,
  100% {
    opacity: 0;
  }
}

.hero-description {
  font-size: 1.2rem;
  margin-bottom: 2rem;
  max-width: 600px;
}

.hero-buttons {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.hero-image {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.floating-elements {
  position: relative;
  width: 300px;
  height: 300px;
}

.float-item {
  position: absolute;
  width: 60px;
  height: 60px;
  background: var(--gradient-accent);
  border-radius: 50%;
  opacity: 0.7;
  animation: float 6s ease-in-out infinite;
}

.float-item:nth-child(1) {
  top: 20%;
  left: 20%;
  animation-delay: 0s;
}

.float-item:nth-child(2) {
  top: 60%;
  right: 20%;
  animation-delay: 2s;
}

.float-item:nth-child(3) {
  bottom: 20%;
  left: 50%;
  animation-delay: 4s;
}

@keyframes float {

  0%,
  100% {
    transform: translateY(0px) rotate(0deg);
  }

  50% {
    transform: translateY(-20px) rotate(180deg);
  }
}

/* Page Hero */
.page-hero {
  padding: 8rem 0 4rem;
  background: var(--gradient-primary);
  text-align: center;
  color: white;
  position: relative;
  overflow: hidden;
}

.page-hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="1" fill="white" opacity="0.1"/></svg>') center/20px 20px;
  z-index: 0;
}

.page-title {
  font-size: 3.5rem;
  margin-bottom: 1rem;
  position: relative;
  z-index: 1;
}

.page-subtitle {
  font-size: 1.2rem;
  opacity: 0.9;
  position: relative;
  z-index: 1;
}

/* Sections */
section {
  padding: 5rem 0;
}

.section-title {
  text-align: center;
  margin-bottom: 3rem;
  font-size: 2.5rem;
  position: relative;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 4px;
  background: var(--gradient-primary);
  border-radius: 2px;
}

/* Features Section */
.features {
  background: var(--bg-secondary);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.feature-card {
  background: var(--bg-primary);
  padding: 2rem;
  border-radius: 12px;
  text-align: center;
  box-shadow: var(--shadow-light);
  transition: all 0.3s ease;
  border: 1px solid var(--border-color);
}

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

.feature-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
  display: block;
}

.feature-card h3 {
  color: var(--text-primary);
  margin-bottom: 1rem;
}

/* Stats Section */
.stats {
  background: var(--gradient-primary);
  color: white;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2rem;
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: 3rem;
  font-weight: 700;
  display: block;
  margin-bottom: 0.5rem;
}

.stat-label {
  font-size: 1.1rem;
  opacity: 0.9;
}

/* Skills Section */
.skills {
  background: var(--bg-secondary);
}

.skills-grid {
  display: grid;
  gap: 1.5rem;
  max-width: 800px;
  margin: 0 auto;
}

.skill-item {
  background: var(--bg-primary);
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: var(--shadow-light);
}

.skill-info {
  display: flex;
  justify-content: space-between;
  margin-bottom: 0.5rem;
}

.skill-name {
  font-weight: 600;
}

.skill-percentage {
  color: var(--primary-color);
  font-weight: 600;
}

.skill-bar {
  height: 8px;
  background: var(--bg-tertiary);
  border-radius: 4px;
  overflow: hidden;
}

.skill-progress {
  height: 100%;
  background: var(--gradient-primary);
  border-radius: 4px;
  width: 0%;
  transition: width 2s ease;
}

/* Projects Section */
.projects-filter {
  background: var(--bg-secondary);
  padding: 2rem 0;
}

.filter-buttons {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 8px 20px;
  border: 2px solid var(--border-color);
  background: var(--bg-primary);
  color: var(--text-primary);
  border-radius: 25px;
  cursor: pointer;
  transition: all 0.3s ease;
  font-weight: 500;
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
}

.projects-gallery {
  background: var(--bg-secondary);
  padding-top: 0;
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 2rem;
}

.project-card {
  background: var(--bg-primary);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-light);
  transition: all 0.3s ease;
  border: 1px solid var(--border-color);
}

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

.project-image {
  position: relative;
  height: 200px;
  overflow: hidden;
}

.image-placeholder {
  width: 100%;
  height: 100%;
  background: var(--gradient-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.2rem;
  font-weight: 600;
}

.project-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.project-card:hover .project-overlay {
  opacity: 1;
}

.project-buttons {
  display: flex;
  gap: 1rem;
}

.project-info {
  padding: 1.5rem;
}

.project-info h3 {
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.project-tags {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.tag {
  background: var(--bg-secondary);
  color: var(--text-secondary);
  padding: 4px 12px;
  border-radius: 15px;
  font-size: 0.85rem;
  font-weight: 500;
}

/* Contact Section */
.contact-content {
  background: var(--bg-secondary);
}

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: start;
}

.contact-info h2,
.contact-form-container h2 {
  color: var(--text-primary);
  margin-bottom: 1.5rem;
}

.contact-description {
  margin-bottom: 2rem;
}

.contact-items {
  margin-bottom: 2rem;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding: 1rem;
  background: var(--bg-primary);
  border-radius: 8px;
  box-shadow: var(--shadow-light);
}

.contact-icon {
  font-size: 1.5rem;
  background: var(--gradient-primary);
  padding: 8px;
  border-radius: 8px;
  color: white;
}

.contact-details h3 {
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  font-size: 1.1rem;
}

.contact-details p {
  margin: 0;
  color: var(--text-secondary);
}

.social-links {
  background: var(--bg-primary);
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: var(--shadow-light);
}

.social-icons {
  display: flex;
  gap: 1rem;
  margin-top: 1rem;
}

.social-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--gradient-primary);
  color: white;
  border-radius: 50%;
  text-decoration: none;
  transition: all 0.3s ease;
}

.social-icon:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-medium);
}

/* Contact Form */
.contact-form-container {
  background: var(--bg-primary);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: var(--shadow-light);
}

.contact-form {
  display: grid;
  gap: 1.5rem;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-group {
  display: flex;
  flex-direction: column;
}

.form-group label {
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
  padding: 12px;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color 0.3s ease;
}

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

.checkbox-group {
  flex-direction: row;
  align-items: center;
  gap: 0.5rem;
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.9rem;
}

.checkbox-label input[type="checkbox"] {
  width: auto;
  margin: 0;
}

.btn-submit {
  width: 100%;
  position: relative;
  overflow: hidden;
}

.btn-loading {
  display: none;
}

.btn-submit.loading .btn-text {
  display: none;
}

.btn-submit.loading .btn-loading {
  display: block;
}

/* Footer */
.footer {
  background: var(--bg-tertiary);
  padding: 3rem 0 1rem;
  border-top: 1px solid var(--border-color);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-section h3,
.footer-section h4 {
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-section p {
  color: var(--text-secondary);
}

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

.footer-section ul li {
  margin-bottom: 0.5rem;
}

.footer-section ul li a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.3s ease;
}

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

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

/* Scroll to Top Button */
.scroll-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--gradient-primary);
  color: white;
  border: none;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  cursor: pointer;
  box-shadow: var(--shadow-medium);
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  z-index: 1000;
}

.scroll-top.visible {
  opacity: 1;
  visibility: visible;
}

.scroll-top:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-heavy);
}

/* About Page Specific */
.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}

.about-highlights {
  display: flex;
  gap: 2rem;
  margin-top: 2rem;
}

.highlight-item {
  text-align: center;
}

.highlight-number {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary-color);
}

.highlight-text {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.values-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.value-card {
  background: var(--bg-primary);
  padding: 2rem;
  border-radius: 12px;
  text-align: center;
  box-shadow: var(--shadow-light);
  transition: all 0.3s ease;
  border: 1px solid var(--border-color);
}

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

.value-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  display: block;
}

.timeline-container {
  position: relative;
  max-width: 800px;
  margin: 0 auto;
}

.timeline-container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 2px;
  height: 100%;
  background: var(--gradient-primary);
}

.timeline-item {
  display: flex;
  align-items: center;
  margin-bottom: 3rem;
  position: relative;
}

.timeline-item:nth-child(odd) {
  flex-direction: row-reverse;
}

.timeline-year {
  background: var(--gradient-primary);
  color: white;
  padding: 1rem 1.5rem;
  border-radius: 8px;
  font-weight: 700;
  margin: 0 2rem;
  position: relative;
  z-index: 1;
}

.timeline-content {
  background: var(--bg-primary);
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: var(--shadow-light);
  flex: 1;
  border: 1px solid var(--border-color);
}

/* Map and FAQ */
.map-container {
  background: var(--bg-primary);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-light);
  height: 300px;
}

.map-placeholder {
  width: 100%;
  height: 100%;
  background: var(--gradient-accent);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: white;
  text-align: center;
}

.map-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.faq-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.faq-item {
  background: var(--bg-primary);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: var(--shadow-light);
  border: 1px solid var(--border-color);
}

.faq-item h3 {
  color: var(--primary-color);
  margin-bottom: 1rem;
}

/* Testimonials */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.testimonial-card {
  background: var(--bg-primary);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: var(--shadow-light);
  border: 1px solid var(--border-color);
}

.testimonial-content {
  margin-bottom: 1.5rem;
}

.testimonial-content p {
  font-style: italic;
  color: var(--text-secondary);
}

.testimonial-author {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.author-avatar {
  width: 50px;
  height: 50px;
  background: var(--gradient-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.2rem;
}

.author-info h4 {
  color: var(--text-primary);
  margin: 0;
  font-size: 1rem;
}

.author-info span {
  color: var(--text-light);
  font-size: 0.9rem;
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in-up {
  animation: fadeInUp 0.6s ease forwards;
}

/* Project Filter Animation */
.project-card.hidden {
  opacity: 0;
  transform: scale(0.8);
  transition: all 0.3s ease;
}

.project-card.visible {
  opacity: 1;
  transform: scale(1);
  transition: all 0.3s ease;
}

/* Form Result Messages */
.form-result {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: 8px;
  display: none;
}

.form-result.success {
  background: rgba(34, 197, 94, 0.1);
  color: #059669;
  border: 1px solid rgba(34, 197, 94, 0.2);
  display: block;
}

.form-result.error {
  background: rgba(239, 68, 68, 0.1);
  color: #dc2626;
  border: 1px solid rgba(239, 68, 68, 0.2);
  display: block;
}