/* CSS Reset & Variables */
:root {
  /* Light Theme Variables */
  --bg-primary: #fbfbfb;
  --bg-secondary: #f3f4f6;
  --bg-card: #ffffff;
  --text-primary: #111827;
  --text-secondary: #4b5563;
  --text-muted: #9ca3af;
  --border-color: #111827;
  --border-width: 2px;
  
  /* Palette Colors */
  --accent-blue: #3b82f6;
  --accent-green: #10b981;
  --accent-yellow: #f59e0b;
  --accent-purple: #8b5cf6;
  --accent-red: #ef4444;
  
  --primary-accent: #2563eb;
  --primary-accent-light: #dbeafe;
  
  /* Shadow & Transitions */
  --shadow-flat: 4px 4px 0px var(--border-color);
  --shadow-flat-hover: 8px 8px 0px var(--border-color);
  --shadow-flat-sm: 2px 2px 0px var(--border-color);
  --transition-speed: 0.25s;
  --transition-bounce: cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

[data-theme="dark"] {
  /* Dark Theme Variables */
  --bg-primary: #0f1013;
  --bg-secondary: #16181d;
  --bg-card: #1d2027;
  --text-primary: #f9fafb;
  --text-secondary: #d1d5db;
  --text-muted: #6b7280;
  --border-color: #374151;
  --border-width: 2px;
  
  --primary-accent: #60a5fa;
  --primary-accent-light: #1e293b;
  
  --shadow-flat: 4px 4px 0px var(--border-color);
  --shadow-flat-hover: 6px 6px 0px var(--border-color);
  --shadow-flat-sm: 2px 2px 0px var(--border-color);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease;
  line-height: 1.6;
  overflow-x: hidden;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

a {
  color: inherit;
  text-decoration: none;
  transition: all var(--transition-speed) var(--transition-bounce);
}

/* Layout Container */
.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* Header & Navigation */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg-primary);
  border-bottom: var(--border-width) solid var(--border-color);
  transition: border-color var(--transition-speed) ease, background-color var(--transition-speed) ease;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 80px;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo-dot {
  width: 10px;
  height: 10px;
  background-color: var(--primary-accent);
  border-radius: 50%;
  border: 1px solid var(--border-color);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 2.5rem;
  list-style: none;
}

.nav-link {
  font-weight: 600;
  font-size: 0.95rem;
  position: relative;
  padding: 0.25rem 0;
}

.nav-link::after {
  content: '';
  position: absolute;
  width: 100%;
  transform: scaleX(0);
  height: 2px;
  bottom: 0;
  left: 0;
  background-color: var(--primary-accent);
  transform-origin: bottom right;
  transition: transform var(--transition-speed) ease-out;
}

.nav-link:hover::after {
  transform: scaleX(1);
  transform-origin: bottom left;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* Theme Toggle Button */
.theme-toggle-btn {
  background: var(--bg-card);
  border: var(--border-width) solid var(--border-color);
  cursor: pointer;
  width: 44px;
  height: 44px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: var(--text-primary);
  box-shadow: var(--shadow-flat-sm);
  transition: transform 0.1s, box-shadow 0.1s, background-color var(--transition-speed);
}

.theme-toggle-btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: 3px 3px 0px var(--border-color);
}

.theme-toggle-btn:active {
  transform: translate(1px, 1px);
  box-shadow: 1px 1px 0px var(--border-color);
}

/* Neo-Brutalism flat buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 0.95rem;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  border: var(--border-width) solid var(--border-color);
  cursor: pointer;
  transition: transform 0.15s var(--transition-bounce), box-shadow 0.15s var(--transition-bounce);
}

.btn-primary {
  background-color: var(--primary-accent);
  color: #ffffff;
  box-shadow: var(--shadow-flat);
}

.btn-primary:hover {
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow-flat-hover);
}

.btn-primary:active {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0px var(--border-color);
}

.btn-secondary {
  background-color: var(--bg-card);
  color: var(--text-primary);
  box-shadow: var(--shadow-flat);
}

.btn-secondary:hover {
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow-flat-hover);
}

.btn-secondary:active {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0px var(--border-color);
}

/* Sections General */
section {
  padding: 6rem 0;
  border-bottom: var(--border-width) solid var(--border-color);
  background-color: var(--bg-primary);
}

.section-title-wrap {
  margin-bottom: 4rem;
  text-align: center;
}

.section-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  padding: 0.25rem 0.75rem;
  background-color: var(--primary-accent-light);
  color: var(--primary-accent);
  border: var(--border-width) solid var(--border-color);
  border-radius: 50px;
  margin-bottom: 1rem;
}

.section-title {
  font-size: 2.5rem;
}

/* Hero Section */
.hero {
  position: relative;
  overflow: hidden;
  padding: 8rem 0;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 4rem;
  align-items: center;
}

.hero-content {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1.5rem;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  font-weight: 700;
  background-color: #fef08a;
  color: #854d0e;
  border: var(--border-width) solid var(--border-color);
  padding: 0.4rem 1rem;
  border-radius: 50px;
  box-shadow: var(--shadow-flat-sm);
}

[data-theme="dark"] .hero-badge {
  background-color: #451a03;
  color: #fef08a;
}

.hero-badge .ping {
  width: 8px;
  height: 8px;
  background-color: #ca8a04;
  border-radius: 50%;
  animation: ping 1.5s cubic-bezier(0, 0, 0.2, 1) infinite;
}

@keyframes ping {
  75%, 100% {
    transform: scale(2);
    opacity: 0;
  }
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 900;
}

.hero-title span {
  color: var(--primary-accent);
  position: relative;
}

.hero-desc {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 540px;
}

.hero-actions {
  display: flex;
  gap: 1.5rem;
  margin-top: 1rem;
}

/* Interactive Flat Illustration */
.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.visual-canvas {
  width: 100%;
  max-width: 380px;
  aspect-ratio: 1;
  background-color: var(--bg-card);
  border: var(--border-width) solid var(--border-color);
  border-radius: 24px;
  box-shadow: var(--shadow-flat);
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
}

.visual-element {
  position: absolute;
  border: var(--border-width) solid var(--border-color);
  background-color: var(--bg-secondary);
  transition: transform 0.5s var(--transition-bounce), background-color var(--transition-speed);
}

.visual-circle {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  background-color: var(--accent-purple);
  top: 15%;
  left: 15%;
}

.visual-rect {
  width: 120px;
  height: 120px;
  background-color: var(--accent-yellow);
  bottom: 20%;
  right: 15%;
  transform: rotate(15deg);
}

.visual-triangle {
  width: 0;
  height: 0;
  border-left: 60px solid transparent;
  border-right: 60px solid transparent;
  border-bottom: 100px solid var(--accent-green);
  border-top: 0;
  bottom: 40%;
  left: 45%;
  background: transparent !important;
  border-radius: 0;
}

/* Interactive visual effect on hover */
.visual-canvas:hover .visual-circle {
  transform: translate(15px, -15px);
  background-color: var(--accent-red);
}

.visual-canvas:hover .visual-rect {
  transform: rotate(-15deg) translate(-10px, 10px);
  background-color: var(--accent-blue);
}

.visual-canvas:hover .visual-triangle {
  transform: scale(1.1) rotate(10deg);
}

.visual-code-tag {
  position: absolute;
  bottom: 15px;
  left: 15px;
  background-color: var(--bg-primary);
  border: var(--border-width) solid var(--border-color);
  padding: 0.3rem 0.8rem;
  border-radius: 6px;
  font-family: monospace;
  font-size: 0.8rem;
  font-weight: 700;
  box-shadow: var(--shadow-flat-sm);
}

/* Skills Section */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 2rem;
}

.skill-card {
  background-color: var(--bg-card);
  border: var(--border-width) solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  box-shadow: var(--shadow-flat);
  transition: transform 0.2s var(--transition-bounce), box-shadow 0.2s var(--transition-bounce);
}

.skill-card:hover {
  transform: translate(-4px, -4px);
  box-shadow: var(--shadow-flat-hover);
}

.skill-icon {
  width: 56px;
  height: 56px;
  border-radius: 8px;
  border: var(--border-width) solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  background-color: var(--primary-accent-light);
  color: var(--primary-accent);
}

.skill-title {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

.skill-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

/* Projects Section */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2.5rem;
}

.project-card {
  background-color: var(--bg-card);
  border: var(--border-width) solid var(--border-color);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: var(--shadow-flat);
  transition: transform 0.25s var(--transition-bounce), box-shadow 0.25s var(--transition-bounce);
  display: flex;
  flex-direction: column;
}

.project-card:hover {
  transform: translate(-4px, -4px);
  box-shadow: var(--shadow-flat-hover);
}

.project-img-wrap {
  height: 200px;
  background-color: var(--bg-secondary);
  border-bottom: var(--border-width) solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.project-placeholder-icon {
  font-size: 4rem;
  opacity: 0.9;
  transition: transform 0.3s var(--transition-bounce);
}

.project-card:hover .project-placeholder-icon {
  transform: scale(1.15) rotate(5deg);
}

.project-tags {
  position: absolute;
  bottom: 12px;
  left: 12px;
  display: flex;
  gap: 0.5rem;
}

.project-tag {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.6rem;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 4px;
}

.project-content {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  flex-grow: 1;
}

.project-title {
  font-size: 1.35rem;
}

.project-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  flex-grow: 1;
}

.project-links {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 0.5rem;
}

.project-link-btn {
  font-size: 0.85rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.25rem;
  border-bottom: 1.5px solid transparent;
}

.project-link-btn:hover {
  color: var(--primary-accent);
  border-bottom-color: var(--primary-accent);
}

/* Services / Pricing Area */
.services-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.service-card {
  background-color: var(--bg-card);
  border: var(--border-width) solid var(--border-color);
  border-radius: 16px;
  padding: 2.5rem 2rem;
  box-shadow: var(--shadow-flat);
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

.service-badge {
  position: absolute;
  top: -15px;
  right: 20px;
  background-color: var(--accent-green);
  color: #ffffff;
  border: var(--border-width) solid var(--border-color);
  padding: 0.25rem 0.75rem;
  border-radius: 50px;
  font-size: 0.8rem;
  font-weight: 800;
}

.service-price {
  font-size: 2.25rem;
  font-weight: 850;
  margin-top: 0.5rem;
}

.service-price span {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.service-features {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin: 1rem 0;
  flex-grow: 1;
}

.service-features li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.service-features li i {
  color: var(--accent-green);
}

/* Footer & Contact Section */
footer {
  background-color: var(--bg-secondary);
  padding: 6rem 0 3rem 0;
  border-top: var(--border-width) solid var(--border-color);
  transition: background-color var(--transition-speed) ease;
}

.footer-container {
  display: flex;
  flex-direction: column;
  gap: 4rem;
}

.contact-card {
  background-color: var(--bg-card);
  border: var(--border-width) solid var(--border-color);
  border-radius: 24px;
  padding: 4rem 2rem;
  text-align: center;
  box-shadow: var(--shadow-flat);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
  position: relative;
}

.contact-title {
  font-size: 2.5rem;
  font-weight: 900;
}

.contact-desc {
  max-width: 500px;
  color: var(--text-secondary);
  font-size: 1.1rem;
}

.email-box {
  display: flex;
  align-items: center;
  background-color: var(--bg-primary);
  border: var(--border-width) solid var(--border-color);
  border-radius: 12px;
  padding: 0.5rem 0.5rem 0.5rem 1.5rem;
  width: 100%;
  max-width: 460px;
  margin-top: 1rem;
  box-shadow: var(--shadow-flat-sm);
  transition: transform 0.15s var(--transition-bounce), box-shadow 0.15s var(--transition-bounce);
}

.email-box:hover {
  transform: translate(-1px, -1px);
  box-shadow: 4px 4px 0px var(--border-color);
}

.email-text {
  font-family: monospace;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  flex-grow: 1;
  text-align: left;
  user-select: all;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.copy-btn {
  background-color: var(--primary-accent);
  color: #ffffff;
  border: var(--border-width) solid var(--border-color);
  border-radius: 8px;
  padding: 0.6rem 1.2rem;
  font-weight: 700;
  font-size: 0.9rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: transform 0.1s, background-color var(--transition-speed);
}

.copy-btn:hover {
  background-color: var(--accent-blue);
}

.copy-btn:active {
  transform: scale(0.95);
}

/* Toast Copy Bubble Alert */
.toast-bubble {
  position: absolute;
  top: 15px;
  left: 50%;
  transform: translateX(-50%) translateY(-20px);
  background-color: var(--border-color);
  color: var(--bg-primary);
  padding: 0.5rem 1rem;
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 700;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease, transform 0.3s var(--transition-bounce);
}

.toast-bubble.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 1rem;
}

.social-icon {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: var(--border-width) solid var(--border-color);
  background-color: var(--bg-card);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  box-shadow: var(--shadow-flat-sm);
}

.social-icon:hover {
  transform: translateY(-4px) rotate(8deg);
  box-shadow: 4px 4px 0px var(--border-color);
  color: var(--primary-accent);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: var(--border-width) solid var(--border-color);
  padding-top: 2rem;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.footer-beian a {
  color: inherit;
}

.footer-beian a:hover {
  color: var(--primary-accent);
  text-decoration: underline;
}

/* Menu Toggle for Mobile */
.mobile-menu-btn {
  display: none;
  background: var(--bg-card);
  border: var(--border-width) solid var(--border-color);
  width: 44px;
  height: 44px;
  border-radius: 8px;
  cursor: pointer;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  box-shadow: var(--shadow-flat-sm);
}

/* Responsive Design */
@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  
  .hero-visual {
    order: -1;
  }
  
  .hero-title {
    font-size: 2.8rem;
  }
  
  .section-title {
    font-size: 2rem;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    display: none; /* Can toggle via Javascript classes */
    flex-direction: column;
    position: absolute;
    top: 80px;
    left: 0;
    width: 100%;
    background-color: var(--bg-primary);
    border-bottom: var(--border-width) solid var(--border-color);
    padding: 2rem;
    gap: 1.5rem;
    align-items: flex-start;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  }
  
  .nav-menu.active {
    display: flex;
  }
  
  .mobile-menu-btn {
    display: flex;
  }
  
  .footer-bottom {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .hero-actions {
    flex-direction: column;
    width: 100%;
  }
  
  .btn {
    width: 100%;
  }
  
  .email-box {
    flex-direction: column;
    padding: 1rem;
    gap: 1rem;
  }
  
  .email-text {
    text-align: center;
    width: 100%;
  }
  
  .copy-btn {
    width: 100%;
    justify-content: center;
  }
  
  .contact-title {
    font-size: 2rem;
  }
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeIn 0.6s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

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

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }