:root {
  --primary: #2563eb;
  --secondary: #1e40af;
  --accent: #3b82f6;
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --text-primary: #1e293b;
  --text-secondary: #475569;
  --border: #e2e8f0;
  --shadow: rgba(37, 99, 235, 0.1);
}

[data-theme="dark"] {
  --primary: #3b82f6;
  --secondary: #2563eb;
  --accent: #60a5fa;
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --border: #334155;
  --shadow: rgba(59, 130, 246, 0.2);
}

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

body {
  font-family: "Courier New", monospace;
  background: var(--bg-primary);
  color: var(--text-primary);
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Pixel Grid Background */
body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 20px 20px;
  pointer-events: none;
  z-index: 0;
  opacity: 0.5;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  position: relative;
  z-index: 1;
}

/* Header/Navigation */
header {
  padding: 20px 0;
  border-bottom: 2px solid var(--primary);
  background: var(--bg-primary);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 4px 15px var(--shadow);
  transition: all 0.3s ease;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
}

.logo {
  font-size: 24px;
  font-weight: bold;
  color: var(--primary);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 20px;
}

.back-btn {
  padding: 8px 20px;
  border: 2px solid var(--primary);
  background: transparent;
  color: var(--primary);
  text-decoration: none;
  font-size: 14px;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.3s;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.back-btn:hover {
  background: var(--primary);
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 5px 15px var(--shadow);
}

/* Theme Toggle Switch */
.theme-switch-wrapper {
  display: flex;
  align-items: center;
}

.theme-switch {
  position: relative;
  display: inline-block;
  width: 60px;
  height: 30px;
}

.theme-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--border);
  transition: 0.4s;
  border: 2px solid var(--primary);
}

.slider:before {
  position: absolute;
  content: "";
  height: 20px;
  width: 20px;
  left: 3px;
  bottom: 3px;
  background-color: var(--primary);
  transition: 0.4s;
}

input:checked + .slider {
  background-color: var(--bg-secondary);
}

input:checked + .slider:before {
  transform: translateX(30px);
}

.slider i {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  font-size: 14px;
  transition: 0.4s;
}

.slider .fa-sun {
  left: 6px;
  color: #fbbf24;
}

.slider .fa-moon {
  right: 6px;
  color: var(--text-secondary);
}

input:checked + .slider .fa-sun {
  opacity: 0.3;
}

input:checked + .slider .fa-moon {
  color: #60a5fa;
  opacity: 1;
}

/* Page Header */
.page-header {
  padding: 80px 20px 40px;
  text-align: center;
}

.page-header h1 {
  font-size: clamp(36px, 6vw, 56px);
  margin-bottom: 20px;
  color: var(--text-primary);
  letter-spacing: 2px;
}

.page-header p {
  font-size: clamp(16px, 2vw, 20px);
  color: var(--text-secondary);
  max-width: 700px;
  margin: 0 auto;
  line-height: 1.8;
}

/* Filter Buttons */
.filter-section {
  padding: 40px 20px;
  text-align: center;
}

.filter-buttons {
  display: flex;
  justify-content: center;
  gap: 15px;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 10px 25px;
  border: 2px solid var(--border);
  background: transparent;
  color: var(--text-primary);
  font-family: "Courier New", monospace;
  font-size: 14px;
  cursor: pointer;
  transition: all 0.3s;
}

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

/* Projects Grid */
.projects-section {
  padding: 40px 20px 80px;
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 30px;
  margin-top: 30px;
}

.project-card {
  border: 2px solid var(--border);
  padding: 0;
  background: var(--bg-secondary);
  transition: all 0.3s;
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  opacity: 0;
  animation: fadeIn 0.5s forwards;
}

@keyframes fadeIn {
  to {
    opacity: 1;
  }
}

.project-card:nth-child(1) {
  animation-delay: 0.1s;
}
.project-card:nth-child(2) {
  animation-delay: 0.2s;
}
.project-card:nth-child(3) {
  animation-delay: 0.3s;
}
.project-card:nth-child(4) {
  animation-delay: 0.4s;
}
.project-card:nth-child(5) {
  animation-delay: 0.5s;
}
.project-card:nth-child(6) {
  animation-delay: 0.6s;
}
.project-card:nth-child(7) {
  animation-delay: 0.7s;
}
.project-card:nth-child(8) {
  animation-delay: 0.8s;
}
.project-card:nth-child(9) {
  animation-delay: 0.9s;
}

.project-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, transparent, var(--primary), transparent);
  transition: 0.5s;
  z-index: 1;
}

.project-card:hover::before {
  left: 100%;
}

.project-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 40px var(--shadow);
  border-color: var(--primary);
}

.project-image {
  width: 100%;
  height: 200px;
  background: var(--bg-primary);
  border-bottom: 2px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  position: relative;
}

.project-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.3s;
}

.project-card:hover .project-image img {
  transform: scale(1.1);
}

.project-image i {
  font-size: 60px;
  color: var(--primary);
  opacity: 0.3;
}

.project-content {
  padding: 25px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.project-content h3 {
  font-size: 20px;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.project-content p {
  color: var(--text-secondary);
  margin-bottom: 15px;
  line-height: 1.6;
  font-size: 14px;
  flex: 1;
}

.tech-stack {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 15px;
}

.tech-tag {
  padding: 4px 10px;
  border: 1px solid var(--primary);
  font-size: 11px;
  color: var(--primary);
  background: var(--bg-primary);
}

.project-buttons {
  display: flex;
  gap: 8px;
  margin-top: auto;
}

.btn-small {
  padding: 8px 16px;
  font-size: 12px;
  border: 2px solid var(--primary);
  background: transparent;
  color: var(--primary);
  text-decoration: none;
  cursor: pointer;
  transition: all 0.3s;
  flex: 1;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.btn-small::before {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: var(--primary);
  transition: 0.3s;
  z-index: -1;
}

.btn-small:hover::before {
  left: 0;
}

.btn-small:hover {
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 5px 15px var(--shadow);
}

.btn-small i {
  margin-right: 5px;
}

/* Footer */
footer {
  text-align: center;
  padding: 30px 20px;
  border-top: 2px solid var(--primary);
  background: var(--bg-secondary);
}

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

/* Responsive */
@media (max-width: 768px) {
  .projects-grid {
    grid-template-columns: 1fr;
  }

  .filter-buttons {
    gap: 10px;
  }

  .filter-btn {
    padding: 8px 15px;
    font-size: 12px;
  }

  .nav-right {
    width: 100%;
    justify-content: space-between;
  }
}