/* Portfolio Website — PR 1: CSS Foundation + Core Sections */

/* Phase 1.1: Custom Properties */
:root {
  --color-bg: #121212;
  --color-bg-secondary: #1E1E1E;
  --color-bg-card: #2A2A2A;
  --color-text: #E0E0E0;
  --color-text-secondary: #A0A0A0;
  --color-accent: #00D4FF;
  --color-accent-hover: #00B8DB;
  --color-border: #333333;
  --color-white: #FFFFFF;
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'Fira Code', 'Consolas', monospace;
  --space-1: 0.25rem; --space-2: 0.5rem; --space-3: 0.75rem;
  --space-4: 1rem; --space-6: 1.5rem; --space-8: 2rem;
  --space-12: 3rem; --space-16: 4rem; --space-20: 5rem;
  --container-max: 1200px;
  --border-radius: 8px;
  --transition-default: 0.3s ease;
}

/* Phase 1.2: Base Reset */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
  font-family: var(--font-sans);
  font-size: clamp(1rem, 1.5vw, 1.125rem);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
}
h1, h2, h3 { line-height: 1.2; font-weight: 600; }
h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.25rem); }
h3 { font-size: clamp(1.125rem, 2vw, 1.5rem); }
a { color: var(--color-accent); text-decoration: none; transition: color var(--transition-default); }
a:hover { color: var(--color-accent-hover); }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }
.container { max-width: var(--container-max); margin: 0 auto; padding: 0 var(--space-4); }
.section { padding: var(--space-16) 0; scroll-margin-top: 80px; }
.section-title { text-align: center; margin-bottom: var(--space-12); }

/* Phase 1.3: Navigation */
.navbar {
  position: sticky; top: 0; z-index: 100;
  background-color: rgba(18, 18, 18, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-4) 0;
}
.navbar .container { display: flex; align-items: center; justify-content: space-between; }
.nav-logo { font-family: var(--font-mono); font-size: 1.25rem; font-weight: 500; color: var(--color-accent); }
.nav-toggle {
  display: flex; flex-direction: column; gap: 5px;
  background: none; border: none; cursor: pointer; padding: var(--space-2);
}
.hamburger {
  display: block; width: 24px; height: 2px;
  background-color: var(--color-text); border-radius: 2px;
  transition: var(--transition-default); position: relative;
}
.hamburger::before, .hamburger::after {
  content: ''; position: absolute; width: 24px; height: 2px;
  background-color: var(--color-text); border-radius: 2px; transition: var(--transition-default);
}
.hamburger::before { top: -7px; }
.hamburger::after { top: 7px; }
.nav-menu {
  display: none; flex-direction: column; gap: var(--space-4);
  position: absolute; top: 100%; left: 0; right: 0;
  background-color: var(--color-bg-secondary); padding: var(--space-6);
  border-bottom: 1px solid var(--color-border);
}
.nav-menu.active { display: flex; }
.nav-link { color: var(--color-text-secondary); font-weight: 500; transition: color var(--transition-default); }
.nav-link:hover { color: var(--color-accent); }

/* Phase 2.1: Hero Section */
.hero { min-height: 100vh; display: flex; align-items: center; padding: var(--space-20) 0; }
.hero-content { display: flex; flex-direction: column; align-items: flex-start; gap: var(--space-4); }
.hero-greeting { font-family: var(--font-mono); font-size: 1rem; color: var(--color-accent); }
.hero-name { font-size: clamp(2.5rem, 8vw, 5rem); font-weight: 700; color: var(--color-white); line-height: 1.1; display: flex; align-items: center; gap: var(--space-6); flex-wrap: wrap; }
.hero-avatar {
  width: clamp(80px, 15vw, 140px);
  height: clamp(80px, 15vw, 140px);
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--color-accent);
}
.hero-title { font-size: clamp(1.25rem, 4vw, 2rem); color: var(--color-text-secondary); }
.hero-title .accent { color: var(--color-accent); }
.hero-description { max-width: 600px; color: var(--color-text-secondary); font-size: 1.125rem; }
.hero-cta { display: flex; gap: var(--space-4); margin-top: var(--space-4); flex-wrap: wrap; }
.btn {
  display: inline-block; padding: var(--space-3) var(--space-6);
  border-radius: var(--border-radius); font-weight: 500; font-size: 1rem;
  cursor: pointer; transition: all var(--transition-default);
  border: 2px solid transparent; text-align: center;
}
.btn-primary { background-color: var(--color-accent); color: var(--color-bg); border-color: var(--color-accent); }
.btn-primary:hover { background-color: var(--color-accent-hover); border-color: var(--color-accent-hover); color: var(--color-bg); }
.btn-secondary { background-color: transparent; color: var(--color-accent); border-color: var(--color-accent); }
.btn-secondary:hover { background-color: var(--color-accent); color: var(--color-bg); }
.hero-social { display: flex; gap: var(--space-4); margin-top: var(--space-4); }
.hero-social a { color: var(--color-text-secondary); transition: color var(--transition-default); display: flex; align-items: center; }
.hero-social a:hover { color: var(--color-accent); }

/* Phase 2.2: About Section */
.about-content { display: grid; grid-template-columns: 1fr; gap: var(--space-8); }
.about-text { display: flex; flex-direction: column; gap: var(--space-4); }
.about-highlight {
  font-size: 1.25rem; font-weight: 500; color: var(--color-accent);
  border-left: 3px solid var(--color-accent); padding-left: var(--space-4);
}
.about-stats { display: flex; gap: var(--space-6); flex-wrap: wrap; }
.stat-card {
  display: flex; flex-direction: column; align-items: center; gap: var(--space-2);
  padding: var(--space-6); background-color: var(--color-bg-secondary);
  border-radius: var(--border-radius); border: 1px solid var(--color-border);
  min-width: 140px; flex: 1;
}
.stat-number { font-size: 2rem; font-weight: 700; color: var(--color-accent); }
.stat-label { font-size: 0.875rem; color: var(--color-text-secondary); text-align: center; }

/* Phase 2.3: Featured Projects */
.featured-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: var(--space-6); }
.featured-card {
  background-color: var(--color-bg-secondary); border-radius: var(--border-radius);
  border: 1px solid var(--color-border); overflow: hidden;
  transition: transform var(--transition-default);
}
.featured-card:hover { transform: translateY(-4px); }
.featured-card-image { width: 100%; height: 200px; overflow: hidden; }
.featured-card-image img { width: 100%; height: 100%; object-fit: cover; }
.featured-card-content { padding: var(--space-6); display: flex; flex-direction: column; gap: var(--space-3); }
.featured-card-header { display: flex; align-items: center; justify-content: space-between; }
.featured-card-header h3 { color: var(--color-white); }
.btn-icon {
  display: flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: var(--border-radius);
  color: var(--color-text-secondary); transition: color var(--transition-default);
}
.btn-icon:hover { color: var(--color-accent); }
.featured-card-description { color: var(--color-text-secondary); font-size: 0.9375rem; }
.featured-card-stack { display: flex; flex-wrap: wrap; gap: var(--space-2); margin-top: auto; }
.tag {
  font-family: var(--font-mono); font-size: 0.75rem;
  padding: var(--space-1) var(--space-3); background-color: var(--color-bg-card);
  color: var(--color-text-secondary); border-radius: 4px;
  border: 1px solid var(--color-border);
}

/* Phase 2.4: Filter Buttons */
.filter-buttons { display: flex; flex-wrap: wrap; gap: var(--space-3); justify-content: center; margin-bottom: var(--space-8); }
.filter-btn {
  padding: var(--space-2) var(--space-4); border-radius: 9999px;
  border: 1px solid var(--color-border); background-color: transparent;
  color: var(--color-text-secondary); font-family: var(--font-sans);
  font-size: 0.875rem; font-weight: 500; cursor: pointer;
  transition: all var(--transition-default);
}
.filter-btn:hover { border-color: var(--color-accent); color: var(--color-accent); }
.filter-btn.active { background-color: var(--color-accent); border-color: var(--color-accent); color: var(--color-bg); }

/* Phase 2.5: Skills Section */
.skills-categories { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: var(--space-6); }
.skill-category {
  padding: var(--space-6); background-color: var(--color-bg-secondary);
  border-radius: var(--border-radius); border: 1px solid var(--color-border);
}
.skill-category-title {
  display: flex; align-items: center; gap: var(--space-2);
  font-size: 1.125rem; color: var(--color-white); margin-bottom: var(--space-4);
}
.skill-category-title svg { color: var(--color-accent); flex-shrink: 0; }
.skill-tags { display: flex; flex-wrap: wrap; gap: var(--space-2); }
.skill-tag {
  font-family: var(--font-mono); font-size: 0.8125rem;
  padding: var(--space-1) var(--space-3); background-color: var(--color-bg-card);
  color: var(--color-text-secondary); border-radius: 9999px;
  border: 1px solid var(--color-border); transition: all var(--transition-default);
}
.skill-tag:hover { border-color: var(--color-accent); color: var(--color-accent); }

/* Phase 3: Portfolio Projects Grid */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-6);
}
.project-card {
  background-color: var(--color-bg-secondary);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: transform var(--transition-default);
}
.project-card:hover { transform: translateY(-4px); }
.project-card-image { height: 200px; overflow: hidden; }
.project-card-image img { width: 100%; height: 100%; object-fit: cover; }
.project-card-image--logo img { object-fit: contain; padding: var(--space-4); }
.project-card-content {
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.project-card-content h3 { color: var(--color-white); }
.project-card-tags { display: flex; flex-wrap: wrap; gap: var(--space-2); }
.project-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: auto;
}
.project-context { color: var(--color-text-secondary); font-size: 0.875rem; }
.btn-small {
  display: inline-block;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--border-radius);
  font-weight: 500;
  font-size: 0.875rem;
  cursor: pointer;
  transition: all var(--transition-default);
  border: 2px solid transparent;
  text-align: center;
  background-color: var(--color-accent);
  color: var(--color-bg);
  border-color: var(--color-accent);
}
.btn-small:hover {
  background-color: var(--color-accent-hover);
  border-color: var(--color-accent-hover);
  color: var(--color-bg);
}
.project-card.hidden { display: none; }

/* Phase 4: GitHub Section — Carousel */
.carousel-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-4);
}
.carousel-track {
  display: flex;
  gap: var(--space-6);
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-behavior: smooth;
  padding: var(--space-4) 0;
  -ms-overflow-style: none;
  scrollbar-width: none;
  flex-wrap: nowrap;
  min-width: 0;
}
.carousel-track::-webkit-scrollbar { display: none; }
.carousel-btn {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 1px solid var(--color-border);
  background-color: var(--color-bg-secondary);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-default);
  z-index: 2;
}
.carousel-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}
.carousel-dots {
  display: flex;
  justify-content: center;
  gap: var(--space-2);
  margin-top: var(--space-4);
}
.carousel-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: none;
  background-color: var(--color-border);
  cursor: pointer;
  transition: all var(--transition-default);
}
.carousel-dot.active {
  background-color: var(--color-accent);
  width: 24px;
  border-radius: 4px;
}
.carousel-counter {
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.8125rem;
  margin-top: var(--space-2);
}
.github-repo-card {
  flex: 0 0 320px;
  scroll-snap-align: start;
  background-color: var(--color-bg-secondary);
  border-radius: var(--border-radius);
  padding: var(--space-6);
  border: 1px solid var(--color-border);
  transition: transform var(--transition-default);
  text-decoration: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.github-repo-card:hover { transform: translateY(-4px); }
.github-repo-card h3 { color: var(--color-white); margin-bottom: var(--space-2); }
.repo-language {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}
.language-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
}
.repo-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
}
.repo-stars {
  color: var(--color-accent);
  font-size: 0.875rem;
}
.repo-description {
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.loading-spinner {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  padding: var(--space-12) 0;
  color: var(--color-text-secondary);
  width: 100%;
}
.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Phase 5: Contact Section */
.contact-content {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}
.contact-text {
  margin-bottom: var(--space-8);
  color: var(--color-text-secondary);
}
.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  justify-content: center;
}
.contact-link {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-6);
  background-color: var(--color-bg-secondary);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  transition: all var(--transition-default);
}
.contact-link:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}
.contact-link span { font-size: 0.875rem; }

/* Phase 5b: Footer */
.footer {
  background-color: var(--color-bg-secondary);
  padding: var(--space-6) 0;
  border-top: 1px solid var(--color-border);
}
.footer-text {
  color: var(--color-text-secondary);
  text-align: center;
  font-size: 0.875rem;
}

/* Phase 6: Responsive Media Queries */
@media (max-width: 767px) {
  .carousel-btn { width: 32px; height: 32px; }
  .carousel-btn svg { width: 16px; height: 16px; }
  .github-repo-card { flex: 0 0 280px; }
}
@media (min-width: 768px) {
  .nav-menu {
    display: flex;
    position: static;
    background: transparent;
    border: none;
    flex-direction: row;
    padding: 0;
  }
  .nav-toggle { display: none; }
  .about-content { grid-template-columns: 2fr 1fr; }
  .featured-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 1024px) {
  .featured-grid { grid-template-columns: repeat(3, 1fr); }
  .hero-content {
    align-items: center;
    text-align: center;
  }
  .hero-description { margin: 0 auto; }
}

/* Phase 7: Animations & Accessibility */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}
.hidden { display: none !important; }