/* ================================================
   Design System — Konstantinos Bourantas
   ================================================ */
:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface-2: #21262d;
  --border: #30363d;
  --accent: #a78bfa;
  --accent-dim: rgba(167, 139, 250, 0.1);
  --text-primary: #e6edf3;
  --text-secondary: #7d8590;
  --text-muted: #484f58;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
  --transition: 0.2s ease;
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --radius: 10px;
}

/* ================================================
   Reset & Base
   ================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  scrollbar-width: thin;
  scrollbar-color: var(--border) var(--bg);
}

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

body {
  background: var(--bg);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { display: block; max-width: 100%; }

/* ================================================
   Navigation
   ================================================ */
#navbar {
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 100;
  padding: 1.25rem 0;
  transition: padding var(--transition), background var(--transition), border-color var(--transition);
  border-bottom: 1px solid transparent;
}

#navbar.scrolled {
  background: rgba(13, 17, 23, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom-color: var(--border);
  padding: 0.875rem 0;
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--accent);
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  transition: color var(--transition);
}

.nav-links a:hover { color: var(--text-primary); }

.btn-nav {
  color: var(--accent) !important;
  border: 1px solid var(--accent);
  padding: 0.5rem 1.125rem !important;
  border-radius: 6px;
  transition: background var(--transition) !important;
}

.btn-nav:hover { background: var(--accent-dim) !important; }

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition);
}

.nav-links.open {
  display: flex !important;
  flex-direction: column;
  position: fixed;
  top: 0; right: 0; bottom: 0;
  width: 65%;
  max-width: 280px;
  background: var(--surface);
  border-left: 1px solid var(--border);
  padding: 5rem 2rem 2rem;
  gap: 1.75rem;
  z-index: 99;
  box-shadow: -8px 0 32px rgba(0, 0, 0, 0.4);
}

/* ================================================
   Hero
   ================================================ */
#hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 0 2rem;
  max-width: 1100px;
  margin: 0 auto;
  position: relative;
}

.hero-greeting {
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 1rem;
  margin-bottom: 1rem;
  opacity: 0;
  animation: fadeUp 0.6s 0.2s forwards;
}

.hero-name {
  font-size: clamp(2.5rem, 6vw, 5rem);
  font-weight: 700;
  letter-spacing: -2px;
  line-height: 1.05;
  margin-bottom: 0.875rem;
  opacity: 0;
  animation: fadeUp 0.6s 0.35s forwards;
}

.hero-role {
  font-size: clamp(1.25rem, 3vw, 2rem);
  font-weight: 300;
  color: var(--text-secondary);
  margin-bottom: 1.75rem;
  min-height: 3rem;
  opacity: 0;
  animation: fadeUp 0.6s 0.5s forwards;
}

#typed-text { color: var(--accent); font-weight: 500; }
.typed-cursor { color: var(--accent); }

.hero-tagline {
  max-width: 500px;
  color: var(--text-secondary);
  font-size: 1.0625rem;
  margin-bottom: 2.5rem;
  line-height: 1.7;
  opacity: 0;
  animation: fadeUp 0.6s 0.65s forwards;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  opacity: 0;
  animation: fadeUp 0.6s 0.8s forwards;
}

.hero-scroll {
  position: absolute;
  bottom: 2.5rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--text-muted);
  font-size: 0.6875rem;
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  opacity: 0;
  animation: fadeIn 1s 1.5s forwards;
}

.scroll-line {
  width: 40px;
  height: 1px;
  background: var(--text-muted);
  animation: scrollPulse 2s 2s infinite;
}

/* ================================================
   Buttons
   ================================================ */
.btn-primary {
  display: inline-block;
  background: var(--accent);
  color: #0d1117;
  padding: 0.75rem 1.75rem;
  border-radius: 6px;
  font-weight: 600;
  font-size: 0.9375rem;
  transition: opacity var(--transition), transform var(--transition);
}

.btn-primary:hover { opacity: 0.85; transform: translateY(-1px); }

.btn-secondary {
  display: inline-block;
  color: var(--text-primary);
  border: 1px solid var(--border);
  padding: 0.75rem 1.75rem;
  border-radius: 6px;
  font-weight: 500;
  font-size: 0.9375rem;
  background: var(--surface);
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
}

.btn-secondary:hover {
  border-color: var(--accent);
  background: var(--accent-dim);
  transform: translateY(-1px);
}

/* ================================================
   Sections
   ================================================ */
section { padding: 6rem 0; }

.section-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
}

.section-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 3rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  white-space: nowrap;
}

.section-title::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
  max-width: 320px;
  min-width: 40px;
}

.title-num {
  font-family: var(--font-mono);
  font-size: 1rem;
  color: var(--accent);
  font-weight: 400;
}

/* ================================================
   About
   ================================================ */
#about { background: var(--bg); }

.about-grid {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 4rem;
  align-items: start;
}

.about-text p {
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  font-size: 1rem;
  line-height: 1.8;
}

.about-text strong { color: var(--text-primary); font-weight: 600; }

.about-interests {
  margin-top: 1.5rem;
}

.about-interests h4 {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

.about-interests ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.about-interests ul li {
  font-size: 0.9rem;
  color: var(--text-secondary);
  padding-left: 1.25rem;
  position: relative;
}

.about-interests ul li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-size: 0.75rem;
  top: 0.1em;
}

.about-links {
  display: flex;
  gap: 1.5rem;
  margin-top: 2rem;
  flex-wrap: wrap;
}

.icon-link {
  color: var(--accent);
  font-size: 0.875rem;
  font-weight: 500;
  transition: opacity var(--transition);
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.icon-link::after { content: ' ↗'; font-size: 0.7rem; opacity: 0.7; }
.icon-link:hover { opacity: 0.7; }

.about-image { display: flex; justify-content: center; }

.img-wrapper {
  width: 220px;
  height: 220px;
  border-radius: var(--radius);
  overflow: hidden;
  border: 2px solid var(--border);
  box-shadow: var(--shadow-lg);
  position: relative;
}

.img-wrapper::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--accent-dim), transparent 60%);
  pointer-events: none;
}

.img-wrapper img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(15%);
  transition: filter 0.4s;
}

.img-wrapper:hover img { filter: grayscale(0%); }

/* ================================================
   Skills
   ================================================ */
#skills { background: var(--surface); }

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.5rem;
}

.skill-category {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: border-color var(--transition);
}

.skill-category:hover { border-color: var(--accent); }

.skill-category h3 {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.skill-tags { display: flex; flex-wrap: wrap; gap: 0.5rem; }

.tag {
  display: inline-block;
  padding: 0.25rem 0.7rem;
  border-radius: 4px;
  font-size: 0.8125rem;
  font-weight: 500;
  background: var(--surface-2);
  color: var(--text-secondary);
  border: 1px solid var(--border);
  transition: border-color var(--transition), color var(--transition);
}

.tag:hover { border-color: var(--accent); color: var(--text-primary); }

.tag-primary {
  background: var(--accent-dim);
  color: var(--accent);
  border-color: rgba(167, 139, 250, 0.3);
}

/* ================================================
   Experience Timeline
   ================================================ */
#experience { background: var(--bg); }

.timeline {
  position: relative;
  padding-left: 2rem;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 2rem;
  width: 2px;
  background: linear-gradient(to bottom, var(--accent) 0%, var(--border) 100%);
}

.timeline-item {
  position: relative;
  padding-bottom: 2.5rem;
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.timeline-item.visible { opacity: 1; transform: translateY(0); }
.timeline-item:last-child { padding-bottom: 0; }

.timeline-dot {
  position: absolute;
  left: -2.375rem;
  top: 7px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--bg);
  box-shadow: 0 0 0 2px var(--accent);
}

.timeline-content {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
  transition: border-color var(--transition);
}

.timeline-content:hover { border-color: rgba(167, 139, 250, 0.4); }

.timeline-header {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.5rem 0.75rem;
  margin-bottom: 0.25rem;
}

.timeline-header h3 { font-size: 1.0625rem; font-weight: 600; }
.timeline-company { color: var(--accent); font-size: 0.9375rem; font-weight: 500; }

.timeline-date {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.timeline-content > p { color: var(--text-secondary); font-size: 0.9375rem; }
.timeline-content ul { display: flex; flex-direction: column; gap: 0.5rem; }

.timeline-content li {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  padding-left: 1.25rem;
  position: relative;
  line-height: 1.6;
}

.timeline-content li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-size: 0.7rem;
  top: 0.22em;
}

/* ================================================
   Blog Preview
   ================================================ */
#blog-preview { background: var(--surface); }

.section-sub {
  color: var(--text-secondary);
  margin-top: -2rem;
  margin-bottom: 2.5rem;
  font-size: 0.9375rem;
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.blog-card {
  display: flex;
  flex-direction: column;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  transition: border-color var(--transition), transform var(--transition);
}

.blog-card:hover { border-color: var(--accent); transform: translateY(-2px); }

.blog-tag {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.875rem;
  display: block;
}

.blog-card h3 {
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.45;
  margin-bottom: 0.75rem;
  transition: color var(--transition);
}

.blog-card:hover h3 { color: var(--accent); }

.blog-card > p {
  color: var(--text-secondary);
  font-size: 0.875rem;
  line-height: 1.65;
  flex: 1;
  margin-bottom: 1.25rem;
}

.blog-date {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--text-muted);
  display: block;
}

.blog-card-more {
  align-items: center;
  justify-content: center;
  min-height: 120px;
  border-style: dashed;
  border-color: var(--surface-2);
}

.more-label { color: var(--accent); font-size: 1rem; font-weight: 500; }

/* ================================================
   Contact
   ================================================ */
#contact { background: var(--bg); }

.contact-inner {
  text-align: center;
  max-width: 600px;
  margin: 0 auto;
}

.contact-inner .section-title { justify-content: center; }
.contact-inner .section-title::after { display: none; }

.contact-inner > p {
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  font-size: 1.0625rem;
  line-height: 1.7;
}

.social-row {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-top: 2.5rem;
  flex-wrap: wrap;
}

.social-row a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  transition: color var(--transition);
}

.social-row a:hover { color: var(--accent); }

/* ================================================
   Footer
   ================================================ */
footer {
  border-top: 1px solid var(--border);
  padding: 2rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8125rem;
  font-family: var(--font-mono);
  line-height: 1.6;
}

footer p + p { margin-top: 0.5rem; }
footer a { color: var(--accent); transition: opacity var(--transition); }
footer a:hover { opacity: 0.7; }

/* ================================================
   Blog Pages — Layout
   ================================================ */
.page-header {
  max-width: 1100px;
  margin: 0 auto;
  padding: 8rem 2rem 4rem;
}

.page-header h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  letter-spacing: -1px;
  margin-bottom: 0.75rem;
}

.page-header p { color: var(--text-secondary); font-size: 1.0625rem; }

.blog-listing {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem 6rem;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

/* ================================================
   Blog Post Prose
   ================================================ */
.post-layout {
  max-width: 720px;
  margin: 0 auto;
  padding: 8rem 2rem 6rem;
}

.post-header { margin-bottom: 3rem; }
.post-header .blog-tag { font-size: 0.75rem; margin-bottom: 1rem; }

.post-header h1 {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 700;
  letter-spacing: -1px;
  line-height: 1.2;
  margin-bottom: 1rem;
}

.post-meta {
  display: flex;
  gap: 1.5rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  flex-wrap: wrap;
}

.post-divider { border: none; border-top: 1px solid var(--border); margin: 2.5rem 0; }

.prose { color: var(--text-secondary); font-size: 1.0625rem; line-height: 1.8; }
.prose h2 { color: var(--text-primary); font-size: 1.375rem; font-weight: 600; margin: 2.5rem 0 1rem; letter-spacing: -0.3px; }
.prose h3 { color: var(--text-primary); font-size: 1.125rem; font-weight: 600; margin: 2rem 0 0.75rem; }
.prose p { margin-bottom: 1.25rem; }
.prose a { color: var(--accent); text-decoration: underline; text-underline-offset: 3px; }
.prose a:hover { opacity: 0.8; }
.prose strong { color: var(--text-primary); font-weight: 600; }
.prose em { font-style: italic; }

.prose code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--surface-2);
  border: 1px solid var(--border);
  padding: 0.15em 0.45em;
  border-radius: 4px;
  color: var(--accent);
}

.prose pre {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  overflow-x: auto;
  margin: 1.5rem 0;
}

.prose pre code {
  background: none;
  border: none;
  padding: 0;
  color: var(--text-primary);
  font-size: 0.875rem;
  line-height: 1.7;
}

.prose ul { list-style: none; margin: 1rem 0 1.25rem; display: flex; flex-direction: column; gap: 0.5rem; }
.prose ul li { padding-left: 1.5rem; position: relative; }
.prose ul li::before { content: '▸'; position: absolute; left: 0; color: var(--accent); font-size: 0.7rem; top: 0.3em; }

.prose blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.75rem 1.25rem;
  margin: 1.5rem 0;
  background: var(--accent-dim);
  border-radius: 0 var(--radius) var(--radius) 0;
  font-style: italic;
}

.post-footer {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.back-link { color: var(--accent); font-size: 0.875rem; font-weight: 500; transition: opacity var(--transition); }
.back-link:hover { opacity: 0.7; }

/* ================================================
   Animations
   ================================================ */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes scrollPulse {
  0%, 100% { opacity: 0.2; transform: scaleX(0.8); }
  50%       { opacity: 1;   transform: scaleX(1); }
}

/* ================================================
   Responsive
   ================================================ */
@media (max-width: 900px) {
  .about-grid { grid-template-columns: 1fr; }
  .about-image { order: -1; }
  .img-wrapper { width: 160px; height: 160px; }
}

@media (max-width: 768px) {
  .nav-links:not(.open) { display: none; }
  .hamburger { display: flex; }
  section { padding: 4rem 0; }
  .hero-name { letter-spacing: -0.5px; }
  .timeline { padding-left: 1.5rem; }
  .timeline-dot { left: -1.875rem; }
}

@media (max-width: 480px) {
  .section-title { font-size: 1.375rem; }
  .timeline-content { padding: 1.25rem; }
  .skills-grid { grid-template-columns: 1fr; }
  .blog-listing { grid-template-columns: 1fr; }
}