*,
*::before,
*::after {
  box-sizing: border-box;
}

:root {
  --color-bg: #0d0d0d;
  --color-surface: #141414;
  --color-surface-elevated: #1a1a1a;
  --color-text: #e8e8e8;
  --color-text-muted: #9ca3af;
  --color-accent: #6366f1;
  --color-accent-hover: #4f46e5;
  --color-border: rgba(255, 255, 255, 0.08);
  --font-sans: "DM Sans", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", monospace;
  --max-width: 720px;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-size: 1rem;
}

header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
}

nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-accent);
  text-decoration: none;
  letter-spacing: 0.05em;
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 1.75rem;
}

nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

nav a:hover,
nav a.active {
  color: var(--color-text);
}

main {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 3rem 1.5rem 4rem;
  width: 100%;
}

/* Hero */
.hero {
  padding: 3rem 0 4rem;
  border-bottom: 1px solid var(--color-border);
}

.hero h1 {
  font-size: clamp(2.25rem, 5vw, 3rem);
  font-weight: 700;
  margin: 0 0 0.5rem;
  letter-spacing: -0.03em;
  line-height: 1.2;
}

.hero .tagline {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-accent);
  margin: 0 0 0.25rem;
}

.hero .subtitle {
  font-size: 1rem;
  color: var(--color-text-muted);
  margin: 0 0 1.5rem;
}

.hero-contact {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

.hero-contact a {
  color: var(--color-text);
  text-decoration: none;
  transition: color 0.2s;
}

.hero-contact a:hover {
  color: var(--color-accent);
}

.hero-contact span:not(:first-child):not(:last-child) {
  opacity: 0.5;
  user-select: none;
}

/* Sections */
.section {
  padding: 3rem 0;
  border-bottom: 1px solid var(--color-border);
}

.section:last-of-type {
  border-bottom: none;
}

.section h2 {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--color-accent);
  margin: 0 0 1.5rem;
}

.summary-text {
  margin: 0 0 1rem;
  color: var(--color-text-muted);
  max-width: 65ch;
}

.summary-text strong {
  color: var(--color-text);
}

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}

.skill-category {
  padding: 1rem 1.25rem;
  background: var(--color-surface-elevated);
  border-radius: 8px;
  border: 1px solid var(--color-border);
}

.skill-category h3 {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
  margin: 0 0 0.5rem;
}

.skill-category p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-text);
  line-height: 1.5;
}

/* Experience */
.job {
  margin-bottom: 2.5rem;
}

.job:last-child {
  margin-bottom: 0;
}

.job-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.25rem;
}

.job-header h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0;
}

.job .location {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.job-role {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
}

.job-role strong {
  color: var(--color-text);
}

.job p {
  margin: 0 0 0.75rem;
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

.job ul {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

.job li {
  margin-bottom: 0.35rem;
}

.job li::marker {
  color: var(--color-accent);
}

/* Education */
.patents {
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}

.patents h3 {
  font-size: 0.9rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
}

.patents p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

/* Contact */
.contact-section p {
  margin: 0 0 1.5rem;
  color: var(--color-text-muted);
}

.contact-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 0.6rem 1.25rem;
  background: var(--color-accent);
  color: white;
  text-decoration: none;
  border-radius: 6px;
  font-weight: 500;
  font-size: 0.9rem;
  transition: background 0.2s, color 0.2s;
}

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

.btn-outline {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-outline:hover {
  background: var(--color-surface-elevated);
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* Footer */
footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 1.5rem;
  text-align: center;
}

footer p {
  margin: 0;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* Responsive */
@media (max-width: 640px) {
  nav ul {
    gap: 1rem;
  }

  nav a {
    font-size: 0.85rem;
  }

  .hero-contact {
    flex-direction: column;
    align-items: flex-start;
  }

  .hero-contact span {
    display: none;
  }

  .skills-grid {
    grid-template-columns: 1fr;
  }
}