:root {
  --primary: #0f172a;
  --secondary: #1e293b;
  --muted: #475569;
  --background: #ffffff;
  --section-bg: #f8fafc;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --link-color: #3b82f6;
  --link-hover: #1d4ed8;
  --footer-text: #cbd5e1;
  --border-color: #e2e8f0;
  --header-bg: #0f172a;
  --header-text: #ffffff;
  --header-subtext: #e2e8f0;
  --card-bg: #ffffff;
  --card-border: #e2e8f0;
  --card-shadow: rgba(0, 0, 0, 0.05);
  --card-shadow-hover: rgba(0, 0, 0, 0.1);
  --transition-fast: 150ms ease;
  --transition-normal: 200ms ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --primary: #f1f5f9;
    --secondary: #e2e8f0;
    --muted: #94a3b8;
    --background: #0f172a;
    --section-bg: #1e293b;
    --accent: #60a5fa;
    --accent-hover: #93c5fd;
    --link-color: #60a5fa;
    --link-hover: #93c5fd;
    --footer-text: #94a3b8;
    --border-color: #334155;
    --header-bg: #020617;
    --header-text: #f8fafc;
    --header-subtext: #cbd5e1;
    --card-bg: #1e293b;
    --card-border: #334155;
    --card-shadow: rgba(0, 0, 0, 0.2);
    --card-shadow-hover: rgba(0, 0, 0, 0.3);
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  font-feature-settings: 'cv11', 'ss01';
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-color: var(--background);
  color: var(--secondary);
  line-height: 1.6;
  font-size: 16px;
}

header {
  background-color: var(--header-bg);
  color: var(--header-text);
  padding: 72px 24px;
  position: relative;
}

header::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #3b82f6, #8b5cf6, #ec4899);
}

header .container {
  max-width: 960px;
  margin: 0 auto;
}

header h1 {
  margin: 0;
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.2;
}

header p {
  margin-top: 20px;
  max-width: 720px;
  font-size: 1.125rem;
  color: var(--header-subtext);
  line-height: 1.7;
  font-weight: 400;
}

header a {
  color: var(--link-color);
  transition: color var(--transition-fast);
}

header a:hover {
  color: var(--link-hover);
}

nav {
  margin-top: 24px;
}

nav a {
  display: inline-block;
  margin-right: 24px;
  color: var(--header-subtext);
  font-weight: 500;
  transition: color var(--transition-fast);
}

nav a:hover {
  color: var(--header-text);
  text-decoration: none;
}

section {
  padding: 64px 24px;
}

section.alt {
  background-color: var(--section-bg);
}

.container {
  max-width: 960px;
  margin: 0 auto;
}

h2 {
  font-size: 1.625rem;
  font-weight: 600;
  margin-top: 0;
  margin-bottom: 16px;
  color: var(--primary);
  letter-spacing: -0.02em;
  line-height: 1.3;
}

h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-top: 32px;
  margin-bottom: 12px;
  color: var(--primary);
  letter-spacing: -0.01em;
  line-height: 1.4;
}

p {
  margin-top: 0;
  margin-bottom: 16px;
  color: var(--secondary);
}

ul {
  padding-left: 24px;
  margin-top: 12px;
  margin-bottom: 16px;
}

li {
  margin-bottom: 12px;
  color: var(--secondary);
  line-height: 1.6;
}

/* Skills Grid */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.skill-category h3 {
  margin-top: 0;
  margin-bottom: 12px;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
}

.skill-category ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.skill-category li {
  margin-bottom: 8px;
  color: var(--secondary);
}

/* Project Cards */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.project-card {
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  padding: 24px;
  box-shadow: 0 1px 3px var(--card-shadow);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.project-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px var(--card-shadow-hover);
}

.project-card h3 {
  margin: 0 0 8px 0;
  font-size: 1.125rem;
}

.project-card p {
  margin: 0 0 16px 0;
  font-size: 0.9rem;
  color: var(--muted);
}

.project-card .tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.project-card .tag {
  font-size: 0.75rem;
  padding: 4px 10px;
  background-color: var(--section-bg);
  border-radius: 9999px;
  color: var(--muted);
}

footer {
  background-color: var(--header-bg);
  color: var(--footer-text);
  padding: 40px 24px;
  font-size: 0.875rem;
}

footer .container {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

footer a {
  color: var(--link-color);
  transition: color var(--transition-fast);
}

footer a:hover {
  color: var(--link-hover);
  text-decoration: none;
}

a {
  color: var(--link-color);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--link-hover);
  text-decoration: underline;
  text-underline-offset: 2px;
}

@media (max-width: 768px) {
  .skills-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (max-width: 640px) {
  header {
    padding: 48px 20px;
  }

  header h1 {
    font-size: 2rem;
  }

  header p {
    font-size: 1rem;
  }

  section {
    padding: 48px 20px;
  }

  h2 {
    font-size: 1.375rem;
  }

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

  nav a {
    display: block;
    margin-right: 0;
    margin-bottom: 12px;
  }
}