:root {
  --font-body: 'DM Sans', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --max-width: 1080px;
  --radius: 12px;
  --radius-sm: 8px;
  --transition: 0.25s ease;
}

[data-theme="dark"] {
  --bg: #0a0a0f;
  --bg-alt: #101018;
  --surface: #14141e;
  --border: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(255, 255, 255, 0.12);
  --text: #e8e8ed;
  --text-muted: #7a7a8e;
  --accent: #6e8efb;
  --accent-hover: #8ba4fc;
  --accent-glow: rgba(110, 142, 251, 0.15);
  --tag-bg: rgba(110, 142, 251, 0.08);
  --tag-text: #8ba4fc;
  --tag-border: rgba(110, 142, 251, 0.15);
  --card-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
  --header-bg: rgba(10, 10, 15, 0.8);
  --hero-glow: radial-gradient(ellipse 60% 50% at 50% 40%, rgba(110, 142, 251, 0.06) 0%, transparent 70%);
}

[data-theme="light"] {
  --bg: #fafafa;
  --bg-alt: #f0f0f4;
  --surface: #ffffff;
  --border: rgba(0, 0, 0, 0.06);
  --border-hover: rgba(0, 0, 0, 0.12);
  --text: #18181b;
  --text-muted: #6b6b7b;
  --accent: #4f6df5;
  --accent-hover: #3d5bd9;
  --accent-glow: rgba(79, 109, 245, 0.1);
  --tag-bg: rgba(79, 109, 245, 0.06);
  --tag-text: #4f6df5;
  --tag-border: rgba(79, 109, 245, 0.12);
  --card-shadow: 0 2px 20px rgba(0, 0, 0, 0.04);
  --header-bg: rgba(250, 250, 250, 0.8);
  --hero-glow: radial-gradient(ellipse 60% 50% at 50% 40%, rgba(79, 109, 245, 0.04) 0%, transparent 70%);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background var(--transition), color var(--transition);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 28px;
}

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--header-bg);
  backdrop-filter: blur(20px) saturate(1.2);
  -webkit-backdrop-filter: blur(20px) saturate(1.2);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), background var(--transition);
}

.header.scrolled {
  border-bottom-color: var(--border);
}

.nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 28px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.2px;
  transition: color var(--transition);
}

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

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

.nav-toggle span {
  width: 22px;
  height: 1.5px;
  background: var(--text);
  border-radius: 2px;
  transition: var(--transition);
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 6px 8px;
  cursor: pointer;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  transition: color var(--transition), border-color var(--transition);
}

.theme-toggle:hover {
  color: var(--text);
  border-color: var(--border-hover);
}

[data-theme="dark"] .icon-sun { display: inline; }
[data-theme="dark"] .icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: inline; }

/* Hero */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 28px 80px;
  position: relative;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--hero-glow);
  pointer-events: none;
}

.hero-content {
  position: relative;
}

.hero-tag {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--accent);
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: 20px;
}

.hero-name {
  font-family: var(--font-mono);
  font-size: clamp(2.8rem, 7vw, 5rem);
  font-weight: 800;
  letter-spacing: -2px;
  line-height: 1.05;
  margin-bottom: 20px;
}

.hero-subtitle {
  font-size: clamp(0.9rem, 1.8vw, 1.05rem);
  color: var(--text-muted);
  font-weight: 400;
  margin-bottom: 44px;
  letter-spacing: 0.3px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 24px;
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 0.88rem;
  font-weight: 600;
  text-decoration: none;
  transition: all var(--transition);
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 20px var(--accent-glow);
}

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

.btn-outline:hover {
  border-color: var(--border-hover);
  color: var(--text);
  transform: translateY(-1px);
}

/* Sections */
.section {
  padding: 100px 0;
}

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

.section-title {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 48px;
  letter-spacing: -0.5px;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 0;
  width: 32px;
  height: 2px;
  background: var(--accent);
  border-radius: 1px;
}

/* About */
.about-content {
  max-width: 700px;
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.about-content.visible {
  opacity: 1;
  transform: translateY(0);
}

.about-content p {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 18px;
  line-height: 1.75;
}

.about-highlights {
  display: flex;
  gap: 40px;
  margin-top: 44px;
  flex-wrap: wrap;
}

.highlight {
  display: flex;
  flex-direction: column;
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.highlight.visible {
  opacity: 1;
  transform: translateY(0);
}

.highlight-number {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: -1px;
}

.highlight-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 500;
  margin-top: 4px;
  letter-spacing: 0.3px;
}

/* Projects */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 16px;
}

.project-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  text-decoration: none;
  color: inherit;
  transition: all var(--transition);
  opacity: 0;
  transform: translateY(16px);
}

.project-card.visible {
  opacity: 1;
  transform: translateY(0);
}

.project-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-2px);
  box-shadow: var(--card-shadow);
}

.project-card:hover .project-header svg {
  transform: translate(2px, -2px);
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 12px;
}

.project-header h3 {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.3px;
}

.project-header svg {
  color: var(--text-muted);
  flex-shrink: 0;
  margin-top: 3px;
  transition: transform var(--transition);
}

.project-card p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 20px;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.project-tags span {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 4px 10px;
  background: var(--tag-bg);
  color: var(--tag-text);
  border: 1px solid var(--tag-border);
  border-radius: 6px;
  font-weight: 500;
}

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 28px;
}

.skill-group {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.skill-group.visible {
  opacity: 1;
  transform: translateY(0);
}

.skill-group h3 {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 14px;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.skill-tags span {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 6px 12px;
  background: var(--tag-bg);
  color: var(--tag-text);
  border: 1px solid var(--tag-border);
  border-radius: 6px;
  font-weight: 500;
  transition: all var(--transition);
}

.skill-tags span:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
  transform: translateY(-1px);
}

/* Contact */
.contact-text {
  color: var(--text-muted);
  font-size: 1rem;
  margin-bottom: 28px;
}

.contact-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.contact-link {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.88rem;
  transition: all var(--transition);
}

.contact-link:hover {
  border-color: var(--border-hover);
  transform: translateY(-1px);
  box-shadow: var(--card-shadow);
}

/* Footer */
.footer {
  padding: 28px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
}

/* Mobile */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }

  .nav-links {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--header-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    gap: 0;
    padding: 0;
    border-bottom: 1px solid var(--border);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .nav-links.open { max-height: 320px; }
  .nav-links li { width: 100%; }

  .nav-links a,
  .nav-links button {
    width: 100%;
    padding: 14px 28px;
    display: block;
    text-align: left;
  }

  .nav-links li:last-child { padding: 8px 16px; }
  .projects-grid { grid-template-columns: 1fr; }
  .skills-grid { grid-template-columns: 1fr; }
  .about-highlights { gap: 28px; }
  .hero { padding: 100px 28px 60px; }
  .section { padding: 64px 0; }
}