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

:root {
  --bg: #0f172a;
  --bg-card: #1e293b;
  --bg-card-hover: #263044;
  --border: #334155;
  --accent: #38bdf8;
  --accent-dim: rgba(56, 189, 248, 0.15);
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --text-faint: #64748b;
  --radius: 12px;
  --nav-height: 64px;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

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

a {
  color: var(--accent);
  text-decoration: none;
  transition: opacity 0.2s;
}

a:hover {
  opacity: 0.8;
}

/* ===== Layout ===== */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

section {
  padding: 96px 0;
}

/* ===== Section Title ===== */
.section-title {
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  font-weight: 700;
  color: var(--text);
  margin-bottom: 56px;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: var(--accent);
  margin-top: 10px;
  border-radius: 2px;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--accent);
  color: #0f172a;
  border-color: var(--accent);
}

.btn-primary:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

.btn-outline {
  background: transparent;
  color: var(--accent);
  border-color: var(--accent);
}

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

/* ===== Navbar ===== */
#navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--nav-height);
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s;
}

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

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: -0.5px;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 36px;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent);
  opacity: 1;
}

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

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all 0.3s;
}

/* ===== Hero ===== */
#hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 0 24px;
  position: relative;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(56,189,248,0.07) 0%, transparent 70%);
}

.hero-greeting {
  color: var(--accent);
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: 8px;
  letter-spacing: 0.05em;
}

.hero-name {
  font-size: clamp(2.8rem, 8vw, 5rem);
  font-weight: 800;
  line-height: 1.1;
  color: var(--text);
  letter-spacing: -1px;
  margin-bottom: 12px;
}

.hero-title {
  font-size: clamp(1.3rem, 3vw, 1.8rem);
  font-weight: 400;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.hero-tagline {
  max-width: 560px;
  color: var(--text-muted);
  font-size: 1.05rem;
  margin-bottom: 40px;
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 40px;
}

.hero-social {
  display: flex;
  gap: 20px;
}

.hero-social a {
  color: var(--text-muted);
  transition: color 0.2s;
}

.hero-social a:hover {
  color: var(--accent);
  opacity: 1;
}

.hero-scroll-hint {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  color: var(--text-faint);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(6px); }
}

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

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}

.about-text p {
  color: var(--text-muted);
  margin-bottom: 18px;
  font-size: 1.05rem;
}

.about-highlights {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.highlight-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: border-color 0.2s, background 0.2s;
}

.highlight-card:hover {
  border-color: var(--accent);
  background: var(--bg-card-hover);
}

.highlight-icon {
  font-size: 1.6rem;
  display: block;
  margin-bottom: 10px;
}

.highlight-card h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 6px;
}

.highlight-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* ===== Skills ===== */
#skills {
  background: rgba(30, 41, 59, 0.4);
}

.skills-categories {
  display: flex;
  flex-direction: column;
  gap: 40px;
}

.skill-group-title {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: 14px;
}

.skill-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.badge {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 16px;
  border-radius: 999px;
  font-size: 0.875rem;
  font-weight: 500;
  transition: border-color 0.2s, background 0.2s, color 0.2s;
  cursor: default;
}

.badge:hover {
  border-color: var(--accent);
  background: var(--accent-dim);
  color: var(--accent);
}

/* ===== Projects ===== */
#projects {
  background: var(--bg);
}

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

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: border-color 0.25s, transform 0.25s, background 0.25s;
}

.project-card:hover {
  border-color: var(--accent);
  background: var(--bg-card-hover);
  transform: translateY(-4px);
}

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

.project-icon {
  color: var(--accent);
}

.project-links a {
  color: var(--text-muted);
  transition: color 0.2s;
}

.project-links a:hover {
  color: var(--accent);
  opacity: 1;
}

.project-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
}

.project-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.7;
  flex: 1;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 4px;
}

.tag {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-dim);
  padding: 3px 10px;
  border-radius: 999px;
}

/* ===== Contact ===== */
#contact {
  background: rgba(30, 41, 59, 0.4);
  text-align: center;
}

.contact-sub {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 500px;
  margin: 0 auto 40px;
}

.contact-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

.contact-links {
  display: flex;
  gap: 32px;
  justify-content: center;
}

.contact-link {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.2s;
}

.contact-link:hover {
  color: var(--accent);
  opacity: 1;
}

/* ===== Footer ===== */
footer {
  text-align: center;
  padding: 32px 24px;
  color: var(--text-faint);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
}

/* ===== Fade-in animation ===== */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  section {
    padding: 72px 0;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    gap: 0;
    padding: 8px 0;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li a {
    display: block;
    padding: 14px 24px;
  }

  .nav-toggle {
    display: flex;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

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

  .hero-actions {
    flex-direction: column;
    align-items: center;
  }
}

@media (max-width: 480px) {
  .hero-name {
    font-size: 2.4rem;
  }

  .contact-links {
    flex-direction: column;
    align-items: center;
  }
}