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

:root {
  --bg: #f8f9fa;
  --surface: #ffffff;
  --border: #e9ecef;
  --text-primary: #1a1a2e;
  --text-secondary: #6c757d;
  --accent: #4361ee;
  --accent-light: #eef0fd;
  --radius: 12px;
  --shadow: 0 2px 16px rgba(0,0,0,0.07);
  --shadow-hover: 0 8px 32px rgba(67,97,238,0.15);
  --transition: 0.25s ease;
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
}

/* NAV */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 1100px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 2rem; height: 60px;
}
.nav-logo {
  font-weight: 700; font-size: 1.1rem; color: var(--accent);
  text-decoration: none; letter-spacing: -0.5px;
}
.nav-links { display: flex; gap: 2rem; list-style: none; }
.nav-links a {
  font-size: 0.9rem; font-weight: 500;
  color: var(--text-secondary); text-decoration: none;
  transition: color var(--transition);
}
.nav-links a:hover { color: var(--accent); }

/* SECTIONS */
section { padding: 100px 2rem; }
.container { max-width: 1100px; margin: 0 auto; }

.section-label {
  display: inline-block;
  font-size: 0.75rem; font-weight: 700; letter-spacing: 2px;
  text-transform: uppercase; color: var(--accent);
  background: var(--accent-light);
  padding: 4px 12px; border-radius: 20px;
  margin-bottom: 0.75rem;
}
.section-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 800; letter-spacing: -1px;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}
.section-sub {
  color: var(--text-secondary); font-size: 1rem;
  margin-bottom: 3rem;
}

/* HERO */
#hero {
  min-height: 100vh;
  display: flex; align-items: center;
  padding-top: 60px;
  background: linear-gradient(135deg, #f8f9fa 0%, #eef0fd 100%);
}
.hero-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 3rem; flex-wrap: wrap;
}
.hero-text { flex: 1; min-width: 280px; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 0.85rem; font-weight: 600; color: var(--accent);
  background: var(--accent-light); padding: 6px 14px; border-radius: 20px;
  margin-bottom: 1.5rem;
}
.hero-badge::before {
  content: ''; width: 8px; height: 8px; border-radius: 50%;
  background: var(--accent); animation: pulse 2s infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.3); }
}
.hero-name-ko {
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  font-weight: 600; color: var(--text-secondary);
  margin-bottom: 0.25rem;
}
.hero-name-en {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 900; letter-spacing: -2px;
  color: var(--text-primary); line-height: 1;
  margin-bottom: 1.25rem;
}
.hero-name-en span { color: var(--accent); }
.hero-desc {
  font-size: 1.1rem; color: var(--text-secondary);
  max-width: 480px; line-height: 1.8;
  margin-bottom: 2rem;
}
.hero-cta { display: flex; gap: 1rem; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 24px; border-radius: 8px;
  font-size: 0.9rem; 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: #3451d1; transform: translateY(-2px); box-shadow: var(--shadow-hover); }
.btn-outline {
  background: transparent; color: var(--accent);
  border: 2px solid var(--accent);
}
.btn-outline:hover { background: var(--accent-light); transform: translateY(-2px); }

.hero-avatar {
  flex-shrink: 0;
  width: 280px; height: 280px;
  border-radius: 32px;
  background: linear-gradient(135deg, var(--accent) 0%, #7b2ff7 100%);
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 20px 60px rgba(67,97,238,0.25);
  position: relative; overflow: hidden;
}
.hero-avatar::before {
  content: '';
  position: absolute; inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.08'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}
.hero-avatar-inner {
  font-size: 6rem; line-height: 1;
  user-select: none; position: relative;
}

/* SKILLS */
#skills { background: var(--surface); }
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}
.skill-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  transition: all var(--transition);
}
.skill-card:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
}
.skill-card-title {
  display: flex; align-items: center; gap: 10px;
  font-size: 1rem; font-weight: 700;
  margin-bottom: 1.25rem; color: var(--text-primary);
}
.skill-icon {
  width: 36px; height: 36px; border-radius: 8px;
  background: var(--accent-light);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem;
}
.skill-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.tag {
  font-size: 0.8rem; font-weight: 600;
  padding: 4px 12px; border-radius: 6px;
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text-secondary);
  transition: all var(--transition);
}
.tag:hover { background: var(--accent-light); border-color: var(--accent); color: var(--accent); }

/* PROJECTS */
#projects { background: var(--bg); }
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
}
.project-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition);
}
.project-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-hover); }
.project-thumb {
  height: 180px;
  display: flex; align-items: center; justify-content: center;
  font-size: 3rem;
  position: relative; overflow: hidden;
}
.project-thumb-1 { background: linear-gradient(135deg, #e0f2fe, #bae6fd); }
.project-thumb-2 { background: linear-gradient(135deg, #f0fdf4, #bbf7d0); }
.project-thumb-3 { background: linear-gradient(135deg, #fdf4ff, #f5d0fe); }
.project-thumb-4 { background: linear-gradient(135deg, #fff7ed, #fed7aa); }
.project-body { padding: 1.5rem; }
.project-type {
  font-size: 0.72rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1.5px; color: var(--accent); margin-bottom: 0.5rem;
}
.project-title {
  font-size: 1.15rem; font-weight: 700;
  color: var(--text-primary); margin-bottom: 0.5rem;
}
.project-desc {
  font-size: 0.875rem; color: var(--text-secondary);
  line-height: 1.7; margin-bottom: 1.25rem;
}
.project-footer {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 0.5rem;
}
.project-tags { display: flex; gap: 6px; flex-wrap: wrap; }
.project-tag {
  font-size: 0.72rem; font-weight: 600;
  padding: 3px 10px; border-radius: 4px;
  background: var(--accent-light); color: var(--accent);
}
.project-link {
  font-size: 0.82rem; font-weight: 600;
  color: var(--accent); text-decoration: none;
  display: flex; align-items: center; gap: 4px;
  transition: gap var(--transition);
}
.project-link:hover { gap: 8px; }

/* CONTACT */
#contact {
  background: var(--text-primary);
  color: #fff;
}
#contact .section-label { background: rgba(255,255,255,0.1); color: #a5b4fc; }
#contact .section-title { color: #fff; }
#contact .section-sub { color: rgba(255,255,255,0.5); }
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem; align-items: start;
}
.contact-text p {
  color: rgba(255,255,255,0.65); line-height: 1.8;
  margin-bottom: 2rem;
}
.contact-links { display: flex; flex-direction: column; gap: 1rem; }
.contact-link {
  display: flex; align-items: center; gap: 1rem;
  padding: 1rem 1.25rem;
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius);
  text-decoration: none; color: #fff;
  transition: all var(--transition);
}
.contact-link:hover {
  background: rgba(67,97,238,0.3);
  border-color: var(--accent);
  transform: translateX(6px);
}
.contact-link-icon {
  width: 42px; height: 42px;
  border-radius: 10px; background: rgba(255,255,255,0.1);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem; flex-shrink: 0;
}
.contact-link-info strong {
  display: block; font-size: 0.9rem; font-weight: 700;
}
.contact-link-info span {
  font-size: 0.8rem; color: rgba(255,255,255,0.5);
}
.contact-form { display: flex; flex-direction: column; gap: 1rem; }
.form-group { display: flex; flex-direction: column; gap: 6px; }
.form-label { font-size: 0.82rem; font-weight: 600; color: rgba(255,255,255,0.6); }
.form-input, .form-textarea {
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 8px;
  padding: 12px 16px;
  color: #fff; font-size: 0.9rem;
  font-family: inherit;
  transition: border-color var(--transition);
  outline: none;
  resize: none;
}
.form-input::placeholder, .form-textarea::placeholder { color: rgba(255,255,255,0.25); }
.form-input:focus, .form-textarea:focus { border-color: var(--accent); }
.form-textarea { height: 120px; }
.btn-white {
  background: #fff; color: var(--accent);
}
.btn-white:hover { background: var(--accent-light); transform: translateY(-2px); }

/* FOOTER */
footer {
  background: #0f0f1a;
  color: rgba(255,255,255,0.35);
  text-align: center;
  padding: 2rem;
  font-size: 0.82rem;
}
footer a { color: rgba(255,255,255,0.5); text-decoration: none; }
footer a:hover { color: #fff; }

/* FADE IN */
.fade-up {
  opacity: 0; transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-up.visible { opacity: 1; transform: translateY(0); }

/* RESPONSIVE */
@media (max-width: 768px) {
  section { padding: 80px 1.25rem; }
  .contact-grid { grid-template-columns: 1fr; }
  .hero-avatar { width: 200px; height: 200px; }
  .hero-avatar-inner { font-size: 4.5rem; }
  .nav-links { gap: 1.25rem; }
}
@media (max-width: 480px) {
  .nav-links { display: none; }
}