/* FOUT 방지: Space Grotesk 메트릭에 맞춘 폴백 폰트 정의 */
@font-face {
  font-family: 'Space Grotesk Fallback';
  src: local('Arial');
  size-adjust: 100%;
  ascent-override: 88%;
  descent-override: 22%;
  line-gap-override: 0%;
}

:root {
  --accent: #FF6B2B;
  --bg: #0E0E0E;
  --bg2: #181818;
  --bg3: #222222;
  --text: #F0EDE8;
  --text2: #999;
  --border: rgba(255,255,255,0.08);
  --card-bg: #181818;
  --section-px: 2rem;
}
.light-mode {
  --accent: #1A6FD4;
  --bg: #F5F4F1;
  --bg2: #FFFFFF;
  --bg3: #EEECEA;
  --text: #111;
  --text2: #666;
  --border: rgba(0,0,0,0.08);
  --card-bg: #FFFFFF;
}

::selection {
  background: var(--accent);
  color: #fff;
}

body {
  font-family: 'Space Grotesk', 'Space Grotesk Fallback', 'Noto Sans KR', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  transition: background 0.3s, color 0.3s;
  margin: 0;
  padding: 0;
}

/* NAV */
.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.25rem var(--section-px);
  border-bottom: 1px solid var(--border);
  background: var(--bg);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav-logo {
  font-family: 'Syne', sans-serif;
  font-weight: 800;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
  color: var(--accent);
}
.nav-right { display: flex; align-items: center; gap: 0.75rem; }
.nav-links { display: flex; gap: 1.5rem; align-items: center; }
.nav-links a {
  font-size: 0.8rem;
  color: var(--text2);
  text-decoration: none;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  transition: color 0.2s;
  cursor: pointer;
  white-space: nowrap;
}
.nav-links a:hover { color: var(--accent); }

.theme-toggle {
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text);
  width: 36px; height: 36px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 0.9rem;
  display: flex; align-items: center; justify-content: center;
  transition: background 0.2s;
  flex-shrink: 0;
  position: relative;
}
.theme-toggle:hover { background: var(--accent); color: #fff; }
.theme-toggle .icon-outline { display: flex; }
.theme-toggle .icon-filled { display: none; }
.theme-toggle:hover .icon-outline { display: none; }
.theme-toggle:hover .icon-filled { display: flex; }

.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: var(--bg3);
  border: 1px solid var(--border);
  width: 36px; height: 36px;
  border-radius: 8px;
  cursor: pointer;
  padding: 8px;
  flex-shrink: 0;
}
.hamburger span {
  display: block;
  height: 1.5px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}
.hamburger.open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

.mobile-menu {
  display: none;
  flex-direction: column;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 1rem var(--section-px);
  gap: 0.25rem;
}
.mobile-menu.open { display: flex; }
.mobile-menu a {
  font-size: 0.9rem;
  color: var(--text2);
  text-decoration: none;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  transition: color 0.2s;
}
.mobile-menu a:last-child { border-bottom: none; }
.mobile-menu a:hover { color: var(--accent); }

/* LAYOUT */
.divider { height: 1px; background: var(--border); max-width: 900px; margin: 0 auto; }
.section { padding: 4rem var(--section-px); max-width: 900px; margin: 0 auto; }

.section-label {
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 2rem;
  display: flex; align-items: center; gap: 0.75rem;
}

.section-label.collapsible { cursor: pointer; user-select: none; }
.section-label.collapsible:hover { opacity: 0.8; }
.section-label.collapsible.collapsed { margin-bottom: 0; }

.collapse-icon {
  display: flex;
  align-items: center;
  color: var(--text2);
  flex-shrink: 0;
}
.section-label.collapsed .collapse-icon { transform: rotate(180deg); }

.collapsible-body {
  display: grid;
  grid-template-rows: 1fr;
  transition: grid-template-rows 0.4s ease, opacity 0.3s ease;
  opacity: 1;
}
.collapsible-body.collapsed {
  grid-template-rows: 0fr;
  opacity: 0;
}
.collapsible-body > div { overflow: hidden; }

/* HERO */
.hero { padding: 5rem var(--section-px) 4rem; max-width: 900px; margin: 0 auto; }
.hero-tag {
  display: inline-block;
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  border: 1px solid var(--accent);
  padding: 0.3rem 0.75rem;
  border-radius: 2rem;
  margin-bottom: 2rem;
}
.hero-name {
  font-family: 'Syne', sans-serif;
  font-size: clamp(2.2rem, 8vw, 4.5rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 1.5rem;
  overflow: visible;
  padding-bottom: 0.1em;
}
.cursor {
  display: inline-block;
  color: var(--accent);
  animation: blink 1s step-end infinite;
  margin-left: 2px;
  font-weight: 300;
  font-size: 0.85em;
}
@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}
.hero-title {
  font-family: 'Space Grotesk', 'Space Grotesk Fallback', sans-serif;
  font-size: clamp(1rem, 3vw, 2rem);
  font-weight: 400;
  color: var(--text2);
  margin-bottom: 2rem;
  letter-spacing: -0.01em;
}
.hero-desc {
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--text2);
  max-width: 720px;
  margin-bottom: 2.5rem;
}
.hero-cta { display: flex; gap: 1rem; flex-wrap: wrap; }

.btn-primary {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 0.75rem 1.75rem;
  border-radius: 2rem;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  letter-spacing: 0.02em;
  transition: opacity 0.2s, transform 0.15s;
}
.btn-primary:hover { opacity: 0.85; transform: translateY(-1px); }
.btn-secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
  padding: 0.75rem 1.75rem;
  border-radius: 2rem;
  font-size: 0.85rem;
  cursor: pointer;
  letter-spacing: 0.02em;
  transition: border-color 0.2s, color 0.2s;
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

/* STATS */
.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 1rem; margin-bottom: 3rem; }
.stat-card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 12px; padding: 1.25rem; text-align: center; }
.stat-num {
  font-family: 'Space Grotesk', 'Space Grotesk Fallback', sans-serif;
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--accent);
  display: flex;
  justify-content: center;
  align-items: center;
  margin-bottom: 0.25rem;
  gap: 0.05em;
}
.stat-num-slot {
  display: inline-block;
  overflow: hidden;
  height: 2.2rem;
  line-height: 2.2rem;
  position: relative;
  min-width: 1ch;
}
.stat-unit {
  display: inline-block;
  line-height: 2.2rem;
}
.stat-num-inner {
  position: absolute;
  left: 0;
  width: 100%;
  text-align: center;
  line-height: 2.2rem;
}
.stat-label { font-size: 0.73rem; color: var(--text2); letter-spacing: 0.02em; }

/* SKILLS */
.skills-list { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 1.5rem; }
.skill-tag {
  background: var(--bg3); border: 1px solid var(--border);
  color: var(--text); padding: 0.4rem 0.9rem;
  border-radius: 2rem; font-size: 0.8rem;
  transition: border-color 0.2s, color 0.2s;
}
.skill-tag:hover { border-color: var(--accent); color: var(--accent); font-weight: 600; }
.skill-tag.accent { border-color: var(--accent); color: var(--accent); }

/* EXPERIENCE */
.experience-item {
  border-left: 2px solid var(--border);
  padding-left: 1.5rem;
  margin-bottom: 2.5rem;
  position: relative;
}
.experience-item::before {
  content: '';
  position: absolute;
  left: -5px; top: 6px;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--accent);
}

.exp-period { font-size: 0.75rem; color: var(--accent); letter-spacing: 0.05em; margin-bottom: 0.3rem; }
.exp-company { font-family: 'Space Grotesk', 'Space Grotesk Fallback', sans-serif; font-size: 1.1rem; font-weight: 700; margin-bottom: 0.2rem; }
.exp-role { font-size: 0.85rem; color: var(--text2); margin-bottom: 0.75rem; }
.exp-desc { font-size: 0.875rem; line-height: 1.75; color: var(--text2); }

/* PROJECTS */
.project-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(220px, 1fr));
  grid-auto-rows: 8px;
  gap: 1rem;
  align-items: start;
}
.project-card {
  background: var(--card-bg); border: 1px solid var(--border);
  border-radius: 12px; padding: 1.5rem;
  transition: border-color 0.2s, transform 0.2s;
  display: block;
}
.project-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.project-card-tag { font-size: 0.7rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--accent); margin-bottom: 0.75rem; }
.project-card-title { font-family: 'Space Grotesk', 'Space Grotesk Fallback', sans-serif; font-size: 1rem; font-weight: 700; margin-bottom: 0.5rem; }
.project-card-desc { font-size: 0.8rem; line-height: 1.7; color: var(--text2); }
.highlight { color: var(--text); font-weight: 500; }

/* Project preview modal trigger */
button.project-card {
  appearance: none;
  -webkit-appearance: none;
  width: 100%;
  text-align: left;
  font: inherit;
  color: inherit;
  cursor: pointer;
}


/* Modal */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}
.modal-overlay.open { display: flex; }
.modal-box {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 16px;
  max-width: 720px;
  width: 100%;
  max-height: 85vh;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 2rem;
  position: relative;
  scrollbar-width: thin;
  scrollbar-color: color-mix(in srgb, var(--text2) 50%, transparent) transparent;
}
.modal-box::-webkit-scrollbar {
  width: 8px;
}
.modal-box::-webkit-scrollbar-track {
  background: transparent;
  border-radius: 16px;
}
.modal-box::-webkit-scrollbar-thumb {
  background-color: color-mix(in srgb, var(--text2) 50%, transparent);
  border-radius: 16px;
  border: 2px solid var(--bg2);
}
.modal-box::-webkit-scrollbar-thumb:hover {
  background-color: var(--accent);
}
.modal-close {
  position: absolute;
  top: 1rem; right: 1rem;
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text);
  width: 32px; height: 32px;
  border-radius: 50%;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
}
.modal-close:hover { background: var(--accent); color: #fff; }
.modal-tag { font-size: 0.72rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--accent); margin-bottom: 0.5rem; }
.modal-title { font-family: 'Space Grotesk', 'Space Grotesk Fallback', sans-serif; font-size: 1.3rem; font-weight: 700; margin-bottom: 0.75rem; padding-right: 2rem; }
.modal-desc { font-size: 0.85rem; line-height: 1.7; color: var(--text2); margin-bottom: 1.5rem; }
.modal-screenshots {
  columns: 3 160px;
  column-gap: 0.75rem;
}
.modal-screenshot {
  width: 100%;
  height: auto;
  border-radius: 8px;
  border: 1px solid var(--border);
  display: block;
  background: var(--bg3);
  break-inside: avoid;
  margin-bottom: 0.75rem;
}
.modal-screenshot-placeholder {
  width: 100%;
  aspect-ratio: 16 / 10;
  border-radius: 8px;
  border: 1px dashed var(--border);
  background: var(--bg3);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text2);
  font-size: 0.8rem;
}

/* ACHIEVEMENT LIST */
.achievement-list { list-style: none; display: flex; flex-direction: column; gap: 0.75rem; margin: 0; padding: 0; }
.achievement-list li { font-size: 0.875rem; line-height: 1.7; color: var(--text2); padding-left: 1rem; position: relative; }
.achievement-list li::before { content: '—'; position: absolute; left: 0; color: var(--accent); }

/* OPEN SOURCE */
.open-source-card {
  background: var(--card-bg); border: 1px solid var(--border);
  border-radius: 12px; padding: 1.25rem 1.5rem;
  display: flex; align-items: center; gap: 1rem;
  transition: border-color 0.2s;
}
.open-source-card:hover { border-color: var(--accent); }
.os-icon { width: 36px; height: 36px; border-radius: 8px; background: var(--bg3); display: flex; align-items: center; justify-content: center; font-size: 1rem; flex-shrink: 0; }
.os-title { font-size: 0.9rem; font-weight: 500; margin-bottom: 0.2rem; }
.os-desc { font-size: 0.78rem; color: var(--text2); line-height: 1.5; }

/* GITHUB */
.github-card {
  background: var(--card-bg); border: 1px solid var(--border);
  border-radius: 12px; padding: 1.25rem 1.5rem;
  display: flex; flex-direction: row; align-items: center;
  gap: 1.25rem; text-align: left;
  transition: border-color 0.2s, transform 0.2s;
  cursor: pointer; text-decoration: none;
  max-width: 100%;
}
.github-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.github-icon { width: 40px; height: 40px; border-radius: 10px; background: var(--bg3); display: flex; align-items: center; justify-content: center; font-size: 1.2rem; flex-shrink: 0; }
.github-card-title { font-family: 'Space Grotesk', 'Space Grotesk Fallback', sans-serif; font-size: 1rem; font-weight: 700; color: var(--text); }
.github-card-url { font-size: 0.78rem; color: var(--accent); }
.github-card-desc { font-size: 0.8rem; color: var(--text2); line-height: 1.6; }

.hidden-icon { display: none !important; }

.project-group-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin: 2rem 0 1.25rem;
}
.project-group-header:first-child { margin-top: 0; }
.project-group-label {
  font-family: 'Syne', sans-serif;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text2);
  white-space: nowrap;
}
.project-group-line { flex: 1; height: 1px; background: var(--border); }

.footer {
  border-top: 1px solid var(--border);
  padding: 2rem var(--section-px);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.78rem;
  color: var(--text2);
  max-width: 100%;
}
.footer-left p { margin-top: 0.25rem; }
.footer-github {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text2);
  text-decoration: none;
  font-size: 0.82rem;
  transition: color 0.2s;
}
.footer-github svg { width: 20px; height: 20px; fill: currentColor; }

/* SCROLL TO TOP */
.scroll-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 40px; height: 40px;
  border-radius: 50%;
  background: var(--bg2);
  border: 1px solid var(--border);
  color: var(--text);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s, background 0.2s, transform 0.2s;
  z-index: 99;
}
.scroll-top.visible { opacity: 1; pointer-events: auto; }
.scroll-top:hover { background: var(--accent); color: #fff; animation: bounce-up 0.6s ease infinite; }
@keyframes bounce-up {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-4px); }
}

/* RESPONSIVE */
@media (max-width: 640px) {
  :root { --section-px: 1.25rem; }
  .nav-links { display: none; }
  .hamburger { display: flex; }
  .hero { padding: 3rem var(--section-px) 2.5rem; }
  .section { padding: 3rem var(--section-px); }
  .stat-row { grid-template-columns: repeat(2, 1fr); }
  .project-grid { grid-template-columns: 1fr; }
  .hero-cta { flex-direction: column; }
  .btn-primary, .btn-secondary { text-align: center; }
  .open-source-card { flex-direction: column; align-items: flex-start; }
}

@media (min-width: 641px) and (max-width: 768px) {
  :root { --section-px: 1.5rem; }
  .nav-links { gap: 1rem; }
  .nav-links a { font-size: 0.72rem; }
  .project-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

/* SVG icon sizes */
.svg-icon-sm { width: 16px; height: 16px; }
.svg-icon-os { width: 20px; height: 20px; fill: var(--text2); }
.svg-icon-github { width: 28px; height: 28px; fill: var(--text2); }

/* Skills */
.skills-col { display: flex; flex-direction: column; gap: 1rem; }
.skill-category-label { font-size: 0.75rem; color: var(--text2); margin-bottom: 0.5rem; letter-spacing: 0.05em; }

/* Experience */
.exp-content { padding-left: 4px; }

/* Projects */
.project-section { margin-bottom: 2rem; }
.project-category-label { font-size: 0.8rem; color: var(--text2); margin-bottom: 1.5rem; letter-spacing: 0.05em; text-transform: uppercase; }
a.project-card { text-decoration: none; color: inherit; }
.open-source-section { margin-top: 3.5rem; }
.open-source-list { display: flex; flex-direction: column; gap: 0.75rem; margin-top: 1.5rem; }
a.open-source-card { text-decoration: none; color: inherit; }

/* Personal */
.personal-desc { font-size: 0.875rem; color: var(--text2); margin-bottom: 1.5rem; line-height: 1.7; }

/* Footer */
.footer-logo { font-family: 'Syne', sans-serif; font-weight: 700; color: var(--accent); }