/* ============================================================
   ACADEMIC SLATE NAVY ACCESSIBLE THEME (style.css)
   Target: Neurodiversity (ASD, ADHD, Dyslexia) + Academic Integrity
   Full Dark / Light Dynamic Theme & Component Coverage
============================================================ */

/* 1. Global Variables & Typography Tokens */
:root {
  /* Font Stacks */
  --font-serif-academic: "Newsreader", "Noto Serif KR", "KoPubWorld Batang", serif;
  --font-sans-accessible: "Atkinson Hyperlegible", "Pretendard", "Noto Sans KR", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", Consolas, monospace;

  /* Backward compatibility mappings */
  --font-serif: var(--font-serif-academic);
  --font-body: var(--font-serif-academic);
  --font-sans: var(--font-sans-accessible);

  /* Layout Constants */
  --max-width: 1080px;
  --border-radius-sm: 6px;
  --border-radius-md: 10px;
  --radius-sm: var(--border-radius-sm);
  --radius-md: var(--border-radius-md);
  --transition-speed: 0.25s ease-in-out;
}

/* 2. Slate Navy Dark Theme (Default & [data-theme="dark"]) */
:root,
[data-theme="dark"] {
  /* Canvas & Surfaces */
  --bg-primary: #0e1217;          /* 기본 배경: 깊은 슬레이트 잉크 */
  --bg-surface: #171c24;          /* 카드, 표면 */
  --bg-surface-elevated: #202732; /* 호버 상태, 드롭다운 */
  --bg-subtle: #13171f;           /* Quick Jump 바, 보조 컨테이너 */
  --bg-header: rgba(23, 28, 36, 0.88); /* 헤더 반투명 블러 */
  
  /* Borders & Dividers */
  --border-subtle: #242c38;       /* 카드 기본 테두리 */
  --border-strong: #384456;       /* 호버 및 섹션 구분선 */
  --border-color: var(--border-subtle);

  /* Text & Contrast (WCAG AAA, 100% 순수 화이트 배제로 눈부심 방지) */
  --text-primary: #e6eaf0;        /* 메인 제목, 본문 텍스트 (92% 밝기) */
  --text-secondary: #9da8b9;      /* 부제목, 메타데이터, 설명글 */
  --text-muted: #6b7788;          /* 캡션, 비활성 텍스트, 저작권 */
  --text-main: var(--text-primary);
  --text-brand: var(--accent-primary);

  /* Accents & States */
  --accent-primary: #6eb5ff;      /* 아카데믹 블루 (링크, 기본 뱃지) */
  --accent-primary-hover: #99cbff;
  --accent-hover: var(--accent-primary-hover);
  --accent-mint: #4fd1c5;         /* 프로젝트/진행중 뱃지 */
  --accent-mint-bg: rgba(79, 209, 197, 0.12);
  --accent-blue-bg: rgba(110, 181, 255, 0.12);
  --nav-hover-bg: rgba(255, 255, 255, 0.06);

  /* Button Tokens */
  --btn-primary-bg: #22344a;
  --btn-primary-border: #3d587a;
  --btn-primary-text: #ffffff;
  --btn-primary-hover-bg: #2d4563;

  /* Focus Indicator */
  --focus-ring: 2px solid #6eb5ff;
  --focus-offset: 3px;
}

/* 3. Slate Navy Light Theme ([data-theme="light"]) */
[data-theme="light"] {
  /* Canvas & Surfaces (부드러운 슬레이트 오프화이트로 눈부심 방지) */
  --bg-primary: #f6f8fa;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #eef2f6;
  --bg-subtle: #f0f4f8;
  --bg-header: rgba(255, 255, 255, 0.92); /* 라이트 모드 반투명 화이트 */
  
  /* Borders & Dividers */
  --border-subtle: #d8e0ea;
  --border-strong: #b8c4d4;
  --border-color: var(--border-subtle);

  /* Text & Contrast (WCAG AAA 준수) */
  --text-primary: #121820;        /* 깊은 네이비 차콜 */
  --text-secondary: #4a5568;      /* 슬레이트 그레이 */
  --text-muted: #718096;          /* 비활성 캡션 */
  --text-main: var(--text-primary);
  --text-brand: var(--accent-primary);

  /* Accents & States */
  --accent-primary: #0066cc;      /* 아카데믹 블루 */
  --accent-primary-hover: #004d99;
  --accent-hover: var(--accent-primary-hover);
  --accent-mint: #0d8275;
  --accent-mint-bg: rgba(13, 130, 117, 0.1);
  --accent-blue-bg: rgba(0, 102, 204, 0.08);
  --nav-hover-bg: rgba(0, 0, 0, 0.05);

  /* Button Tokens */
  --btn-primary-bg: #0066cc;
  --btn-primary-border: #0052a3;
  --btn-primary-text: #ffffff;
  --btn-primary-hover-bg: #004d99;

  /* Focus Indicator */
  --focus-ring: 2px solid #0066cc;
  --focus-offset: 3px;
}

/* 4. Base Reset & Layout Setup */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans-accessible);
  line-height: 1.7;
  letter-spacing: 0.015em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-speed), color var(--transition-speed);
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -60px;
  left: 1rem;
  background: var(--accent-primary);
  color: #ffffff;
  padding: 0.5rem 1rem;
  font-weight: 700;
  border-radius: var(--border-radius-sm);
  z-index: 2000;
  transition: top var(--transition-speed);
  text-decoration: none;
}
.skip-link:focus {
  top: 1rem;
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
}

/* 5. Academic Header & Navigation */
.site-header {
  position: sticky;
  top: 0;
  background-color: var(--bg-header);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 1000;
  transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 4.25rem;
}

.brand {
  display: flex;
  align-items: center;
  text-decoration: none;
}

.brand-name {
  font-family: var(--font-serif-academic);
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.nav-desktop .nav-list {
  display: flex;
  list-style: none;
  gap: 1.5rem;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.35rem 0.5rem;
  border-radius: var(--border-radius-sm);
  transition: color var(--transition-speed), background-color var(--transition-speed);
}

.nav-link:hover,
.nav-link[aria-current="page"] {
  color: var(--text-primary);
  background-color: var(--nav-hover-bg);
}

.nav-link[aria-current="page"] {
  font-weight: 700;
  border-bottom: 2px solid var(--accent-primary);
  border-radius: 0;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.btn-theme,
.btn-hamburger {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  padding: 0.4rem 0.8rem;
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  font-size: 0.88rem;
  font-family: var(--font-sans-accessible);
  transition: background var(--transition-speed), border-color var(--transition-speed);
}

.btn-theme:hover,
.btn-hamburger:hover {
  background: var(--border-strong);
}

.btn-hamburger {
  display: none;
  width: 40px;
  height: 40px;
  padding: 8px;
  flex-direction: column;
  justify-content: space-around;
  align-items: center;
}
.btn-hamburger span {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--text-primary);
  border-radius: 2px;
  transition: transform var(--transition-speed), opacity var(--transition-speed);
}

/* Mobile Drawer */
.drawer-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(4px);
  z-index: 1500;
  opacity: 0;
  transition: opacity var(--transition-speed);
}
.drawer-backdrop.active {
  display: block;
  opacity: 1;
}

.mobile-drawer {
  position: fixed;
  top: 0;
  right: -320px;
  width: 280px;
  height: 100vh;
  background: var(--bg-surface);
  border-left: 1px solid var(--border-subtle);
  z-index: 1600;
  display: flex;
  flex-direction: column;
  padding: 2rem 1.5rem;
  transition: transform 0.3s ease-in-out;
}
.mobile-drawer.active {
  transform: translateX(-320px);
}
.drawer-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-subtle);
}
.drawer-close {
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}
.mobile-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.mobile-nav-link {
  display: block;
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-primary);
  padding: 0.75rem 1rem;
  border-radius: var(--border-radius-sm);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  text-decoration: none;
  transition: all var(--transition-speed);
}
.mobile-nav-link:hover, .mobile-nav-link[aria-current="page"] {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

/* 6. Headings & Typography Hierarchy */
.section-header {
  margin-bottom: 1.5rem;
}

h1.hero-title,
h1.section-title {
  font-family: var(--font-serif-academic);
  font-size: 2.25rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.25;
  margin-bottom: 0.75rem;
}

h2.section-title,
h2.cv-block-title {
  font-family: var(--font-serif-academic);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.35;
  padding-bottom: 0.5rem;
  margin: 2.5rem 0 1.5rem 0;
  border-bottom: 1px solid var(--border-strong);
}

h3.card-title,
h3.pub-title,
h3.press-title {
  font-family: var(--font-sans-accessible);
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.45;
  color: var(--text-primary);
  margin-bottom: 0.6rem;
}

/* Link Underline & Descender Clearance */
h3.pub-title a,
h3.card-title a,
h3.press-title a,
.cv-details a,
.pub-item a,
.press-item a,
a.quick-jump-link {
  text-decoration-thickness: 1.5px;
  text-underline-offset: 4px;
  transition: color var(--transition-speed), text-decoration-color var(--transition-speed);
}

h3.pub-title a,
h3.card-title a,
h3.press-title a {
  color: var(--text-primary);
  text-decoration: underline;
  text-decoration-color: var(--border-strong);
}

h3.pub-title a:hover,
h3.card-title a:hover,
h3.press-title a:hover {
  color: var(--accent-primary);
  text-decoration-color: var(--accent-primary);
}

/* 7. Section Spacing & Hero Profile Section (3.5rem top padding across all pages) */
main > section {
  padding: 3.5rem 0 2.5rem 0;
}

.hero-section {
  padding: 3.5rem 0 2.5rem 0;
  border-bottom: 1px solid var(--border-subtle);
}

.hero-content {
  display: flex;
  gap: 2.5rem;
  align-items: flex-start;
}

.hero-avatar-wrap {
  flex-shrink: 0;
}

.hero-avatar {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  border: 2px solid var(--border-strong);
  background-color: var(--bg-surface);
  object-fit: cover;
}

.hero-text {
  flex: 1;
  min-width: 280px;
}

.hero-role {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--accent-primary);
  margin-bottom: 1rem;
}

.hero-bio {
  color: var(--text-secondary);
  font-size: 1rem;
  margin-bottom: 1.5rem;
  max-width: 720px;
  line-height: 1.75;
}

.social-strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.social-badge, .email-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  padding: 0.35rem 0.75rem;
  border-radius: 20px;
  text-decoration: none;
  font-size: 0.85rem;
  transition: background var(--transition-speed), border-color var(--transition-speed), color var(--transition-speed);
}

.social-badge:hover {
  background-color: var(--bg-surface-elevated);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

/* 8. Quick Jump Bar (cv.html, research.html) */
.quick-jump-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  padding: 0.85rem 1.2rem;
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--border-radius-md);
  margin: 1.5rem 0 2rem 0;
}

.quick-jump-title {
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.quick-jump-link {
  color: var(--accent-primary);
  text-decoration: none;
  font-size: 0.88rem;
  font-weight: 500;
  padding: 0.25rem 0.5rem;
  border-radius: var(--border-radius-sm);
  background: rgba(110, 181, 255, 0.08);
  transition: background var(--transition-speed);
}

.quick-jump-link:hover {
  background: rgba(110, 181, 255, 0.2);
}

/* 9. Card Grid & Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(310px, 1fr));
  gap: 1.5rem;
  margin-top: 1.25rem;
}

.card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--border-radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: border-color var(--transition-speed), background-color var(--transition-speed);
}

.card:hover {
  background-color: var(--bg-surface-elevated);
  border-color: var(--border-strong);
}

.card-meta,
.pub-meta,
.press-meta {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 0.6rem;
}

.card-desc,
.cv-details {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.cv-details strong {
  color: var(--text-primary);
}

.pub-list,
.press-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.pub-item,
.press-item {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--border-radius-md);
  padding: 1.35rem 1.5rem;
  transition: border-color var(--transition-speed), background-color var(--transition-speed);
}
.pub-item:hover,
.press-item:hover {
  background-color: var(--bg-surface-elevated);
  border-color: var(--border-strong);
}

/* 10. CV Block & Timeline (cv.html) */
.cv-block {
  margin-bottom: 2.5rem;
}

.cv-timeline {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
  border-left: 2px solid var(--border-strong);
  padding-left: 1.5rem;
  margin-top: 1rem;
}

.cv-item {
  position: relative;
}

.cv-item::before {
  content: '';
  position: absolute;
  left: -1.95rem;
  top: 0.45rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent-primary);
  border: 2px solid var(--bg-primary);
}

.cv-period {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-primary);
  margin-bottom: 0.2rem;
}

.cv-title {
  font-size: 1.2rem;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
  font-weight: 600;
}

.cv-institution {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

/* 11. Badges */
.badge {
  display: inline-block;
  padding: 0.2rem 0.55rem;
  font-size: 0.78rem;
  font-weight: 600;
  border-radius: 4px;
  background-color: var(--accent-blue-bg);
  color: var(--accent-primary);
  border: 1px solid rgba(110, 181, 255, 0.3);
  margin-right: 0.4rem;
}

.badge-mint {
  background-color: var(--accent-mint-bg);
  color: var(--accent-mint);
  border-color: rgba(79, 209, 197, 0.3);
}

/* 12. Buttons & Links */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: var(--btn-primary-bg);
  border: 1px solid var(--btn-primary-border);
  color: var(--btn-primary-text) !important;
  padding: 0.6rem 1.1rem;
  border-radius: var(--border-radius-sm);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  margin-top: 1.25rem;
  transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.btn-primary:hover {
  background-color: var(--btn-primary-hover-bg);
  border-color: var(--accent-primary);
}

.btn-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-speed);
}
.btn-link:hover {
  color: var(--accent-primary-hover);
  text-decoration: underline;
}

/* 13. Footer & Floating TOP */
.site-footer {
  margin-top: 5rem;
  border-top: 1px solid var(--border-subtle);
  padding: 2.5rem 0;
  background-color: var(--bg-surface);
  transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-copyright {
  font-size: 0.88rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  list-style: none;
  gap: 1.5rem;
}

.footer-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.88rem;
  transition: color var(--transition-speed);
}

.footer-link:hover {
  color: var(--accent-primary);
}

.back-to-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  background-color: var(--bg-surface-elevated);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  text-decoration: none;
  padding: 0.5rem 0.8rem;
  border-radius: var(--border-radius-sm);
  font-size: 0.82rem;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  z-index: 900;
  transition: all var(--transition-speed);
}
.back-to-top:hover {
  background-color: var(--accent-primary);
  color: #ffffff;
}

/* 14. Accessibility Focus States */
a:focus-visible,
button:focus-visible {
  outline: var(--focus-ring);
  outline-offset: var(--focus-offset);
}

/* 15. Responsive Adjustments */
@media (max-width: 860px) {
  .hero-content {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
  .social-strip {
    justify-content: center;
  }
  .nav-desktop {
    display: none;
  }
  .btn-hamburger {
    display: flex;
  }
  .card-grid {
    grid-template-columns: 1fr;
  }
}


/* Global Link Styling & Visited Color Persistence */
a,
a:visited {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-speed), text-decoration-color var(--transition-speed);
}

a:hover {
  color: var(--accent-primary-hover);
}

/* Navigation Links Visited Color */
.nav-link,
.nav-link:visited {
  color: var(--text-secondary);
}
.nav-link:hover,
.nav-link[aria-current="page"] {
  color: var(--text-primary);
}

/* Footer Links Visited Color */
.footer-link,
.footer-link:visited {
  color: var(--text-secondary);
}
.footer-link:hover {
  color: var(--accent-primary);
}

/* Social & Badge Links Visited Color */
.social-badge,
.social-badge:visited {
  color: var(--text-primary);
}
.social-badge:hover {
  color: var(--accent-primary);
}

/* Quick Jump Links Visited Color */
.quick-jump-link,
.quick-jump-link:visited {
  color: var(--accent-primary);
}
.quick-jump-link:hover {
  color: var(--accent-primary-hover);
}

/* Button & Card Links Visited Color */
.btn-link,
.btn-link:visited {
  color: var(--accent-primary);
}
.btn-link:hover {
  color: var(--accent-primary-hover);
}

.btn-primary,
.btn-primary:visited {
  color: var(--btn-primary-text) !important;
}

/* Titles and Card Heading Links Visited Color */
h3.pub-title a,
h3.pub-title a:visited,
h3.card-title a,
h3.card-title a:visited,
h3.press-title a,
h3.press-title a:visited {
  color: var(--text-primary);
  text-decoration: underline;
  text-decoration-color: var(--border-strong);
}

h3.pub-title a:hover,
h3.card-title a:hover,
h3.press-title a:hover {
  color: var(--accent-primary);
  text-decoration-color: var(--accent-primary);
}