/* Apple Design System - Academic CV & Portfolio CSS */
:root {
  --color-primary: #0066cc;
  --color-primary-hover: #0071e3;
  --color-primary-dark: #2997ff;
  
  --color-ink: #1d1d1f;
  --color-body: #1d1d1f;
  --color-muted: #7a7a7a;
  --color-hairline: #e0e0e0;
  --color-divider: #f0f0f0;
  
  --color-canvas: #ffffff;
  --color-parchment: #f5f5f7;
  --color-surface-pearl: #fafafc;
  
  --color-dark-canvas: #000000;
  --color-dark-surface: #161617;
  --color-dark-card: #1c1c1e;
  --color-dark-border: #2c2c2e;
  --color-dark-muted: #a1a1a6;

  /* Typography */
  --font-display: "SF Pro Display", -apple-system, BlinkMacSystemFont, "Pretendard", sans-serif;
  --font-text: "SF Pro Text", -apple-system, BlinkMacSystemFont, "Pretendard", sans-serif;
  
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-pill: 9999px;

  --shadow-subtle: 0 4px 16px rgba(0, 0, 0, 0.04);
  --shadow-hover: 0 12px 32px rgba(0, 0, 0, 0.08);
  --shadow-modal: 0 24px 60px rgba(0, 0, 0, 0.18);
  
  --transition-smooth: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--font-text);
  background-color: var(--color-parchment);
  color: var(--color-body);
  line-height: 1.5;
}

h1, h2, h3, h4, h5 {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: -0.025em;
  color: var(--color-ink);
}

a { color: var(--color-primary); text-decoration: none; transition: var(--transition-smooth); }

/* Global Navigation */
.global-nav {
  position: sticky; top: 0; z-index: 1000;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
  height: 54px; display: flex; align-items: center;
}

.nav-container {
  max-width: 1140px; width: 100%; margin: 0 auto; padding: 0 24px;
  display: flex; justify-content: space-between; align-items: center;
}

.brand-logo {
  font-family: var(--font-display); font-weight: 600; font-size: 17px;
  color: var(--color-ink); display: flex; align-items: center; gap: 8px;
}

.nav-menu { display: flex; gap: 24px; list-style: none; }
.nav-link { font-size: 13px; color: #515154; letter-spacing: -0.01em; }
.nav-link:hover, .nav-link.active { color: var(--color-primary); }

.btn-linkedin {
  font-size: 12px; font-weight: 600; padding: 6px 16px;
  border-radius: var(--radius-pill); background: #0077b5; color: #ffffff;
  display: flex; align-items: center; gap: 6px;
}

.btn-linkedin:hover { background: #005885; color: #fff; }

/* Hero Section - Apple Design Profile Canvas */
.hero-section {
  padding: 40px 24px 60px 24px;
  background-color: var(--color-parchment);
}

.hero-card-container {
  max-width: 1040px;
  margin: 0 auto;
}

.profile-hero-card {
  position: relative;
  background: #ffffff;
  border-radius: 28px;
  border: 1px solid rgba(0, 0, 0, 0.08);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.06);
  overflow: hidden;
  padding: 44px 48px 36px 48px;
}

/* Background Blue Glow Aura (Matches user reference image) */
.hero-glow-bg {
  position: absolute;
  top: -25%;
  right: 0%;
  width: 650px;
  height: 650px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(0, 102, 255, 0.75) 0%, rgba(20, 80, 240, 0.45) 40%, rgba(0, 102, 255, 0.1) 65%, transparent 80%);
  filter: blur(55px);
  pointer-events: none;
  z-index: 1;
}

.hero-content {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
}

.hero-text-side {
  flex: 1;
  padding-bottom: 0px;
  max-width: 520px;
}

.hero-name-ko {
  font-size: 42px;
  font-weight: 700;
  color: #1d1d1f;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 4px;
}

.hero-name-en {
  font-size: 22px;
  font-weight: 600;
  color: #0066cc;
  letter-spacing: -0.01em;
  margin-bottom: 28px;
}

.hero-field-tag {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 15px;
  margin-bottom: 24px;
  background: rgba(245, 245, 247, 0.85);
  backdrop-filter: blur(10px);
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(0, 0, 0, 0.06);
}

.field-label {
  font-weight: 700;
  color: #1d1d1f;
}

.field-value {
  color: #424245;
  font-weight: 500;
}

.hero-bullet-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 32px;
}

.hero-bullet-list li {
  font-size: 15px;
  color: #3a3a3c;
  line-height: 1.5;
  position: relative;
  padding-left: 16px;
}

.hero-bullet-list li::before {
  content: "•";
  position: absolute;
  left: 0;
  color: #0066cc;
  font-weight: bold;
}

.hero-actions {
  display: flex;
  gap: 12px;
  align-items: center;
}

.btn-hero-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  background: var(--color-primary);
  color: #ffffff;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius-pill);
  transition: var(--transition-smooth);
}

.btn-hero-primary:hover {
  background: var(--color-primary-hover);
  color: #ffffff;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 102, 204, 0.3);
}

.btn-hero-secondary {
  display: inline-flex;
  align-items: center;
  padding: 10px 20px;
  background: rgba(0, 0, 0, 0.04);
  color: #1d1d1f;
  font-size: 14px;
  font-weight: 500;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(0, 0, 0, 0.08);
  transition: var(--transition-smooth);
}

.btn-hero-secondary:hover {
  background: rgba(0, 0, 0, 0.08);
  color: #000;
}

.hero-photo-side {
  position: relative;
  width: 380px;
  flex-shrink: 0;
  display: flex;
  justify-content: center;
  align-items: center;
}

.profile-cutout-img {
  width: 100%;
  max-width: 420px;
  height: auto;
  object-fit: contain;
  display: block;
  position: relative;
  z-index: 2;
  margin-top: -10px;
  transform: scale(1.15);
  transform-origin: center center;
  filter: saturate(0.7) contrast(1.03) drop-shadow(0 12px 24px rgba(0, 0, 0, 0.12));
  -webkit-mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 75%, rgba(0,0,0,0) 98%);
  mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 75%, rgba(0,0,0,0) 98%);
}

@media (max-width: 868px) {
  .profile-hero-card {
    padding: 32px 24px 0 24px;
  }
  .hero-content {
    flex-direction: column-reverse;
    align-items: center;
    gap: 24px;
  }
  .hero-text-side {
    max-width: 100%;
    padding-bottom: 40px;
  }
  .hero-photo-side {
    width: 280px;
  }
}

/* Common Section Layout */
.section-container {
  max-width: 1140px; margin: 0 auto; padding: 90px 24px;
}

.section-container.light-bg {
  background-color: #ffffff; max-width: 100%;
}

.section-container.light-bg .section-header,
.section-container.light-bg .skills-matrix {
  max-width: 1140px; margin-left: auto; margin-right: auto;
}

.section-tag {
  font-size: 12px; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.1em; color: var(--color-primary); margin-bottom: 6px; display: block;
}

.section-title {
  font-size: 36px; letter-spacing: -0.03em; margin-bottom: 8px;
}

.section-desc {
  font-size: 16px; color: var(--color-muted); margin-bottom: 40px;
}

/* Timeline Cards */
.timeline-wrapper {
  display: flex; flex-direction: column; gap: 24px;
}

/* GPA Summary Box */
.gpa-summary-box {
  background: #ffffff; border-radius: var(--radius-lg); padding: 28px 36px;
  border: 1px solid rgba(0, 0, 0, 0.08); box-shadow: var(--shadow-subtle);
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 32px; gap: 24px; flex-wrap: wrap;
}

.gpa-item { display: flex; flex-direction: column; gap: 4px; }
.gpa-label { font-size: 12px; font-weight: 600; color: var(--color-muted); text-transform: uppercase; letter-spacing: 0.05em; }
.gpa-val { font-size: 32px; font-weight: 700; color: var(--color-primary); font-family: var(--font-display); line-height: 1; }
.gpa-max { font-size: 18px; font-weight: 500; color: var(--color-muted); }
.gpa-sub { font-size: 13px; color: #515154; font-weight: 500; }

.gpa-divider { width: 1px; height: 50px; background: var(--color-hairline); }

/* Course List Grid */
/* Grade Group Grid */
.grade-group-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 16px; margin-top: 18px;
}

.grade-group-card {
  background: var(--color-parchment); border-radius: var(--radius-md); padding: 18px;
  border: 1px solid rgba(0, 0, 0, 0.05); display: flex; flex-direction: column; gap: 10px;
  transition: var(--transition-smooth);
}

.grade-group-card:hover {
  background: #ffffff; border-color: rgba(0, 102, 204, 0.2); box-shadow: var(--shadow-subtle);
  transform: translateY(-2px);
}

.grade-group-header {
  display: flex; justify-content: space-between; align-items: center; padding-bottom: 8px;
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}

.grade-badge {
  font-size: 13px; font-weight: 700; padding: 4px 12px; border-radius: var(--radius-pill);
}

.grade-badge.ap { background: rgba(48,176,199,0.18); color: #007791; }
.grade-badge.a { background: rgba(0,102,204,0.14); color: var(--color-primary); }
.grade-badge.b { background: rgba(0,0,0,0.07); color: #3a3a3c; }
.grade-badge.s { background: rgba(52,199,89,0.18); color: #248a3d; }

.grade-score { font-size: 13px; font-weight: 600; color: var(--color-muted); }

.grade-course-list {
  list-style: none; display: flex; flex-direction: column; gap: 6px;
}

.grade-course-list li {
  font-size: 13px;
  color: #1d1d1f;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 6px;
  line-height: 1.45;
  padding: 2px 0;
}

.grade-course-list li::before {
  content: "•";
  color: var(--color-primary);
  font-weight: bold;
  flex-shrink: 0;
}

.grade-course-list li.clickable-course {
  cursor: pointer;
  border-radius: 6px;
  padding: 3px 6px;
  margin: 0 -6px;
  transition: var(--transition-smooth);
}

.grade-course-list li.clickable-course:hover {
  background: rgba(0, 102, 204, 0.05);
  color: var(--color-primary);
}

.course-info-btn {
  font-size: 10.5px;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 5px;
  background: rgba(0, 102, 204, 0.07);
  color: var(--color-primary);
  border: 1px solid rgba(0, 102, 204, 0.14);
  margin-left: auto;
  flex-shrink: 0;
  white-space: nowrap;
  transition: var(--transition-smooth);
}

.grade-course-list li.clickable-course:hover .course-info-btn {
  background: var(--color-primary);
  color: #ffffff;
  border-color: var(--color-primary);
}

.timeline-card {
  background: #ffffff; border-radius: var(--radius-lg);
  padding: 32px; border: 1px solid rgba(0, 0, 0, 0.06);
  box-shadow: var(--shadow-subtle); transition: var(--transition-smooth);
}

.timeline-card:hover {
  transform: translateY(-4px); box-shadow: var(--shadow-hover);
}

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

.timeline-period {
  font-size: 13px; font-weight: 600; color: var(--color-primary);
}

.timeline-badge {
  font-size: 11px; font-weight: 600; padding: 3px 10px;
  border-radius: var(--radius-pill); background: rgba(0, 102, 204, 0.1); color: var(--color-primary);
}

.timeline-badge.completed {
  background: var(--color-parchment); color: var(--color-muted);
}

.timeline-title { font-size: 24px; font-weight: 600; margin-bottom: 4px; }
.timeline-sub { font-size: 15px; color: var(--color-muted); margin-bottom: 14px; font-weight: 500; }
.timeline-body p { font-size: 15px; line-height: 1.6; color: #3a3a3c; }

.timeline-tags { display: flex; gap: 6px; flex-wrap: wrap; margin: 14px 0; }
.tag-sm {
  font-size: 11px; padding: 3px 9px; border-radius: var(--radius-xs);
  background: var(--color-parchment); color: #48484a; font-weight: 500;
}

.timeline-clubs {
  font-size: 13px; color: #515154; padding-top: 12px;
  border-top: 1px solid var(--color-divider); margin-top: 14px;
}

/* Dark Canvas Section (Projects & Exhibitions) */
.dark-section {
  background-color: var(--color-dark-canvas); color: #ffffff;
  padding: 90px 24px;
}

.dark-container { max-width: 1140px; margin: 0 auto; }

.section-tag-dark {
  font-size: 12px; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.1em; color: var(--color-primary-dark); margin-bottom: 6px;
}

.section-title-dark { font-size: 40px; letter-spacing: -0.03em; color: #ffffff; margin-bottom: 8px; }
.section-desc-dark { font-size: 16px; color: var(--color-dark-muted); margin-bottom: 40px; }

.dark-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(420px, 1fr)); gap: 28px;
}

.dark-card {
  background-color: var(--color-dark-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-dark-border);
  padding: 36px; display: flex; flex-direction: column;
  justify-content: space-between; cursor: pointer;
  transition: var(--transition-smooth);
}

.dark-card:hover {
  transform: translateY(-6px);
  border-color: var(--color-primary-dark);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.4);
}

.dark-card-badge {
  display: inline-block; padding: 4px 12px; border-radius: var(--radius-pill);
  font-size: 11px; font-weight: 600; color: var(--color-primary-dark);
  border: 1px solid rgba(41, 151, 255, 0.3); margin-bottom: 16px; align-self: flex-start;
}

.dark-card-title { font-size: 26px; font-weight: 600; color: #ffffff; margin-bottom: 6px; }
.dark-card-period { font-size: 13px; color: var(--color-dark-muted); margin-bottom: 16px; }
.dark-card-desc { font-size: 15px; line-height: 1.6; color: #d1d1d6; margin-bottom: 24px; }

.dark-card-tags { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 24px; }
.dark-card-tags span {
  font-size: 11px; padding: 4px 10px; border-radius: var(--radius-xs);
  background: var(--color-dark-card); color: #a1a1a6; border: 1px solid var(--color-dark-border);
}

.card-link-btn {
  font-size: 13px; font-weight: 600; color: var(--color-primary-dark);
  display: flex; align-items: center; gap: 6px; margin-top: auto;
}

/* Leadership Grid Layout - Symmetric 2x2 Grid */
.leadership-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.leadership-card {
  background: #ffffff;
  border-radius: var(--radius-lg);
  padding: 30px;
  border: 1px solid rgba(0, 0, 0, 0.08);
  box-shadow: var(--shadow-subtle);
  transition: var(--transition-smooth);
  display: flex;
  flex-direction: column;
  height: 100%;
}

.leadership-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  border-color: rgba(0, 102, 204, 0.2);
}

.leadership-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 18px;
}

.card-icon-wrap {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--color-parchment);
  border: 1px solid rgba(0, 0, 0, 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
}

.leadership-card-tags {
  display: flex;
  align-items: center;
  gap: 8px;
}

.status-tag {
  font-size: 11px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
}

.status-tag.active {
  background: rgba(0, 102, 204, 0.09);
  color: var(--color-primary);
  border: 1px solid rgba(0, 102, 204, 0.2);
}

.status-tag.completed {
  background: rgba(120, 120, 128, 0.08);
  color: #666668;
  border: 1px solid rgba(0, 0, 0, 0.06);
}

.card-date-tag {
  font-size: 12.5px;
  font-weight: 600;
  color: #6e6e73;
}

.leadership-card-title {
  font-size: 19px;
  font-weight: 700;
  color: var(--color-ink);
  margin-bottom: 10px;
  line-height: 1.35;
  letter-spacing: -0.015em;
}

.leadership-card-title .highlight {
  color: var(--color-primary);
  font-size: 15.5px;
  font-weight: 600;
}

.leadership-card-desc {
  font-size: 14.5px;
  color: #424245;
  line-height: 1.6;
  margin-top: auto;
}

@media (max-width: 768px) {
  .leadership-grid {
    grid-template-columns: 1fr;
  }
}

/* Technical Skills Matrix */
.skills-matrix {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 24px;
}

.skill-category-card {
  background: var(--color-parchment); border-radius: var(--radius-lg);
  padding: 32px; border: 1px solid var(--color-hairline);
}

.skill-category-card h3 { font-size: 20px; margin-bottom: 20px; }

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

.skill-tag {
  background: #ffffff; padding: 10px 16px; border-radius: var(--radius-pill);
  border: 1px solid rgba(0, 0, 0, 0.08); font-size: 14px; font-weight: 500;
  color: var(--color-ink); box-shadow: var(--shadow-subtle);
  transition: var(--transition-smooth);
}

.skill-tag:hover {
  border-color: var(--color-primary); color: var(--color-primary);
  transform: translateY(-2px); box-shadow: var(--shadow-hover);
}

/* Modal Drawer */
.modal-backdrop {
  position: fixed; top: 0; left: 0; width: 100vw; height: 100vh;
  background: rgba(0, 0, 0, 0.4); backdrop-filter: blur(10px);
  z-index: 2000; display: flex; justify-content: center; align-items: center;
  opacity: 0; pointer-events: none; transition: opacity 0.3s ease;
}

.modal-backdrop.open { opacity: 1; pointer-events: auto; }

.modal-sheet {
  background: #ffffff; width: 90%; max-width: 720px; max-height: 85vh;
  border-radius: var(--radius-lg); box-shadow: var(--shadow-modal);
  overflow-y: auto; position: relative; transform: translateY(20px) scale(0.97);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-backdrop.open .modal-sheet { transform: translateY(0) scale(1); }

.modal-close-btn {
  position: absolute; top: 20px; right: 20px; width: 32px; height: 32px;
  border-radius: 50%; background: var(--color-parchment); border: none;
  display: flex; align-items: center; justify-content: center; cursor: pointer;
}

.modal-body { padding: 40px; }

/* Footer */
footer {
  background: var(--color-parchment); border-top: 1px solid var(--color-hairline);
  padding: 40px 24px; text-align: center; font-size: 13px; color: var(--color-muted);
}

.footer-container { max-width: 1140px; margin: 0 auto; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 16px; }

@media (max-width: 768px) {
  .hero-container { flex-direction: column-reverse; text-align: center; }
  .hero-title { font-size: 32px; }
  .dark-grid { grid-template-columns: 1fr; }
  .nav-menu { display: none; }
  .footer-container { flex-direction: column; text-align: center; }
}