/* =============================================================================
   IEEE ITSS Korea Chapter — Stylesheet
   Brand colors: IEEE Blue #00629B, ITSS Red #BA0C2F
   Fonts: Open Sans (Latin), Noto Sans KR (Korean)
   ============================================================================= */

/* --- CSS Custom Properties --- */
:root {
  --ieee-blue: #00629B;
  --ieee-blue-dark: #004165;
  --ieee-blue-light: #e8f4fa;
  --itss-red: #BA0C2F;
  --itss-red-dark: #8a0923;

  --text-primary: #1a1a1a;
  --text-secondary: #4a4a4a;
  --text-muted: #717171;
  --bg-white: #ffffff;
  --bg-light: #f7f9fb;
  --bg-alt: #eef3f7;
  --border-color: #d4dce4;

  --font-sans: 'Open Sans', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-size-base: 16px;
  --line-height: 1.65;

  --container-max: 1280px;
  --spacing: 1.5rem;
  --radius: 6px;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.12);
}

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

/* --- Base --- */
html { font-size: var(--font-size-base); scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  line-height: var(--line-height);
  color: var(--text-primary);
  background: var(--bg-white);
  -webkit-font-smoothing: antialiased;
}

a { color: var(--ieee-blue); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--ieee-blue-dark); text-decoration: underline; }
img { max-width: 100%; height: auto; display: block; }
ul, ol { padding-left: 1.5em; }

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing);
}

/* =============================================================================
   IEEE Top Bar
   ============================================================================= */
.ieee-topbar {
  background: var(--ieee-blue-dark);
  color: #fff;
  font-size: 0.75rem;
  padding: 0.35rem 0;
}
.ieee-topbar-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.ieee-topbar-links { display: flex; gap: 1rem; flex-wrap: wrap; }
.ieee-topbar a { color: rgba(255,255,255,0.85); }
.ieee-topbar a:hover { color: #fff; text-decoration: underline; }
.ieee-topbar-actions a {
  background: var(--itss-red);
  color: #fff;
  padding: 0.2rem 0.7rem;
  border-radius: 3px;
  font-weight: 600;
}
.ieee-topbar-actions a:hover { background: var(--itss-red-dark); text-decoration: none; }

/* =============================================================================
   Site Header
   ============================================================================= */
.site-header {
  background: var(--ieee-blue);
  color: #fff;
  padding: 1rem 0;
}
.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.site-brand {
  display: flex;
  align-items: center;
  gap: 1rem;
}
.site-logo {
  height: 56px;
  width: auto;
  border-radius: 50%;
  background: #fff;
  padding: 2px;
}
.site-title-link { color: #fff; }
.site-title-link:hover { color: #fff; text-decoration: none; }
.site-title {
  display: block;
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}
.site-subtitle {
  display: block;
  font-size: 0.95rem;
  font-weight: 400;
  opacity: 0.9;
}
.ieee-master-brand { flex-shrink: 0; }
.ieee-logo { height: 33px; width: auto; min-width: 100px; }

/* =============================================================================
   Navigation
   ============================================================================= */
.site-nav {
  background: var(--ieee-blue-dark);
  padding: 0;
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.nav-menu {
  display: flex;
  list-style: none;
  padding: 0;
  margin: 0;
  gap: 0;
}
.nav-item {}
.nav-link {
  display: block;
  color: rgba(255,255,255,0.9);
  padding: 0.75rem 1rem;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.2s;
}
.nav-link:hover {
  background: rgba(255,255,255,0.1);
  color: #fff;
  text-decoration: none;
}

/* Language switcher */
.lang-switch { flex-shrink: 0; }
.lang-link {
  display: inline-block;
  color: #fff;
  border: 1px solid rgba(255,255,255,0.5);
  padding: 0.35rem 0.8rem;
  border-radius: var(--radius);
  font-size: 0.8rem;
  font-weight: 600;
  transition: all 0.2s;
}
.lang-link:hover {
  background: rgba(255,255,255,0.15);
  border-color: #fff;
  text-decoration: none;
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}
.nav-toggle-icon,
.nav-toggle-icon::before,
.nav-toggle-icon::after {
  display: block;
  width: 24px;
  height: 2px;
  background: #fff;
  transition: transform 0.3s;
}
.nav-toggle-icon { position: relative; }
.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: '';
  position: absolute;
  left: 0;
}
.nav-toggle-icon::before { top: -7px; }
.nav-toggle-icon::after  { top: 7px; }

/* =============================================================================
   Hero Section
   ============================================================================= */
.hero {
  background: linear-gradient(135deg, var(--ieee-blue) 0%, var(--ieee-blue-dark) 100%);
  color: #fff;
  padding: 4rem 0 3.5rem;
  text-align: center;
}
.hero h1 {
  font-size: 2.2rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 1rem;
}
.hero-description {
  font-size: 1.15rem;
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto;
}

/* =============================================================================
   Sections
   ============================================================================= */
.section {
  padding: 3rem 0;
}
.section--alt {
  background: var(--bg-light);
}
.section h2 {
  font-size: 1.6rem;
  color: var(--ieee-blue);
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 3px solid var(--itss-red);
  display: inline-block;
}
.section-header {
  margin-bottom: 2rem;
}
.section-header h1 {
  font-size: 2rem;
  color: var(--ieee-blue);
  border-bottom: 3px solid var(--itss-red);
  display: inline-block;
  padding-bottom: 0.3rem;
}

/* =============================================================================
   Card Grid
   ============================================================================= */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: 1.5rem;
}
.card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: box-shadow 0.2s, transform 0.2s;
  overflow: hidden;
}
.card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}
.card-body { padding: 1.5rem; }
.card-date {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.3rem;
}
.card-title {
  font-size: 1.15rem;
  margin-bottom: 0.5rem;
}
.card-title a { color: var(--text-primary); }
.card-title a:hover { color: var(--ieee-blue); }
.card-link {
  display: inline-block;
  margin-top: 0.5rem;
  font-weight: 600;
  font-size: 0.9rem;
}

/* =============================================================================
   Community Links
   ============================================================================= */
.community-links {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1rem;
}
.community-card {
  display: block;
  background: var(--bg-white);
  border: 2px solid var(--border-color);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-align: center;
  transition: all 0.2s;
}
.community-card:hover {
  border-color: var(--ieee-blue);
  box-shadow: var(--shadow);
  text-decoration: none;
}
.community-card strong {
  display: block;
  font-size: 1.1rem;
  color: var(--ieee-blue);
  margin-bottom: 0.3rem;
}
.community-card span {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* =============================================================================
   Content Pages (single)
   ============================================================================= */
.content-single { max-width: 800px; }
.content-header { margin-bottom: 2rem; }
.content-header h1 {
  font-size: 2rem;
  color: var(--ieee-blue);
}
.content-date {
  display: block;
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
}
.content-subtitle {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
}
.content-body h2 { font-size: 1.4rem; margin: 2rem 0 0.8rem; }
.content-body h3 { font-size: 1.2rem; margin: 1.5rem 0 0.6rem; }
.content-body p { margin-bottom: 1rem; }
.content-body ul, .content-body ol { margin-bottom: 1rem; }
.content-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
}
.content-body th, .content-body td {
  border: 1px solid var(--border-color);
  padding: 0.6rem 1rem;
  text-align: left;
}
.content-body th { background: var(--bg-light); font-weight: 600; }

.event-meta {
  background: var(--bg-light);
  border-left: 4px solid var(--itss-red);
  padding: 1rem 1.5rem;
  margin-bottom: 2rem;
  border-radius: 0 var(--radius) var(--radius) 0;
}
.meta-item { margin-bottom: 0.3rem; }
.meta-item:last-child { margin-bottom: 0; }

.content-translations { margin-top: 2rem; }
.content-nav { margin-top: 2rem; padding-top: 1.5rem; border-top: 1px solid var(--border-color); }

/* =============================================================================
   Leadership Page — People Grid
   ============================================================================= */
.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}
.person-card {
  text-align: center;
  padding: 1.5rem 1rem;
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.person-card img {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 1rem;
  border: 3px solid var(--ieee-blue-light);
}
.person-card h3 { font-size: 1.05rem; margin-bottom: 0.2rem; }
.person-card .role { color: var(--itss-red); font-weight: 600; font-size: 0.9rem; }
.person-card .affiliation { color: var(--text-muted); font-size: 0.85rem; }

/* =============================================================================
   Buttons
   ============================================================================= */
.btn {
  display: inline-block;
  padding: 0.6rem 1.4rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.9rem;
  text-decoration: none;
  transition: all 0.2s;
  cursor: pointer;
  border: 2px solid transparent;
}
.btn--primary {
  background: var(--ieee-blue);
  color: #fff;
  border-color: var(--ieee-blue);
}
.btn--primary:hover {
  background: var(--ieee-blue-dark);
  border-color: var(--ieee-blue-dark);
  color: #fff;
  text-decoration: none;
}
.btn--outline {
  background: transparent;
  color: var(--ieee-blue);
  border-color: var(--ieee-blue);
}
.btn--outline:hover {
  background: var(--ieee-blue);
  color: #fff;
  text-decoration: none;
}

/* =============================================================================
   Empty state
   ============================================================================= */
.empty-message {
  color: var(--text-muted);
  font-style: italic;
  padding: 2rem;
  text-align: center;
  background: var(--bg-alt);
  border-radius: var(--radius);
}

/* =============================================================================
   Footer
   ============================================================================= */
.site-footer {
  background: #1a2a3a;
  color: rgba(255,255,255,0.85);
  padding: 2.5rem 0 0;
  margin-top: 3rem;
  font-size: 0.9rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 2rem;
  padding-bottom: 2rem;
}
.footer-col h3 {
  color: #fff;
  font-size: 1rem;
  margin-bottom: 0.8rem;
}
.footer-col ul { list-style: none; padding: 0; }
.footer-col li { margin-bottom: 0.4rem; }
.footer-col a { color: rgba(255,255,255,0.75); }
.footer-col a:hover { color: #fff; }

.footer-ieee {
  border-top: 1px solid rgba(255,255,255,0.15);
  padding: 1.2rem 0;
  text-align: center;
}
.footer-ieee-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  margin-bottom: 0.8rem;
}
.footer-ieee-links a {
  color: rgba(255,255,255,0.6);
  font-size: 0.8rem;
}
.footer-ieee-links a:hover { color: #fff; }
.footer-copyright {
  color: rgba(255,255,255,0.5);
  font-size: 0.8rem;
}
.footer-build {
  color: rgba(255,255,255,0.3);
  font-size: 0.7rem;
  font-family: monospace;
  margin-top: 0.3rem;
}

/* =============================================================================
   Responsive
   ============================================================================= */
@media (max-width: 768px) {
  .ieee-topbar-links { display: none; }

  .header-inner { flex-direction: column; gap: 0.5rem; text-align: center; }
  .site-brand { flex-direction: column; gap: 0.5rem; }

  .nav-toggle { display: block; }
  .nav-menu {
    display: none;
    flex-direction: column;
    width: 100%;
    background: var(--ieee-blue-dark);
  }
  .nav-menu--open { display: flex; }
  .nav-inner { flex-wrap: wrap; }
  .nav-link { padding: 0.8rem 1rem; border-top: 1px solid rgba(255,255,255,0.1); }
  .lang-switch { padding: 0.5rem 0; }

  .hero { padding: 2.5rem 0 2rem; }
  .hero h1 { font-size: 1.6rem; }

  .card-grid { grid-template-columns: 1fr; }
  .community-links { grid-template-columns: 1fr; }
  .people-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); }

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