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

:root {
  --color-primary: #0f172a;
  --color-primary-light: #1e293b;
  --color-accent: #6366f1;
  --color-accent-light: #818cf8;
  --color-accent-glow: rgba(99,102,241,0.25);
  --color-bg: #0f172a;
  --color-surface: rgba(255,255,255,0.05);
  --color-white: #ffffff;
  --color-text: #e2e8f0;
  --color-text-light: #94a3b8;
  --color-text-muted: #64748b;
  --color-border: rgba(255,255,255,0.08);
  --color-success: #34d399;
  --color-warning: #fbbf24;
  --color-error: #f87171;

  /* Glass */
  --glass-bg: rgba(255,255,255,0.06);
  --glass-bg-strong: rgba(255,255,255,0.1);
  --glass-border: rgba(255,255,255,0.12);
  --glass-blur: 20px;
  --glass-shadow: 0 8px 32px rgba(0,0,0,0.3);

  --font-main: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-display: 'Playfair Display', Georgia, 'Times New Roman', serif;
  --font-logo: 'Cormorant Garamond', Georgia, 'Times New Roman', serif;
  --max-width: 1100px;
  --radius: 16px;
  --radius-sm: 10px;
  --transition: 0.3s ease;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-main);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Animated gradient background */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background:
    radial-gradient(ellipse 80% 60% at 10% 20%, rgba(99,102,241,0.15) 0%, transparent 60%),
    radial-gradient(ellipse 60% 50% at 90% 80%, rgba(139,92,246,0.12) 0%, transparent 60%),
    radial-gradient(ellipse 50% 40% at 50% 50%, rgba(59,130,246,0.08) 0%, transparent 60%);
  z-index: -1;
  animation: bgShift 20s ease-in-out infinite alternate;
}

@keyframes bgShift {
  0% { opacity: 1; }
  50% { opacity: 0.7; }
  100% { opacity: 1; }
}

a {
  color: var(--color-accent-light);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-white);
}

img {
  max-width: 100%;
  display: block;
}

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

.text-center {
  text-align: center;
}

/* ===== Glass Utility ===== */
.glass {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  box-shadow: var(--glass-shadow);
}

/* ===== Header ===== */
.header {
  background: rgba(15,23,42,0.7);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.logo {
  font-family: var(--font-logo);
  font-size: 1.8rem;
  font-weight: 600;
  color: #fef9e7;
  letter-spacing: 0.02em;
}

.logo:hover {
  color: var(--color-white);
}

.nav {
  display: flex;
  gap: 2rem;
}

.nav-link {
  font-family: 'Inter', var(--font-main);
  font-size: 1.4rem;
  font-weight: 500;
  color: var(--color-text-light);
  padding: 0.4rem 0;
  border-bottom: 2px solid transparent;
  transition: all var(--transition);
  letter-spacing: -0.01em;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-white);
  border-bottom-color: var(--color-accent);
}

.lang-toggle {
  background: rgba(99,102,241,0.15);
  color: var(--color-accent-light);
  border: 1px solid rgba(99,102,241,0.3);
  padding: 0.35rem 0.85rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}

.lang-toggle:hover {
  background: var(--color-accent);
  color: var(--color-white);
  border-color: var(--color-accent);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--color-white);
  cursor: pointer;
}

/* ===== Hero ===== */
.hero {
  position: relative;
  padding: 8rem 0 6rem;
  text-align: center;
  overflow: hidden;
}

/* Hero with background image */
.hero-bg {
  padding: 0;
  min-height: 520px;
  display: flex;
  align-items: flex-end;
}

.hero-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background: url('../images/hero-bg.jpg') center center / cover no-repeat;
  filter: brightness(1.25) contrast(1.1);
  z-index: -1;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(15,23,42,0.0) 0%,
    rgba(15,23,42,0.05) 35%,
    rgba(15,23,42,0.55) 65%,
    rgba(15,23,42,0.8) 100%
  );
  z-index: 0;
}

.hero-spacer {
  flex: 1;
}

.hero::before {
  display: none;
}

.hero-content {
  position: relative;
  z-index: 2;
  width: 100%;
  padding-bottom: 2.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hero-subtitle {
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-accent-light);
  margin-bottom: 1rem;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: 3.25rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 2rem;
  letter-spacing: -0.03em;
  color: var(--color-white);
  background: linear-gradient(135deg, #fff 0%, #c7d2fe 50%, #a5b4fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Hero Details (text lines) */
.hero-details {
  margin-bottom: 1.8rem;
  text-align: center;
}

.hero-detail-line {
  font-family: var(--font-display);
  font-size: 1.7rem;
  font-weight: 600;
  color: var(--color-white);
  margin: 0 0 0.5rem;
  letter-spacing: 0.02em;
  text-shadow: 0 2px 12px rgba(0,0,0,0.6);
  line-height: 1.4;
}

.hero-detail-sub {
  font-family: var(--font-main);
  font-size: 1.02rem;
  font-weight: 400;
  color: rgba(255,255,255,0.75);
  text-shadow: 0 1px 4px rgba(0,0,0,0.4);
}

.hero-cta-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.hero-cta-group .btn,
.cta-btn-group .btn {
  min-width: 230px;
  text-align: center;
}

.hero-cta {
  font-size: 0.95rem;
}

.cta-btn-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 1.5rem;
}

/* ===== Page Hero ===== */
.page-hero {
  position: relative;
  padding: 5rem 0 3.5rem;
  text-align: center;
  overflow: hidden;
}

.page-hero::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(99,102,241,0.15) 0%, transparent 70%);
  transform: translate(-50%, -50%);
}

.page-hero .container {
  position: relative;
  z-index: 1;
}

.page-hero-title {
  font-family: var(--font-heading);
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
  color: var(--color-white);
  background: linear-gradient(135deg, #fff 0%, #c7d2fe 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.page-hero-subtitle {
  font-size: 1.05rem;
  color: var(--color-text-light);
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 0.8rem 2.25rem;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  text-align: center;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all var(--transition);
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-white);
  border-color: var(--color-accent);
  box-shadow: 0 4px 20px var(--color-accent-glow);
}

.btn-primary:hover {
  background: var(--color-accent-light);
  border-color: var(--color-accent-light);
  color: var(--color-white);
  box-shadow: 0 6px 30px rgba(99,102,241,0.4);
  transform: translateY(-1px);
}

.btn-outline {
  background: transparent;
  color: var(--color-accent-light);
  border-color: rgba(99,102,241,0.4);
}

.btn-outline:hover {
  background: rgba(99,102,241,0.1);
  color: var(--color-white);
  border-color: var(--color-accent);
}

/* CUK Blue Button (Gradient) */
.btn-cuk {
  background: linear-gradient(135deg, #1a3a6b, #2756a3);
  color: var(--color-white);
  border: none;
  box-shadow: 0 4px 20px rgba(26,58,107,0.35);
}

.btn-cuk:hover {
  background: linear-gradient(135deg, #244d8a, #3268b7);
  color: var(--color-white);
  box-shadow: 0 6px 30px rgba(26,58,107,0.5);
  transform: translateY(-1px);
}

/* Conference Open Button (Teal Gradient) */
.btn-conf {
  background: linear-gradient(135deg, #0d9488, #2dd4bf);
  color: var(--color-white);
  border: none;
  box-shadow: 0 4px 20px rgba(13,148,136,0.3);
}

.btn-conf:hover {
  background: linear-gradient(135deg, #0f766e, #14b8a6);
  color: var(--color-white);
  box-shadow: 0 6px 30px rgba(13,148,136,0.45);
  transform: translateY(-1px);
}

/* Button sub-text (second line) */
.btn-sub {
  display: block;
  font-size: 0.72rem;
  font-weight: 400;
  opacity: 0.85;
  margin-top: 0.2rem;
  letter-spacing: 0.03em;
}

.btn-full {
  width: 100%;
  padding: 1rem;
  font-size: 1.05rem;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* ===== Sections ===== */
.section {
  padding: 5rem 0;
}

.section-title {
  font-family: var(--font-heading);
  font-size: 1.85rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 1rem;
  text-align: center;
}

.section-desc {
  max-width: 720px;
  margin: 0 auto 2.5rem;
  text-align: center;
  color: var(--color-text-light);
  line-height: 1.8;
}

/* ===== Card Grid ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.card {
  position: relative;
  border-radius: 4px;
  padding: 0;
  transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  overflow: hidden;
  min-height: 380px;
  display: flex;
  border: 1px solid rgba(255,255,255,0.08);
}

.card-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  transition: transform 0.6s ease;
}

.card--day1 .card-bg {
  background: linear-gradient(135deg, #1a1a3e 0%, #2d1b69 50%, #1e293b 100%);
}

.card--day2 .card-bg {
  background: linear-gradient(135deg, #1b2a3e 0%, #164e63 50%, #1e293b 100%);
}

.card--day3 .card-bg {
  background: linear-gradient(135deg, #2a1b3e 0%, #4c1d6e 50%, #1e293b 100%);
}

.card:hover .card-bg {
  transform: scale(1.05);
}

.card-inner {
  position: relative;
  z-index: 1;
  padding: 2.2rem 1.8rem;
  display: flex;
  flex-direction: column;
  width: 100%;
}

.card-number {
  font-family: var(--font-display);
  font-size: 2.4rem;
  font-weight: 700;
  color: rgba(255,255,255,0.08);
  position: absolute;
  top: 1rem;
  right: 1.2rem;
  line-height: 1;
  letter-spacing: -0.03em;
}

.card:hover .card-number {
  color: rgba(255,255,255,0.12);
}

.card-badge {
  display: inline-block;
  background: rgba(255,255,255,0.1);
  color: var(--color-accent-light);
  padding: 0.25rem 0.75rem;
  border-radius: 2px;
  font-family: 'Inter', var(--font-main);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 1.2rem;
  width: fit-content;
  border: 1px solid rgba(255,255,255,0.15);
}

.card-title {
  font-family: var(--font-display);
  font-size: 1.55rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 0.35rem;
  line-height: 1.2;
  letter-spacing: -0.01em;
}

.card-subtitle {
  font-size: 0.82rem;
  color: rgba(255,255,255,0.45);
  margin-bottom: 0;
  font-weight: 400;
}

.card-divider {
  width: 32px;
  height: 2px;
  background: var(--color-accent);
  margin: 1rem 0;
  opacity: 0.6;
  transition: width 0.3s ease, opacity 0.3s ease;
}

.card:hover .card-divider {
  width: 56px;
  opacity: 1;
}

.card-time {
  font-family: 'Inter', var(--font-main);
  font-size: 0.78rem;
  color: var(--color-accent-light);
  font-weight: 600;
  margin-bottom: 0.6rem;
  letter-spacing: 0.03em;
}

.card-desc {
  font-size: 0.88rem;
  color: rgba(255,255,255,0.6);
  line-height: 1.65;
}

.card-tag {
  display: inline-block;
  background: rgba(251,191,36,0.12);
  color: var(--color-warning);
  padding: 0.2rem 0.6rem;
  border-radius: 2px;
  font-size: 0.72rem;
  font-weight: 600;
  margin-top: 0.75rem;
  border: 1px solid rgba(251,191,36,0.2);
  width: fit-content;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 20px 50px rgba(0,0,0,0.4);
  border-color: rgba(255,255,255,0.15);
}

/* ===== CTA Section ===== */
.cta-section {
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.cta-title {
  font-family: var(--font-heading);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 0.75rem;
}

.cta-desc {
  color: var(--color-text-light);
  margin-bottom: 1.75rem;
  font-size: 1rem;
}

/* ===== Program Page ===== */
.program-day {
  border-bottom: 1px solid var(--color-border);
}

.program-day:last-of-type {
  border-bottom: none;
}

.day-header {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.day-badge {
  background: rgba(99,102,241,0.2);
  color: var(--color-accent-light);
  padding: 0.45rem 1.1rem;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  white-space: nowrap;
  border: 1px solid rgba(99,102,241,0.3);
}

.day-badge-accent {
  background: rgba(251,191,36,0.15);
  color: var(--color-warning);
  border-color: rgba(251,191,36,0.3);
}

.day-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-white);
}

.day-subtitle {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.day-time {
  margin-left: auto;
  font-size: 0.9rem;
  color: var(--color-accent-light);
  font-weight: 600;
  white-space: nowrap;
}

.day-content {
  padding-left: 0.5rem;
}

.day-desc {
  color: var(--color-text-light);
  margin-bottom: 1.5rem;
  line-height: 1.8;
}

.day-notice {
  background: rgba(251,191,36,0.08);
  border-left: 3px solid var(--color-warning);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-bottom: 1.5rem;
}

.day-notice strong {
  display: block;
  margin-bottom: 0.25rem;
  color: var(--color-warning);
}

.day-notice p {
  font-size: 0.9rem;
  color: var(--color-text-light);
}

/* Visit Cards */
.visit-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.visit-card {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 1.25rem;
  transition: all var(--transition);
}

.visit-card:hover {
  background: var(--glass-bg-strong);
  border-color: rgba(99,102,241,0.2);
}

.visit-card h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 0.5rem;
}

.visit-card p {
  font-size: 0.875rem;
  color: var(--color-text-light);
}

/* Timeline */
.timeline {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  overflow: hidden;
}

.timeline-item {
  display: flex;
  align-items: center;
  padding: 0.9rem 1.5rem;
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition);
}

.timeline-item:last-child {
  border-bottom: none;
}

.timeline-item:hover {
  background: rgba(255,255,255,0.03);
}

.timeline-item--break {
  background: rgba(255,255,255,0.02);
}

.timeline-item--break .timeline-label {
  color: var(--color-text-light);
  font-style: italic;
}

.timeline-time {
  min-width: 140px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-accent-light);
}

.timeline-label {
  font-size: 0.925rem;
  color: var(--color-text);
}

/* Timeline 4-column (time / title / speaker / affiliation) */
.timeline-title {
  flex: 1;
  font-size: 0.925rem;
  color: var(--color-text);
}

.timeline-speaker {
  min-width: 150px;
  font-size: 0.85rem;
  color: var(--color-accent-light);
  text-align: right;
  font-weight: 500;
}

.timeline-affil {
  min-width: 180px;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  text-align: right;
  line-height: 1.4;
}

.timeline-item--break .timeline-title {
  color: var(--color-text-light);
  font-style: italic;
}

.timeline-item--break .timeline-speaker,
.timeline-item--break .timeline-affil {
  color: var(--color-text-muted);
  font-style: italic;
}

/* Day 3: program column (time / program / key content / presenters) */
.timeline-program {
  min-width: 160px;
  max-width: 160px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text);
  line-height: 1.4;
}

.timeline-item--break .timeline-program {
  color: var(--color-text-light);
  font-style: italic;
}

/* Timeline header row */
.timeline-header {
  display: flex;
  align-items: center;
  padding: 0.6rem 1.5rem;
  border-bottom: 1px solid rgba(255,255,255,0.15);
  background: rgba(255,255,255,0.04);
}

.timeline-header span {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-text-light);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ===== Registration Form ===== */
.reg-form {
  max-width: 640px;
  margin: 0 auto;
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 2.5rem;
  box-shadow: var(--glass-shadow);
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-label {
  display: block;
  font-size: 0.925rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.required {
  color: var(--color-error);
  margin-left: 2px;
}

.form-hint {
  font-size: 0.8rem;
  font-weight: 400;
  color: var(--color-text-muted);
  margin-left: 0.25rem;
}

.form-input {
  width: 100%;
  padding: 0.8rem 1rem;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-family: var(--font-main);
  color: var(--color-white);
  background: rgba(255,255,255,0.05);
  transition: all var(--transition);
}

.form-input::placeholder {
  color: var(--color-text-muted);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
  background: rgba(255,255,255,0.08);
}

.form-input.error {
  border-color: var(--color-error);
  box-shadow: 0 0 0 3px rgba(248,113,113,0.15);
}

.form-select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2394a3b8' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 2.5rem;
}

.form-select option {
  background: var(--color-primary);
  color: var(--color-text);
}

.form-error {
  display: block;
  font-size: 0.8rem;
  color: var(--color-error);
  margin-top: 0.35rem;
  min-height: 1.2em;
}

/* Checkbox Group */
.checkbox-group {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.checkbox-label {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  cursor: pointer;
  padding: 1rem;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  font-size: 0.925rem;
}

.checkbox-label:hover {
  border-color: rgba(99,102,241,0.3);
  background: rgba(99,102,241,0.05);
}

.checkbox-input {
  display: none;
}

.checkbox-custom {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  border: 2px solid var(--color-text-muted);
  border-radius: 5px;
  margin-top: 2px;
  transition: all var(--transition);
  position: relative;
}

.checkbox-input:checked + .checkbox-custom {
  background: var(--color-accent);
  border-color: var(--color-accent);
  box-shadow: 0 0 8px var(--color-accent-glow);
}

.checkbox-input:checked + .checkbox-custom::after {
  content: '';
  position: absolute;
  top: 2px;
  left: 5px;
  width: 5px;
  height: 10px;
  border: 2px solid white;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.checkbox-input:checked ~ span {
  color: var(--color-white);
}

.tag-limited {
  display: inline-block;
  background: rgba(251,191,36,0.15);
  color: var(--color-warning);
  padding: 0.1rem 0.55rem;
  border-radius: 10px;
  font-size: 0.7rem;
  font-weight: 600;
  margin-left: 0.5rem;
  vertical-align: middle;
  border: 1px solid rgba(251,191,36,0.25);
}

/* Radio buttons */
.radio-group {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.radio-label {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  cursor: pointer;
  padding: 1rem;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  font-size: 0.925rem;
}

.radio-label:hover {
  border-color: rgba(99,102,241,0.3);
  background: rgba(99,102,241,0.05);
}

.radio-input {
  display: none;
}

.radio-custom {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  border: 2px solid var(--color-text-muted);
  border-radius: 50%;
  transition: all var(--transition);
  position: relative;
}

.radio-input:checked + .radio-custom {
  border-color: var(--color-accent);
  box-shadow: 0 0 8px var(--color-accent-glow);
}

.radio-input:checked + .radio-custom::after {
  content: '';
  position: absolute;
  top: 3px;
  left: 3px;
  width: 10px;
  height: 10px;
  background: var(--color-accent);
  border-radius: 50%;
}

.radio-input:checked ~ span {
  color: var(--color-white);
}

.day2-notice {
  background: rgba(251,191,36,0.08);
  border-left: 3px solid var(--color-warning);
  padding: 0.75rem 1rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-left: 2rem;
  font-size: 0.875rem;
}

.day2-notice p {
  color: var(--color-warning);
}

/* Form Actions */
.form-actions {
  margin-top: 2rem;
}

/* Success Message */
.success-message {
  max-width: 640px;
  margin: 0 auto;
  text-align: center;
  padding: 3rem 2rem;
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  box-shadow: var(--glass-shadow);
}

.success-icon {
  width: 72px;
  height: 72px;
  background: rgba(52,211,153,0.15);
  color: var(--color-success);
  border: 2px solid rgba(52,211,153,0.3);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  margin: 0 auto 1.5rem;
}

.success-message h2 {
  font-size: 1.5rem;
  color: var(--color-white);
  margin-bottom: 0.75rem;
}

.success-message p {
  color: var(--color-text-light);
  margin-bottom: 1.5rem;
}

/* ===== Footer ===== */
.footer {
  background: rgba(15,23,42,0.8);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  padding: 2.5rem 0;
  text-align: center;
  overflow: hidden;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-title {
  font-weight: 600;
  color: var(--color-text-light);
  font-size: 0.95rem;
}

.footer-contact {
  font-size: 0.85rem;
}

.footer-copy {
  font-size: 0.8rem;
  opacity: 0.5;
}

.footer-orgs {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  margin: 0.5rem 0;
}

.footer-orgs p {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin: 0;
}

.footer-logos {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 2.5rem;
  margin: 1.2rem -999px;
  padding: 0.5rem 999px;
  flex-wrap: wrap;
  background: rgba(255,255,255,0.92);
}

.footer-logo {
  height: 50px;
  width: auto;
  max-width: 220px;
  object-fit: contain;
  opacity: 1;
}

.footer-logo--phi {
  height: 115px;
}

.footer-logo--epic {
  height: 57px;
}

.footer-logo--nrf {
  height: 74px;
}

/* ===== Loading Spinner ===== */
.spinner {
  display: inline-block;
  width: 18px;
  height: 18px;
  border: 2px solid rgba(255,255,255,0.2);
  border-radius: 50%;
  border-top-color: white;
  animation: spin 0.6s linear infinite;
  vertical-align: middle;
  margin-right: 0.5rem;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: rgba(15,23,42,0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--color-border);
    gap: 0.5rem;
    box-shadow: var(--glass-shadow);
  }

  .nav.open {
    display: flex;
  }

  .mobile-menu-btn {
    display: block;
  }

  .lang-toggle {
    margin-right: 0.75rem;
  }

  .hero {
    padding: 5rem 0 4rem;
  }

  .hero-bg {
    min-height: 400px;
  }

  .hero-detail-line {
    font-size: 1.25rem;
  }

  .hero-detail-sub {
    font-size: 0.82rem;
  }

  .page-hero {
    padding: 3.5rem 0 2.5rem;
  }

  .page-hero-title {
    font-size: 1.75rem;
  }

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

  .visit-cards {
    grid-template-columns: 1fr;
  }

  .day-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  .day-time {
    margin-left: 0;
  }

  .timeline-header {
    display: none;
  }

  .timeline-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.25rem;
  }

  .timeline-time {
    min-width: auto;
  }

  .timeline-speaker,
  .timeline-affil {
    min-width: auto;
    text-align: left;
  }

  .timeline-program {
    min-width: auto;
    max-width: none;
  }

  .reg-form {
    padding: 1.5rem;
  }

  .section {
    padding: 3.5rem 0;
  }
}

@media (max-width: 480px) {
  .hero-bg {
    min-height: 350px;
  }

  .day-title {
    font-size: 1.2rem;
  }
}

/* Visual Highlights — 신규 index.html 섹션 (program_at_a_glance / Organization_Team) */
.highlights .container {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}
.day-image { text-align: center; }
.day-image img {
  display: block;
  width: 100%;
  max-width: 960px;
  height: auto;
  margin: 0 auto;
  border-radius: 12px;
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.1);
}