/* ==========================================================================
   강석수학 (KANG MATH) - 공식 홈페이지 프리미엄 스타일시트
   kangmath.com / 강석수학.com
   ========================================================================== */

:root {
  /* Color Palette */
  --bg-dark: #070a12;
  --bg-card: rgba(15, 23, 42, 0.75);
  --bg-card-hover: rgba(26, 38, 66, 0.85);
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-glow: rgba(59, 130, 246, 0.35);
  
  --primary-blue: #3b82f6;
  --primary-glow: rgba(59, 130, 246, 0.5);
  --secondary-cyan: #06b6d4;
  --accent-gold: #f59e0b;
  --gold-glow: rgba(245, 158, 11, 0.4);
  
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-light: #cbd5e1;
  
  --yt-red: #ef4444;
  --naver-green: #03c75a;
  
  /* Fonts */
  --font-base: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
  --font-heading: 'Pretendard', 'Outfit', 'Plus Jakarta Sans', sans-serif;
  --font-num: 'Outfit', 'Plus Jakarta Sans', sans-serif;
  
  /* Transitions & Shadows */
  --transition-smooth: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  --shadow-card: 0 10px 30px -10px rgba(0, 0, 0, 0.6);
  --shadow-glow: 0 0 25px rgba(59, 130, 246, 0.35);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  color-scheme: dark;
}

body {
  background-color: var(--bg-dark);
  color: var(--text-main);
  font-family: var(--font-base);
  line-height: 1.65;
  overflow-x: hidden;
  position: relative;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Background Math Canvas */
#math-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
  pointer-events: none;
  opacity: 0.6;
}

/* Container */
.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Typography Utilities */
h1, h2, h3, h4, h5 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.3;
  color: #ffffff;
}

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

ul {
  list-style: none;
}

.gradient-text {
  background: linear-gradient(135deg, #60a5fa 0%, #38bdf8 50%, #22d3ee 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.highlight-gold {
  color: #fbbf24;
  text-shadow: 0 0 20px rgba(251, 191, 36, 0.4);
}

.highlight {
  color: #60a5fa;
  position: relative;
  display: inline-block;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  cursor: pointer;
  border: 1px solid transparent;
  transition: var(--transition-smooth);
  text-align: center;
}

.btn-primary {
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  color: #ffffff;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #3b82f6, #2563eb);
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(37, 99, 235, 0.6);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: #f8fafc;
  border: 1px solid rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(8px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.3);
  transform: translateY(-2px);
}

.btn:hover .btn-arrow {
  transform: translateX(4px);
}

/* YouTube Highlight Buttons */
.btn-youtube-glow {
  background: linear-gradient(135deg, #ff0000 0%, #dc2626 50%, #b91c1c 100%);
  color: #ffffff;
  padding: 14px 28px;
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  gap: 16px;
  box-shadow: 0 0 25px rgba(239, 68, 68, 0.6), 0 8px 30px rgba(0, 0, 0, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.3);
  position: relative;
  overflow: hidden;
  animation: pulseGlow 2.5s infinite;
  text-decoration: none;
}

@keyframes pulseGlow {
  0%, 100% { box-shadow: 0 0 25px rgba(239, 68, 68, 0.6), 0 8px 30px rgba(0, 0, 0, 0.6); }
  50% { box-shadow: 0 0 40px rgba(255, 0, 0, 0.9), 0 8px 35px rgba(239, 68, 68, 0.5); }
}

.btn-youtube-glow:hover {
  transform: translateY(-3px) scale(1.02);
  background: linear-gradient(135deg, #ff1a1a 0%, #ef4444 50%, #dc2626 100%);
  box-shadow: 0 0 45px rgba(255, 0, 0, 0.95), 0 12px 35px rgba(0, 0, 0, 0.8);
  color: #ffffff;
}

.yt-play-icon-box {
  width: 38px;
  height: 38px;
  background: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ff0000;
  flex-shrink: 0;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.4);
}

.yt-icon-svg {
  width: 20px;
  height: 20px;
  margin-left: 2px;
}

.btn-text-wrap {
  display: flex;
  flex-direction: column;
  text-align: left;
}

.btn-main-text {
  font-size: 1.12rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.5px;
}

.btn-highlight-sub {
  font-size: 0.78rem;
  font-weight: 600;
  color: #fef08a;
  letter-spacing: 0.2px;
}

.hero-consult-sub {
  padding: 16px 26px;
  font-size: 0.98rem;
}

/* Top Announcement Bar */
.top-bar {
  background: rgba(15, 23, 42, 0.9);
  border-bottom: 1px solid var(--border-subtle);
  padding: 8px 0;
  font-size: 0.85rem;
  color: var(--text-light);
}

.top-bar-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.announcement {
  display: flex;
  align-items: center;
  gap: 10px;
}

.badge-pill {
  background: #dc2626;
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: var(--radius-full);
}

.top-links {
  display: flex;
  align-items: center;
  gap: 16px;
}

.top-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
}

.top-link:hover {
  color: #ffffff;
}

.top-link.youtube:hover {
  color: #ff4d4d;
}

.icon-svg {
  width: 14px;
  height: 14px;
}

/* Header */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(7, 10, 18, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-subtle);
  transition: var(--transition-smooth);
}

.header.scrolled {
  background: rgba(7, 10, 18, 0.95);
  border-bottom-color: rgba(59, 130, 246, 0.2);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 74px;
}

.logo-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-logo {
  height: 46px;
  width: auto;
  border-radius: 6px;
  background: #ffffff;
  padding: 2px;
  object-fit: contain;
}

.brand-text {
  display: flex;
  flex-direction: column;
}

.logo-title {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: #ffffff;
}

.logo-sub {
  font-family: var(--font-num);
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--primary-blue);
  letter-spacing: 1.5px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-light);
  position: relative;
  padding: 6px 0;
}

.nav-link:hover {
  color: #60a5fa;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: #3b82f6;
  transition: width 0.2s ease;
}

.nav-link:hover::after {
  width: 100%;
}

.nav-cta-btn {
  background: rgba(59, 130, 246, 0.15);
  border: 1px solid rgba(59, 130, 246, 0.4);
  color: #93c5fd;
  padding: 9px 20px;
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 600;
  transition: var(--transition-smooth);
}

.nav-cta-btn:hover {
  background: #2563eb;
  color: #fff;
  border-color: #2563eb;
  box-shadow: 0 0 15px rgba(37, 99, 235, 0.5);
}

.desktop-only {
  display: inline-block;
}

.mobile-only {
  display: none;
}

/* Mobile Toggle */
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  flex-direction: column;
  gap: 5px;
}

.mobile-menu-btn span {
  display: block;
  width: 24px;
  height: 2px;
  background: #ffffff;
  transition: var(--transition-smooth);
}

/* Hero Section */
.hero-section {
  padding: 80px 0 100px;
  position: relative;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 48px;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.3);
  padding: 6px 16px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  color: #93c5fd;
  margin-bottom: 24px;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  background: #3b82f6;
  border-radius: 50%;
  box-shadow: 0 0 10px #3b82f6;
  animation: pulseAnimation 2s infinite;
}

@keyframes pulseAnimation {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(59, 130, 246, 0.7); }
  70% { transform: scale(1); box-shadow: 0 0 0 8px rgba(59, 130, 246, 0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(59, 130, 246, 0); }
}

.hero-title {
  font-size: 3.1rem;
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -1px;
  margin-bottom: 24px;
}

.hero-desc {
  font-size: 1.15rem;
  color: var(--text-light);
  line-height: 1.75;
  margin-bottom: 36px;
  word-break: keep-all;
}

.hero-desc strong {
  color: #ffffff;
  font-weight: 600;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 48px;
}

.yt-icon {
  width: 20px;
  height: 20px;
  color: #ff0000;
}

.hero-metrics {
  display: flex;
  align-items: center;
  gap: 28px;
  padding-top: 24px;
  border-top: 1px solid var(--border-subtle);
}

.metric-item {
  display: flex;
  flex-direction: column;
}

.metric-number {
  font-family: var(--font-num);
  font-size: 2.2rem;
  font-weight: 800;
  color: #ffffff;
  line-height: 1.1;
}

.metric-number .unit {
  color: var(--primary-blue);
  font-size: 1.5rem;
  margin-left: 2px;
}

.metric-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.metric-divider {
  width: 1px;
  height: 40px;
  background: var(--border-subtle);
}

/* Hero Visual & Instructor */
.hero-visual {
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
}

.hero-instructor-wrap {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: flex-end;
  margin-bottom: -36px;
  z-index: 2;
  width: 100%;
  max-width: 320px;
}

.hero-instructor-img {
  max-height: 380px;
  width: auto;
  max-width: 100%;
  object-fit: contain;
  filter: drop-shadow(0 15px 35px rgba(0, 0, 0, 0.7)) drop-shadow(0 0 35px rgba(59, 130, 246, 0.4));
  transition: var(--transition-smooth);
  animation: floatSubtle 4s ease-in-out infinite;
}

@keyframes floatSubtle {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

.instructor-image-glow-bg {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  width: 250px;
  height: 250px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.45) 0%, rgba(6, 182, 212, 0.2) 50%, transparent 70%);
  filter: blur(20px);
  z-index: -1;
  pointer-events: none;
}

.hero-floating-badge {
  position: absolute;
  bottom: 25px;
  right: -15px;
  background: rgba(15, 23, 42, 0.92);
  border: 1px solid rgba(59, 130, 246, 0.5);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  padding: 10px 18px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.6), 0 0 20px rgba(59, 130, 246, 0.3);
  z-index: 3;
}

.hero-floating-badge .badge-icon {
  font-size: 1.4rem;
}

.badge-text-group strong {
  display: block;
  font-size: 0.92rem;
  color: #fbbf24;
  line-height: 1.2;
}

.badge-text-group span {
  font-size: 0.78rem;
  color: #cbd5e1;
}

/* Glass Hero Card */
.glass-hero-card {
  width: 100%;
  margin-top: 0;
  z-index: 1;
  background: var(--bg-card);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-lg);
  padding: 36px;
  box-shadow: var(--shadow-card), var(--shadow-glow);
  position: relative;
  overflow: hidden;
}

.glass-hero-card::before {
  content: '';
  position: absolute;
  top: -50px;
  right: -50px;
  width: 150px;
  height: 150px;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.25), transparent 70%);
  pointer-events: none;
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.badge-tag {
  font-family: var(--font-num);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  color: #38bdf8;
  background: rgba(56, 189, 248, 0.1);
  padding: 4px 10px;
  border-radius: var(--radius-full);
}

.card-status {
  font-size: 0.8rem;
  font-weight: 600;
  color: #10b981;
}

.quote-box {
  background: rgba(255, 255, 255, 0.03);
  border-left: 3px solid var(--accent-gold);
  padding: 18px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-bottom: 28px;
  position: relative;
}

.quote-mark {
  font-size: 3rem;
  line-height: 0.5;
  color: var(--accent-gold);
  opacity: 0.3;
  margin-bottom: 8px;
}

.quote-text {
  font-size: 1.05rem;
  color: #f1f5f9;
  line-height: 1.6;
}

.quote-text strong {
  color: #fbbf24;
}

.quote-author {
  margin-top: 12px;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.quote-author strong {
  color: #ffffff;
}

.quote-author span {
  color: var(--text-muted);
}

.signature-features {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: 28px;
}

.feat-item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-subtle);
  padding: 12px 16px;
  border-radius: var(--radius-md);
  transition: var(--transition-smooth);
}

.feat-item:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(59, 130, 246, 0.4);
  transform: translateX(4px);
}

.feat-icon {
  font-size: 1.4rem;
  line-height: 1;
}

.feat-text strong {
  display: block;
  font-size: 0.95rem;
  color: #ffffff;
}

.feat-text span {
  font-size: 0.82rem;
  color: var(--text-muted);
}

.blog-preview-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 12px 18px;
  background: rgba(3, 199, 90, 0.1);
  border: 1px solid rgba(3, 199, 90, 0.3);
  border-radius: var(--radius-md);
  color: #34d399;
  font-size: 0.9rem;
  font-weight: 600;
  transition: var(--transition-smooth);
}

.blog-preview-btn:hover {
  background: rgba(3, 199, 90, 0.2);
  border-color: rgba(3, 199, 90, 0.5);
  transform: translateY(-2px);
}

/* Sections Global */
.section {
  padding: 100px 0;
  position: relative;
}

.section-head {
  margin-bottom: 60px;
}

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

.section-sub {
  display: inline-block;
  font-family: var(--font-num);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--primary-blue);
  margin-bottom: 12px;
  text-transform: uppercase;
}

.section-title {
  font-size: 2.4rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  margin-bottom: 16px;
  color: #ffffff;
}

.section-desc {
  font-size: 1.1rem;
  color: var(--text-light);
  max-width: 720px;
  margin: 0 auto;
  word-break: keep-all;
}

/* About Section */
.about-grid {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: 48px;
  align-items: center;
}

.about-photo-card {
  position: relative;
}

.photo-container {
  position: relative;
  background: linear-gradient(145deg, #111a2e, #090e1a);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-lg);
  padding: 36px 28px 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  box-shadow: var(--shadow-card);
  overflow: hidden;
}

.instructor-photo-backdrop {
  position: absolute;
  top: 40px;
  left: 50%;
  transform: translateX(-50%);
  width: 260px;
  height: 260px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(239, 68, 68, 0.25) 0%, rgba(245, 158, 11, 0.1) 50%, transparent 70%);
  filter: blur(25px);
  z-index: 0;
  pointer-events: none;
}

.instructor-photo-main {
  position: relative;
  z-index: 1;
  max-height: 420px;
  width: auto;
  max-width: 100%;
  object-fit: contain;
  filter: drop-shadow(0 15px 30px rgba(0, 0, 0, 0.7)) drop-shadow(0 0 25px rgba(239, 68, 68, 0.25));
  margin-bottom: 16px;
  transition: var(--transition-smooth);
}

.instructor-photo-main:hover {
  transform: scale(1.02);
}

.photo-overlay-card {
  position: relative;
  z-index: 2;
  text-align: center;
  width: 100%;
}

.badge-role {
  display: inline-block;
  background: rgba(239, 68, 68, 0.15);
  color: #f87171;
  border: 1px solid rgba(239, 68, 68, 0.3);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 4px 14px;
  border-radius: var(--radius-full);
  margin-bottom: 8px;
}

.photo-overlay-card h3 {
  font-size: 1.6rem;
  margin-bottom: 6px;
}

.photo-overlay-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.philosophy-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin-bottom: 24px;
}

.philosophy-title {
  font-size: 1.3rem;
  margin-bottom: 24px;
  color: #f8fafc;
}

.principle-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.principle-item {
  display: flex;
  gap: 18px;
  align-items: flex-start;
}

.p-num {
  font-family: var(--font-num);
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--primary-blue);
  background: rgba(59, 130, 246, 0.1);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  line-height: 1;
}

.p-content h4 {
  font-size: 1.05rem;
  margin-bottom: 6px;
  color: #ffffff;
}

.p-content p {
  font-size: 0.92rem;
  color: var(--text-light);
  line-height: 1.6;
  word-break: keep-all;
}

.exam-quote-banner {
  display: flex;
  align-items: center;
  gap: 18px;
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.1), rgba(245, 158, 11, 0.03));
  border: 1px solid rgba(245, 158, 11, 0.3);
  padding: 22px 26px;
  border-radius: var(--radius-md);
}

.eq-icon {
  font-size: 2.2rem;
  line-height: 1;
}

.eq-body strong {
  display: block;
  font-size: 1.1rem;
  color: #fbbf24;
  margin-bottom: 4px;
}

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

/* Original Textbooks Section */
.textbooks-section {
  background: radial-gradient(circle at 20% 50%, rgba(37, 99, 235, 0.08), transparent 50%), var(--bg-dark);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.textbooks-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
  gap: 28px;
}

.textbook-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  transition: var(--transition-smooth);
  position: relative;
}

.textbook-card:hover {
  transform: translateY(-8px);
  border-color: var(--border-glow);
  box-shadow: var(--shadow-card), 0 0 30px rgba(59, 130, 246, 0.25);
  background: var(--bg-card-hover);
}

.textbook-card.featured-book {
  border-color: rgba(59, 130, 246, 0.4);
  background: linear-gradient(180deg, rgba(26, 41, 74, 0.8), rgba(15, 23, 42, 0.9));
}

.book-badge-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.book-badge {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  background: rgba(59, 130, 246, 0.2);
  color: #60a5fa;
  border: 1px solid rgba(59, 130, 246, 0.4);
}

.book-badge.gold {
  background: rgba(245, 158, 11, 0.2);
  color: #fbbf24;
  border-color: rgba(245, 158, 11, 0.4);
}

.book-badge.cyan {
  background: rgba(6, 182, 212, 0.2);
  color: #22d3ee;
  border-color: rgba(6, 182, 212, 0.4);
}

.book-badge.red {
  background: rgba(239, 68, 68, 0.2);
  color: #f87171;
  border-color: rgba(239, 68, 68, 0.4);
}

.book-target {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 600;
}

/* 3D Book Cover Mockup */
.book-cover-mockup {
  position: relative;
  height: 220px;
  margin: 0 auto 24px;
  display: flex;
  justify-content: center;
  perspective: 800px;
}

.book-front {
  width: 170px;
  height: 220px;
  border-radius: 4px 10px 10px 4px;
  padding: 20px 16px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: 8px 12px 25px rgba(0, 0, 0, 0.7), inset 4px 0 8px rgba(255, 255, 255, 0.1);
  transform: rotateY(-10deg);
  transition: transform 0.4s ease;
  border-left: 5px solid rgba(0, 0, 0, 0.4);
}

.textbook-card:hover .book-front {
  transform: rotateY(0deg) scale(1.04);
}

.book-front.blue-theme {
  background: linear-gradient(135deg, #1e3a8a, #0f172a);
  border-top: 2px solid #60a5fa;
}

.book-front.gold-theme {
  background: linear-gradient(135deg, #78350f, #1e1e1e);
  border-top: 2px solid #fbbf24;
}

.book-front.cyan-theme {
  background: linear-gradient(135deg, #164e63, #0f172a);
  border-top: 2px solid #22d3ee;
}

.book-front.red-theme {
  background: linear-gradient(135deg, #881337, #1e1e1e);
  border-top: 2px solid #f87171;
}

.book-series {
  font-size: 0.6rem;
  font-weight: 800;
  letter-spacing: 1.5px;
  color: rgba(255, 255, 255, 0.7);
  text-transform: uppercase;
}

.book-title {
  font-size: 1.05rem;
  font-weight: 800;
  line-height: 1.25;
  color: #ffffff;
  margin-top: 6px;
}

.book-sub {
  font-size: 0.82rem;
  color: #93c5fd;
  font-weight: 700;
}

.book-slogan {
  font-size: 0.65rem;
  color: rgba(255, 255, 255, 0.7);
  line-height: 1.35;
  margin: 6px 0;
}

.book-author {
  font-size: 0.68rem;
  color: rgba(255, 255, 255, 0.5);
  align-self: flex-end;
}

.book-info {
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.book-name {
  font-size: 1.15rem;
  margin-bottom: 8px;
  color: #ffffff;
}

.book-intro {
  font-size: 0.88rem;
  color: var(--text-light);
  line-height: 1.6;
  margin-bottom: 16px;
  word-break: keep-all;
}

.book-features {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 20px;
  border-top: 1px solid var(--border-subtle);
  padding-top: 14px;
  flex-grow: 1;
}

.book-features li {
  font-size: 0.84rem;
  color: var(--text-muted);
  display: flex;
  align-items: flex-start;
  gap: 8px;
  line-height: 1.45;
}

.book-features li span {
  color: #10b981;
  font-weight: bold;
  flex-shrink: 0;
}

.book-footer {
  border-top: 1px solid var(--border-subtle);
  padding-top: 16px;
}

.book-link-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.88rem;
  font-weight: 600;
  color: #38bdf8;
  transition: var(--transition-smooth);
}

.book-link-btn:hover {
  color: #93c5fd;
  transform: translateX(4px);
}

/* Target Schools Section */
.schools-section {
  background: rgba(15, 23, 42, 0.4);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.school-tab-buttons {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 36px;
}

.school-btn {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-light);
  border: 1px solid var(--border-subtle);
  padding: 12px 24px;
  border-radius: var(--radius-full);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.school-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #ffffff;
}

.school-btn.active {
  background: #2563eb;
  color: #ffffff;
  border-color: #2563eb;
  box-shadow: 0 4px 18px rgba(37, 99, 235, 0.4);
}

.school-detail-card {
  background: var(--bg-card);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-card);
  transition: var(--transition-smooth);
}

/* System 4-Step Grid */
.system-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.system-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition-smooth);
}

.system-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-glow);
  box-shadow: var(--shadow-card), var(--shadow-glow);
  background: var(--bg-card-hover);
}

.system-card.highlight-card {
  background: linear-gradient(180deg, rgba(30, 41, 59, 0.9), rgba(15, 23, 42, 0.95));
  border-color: rgba(245, 158, 11, 0.4);
}

.system-card.highlight-card:hover {
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.8), 0 0 25px rgba(245, 158, 11, 0.3);
}

.step-badge {
  font-family: var(--font-num);
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--primary-blue);
  background: rgba(59, 130, 246, 0.15);
  padding: 3px 10px;
  border-radius: var(--radius-full);
  align-self: flex-start;
  margin-bottom: 20px;
}

.step-badge.lock-badge {
  color: #fbbf24;
  background: rgba(245, 158, 11, 0.15);
}

.card-icon {
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.card-title {
  font-size: 1.35rem;
  margin-bottom: 4px;
}

.card-sub {
  font-size: 0.9rem;
  font-weight: 600;
  color: #38bdf8;
  margin-bottom: 16px;
}

.highlight-card .card-sub {
  color: #fbbf24;
}

.card-text {
  font-size: 0.92rem;
  color: var(--text-light);
  line-height: 1.65;
  margin-bottom: 20px;
  flex-grow: 1;
  word-break: keep-all;
}

.check-list {
  border-top: 1px solid var(--border-subtle);
  padding-top: 16px;
}

.check-list li {
  font-size: 0.85rem;
  color: var(--text-muted);
  position: relative;
  padding-left: 18px;
  margin-bottom: 8px;
}

.check-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: #10b981;
  font-weight: 700;
}

/* Curriculum Section */
.curriculum-tab-container {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 36px;
  box-shadow: var(--shadow-card);
}

.curri-tabs {
  display: flex;
  gap: 12px;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 20px;
  margin-bottom: 30px;
  overflow-x: auto;
}

.curri-tab-btn {
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-muted);
  border: 1px solid var(--border-subtle);
  padding: 12px 24px;
  border-radius: var(--radius-md);
  font-size: 0.98rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: var(--transition-smooth);
}

.curri-tab-btn:hover {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.08);
}

.curri-tab-btn.active {
  background: #2563eb;
  color: #ffffff;
  border-color: #2563eb;
  box-shadow: 0 4px 15px rgba(37, 99, 235, 0.4);
}

/* Media Section */
.media-section {
  background: rgba(15, 23, 42, 0.5);
  border-top: 1px solid var(--border-subtle);
}

.media-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 36px;
}

.media-column {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px;
  display: flex;
  flex-direction: column;
}

.media-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-subtle);
}

.header-left {
  display: flex;
  align-items: center;
  gap: 14px;
}

.media-icon.yt {
  width: 38px;
  height: 38px;
  color: #ef4444;
}

.naver-icon {
  width: 38px;
  height: 38px;
  background: #03c75a;
  color: #ffffff;
  font-weight: 900;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  font-size: 1.2rem;
}

.header-left h3 {
  font-size: 1.25rem;
}

.header-left span {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.channel-btn {
  font-size: 0.85rem;
  font-weight: 600;
  padding: 8px 16px;
  border-radius: var(--radius-full);
}

.yt-btn {
  background: rgba(239, 68, 68, 0.15);
  color: #f87171;
  border: 1px solid rgba(239, 68, 68, 0.4);
}

.yt-btn:hover {
  background: #ef4444;
  color: #ffffff;
}

.blog-btn {
  background: rgba(3, 199, 90, 0.15);
  color: #34d399;
  border: 1px solid rgba(3, 199, 90, 0.4);
}

.blog-btn:hover {
  background: #03c75a;
  color: #ffffff;
}

.video-list, .blog-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.video-card, .blog-post-card {
  display: flex;
  gap: 16px;
  padding: 16px;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  transition: var(--transition-smooth);
}

.video-card:hover, .blog-post-card:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(59, 130, 246, 0.35);
  transform: translateY(-2px);
}

.video-thumbnail-placeholder {
  width: 110px;
  height: 75px;
  background: #1e293b;
  border-radius: 6px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
}

.play-btn-circle {
  font-size: 1.2rem;
  color: #ef4444;
}

.video-tag {
  font-size: 0.65rem;
  background: rgba(0, 0, 0, 0.6);
  padding: 2px 6px;
  border-radius: 4px;
  margin-top: 4px;
  color: #ffffff;
}

.video-info h4 {
  font-size: 0.95rem;
  margin-bottom: 6px;
  line-height: 1.4;
}

.video-info p {
  font-size: 0.82rem;
  color: var(--text-muted);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.blog-post-card {
  flex-direction: column;
  gap: 6px;
}

.post-category {
  font-size: 0.75rem;
  font-weight: 700;
  color: #34d399;
}

.post-title {
  font-size: 0.98rem;
  line-height: 1.4;
  color: #ffffff;
}

.post-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.post-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.78rem;
  color: #64748b;
  margin-top: 6px;
}

/* FAQ Section */
.faq-accordion {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition-smooth);
}

.faq-item:hover {
  border-color: rgba(59, 130, 246, 0.3);
}

.faq-question {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
  background: none;
  border: none;
  color: #ffffff;
  font-size: 1.05rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
}

.faq-icon {
  font-size: 1.4rem;
  color: var(--primary-blue);
  transition: transform 0.3s ease;
  line-height: 1;
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  padding: 0 24px;
}

.faq-item.active .faq-answer {
  max-height: 250px;
  padding: 0 24px 22px 24px;
}

.faq-answer p {
  font-size: 0.95rem;
  color: var(--text-light);
  line-height: 1.7;
}

/* Consultation Section */
.consultation-section {
  background: radial-gradient(circle at 80% 20%, rgba(37, 99, 235, 0.12), transparent 50%), var(--bg-dark);
  border-top: 1px solid var(--border-subtle);
}

.consultation-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: center;
}

.consultation-title {
  font-size: 2.4rem;
  line-height: 1.3;
  margin-bottom: 18px;
}

.consultation-desc {
  font-size: 1.05rem;
  color: var(--text-light);
  margin-bottom: 32px;
}

.c-perks {
  display: flex;
  flex-direction: column;
  gap: 18px;
  margin-bottom: 36px;
}

.c-perk-item {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}

.c-check {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background: rgba(16, 185, 129, 0.2);
  color: #10b981;
  border-radius: 50%;
  font-size: 0.85rem;
  font-weight: 800;
  flex-shrink: 0;
  margin-top: 2px;
}

.c-perk-item strong {
  display: block;
  font-size: 1rem;
  color: #ffffff;
}

.c-perk-item p {
  font-size: 0.88rem;
  color: var(--text-muted);
}

.direct-contact-card {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.dc-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: block;
}

.dc-val {
  font-size: 1rem;
  font-weight: 700;
  color: #ffffff;
}

.dc-val.highlight-val {
  color: #34d399;
}

/* Consultation Form */
.consultation-form-wrapper {
  background: var(--bg-card);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-card), var(--shadow-glow);
}

.form-title {
  font-size: 1.5rem;
  margin-bottom: 6px;
}

.form-subtitle {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.form-group {
  margin-bottom: 18px;
}

.form-group label {
  display: block;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-light);
  margin-bottom: 6px;
}

.required {
  color: #ef4444;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.consultation-form input,
.consultation-form select,
.consultation-form textarea {
  width: 100%;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  color: #ffffff;
  font-size: 0.95rem;
  font-family: inherit;
  transition: var(--transition-smooth);
}

.consultation-form select option {
  background: #0f172a;
  color: #ffffff;
}

.consultation-form input:focus,
.consultation-form select:focus,
.consultation-form textarea:focus {
  outline: none;
  border-color: #3b82f6;
  background: rgba(255, 255, 255, 0.08);
  box-shadow: 0 0 10px rgba(59, 130, 246, 0.3);
}

.form-privacy {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 24px;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.form-privacy input[type="checkbox"] {
  width: auto;
  accent-color: #2563eb;
}

.submit-btn {
  width: 100%;
  padding: 16px;
  font-size: 1.05rem;
}

/* Location Section */
.location-card {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 32px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-card);
}

.map-placeholder {
  height: 100%;
  min-height: 280px;
  background: radial-gradient(circle, #1e293b, #0f172a);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 24px;
  text-align: center;
  position: relative;
}

.pin-marker {
  position: relative;
  margin-bottom: 12px;
}

.pin-point {
  font-size: 2.4rem;
}

.pin-pulse {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: rgba(59, 130, 246, 0.3);
  animation: pulseAnimation 2s infinite;
}

.map-label strong {
  display: block;
  font-size: 1.15rem;
  color: #ffffff;
}

.map-label span {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.map-open-btn {
  margin-top: 16px;
  font-size: 0.85rem;
  padding: 8px 18px;
}

.loc-info-details {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 20px;
}

.loc-item {
  display: flex;
  gap: 16px;
  align-items: flex-start;
}

.loc-icon {
  font-size: 1.5rem;
}

.loc-item strong {
  display: block;
  font-size: 1rem;
  color: #ffffff;
  margin-bottom: 4px;
}

.loc-item p {
  font-size: 0.9rem;
  color: var(--text-light);
  line-height: 1.6;
}

.loc-item a {
  color: #60a5fa;
}

.w-full {
  width: 100%;
}

/* Footer */
.footer {
  background: #04070e;
  border-top: 1px solid var(--border-subtle);
  padding: 60px 0 24px;
}

.footer-content {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-logo-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.footer-logo {
  height: 38px;
  background: #ffffff;
  border-radius: 4px;
  padding: 2px;
}

.footer-title {
  font-size: 1.25rem;
  font-weight: 800;
  color: #ffffff;
}

.footer-slogan {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 20px;
}

.footer-socials {
  display: flex;
  gap: 10px;
}

.social-btn {
  width: 36px;
  height: 36px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  font-weight: 700;
  color: #ffffff;
  transition: var(--transition-smooth);
}

.social-btn:hover {
  background: #03c75a;
  border-color: #03c75a;
}

.social-btn.yt:hover {
  background: #ef4444;
  border-color: #ef4444;
}

.social-btn.ig:hover {
  background: #e1306c;
  border-color: #e1306c;
}

.footer-links-group {
  display: flex;
  justify-content: space-around;
  gap: 24px;
}

.footer-col h4 {
  font-size: 0.95rem;
  margin-bottom: 16px;
  color: #ffffff;
}

.footer-col a {
  display: block;
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 10px;
}

.footer-col a:hover {
  color: #60a5fa;
}

.domain-badge {
  font-family: var(--font-num);
  display: inline-block;
  background: rgba(59, 130, 246, 0.15);
  border: 1px solid rgba(59, 130, 246, 0.3);
  color: #93c5fd;
  font-size: 0.82rem;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  margin-bottom: 8px;
}

.blog-ref {
  font-size: 0.82rem;
  color: var(--text-muted);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 24px;
  font-size: 0.82rem;
  color: #64748b;
}

.fb-container {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

/* Floating Actions Bar */
.floating-bar {
  position: fixed;
  right: 24px;
  bottom: 30px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 99;
}

.floating-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border-radius: var(--radius-full);
  font-size: 0.88rem;
  font-weight: 700;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(8px);
  transition: var(--transition-smooth);
}

.floating-btn:hover {
  transform: translateY(-3px) scale(1.03);
}

.floating-btn.consult {
  background: #2563eb;
  color: #ffffff;
  border: 1px solid #3b82f6;
}

.floating-btn.blog {
  background: #03c75a;
  color: #ffffff;
}

.floating-btn.youtube {
  background: #ef4444;
  color: #ffffff;
}

.floating-btn.top-scroll {
  width: 42px;
  height: 42px;
  padding: 0;
  justify-content: center;
  background: rgba(15, 23, 42, 0.85);
  color: #ffffff;
  border: 1px solid var(--border-subtle);
  cursor: pointer;
  align-self: flex-end;
}

/* Modal */
.modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(8px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 20px;
}

.modal-backdrop.active {
  display: flex;
}

.modal-card {
  background: #0f172a;
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-lg);
  padding: 40px;
  max-width: 480px;
  width: 100%;
  text-align: center;
  box-shadow: var(--shadow-card), var(--shadow-glow);
  animation: modalScaleUp 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes modalScaleUp {
  from { transform: scale(0.9); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

.modal-icon {
  font-size: 3rem;
  margin-bottom: 16px;
}

.modal-title {
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.modal-desc {
  font-size: 0.95rem;
  color: var(--text-light);
  line-height: 1.6;
  margin-bottom: 28px;
}

.modal-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
}

/* Responsive Media Queries */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }
  .system-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .about-grid {
    grid-template-columns: 1fr;
  }
  .media-grid {
    grid-template-columns: 1fr;
  }
  .consultation-grid {
    grid-template-columns: 1fr;
  }
  .location-card {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .desktop-only {
    display: none;
  }
  .mobile-only {
    display: block;
  }
  .mobile-menu-btn {
    display: flex;
  }
  .nav-menu {
    position: fixed;
    top: 74px;
    left: 0;
    width: 100%;
    background: rgba(7, 10, 18, 0.98);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-subtle);
    flex-direction: column;
    padding: 24px;
    gap: 18px;
    transform: translateY(-120%);
    transition: transform 0.3s ease;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.8);
  }
  .nav-menu.open {
    transform: translateY(0);
  }
  .hero-title {
    font-size: 2.2rem;
  }
  .system-grid {
    grid-template-columns: 1fr;
  }
  .form-row {
    grid-template-columns: 1fr;
  }
  .footer-content {
    grid-template-columns: 1fr;
  }
  .floating-bar .f-text {
    display: none;
  }
  .floating-btn {
    width: 44px;
    height: 44px;
    padding: 0;
    justify-content: center;
  }
}

/* Mid-Page YouTube Highlight Banner */
.mid-yt-banner-section {
  padding: 70px 0;
  position: relative;
  z-index: 10;
}

.yt-mega-highlight-card {
  position: relative;
  background: linear-gradient(135deg, #1c080d 0%, #1e1124 45%, #0b172a 100%);
  border: 2px solid rgba(239, 68, 68, 0.55);
  border-radius: var(--radius-lg);
  padding: 48px 56px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 40px;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.85), 0 0 45px rgba(239, 68, 68, 0.35);
  overflow: hidden;
}

.yt-mega-backdrop {
  position: absolute;
  top: -50%;
  right: -20%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(239, 68, 68, 0.3) 0%, transparent 70%);
  filter: blur(40px);
  pointer-events: none;
}

.yt-mega-content {
  max-width: 620px;
  position: relative;
  z-index: 1;
}

.yt-live-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(239, 68, 68, 0.2);
  color: #fca5a5;
  border: 1px solid rgba(239, 68, 68, 0.45);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  padding: 4px 14px;
  border-radius: var(--radius-full);
  margin-bottom: 16px;
}

.live-pulse-dot {
  width: 8px;
  height: 8px;
  background: #ef4444;
  border-radius: 50%;
  box-shadow: 0 0 10px #ef4444;
  animation: pulseDotRed 1.5s infinite;
}

@keyframes pulseDotRed {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.8); }
}

.yt-mega-title {
  font-size: 2rem;
  font-weight: 800;
  line-height: 1.35;
  color: #ffffff;
  margin-bottom: 14px;
  letter-spacing: -0.5px;
}

.yt-highlight-red {
  color: #ff4d4d;
  text-shadow: 0 0 25px rgba(255, 77, 77, 0.6);
}

.yt-mega-desc {
  font-size: 1.05rem;
  color: #cbd5e1;
  line-height: 1.7;
}

.yt-mega-action {
  position: relative;
  z-index: 1;
  flex-shrink: 0;
}

.btn-youtube-mega-glow {
  background: linear-gradient(135deg, #ff0000 0%, #e11d48 50%, #be123c 100%);
  color: #ffffff;
  padding: 20px 38px;
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  gap: 20px;
  border: 2px solid rgba(255, 255, 255, 0.4);
  box-shadow: 0 0 35px rgba(239, 68, 68, 0.7), 0 12px 30px rgba(0, 0, 0, 0.8);
  transition: var(--transition-smooth);
  animation: pulseGlow 2.5s infinite;
  text-decoration: none;
}

.btn-youtube-mega-glow:hover {
  transform: translateY(-4px) scale(1.03);
  background: linear-gradient(135deg, #ff1a1a 0%, #f43f5e 50%, #e11d48 100%);
  box-shadow: 0 0 55px rgba(255, 0, 0, 1), 0 16px 40px rgba(0, 0, 0, 0.9);
  color: #ffffff;
}

.mega-play-circle {
  width: 48px;
  height: 48px;
  background: #ffffff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ff0000;
  flex-shrink: 0;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.4);
}

.mega-svg {
  width: 24px;
  height: 24px;
  margin-left: 3px;
}

.mega-text-group {
  display: flex;
  flex-direction: column;
  text-align: left;
}

.mega-main-title {
  font-size: 1.35rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.5px;
}

.mega-sub-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: #fef08a;
  margin-top: 4px;
}

@media (max-width: 960px) {
  .yt-mega-highlight-card {
    flex-direction: column;
    text-align: center;
    padding: 36px 24px;
    gap: 28px;
  }
  .yt-mega-content {
    max-width: 100%;
  }
  .yt-mega-title {
    font-size: 1.6rem;
  }
  .btn-youtube-mega-glow {
    width: 100%;
    justify-content: center;
    padding: 16px 24px;
  }
}