/* ==========================================
   유인숙 강사 프로필 웹사이트 - 메인 스타일시트
   ========================================== */

/* === CSS 변수 정의 === */
:root {
    --primary: #1a56c4;
    --primary-dark: #1240a0;
    --primary-light: #3b7de8;
    --secondary: #0ea5e9;
    --accent: #6366f1;
    --accent-warm: #f59e0b;
    --text-dark: #0f172a;
    --text-mid: #334155;
    --text-light: #64748b;
    --text-muted: #94a3b8;
    --bg-white: #ffffff;
    --bg-light: #f8fafc;
    --bg-section: #f1f5f9;
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.08), 0 2px 8px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 40px rgba(0,0,0,0.1), 0 4px 16px rgba(0,0,0,0.06);
    --shadow-xl: 0 20px 60px rgba(0,0,0,0.12);
    --gradient-main: linear-gradient(135deg, #0f2167 0%, #1a56c4 40%, #0ea5e9 100%);
    --gradient-card: linear-gradient(135deg, #1a56c4, #6366f1);
    --gradient-warm: linear-gradient(135deg, #f59e0b, #ef4444);
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-xl: 32px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
    font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--text-dark);
    background-color: var(--bg-white);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

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

ul { list-style: none; }

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

/* === Scrollbar === */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-light); }
::-webkit-scrollbar-thumb { background: var(--primary-light); border-radius: 3px; }

/* ==========================================
   NAVIGATION
   ========================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: var(--transition);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 10px 0;
    box-shadow: 0 2px 20px rgba(0,0,0,0.08);
}

.navbar.scrolled .nav-logo .logo-text { color: var(--primary); }
.navbar.scrolled .nav-logo .logo-sub { color: var(--text-light); }
.navbar.scrolled .nav-link { color: var(--text-mid); }
.navbar.scrolled .nav-link:hover { color: var(--primary); }
.navbar.scrolled .hamburger span { background: var(--text-mid); }

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

.logo-text {
    font-family: 'Noto Serif KR', serif;
    font-size: 1.3rem;
    font-weight: 700;
    color: #fff;
    letter-spacing: -0.02em;
}

.logo-sub {
    font-size: 0.7rem;
    color: rgba(255,255,255,0.75);
    letter-spacing: 0.02em;
}

.nav-links {
    display: flex;
    gap: 8px;
    align-items: center;
}

.nav-link {
    font-size: 0.875rem;
    font-weight: 500;
    color: rgba(255,255,255,0.9);
    padding: 8px 14px;
    border-radius: 8px;
    position: relative;
    transition: var(--transition);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 4px;
    left: 14px;
    right: 14px;
    height: 2px;
    background: var(--accent-warm);
    transform: scaleX(0);
    transition: var(--transition);
    border-radius: 1px;
}

.nav-link:hover::after { transform: scaleX(1); }

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background: #fff;
    border-radius: 2px;
    transition: var(--transition);
}

/* ==========================================
   HERO SECTION
   ========================================== */
.hero {
    min-height: 100vh;
    background: var(--gradient-main);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    text-align: center;
    padding: 100px 24px 60px;
}

/* Background Shapes */
.hero-bg-shapes { position: absolute; inset: 0; pointer-events: none; }

.shape {
    position: absolute;
    border-radius: 50%;
    opacity: 0.08;
}

.shape-1 {
    width: 600px; height: 600px;
    background: radial-gradient(circle, #fff, transparent);
    top: -200px; right: -200px;
    animation: floatShape 8s ease-in-out infinite;
}

.shape-2 {
    width: 400px; height: 400px;
    background: radial-gradient(circle, var(--secondary), transparent);
    bottom: -100px; left: -100px;
    opacity: 0.15;
    animation: floatShape 10s ease-in-out infinite reverse;
}

.shape-3 {
    width: 200px; height: 200px;
    background: radial-gradient(circle, var(--accent), transparent);
    top: 30%; left: 10%;
    opacity: 0.2;
    animation: floatShape 6s ease-in-out infinite;
}

.shape-4 {
    width: 150px; height: 150px;
    background: radial-gradient(circle, var(--accent-warm), transparent);
    bottom: 20%; right: 15%;
    opacity: 0.25;
    animation: floatShape 7s ease-in-out infinite reverse;
}

@keyframes floatShape {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(20px, -20px) scale(1.05); }
    66% { transform: translate(-10px, 15px) scale(0.95); }
}

/* Particles */
.hero-particles {
    position: absolute;
    inset: 0;
    pointer-events: none;
    overflow: hidden;
}

.particle {
    position: absolute;
    border-radius: 50%;
    background: rgba(255,255,255,0.4);
    animation: particleFloat linear infinite;
}

@keyframes particleFloat {
    0% { transform: translateY(100vh) rotate(0deg); opacity: 0; }
    10% { opacity: 1; }
    90% { opacity: 1; }
    100% { transform: translateY(-100px) rotate(360deg); opacity: 0; }
}

/* Hero Content */
.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
    width: 100%;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(255,255,255,0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.25);
    color: #fff;
    font-size: 0.8rem;
    font-weight: 600;
    padding: 8px 20px;
    border-radius: 50px;
    margin-bottom: 28px;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    animation: fadeInDown 0.8s ease both;
}

.hero-badge i { color: var(--accent-warm); font-size: 0.9rem; }

/* Avatar */
.hero-avatar {
    position: relative;
    width: 140px;
    height: 140px;
    margin: 0 auto 28px;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.avatar-ring {
    position: absolute;
    inset: -8px;
    border-radius: 50%;
    background: conic-gradient(
        var(--accent-warm) 0deg,
        var(--secondary) 90deg,
        var(--accent) 180deg,
        var(--primary-light) 270deg,
        var(--accent-warm) 360deg
    );
    animation: rotateSpin 4s linear infinite;
}

@keyframes rotateSpin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.avatar-inner {
    position: absolute;
    inset: 6px;
    background: linear-gradient(135deg, #1e3a8a, #1d4ed8);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 4px solid rgba(255,255,255,0.15);
}

.avatar-inner i {
    font-size: 3.5rem;
    color: rgba(255,255,255,0.9);
}

.avatar-badge-icon {
    position: absolute;
    bottom: 0;
    right: 0;
    width: 40px;
    height: 40px;
    background: var(--accent-warm);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 3px solid rgba(15, 33, 103, 0.9);
    box-shadow: 0 4px 12px rgba(245,158,11,0.4);
}

.avatar-badge-icon i { font-size: 0.9rem; color: #fff; }

.hero-name {
    font-family: 'Noto Serif KR', serif;
    font-size: clamp(2.5rem, 6vw, 4rem);
    font-weight: 700;
    color: #fff;
    letter-spacing: -0.03em;
    margin-bottom: 8px;
    animation: fadeInUp 0.8s ease 0.3s both;
}

.hero-title {
    font-size: clamp(1rem, 2.5vw, 1.3rem);
    color: rgba(255,255,255,0.85);
    font-weight: 400;
    margin-bottom: 28px;
    letter-spacing: 0.05em;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.hero-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    margin-bottom: 36px;
    animation: fadeInUp 0.8s ease 0.5s both;
}

.tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: rgba(255,255,255,0.12);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,255,255,0.2);
    color: rgba(255,255,255,0.95);
    font-size: 0.82rem;
    font-weight: 500;
    padding: 7px 16px;
    border-radius: 50px;
    transition: var(--transition);
}

.tag:hover {
    background: rgba(255,255,255,0.22);
    transform: translateY(-2px);
}

.tag i { color: var(--accent-warm); font-size: 0.75rem; }

/* Stats */
.hero-stats {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    background: rgba(255,255,255,0.1);
    backdrop-filter: blur(12px);
    border: 1px solid rgba(255,255,255,0.2);
    border-radius: var(--radius-lg);
    padding: 24px 32px;
    margin: 0 auto 32px;
    max-width: 480px;
    animation: fadeInUp 0.8s ease 0.6s both;
}

.stat-item {
    flex: 1;
    text-align: center;
}

.stat-number {
    font-family: 'Noto Serif KR', serif;
    font-size: 2.2rem;
    font-weight: 700;
    color: #fff;
    line-height: 1;
    margin-bottom: 4px;
}

.stat-number::after {
    content: '+';
    font-size: 1.2rem;
    color: var(--accent-warm);
}

.stat-label {
    font-size: 0.72rem;
    color: rgba(255,255,255,0.7);
    font-weight: 500;
    letter-spacing: 0.04em;
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: rgba(255,255,255,0.2);
    margin: 0 20px;
}

/* CTA Buttons */
.hero-cta {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease 0.7s both;
}

.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: #fff;
    color: var(--primary);
    font-size: 0.92rem;
    font-weight: 700;
    padding: 14px 28px;
    border-radius: 50px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.15);
    transition: var(--transition);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 32px rgba(0,0,0,0.2);
    background: #f0f7ff;
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(255,255,255,0.15);
    backdrop-filter: blur(10px);
    color: #fff;
    font-size: 0.92rem;
    font-weight: 600;
    padding: 14px 28px;
    border-radius: 50px;
    border: 1px solid rgba(255,255,255,0.3);
    transition: var(--transition);
}

.btn-secondary:hover {
    background: rgba(255,255,255,0.25);
    transform: translateY(-3px);
}

/* Scroll Indicator */
.hero-scroll-indicator {
    position: absolute;
    bottom: 28px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    color: rgba(255,255,255,0.6);
    font-size: 0.7rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    animation: fadeIn 1.5s ease 1.5s both;
}

.scroll-mouse {
    width: 22px;
    height: 34px;
    border: 2px solid rgba(255,255,255,0.5);
    border-radius: 12px;
    display: flex;
    align-items: flex-start;
    justify-content: center;
    padding-top: 5px;
}

.scroll-wheel {
    width: 3px;
    height: 8px;
    background: rgba(255,255,255,0.7);
    border-radius: 2px;
    animation: scrollWheel 2s ease-in-out infinite;
}

@keyframes scrollWheel {
    0%, 100% { transform: translateY(0); opacity: 1; }
    50% { transform: translateY(6px); opacity: 0.3; }
}

/* ==========================================
   SECTION COMMONS
   ========================================== */
.section { padding: 96px 0; }

.section.about { background: var(--bg-white); }
.section.career { background: var(--bg-light); }
.section.books { background: var(--bg-white); }
.section.lectures { background: var(--bg-light); }
.section.contact { background: var(--bg-white); }

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-badge {
    display: inline-block;
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: 0.15em;
    text-transform: uppercase;
    background: rgba(26, 86, 196, 0.08);
    padding: 6px 16px;
    border-radius: 50px;
    margin-bottom: 16px;
    border: 1px solid rgba(26, 86, 196, 0.15);
}

.section-title {
    font-family: 'Noto Serif KR', serif;
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    font-weight: 700;
    color: var(--text-dark);
    letter-spacing: -0.03em;
    margin-bottom: 12px;
    line-height: 1.3;
}

.section-subtitle {
    font-size: 1.05rem;
    color: var(--text-light);
    max-width: 500px;
    margin: 0 auto;
}

/* Animation Classes */
[data-animate] {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

[data-animate].animated {
    opacity: 1;
    transform: translateY(0);
}

/* ==========================================
   ABOUT SECTION
   ========================================== */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: start;
}

.about-intro {
    font-size: 1.15rem;
    font-weight: 500;
    color: var(--text-dark);
    line-height: 1.8;
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 2px solid var(--border-light);
}

.about-intro strong {
    color: var(--primary);
    font-weight: 700;
}

.about-desc {
    font-size: 0.97rem;
    color: var(--text-mid);
    line-height: 1.9;
    margin-bottom: 16px;
}

.about-keywords {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 24px;
}

.keyword {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--primary);
    background: rgba(26, 86, 196, 0.07);
    padding: 7px 14px;
    border-radius: 8px;
    border: 1px solid rgba(26, 86, 196, 0.12);
    transition: var(--transition);
}

.keyword:hover {
    background: rgba(26, 86, 196, 0.14);
    transform: translateY(-1px);
}

.keyword i {
    color: var(--accent-warm);
    font-size: 0.7rem;
}

/* Info Cards */
.about-cards {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.info-card {
    display: flex;
    gap: 14px;
    padding: 20px;
    background: var(--bg-light);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    transition: var(--transition);
}

.info-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-color: rgba(26, 86, 196, 0.2);
}

.card-icon {
    width: 44px;
    height: 44px;
    min-width: 44px;
    background: var(--gradient-card);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.1rem;
}

.card-content h4 {
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 4px;
}

.card-content p {
    font-size: 0.85rem;
    color: var(--text-mid);
    line-height: 1.6;
}

.card-content a {
    color: var(--primary);
    font-weight: 600;
}

.card-content a:hover { text-decoration: underline; }

/* ==========================================
   CAREER / TIMELINE SECTION
   ========================================== */
.timeline-wrapper {
    max-width: 800px;
    margin: 0 auto;
}

.timeline {
    position: relative;
    padding-left: 48px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 16px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(
        to bottom,
        var(--primary) 0%,
        var(--secondary) 50%,
        var(--accent) 100%
    );
    border-radius: 1px;
}

.timeline-item {
    position: relative;
    margin-bottom: 36px;
    animation: fadeInLeft 0.5s ease both;
}

.timeline-item:last-child { margin-bottom: 0; }

.timeline-marker {
    position: absolute;
    left: -40px;
    top: 20px;
    width: 20px;
    height: 20px;
    background: #fff;
    border: 3px solid var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.marker-dot {
    width: 8px;
    height: 8px;
    background: var(--primary);
    border-radius: 50%;
    animation: pulseDot 2s ease-in-out infinite;
}

@keyframes pulseDot {
    0%, 100% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.4); opacity: 0.6; }
}

.timeline-content {
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 24px 28px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    position: relative;
}

.timeline-content::before {
    content: '';
    position: absolute;
    left: -8px;
    top: 22px;
    width: 14px;
    height: 14px;
    background: var(--bg-white);
    border-left: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    transform: rotate(45deg);
}

.timeline-content:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
    border-color: rgba(26, 86, 196, 0.25);
}

.timeline-period {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--primary);
    background: rgba(26, 86, 196, 0.08);
    padding: 4px 12px;
    border-radius: 50px;
    margin-bottom: 10px;
    letter-spacing: 0.04em;
}

.timeline-period.current::after {
    content: ' • 재직중';
    color: #22c55e;
}

.timeline-title {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 4px;
    letter-spacing: -0.02em;
}

.timeline-role {
    font-size: 0.87rem;
    font-weight: 600;
    color: var(--primary-light);
    margin-bottom: 8px;
}

.timeline-desc {
    font-size: 0.87rem;
    color: var(--text-light);
    line-height: 1.6;
}

/* ==========================================
   BOOKS SECTION
   ========================================== */
.books-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.book-card {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border);
    transition: var(--transition);
    cursor: pointer;
}

.book-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.book-cover {
    position: relative;
    height: 200px;
    background: var(--gradient-card);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.book-cover.cover-2 { background: linear-gradient(135deg, #0ea5e9, #6366f1); }
.book-cover.cover-3 { background: linear-gradient(135deg, #0f766e, #0ea5e9); }
.book-cover.cover-4 { background: linear-gradient(135deg, #7c3aed, #ec4899); }
.book-cover.cover-5 { background: linear-gradient(135deg, #ea580c, #f59e0b); }
.book-cover.cover-6 { background: linear-gradient(135deg, #1e3a5f, #6366f1); }

.book-spine {
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 20px;
    background: rgba(0,0,0,0.2);
    border-right: 1px solid rgba(255,255,255,0.1);
}

.book-front {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.book-year {
    position: absolute;
    top: 12px;
    right: 14px;
    font-size: 0.7rem;
    font-weight: 700;
    color: rgba(255,255,255,0.7);
    letter-spacing: 0.08em;
}

.book-icon {
    font-size: 3rem;
    color: rgba(255,255,255,0.3);
    margin-bottom: 12px;
}

.book-title-overlay {
    font-family: 'Noto Serif KR', serif;
    font-size: 0.95rem;
    font-weight: 700;
    color: rgba(255,255,255,0.95);
    text-align: center;
    line-height: 1.4;
    text-shadow: 0 2px 8px rgba(0,0,0,0.3);
}

.book-info {
    padding: 20px 22px 24px;
}

.book-year-badge {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 700;
    color: var(--primary);
    background: rgba(26, 86, 196, 0.08);
    padding: 3px 10px;
    border-radius: 50px;
    margin-bottom: 10px;
    letter-spacing: 0.06em;
}

.book-name {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 8px;
    line-height: 1.4;
    letter-spacing: -0.02em;
}

.book-publisher {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 5px;
}

.book-desc {
    font-size: 0.82rem;
    color: var(--text-light);
    line-height: 1.6;
}

/* ==========================================
   LECTURES SECTION
   ========================================== */
.lecture-categories {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-bottom: 48px;
}

.lecture-category {
    background: var(--bg-white);
    border-radius: var(--radius-md);
    padding: 28px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    transition: var(--transition);
}

.lecture-category:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: rgba(26, 86, 196, 0.2);
}

.category-header {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 2px solid var(--border-light);
}

.category-icon {
    width: 48px;
    height: 48px;
    min-width: 48px;
    background: var(--gradient-main);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.1rem;
    box-shadow: 0 4px 12px rgba(26, 86, 196, 0.25);
}

.category-header h3 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-dark);
    line-height: 1.3;
    letter-spacing: -0.02em;
}

.lecture-list { display: flex; flex-direction: column; gap: 10px; }

.lecture-list li {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.88rem;
    color: var(--text-mid);
    padding: 6px 10px;
    border-radius: 8px;
    transition: var(--transition);
}

.lecture-list li:hover {
    background: rgba(26, 86, 196, 0.05);
    color: var(--primary);
    transform: translateX(4px);
}

.lecture-list li i {
    color: var(--primary);
    font-size: 0.65rem;
    min-width: 10px;
}

/* Highlight Quote */
.lecture-highlight {
    background: var(--gradient-main);
    border-radius: var(--radius-xl);
    padding: 48px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.lecture-highlight::before {
    content: '';
    position: absolute;
    inset: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Ccircle cx='30' cy='30' r='25'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.highlight-inner { position: relative; z-index: 1; }

.highlight-icon {
    font-size: 2.5rem;
    color: rgba(255,255,255,0.2);
    margin-bottom: 20px;
}

.highlight-text {
    font-family: 'Noto Serif KR', serif;
    font-size: clamp(1.1rem, 2.5vw, 1.4rem);
    color: rgba(255,255,255,0.95);
    line-height: 1.8;
    margin-bottom: 20px;
}

.highlight-text strong { color: var(--accent-warm); }

.highlight-name {
    font-size: 0.9rem;
    color: rgba(255,255,255,0.6);
    font-style: italic;
}

/* ==========================================
   CONTACT SECTION
   ========================================== */
.contact-wrapper {
    display: grid;
    grid-template-columns: 1fr 1.4fr;
    gap: 48px;
    align-items: start;
}

.contact-info-panel {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contact-item {
    display: flex;
    gap: 16px;
    padding: 22px;
    background: var(--bg-light);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    transition: var(--transition);
}

.contact-item:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
    border-color: rgba(26, 86, 196, 0.2);
}

.contact-icon {
    width: 48px;
    height: 48px;
    min-width: 48px;
    background: var(--gradient-main);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.1rem;
    box-shadow: 0 4px 12px rgba(26, 86, 196, 0.2);
}

.contact-details h4 {
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 6px;
}

.contact-details p {
    font-size: 0.92rem;
    color: var(--text-mid);
    line-height: 1.6;
}

.contact-link {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--primary);
    display: block;
    margin-bottom: 10px;
}

.contact-link:hover { text-decoration: underline; }

/* 이메일 바로 보내기 버튼 (contact-info 패널 내부) */
.btn-email-direct {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    background: var(--gradient-main);
    color: #fff;
    font-size: 0.82rem;
    font-weight: 700;
    padding: 8px 16px;
    border-radius: 50px;
    transition: var(--transition);
    box-shadow: 0 3px 10px rgba(26, 86, 196, 0.3);
}

.btn-email-direct:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 18px rgba(26, 86, 196, 0.4);
    color: #fff;
}

/* 폼 하단 직접 이메일 링크 */
.direct-email-wrap {
    margin-top: 18px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}

.direct-email-or {
    font-size: 0.78rem;
    color: var(--text-muted);
    font-weight: 500;
    position: relative;
    display: flex;
    align-items: center;
    gap: 10px;
    width: 100%;
    justify-content: center;
}

.direct-email-or::before,
.direct-email-or::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border);
}

.btn-email-plain {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 9px;
    width: 100%;
    padding: 13px 20px;
    background: #fff;
    border: 2px solid var(--primary);
    border-radius: 50px;
    color: var(--primary);
    font-size: 0.88rem;
    font-weight: 700;
    transition: var(--transition);
}

.btn-email-plain:hover {
    background: var(--primary);
    color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 6px 18px rgba(26, 86, 196, 0.3);
}

.btn-email-plain i {
    font-size: 1rem;
}

/* Contact Form */
.contact-form-panel {
    background: var(--bg-light);
    border-radius: var(--radius-lg);
    padding: 36px;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
}

.form-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 24px;
    letter-spacing: -0.02em;
    padding-bottom: 16px;
    border-bottom: 2px solid var(--border);
}

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

.form-group label {
    display: block;
    font-size: 0.82rem;
    font-weight: 700;
    color: var(--text-mid);
    margin-bottom: 7px;
    letter-spacing: 0.02em;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    font-family: 'Noto Sans KR', sans-serif;
    font-size: 0.9rem;
    color: var(--text-dark);
    background: var(--bg-white);
    transition: var(--transition);
    outline: none;
    resize: vertical;
    appearance: none;
    -webkit-appearance: none;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(26, 86, 196, 0.1);
}

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

.btn-submit {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    background: var(--gradient-main);
    color: #fff;
    font-family: 'Noto Sans KR', sans-serif;
    font-size: 0.95rem;
    font-weight: 700;
    padding: 15px 28px;
    border-radius: 50px;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 16px rgba(26, 86, 196, 0.3);
}

.btn-submit:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(26, 86, 196, 0.4);
}

.btn-submit:active { transform: translateY(0); }

/* ==========================================
   FOOTER
   ========================================== */
.footer {
    background: var(--text-dark);
    color: rgba(255,255,255,0.8);
    padding: 64px 0 0;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 48px;
    padding-bottom: 48px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-logo {
    font-family: 'Noto Serif KR', serif;
    font-size: 1.8rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 8px;
}

.footer-tagline {
    font-size: 0.85rem;
    color: rgba(255,255,255,0.5);
    margin-bottom: 16px;
}

.footer-email {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    color: rgba(255,255,255,0.6);
}

.footer-email i { color: var(--primary-light); }

.footer-email a {
    color: rgba(255,255,255,0.8);
    transition: var(--transition);
}

.footer-email a:hover { color: #fff; }

.footer-links h4,
.footer-expertise h4 {
    font-size: 0.78rem;
    font-weight: 700;
    color: rgba(255,255,255,0.4);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 16px;
}

.footer-links ul,
.footer-expertise ul {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.footer-links a {
    font-size: 0.87rem;
    color: rgba(255,255,255,0.6);
    transition: var(--transition);
}

.footer-links a:hover { color: #fff; padding-left: 4px; }

.footer-expertise li {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.87rem;
    color: rgba(255,255,255,0.6);
}

.footer-expertise i { color: var(--accent-warm); font-size: 0.75rem; }

.footer-bottom {
    padding: 20px 0;
    text-align: center;
}

.footer-bottom p {
    font-size: 0.8rem;
    color: rgba(255,255,255,0.3);
}

/* ==========================================
   BACK TO TOP BUTTON
   ========================================== */
.back-to-top {
    position: fixed;
    bottom: 28px;
    right: 28px;
    width: 48px;
    height: 48px;
    background: var(--gradient-main);
    color: #fff;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    box-shadow: 0 4px 16px rgba(26, 86, 196, 0.35);
    opacity: 0;
    transform: translateY(16px);
    transition: var(--transition);
    z-index: 900;
    pointer-events: none;
}

.back-to-top.visible {
    opacity: 1;
    transform: translateY(0);
    pointer-events: all;
}

.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 24px rgba(26, 86, 196, 0.45);
}

/* ==========================================
   KEYFRAME ANIMATIONS
   ========================================== */
@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInLeft {
    from { opacity: 0; transform: translateX(-20px); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* ==========================================
   SUCCESS MESSAGE
   ========================================== */
.form-success {
    display: none;
    text-align: center;
    padding: 32px;
}

.form-success.show { display: block; }

.success-icon {
    font-size: 3rem;
    color: #22c55e;
    margin-bottom: 16px;
}

.success-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 8px;
}

.success-msg {
    font-size: 0.9rem;
    color: var(--text-light);
}

/* ==========================================
   RESPONSIVE - TABLET (≤1024px)
   ========================================== */
@media (max-width: 1024px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .about-cards {
        grid-template-columns: repeat(2, 1fr);
    }

    .books-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .lecture-categories {
        grid-template-columns: repeat(2, 1fr);
    }

    .contact-wrapper {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr 1fr;
        gap: 32px;
    }

    .footer-brand { grid-column: 1 / -1; }
}

/* ==========================================
   RESPONSIVE - MOBILE (≤768px)
   ========================================== */
@media (max-width: 768px) {
    .section { padding: 72px 0; }

    /* Navbar Mobile */
    .hamburger { display: flex; }

    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: #fff;
        flex-direction: column;
        align-items: flex-start;
        padding: 80px 24px 40px;
        gap: 4px;
        transition: right 0.3s ease;
        box-shadow: -8px 0 32px rgba(0,0,0,0.12);
        z-index: 999;
    }

    .nav-links.open { right: 0; }

    .nav-link {
        color: var(--text-mid) !important;
        font-size: 1rem;
        width: 100%;
        padding: 12px 16px;
    }

    .nav-link:hover { background: var(--bg-light); }

    /* Hero Mobile */
    .hero { padding: 80px 20px 60px; }

    .hero-avatar {
        width: 110px;
        height: 110px;
    }

    .avatar-inner i { font-size: 2.5rem; }

    .hero-stats {
        padding: 18px 20px;
        gap: 0;
    }

    .stat-number { font-size: 1.8rem; }
    .stat-divider { margin: 0 12px; }

    /* Books Mobile */
    .books-grid {
        grid-template-columns: 1fr;
    }

    /* Lectures Mobile */
    .lecture-categories {
        grid-template-columns: 1fr;
    }

    .lecture-highlight { padding: 32px 24px; }

    /* About Mobile */
    .about-cards {
        grid-template-columns: 1fr;
    }

    /* Footer Mobile */
    .footer-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .footer-brand { grid-column: auto; }
}

/* ==========================================
   RESPONSIVE - SMALL MOBILE (≤480px)
   ========================================== */
@media (max-width: 480px) {
    .hero-tags { gap: 7px; }
    .tag { font-size: 0.77rem; padding: 6px 12px; }

    .hero-cta {
        flex-direction: column;
        align-items: center;
    }

    .btn-primary, .btn-secondary {
        width: 100%;
        justify-content: center;
    }

    .timeline { padding-left: 36px; }
    .timeline::before { left: 12px; }
    .timeline-marker { left: -32px; }

    .timeline-content { padding: 18px 20px; }

    .contact-form-panel { padding: 24px; }

    .lecture-highlight { padding: 28px 20px; }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 42px;
        height: 42px;
    }
}

/* ==========================================
   PRINT STYLES
   ========================================== */
@media print {
    .navbar, .hero-scroll-indicator, .back-to-top, .contact-form-panel { display: none; }
    .hero { min-height: auto; padding: 40px; }
    .section { padding: 40px 0; }
    * { box-shadow: none !important; }
}