/* Base Variables & Setup */
:root {
    --bg-dark: #09090b;
    --text-main: #f8fafc;
    --text-muted: #a1a1aa;
    
    --primary: #3b82f6;
    --primary-glow: rgba(59, 130, 246, 0.5);
    --secondary: #8b5cf6;
    --secondary-glow: rgba(139, 92, 246, 0.5);
    
    --glass-bg: rgba(24, 24, 27, 0.6);
    --glass-border: rgba(255, 255, 255, 0.08);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Background Effects */
.background-effects {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
}

.glow-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.4;
    animation: drift 20s infinite alternate ease-in-out;
}

.orb-1 {
    top: -10%;
    left: -10%;
    width: 50vw;
    height: 50vw;
    background: var(--primary);
}

.orb-2 {
    bottom: -10%;
    right: -10%;
    width: 60vw;
    height: 60vw;
    background: var(--secondary);
    animation-delay: -5s;
}

.orb-3 {
    top: 40%;
    left: 40%;
    width: 40vw;
    height: 40vw;
    background: #0ea5e9;
    opacity: 0.2;
    animation-delay: -10s;
}

@keyframes drift {
    0% { transform: translate(0, 0); }
    100% { transform: translate(10%, 10%); }
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    padding: 1.5rem 0;
    z-index: 100;
    transition: all 0.3s ease;
    border-bottom: 1px solid transparent;
}

.navbar.scrolled {
    padding: 1rem 0;
    background: rgba(9, 9, 11, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--glass-border);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-main);
    text-decoration: none;
    letter-spacing: -0.5px;
}

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

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s ease;
}

.nav-links a:hover {
    color: var(--text-main);
}

/* Common Layout */
main {
    padding-top: 80px;
}

.section {
    padding: 6rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(to right, #fff, #a1a1aa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

/* Hero Section */
.hero {
    min-height: calc(100vh - 80px);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.hero-content {
    text-align: center;
    max-width: 800px;
}

.profile-wrapper {
    margin-bottom: 2rem;
    display: inline-block;
}

.profile-image {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: linear-gradient(135deg, rgba(255,255,255,0.1), rgba(255,255,255,0.05));
    border: 1px solid var(--glass-border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    color: var(--primary);
    box-shadow: 0 0 40px var(--primary-glow);
    margin: 0 auto;
}

.badge {
    display: inline-block;
    padding: 0.5rem 1.2rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: 2rem;
    font-size: 0.9rem;
    color: var(--text-main);
    margin-bottom: 1.5rem;
    font-weight: 500;
}

.title {
    font-size: 4rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1rem;
    letter-spacing: -1px;
}

.title span {
    background: linear-gradient(to right, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    font-size: 1.5rem;
    color: var(--text-main);
    font-weight: 500;
    margin-bottom: 1.5rem;
}

.description {
    font-size: 1.1rem;
    color: var(--text-muted);
    margin-bottom: 3rem;
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.action-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.8rem 1.8rem;
    border-radius: 3rem;
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: all 0.3s ease;
}

.btn-primary {
    background: var(--text-main);
    color: var(--bg-dark);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(255, 255, 255, 0.2);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-main);
    border: 1px solid var(--glass-border);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
}

/* Glass Card Global */
.glass-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 1.5rem;
    padding: 2.5rem;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    transition: transform 0.3s ease, border-color 0.3s ease;
}

.glass-card:hover {
    transform: translateY(-5px);
    border-color: rgba(255, 255, 255, 0.2);
}

/* Interests Section */
.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.card-icon {
    width: 60px;
    height: 60px;
    border-radius: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    background: rgba(255, 255, 255, 0.05);
}

.card-icon.blue { color: #3b82f6; box-shadow: 0 0 20px rgba(59, 130, 246, 0.2); }
.card-icon.purple { color: #8b5cf6; box-shadow: 0 0 20px rgba(139, 92, 246, 0.2); }
.card-icon.green { color: #10b981; box-shadow: 0 0 20px rgba(16, 185, 129, 0.2); }

.glass-card h3 {
    font-size: 1.4rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.glass-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* Course Section */
.course-showcase {
    display: flex;
    align-items: flex-start;
    gap: 2.5rem;
    max-width: 900px;
    margin: 0 auto;
}

.course-icon {
    flex-shrink: 0;
    width: 80px;
    height: 80px;
    border-radius: 1.5rem;
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.2), rgba(139, 92, 246, 0.2));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    color: #fff;
    border: 1px solid rgba(255,255,255,0.1);
}

.course-details h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
}

.course-desc {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
}

.tags {
    display: flex;
    gap: 0.8rem;
    flex-wrap: wrap;
}

.tag {
    padding: 0.5rem 1.2rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: 2rem;
    font-size: 0.85rem;
    color: var(--text-main);
    font-weight: 500;
}

/* Contact Section */
.contact-section {
    padding-bottom: 8rem;
}

.contact-box {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.contact-box h2 {
    font-size: 2.2rem;
    margin-bottom: 1rem;
}

.contact-box > p {
    color: var(--text-muted);
    margin-bottom: 3rem;
    font-size: 1.1rem;
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    max-width: 500px;
    margin: 0 auto;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    padding: 1.5rem;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--glass-border);
    border-radius: 1rem;
    text-decoration: none;
    transition: all 0.3s ease;
}

.contact-link:hover {
    background: rgba(255, 255, 255, 0.08);
    transform: scale(1.02);
}

.contact-icon {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--text-main);
}

.contact-text {
    text-align: left;
}

.contact-text .label {
    display: block;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 0.2rem;
}

.contact-text .value {
    display: block;
    font-size: 1.1rem;
    color: var(--text-main);
    font-weight: 500;
}

/* Footer */
footer {
    text-align: center;
    padding: 3rem 2rem;
    border-top: 1px solid var(--glass-border);
    position: relative;
    z-index: 10;
}

footer p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.footer-sub {
    font-size: 0.85rem;
    margin-top: 0.5rem;
    opacity: 0.7;
}

/* Responsive Styles */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .title { font-size: 2.8rem; }
    .subtitle { font-size: 1.2rem; }
    
    .course-showcase {
        flex-direction: column;
        text-align: center;
        align-items: center;
    }
    
    .tags { justify-content: center; }
    
    .action-buttons {
        flex-direction: column;
    }
}