:root {
    --bg-primary: #0a0e27;
    --bg-secondary: #141b3d;
    --bg-card: #1a2147;
    --text-primary: #e4e4e7;
    --text-secondary: #a1a1aa;
    --accent-cyan: #00d9ff;
    --accent-blue: #0080ff;
    --accent-purple: #7c3aed;
    --accent-green: #00ff88;
    --accent-pink: #ff00ff;
    --border-color: rgba(0, 217, 255, 0.2);
    --glow-color: rgba(0, 217, 255, 0.4);
}

[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f4f4f5;
    --bg-card: #fafafa;
    --text-primary: #18181b;
    --text-secondary: #52525b;
    --accent-cyan: #0891b2;
    --accent-blue: #2563eb;
    --accent-purple: #7c3aed;
    --accent-green: #059669;
    --accent-pink: #db2777;
    --border-color: rgba(8, 145, 178, 0.2);
    --glow-color: rgba(8, 145, 178, 0.3);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'JetBrains Mono', 'Courier New', monospace;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Matrix Canvas Background */
#matrix-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    opacity: 0.15;
    pointer-events: none;
}

/* Navigation */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(10, 14, 39, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 1.2rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: 'Space Mono', monospace;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent-cyan);
    display: flex;
    align-items: center;
    gap: 0.2rem;
}

.logo-bracket {
    color: var(--accent-green);
    font-size: 1.4rem;
}

.cursor-blink {
    animation: blink 1s infinite;
    color: var(--accent-cyan);
}

@keyframes blink {
    0%, 50% { opacity: 1; }
    51%, 100% { opacity: 0; }
}

.nav-menu {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    position: relative;
    padding: 0.5rem 0;
    transition: color 0.3s ease;
}

.nav-link::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent-cyan), var(--accent-blue));
    transition: width 0.3s ease;
}

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

.nav-link:hover::before,
.nav-link.active::before {
    width: 100%;
}

.theme-toggle {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    width: 40px;
    height: 40px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1.2rem;
}

.theme-toggle:hover {
    background: var(--bg-card);
    border-color: var(--accent-cyan);
    box-shadow: 0 0 20px var(--glow-color);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: transparent;
    border: none;
    cursor: pointer;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 2px;
    background: var(--accent-cyan);
    transition: all 0.3s ease;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 6rem 2rem 4rem;
    position: relative;
    overflow: hidden;
}

.hero-content {
    max-width: 1400px;
    width: 100%;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-glitch-wrapper {
    position: relative;
}

.hero-title {
    font-family: 'Space Mono', monospace;
    font-size: 4rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    animation: fadeInUp 0.8s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.glitch {
    position: relative;
}

.glitch::before,
.glitch::after {
    content: attr(data-text);
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: inherit;
    -webkit-background-clip: text;
    background-clip: text;
}

.glitch::before {
    left: 2px;
    text-shadow: -2px 0 var(--accent-pink);
    animation: glitch-anim 3s infinite linear alternate-reverse;
}

.glitch::after {
    left: -2px;
    text-shadow: 2px 0 var(--accent-cyan);
    animation: glitch-anim 2s infinite linear alternate;
}

@keyframes glitch-anim {
    0% { clip-path: inset(40% 0 61% 0); }
    20% { clip-path: inset(92% 0 1% 0); }
    40% { clip-path: inset(43% 0 1% 0); }
    60% { clip-path: inset(25% 0 58% 0); }
    80% { clip-path: inset(54% 0 7% 0); }
    100% { clip-path: inset(58% 0 43% 0); }
}

.hero-subtitle {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    animation: fadeInUp 0.8s ease-out 0.2s backwards;
}

.typing-text {
    font-family: 'Crimson Pro', serif;
    font-weight: 300;
}

.cursor {
    animation: blink 1s infinite;
    color: var(--accent-green);
}

.hero-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
    margin-bottom: 2.5rem;
    animation: fadeInUp 0.8s ease-out 0.4s backwards;
}

.tag {
    padding: 0.5rem 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.85rem;
    color: var(--accent-cyan);
    transition: all 0.3s ease;
}

.tag:hover {
    background: var(--accent-cyan);
    color: var(--bg-primary);
    box-shadow: 0 0 20px var(--glow-color);
    transform: translateY(-2px);
}

.hero-cta {
    display: flex;
    gap: 1rem;
    animation: fadeInUp 0.8s ease-out 0.6s backwards;
}

.btn {
    padding: 1rem 2rem;
    border-radius: 8px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
    color: var(--bg-primary);
    box-shadow: 0 4px 20px rgba(0, 217, 255, 0.3);
}

.btn-primary:hover {
    box-shadow: 0 8px 30px rgba(0, 217, 255, 0.5);
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    color: var(--accent-cyan);
    border: 2px solid var(--accent-cyan);
}

.btn-secondary:hover {
    background: var(--accent-cyan);
    color: var(--bg-primary);
    box-shadow: 0 0 20px var(--glow-color);
}

/* Neural Network Visualization */
.hero-visual {
    animation: fadeIn 1s ease-out 0.8s backwards;
}

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

.neural-network {
    width: 100%;
    height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.network-svg {
    width: 100%;
    height: 100%;
    filter: drop-shadow(0 0 20px var(--glow-color));
}

.node {
    fill: var(--bg-card);
    stroke-width: 2;
    animation: pulse 2s ease-in-out infinite;
}

.node-input {
    stroke: var(--accent-green);
}

.node-hidden {
    stroke: var(--accent-cyan);
    animation-delay: 0.5s;
}

.node-output {
    stroke: var(--accent-purple);
    animation-delay: 1s;
}

@keyframes pulse {
    0%, 100% { 
        opacity: 1;
        r: 8;
    }
    50% { 
        opacity: 0.6;
        r: 10;
    }
}

.connection {
    stroke: var(--accent-cyan);
    stroke-width: 1;
    opacity: 0.3;
    animation: flow 3s ease-in-out infinite;
}

@keyframes flow {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 0.6; }
}

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Section Common Styles */
section {
    padding: 6rem 0;
}

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

.section-title {
    font-size: 2.5rem;
    font-weight: 800;
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.section-number {
    font-family: 'Space Mono', monospace;
    color: var(--accent-cyan);
    font-size: 2rem;
}

.section-line {
    height: 2px;
    background: linear-gradient(90deg, var(--accent-cyan), transparent);
    animation: expandLine 1s ease-out;
}

@keyframes expandLine {
    from { width: 0; }
    to { width: 100%; }
}

/* Blog Section */
.blog-section {
    background: var(--bg-secondary);
}

.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
}

.blog-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    position: relative;
    transition: all 0.3s ease;
    overflow: hidden;
}

.blog-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-cyan), var(--accent-blue), var(--accent-purple));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.blog-card:hover::before {
    transform: scaleX(1);
}

.blog-card:hover {
    border-color: var(--accent-cyan);
    transform: translateY(-5px);
    box-shadow: 0 10px 40px rgba(0, 217, 255, 0.2);
}

.blog-card-glow {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, var(--glow-color), transparent);
    transform: translate(-50%, -50%);
    opacity: 0;
    transition: opacity 0.3s ease;
    pointer-events: none;
}

.blog-card:hover .blog-card-glow {
    opacity: 1;
}

.blog-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.blog-category {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--accent-cyan);
    font-weight: 600;
}

.blog-date {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-family: 'Space Mono', monospace;
}

.blog-title {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.3;
    color: var(--text-primary);
}

.blog-excerpt {
    font-family: 'Crimson Pro', serif;
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.blog-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.mini-tag {
    font-size: 0.75rem;
    padding: 0.3rem 0.6rem;
    background: rgba(0, 217, 255, 0.1);
    border: 1px solid rgba(0, 217, 255, 0.3);
    border-radius: 4px;
    color: var(--accent-cyan);
}

.blog-link {
    color: var(--accent-cyan);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.blog-link:hover {
    gap: 1rem;
}

.blog-link svg {
    transition: transform 0.3s ease;
}

.blog-link:hover svg {
    transform: translateX(5px);
}

/* Projects Section */
.projects-grid {
    display: flex;
    flex-direction: column;
    gap: 3rem;
}

.project-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 3rem;
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 2rem;
    align-items: center;
    position: relative;
    overflow: hidden;
    transition: all 0.3s ease;
}

.project-card::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: linear-gradient(180deg, var(--accent-cyan), var(--accent-purple));
    transform: scaleY(0);
    transition: transform 0.3s ease;
}

.project-card:hover::before {
    transform: scaleY(1);
}

.project-card:hover {
    border-color: var(--accent-cyan);
    box-shadow: 0 10px 40px rgba(0, 217, 255, 0.15);
}

.project-number {
    font-family: 'Space Mono', monospace;
    font-size: 3rem;
    font-weight: 800;
    color: var(--accent-cyan);
    opacity: 0.3;
}

.project-content {
    flex: 1;
}

.project-title {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.project-description {
    font-family: 'Crimson Pro', serif;
    font-size: 1.05rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
    margin-bottom: 1.5rem;
}

.tech-badge {
    padding: 0.4rem 0.8rem;
    background: rgba(124, 58, 237, 0.1);
    border: 1px solid rgba(124, 58, 237, 0.3);
    border-radius: 6px;
    font-size: 0.8rem;
    color: var(--accent-purple);
    font-weight: 600;
}

.project-links {
    display: flex;
    gap: 1rem;
}

.project-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--accent-cyan);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 600;
    transition: all 0.3s ease;
}

.project-link:hover {
    color: var(--accent-blue);
    gap: 0.8rem;
}

.project-visual {
    width: 200px;
    height: 200px;
}

.project-image-placeholder {
    width: 100%;
    height: 100%;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-cyan);
    transition: all 0.3s ease;
}
.project-image {
    width: 100%;
    height: 100%;
    object-fit: contain; /* cover | contain 선택 */
    border-radius: 8px;
  }
.project-img-semg {
    background-image: url("./images/project_snn_tcn_thumb.png");
  }
  .project-img-rag {
    background-image: url("./images/project_rag_thumb.png");
  }
  .project-img-robotics {
    background-image: url("./images/project_robotics_thumb.png");
  }
  .project-img-job-agent {
    background-image: url("./images/project_job_agent.png");
  }
  .project-img-worldmodel {
    background-image: url("./images/world_thumb.jpg");
  }

.project-card:hover .project-image-placeholder {
    border-color: var(--accent-cyan);
    box-shadow: 0 0 30px var(--glow-color);
}

/* About Section */
.about-section {
    background: var(--bg-secondary);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: start;
}

.about-text {
    font-family: 'Crimson Pro', serif;
}

.about-intro {
    font-size: 1.3rem;
    line-height: 1.8;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.about-description {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.skills-section {
    margin-bottom: 3rem;
}

.skills-title {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--accent-cyan);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
}

.skill-category h4 {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1rem;
    color: var(--accent-blue);
    margin-bottom: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.skill-category ul {
    list-style: none;
}

.skill-category li {
    font-family: 'Crimson Pro', serif;
    font-size: 1rem;
    color: var(--text-secondary);
    padding: 0.4rem 0;
    padding-left: 1rem;
    position: relative;
}

.skill-category li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--accent-cyan);
}

.contact-info {
    margin-top: 3rem;
}

.contact-title {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--accent-cyan);
}

.contact-links {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.95rem;
    transition: all 0.3s ease;
    padding: 0.5rem 0;
}

.contact-link:hover {
    color: var(--accent-cyan);
    transform: translateX(10px);
}

/* Terminal Window */
.terminal-window {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.terminal-header {
    background: var(--bg-card);
    padding: 0.8rem 1rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.terminal-buttons {
    display: flex;
    gap: 0.5rem;
}

.terminal-button {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.terminal-button.red {
    background: #ff5f57;
}

.terminal-button.yellow {
    background: #ffbd2e;
}

.terminal-button.green {
    background: #28ca42;
}

.terminal-title {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.terminal-body {
    padding: 2rem;
    font-size: 0.9rem;
    line-height: 1.8;
    overflow-x: auto;
}

.terminal-body code {
    color: var(--text-primary);
}

.code-keyword {
    color: #ff79c6;
}

.code-class {
    color: var(--accent-cyan);
}

.code-function {
    color: var(--accent-green);
}

.code-param {
    color: var(--accent-blue);
}

.code-string {
    color: #f1fa8c;
}

.code-comment {
    color: var(--text-secondary);
    font-style: italic;
}

/* Footer */
.footer {
    background: var(--bg-card);
    border-top: 1px solid var(--border-color);
    padding: 3rem 0;
    margin-top: 4rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.footer-text.small {
    font-size: 0.8rem;
    margin-top: 0.5rem;
}

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

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: var(--accent-cyan);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-title {
        font-size: 3rem;
    }
    
    .hero-cta {
        justify-content: center;
    }
    
    .hero-visual {
        order: -1;
    }
    
    .about-content {
        grid-template-columns: 1fr;
    }
    
    .project-card {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .project-visual {
        margin: 0 auto;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .blog-grid {
        grid-template-columns: 1fr;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 2rem;
        text-align: center;
    }
    
    .hero-tags {
        justify-content: center;
    }
}

/* Scroll animations */
@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.animate-on-scroll {
    opacity: 0;
    animation: fadeInUp 0.8s ease-out forwards;
}