/* ===================================
   CSS Custom Properties (Variables)
   =================================== */

:root {
    /* Colors - Light Mode */
    --color-bg: #ffffff;
    --color-bg-alt: #f8f9fa;
    --color-surface: #ffffff;
    --color-surface-hover: #f5f5f5;
    --color-text: #000000;
    --color-text-secondary: #404040;
    --color-text-tertiary: #666666;
    --color-accent: #000000;
    --color-accent-rgb: 0, 0, 0;
    --color-border: #e0e0e0;
    --color-silver: #c0c0c0;
    --color-silver-light: #e8e8e8;
    --color-silver-dark: #909090;
    
    /* Gradient */
    --gradient-primary: linear-gradient(135deg, #000000 0%, #606060 50%, #c0c0c0 100%);
    --gradient-silver: linear-gradient(135deg, #e8e8e8 0%, #c0c0c0 100%);
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Courier New', monospace;
    --font-handwritten: 'WindSong', cursive;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* Sizing */
    --max-width: 1400px;
    --max-width-text: 1200px;
    --container-padding: 10rem;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 300ms ease;
    --transition-slow: 500ms ease;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.16);
}

/* Dark Mode */
[data-theme="dark"] {
    --color-bg: #0a0a0a;
    --color-bg-alt: #141414;
    --color-surface: #1a1a1a;
    --color-surface-hover: #222222;
    --color-text: #ffffff;
    --color-text-secondary: #b0b0b0;
    --color-text-tertiary: #808080;
    --color-accent: #ffffff;
    --color-accent-rgb: 255, 255, 255;
    --color-border: #2a2a2a;
    --color-silver: #606060;
    --color-silver-light: #404040;
    --color-silver-dark: #808080;
    
    --gradient-primary: linear-gradient(135deg, #ffffff 0%, #a0a0a0 50%, #606060 100%);
    --gradient-silver: linear-gradient(135deg, #404040 0%, #606060 100%);
    
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
}

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

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    font-size: 15px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    overflow-x: hidden;
}

/* ===================================
   Typography
   =================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

h1 {
    font-size: clamp(2.3rem, 5vw, 3.7rem);
}

h2 {
    font-size: clamp(1.4rem, 3vw, 1.9rem);
}

h3 {
    font-size: clamp(1.1rem, 2.5vw, 1.4rem);
}

p {
    margin-bottom: 1rem;
}

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

/* ===================================
   Layout Components
   =================================== */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

.section {
    padding: var(--spacing-xl) 0;
    position: relative;
}

.section-alt {
    background-color: var(--color-bg-alt);
}

.section-title {
    margin-bottom: var(--spacing-lg);
    text-align: left;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: var(--gradient-primary);
    margin: var(--spacing-sm) 0 0;
}

/* ===================================
   Navigation
   =================================== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: var(--color-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid transparent;
    transition: all var(--transition-base);
}

.nav.scrolled {
    border-bottom-color: var(--color-border);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--spacing-sm) var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    font-family: var(--font-mono);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transition: all var(--transition-fast);
}

.nav-logo:hover {
    opacity: 0.7;
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
    list-style: none;
    align-items: center;
}

.nav-links a {
    font-size: 0.95rem;
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.nav-links a:hover {
    background-color: var(--color-surface);
    color: var(--color-accent);
}

.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.3rem;
    padding: 0.4rem;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background-color: var(--color-surface-hover);
    transform: rotate(20deg);
}

.theme-icon {
    display: block;
    line-height: 1;
}

/* ===================================
   Hero Section
   =================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    text-align: left;
    position: relative;
    padding: calc(var(--spacing-xl) + 4rem) 0 var(--spacing-xl);
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 50%, rgba(192, 192, 192, 0.1) 0%, transparent 50%);
    pointer-events: none;
}

.hero-title {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.hero-subtitle {
    font-size: clamp(1.2rem, 2.5vw, 1.8rem);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xs);
    font-weight: 300;
}

.hero-subtitle-secondary {
    font-size: clamp(1rem, 2vw, 1.3rem);
    color: var(--color-text-tertiary);
    margin-bottom: var(--spacing-md);
    font-weight: 300;
    font-style: italic;
}

.hero-description {
    font-size: clamp(1rem, 2vw, 1.2rem);
    color: var(--color-text-tertiary);
    max-width: 1100px;
    margin: 0 0 var(--spacing-lg);
}

.hero-cta {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: flex-start;
    flex-wrap: wrap;
}

/* ===================================
   Buttons
   =================================== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.875rem 2rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

.btn-primary {
    background-color: var(--color-accent);
    color: #ffffff;
    border-color: var(--color-accent);
}

.btn-primary:hover {
    background: var(--gradient-primary);
    color: #ffffff;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(var(--color-accent-rgb), 0.2);
}

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

.btn-secondary:hover {
    background-color: var(--color-accent);
    color: #ffffff;
    transform: translateY(-2px);
}

/* ===================================
   Publications Section
   =================================== */
.publications-list {
    max-width: var(--max-width-text);
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.publication {
    background-color: var(--color-surface);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    border: 2px solid var(--color-silver-light);
    transition: all var(--transition-base);
    opacity: 0;
    transform: translateY(20px);
}

.publication.fade-in {
    opacity: 1;
    transform: translateY(0);
}

.publication:hover {
    border-color: var(--color-accent);
    box-shadow: var(--shadow-md);
    background: var(--gradient-silver);
}

.publication-custom-title {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
}

.publication-official-title {
    font-size: 0.95rem;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: var(--color-text-secondary);
}

.publication-venue {
    color: var(--color-text-tertiary);
    font-size: 0.85rem;
    margin-bottom: var(--spacing-sm);
    font-style: italic;
}

.presentation-type {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.15rem 0.4rem;
    border-radius: var(--radius-sm);
    font-size: 0.7rem;
    font-weight: 600;
    font-style: normal;
    margin-right: 0.5rem;
    border: 1.5px solid;
}

.presentation-type.oral {
    color: #2563eb;
    border-color: #2563eb;
    background-color: rgba(37, 99, 235, 0.05);
}

.presentation-type.poster {
    color: #059669;
    border-color: #059669;
    background-color: rgba(5, 150, 105, 0.05);
}

.publication-links {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.pub-link {
    padding: 0.4rem 1rem;
    background-color: var(--color-surface);
    border: 1px solid var(--color-silver);
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    transition: all var(--transition-fast);
}

.pub-link:hover {
    border-color: var(--color-accent);
    background-color: var(--color-accent);
    color: var(--color-bg);
}

/* ===================================
   Contact Section
   =================================== */
.contact-content {
    max-width: 600px;
    margin: 0;
    text-align: left;
}

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

.contact-links {
    display: flex;
    justify-content: flex-start;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.contact-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: var(--color-surface);
    border: 2px solid var(--color-silver);
    border-radius: var(--radius-md);
    font-weight: 500;
    transition: all var(--transition-base);
}

.contact-link:hover {
    border-color: var(--color-accent);
    background-color: var(--color-accent);
    color: var(--color-bg);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.contact-link:hover svg {
    stroke: var(--color-bg);
}

.contact-link svg {
    width: 20px;
    height: 20px;
}

/* ===================================
   Footer
   =================================== */
.footer {
    background-color: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-md) 0;
    text-align: left;
    color: var(--color-text-tertiary);
}

.footer p {
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

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

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 768px) {
    :root {
        --container-padding: 4rem;
    }
    
    .nav-links {
        gap: var(--spacing-sm);
    }
    
    .nav-links a {
        font-size: 0.85rem;
        padding: var(--spacing-xs);
    }
    
    .hero {
        min-height: 90vh;
    }
    
    .section {
        padding: var(--spacing-lg) 0;
    }
    
    .featured-projects-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .featured-project-image {
        aspect-ratio: 16 / 9;
    }
    
    .contact-links {
        flex-direction: column;
        align-items: stretch;
    }
    
    .hero-projects-title {
        font-size: 1.3rem;
    }
    
    .publication {
        padding: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    :root {
        --container-padding: 2rem;
    }
    
    body {
        font-size: 14px;
    }
    
    .nav-container {
        padding: var(--spacing-sm);
    }
    
    .nav-logo {
        font-size: 1.2rem;
    }
    
    .nav-links {
        gap: var(--spacing-xs);
    }
    
    .nav-links a {
        padding: 0.3rem 0.5rem;
        font-size: 0.8rem;
    }
    
    .theme-toggle {
        font-size: 1.1rem;
        padding: 0.3rem;
    }
    
    .container {
        padding: var(--container-padding);
    }
    
    .hero-description {
        font-size: 0.95rem;
    }
    
    .featured-project-content {
        padding: var(--spacing-sm);
    }
    
    .featured-project-title {
        font-size: 1.1rem;
    }
    
    .featured-project-description {
        font-size: 0.85rem;
    }
    
    .competition-name {
        font-size: 0.65rem;
    }
    
    .featured-tag {
        font-size: 0.65rem;
        padding: 0.15rem 0.4rem;
    }
    
    .award-badge {
        font-size: 0.6rem;
        padding: 0.15rem 0.4rem;
    }
    
    .release-date {
        font-size: 0.7rem;
    }
    
    .publication-custom-title {
        font-size: 1rem;
    }
    
    .publication-official-title {
        font-size: 0.85rem;
    }
    
    .publication-venue {
        font-size: 0.75rem;
    }
    
    .presentation-type {
        font-size: 0.65rem;
        padding: 0.1rem 0.3rem;
    }
    
    .pub-link {
        font-size: 0.8rem;
        padding: 0.3rem 0.8rem;
    }
    
    .contact-link {
        padding: var(--spacing-sm);
        font-size: 0.9rem;
    }
}

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

.fade-in {
    animation: fadeInUp 0.6s ease forwards;
}

/* ===================================
   Accessibility
   =================================== */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* ===================================
   Featured Projects on Hero
   =================================== */
.hero-projects {
    margin-top: var(--spacing-lg);
    max-width: 100%;
    margin-left: auto;
    margin-right: auto;
}

.hero-projects-title {
    font-size: 1rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-tertiary);
    margin-bottom: var(--spacing-md);
    text-align: left;
}

.featured-projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-md);
}

.featured-project {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 2px solid var(--color-silver-light);
    transition: all var(--transition-base);
    text-align: left;
    cursor: pointer;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.featured-project:hover {
    border-color: var(--color-accent);
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.featured-project-image {
    width: 100%;
    aspect-ratio: 24 / 9;
    overflow: hidden;
    background-color: var(--color-surface);
    display: flex;
    align-items: center;
    justify-content: center;
}

.featured-project-image img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    transition: transform var(--transition-base);
}

.featured-project:hover .featured-project-image img {
    transform: scale(1.05);
}

.featured-project-content {
    padding: var(--spacing-sm) var(--spacing-md);
}

.featured-project-header {
    margin-bottom: var(--spacing-sm);
}

.featured-project-meta,
.featured-project-competition {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.competition-name {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-silver-dark);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.featured-project-awards {
    display: flex;
    gap: 0.4rem;
    flex-wrap: wrap;
}

.award-badge {
    padding: 0.2rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.65rem;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    border: 1.5px solid;
    background-color: var(--color-surface);
    transition: all var(--transition-fast);
}

.award-badge.bronze {
    color: #cd7f32;
    border-color: #cd7f32;
}

.award-badge.silver {
    color: #c0c0c0;
    border-color: #a8a8a8;
}

.award-badge.oral {
    color: #2563eb;
    border-color: #2563eb;
}

.award-badge.poster {
    color: #059669;
    border-color: #059669;
}

.featured-project:hover .award-badge.bronze {
    background-color: #cd7f32;
    color: #ffffff;
}

.featured-project:hover .award-badge.silver {
    background-color: #c0c0c0;
    color: #000000;
}

.featured-project:hover .award-badge.oral {
    background-color: #2563eb;
    color: #ffffff;
}

.featured-project:hover .award-badge.poster {
    background-color: #059669;
    color: #ffffff;
}

.featured-project-year {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-silver-dark);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-xs);
}

.featured-project-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.featured-project-description {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
    margin-bottom: var(--spacing-sm);
}

.featured-project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}

.featured-tag {
    padding: 0.2rem 0.6rem;
    background-color: var(--color-silver-light);
    border: 1px solid var(--color-silver);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-family: var(--font-mono);
    color: var(--color-text-secondary);
    transition: all var(--transition-fast);
}

.featured-project:hover .featured-tag {
    border-color: var(--color-accent);
    background-color: var(--color-accent);
    color: var(--color-bg);
}

.featured-project-release {
    margin-top: var(--spacing-sm);
}

.release-date {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--color-silver-dark);
    font-style: italic;
}

/* ===================================
   Print Styles
   =================================== */
@media print {
    .nav,
    .contact-links {
        display: none;
    }
    
    body {
        background-color: white;
        color: black;
    }
}