/* ==========================================
   CSS Variables & Reset
   ========================================== */

:root {
    /* Colors - Minimalist palette with subtle color accents */
    --color-primary: #0071e3;
    --color-primary-hover: #0077ed;
    --color-primary-light: #e8f4fd;
    --color-primary-border: rgba(0, 113, 227, 0.1);
    --color-accent: #f0f7ff;
    --color-accent-warm: #fff8f0;
    --color-accent-mint: #f0fff4;
    --color-text: #1d1d1f;
    --color-text-secondary: #86868b;
    --color-background: #ffffff;
    --color-background-alt: #f5f5f7;
    --color-background-tinted: #f8fafc;
    --color-border: #d2d2d7;
    --color-white: #ffffff;
    --color-black: #000000;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    --font-size-base: 17px;
    --font-size-xs: 11px;
    --font-size-sm: 14px;
    --font-size-lg: 21px;
    --font-size-xl: 28px;
    --font-size-2xl: 40px;
    --font-size-3xl: 56px;
    --font-size-4xl: 80px;
    
    /* Spacing */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 40px;
    --spacing-xl: 64px;
    --spacing-2xl: 96px;
    
    /* Layout */
    --container-max: 1200px;
    --navbar-height: 64px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.12);
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-full: 9999px;
}

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

html {
    scroll-behavior: smooth;
    font-size: var(--font-size-base);
}

body {
    font-family: var(--font-family);
    color: var(--color-text);
    background-color: var(--color-background);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

a:hover {
    color: var(--color-primary-hover);
}

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

ul {
    list-style: none;
}

/* ==========================================
   Layout & Container
   ========================================== */

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

section {
    padding: var(--spacing-2xl) 0;
}

/* ==========================================
   Typography
   ========================================== */

.section-title {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    letter-spacing: -0.02em;
    text-align: center;
    margin-bottom: var(--spacing-sm);
}

.section-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    text-align: center;
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ==========================================
   Buttons
   ========================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-base);
    font-weight: 500;
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: all var(--transition-base);
    border: none;
    text-decoration: none;
}

.btn-primary {
    background-color: var(--color-primary);
    color: var(--color-white);
}

.btn-primary:hover {
    background-color: var(--color-primary-hover);
    color: var(--color-white);
    transform: scale(1.02);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-primary);
    border: 1px solid var(--color-primary);
}

.btn-secondary:hover {
    background-color: var(--color-primary);
    color: var(--color-white);
}

.btn-outline {
    background-color: transparent;
    color: var(--color-text);
    border: 1px solid var(--color-border);
    padding: var(--spacing-sm) var(--spacing-lg);
}

.btn-outline:hover {
    border-color: var(--color-text);
    color: var(--color-text);
}

/* ==========================================
   Navigation
   ========================================== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--navbar-height);
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    z-index: 1000;
    transition: all var(--transition-base);
}

.navbar.scrolled {
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text);
}

.nav-logo:hover {
    color: var(--color-text);
}

.nav-menu {
    display: flex;
    gap: var(--spacing-lg);
}

.nav-link {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    font-weight: 500;
    transition: color var(--transition-fast);
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.nav-toggle .bar {
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    transition: all var(--transition-base);
}

/* ==========================================
   Hero Section
   ========================================== */

.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding-top: var(--navbar-height);
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-background) 50%, var(--color-accent-mint) 100%);
}

.hero-content {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: start;
}

.hero-intro {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.hero-profile {
    display: flex;
    justify-content: flex-start;
}

.profile-image-placeholder {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-border) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    border: 4px solid var(--color-white);
}

.profile-image-placeholder svg {
    width: 60%;
    height: 60%;
}

.profile-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
}

.hero-greeting {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xs);
}

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--color-text) 0%, var(--color-primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: var(--font-size-xl);
    color: var(--color-primary);
    font-weight: 500;
    margin-bottom: var(--spacing-md);
}

.hero-description {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    max-width: 500px;
    margin-bottom: var(--spacing-lg);
    line-height: 1.7;
}

.hero-social-links {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.hero-social-link {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-white);
    border-radius: 50%;
    color: var(--color-text);
    transition: all var(--transition-base);
    border: 1px solid var(--color-primary-border);
    box-shadow: var(--shadow-sm);
}

.hero-social-link:hover {
    background: var(--color-primary);
    color: var(--color-white);
    transform: scale(1.1);
}

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

.hero-social-link .cv-text-icon {
    font-size: 14px;
    font-weight: 700;
    letter-spacing: 0.5px;
}

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

/* Hero About Section (Right Side) */
.hero-about {
    background: var(--color-white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-primary-border);
}

.about-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
    position: relative;
    padding-bottom: var(--spacing-sm);
}

.about-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), transparent);
    border-radius: 2px;
}

.about-text {
    margin-bottom: var(--spacing-lg);
}

.about-lead {
    font-size: var(--font-size-base);
    font-weight: 500;
    line-height: 1.6;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.about-text p {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-secondary);
    line-height: 1.7;
    font-size: var(--font-size-sm);
}

/* News Section */
.news-section {
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-border);
}

.news-title {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
}

.news-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.news-item {
    display: flex;
    gap: var(--spacing-sm);
    padding: var(--spacing-xs) 0;
    font-size: var(--font-size-sm);
    line-height: 1.5;
    border-bottom: 1px solid var(--color-border);
}

.news-item:last-child {
    border-bottom: none;
}

.news-item.news-hidden {
    display: none;
}

.news-item.news-hidden.news-visible {
    display: flex;
}

.news-date {
    flex-shrink: 0;
    font-weight: 600;
    color: var(--color-primary);
    min-width: 70px;
}

.news-text {
    color: var(--color-text-secondary);
}

.news-expand-btn {
    margin-top: var(--spacing-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--font-size-sm);
    color: var(--color-primary);
    background: transparent;
    border: 1px solid var(--color-primary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.news-expand-btn:hover {
    background: var(--color-primary);
    color: var(--color-white);
}

.scroll-indicator {
    position: absolute;
    bottom: var(--spacing-lg);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    animation: bounce 2s infinite;
}

.scroll-arrow {
    width: 24px;
    height: 24px;
    border-right: 2px solid var(--color-text-secondary);
    border-bottom: 2px solid var(--color-text-secondary);
    transform: rotate(45deg);
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateX(-50%) translateY(0);
    }
    40% {
        transform: translateX(-50%) translateY(-10px);
    }
    60% {
        transform: translateX(-50%) translateY(-5px);
    }
}

/* ==========================================
   Publications Section
   ========================================== */

.publications {
    background: linear-gradient(180deg, var(--color-background) 0%, var(--color-accent) 100%);
}

.publications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.publication-card {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    display: flex;
    flex-direction: column;
}

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

.publication-image {
    width: 100%;
    height: 200px;
    overflow: hidden;
    background: linear-gradient(135deg, var(--color-background-alt) 0%, var(--color-border) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
}

.publication-image img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: var(--spacing-sm);
    box-sizing: border-box;
}

.publication-image-placeholder {
    width: 80px;
    height: 80px;
    opacity: 0.3;
}

.publication-content {
    padding: var(--spacing-md);
    flex: 1;
    display: flex;
    flex-direction: column;
}

.publication-venue {
    font-size: var(--font-size-sm);
    color: var(--color-primary);
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.publication-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.publication-authors {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
}

.publication-description {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: 1.6;
    flex: 1;
    margin-bottom: var(--spacing-sm);
}

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

.publication-link {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-primary);
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

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

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

/* ==========================================
   Contact Section
   ========================================== */

.contact {
    background: linear-gradient(180deg, var(--color-accent) 0%, var(--color-background) 100%);
}

.contact-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xl);
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
    width: 100%;
    max-width: 900px;
}

.contact-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: var(--spacing-lg);
    background: var(--color-white);
    border-radius: var(--radius-lg);
    transition: transform var(--transition-base);
    border: 1px solid var(--color-primary-border);
    box-shadow: var(--shadow-sm);
}

.contact-item:hover {
    transform: translateY(-4px);
}

.contact-icon {
    width: 48px;
    height: 48px;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.contact-icon svg {
    width: 100%;
    height: 100%;
}

.contact-details h3 {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.contact-details a,
.contact-details p {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.social-links {
    display: flex;
    gap: var(--spacing-md);
}

.social-link {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-white);
    border-radius: 50%;
    color: var(--color-text);
    transition: all var(--transition-base);
    border: 1px solid var(--color-primary-border);
    box-shadow: var(--shadow-sm);
}

.social-link:hover {
    background: var(--color-primary);
    color: var(--color-white);
    transform: scale(1.1);
}

.social-link svg {
    width: 24px;
    height: 24px;
}

.social-link .cv-text-icon {
    font-size: 16px;
    font-weight: 700;
    letter-spacing: 0.5px;
}

/* ==========================================
   Footer
   ========================================== */

.footer {
    background: var(--color-text);
    color: var(--color-background);
    padding: var(--spacing-lg) 0;
    text-align: center;
}

.footer p {
    font-size: var(--font-size-sm);
    opacity: 0.8;
}

.footer-note {
    margin-top: var(--spacing-xs);
    font-size: var(--font-size-sm);
    opacity: 0.5;
}

/* ==========================================
   Animations
   ========================================== */

.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ==========================================
   Responsive Design
   ========================================== */

@media (max-width: 1024px) {
    :root {
        --font-size-4xl: 56px;
        --font-size-3xl: 40px;
        --font-size-2xl: 32px;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }
    
    .hero-intro {
        text-align: center;
        align-items: center;
    }
    
    .hero-profile {
        justify-content: center;
    }
    
    .hero-description {
        margin-left: auto;
        margin-right: auto;
    }
    
    .hero-social-links {
        justify-content: center;
    }
    
    .hero-cta {
        justify-content: center;
    }
    
    .hero-about {
        max-width: 600px;
        margin: 0 auto;
    }
    
    .about-title::after {
        left: 50%;
        transform: translateX(-50%);
    }
    
    .news-item {
        flex-direction: column;
        gap: 2px;
    }
    
    .profile-image-placeholder {
        width: 180px;
        height: 180px;
    }
    
    .contact-info {
        grid-template-columns: 1fr;
        max-width: 400px;
    }
}

@media (max-width: 768px) {
    :root {
        --font-size-4xl: 40px;
        --font-size-3xl: 32px;
        --font-size-2xl: 28px;
        --font-size-xl: 21px;
        --spacing-2xl: 64px;
    }
    
    .nav-menu {
        position: fixed;
        top: var(--navbar-height);
        left: 0;
        right: 0;
        background: var(--color-white);
        flex-direction: column;
        padding: var(--spacing-md);
        gap: var(--spacing-sm);
        box-shadow: var(--shadow-md);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-base);
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .nav-toggle.active .bar:nth-child(1) {
        transform: translateY(7px) rotate(45deg);
    }
    
    .nav-toggle.active .bar:nth-child(2) {
        opacity: 0;
    }
    
    .nav-toggle.active .bar:nth-child(3) {
        transform: translateY(-7px) rotate(-45deg);
    }
    
    .publications-grid {
        grid-template-columns: 1fr;
    }
    
    .scroll-indicator {
        display: none;
    }
}

@media (max-width: 480px) {
    :root {
        --font-size-4xl: 32px;
        --font-size-3xl: 28px;
        --font-size-2xl: 24px;
    }
    
    .hero-cta {
        flex-direction: column;
        width: 100%;
    }
    
    .hero-cta .btn {
        width: 100%;
    }
    
    .profile-image-placeholder {
        width: 150px;
        height: 150px;
    }
    
    .social-links {
        flex-wrap: wrap;
        justify-content: center;
    }
}

/* ==========================================
   Accessibility
   ========================================== */

@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0s !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0s !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* Focus styles for accessibility */
a:focus,
button:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Skip link for accessibility */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-primary);
    color: var(--color-white);
    padding: var(--spacing-xs) var(--spacing-sm);
    z-index: 10000;
}

.skip-link:focus {
    top: 0;
}