/* ===== CSS Variables & Design Tokens ===== */
:root {
    /* Colors */
    --color-bg: #000000;
    --color-bg-secondary: #0a0a0a;
    --color-bg-card: rgba(20, 20, 20, 0.6);
    --color-text-primary: #ffffff;
    --color-text-secondary: #a0a0a0;
    --color-accent: #6366f1;
    --color-accent-hover: #818cf8;
    --color-gradient-start: #6366f1;
    --color-gradient-end: #8b5cf6;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 0.75rem;
    --spacing-lg: 1rem;
    --spacing-xl: 1.5rem;
    --spacing-2xl: 2rem;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-base: 16px;
    --font-size-sm: 0.875rem;
    --font-size-md: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    --font-size-3xl: 3rem;
    --font-size-4xl: 4rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(99, 102, 241, 0.1);
    --shadow-md: 0 4px 16px rgba(99, 102, 241, 0.15);
    --shadow-lg: 0 8px 32px rgba(99, 102, 241, 0.2);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.3);
}

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

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

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

/* ===== Grain Overlay Effect ===== */
.grain-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 400 400' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)' opacity='0.03'/%3E%3C/svg%3E");
    pointer-events: none;
    z-index: 1;
    opacity: 0.5;
}

/* ===== Container ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg);
    position: relative;
    z-index: 2;
}

/* ===== Header =====*/
.header {
    min-height: 60vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
}

.header-content {
    animation: fadeInUp 1s ease-out;
}

.greeting {
    display: block;
    font-size: var(--font-size-lg);
    font-weight: 400;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
    animation: fadeIn 1s ease-out 0.2s both;
}

.name-title {
    margin-bottom: var(--spacing-md);
}

.name {
    display: block;
    font-size: clamp(2.5rem, 8vw, 5rem);
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradientShift 3s ease infinite, fadeIn 1s ease-out 0.4s both;
    background-size: 200% 200%;
}

.tagline {
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
    font-weight: 300;
    animation: fadeIn 1s ease-out 0.6s both;
    margin-bottom: var(--spacing-sm);
}

.subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    font-weight: 300;
    animation: fadeIn 1s ease-out 0.8s both;
}

/* ===== Sections =====*/
.section {
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-md) 0;
    animation: fadeInUp 0.8s ease-out;
}

.section-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--color-gradient-start), var(--color-gradient-end));
    border-radius: 2px;
}

/* ===== About Section ===== */
.about-content {
    max-width: 800px;
}

.about-text {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

/* ===== Skills Section ===== */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.skill-card {
    background: var(--color-bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    transition: all var(--transition-base);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.skill-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(139, 92, 246, 0.1));
    opacity: 0;
    transition: opacity var(--transition-base);
}

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

.skill-card:hover::before {
    opacity: 1;
}

.skill-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    position: relative;
    z-index: 1;
}

.skill-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    position: relative;
    z-index: 1;
}

.skill-description {
    color: var(--color-text-secondary);
    line-height: 1.6;
    position: relative;
    z-index: 1;
}

/* ===== Interests Section ===== */
.interests-content {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-sm);
}

.interest-tag {
    background: var(--color-bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(99, 102, 241, 0.2);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 2rem;
    font-size: var(--font-size-md);
    color: var(--color-text-primary);
    transition: all var(--transition-base);
    cursor: pointer;
}

.interest-tag:hover {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.2), rgba(139, 92, 246, 0.2));
    border-color: var(--color-accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ===== Work Experience Section ===== */
.timeline {
    position: relative;
    padding-left: var(--spacing-xl);
    margin-top: var(--spacing-sm);
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, var(--color-accent), rgba(99, 102, 241, 0.2));
}

.timeline-item {
    position: relative;
    margin-bottom: var(--spacing-lg);
    padding-left: var(--spacing-lg);
}

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

.timeline-marker {
    position: absolute;
    left: -6px;
    top: 4px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--color-accent);
    border: 3px solid var(--color-bg-primary);
    box-shadow: 0 0 0 2px var(--color-accent);
    transition: all var(--transition-base);
}

.timeline-item:hover .timeline-marker {
    transform: scale(1.3);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.3);
}

.timeline-content {
    background: var(--color-bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-sm);
    padding: var(--spacing-md);
    transition: all var(--transition-base);
}

.timeline-item:hover .timeline-content {
    border-color: var(--color-accent);
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
}

.job-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text-primary);
    margin: 0 0 var(--spacing-xs) 0;
}

.company-name {
    font-size: var(--font-size-md);
    color: var(--color-accent);
    font-weight: 500;
    margin: 0 0 var(--spacing-xs) 0;
}

.job-duration {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin: 0 0 var(--spacing-xs) 0;
}

.job-location {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    opacity: 0.8;
    margin: 0;
}

/* ===== Publications Section ===== */
.publications-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-top: var(--spacing-sm);
}

.publication-item {
    background: var(--color-bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-sm);
    padding: var(--spacing-md);
    transition: all var(--transition-base);
}

.publication-item:hover {
    border-color: var(--color-accent);
    transform: translateX(8px);
    box-shadow: var(--shadow-md);
}

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

.publication-venue {
    font-size: var(--font-size-md);
    color: var(--color-accent);
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
}

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

.publication-link {
    display: inline-flex;
    align-items: center;
    color: var(--color-accent-hover);
    text-decoration: none;
    font-size: var(--font-size-sm);
    font-weight: 500;
    transition: all var(--transition-fast);
}

.publication-link:hover {
    color: var(--color-text-primary);
    transform: translateX(4px);
}

/* ===== Patents Section ===== */
.patents-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
}

.patent-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
    background: var(--color-bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-sm);
    padding: var(--spacing-md);
    transition: all var(--transition-base);
}

.patent-item:hover {
    border-color: var(--color-accent);
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
}

.patent-number {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-accent);
    flex-shrink: 0;
    min-width: 2rem;
}

.patent-text {
    color: var(--color-text-secondary);
    line-height: 1.6;
    margin: 0;
}

/* ===== Achievements Section ===== */
.achievements-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
}

.achievement-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
    background: var(--color-bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-sm);
    padding: var(--spacing-md);
    transition: all var(--transition-base);
}

.achievement-item:hover {
    border-color: var(--color-accent);
    transform: translateX(8px);
    box-shadow: var(--shadow-md);
}

.achievement-icon {
    font-size: 2rem;
    flex-shrink: 0;
}

.achievement-text {
    color: var(--color-text-secondary);
    line-height: 1.6;
    margin: 0;
}

.achievement-text .inline-link {
    color: var(--color-accent);
    text-decoration: none;
    font-weight: 500;
    transition: all var(--transition-base);
    border-bottom: 1px solid transparent;
}

.achievement-text .inline-link:hover {
    color: var(--color-text-primary);
    border-bottom-color: var(--color-accent);
}

/* ===== Invited Talks Section ===== */
.talks-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-top: var(--spacing-sm);
}

.talk-item {
    background: var(--color-bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-sm);
    padding: var(--spacing-md);
    transition: all var(--transition-base);
}

.talk-item:hover {
    border-color: var(--color-accent);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.talk-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text-primary);
    margin: 0 0 var(--spacing-xs) 0;
}

.talk-venue {
    font-size: var(--font-size-sm);
    color: var(--color-accent);
    margin: 0 0 var(--spacing-xs) 0;
    font-weight: 500;
}

.talk-description {
    color: var(--color-text-secondary);
    line-height: 1.6;
    margin: 0 0 var(--spacing-sm) 0;
}

.talk-link {
    display: inline-block;
    color: var(--color-accent);
    text-decoration: none;
    font-weight: 500;
    transition: all var(--transition-base);
}

.talk-link:hover {
    color: var(--color-text-primary);
    transform: translateX(4px);
}

.talk-link::after {
    content: '';
    display: block;
    width: 0;
    height: 2px;
    background: var(--color-accent);
    transition: width var(--transition-base);
}

.talk-link:hover::after {
    width: 100%;
}

/* ===== Blogs Section ===== */
.blogs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-sm);
}

.blog-card {
    background: var(--color-bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-sm);
    padding: var(--spacing-md);
    text-decoration: none;
    color: var(--color-text-primary);
    transition: all var(--transition-base);
    display: block;
}

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

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

.blog-description {
    color: var(--color-text-secondary);
    line-height: 1.6;
    font-size: var(--font-size-md);
}

/* ===== Contact Section ===== */
.contact-section {
    text-align: center;
}

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

.social-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.social-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background: var(--color-bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(99, 102, 241, 0.2);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--color-text-primary);
    font-size: var(--font-size-lg);
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.social-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(99, 102, 241, 0.3), transparent);
    transition: left var(--transition-slow);
}

.social-link:hover::before {
    left: 100%;
}

.social-link:hover {
    border-color: var(--color-accent);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.social-icon {
    font-size: 1.5rem;
}

.social-text {
    font-weight: 500;
}

/* ===== Footer ===== */
.footer {
    text-align: center;
    padding: var(--spacing-xl) 0;
    border-top: 1px solid rgba(99, 102, 241, 0.1);
    margin-top: var(--spacing-2xl);
}

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

/* ===== Animations ===== */
@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes gradientShift {
    0% {
        background-position: 0% 50%;
    }

    50% {
        background-position: 100% 50%;
    }

    100% {
        background-position: 0% 50%;
    }
}

/* ===== Responsive Design ===== */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md);
    }

    .section {
        padding: var(--spacing-lg) 0;
    }

    .section-title {
        font-size: var(--font-size-xl);
    }

    .skills-grid {
        grid-template-columns: 1fr;
    }

    .blogs-grid {
        grid-template-columns: 1fr;
    }

    .social-links {
        flex-direction: column;
        align-items: stretch;
    }

    .social-link {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .tagline {
        font-size: var(--font-size-lg);
    }

    .about-text {
        font-size: var(--font-size-md);
    }
}