/* CSS Variables & Design System */
:root {
    /* Colors - FinTech Slate/Navy Theme */
    --color-primary: #0f172a;
    /* Slate 900 */
    --color-secondary: #334155;
    /* Slate 700 */
    --color-accent: #0ea5e9;
    /* Sky 500 */
    --color-accent-hover: #0284c7;
    /* Sky 600 */
    --color-text-main: #1e293b;
    /* Slate 800 */
    --color-text-light: #64748b;
    /* Slate 500 */
    --color-background: #ffffff;
    --color-background-alt: #f8fafc;
    /* Slate 50 */
    --color-border: #e2e8f0;
    /* Slate 200 */

    /* Typography */
    --font-primary: 'Inter', sans-serif;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 4rem;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;

    /* Layout */
    --container-width: 1200px;
    --header-height: 70px;
    --border-radius: 8px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    color: var(--color-text-main);
    line-height: 1.6;
    background-color: var(--color-background);
}

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

ul {
    list-style: none;
}

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

/* Utilities */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

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

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

.mt-4 {
    margin-top: var(--spacing-lg);
}

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

/* Buttons */
.btn-primary,
.btn-secondary {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    font-weight: 500;
    cursor: pointer;
    font-size: var(--text-base);
    transition: all var(--transition-fast);
}

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

.btn-primary:hover {
    background-color: var(--color-secondary);
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: transparent;
    border: 2px solid var(--color-primary);
    color: var(--color-primary);
    margin-left: var(--spacing-sm);
}

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

/* Badges */
.badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background-color: rgba(14, 165, 233, 0.1);
    color: var(--color-accent);
    border-radius: 999px;
    font-size: var(--text-sm);
    font-weight: 600;
    margin-right: 0.5rem;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    display: flex;
    align-items: center;
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--color-primary);
}

.highlight {
    color: var(--color-accent);
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

.nav-links a {
    font-weight: 500;
    font-size: var(--text-sm);
    color: var(--color-text-main);
}

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

.nav-links a.btn-primary {
    color: white;
    padding: 0.5rem 1rem;
    font-size: var(--text-sm);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--color-text-main);
}

.mobile-nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    width: 100%;
    background: white;
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md);
    flex-direction: column;
    gap: var(--spacing-sm);
}

.mobile-nav.active {
    display: flex;
}

/* Hero Section */
.hero {
    height: 100vh;
    min-height: 600px;
    display: flex;
    align-items: center;
    padding-top: var(--header-height);
    position: relative;
    background: linear-gradient(135deg, var(--color-background-alt) 0%, #fff 100%);
}

.hero h1 {
    font-size: var(--text-4xl);
    font-weight: 800;
    color: var(--color-primary);
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

.hero .subtitle {
    font-size: var(--text-xl);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
    max-width: 600px;
}

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

.social-links a {
    font-size: 1.5rem;
    color: var(--color-text-light);
}

.social-links a:hover {
    color: var(--color-accent);
    transform: translateY(-2px);
}

/* Sections */
.section {
    padding: 80px 0;
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 3rem;
    position: relative;
    padding-bottom: 1rem;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 4px;
    background-color: var(--color-accent);
    border-radius: 2px;
}

.text-center .section-title::after {
    left: 50%;
    transform: translateX(-50%);
}

.section-subtitle {
    color: var(--color-text-light);
    margin-bottom: 2rem;
}

/* About Grid */
.about-grid {
    display: grid;
    grid-template-columns: 3fr 2fr;
    gap: var(--spacing-xl);
    align-items: center;
}

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

.highlights-list {
    margin-top: var(--spacing-md);
}

.highlights-list li {
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
}

.highlights-list i {
    color: var(--color-accent);
}

.image-placeholder {
    width: 100%;
    aspect-ratio: 1;
    background-color: var(--color-background-alt);
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 5rem;
    color: var(--color-border);
    border: 2px dashed var(--color-border);
}

/* Experience Timeline */
.timeline {
    position: relative;
    border-left: 2px solid var(--color-border);
    margin-left: 1rem;
    padding-left: 2rem;
}

.timeline-item {
    margin-bottom: 3rem;
    position: relative;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -2.6rem;
    top: 5px;
    width: 1rem;
    height: 1rem;
    background-color: var(--color-accent);
    border-radius: 50%;
    border: 3px solid white;
}

.role-header {
    margin-bottom: 1rem;
}

.role-header h3 {
    font-size: var(--text-xl);
    color: var(--color-primary);
}

.role-header .company {
    display: block;
    font-weight: 600;
    color: var(--color-secondary);
}

.role-header .date {
    display: block;
    font-size: var(--text-sm);
    color: var(--color-text-light);
    margin-top: 0.25rem;
}

.timeline-content p {
    color: var(--color-text-main);
    margin-bottom: 1rem;
}

.subsection-title {
    font-size: var(--text-base);
    font-weight: 700;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
    color: var(--color-secondary);
}

.role-details {
    margin-bottom: 0.5rem;
}

.role-details li {
    margin-bottom: 0.5rem;
    list-style-type: disc;
    margin-left: 1.5rem;
    color: var(--color-text-main);
}

ol.role-details li {
    list-style-type: decimal;
}

/* Expertise Grid */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.card {
    background: white;
    padding: 2rem;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    transition: var(--transition-medium);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    border-color: var(--color-accent);
}

.card-icon {
    font-size: 2rem;
    color: var(--color-accent);
    margin-bottom: 1rem;
}

.card h3 {
    margin-bottom: 0.75rem;
    font-size: 1.25rem;
}

/* Publications */
.publication-list {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.pub-item {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
}

.pub-badges {
    margin-bottom: 1rem;
}

.pub-item h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.pub-item .venue {
    font-style: italic;
    color: var(--color-text-light);
    margin-bottom: 1rem;
}

.link-arrow {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    color: var(--color-accent);
    margin-top: 1rem;
}

.link-arrow:hover {
    gap: 0.75rem;
}

/* Publication Placeholder */
.publication-placeholder {
    padding: 2rem;
    display: flex;
    justify-content: center;
}

.publication-placeholder img {
    width: 100%;
    height: 300px;
    object-fit: cover;
    object-position: center;
}

.img-fluid {
    max-width: 100%;
    height: auto;
}

.rounded {
    border-radius: var(--border-radius);
}

.shadow-sm {
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

/* Grid 2 */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
}

.membership-card {
    border: 1px solid var(--color-border);
    padding: 2rem;
    border-radius: var(--border-radius);
    background: white;
    transition: var(--transition-medium);
}

.membership-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
}

.membership-card h3 {
    color: var(--color-primary);
    margin-bottom: 0.75rem;
    font-size: 1.25rem;
}

.membership-card p {
    color: var(--color-text-light);
    font-size: var(--text-base);
}

/* Contact Form */
.contact-wrapper {
    max-width: 700px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    font-size: var(--text-sm);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    font-family: inherit;
    font-size: var(--text-base);
    transition: var(--transition-fast);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.1);
}

/* Footer */
footer {
    background-color: var(--color-primary);
    color: white;
    padding: 3rem 0;
    margin-top: 4rem;
}

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

.footer-social {
    display: flex;
    gap: 1.5rem;
}

.footer-social a {
    color: rgba(255, 255, 255, 0.7);
}

.footer-social a:hover {
    color: white;
}

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

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

.delay-1 {
    transition-delay: 0.1s;
}

.delay-2 {
    transition-delay: 0.2s;
}

/* Responsive */
@media (max-width: 768px) {
    :root {
        --text-4xl: 2.5rem;
    }

    .nav-links {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .hero {
        text-align: center;
        padding-top: 100px;
    }

    .hero-actions {
        justify-content: center;
    }

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

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

    .grid-2 {
        grid-template-columns: 1fr;
    }

    .timeline::before {
        left: -2.35rem;
    }

    .footer-content {
        flex-direction: column;
        gap: 1.5rem;
        text-align: center;
    }
}