/* ===================================
   GLOBAL STYLES & RESET
   =================================== */

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

:root {
    /* Professional Light Color Palette */
    --primary-color: #1a202c;        /* Dark slate for headings */
    --secondary-color: #2d3748;      /* Medium slate for body text */
    --accent-color: #3b82f6;         /* Professional blue */
    --accent-hover: #2563eb;         /* Darker blue on hover */
    --text-primary: #1a202c;         /* Primary text */
    --text-secondary: #4a5568;       /* Secondary text */
    --text-light: #718096;           /* Light text */
    --text-dark: #1a202c;            /* Darkest text */
    --background: #ffffff;           /* White background */
    --background-light: #f7fafc;     /* Light gray background */
    --background-alt: #edf2f7;       /* Alternate section background */
    --white: #ffffff;
    --light-gray: #f8f9fa;
    --border-color: #e2e8f0;         /* Light borders */

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
    --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    /* Spacing - Improved scale */
    --spacing-xs: 0.5rem;    /* 8px */
    --spacing-sm: 1rem;      /* 16px */
    --spacing-md: 1.5rem;    /* 24px */
    --spacing-lg: 2.5rem;    /* 40px */
    --spacing-xl: 4rem;      /* 64px */
    --spacing-2xl: 6rem;     /* 96px */

    /* Transitions */
    --transition-fast: 0.15s ease-out;
    --transition-normal: 0.25s ease-out;
    --transition-slow: 0.4s ease-out;

    /* Shadows - Softer */
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Border Radius */
    --radius-sm: 0.25rem;    /* 4px */
    --radius-md: 0.5rem;     /* 8px */
    --radius-lg: 0.75rem;    /* 12px */
    --radius-xl: 1rem;       /* 16px */
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    font-size: 1.0625rem;        /* 17px - better readability */
    line-height: 1.75;           /* Improved line height for reading */
    color: var(--text-secondary);
    background-color: var(--background);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

section {
    padding: var(--spacing-2xl) 0;  /* More breathing room */
}

/* Section spacing improvements */
.section {
    position: relative;
    padding: var(--spacing-2xl) 0;
}

.section + .section {
    margin-top: 0;
}

.section--alt {
    background-color: var(--background-alt);
    padding: var(--spacing-2xl) 0;
}

.section--default {
    background-color: var(--background);
    padding: var(--spacing-2xl) 0;
}

/* Max-width for readable text blocks */
.section-content {
    max-width: 65ch;  /* Optimal reading width */
    margin-left: auto;
    margin-right: auto;
}

.section-content--wide {
    max-width: 100%;  /* For grids/cards */
}

/* ===================================
   TYPOGRAPHY
   =================================== */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    color: var(--text-primary);
    line-height: 1.3;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    font-weight: 700;
    letter-spacing: -0.02em;  /* Tighter tracking for headings */
}

h1:first-child, h2:first-child, h3:first-child {
    margin-top: 0;
}

h1 {
    font-size: clamp(2.25rem, 5vw, 3.5rem);
    font-weight: 800;
    margin-bottom: var(--spacing-lg);
}

h2 {
    font-size: clamp(1.875rem, 4vw, 2.5rem);
    font-weight: 700;
    margin-top: var(--spacing-xl);
}

h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 600;
}

h4 {
    font-size: 1.375rem;
    font-weight: 600;
    color: var(--text-secondary);
}

p {
    margin-bottom: var(--spacing-md);
    max-width: 65ch;
}

p:last-child {
    margin-bottom: 0;
}

.lead {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

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

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

/* Loading/Transition States */
.fade-in {
    animation: fadeIn var(--transition-slow) ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Smooth scroll offset for fixed header */
html {
    scroll-padding-top: 80px;  /* Account for fixed nav height */
}

/* ===================================
   NAVIGATION
   =================================== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(10, 25, 47, 0.95);
    backdrop-filter: blur(10px);
    padding: var(--spacing-sm) 0;
    z-index: 1000;
    transition: all var(--transition-normal);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

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

.nav-brand a {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    transition: color var(--transition-fast);
}

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

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-md);
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    padding: 0.5rem 1rem;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background-color: var(--accent-color);
    transition: width var(--transition-normal);
}

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

.nav-link:hover::after,
.nav-link.active::after {
    width: 80%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    margin: 3px 0;
    transition: all var(--transition-fast);
}

/* ===================================
   BUTTONS
   =================================== */

.btn {
    display: inline-block;
    padding: 1rem 2rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    text-align: center;
    transition: all var(--transition-normal);
    cursor: pointer;
    border: 2px solid transparent;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: transparent;
    color: var(--accent-color);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(100, 255, 218, 0.2);
}

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

.btn-secondary:hover {
    background-color: rgba(100, 255, 218, 0.1);
    transform: translateY(-2px);
}

/* ===================================
   HERO SECTION
   =================================== */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding-top: 80px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
}

.hero-content {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
    animation: fadeInUp 1s ease;
}

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

.hero-subtitle {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    color: var(--accent-color);
    margin-bottom: var(--spacing-md);
    font-weight: 500;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

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

.hero-scroll {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
    animation: bounce 2s infinite;
}

/* ===================================
   SECTION HEADERS
   =================================== */

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.section-title {
    color: var(--text-primary);
    position: relative;
    display: inline-block;
}

.section-divider {
    width: 80px;
    height: 4px;
    background-color: var(--accent-color);
    margin: var(--spacing-sm) auto;
    border-radius: 2px;
}

/* ===================================
   ABOUT SECTION
   =================================== */

.about {
    background-color: var(--secondary-color);
}

.about-content {
    display: grid;
    gap: var(--spacing-lg);
}

.about-text p {
    font-size: 1.125rem;
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.stat-item {
    text-align: center;
    padding: var(--spacing-md);
    background-color: var(--primary-color);
    border-radius: var(--radius-lg);
    transition: transform var(--transition-normal);
}

.stat-item:hover {
    transform: translateY(-5px);
}

.stat-number {
    display: block;
    font-size: 3rem;
    font-weight: 700;
    color: var(--accent-color);
    font-family: var(--font-heading);
}

.stat-label {
    display: block;
    color: var(--text-secondary);
    font-size: 1rem;
    margin-top: var(--spacing-xs);
}

/* ===================================
   EXPERIENCE SECTION (TIMELINE)
   =================================== */

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

.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background-color: var(--accent-color);
}

.timeline-item {
    position: relative;
    padding-left: 3rem;
    margin-bottom: var(--spacing-lg);
}

.timeline-marker {
    position: absolute;
    left: -6px;
    top: 0;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background-color: var(--accent-color);
    border: 3px solid var(--primary-color);
    z-index: 1;
}

.timeline-content {
    background-color: var(--secondary-color);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.timeline-content:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow-lg);
}

.timeline-date {
    display: inline-block;
    color: var(--accent-color);
    font-weight: 600;
    font-size: 0.875rem;
    margin-bottom: var(--spacing-xs);
}

.timeline-content h3 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.timeline-location {
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-style: italic;
    margin-bottom: var(--spacing-sm);
}

.timeline-content p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ===================================
   VENTURES SECTION
   =================================== */

.ventures {
    background-color: var(--secondary-color);
}

.ventures-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.venture-card {
    background-color: var(--primary-color);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
    border: 1px solid rgba(100, 255, 218, 0.1);
}

.venture-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(100, 255, 218, 0.1);
    border-color: var(--accent-color);
}

.venture-card h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.venture-year {
    display: block;
    color: var(--accent-color);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.venture-card p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

.venture-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.tag {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background-color: rgba(100, 255, 218, 0.1);
    color: var(--accent-color);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 600;
}

/* ===================================
   EDUCATION SECTION
   =================================== */

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

.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.education-card {
    background-color: var(--secondary-color);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    text-align: center;
    transition: transform var(--transition-normal);
}

.education-card:hover {
    transform: translateY(-5px);
}

.education-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.education-card h3 {
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.education-institution {
    color: var(--accent-color);
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.education-year {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-sm);
}

.education-note {
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-style: italic;
}

/* ===================================
   PUBLICATIONS SECTION
   =================================== */

.publications {
    background-color: var(--secondary-color);
}

.publications-content {
    max-width: 900px;
    margin: 0 auto;
}

.pub-category {
    margin-bottom: var(--spacing-lg);
}

.category-title {
    color: var(--accent-color);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-xs);
    border-bottom: 2px solid var(--accent-color);
}

.pub-list {
    display: grid;
    gap: var(--spacing-md);
}

.pub-item {
    background-color: var(--primary-color);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--accent-color);
    transition: transform var(--transition-fast);
}

.pub-item:hover {
    transform: translateX(5px);
}

.pub-item h4 {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.pub-year,
.pub-details {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ===================================
   CONTACT SECTION
   =================================== */

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

.contact-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    max-width: 1000px;
    margin: 0 auto;
}

.contact-info h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.contact-info p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

.contact-details {
    display: grid;
    gap: var(--spacing-md);
}

.contact-item {
    display: flex;
    gap: var(--spacing-sm);
    align-items: start;
}

.contact-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.contact-item h4 {
    font-size: 1rem;
    color: var(--accent-color);
    margin-bottom: 0.25rem;
}

.contact-item p {
    color: var(--text-secondary);
    margin: 0;
}

.contact-item a {
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

.contact-item a:hover {
    color: var(--accent-color);
}

/* Contact Form */
.contact-form-container {
    background-color: var(--secondary-color);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
}

.contact-form {
    display: grid;
    gap: var(--spacing-sm);
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    padding: 0.75rem;
    background-color: var(--primary-color);
    border: 1px solid rgba(100, 255, 218, 0.2);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 1rem;
    transition: border-color var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-color);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.contact-form .btn {
    margin-top: var(--spacing-sm);
}

/* ===================================
   FOOTER
   =================================== */

.footer {
    background-color: var(--secondary-color);
    padding: var(--spacing-md) 0;
    text-align: center;
    border-top: 1px solid rgba(100, 255, 218, 0.1);
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.footer p {
    color: var(--text-secondary);
    margin: 0;
}

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

.footer-links a {
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

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

/* ===================================
   ANIMATIONS
   =================================== */

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

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

/* ===================================
   UTILITY CLASSES
   =================================== */

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

.mb-1 {
    margin-bottom: var(--spacing-sm);
}

.mb-2 {
    margin-bottom: var(--spacing-md);
}

.mb-3 {
    margin-bottom: var(--spacing-lg);
}

.mt-1 {
    margin-top: var(--spacing-sm);
}

.mt-2 {
    margin-top: var(--spacing-md);
}

.mt-3 {
    margin-top: var(--spacing-lg);
}

/* ===================================
   GRID LAYOUTS
   =================================== */

.projects-grid,
.roles-grid,
.experience-grid,
.videos-grid,
.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

@media (max-width: 768px) {
    .projects-grid,
    .roles-grid,
    .experience-grid,
    .videos-grid,
    .portfolio-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
}

/* Section variants */
.section--alt {
    background-color: var(--background-light);
}

.section--dark {
    background-color: var(--secondary-color);
    color: var(--text-primary);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.section-title {
    margin-bottom: var(--spacing-sm);
}

.section-divider {
    width: 60px;
    height: 3px;
    background-color: var(--accent-color);
    margin: var(--spacing-sm) auto;
}