/* ===================================
   CSS Variables
   =================================== */
:root {
    /* Colors */
    --color-primary: #0D7377;
    --color-primary-dark: #0a5c5f;
    --color-accent: #E85D75;
    --color-text-dark: #2D3142;
    --color-text-medium: #4f5568;
    --color-text-light: #6b7280;
    --color-bg-light: #F8F9FA;
    --color-bg-secondary: #E8EEF2;
    --color-white: #FFFFFF;
    --color-border: #e5e7eb;

    /* Typography */
    --font-heading: 'Merriweather', serif;
    --font-body: 'Inter', sans-serif;

    /* Spacing */
    --section-padding: 5rem 0;
    --container-max-width: 1200px;
    --container-padding: 0 2rem;

    /* Transitions */
    --transition: all 0.3s ease;
}

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

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

body {
    font-family: var(--font-body);
    color: var(--color-text-dark);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ===================================
   Typography
   =================================== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 1rem;
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.5rem;
}

p {
    margin-bottom: 1rem;
}

.lead {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: 1.5rem;
}

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

.section {
    padding: var(--section-padding);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--color-text-dark);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--color-accent);
    margin: 1rem auto 0;
    border-radius: 2px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    text-decoration: none;
    border-radius: 4px;
    font-weight: 600;
    transition: var(--transition);
    font-size: 1rem;
    cursor: pointer;
    border: 2px solid transparent;
}

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

.btn-primary:hover {
    background: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(13, 115, 119, 0.3);
}

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

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

/* ===================================
   Navigation
   =================================== */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--color-white);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    z-index: 1000;
    transition: var(--transition);
}

.navbar.scrolled {
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

.nav-container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-brand {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary);
    text-decoration: none;
    letter-spacing: 1px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--color-text-dark);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-accent);
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--color-primary);
}

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

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

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: var(--color-text-dark);
    margin: 3px 0;
    transition: var(--transition);
    border-radius: 2px;
}

/* ===================================
   Hero Section
   =================================== */
.hero {
    padding: 150px 0 100px;
    background: linear-gradient(135deg, var(--color-bg-light) 0%, var(--color-bg-secondary) 100%);
    margin-top: 70px;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 3.5rem;
    margin-bottom: 0.5rem;
    color: var(--color-text-dark);
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--color-primary);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.hero-tagline {
    font-family: var(--font-heading);
    font-size: 1.125rem;
    font-style: italic;
    color: var(--color-text-medium);
    margin-bottom: 1.5rem;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--color-text-medium);
    margin-bottom: 2rem;
    line-height: 1.8;
}

/* ===================================
   About Section
   =================================== */
.about-section {
    background: var(--color-white);
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 3rem;
    align-items: start;
}

.about-image-wrapper {
    position: sticky;
    top: 100px;
}

.about-image {
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
    transition: var(--transition);
}

.about-image:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.15);
}

.about-text p {
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--color-text-medium);
    margin-bottom: 1.5rem;
}

/* ===================================
   Experience Section
   =================================== */
.experience-section {
    background: var(--color-bg-light);
}

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

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: var(--color-primary);
}

.timeline-item {
    position: relative;
    padding-left: 50px;
    margin-bottom: 3rem;
}

.timeline-marker {
    position: absolute;
    left: -8px;
    top: 0;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--color-accent);
    border: 3px solid var(--color-white);
    box-shadow: 0 0 0 3px var(--color-primary);
}

.timeline-content {
    background: var(--color-white);
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
}

.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.5rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.timeline-header h3 {
    color: var(--color-text-dark);
    font-size: 1.25rem;
    margin-bottom: 0;
}

.timeline-date {
    color: var(--color-primary);
    font-weight: 600;
    font-size: 0.9375rem;
}

.timeline-company {
    color: var(--color-text-medium);
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.timeline-content p:last-child {
    margin-bottom: 0;
    color: var(--color-text-medium);
    line-height: 1.7;
}

/* ===================================
   Expertise Section
   =================================== */
.expertise-section {
    background: var(--color-white);
}

.expertise-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.expertise-category {
    background: var(--color-bg-light);
    padding: 2rem;
    border-radius: 8px;
    transition: var(--transition);
}

.expertise-category:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.expertise-category h3 {
    color: var(--color-primary);
    font-size: 1.25rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.expertise-category h3 i {
    font-size: 1.5rem;
    color: var(--color-accent);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.tag {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: var(--color-white);
    color: var(--color-text-dark);
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
    transition: var(--transition);
    border: 1px solid var(--color-border);
}

.tag:hover {
    background: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

/* ===================================
   Education Section
   =================================== */
.education-section {
    background: var(--color-bg-secondary);
}

.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.education-card {
    background: var(--color-white);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
    transition: var(--transition);
}

.education-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

.education-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.education-icon i {
    font-size: 1.75rem;
    color: var(--color-white);
}

.education-card h3 {
    color: var(--color-text-dark);
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.education-school {
    color: var(--color-primary);
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.education-focus {
    color: var(--color-text-medium);
    font-size: 0.9375rem;
    line-height: 1.6;
}

.publications-cta {
    text-align: center;
    max-width: 700px;
    margin: 3rem auto 0;
    padding: 2rem;
    background: var(--color-white);
    border-radius: 8px;
}

.publications-cta p {
    font-size: 1.125rem;
    color: var(--color-text-medium);
    margin-bottom: 1.5rem;
}

/* ===================================
   Publications & Projects Section
   =================================== */
.publications-projects-section {
    background: var(--color-bg-light);
}

.publications-projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.pub-project-card {
    background: var(--color-white);
    padding: 2.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
    transition: var(--transition);
    border: 2px solid transparent;
}

.pub-project-card:hover {
    border-color: var(--color-primary);
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

.pub-project-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.pub-project-icon i {
    font-size: 1.75rem;
    color: var(--color-white);
}

.pub-project-card h3 {
    color: var(--color-text-dark);
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.pub-project-card p {
    color: var(--color-text-medium);
    line-height: 1.7;
    margin-bottom: 1rem;
}

.featured-item {
    font-size: 0.9375rem;
    color: var(--color-primary);
    font-style: italic;
    margin-bottom: 1.5rem;
}

.pub-project-card .btn {
    margin-top: 0.5rem;
}

/* ===================================
   Writing Section
   =================================== */
.writing-section {
    background: var(--color-white);
}

.writing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.writing-card {
    background: var(--color-bg-light);
    padding: 2rem;
    border-radius: 8px;
    transition: var(--transition);
    border: 2px solid transparent;
}

.writing-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.writing-icon {
    width: 50px;
    height: 50px;
    background: var(--color-accent);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.writing-icon i {
    font-size: 1.5rem;
    color: var(--color-white);
}

.writing-card h3 {
    color: var(--color-text-dark);
    font-size: 1.375rem;
    margin-bottom: 1rem;
}

.writing-card p {
    color: var(--color-text-medium);
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

.writing-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--color-primary);
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
}

.writing-link:hover {
    color: var(--color-accent);
    gap: 0.75rem;
}

.writing-link i {
    font-size: 0.875rem;
}

/* ===================================
   Contact Section
   =================================== */
.contact-section {
    background: var(--color-bg-light);
}

.contact-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.contact-intro {
    font-size: 1.125rem;
    color: var(--color-text-medium);
    margin-bottom: 2rem;
}

.contact-options {
    margin-bottom: 2.5rem;
}

.contact-email {
    display: inline-flex;
    align-items: center;
    gap: 1rem;
    padding: 1.25rem 2.5rem;
    background: var(--color-primary);
    color: var(--color-white);
    text-decoration: none;
    border-radius: 8px;
    font-size: 1.125rem;
    font-weight: 600;
    transition: var(--transition);
}

.contact-email:hover {
    background: var(--color-primary-dark);
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(13, 115, 119, 0.3);
}

.contact-email i {
    font-size: 1.5rem;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 2.5rem;
}

.social-links a {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-white);
    color: var(--color-primary);
    border-radius: 50%;
    text-decoration: none;
    transition: var(--transition);
    font-size: 1.25rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.social-links a:hover {
    background: var(--color-primary);
    color: var(--color-white);
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(13, 115, 119, 0.3);
}

.business-link {
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
}

.business-link p {
    color: var(--color-text-medium);
    font-size: 1rem;
}

.business-link a {
    color: var(--color-primary);
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
}

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

/* ===================================
   Footer
   =================================== */
.footer {
    background: var(--color-text-dark);
    color: var(--color-white);
    padding: 2rem 0;
    text-align: center;
}

.footer p {
    margin: 0;
    opacity: 0.9;
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 768px) {
    :root {
        --section-padding: 3rem 0;
    }

    /* Navigation */
    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background: var(--color-white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 2rem 0;
        gap: 1rem;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle.active span:nth-child(1) {
        transform: translateY(9px) rotate(45deg);
    }

    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active span:nth-child(3) {
        transform: translateY(-9px) rotate(-45deg);
    }

    /* Hero */
    .hero {
        padding: 100px 0 60px;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.25rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    /* Typography */
    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.75rem;
    }

    .section-title {
        font-size: 2rem;
    }

    /* About */
    .about-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .about-image-wrapper {
        position: static;
        max-width: 280px;
        margin: 0 auto;
    }

    /* Timeline */
    .timeline::before {
        left: 8px;
    }

    .timeline-item {
        padding-left: 40px;
    }

    .timeline-header {
        flex-direction: column;
        align-items: flex-start;
    }

    /* Grids */
    .expertise-grid,
    .education-grid,
    .writing-grid {
        grid-template-columns: 1fr;
    }

    /* Contact */
    .contact-email {
        padding: 1rem 1.5rem;
        font-size: 1rem;
    }

    .social-links {
        gap: 1rem;
    }

    .social-links a {
        width: 45px;
        height: 45px;
        font-size: 1.125rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    .hero-title {
        font-size: 2rem;
    }

    .btn {
        padding: 0.75rem 1.5rem;
        font-size: 0.9375rem;
    }
}

/* ===================================
   Print Styles
   =================================== */
@media print {
    .navbar,
    .nav-toggle,
    .footer {
        display: none;
    }

    .hero {
        margin-top: 0;
        padding: 2rem 0;
    }

    .section {
        page-break-inside: avoid;
        padding: 1rem 0;
    }
}