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

:root {
    --color-primary: #2c3e50;
    --color-secondary: #3498db;
    --color-text: #333;
    --color-text-light: #666;
    --color-background: #fff;
    --color-border: #e0e0e0;
    --font-main: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    --max-width: 1200px;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 2rem;
}

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

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

/* Header */
.header {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--color-primary);
}

.header-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.headshot {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    object-position: center 20%;
    border: 3px solid var(--color-primary);
    flex-shrink: 0;
}

.header-text {
    flex: 1;
}

.header h1 {
    font-size: 2.5rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.header .title {
    font-size: 1.25rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
}

.contact-info {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    font-size: 0.9rem;
}

.contact-info a {
    color: var(--color-secondary);
    text-decoration: none;
}

.contact-info a:hover {
    text-decoration: underline;
}

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

.social-links a {
    color: var(--color-primary);
    transition: color 0.3s;
}

.social-links a:hover {
    color: var(--color-secondary);
}

/* Tabs Navigation */
.tabs {
    display: flex;
    flex-wrap: nowrap;
    gap: 0;
    margin-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--color-border);
}

.tab-button {
    background-color: transparent;
    color: var(--color-text);
    border: none;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.9rem;
    font-family: var(--font-main);
    cursor: pointer;
    border-bottom: 3px solid transparent;
    transition: all 0.3s ease;
    margin-bottom: -2px;
    white-space: nowrap;
    flex-shrink: 0;
}

.tab-button:hover {
    color: var(--color-secondary);
    background-color: rgba(52, 152, 219, 0.05);
}

.tab-button.active {
    color: var(--color-secondary);
    border-bottom-color: var(--color-secondary);
    font-weight: 600;
}

/* Tab Content */
.tab-content {
    display: none;
    animation: fadeIn 0.3s ease-in;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Sections */
.section {
    margin-bottom: var(--spacing-lg);
}

.section h2 {
    font-size: 1.5rem;
    color: var(--color-primary);
    border-bottom: 1px solid var(--color-border);
    padding-bottom: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

/* Jobs */
.job {
    margin-bottom: var(--spacing-lg);
}

.job:last-child {
    margin-bottom: 0;
}

.job-header {
    margin-bottom: var(--spacing-sm);
}

.job-header h3 {
    font-size: 1.1rem;
    color: var(--color-text);
}

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

.job-header .date {
    display: block;
    font-size: 0.9rem;
    color: var(--color-text-light);
}

.job ul {
    margin-left: var(--spacing-lg);
}

.job li {
    margin-bottom: var(--spacing-sm);
}

/* Education */
.education {
    margin-bottom: var(--spacing-md);
}

.education h3 {
    font-size: 1.1rem;
    margin-bottom: 0.25rem;
}

.education .school {
    font-weight: 600;
    color: var(--color-secondary);
}

.education .date {
    display: block;
    font-size: 0.9rem;
    color: var(--color-text-light);
}

/* Key Strengths Grid */
.strengths-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.strength-column h3 {
    font-size: 1rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.strength-column ul {
    list-style: none;
    font-size: 0.9rem;
}

.strength-column li {
    margin-bottom: 0.25rem;
}

/* Skills */
.skills {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.skill {
    background-color: #f0f0f0;
    color: var(--color-text);
    border: 1px solid var(--color-border);
    padding: 0.25rem 0.75rem;
    border-radius: 3px;
    font-size: 0.9rem;
}

/* Tech Categories */
.tech-category {
    margin-bottom: var(--spacing-lg);
}

.tech-category h3 {
    font-size: 1.1rem;
    color: var(--color-secondary);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.tech-description {
    margin-top: var(--spacing-sm);
    font-size: 0.95rem;
    color: var(--color-text-light);
    line-height: 1.5;
}

/* Engagements */
.engagements {
    list-style: none;
}

.engagements li {
    margin-bottom: var(--spacing-sm);
    padding-left: var(--spacing-md);
    position: relative;
}

.engagements li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 0.6em;
    width: 6px;
    height: 6px;
    background-color: var(--color-secondary);
    border-radius: 50%;
}

/* Two Column Layout */
.two-column {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
}

.two-column h3 {
    font-size: 1rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.two-column p {
    margin-bottom: 0.25rem;
}

.patent-number,
.school {
    font-size: 0.9rem;
    color: var(--color-text-light);
}

/* Footer */
footer {
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-border);
    text-align: center;
    font-size: 0.85rem;
    color: var(--color-text-light);
}

/* Print Styles */
@media print {
    body {
        font-size: 12pt;
    }

    .container {
        max-width: 100%;
        padding: 0;
    }

    .header {
        border-bottom-width: 1px;
    }

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

    .skill {
        background-color: transparent;
        color: var(--color-text);
        border: 1px solid var(--color-border);
    }
}

/* Return to Top Button */
.return-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--color-primary);
    color: white;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
    z-index: 1000;
}

.return-to-top.visible {
    opacity: 0.75;
    visibility: visible;
}

.return-to-top:hover {
    opacity: 1;
}

/* Responsive */
@media (max-width: 600px) {
    .container {
        padding: var(--spacing-md);
    }

    .header h1 {
        font-size: 2rem;
    }

    .header-content {
        flex-direction: column;
        text-align: center;
    }

    .contact-info {
        justify-content: center;
        flex-direction: column;
        gap: var(--spacing-sm);
    }

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

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

    .two-column {
        grid-template-columns: 1fr;
    }

    .tabs {
        flex-direction: column;
        border-bottom: none;
    }

    .tab-button {
        width: 100%;
        text-align: left;
        border-bottom: 1px solid var(--color-border);
        border-left: 3px solid transparent;
        margin-bottom: 0;
        padding: var(--spacing-md);
    }

    .tab-button.active {
        border-bottom-color: var(--color-border);
        border-left-color: var(--color-secondary);
    }
}