:root {
    --text-primary: #1a1a1a;
    --text-secondary: #4a4a4a;
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --border-color: #e0e0e0;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
}

@media (prefers-color-scheme: dark) {
    :root {
        --text-primary: #e5e5e5;
        --text-secondary: #b0b0b0;
        --bg-primary: #121212;
        --bg-secondary: #1e1e1e;
        --border-color: #333333;
        --accent: #3b82f6;
        --accent-hover: #60a5fa;
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    padding: 2rem 1rem;
    max-width: 900px;
    margin: 0 auto;
}

@media (min-width: 768px) {
    body {
        padding: 3rem 2rem;
    }
}

nav {
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1.5rem;
}

.site-title {
    text-decoration: none;
    transition: color 0.2s;
}

.site-title h2 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
    line-height: 1.2;
}

.site-title p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin: 0.25rem 0 0 0;
    line-height: 1.2;
}

.site-title:hover h2 {
    color: var(--accent);
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    list-style: none;
    flex-wrap: wrap;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9375rem;
    transition: color 0.2s;
}

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

.nav-links a.active {
    color: var(--text-primary);
    font-weight: 500;
}

header {
    margin-bottom: 3rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
}

h1 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

h2 {
    font-size: 1.5rem;
    font-weight: 500;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

h3 {
    font-size: 1.25rem;
    font-weight: 500;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.summary {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.7;
    margin-bottom: 1rem;
}

.contact-info {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    margin-top: 0.75rem;
    line-height: 1.8;
}

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

.contact-info a:hover {
    color: var(--accent);
    text-decoration: underline;
}

.note {
    background-color: var(--bg-secondary);
    border-left: 3px solid var(--accent);
    padding: 1rem 1.25rem;
    margin: 2rem 0;
    font-size: 0.9375rem;
    color: var(--text-secondary);
    border-radius: 0 4px 4px 0;
}

section {
    margin-bottom: 3.5rem;
}

/* Home page styles */
.cta-section {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 2rem;
    margin: 2.5rem 0;
    text-align: center;
}

.cta-button {
    display: inline-block;
    background-color: var(--accent);
    color: white;
    padding: 0.75rem 2rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    margin-top: 1rem;
    transition: background-color 0.2s;
}

.cta-button:hover {
    background-color: var(--accent-hover);
}

.quick-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 2rem;
}

.quick-link-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 1.5rem;
    text-align: center;
}

.quick-link-card a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 500;
}

.quick-link-card a:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

/* Engineering page styles */
.case-studies-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    margin-top: 1.5rem;
}

@media (max-width: 1024px) {
    .case-studies-grid {
        grid-template-columns: 1fr;
    }
}

.case-study {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 1.25rem;
    display: flex;
    flex-direction: column;
    height: 100%;
    transition: transform 0.2s, box-shadow 0.2s;
}

.case-study:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.case-study h3 {
    margin-top: 0;
    margin-bottom: 0.75rem;
    font-size: 1.125rem;
    line-height: 1.4;
}

.case-study-summary {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 0.75rem;
    flex-grow: 1;
}

.case-study-tech {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-style: italic;
}

.case-study-link {
    display: inline-block;
    color: var(--accent);
    text-decoration: none;
    font-size: 0.9375rem;
    font-weight: 500;
    margin-top: auto;
}

.case-study-link:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

.case-study-link::after {
    content: " →";
}

.case-study-subsection {
    margin-bottom: 1.5rem;
}

.case-study-subsection h4 {
    font-size: 0.9375rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.case-study-subsection ul {
    list-style: none;
    padding-left: 0;
}

.case-study-subsection li {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    padding-left: 1.25rem;
    position: relative;
    line-height: 1.6;
}

.case-study-subsection li:before {
    content: "•";
    position: absolute;
    left: 0.5rem;
    color: var(--accent);
}

.skills-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    list-style: none;
    padding: 0;
}

.skills-list li {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    font-size: 0.9375rem;
    color: var(--text-primary);
}

/* Portfolio page styles */
.project-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 2rem;
    margin-bottom: 2rem;
}

.project-card h3 {
    margin-top: 0;
    margin-bottom: 0.5rem;
}

.project-link {
    display: inline-block;
    color: var(--accent);
    text-decoration: none;
    font-size: 1rem;
    margin-bottom: 1rem;
    font-weight: 500;
}

.project-link:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

.project-link::after {
    content: " →";
}

.project-description {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.7;
    margin-bottom: 1rem;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1rem;
}

.tech-tag {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.8125rem;
    color: var(--text-secondary);
}

/* Project detail pages */
.back-link {
    display: inline-block;
    color: var(--accent);
    text-decoration: none;
    font-size: 0.9375rem;
    margin-bottom: 1.5rem;
}

.back-link:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

.tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1rem;
}

.tech-tags .tech-tag {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    font-size: 0.875rem;
    color: var(--text-primary);
}

/* Footer */
footer {
    margin-top: 4rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

footer nav {
    display: flex;
    justify-content: center;
    align-items: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.5rem;
    flex-wrap: wrap;
    list-style: none;
    margin: 0;
    padding: 0;
}

.footer-links li {
    margin: 0;
    padding: 0;
}

.footer-links a {
    color: var(--accent);
    text-decoration: none;
    font-size: 0.9375rem;
    transition: color 0.2s;
}

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

/* Responsive */
@media (max-width: 767px) {
    h1 {
        font-size: 1.75rem;
    }

    h2 {
        font-size: 1.25rem;
    }

    nav {
        flex-direction: column;
        align-items: flex-start;
    }

    .site-title {
        margin-bottom: 0.5rem;
    }

    .site-title h2 {
        font-size: 1rem;
    }

    .site-title p {
        font-size: 0.8125rem;
    }

    .case-study {
        padding: 1.25rem;
    }

    .case-studies-grid {
        gap: 1rem;
    }

    .project-card {
        padding: 1.5rem;
    }
}

@media print {
    body {
        padding: 1rem;
        max-width: 100%;
    }

    .case-study {
        page-break-inside: avoid;
        margin-bottom: 1rem;
    }

    .footer-links a {
        color: var(--text-primary);
    }

    .note {
        border-left-width: 2px;
    }
}