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

:root {
    --bg-color: #ffffff;
    --text-color: #111111;
    --text-secondary: #666666;
    --accent: #e74c3c;
    --border-color: #e5e5e5;
    --section-bg: #fafafa;
    --card-bg: #ffffff;
    --card-shadow: 0 2px 8px rgba(0,0,0,0.08);
    --max-width: 1100px;
    --transition: all 0.15s ease;
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 40px;
    --spacing-xl: 60px;
}

[data-theme="dark"] {
    --bg-color: #0a0a0a;
    --text-color: #f0f0f0;
    --text-secondary: #a0a0a0;
    --accent: #e74c3c;
    --border-color: #2a2a2a;
    --section-bg: #000000; /* Pitch black for dark headers */
    --card-bg: #1a1a1a;
    --card-shadow: 0 2px 8px rgba(0,0,0,0.4);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    font-size: 16px;
    transition: var(--transition);
}

.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--accent);
    color: white;
    padding: 8px;
    text-decoration: none;
    z-index: 100;
}

.skip-link:focus {
    top: 0;
}

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

nav {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--bg-color);
    z-index: 100;
    padding: var(--spacing-md) 0;
    opacity: 0;
    transform: translateY(-100%);
    transition: opacity 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

nav.visible {
    opacity: 1;
    transform: translateY(0);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    backdrop-filter: blur(8px);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center; /* Ensures center-line alignment */
    gap: var(--spacing-sm);
}

nav ul {
    list-style: none;
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
    margin: 0;
}

nav a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.15s ease;
    position: relative;
    white-space: nowrap;
}

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

nav a:focus {
    outline: 2px solid var(--accent);
    outline-offset: 4px;
}

/* Mobile nowrap hack preserved for desktop sim */
@media (max-width: 768px) {
    nav ul li:nth-child(4) a {
        font-size: 0;
    }
    nav ul li:nth-child(4) a::before {
        content: "Log";
        font-size: 0.875rem;
    }
}

/* Hamburger for mobile */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
    padding: 4px;
    background: none;
    border: none;
}

.hamburger span {
    width: 24px;
    height: 2px;
    background: var(--text-color);
    transition: var(--transition);
    border-radius: 1px;
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

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

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

.hamburger:focus {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.mobile-menu {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: var(--bg-color);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-lg);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    z-index: 99;
    padding-top: var(--spacing-xl);
}

.mobile-menu.active {
    opacity: 1;
    visibility: visible;
}

.mobile-menu-header {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.close-menu {
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
    color: var(--text-color);
    font-size: 1.5rem;
    transition: color 0.15s ease;
}

.close-menu:hover {
    color: var(--accent);
}

.close-menu svg {
    width: 24px;
    height: 24px;
    fill: currentColor;
}

.mobile-menu a {
    font-size: 1.25rem;
    font-weight: 600;
}

.theme-toggle {
    position: relative;
    width: 56px;
    height: 28px;
    background: var(--border-color);
    border-radius: 30px;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid var(--border-color);
    flex-shrink: 0;
    align-self: center;
    transform: translateY(-9px); /* Precise upward nudge for center-line alignment with nav text */
}

.theme-toggle.active {
    background: var(--accent);
    border-color: var(--accent);
}

.toggle-slider {
    position: absolute;
    top: 2px;
    left: 2px;
    width: 20px;
    height: 20px;
    background: var(--bg-color);
    border-radius: 50%;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle.active .toggle-slider {
    transform: translateX(28px);
}

.toggle-icon {
    width: 12px;
    height: 12px;
    fill: var(--text-color);
    transition: fill 0.2s ease;
}

header {
    text-align: center;
    padding: var(--spacing-xl) var(--spacing-md);
    background: var(--section-bg);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

header h1 {
    font-size: clamp(2.5rem, 8vw, 5rem);
    font-weight: 900;
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-sm);
    line-height: 1.2; /* Tightens vertical space */
    transition: var(--transition);
}

.subtitle {
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    color: var(--text-secondary);
    font-weight: 400;
    margin-bottom: var(--spacing-lg);
    transition: var(--transition);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.5;
}

/* Exact case study header overrides - tightened verticals */
header[style*="Spaceship"] h1 {
    font-size: clamp(2rem, 6vw, 3rem) !important;
    line-height: 1.2 !important; /* Matches tightened h1 */
    margin-bottom: var(--spacing-xs) !important; /* Reduces gap to p */
}

header[style*="Spaceship"] p {
    color: var(--text-secondary) !important;
    font-size: clamp(1rem, 2vw, 1.125rem) !important;
    font-style: italic !important;
    margin-top: 0 !important; /* No extra top gap */
}

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

.cta {
    display: inline-block;
    background: var(--accent);
    color: #ffffff;
    padding: 14px 28px;
    text-decoration: none;
    font-weight: 600;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    border-radius: 4px;
}

.cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(231, 76, 60, 0.3);
}

.cta:focus {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

section {
    padding: var(--spacing-xl) 0;
    transition: var(--transition);
}

main {
    padding-top: var(--spacing-lg);
}

/* Exact case study main styles - preserved verbatim */
main {
    max-width: 800px;
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-md);
}

h2 {
    font-size: clamp(1.5rem, 3vw, 1.75rem);
    font-weight: 900;
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.02em;
    color: var(--text-color);
}

h2:first-child {
    margin-top: 0;
}

h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    color: var(--text-color);
}

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

ul {
    padding-left: 20px;
    margin-bottom: var(--spacing-md);
}

li {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: var(--spacing-xl) 0;
}

img {
    display: block;
    max-width: 100%;
    border-radius: 6px;
    margin: var(--spacing-md) auto;
    box-shadow: var(--card-shadow);
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: var(--spacing-lg);
}

th, td {
    border: 1px solid var(--border-color);
    padding: 12px;
    text-align: left;
}

th {
    background: var(--section-bg);
    font-weight: 600;
    color: var(--text-color);
}

td {
    color: var(--text-secondary);
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: opacity 0.15s ease;
}

a:hover {
    opacity: 0.8;
}

a:focus {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.back-link {
    display: inline-block;
    margin-top: var(--spacing-xl);
    color: var(--accent);
    font-weight: 600;
}

.projects-grid, .articles-grid {
    display: grid;
    gap: var(--spacing-lg);
}

.project, .article-card {
    padding: var(--spacing-lg) 0;
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
}

.project:hover, .article-card:hover {
    padding-left: var(--spacing-sm);
}

.project-tech, .article-tags {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    margin-bottom: var(--spacing-md);
}

.tech-tag, .article-tag {
    font-size: 0.875rem;
    color: var(--text-secondary);
    padding: 4px 12px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    border-radius: 4px;
}

.article-tag {
    background: var(--accent);
    color: #ffffff;
    border: none;
    font-size: 0.75rem;
    padding: 4px 8px;
    border-radius: 2px;
}

.project-link {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: gap 0.15s ease, color 0.15s ease;
}

.project-link:hover {
    gap: 16px;
    color: var(--accent);
}

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

.about-text {
    max-width: 700px;
    margin: 0 auto;
    font-size: 1.125rem;
    text-align: center;
    color: var(--text-secondary);
    transition: var(--transition);
    line-height: 1.7;
}

.about-text strong {
    color: var(--text-color);
    font-weight: 600;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    max-width: 900px;
    margin: 0 auto;
}

.skill-category h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    transition: var(--transition);
}

.skill-list {
    list-style: none;
    color: var(--text-secondary);
    line-height: 1.25;
    transition: var(--transition);
}

.filter-buttons {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
}

.filter-btn {
    padding: 8px 20px;
    background: transparent;
    border: 2px solid var(--border-color);
    color: var(--text-color);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
    font-size: 0.95rem;
    border-radius: 4px;
}

.filter-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.filter-btn.active {
    background: var(--accent);
    color: #ffffff;
    border-color: var(--accent);
}

.article-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: var(--spacing-md);
    transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    display: block;
    border-radius: 6px;
}

.article-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--card-shadow);
    border-color: var(--accent);
}

.article-date {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.article-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-color);
}

.article-excerpt {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
    margin-bottom: var(--spacing-sm);
}

.contact-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    transition: var(--transition);
    line-height: 1.7;
}

.contact-icons {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    align-items: center;
    flex-wrap: wrap;
}

.contact-icon {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--text-color);
    transition: transform 0.2s ease, color 0.2s ease;
}

.contact-icon:hover {
    color: var(--accent);
    transform: translateY(-4px);
}

.contact-icon svg {
    width: 32px;
    height: 32px;
    fill: currentColor;
}

.contact-icon span {
    font-size: 0.875rem;
    font-weight: 500;
}

footer {
    padding: var(--spacing-lg) 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
    background: var(--bg-color);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.footer-links a {
    color: var(--text-secondary);
    transition: color 0.15s ease;
}

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

.footer-links a:focus {
    outline: 2px solid var(--accent);
    outline-offset: 4px;
}

.footer-links svg {
    width: 20px;
    height: 20px;
    fill: currentColor;
}

.copyright {
    color: var(--text-secondary);
    font-size: 0.875rem;
    transition: var(--transition);
}

.hidden {
    display: none !important;
}

*:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    :root {
        --spacing-xl: 40px;
        --spacing-lg: 32px;
    }

    .container {
        padding: 0 var(--spacing-sm);
    }

    /* Hamburger menu */
    .hamburger {
        display: flex;
    }

    nav ul {
        display: none;
    }

    .mobile-menu {
        display: flex;
    }

    section {
        padding: var(--spacing-lg) 0;
    }

    .projects-grid, .articles-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .skills-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .filter-buttons {
        justify-content: stretch;
    }

    .filter-btn {
        flex: 1;
        min-width: 100px;
    }

    .contact-icons {
        gap: var(--spacing-md);
    }

    h1 {
        font-size: clamp(2rem, 6vw, 3.5rem);
    }

    .subtitle {
        font-size: 1rem;
        line-height: 1.6;
        padding: 0 var(--spacing-sm);
    }

    .cta-group {
        flex-direction: column;
        align-items: center;
    }

    .theme-toggle {
        width: 48px;
        height: 24px;
        transform: none; /* Reset nudge on mobile */
    }

    .toggle-slider {
        width: 16px;
        height: 16px;
    }

    .theme-toggle.active .toggle-slider {
        transform: translateX(24px);
    }

    .toggle-icon {
        width: 10px;
        height: 10px;
    }

    table {
        font-size: 0.875rem;
        overflow-x: auto;
        display: block;
    }

    .project, .article-card {
        padding: var(--spacing-md) 0;
    }

    /* Case study mobile h2 clamp preserved */
    h2 {
        font-size: clamp(1.5rem, 3vw, 1.75rem);
    }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}