/* ===== CSS Variables ===== */
:root {
    --color-bg: #F0EEE6;
    --color-text: #141413;
    --color-text-secondary: #5A5A58;
    --color-text-muted: #8A8A88;
    
    --color-primary: #D97757;
    --color-primary-dark: #C25D3F;
    --color-primary-light: #E59173;
    
    --color-accent: #E3DACC;
    --color-accent-dark: #D4C9B8;
    --color-accent-light: #EDE7DC;
    
    --color-button: #141413;
    --color-button-hover: #3A3A38;
    
    --color-border: #D9D5CA;
    --color-border-light: #E3DACC;
    --color-hover: #E8E4DA;
    --color-card-bg: #FFFFFF;
    --color-section-bg: #F5F3EB;
    
    --font-sans: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', 'Roboto', 'Helvetica Neue', sans-serif;
    --font-serif: 'Georgia', 'Merriweather', 'Times New Roman', serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', 'Monaco', 'Consolas', monospace;
    
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    --max-width: 1200px;
    --border-radius: 8px;
    
    --transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: all 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

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

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

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background-color: var(--color-bg);
    background-image: 
        linear-gradient(rgba(217, 119, 87, 0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(217, 119, 87, 0.04) 1px, transparent 1px);
    background-size: 40px 40px;
    background-position: -1px -1px;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
    font-size: 16px;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-sans);
    font-weight: 600;
    line-height: 1.3;
    letter-spacing: -0.02em;
    transition: var(--transition);
    color: var(--color-text);
}

h1 {
    font-weight: 700;
}

h2 {
    font-weight: 600;
}

h3 {
    font-weight: 600;
}

h1 { font-size: clamp(2rem, 5vw, 3rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2.25rem); }
h3 { font-size: clamp(1.125rem, 3vw, 1.5rem); }

p {
    margin-bottom: 1rem;
}

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

.link {
    color: var(--color-primary);
    border-bottom: 1px solid var(--color-primary);
    padding-bottom: 1px;
    transition: var(--transition);
}

.link:hover {
    color: var(--color-primary-dark);
    border-bottom-color: var(--color-primary-dark);
}

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

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

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

.section-label {
    display: none;
}

.section-title {
    margin-top: 0;
    font-weight: 500;
    font-size: clamp(1.5rem, 4vw, 2rem);
}

/* ===== Navigation ===== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(240, 238, 230, 0.95);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    transition: var(--transition-smooth);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--spacing-sm) var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: var(--font-sans);
    font-weight: 700;
    font-size: 1.125rem;
    letter-spacing: -0.03em;
    color: var(--color-text);
}

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

.nav-links a {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    transition: var(--transition);
    letter-spacing: 0.02em;
    position: relative;
    padding-bottom: 4px;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--color-accent);
    transition: width 0.4s ease;
}

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

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

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-text);
    transition: var(--transition);
}

/* ===== Hero Section ===== */
.hero {
    padding: calc(var(--spacing-xl) + 80px) 0 var(--spacing-xl);
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-title {
    max-width: 900px;
    margin: 0 auto var(--spacing-md);
    font-weight: 300;
    animation: fadeInUp 1s ease-out;
    letter-spacing: -0.02em;
    text-align: left;
}

.hero-title .highlight {
    color: var(--color-primary);
    font-weight: 700;
    text-decoration: underline;
    text-decoration-color: var(--color-primary);
    text-decoration-thickness: 3px;
    text-underline-offset: 6px;
}

.hero-subtitle {
    max-width: 900px;
    margin: 0 auto var(--spacing-lg);
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: var(--color-text-secondary);
    animation: fadeInUp 0.8s ease-out 0.2s both;
    text-align: left;
}

.hero-cta {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

/* ===== Buttons ===== */
.btn {
    display: inline-block;
    font-family: var(--font-mono);
    padding: 0.875rem 1.75rem;
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 0.03em;
    border-radius: 6px;
    transition: var(--transition-smooth);
    cursor: pointer;
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    transform: translate(-50%, -50%);
    transition: width 0.6s ease, height 0.6s ease;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

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

.btn-primary:hover {
    background: var(--color-button-hover);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(20, 20, 19, 0.25);
}

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

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

/* ===== About Section ===== */
.about {
    background: var(--color-bg);
    border-top: 1px solid var(--color-border);
}

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

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

.lead {
    font-size: 1.0625rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
    line-height: 1.7;
}

.subsection-title {
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    font-size: 1rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-family: var(--font-mono);
    color: var(--color-primary);
}

.focus-list {
    list-style: none;
    margin-top: var(--spacing-md);
}

.focus-list li {
    padding-left: 1.5rem;
    position: relative;
    margin-bottom: var(--spacing-sm);
    font-size: 1.0625rem;
    line-height: 1.7;
}

.focus-list li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: 700;
    font-size: 1.2em;
}

/* ===== Research Section ===== */
.research {
    border-top: 1px solid var(--color-border);
}

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

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

.research-list {
    list-style: none;
    padding: 0;
    margin-top: var(--spacing-md);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.research-list li {
    padding-left: 1.5rem;
    position: relative;
    line-height: 1.7;
    font-size: 1.0625rem;
    color: var(--color-text-secondary);
}

.research-list li::before {
    content: '—';
    position: absolute;
    left: 0;
    top: 0;
    color: var(--color-primary);
    font-weight: normal;
    font-size: 1em;
}

/* ===== Vision Section ===== */
.vision {
    border-top: 1px solid var(--color-border);
}

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

.vision-content p.lead {
    font-size: 1.0625rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
    line-height: 1.7;
}

.vision-content p {
    font-size: 1.125rem;
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
    font-weight: 300;
}

/* ===== Interests Grid ===== */
.interests {
    border-top: 1px solid var(--color-border);
}

.interests-grid {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.interest-card {
    padding: 0;
    background: transparent;
    border: none;
    transition: var(--transition);
}

.interest-card h3 {
    margin: 0 0 var(--spacing-xs) 0;
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-text);
    text-decoration: underline;
    text-decoration-color: var(--color-primary);
    text-decoration-thickness: 2px;
    text-underline-offset: 4px;
}

.interest-card p {
    margin: 0;
    color: var(--color-text-secondary);
    line-height: 1.6;
    font-size: 1rem;
}

/* ===== Work Section ===== */
.work {
    background: var(--color-section-bg);
    border-top: 1px solid var(--color-border);
}

.work-list {
    list-style: none;
    margin-top: var(--spacing-lg);
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.work-item {
    padding: 0;
    transition: var(--transition);
}

.work-link {
    color: var(--color-text);
    font-size: 1.125rem;
    font-weight: 400;
    transition: var(--transition);
    border-bottom: 1px solid var(--color-primary);
    padding-bottom: 2px;
}

.work-link:hover {
    color: var(--color-primary);
    border-bottom-width: 2px;
}

.work-conference {
    margin-left: 0.5rem;
    font-size: 1rem;
    color: var(--color-text-secondary);
    font-style: italic;
}

.work-footer {
    margin-top: var(--spacing-lg);
    text-align: left;
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
}

/* ===== Quote Section ===== */
.quote-section {
    background: var(--color-section-bg);
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

.quote {
    max-width: 700px;
    margin: 0;
    font-family: var(--font-serif);
    font-size: clamp(1.0625rem, 3vw, 1.25rem);
    font-style: italic;
    text-align: left;
    line-height: 1.8;
    font-weight: 400;
    color: var(--color-text-secondary);
    position: relative;
    padding: var(--spacing-md) 0;
    border-left: 3px solid var(--color-primary);
    padding-left: var(--spacing-md);
}

/* ===== Contact Section ===== */
.contact {
    border-top: 1px solid var(--color-border);
}

.contact-content {
    max-width: 900px;
    margin: 0;
    text-align: left;
}

.contact-text {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text-secondary);
    font-weight: 300;
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    align-items: flex-start;
}

.contact-email {
    font-size: 1.0625rem;
    color: var(--color-text);
    transition: var(--transition);
    border-bottom: 1px solid var(--color-primary);
    padding-bottom: 2px;
}

.contact-email:hover {
    color: var(--color-primary);
    border-bottom-width: 2px;
}

/* ===== Footer ===== */
.footer {
    background: var(--color-section-bg);
    padding: var(--spacing-lg) 0;
    border-top: 2px solid var(--color-border);
}

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

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

.footer-links a {
    font-family: var(--font-mono);
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    letter-spacing: 0.02em;
    font-weight: 500;
    text-transform: uppercase;
}

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

.footer-copyright {
    font-family: var(--font-mono);
    color: var(--color-text-secondary);
    font-size: 0.75rem;
    letter-spacing: 0.05em;
    font-weight: 400;
}

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

/* ===== Responsive Design ===== */
@media (max-width: 768px) {
    :root {
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }
    
    .nav-links {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .nav-links.active {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-bg);
        border-bottom: 1px solid var(--color-border);
        padding: var(--spacing-md);
        gap: var(--spacing-sm);
    }
    
    .hero {
        min-height: 70vh;
        padding: calc(var(--spacing-lg) + 80px) 0 var(--spacing-lg);
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        text-align: center;
    }
    
    .interests-grid,
    .work-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    html {
        font-size: 14px;
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
}

/* Scroll to Top Button */
.scroll-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 48px;
    height: 48px;
    background: var(--color-primary);
    color: var(--color-bg);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    z-index: 1000;
}

.scroll-to-top:hover {
    background: var(--color-text);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.15);
}

.scroll-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.scroll-to-top svg {
    width: 24px;
    height: 24px;
}

@media (max-width: 768px) {
    .scroll-to-top {
        bottom: 1.5rem;
        right: 1.5rem;
        width: 44px;
        height: 44px;
    }
}