/* CSS Variables */
:root {
    --color-primary: #1a1a1a;
    --color-primary-light: #333333;
    --color-accent: #4a4a4a;
    --color-text: #1a1a1a;
    --color-text-light: #555555;
    --color-background: #ffffff;
    --color-background-alt: #f5f5f5;
    --color-border: #e0e0e0;
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --max-width: 900px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --transition-speed: 0.3s;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-background);
}

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

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

h1, h2, h3, h4 {
    line-height: 1.3;
    color: var(--color-primary);
}

/* Page Layout */
.page-wrapper {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-lg);
}

/* Profile Hero */
.profile-hero {
    display: flex;
    gap: var(--spacing-xl);
    align-items: flex-start;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-xl);
    border-bottom: 1px solid var(--color-border);
}

.headshot {
    width: 230px;
    flex-shrink: 0;
    object-fit: cover;
    border-radius: 4px;
    border: 1px solid var(--color-border);
    display: block;
}

.profile-info h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.3rem;
}

.profile-info .title {
    font-size: 1rem;
    color: var(--color-text-light);
    margin-bottom: 0.15rem;
}

.profile-info .institution {
    font-size: 0.95rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
}

.profile-links {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
    align-items: center;
}

.profile-links a {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--color-primary);
    border-bottom: 1px solid var(--color-primary);
    padding-bottom: 1px;
    line-height: 1;
}

.profile-links a:hover {
    color: var(--color-accent);
    border-bottom-color: var(--color-accent);
}

.bio p {
    line-height: 1.7;
    margin-bottom: var(--spacing-sm);
}

.bio p:last-child {
    margin-bottom: 0;
}

/* Sections */
.section {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-xl);
    border-bottom: 1px solid var(--color-border);
}

.section:last-child {
    border-bottom: none;
    margin-bottom: 0;
}

.section h2 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-xs);
    border-bottom: 3px solid var(--color-accent);
    display: inline-block;
}

/* Research Section */
.research-category {
    margin-bottom: var(--spacing-lg);
}

.research-category:last-child {
    margin-bottom: 0;
}

.research-category h3 {
    font-size: 1.1rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.paper {
    background-color: var(--color-background-alt);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

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

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

.paper-info {
    flex: 1;
    min-width: 200px;
}

.paper-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.paper-authors {
    font-size: 0.95rem;
    color: var(--color-text-light);
    font-style: italic;
    margin-bottom: 0.25rem;
}

.paper-status {
    font-size: 0.85rem;
    color: var(--color-accent);
    font-weight: 500;
}

.paper-links {
    display: flex;
    gap: var(--spacing-sm);
    flex-shrink: 0;
}

.paper-link {
    display: inline-block;
    padding: 0.4rem 0.8rem;
    background-color: var(--color-primary);
    color: white;
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: 500;
    transition: background-color var(--transition-speed);
}

.paper-link:hover {
    background-color: var(--color-primary-light);
    color: white;
}

.abstract-toggle {
    background: none;
    border: none;
    color: var(--color-primary);
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    padding: var(--spacing-xs) 0;
    margin-top: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-family);
}

.abstract-toggle:hover {
    color: var(--color-accent);
}

.toggle-icon {
    font-size: 0.7rem;
    transition: transform var(--transition-speed);
    display: inline-block;
}

.abstract-toggle[aria-expanded="true"] .toggle-icon {
    transform: rotate(90deg);
}

.abstract-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-speed) ease-out,
                padding var(--transition-speed) ease-out;
}

.abstract-content.expanded {
    max-height: none;
    padding-top: var(--spacing-sm);
}

.abstract-content p {
    color: var(--color-text-light);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* Work in Progress List */
.wip-list {
    list-style: disc;
    margin-left: 1.5rem;
    margin-top: var(--spacing-sm);
}

.wip-list li {
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

/* Contact Section */
.contact-info p {
    margin-bottom: var(--spacing-sm);
}

.contact-info a {
    color: var(--color-primary);
}

/* Footer */
.footer {
    text-align: center;
    padding: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
    color: var(--color-text-light);
    font-size: 0.9rem;
    max-width: var(--max-width);
    margin: 0 auto;
}

/* Responsive Design */
@media (max-width: 680px) {
    .profile-hero {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: var(--spacing-lg);
    }

    .headshot {
        width: 180px;
    }

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

    .paper-header {
        flex-direction: column;
    }

    .paper-links {
        width: 100%;
    }
}

@media (max-width: 480px) {
    body {
        font-size: 15px;
    }

    .page-wrapper {
        padding: var(--spacing-lg) var(--spacing-sm);
    }

    .section h2 {
        font-size: 1.5rem;
    }

    .profile-info h1 {
        font-size: 1.6rem;
    }
}