/* ===== CSS Variables ===== */
:root {
    /* Typography - Inter for everything (standard academic) */
    --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

    /* Font sizes */
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 2rem;
    --text-4xl: 2.5rem;

    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;

    /* Layout */
    --content-width: 1000px;
    --content-padding: 24px;
    --nav-height: 64px;

    /* Light mode colors (default) */
    --bg-primary: #FFFFFF;
    --bg-secondary: #F5F5F5;
    --bg-tertiary: #E5E5E5;
    --text-primary: #1C1917;
    --text-secondary: #57534E;
    --text-tertiary: #A8A29E;
    --accent: #0F766E;
    --accent-hover: #14B8A6;
    --accent-light: #CCFBF1;
    --border: #E7E5E4;
    --shadow: rgba(0, 0, 0, 0.08);
}

/* Dark mode */
[data-theme="dark"] {
    --bg-primary: #000000;
    --bg-secondary: #111111;
    --bg-tertiary: #222222;
    --text-primary: #f5f5f5;
    --text-secondary: #a0a0a0;
    --text-tertiary: #666666;
    --accent: #14B8A6;
    --accent-hover: #2DD4BF;
    --accent-light: #134E4A;
    --border: #2a2a2a;
    --shadow: rgba(0, 0, 0, 0.3);
}

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

html {
    font-size: 18px;
    scroll-behavior: smooth;
    scroll-padding-top: var(--nav-height);
}

body {
    font-family: var(--font-body);
    font-size: var(--text-base);
    line-height: 1.7;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: background-color 0.3s ease, color 0.3s ease;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    line-height: 1.3;
    color: var(--text-primary);
}

h1 {
    font-size: clamp(var(--text-3xl), 5vw, var(--text-4xl));
    margin-bottom: var(--space-4);
}

h2 {
    font-size: var(--text-2xl);
    margin-top: var(--space-8);
    margin-bottom: var(--space-4);
    padding-bottom: var(--space-3);
    border-bottom: 1px solid var(--border);
}

h3 {
    font-size: var(--text-xl);
    margin-top: var(--space-6);
    margin-bottom: var(--space-3);
}

p {
    margin: 0 0 var(--space-6);
    color: var(--text-primary);
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

strong {
    font-weight: 600;
}

ul, ol {
    margin: var(--space-4) 0 var(--space-6);
    padding-left: var(--space-8);
}

li {
    margin-bottom: var(--space-4);
    line-height: 1.6;
}

li:last-child {
    margin-bottom: 0;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ===== Layout ===== */
.container {
    width: 100%;
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0 var(--content-padding);
}

.section {
    padding: var(--space-16) 0;
}

.section--alt {
    background-color: var(--bg-secondary);
}

/* ===== Site Header / Navigation ===== */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--space-6);
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.header-left {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.header-logo-img {
    height: 32px;
    width: auto;
}

[data-theme="dark"] .header-logo-img--invert {
    filter: invert(1);
}

.header-logo {
    display: flex;
    gap: 0.4em;
    font-family: var(--font-heading);
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
}

.header-logo span {
    letter-spacing: 0.1em;
}

.header-logo:hover {
    color: var(--text-primary);
}

.header-right {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.header-link {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    padding: var(--space-2) var(--space-3);
    transition: color 0.2s ease;
}

.header-link:hover {
    color: var(--text-primary);
    text-decoration: none;
}

.header-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--text-primary);
    text-decoration: none;
    padding: var(--space-2) var(--space-3);
    border-radius: 6px;
    background-color: var(--bg-secondary);
    transition: all 0.2s ease;
}

.header-btn:hover {
    color: var(--text-primary);
    background-color: var(--bg-tertiary);
    text-decoration: none;
}

/* Mobile menu toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 36px;
    height: 36px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 6px;
}

.nav-toggle span {
    display: block;
    width: 100%;
    height: 2px;
    background-color: var(--text-primary);
    transition: all 0.3s ease;
}

/* Mobile menu - hidden by default on desktop */
.mobile-menu {
    display: none;
}

/* ===== Dark Mode Toggle ===== */
#theme-toggle {
    width: 36px;
    height: 36px;
    border: none;
    border-radius: 8px;
    background-color: var(--bg-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s ease;
    font-size: 18px;
}

#theme-toggle:hover {
    background-color: var(--bg-tertiary);
}

[data-theme="light"] .moon-icon,
[data-theme="dark"] .sun-icon {
    display: none;
}

[data-theme="light"] .sun-icon,
[data-theme="dark"] .moon-icon {
    display: inline;
}

/* ===== Main Content ===== */
main {
    padding-top: var(--nav-height);
}

/* ===== Hero Section ===== */
.hero {
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: var(--space-20) var(--content-padding) var(--space-8);
    background-color: var(--bg-primary);
}

.hero__content {
    max-width: 800px;
}

.eyebrow {
    font-family: var(--font-body);
    font-size: var(--text-sm);
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: var(--space-4);
}

.hero__title {
    margin-bottom: var(--space-4);
}

.hero__title--easter-egg .egg {
    transition: color 0.3s ease;
}

.hero__title--easter-egg:hover .egg {
    color: var(--accent);
}

.hero__subtitle {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    margin-bottom: var(--space-8);
    line-height: 1.6;
}

.hero__cta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
    justify-content: center;
}

/* ===== Supported By ===== */
.supported-by {
    margin-top: var(--space-8);
    text-align: center;
    max-width: var(--content-width);
    margin-left: auto;
    margin-right: auto;
}

.supported-by__label {
    font-size: var(--text-sm);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-tertiary);
    margin-bottom: var(--space-6);
}

.supported-by__logos {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-12);
    flex-wrap: nowrap;
}

.supported-by__logos .logo--circular {
    height: clamp(52px, 8vw, 90px);
}

.supported-by__logos img {
    height: clamp(40px, 6vw, 72px);
    max-width: clamp(130px, 18vw, 240px);
    width: auto;
    object-fit: contain;
}

[data-theme="dark"] .supported-by__logos .logo--invert {
    filter: invert(1);
}

[data-theme="dark"] .supported-by__logos .logo--white {
    filter: brightness(0) invert(1);
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    font-family: var(--font-body);
    font-size: var(--text-sm);
    font-weight: 600;
    text-decoration: none;
    border-radius: 50px;
    border: 2px solid transparent;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 2px 8px var(--shadow);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

.btn--primary {
    background-color: var(--text-primary);
    color: var(--bg-primary);
    border-color: var(--text-primary);
}

.btn--primary:hover {
    color: var(--bg-primary);
}

.btn--secondary {
    background-color: transparent;
    color: var(--text-primary);
    border-color: var(--border);
    box-shadow: none;
}

.btn--secondary:hover {
    background-color: var(--bg-secondary);
    box-shadow: none;
}

.btn--disabled {
    background-color: var(--bg-secondary);
    color: var(--text-tertiary);
    border-color: var(--border);
    box-shadow: none;
    cursor: not-allowed;
    opacity: 0.7;
}

.btn--disabled:hover {
    transform: none;
    box-shadow: none;
}

/* ===== Content Sections ===== */
.content-section {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: var(--space-8) var(--content-padding);
}

.content-section h2:first-child {
    margin-top: 0;
}

/* ===== Highlight Box (like TL;DR) ===== */
.highlight-box {
    background-color: var(--bg-secondary);
    border-radius: 12px;
    padding: var(--space-6) var(--space-8);
    margin: var(--space-8) 0;
    border-left: 4px solid var(--accent);
}

.highlight-box h3 {
    margin-top: 0;
    font-size: var(--text-xl);
}

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

/* ===== Cards Grid ===== */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-6);
    margin: var(--space-8) 0;
}

.card {
    background-color: var(--bg-secondary);
    border-radius: 12px;
    padding: var(--space-6);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px var(--shadow);
}

.card h3 {
    margin-top: 0;
    margin-bottom: var(--space-3);
    font-size: var(--text-lg);
}

.card p {
    margin-bottom: 0;
    color: var(--text-secondary);
    font-size: var(--text-sm);
}

/* ===== Timeline ===== */
.timeline {
    margin: var(--space-8) 0;
}

.timeline-row {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-8);
    padding: var(--space-3) 0;
    border-bottom: 1px solid var(--border);
}

.timeline-row:last-child {
    border-bottom: none;
}

.timeline-item {
    display: flex;
    gap: var(--space-4);
}

.timeline-date {
    flex-shrink: 0;
    width: 100px;
    display: flex;
    flex-direction: column;
    color: var(--accent);
}

.timeline-date__day {
    font-weight: 600;
    font-size: var(--text-lg);
    line-height: 1.2;
}

.timeline-date__year {
    font-size: var(--text-sm);
    opacity: 0.8;
}

.timeline-content {
    flex: 1;
}

.timeline-content h4 {
    margin: 0 0 var(--space-1);
    font-family: var(--font-body);
    font-weight: 600;
    font-size: var(--text-base);
}

.timeline-content p {
    margin: 0;
    color: var(--text-secondary);
    font-size: var(--text-sm);
}

/* ===== Team Grid ===== */
.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--space-6);
    margin: var(--space-6) 0;
}

.team-member {
    text-align: center;
    padding: var(--space-4);
}

.team-member__image {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background-color: var(--bg-tertiary);
    margin: 0 auto var(--space-3);
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

.team-member__image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.team-member__image-placeholder {
    color: var(--text-tertiary);
    font-size: var(--text-2xl);
}

.team-member h4 {
    margin: 0 0 var(--space-1);
    font-family: var(--font-body);
    font-weight: 600;
    font-size: var(--text-base);
}

.team-member__role {
    margin: 0 0 var(--space-1);
    color: var(--text-secondary);
    font-size: var(--text-sm);
    font-style: italic;
}

.team-member__institution {
    margin: 0 0 var(--space-2);
    color: var(--text-secondary);
    font-size: var(--text-sm);
}

.team-member__social {
    display: flex;
    justify-content: center;
    gap: var(--space-3);
}

.team-member__social a {
    color: var(--text-tertiary);
    transition: color 0.2s ease;
}

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

.team-member__social svg {
    width: 18px;
    height: 18px;
}

/* Compact team list */
.team-list {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-4);
    margin: var(--space-6) 0 var(--space-4);
}

.team-list__item {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.team-list__name {
    font-family: var(--font-body);
    font-weight: 600;
    font-size: var(--text-base);
    color: var(--text-primary);
}

.team-list__role {
    font-size: var(--text-sm);
    color: var(--text-secondary);
    font-style: italic;
}

.team-list__institution {
    font-size: var(--text-sm);
    color: var(--text-secondary);
}

.team-list__social {
    display: flex;
    gap: var(--space-2);
    margin-top: var(--space-1);
}

.team-list__social a {
    color: var(--text-tertiary);
    transition: color 0.2s ease;
}

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

.team-list__social svg {
    width: 16px;
    height: 16px;
}

@media (max-width: 1024px) {
    .team-list {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .team-list {
        grid-template-columns: 1fr;
    }
}

/* ===== Footer ===== */
.footer {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    padding: var(--space-12) 0 var(--space-6);
    border-top: 1px solid var(--border);
}

.footer__inner {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0 var(--content-padding);
}

.footer__columns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-8);
    padding-bottom: var(--space-8);
    margin-bottom: var(--space-6);
    border-bottom: 1px solid var(--border);
}

.footer__col h4 {
    font-size: var(--text-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-tertiary);
    margin: 0 0 var(--space-4);
}

.footer__links,
.footer__emails {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer__links li,
.footer__emails li {
    margin-bottom: var(--space-2);
}

.footer__links a,
.footer__emails a {
    color: var(--text-secondary);
    font-size: var(--text-sm);
    transition: color 0.2s ease;
}

.footer__links a:hover,
.footer__emails a:hover {
    color: var(--text-primary);
}

.footer__social {
    display: flex;
    gap: var(--space-4);
    margin-top: var(--space-4);
}

.footer__social a {
    color: var(--text-tertiary);
    transition: color 0.2s ease;
}

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

.footer__social svg {
    width: 20px;
    height: 20px;
}

.footer__organized-by {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-4);
    padding: var(--space-6) 0;
}

.footer__organized-by span {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.footer__org-logos {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

.footer__org-logo {
    height: 24px;
    width: auto;
    opacity: 0.7;
}

[data-theme="dark"] .footer__org-logo--invert {
    filter: invert(1);
}

.footer__copyright {
    text-align: center;
    padding-top: var(--space-6);
    color: var(--text-tertiary);
    font-size: var(--text-sm);
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
    html {
        font-size: 17px;
    }

    .site-header {
        padding: 0 var(--space-4);
    }

    .header-right {
        gap: var(--space-2);
    }

    .header-btn {
        padding: var(--space-2);
        font-size: 0;
        gap: 0;
    }

    .header-btn span {
        display: none;
    }

    .nav-toggle {
        display: flex;
    }

    .header-link {
        display: none;
    }

    .header-right .header-btn {
        display: none;
    }

    .header-right #theme-toggle {
        display: flex;
    }

    /* Mobile menu */
    .mobile-menu {
        display: block;
        position: fixed;
        top: var(--nav-height);
        left: 0;
        right: 0;
        background-color: var(--bg-primary);
        border-bottom: 1px solid var(--border);
        padding: var(--space-4);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all 0.3s ease;
        z-index: 999;
    }

    .mobile-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .mobile-menu a {
        display: block;
        padding: var(--space-3) 0;
        color: var(--text-primary);
        font-weight: 500;
        border-bottom: 1px solid var(--border);
    }

    .mobile-menu a:last-child {
        border-bottom: none;
    }

    .hero {
        padding: var(--space-12) var(--content-padding);
    }

    .content-section {
        padding: var(--space-12) var(--content-padding);
    }

    .timeline-row {
        grid-template-columns: 1fr;
    }

    .timeline-item {
        flex-direction: column;
        gap: var(--space-2);
    }

    .timeline-date {
        width: auto;
    }

    .footer__columns {
        grid-template-columns: 1fr;
        gap: var(--space-6);
    }
}

@media (max-width: 480px) {
    html {
        font-size: 16px;
    }

    .hero__cta {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    .supported-by__logos {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        align-items: center;
        gap: var(--space-4) var(--space-6);
    }

    .supported-by__logos img {
        height: 32px;
        max-width: 110px;
    }

    .supported-by__logos .logo--circular {
        height: 44px;
        max-width: none;
    }
}

/* ===== Print Styles ===== */
@media print {
    .site-header,
    #theme-toggle,
    .nav-toggle {
        display: none;
    }

    main {
        padding-top: 0;
    }

    body {
        background: white;
        color: black;
    }
}