:root {
    --color-bg: #0a0a0a;
    --color-bg-light: #1a1a2e;
    --color-text: #ffffff;
    --color-text-muted: #b0b0b0;
    --color-accent: #00BFB3;
    --color-accent-hover: #00a89c;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 3rem;
    --spacing-xl: 4rem;
    --border-radius: 12px;
    --border-radius-lg: 20px;
}

/* Light theme variables */
[data-theme="light"] {
    --color-bg: #ffffff;
    --color-bg-light: #f5f5f5;
    --color-text: #1a1a1a;
    --color-text-muted: #666666;
    --color-accent: #00BFB3;
    --color-accent-hover: #00a89c;
}

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

html {
    scroll-behavior: smooth;
    background: var(--color-bg);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-light) 100%);
    background-attachment: fixed;
    color: var(--color-text);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Geometric Background Pattern */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        linear-gradient(rgba(0, 191, 179, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 191, 179, 0.03) 1px, transparent 1px);
    background-size: 50px 50px;
    pointer-events: none;
    z-index: 0;
}

[data-theme="light"] body::before {
    background-image: 
        linear-gradient(rgba(0, 191, 179, 0.08) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 191, 179, 0.08) 1px, transparent 1px);
}

/* Header & Navigation */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(10, 10, 10, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding: var(--spacing-sm) var(--spacing-md);
}

[data-theme="light"] header {
    background: rgba(255, 255, 255, 0.95);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

nav {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.logo-container img {
    width: 40px;
    height: 40px;
    /* filter: brightness(0) invert(1); */
}

[data-theme="light"] .logo-container img {
    filter: brightness(0);
}

.logo-text {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-accent);
}

/* Hamburger Menu Button */
.menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    gap: 0.25rem;
    min-height: 44px;
    min-width: 44px;
    justify-content: center;
    align-items: center;
    color: var(--color-text);
}

.menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: currentColor;
    transition: all 0.3s ease;
    border-radius: 2px;
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

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

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
    list-style: none;
    align-items: center;
    margin: 0;
    padding: 0;
}

.nav-links li {
    position: relative;
    margin: 0;
    padding: 0;
}

.nav-links a {
    color: var(--color-text-muted);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color 0.3s ease;
    padding: 0.5rem 0;
    display: block;
}

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

.nav-links a[data-lang] {
    display: none;
}

.nav-links a[data-lang].active {
    display: inline-block;
}

.header-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    color: var(--color-text-muted);
    transition: color 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 44px;
    min-height: 44px;
    border-radius: var(--border-radius);
}

.theme-toggle:hover {
    color: var(--color-accent);
    background: rgba(0, 191, 179, 0.1);
}

.theme-icon {
    width: 20px;
    height: 20px;
    transition: opacity 0.3s ease, transform 0.3s ease;
}

/* Show sun icon in dark mode (to switch to light) */
:not([data-theme]) .sun-icon {
    display: block;
}

:not([data-theme]) .moon-icon {
    display: none;
}

/* Show moon icon in light mode (to switch to dark) */
[data-theme="light"] .sun-icon {
    display: none;
}

[data-theme="light"] .moon-icon {
    display: block;
}

.lang-switcher {
    display: flex;
    gap: var(--spacing-xs);
    align-items: center;
}

.lang-switcher-desktop {
    display: flex;
}

.theme-toggle-mobile {
    display: none;
}

.theme-toggle-mobile .theme-toggle {
    width: 100%;
    justify-content: center;
    padding: 0.5rem 0;
    gap: var(--spacing-xs);
    font-size: 0.95rem;
    color: var(--color-text-muted);
}

.theme-toggle-mobile .theme-toggle span[data-lang] {
    display: none;
    font-size: 0.95rem;
}

.theme-toggle-mobile .theme-toggle span[data-lang].active {
    display: inline;
    font-size: 0.95rem;
}

.theme-toggle-desktop {
    display: flex;
}

.lang-switcher-mobile {
    display: none;
}

.lang-switcher-mobile .lang-switcher {
    padding: 0.5rem 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin-top: 0;
    justify-content: center;
}

[data-theme="light"] .lang-switcher-mobile .lang-switcher {
    border-top: 1px solid rgba(0, 0, 0, 0.1);
}

.lang-switcher button,
.lang-btn {
    background: none;
    border: none;
    color: var(--color-text-muted);
    cursor: pointer;
    font-size: 0.9rem;
    padding: 0.25rem 0.5rem;
    transition: color 0.3s ease;
    min-height: 44px;
}

.lang-switcher button:hover,
.lang-btn:hover {
    color: var(--color-accent);
}

.lang-switcher button.active,
.lang-btn.active {
    color: var(--color-accent);
    font-weight: 600;
}

.lang-switcher span {
    color: #666;
}

/* Main Content */
main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    position: relative;
    z-index: 1;
}

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

section:first-of-type {
    padding-top: var(--spacing-lg);
}

/* Hero Section */
#hero {
    text-align: center;
    padding: var(--spacing-xl) 0;
    position: relative;
    background: radial-gradient(ellipse at center, rgba(0, 191, 179, 0.1) 0%, transparent 70%);
}

.hero-logo {
    width: 160px;
    height: 160px;
    margin: 0 auto var(--spacing-md);
    /* filter: brightness(0) invert(1); */
    animation: glow 2s ease-in-out infinite alternate;
}

[data-theme="light"] .hero-logo {
    filter: brightness(0);
    animation: glow-light 2s ease-in-out infinite alternate;
}

@keyframes glow {
    from {
        filter: drop-shadow(0 0 20px rgba(0, 191, 179, 0.4));
    }
    to {
        filter: drop-shadow(0 0 40px rgba(0, 191, 179, 0.7));
    }
}

@keyframes glow-light {
    from {
        filter: brightness(0) drop-shadow(0 0 20px rgba(0, 191, 179, 0.4));
    }
    to {
        filter: brightness(0) drop-shadow(0 0 40px rgba(0, 191, 179, 0.7));
    }
}

h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.hero-subtitle {
    font-size: clamp(1.1rem, 2.5vw, 1.5rem);
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    font-weight: 300;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.hero-tagline {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: var(--color-accent);
    font-weight: 600;
    letter-spacing: 0.1em;
    margin-bottom: var(--spacing-lg);
    text-transform: uppercase;
}

.cta-button {
    display: inline-block;
    padding: 14px 40px;
    min-height: 44px;
    font-size: 1.1rem;
    font-weight: 600;
    color: #ffffff;
    background: var(--color-accent);
    border: none;
    border-radius: 50px;
    text-decoration: none;
    transition: all 0.3s ease;
    box-shadow: 0 8px 20px rgba(0, 191, 179, 0.3);
    cursor: pointer;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 30px rgba(0, 191, 179, 0.5);
    background: var(--color-accent-hover);
}

/* Section Headings */
h2 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.section-icon {
    width: 32px;
    height: 32px;
    color: var(--color-accent);
    flex-shrink: 0;
}

/* Content Blocks */
.content-block {
    margin-bottom: var(--spacing-md);
}

.content-block p {
    font-size: 1.1rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    line-height: 1.8;
}

/* Icon Grid */
.icon-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.icon-card {
    text-align: center;
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--border-radius);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

.icon-card:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--color-accent);
    transform: translateY(-5px);
}

.icon-card svg {
    width: 48px;
    height: 48px;
    margin: 0 auto var(--spacing-sm);
    color: var(--color-accent);
}

.icon-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.icon-card p {
    font-size: 0.95rem;
    color: var(--color-text-muted);
    margin: 0;
}

/* Organizers / Meet the Team Section */
.organizers {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    flex-wrap: wrap;
    justify-content: center;
}

.organizer-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    width: 300px;
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--border-radius-lg);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

[data-theme="light"] .organizer-card {
    background: rgba(0, 0, 0, 0.02);
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.organizer-card:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--color-accent);
    transform: translateY(-5px);
}

.organizer-photo {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--color-accent);
    margin-bottom: var(--spacing-sm);
    transition: all 0.3s ease;
}

.organizer-card:hover .organizer-photo {
    box-shadow: 0 0 20px rgba(0, 191, 179, 0.3);
}

.organizer-name {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
    text-decoration: none;
    transition: color 0.3s ease;
}

.organizer-name:hover {
    color: var(--color-accent);
}

.organizer-headline {
    font-size: 0.95rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    line-height: 1.4;
    white-space: nowrap;
}

.organizer-headline[data-lang] {
    display: none;
}

.organizer-headline[data-lang].active {
    display: block;
}

.organizer-linkedin {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-accent);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

.organizer-linkedin:hover {
    color: var(--color-accent-hover);
}

/* Event Cards */
.event-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.event-card {
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--border-radius);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

[data-theme="light"] .event-card {
    background: rgba(0, 0, 0, 0.02);
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.event-card:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--color-accent);
}

[data-theme="light"] .event-card:hover {
    background: rgba(0, 0, 0, 0.05);
}

.event-card.disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.event-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.event-card p {
    font-size: 0.95rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
}

/* Join Steps */
.join-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.step-card {
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--border-radius);
    border: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    transition: all 0.3s ease;
}

[data-theme="light"] .step-card {
    background: rgba(0, 0, 0, 0.02);
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.step-card:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--color-accent);
}

[data-theme="light"] .step-card:hover {
    background: rgba(0, 0, 0, 0.05);
}

.step-number {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
    margin-bottom: var(--spacing-sm);
}

.step-label {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
    display: none;
}

.step-label.active {
    display: block;
}

.step-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-accent);
    line-height: 1;
}

.step-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.step-card p {
    font-size: 0.95rem;
    color: var(--color-text-muted);
    margin: 0;
}

.join-cta {
    text-align: center;
    margin-top: var(--spacing-lg);
}

/* Buttons */
.button {
    display: inline-block;
    padding: 12px 32px;
    min-height: 44px;
    font-size: 1rem;
    font-weight: 600;
    color: #ffffff;
    background: var(--color-accent);
    border: none;
    border-radius: 50px;
    text-decoration: none;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 191, 179, 0.3);
    cursor: pointer;
    margin: var(--spacing-xs) var(--spacing-xs) var(--spacing-xs) 0;
}

.button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 191, 179, 0.4);
    background: var(--color-accent-hover);
}

.button-secondary {
    background: rgba(0, 191, 179, 0.1);
    border: 1px solid rgba(0, 191, 179, 0.3);
    box-shadow: none;
}

.button-secondary:hover {
    background: rgba(0, 191, 179, 0.2);
}

/* Language Content */
[data-lang] {
    display: none;
}

[data-lang].active {
    display: block;
}

/* Code of Conduct & Contact */
.info-section {
    text-align: center;
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.03);
    border-radius: var(--border-radius);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

[data-theme="light"] .info-section {
    background: rgba(0, 0, 0, 0.02);
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.info-section p {
    font-size: 1rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
}

.info-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-accent);
    text-decoration: none;
    font-size: 1rem;
    font-weight: 600;
    transition: color 0.3s ease;
}

.info-link:hover {
    color: var(--color-accent-hover);
}

.info-link svg {
    width: 20px;
    height: 20px;
}

.contact-feedback {
    font-size: 0.95rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
    font-style: italic;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.contact-email {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-md);
}

.contact-email span[data-lang] {
    display: none;
}

.contact-email span[data-lang].active {
    display: inline;
}

.contact-social {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    margin-top: var(--spacing-md);
}

.social-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-accent);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.3s ease;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    border: 1px solid rgba(0, 191, 179, 0.3);
    background: rgba(0, 191, 179, 0.05);
}

.social-link:hover:not(.disabled) {
    color: var(--color-accent-hover);
    background: rgba(0, 191, 179, 0.1);
    border-color: var(--color-accent);
    transform: translateY(-2px);
}

.social-link.disabled {
    opacity: 0.5;
    cursor: not-allowed;
    border-color: rgba(255, 255, 255, 0.1);
    background: rgba(255, 255, 255, 0.02);
}

.social-link svg {
    width: 20px;
    height: 20px;
}

.social-link.disabled[data-lang] {
    display: none;
}

.social-link.disabled[data-lang].active {
    display: inline-flex;
}

/* Footer */
footer {
    background: rgba(0, 0, 0, 0.3);
    padding: var(--spacing-lg) var(--spacing-md);
    text-align: center;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin-top: var(--spacing-xl);
}

[data-theme="light"] footer {
    background: rgba(0, 0, 0, 0.05);
    border-top: 1px solid rgba(0, 0, 0, 0.1);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
}

.footer-text {
    color: var(--color-text-muted);
    font-size: 0.95rem;
    margin-bottom: var(--spacing-sm);
}

.footer-link {
    color: var(--color-accent);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color 0.3s ease;
    margin: 0 var(--spacing-sm);
}

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

.footer-link[data-lang] {
    display: none;
}

.footer-link[data-lang].active {
    display: inline;
}

/* Responsive */
@media (max-width: 768px) {
    header {
        padding: var(--spacing-sm);
    }

    nav {
        flex-wrap: wrap;
    }

    .menu-toggle {
        display: flex;
        order: 3;
    }

    .nav-links {
        display: none;
        flex-direction: column;
        width: 100%;
        gap: 0;
        padding: 0;
        margin: 0;
        order: 4;
        align-items: center;
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links li {
        width: 100%;
        margin: 0;
        padding: 0;
        text-align: center;
    }

    .nav-links a {
        padding: 0.75rem 0;
        text-align: center;
        display: inline-block;
    }

    .header-controls {
        order: 2;
    }

    .theme-toggle-desktop {
        display: none;
    }

    .theme-toggle-mobile {
        display: block;
        width: 100%;
        margin: 0;
        padding: 0;
    }

    .theme-toggle-mobile .theme-toggle {
        border-top: 1px solid rgba(255, 255, 255, 0.1);
        margin-top: 0;
        padding: 0.75rem 0;
    }

    [data-theme="light"] .theme-toggle-mobile .theme-toggle {
        border-top: 1px solid rgba(0, 0, 0, 0.1);
    }

    .lang-switcher-mobile {
        width: 100%;
        margin: 0;
        padding: 0;
    }

    .lang-switcher-mobile .lang-switcher {
        padding: 0.75rem 0;
    }

    .lang-switcher-desktop {
        display: none;
    }

    .lang-switcher-mobile {
        display: block;
        width: 100%;
    }

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

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

    .icon-grid,
    .join-steps,
    .event-cards {
        grid-template-columns: 1fr;
    }

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

    .organizer-card {
        width: 100%;
        max-width: 100%;
    }

    .organizer-headline {
        white-space: normal;
    }

    .contact-social {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

    .social-link {
        width: 100%;
        justify-content: center;
        max-width: 300px;
    }
}

@media (max-width: 480px) {
    .hero-logo {
        width: 120px;
        height: 120px;
    }

    .hero-tagline {
        font-size: 0.9rem;
    }

    .organizer-card {
        width: 100%;
    }

    .content-block p {
        font-size: 1rem;
    }
}