/* ==========================================================================
   Ralf D. Müller - Personal Website
   Modern, Clean Design
   Version: 1.0.0
   ========================================================================== */

/* --------------------------------------------------------------------------
   CSS Variables
   -------------------------------------------------------------------------- */
:root {
    /* Colors */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-secondary: #64748b;
    --color-accent: #0ea5e9;

    --color-text: #1e293b;
    --color-text-light: #64748b;
    --color-text-muted: #94a3b8;

    --color-bg: #ffffff;
    --color-bg-alt: #f8fafc;
    --color-bg-dark: #0f172a;

    --color-border: #e2e8f0;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-base: 1rem;
    --font-size-sm: 0.875rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    --font-size-5xl: 3.5rem;

    --line-height-tight: 1.25;
    --line-height-normal: 1.6;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 6rem;

    /* Layout */
    --container-max: 1200px;
    --container-padding: 1.5rem;

    /* Effects */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    --transition-fast: 150ms ease;
    --transition-normal: 200ms ease;
    --transition-slow: 300ms ease;
}

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

* {
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img, picture, video, canvas, svg {
    display: block;
    max-width: 100%;
}

input, button, textarea, select {
    font: inherit;
}

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

a:hover {
    color: var(--color-primary-dark);
}

ul, ol {
    list-style: none;
}

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

.section {
    padding: var(--spacing-4xl) 0;
}

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

.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

.section-intro {
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    max-width: 600px;
    margin-bottom: var(--spacing-2xl);
}

.section-cta {
    margin-top: var(--spacing-2xl);
    text-align: center;
}

/* --------------------------------------------------------------------------
   Navigation
   -------------------------------------------------------------------------- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
}

.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

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

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

.nav-links {
    display: flex;
    gap: var(--spacing-xl);
}

.nav-links a {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-light);
    transition: color var(--transition-fast);
}

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

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
}

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

/* --------------------------------------------------------------------------
   Hero Section
   -------------------------------------------------------------------------- */
.hero {
    padding-top: calc(72px + var(--spacing-4xl));
    padding-bottom: var(--spacing-4xl);
    background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-alt) 100%);
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
}

.hero-subtitle {
    font-size: var(--font-size-lg);
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.hero h1 {
    font-size: var(--font-size-5xl);
    font-weight: 700;
    line-height: var(--line-height-tight);
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

.hero-description {
    font-size: var(--font-size-xl);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xl);
    max-width: 500px;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.hero-image {
    display: flex;
    justify-content: center;
}

.profile-placeholder {
    width: 350px;
    height: 350px;
    border-radius: var(--radius-xl);
    background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-primary) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: var(--font-size-xl);
    font-weight: 500;
    box-shadow: var(--shadow-xl);
}

.profile-photo {
    width: 350px;
    height: 350px;
    border-radius: var(--radius-xl);
    object-fit: cover;
    box-shadow: var(--shadow-xl);
}

/* --------------------------------------------------------------------------
   Buttons
   -------------------------------------------------------------------------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: var(--font-size-base);
    font-weight: 500;
    border-radius: var(--radius-md);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

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

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

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

.btn-small {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-sm);
}

/* --------------------------------------------------------------------------
   About Section
   -------------------------------------------------------------------------- */
.about-content {
    max-width: 700px;
}

.about-text p {
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
}

.skills-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-xl);
}

.skills-list li {
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-light);
}

/* --------------------------------------------------------------------------
   Talks Section
   -------------------------------------------------------------------------- */
.talks-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.talk-card {
    background-color: var(--color-bg);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
}

.talk-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.talk-meta {
    margin-bottom: var(--spacing-md);
}

.talk-type {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-primary);
    color: white;
    font-size: var(--font-size-sm);
    font-weight: 500;
    border-radius: var(--radius-sm);
}

.talk-card h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.talk-card p {
    color: var(--color-text-light);
}

.talk-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.talk-links .btn {
    background-color: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    color: var(--color-text);
}

.talk-links .btn:hover {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

/* --------------------------------------------------------------------------
   Video Lightbox
   -------------------------------------------------------------------------- */
.video-lightbox {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 2000;
    background-color: rgba(0, 0, 0, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.video-lightbox.active {
    opacity: 1;
    visibility: visible;
}

.video-lightbox-content {
    position: relative;
    width: 90%;
    max-width: 1000px;
}

.video-lightbox-close {
    position: absolute;
    top: -50px;
    right: 0;
    background: none;
    border: none;
    color: white;
    font-size: 40px;
    cursor: pointer;
    padding: var(--spacing-sm);
    line-height: 1;
    transition: color var(--transition-fast);
}

.video-lightbox-close:hover {
    color: var(--color-primary);
}

.video-container {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 */
    height: 0;
    overflow: hidden;
    border-radius: var(--radius-lg);
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

/* --------------------------------------------------------------------------
   Publications Section
   -------------------------------------------------------------------------- */
.publications-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    max-width: 700px;
}

.publication-card {
    display: flex;
    gap: var(--spacing-lg);
    padding: var(--spacing-xl);
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
}

.publication-card:hover {
    background-color: var(--color-bg);
    box-shadow: var(--shadow-md);
}

.publication-icon {
    flex-shrink: 0;
    width: 100px;
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-primary);
    border-radius: var(--radius-md);
    color: white;
}

.publication-icon svg {
    width: 48px;
    height: 48px;
}

.publication-cover {
    flex-shrink: 0;
    width: 100px;
    transition: transform var(--transition-normal);
}

.publication-cover:hover {
    transform: scale(1.05);
}

.publication-cover img {
    width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-md);
}

.publication-cover-logo img {
    box-shadow: none;
    border-radius: 0;
}

.publication-cover-wide {
    width: 180px;
}

.publication-card-featured {
    background-color: var(--color-bg);
    border: 2px solid var(--color-primary);
}

.publication-badge {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-primary);
    color: white;
    font-size: var(--font-size-sm);
    font-weight: 600;
    border-radius: var(--radius-sm);
    margin-right: var(--spacing-sm);
}

.publication-content h3 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.publication-meta {
    font-size: var(--font-size-sm);
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.publication-content p:last-child {
    color: var(--color-text-light);
}

.publication-link {
    display: inline-block;
    margin-top: var(--spacing-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-primary);
}

.publication-link:hover {
    text-decoration: underline;
}

/* --------------------------------------------------------------------------
   Trainings Section
   -------------------------------------------------------------------------- */
.trainings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.training-card {
    position: relative;
    display: flex;
    flex-direction: column;
    padding: var(--spacing-xl);
    background-color: var(--color-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
}

.training-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.training-badge {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-primary);
    color: white;
    font-size: var(--font-size-sm);
    font-weight: 600;
    border-radius: var(--radius-sm);
}

.training-card h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
    padding-right: 80px;
}

.training-card > p {
    flex: 1;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
}

.training-meta {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-border);
}

.training-duration,
.training-price {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-light);
}

.training-price {
    color: var(--color-primary);
}

/* --------------------------------------------------------------------------
   Conferences Section
   -------------------------------------------------------------------------- */
.conference-logos {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--spacing-lg);
}

.conference-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-md);
    padding: var(--spacing-xl);
    min-height: 140px;
    background-color: var(--color-bg);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-lg);
    text-decoration: none;
    transition: all var(--transition-normal);
}

.conference-card:hover {
    border-color: var(--color-primary);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.conf-logo {
    height: 50px;
    width: auto;
    max-width: 150px;
    object-fit: contain;
}

.conf-logo-inverted {
    height: 50px;
    width: auto;
    max-width: 150px;
    object-fit: contain;
    background-color: var(--color-bg-dark);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
}

.conf-logo-placeholder {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text);
    text-align: center;
}

.conf-location {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    text-align: center;
}

.conf-stats {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
}

.conf-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 2px 8px;
    background-color: var(--color-primary);
    color: white;
    font-size: var(--font-size-xs);
    font-weight: 600;
    border-radius: var(--radius-full);
}

.conf-years {
    font-size: var(--font-size-xs);
    color: var(--color-text-light);
}

/* Conference Lightbox */
.conf-lightbox {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 1000;
    background-color: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.conf-lightbox.visible {
    opacity: 1;
    visibility: visible;
}

.conf-lightbox-content {
    background-color: var(--color-bg);
    border-radius: var(--radius-lg);
    max-width: 600px;
    width: 100%;
    max-height: 80vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-xl);
}

.conf-lightbox-header {
    padding: var(--spacing-xl);
    border-bottom: 1px solid var(--color-border);
    text-align: center;
}

.conf-lightbox-header img {
    margin-bottom: var(--spacing-md);
}

.conf-lightbox-header h3 {
    margin: 0 0 var(--spacing-sm) 0;
    font-size: var(--font-size-xl);
}

.conf-lightbox-header p {
    margin: 0;
    color: var(--color-text-light);
}

.conf-lightbox-header a {
    color: var(--color-primary);
}

.conf-lightbox-body {
    padding: var(--spacing-lg);
    overflow-y: auto;
    flex: 1;
}

.conf-talks-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.conf-talks-list li {
    display: flex;
    align-items: baseline;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--color-border);
    line-height: 1.5;
}

.conf-talks-list li:last-child {
    border-bottom: none;
}

.conf-talks-list .talk-date {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    white-space: nowrap;
    flex-shrink: 0;
    background: none !important;
    width: auto !important;
    height: auto !important;
    display: inline !important;
    padding: 0;
    border-radius: 0;
}

.conf-talks-list .talk-type {
    display: inline-block;
    padding: 2px 6px;
    background-color: var(--color-primary);
    color: white;
    font-size: var(--font-size-xs);
    border-radius: var(--radius-sm);
    white-space: nowrap;
    flex-shrink: 0;
}

.conf-talks-list .talk-title {
    flex: 1;
}

.conf-talks-list a {
    color: var(--color-text);
    text-decoration: none;
}

.conf-talks-list a:hover {
    color: var(--color-primary);
}

.conf-talks-list .video-link {
    color: var(--color-primary);
    font-size: var(--font-size-sm);
    margin-left: var(--spacing-sm);
}

/* --------------------------------------------------------------------------
   Stream Section - Video Grid
   -------------------------------------------------------------------------- */
.episodes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-2xl);
}

.episode-card {
    display: block;
    text-decoration: none;
    border-radius: var(--radius-lg);
    overflow: hidden;
    background-color: var(--color-bg-alt);
    transition: all var(--transition-normal);
}

.episode-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.episode-thumbnail {
    position: relative;
    aspect-ratio: 16 / 9;
    overflow: hidden;
    background-color: var(--color-bg-dark);
}

.episode-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: opacity var(--transition-normal);
}

.episode-thumbnail .thumb-hover {
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
}

.episode-card:hover .thumb-default {
    opacity: 0;
}

.episode-card:hover .thumb-hover {
    opacity: 1;
}

.episode-badge {
    position: absolute;
    top: var(--spacing-sm);
    left: var(--spacing-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-primary);
    color: white;
    font-size: var(--font-size-sm);
    font-weight: 700;
    border-radius: var(--radius-sm);
}

.play-icon {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background-color: rgba(0, 0, 0, 0.7);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: all var(--transition-normal);
}

.play-icon svg {
    width: 30px;
    height: 30px;
    color: white;
    margin-left: 4px;
}

.episode-card:hover .play-icon {
    opacity: 1;
    background-color: var(--color-primary);
}

.episode-info {
    padding: var(--spacing-lg);
}

.episode-info h4 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.episode-info p {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

@media (max-width: 640px) {
    .episodes-grid {
        grid-template-columns: 1fr;
    }
}

/* --------------------------------------------------------------------------
   Talk Events
   -------------------------------------------------------------------------- */
.talk-events {
    margin-top: var(--spacing-sm);
    font-size: var(--font-size-sm);
    color: var(--color-primary);
    font-weight: 500;
}

/* --------------------------------------------------------------------------
   Contact Section
   -------------------------------------------------------------------------- */
.contact-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-2xl);
}

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

.social-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    font-weight: 500;
    transition: all var(--transition-fast);
}

.social-link:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    box-shadow: var(--shadow-sm);
}

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

.contact-email {
    text-align: left;
}

.contact-email p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
}

.email-link {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--color-primary);
}

.email-link:hover {
    text-decoration: underline;
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.footer {
    padding: var(--spacing-xl) 0;
    background-color: var(--color-bg-dark);
    color: var(--color-text-muted);
}

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

.footer-nav {
    display: flex;
    gap: var(--spacing-lg);
}

.footer-nav a {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

.footer-nav a:hover {
    color: white;
}

/* --------------------------------------------------------------------------
   Responsive Design
   -------------------------------------------------------------------------- */
@media (max-width: 968px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-description {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-cta {
        justify-content: center;
    }

    .hero-image {
        order: -1;
    }

    .profile-placeholder {
        width: 280px;
        height: 280px;
    }
}

@media (max-width: 768px) {
    :root {
        --font-size-5xl: 2.5rem;
        --font-size-3xl: 1.75rem;
    }

    .nav-links {
        display: none;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .hero h1 {
        font-size: var(--font-size-4xl);
    }

    .section {
        padding: var(--spacing-3xl) 0;
    }

    .talks-grid {
        grid-template-columns: 1fr;
    }

    .publication-card {
        flex-direction: column;
        text-align: center;
    }

    .publication-icon {
        margin: 0 auto;
    }

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

    .footer .container {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-cta {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    .social-link {
        flex: 1;
        min-width: 140px;
        justify-content: center;
    }
}

/* --------------------------------------------------------------------------
   Mobile Menu Active State
   -------------------------------------------------------------------------- */
@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background-color: var(--color-bg);
        flex-direction: column;
        padding: var(--spacing-xl);
        gap: var(--spacing-lg);
        border-bottom: 1px solid var(--color-border);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-normal);
    }

    .nav-links.active {
        display: flex;
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

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

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

    .mobile-menu-btn.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }
}

/* --------------------------------------------------------------------------
   Animations
   -------------------------------------------------------------------------- */
.animate {
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate.hidden {
    opacity: 0;
    transform: translateY(20px);
}

.animate.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Stagger animation for cards */
.talk-card:nth-child(1) { transition-delay: 0.1s; }
.talk-card:nth-child(2) { transition-delay: 0.2s; }
.talk-card:nth-child(3) { transition-delay: 0.3s; }

.social-link:nth-child(1) { transition-delay: 0.1s; }
.social-link:nth-child(2) { transition-delay: 0.2s; }
.social-link:nth-child(3) { transition-delay: 0.3s; }

/* --------------------------------------------------------------------------
   Page Content (Subpages)
   -------------------------------------------------------------------------- */
.page-content {
    padding-top: calc(72px + var(--spacing-3xl));
    padding-bottom: var(--spacing-4xl);
    min-height: calc(100vh - 200px);
}

.page-content h1 {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--spacing-2xl);
    color: var(--color-text);
}

.legal-section {
    margin-bottom: var(--spacing-2xl);
}

.legal-section h2 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.legal-section h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.legal-section p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

.legal-section ul {
    margin-left: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    list-style: disc;
}

.legal-section li {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xs);
}

/* --------------------------------------------------------------------------
   Talks Page
   -------------------------------------------------------------------------- */
.page-intro {
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    max-width: 700px;
    margin-bottom: var(--spacing-3xl);
}

/* --------------------------------------------------------------------------
   Year Tabs
   -------------------------------------------------------------------------- */
.booking-cta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg) var(--spacing-xl);
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-2xl);
}

.booking-cta p {
    margin: 0;
    font-size: var(--font-size-lg);
    font-weight: 500;
    color: var(--color-text);
}

@media (max-width: 640px) {
    .booking-cta {
        flex-direction: column;
        text-align: center;
    }
}

.year-tabs {
    margin-bottom: var(--spacing-3xl);
}

.tabs-nav {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--color-border);
}

.tab-btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    background: none;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-text-light);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.tab-btn.active {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.talks-section {
    margin-bottom: var(--spacing-3xl);
}

.talks-section h2 {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--color-border);
}

.talks-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.talk-item {
    display: flex;
    gap: var(--spacing-xl);
    padding: var(--spacing-xl);
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
}

.talk-item:hover {
    background-color: var(--color-bg);
    box-shadow: var(--shadow-md);
}

.talk-date {
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 80px;
    background-color: var(--color-primary);
    color: white;
    border-radius: var(--radius-md);
    text-align: center;
}

.talk-date .day {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    line-height: 1;
}

.talk-date .month {
    font-size: var(--font-size-sm);
    font-weight: 500;
    text-transform: uppercase;
}

.talk-date .year {
    font-size: var(--font-size-sm);
    opacity: 0.8;
}

.talk-logo {
    flex-shrink: 0;
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-bg);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
}

.talk-conf-logo {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.talk-conf-logo.conf-logo-inverted {
    background-color: var(--color-bg-dark);
    padding: var(--spacing-xs);
    border-radius: var(--radius-sm);
}

.talk-info {
    flex: 1;
}

.talk-info .talk-type {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    font-weight: 500;
    border-radius: var(--radius-sm);
    margin-bottom: var(--spacing-sm);
}

.talk-info h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.talk-event {
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.talk-description {
    color: var(--color-text-light);
}

.talk-item .talk-links {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-sm);
}

.talk-item .talk-links a {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-light);
    transition: all var(--transition-fast);
}

.talk-item .talk-links a:hover {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

.talks-cta {
    text-align: center;
    padding: var(--spacing-3xl);
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-xl);
}

.talks-cta h2 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-md);
}

.talks-cta p {
    color: var(--color-text-light);
    max-width: 500px;
    margin: 0 auto var(--spacing-xl);
}

@media (max-width: 640px) {
    .talk-item {
        flex-direction: column;
        text-align: center;
    }

    .talk-date {
        margin: 0 auto;
    }

    .talk-logo {
        margin: 0 auto;
    }
}

/* --------------------------------------------------------------------------
   HHGDAC / Series Page
   -------------------------------------------------------------------------- */
.series-info {
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-3xl);
}

.series-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.series-badge {
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-primary);
    color: white;
    font-size: var(--font-size-sm);
    font-weight: 600;
    border-radius: var(--radius-sm);
}

.series-publication {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

.series-info > p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
}

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

.episodes-section {
    margin-bottom: var(--spacing-3xl);
}

.episodes-section h2 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-sm);
}

.section-subtitle {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xl);
}

.episode-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.episode-item {
    display: flex;
    gap: var(--spacing-xl);
    padding: var(--spacing-xl);
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
}

.episode-item:hover {
    background-color: var(--color-bg);
    box-shadow: var(--shadow-md);
}

.episode-number {
    flex-shrink: 0;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-primary);
    color: white;
    font-size: var(--font-size-2xl);
    font-weight: 700;
    border-radius: var(--radius-md);
}

.episode-content {
    flex: 1;
}

.episode-date {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-xs);
}

.episode-content h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.episode-content p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
}

.episode-link {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-primary);
}

.episode-link:hover {
    text-decoration: underline;
}

.related-section h2 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-xl);
}

.related-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.related-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg);
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    text-decoration: none;
    transition: all var(--transition-normal);
}

.related-card:hover {
    background-color: var(--color-bg);
    box-shadow: var(--shadow-md);
}

.related-card img {
    width: 60px;
    height: auto;
    border-radius: var(--radius-sm);
}

.related-icon {
    flex-shrink: 0;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-primary);
    border-radius: var(--radius-md);
    color: white;
}

.related-icon svg {
    width: 28px;
    height: 28px;
}

.related-info h3 {
    font-size: var(--font-size-lg);
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.related-info p {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

@media (max-width: 640px) {
    .episode-item {
        flex-direction: column;
        text-align: center;
    }

    .episode-number {
        margin: 0 auto;
    }
}

/* --------------------------------------------------------------------------
   Blog Page
   -------------------------------------------------------------------------- */
.blog-filters {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-2xl);
}

.filter-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    background: none;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-light);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.filter-btn.active {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

.blog-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.blog-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
    padding: var(--spacing-xl);
    background-color: var(--color-bg-alt);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
}

.blog-item:hover {
    background-color: var(--color-bg);
    box-shadow: var(--shadow-md);
}

.blog-icon {
    flex-shrink: 0;
    width: 120px;
    height: 80px;
    border-radius: var(--radius-md);
    overflow: hidden;
    background-color: var(--color-bg);
}

.blog-icon img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.blog-date {
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 80px;
    padding: var(--spacing-md);
    background-color: var(--color-bg);
    border-radius: var(--radius-md);
    text-align: center;
}

.blog-date .day {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    line-height: 1;
    color: var(--color-primary);
}

.blog-date .month {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-light);
    text-transform: uppercase;
}

.blog-date .year {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}

.blog-content {
    flex: 1;
}

.blog-meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.blog-tag {
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-bg);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

.lang-badge {
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--color-primary);
    color: white;
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 600;
}

.blog-content h2 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
}

.blog-content h2 a {
    color: var(--color-text);
    text-decoration: none;
}

.blog-content h2 a:hover {
    color: var(--color-primary);
}

.blog-content > p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
}

.blog-link {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-primary);
}

.blog-link:hover {
    text-decoration: underline;
}

@media (max-width: 640px) {
    .blog-filters {
        flex-wrap: nowrap;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
        -ms-overflow-style: none;
        padding-bottom: var(--spacing-sm);
        margin-left: calc(-1 * var(--spacing-md));
        margin-right: calc(-1 * var(--spacing-md));
        padding-left: var(--spacing-md);
        padding-right: var(--spacing-md);
    }

    .blog-filters::-webkit-scrollbar {
        display: none;
    }

    .filter-btn {
        flex-shrink: 0;
        white-space: nowrap;
    }

    .blog-item {
        flex-direction: column;
        text-align: center;
    }

    .blog-icon {
        width: 100%;
        height: 120px;
        margin: 0 auto var(--spacing-md);
    }

    .blog-date {
        margin: 0 auto;
    }

    .blog-meta {
        justify-content: center;
    }
}

/* --------------------------------------------------------------------------
   Article Page
   -------------------------------------------------------------------------- */
.article-page {
    padding-top: calc(72px + var(--spacing-3xl));
    padding-bottom: var(--spacing-4xl);
}

.article-header {
    max-width: 800px;
    margin-bottom: var(--spacing-2xl);
}

.article-header .article-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.article-date {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
}

.article-header h1 {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    line-height: var(--line-height-tight);
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.article-subtitle {
    font-size: var(--font-size-xl);
    color: var(--color-text-light);
}

.article-hero {
    max-width: 800px;
    margin-bottom: var(--spacing-2xl);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.article-hero img {
    width: 100%;
    height: auto;
}

.article-content {
    max-width: 700px;
    font-size: var(--font-size-lg);
    line-height: 1.8;
}

.article-content .lead {
    font-size: var(--font-size-xl);
    color: var(--color-text);
    font-weight: 500;
    margin-bottom: var(--spacing-xl);
}

.article-content h2 {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.article-content h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.article-content p {
    margin-bottom: var(--spacing-lg);
    color: var(--color-text-light);
}

.article-content ul,
.article-content ol {
    margin-bottom: var(--spacing-lg);
    padding-left: var(--spacing-xl);
}

.article-content ul {
    list-style: disc;
}

.article-content ol {
    list-style: decimal;
}

.article-content li {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-light);
}

.article-content blockquote {
    margin: var(--spacing-xl) 0;
    padding: var(--spacing-lg) var(--spacing-xl);
    background-color: var(--color-bg-alt);
    border-left: 4px solid var(--color-primary);
    border-radius: var(--radius-md);
}

.article-content blockquote p {
    margin-bottom: 0;
    font-size: var(--font-size-lg);
    font-style: italic;
    color: var(--color-text);
}

.article-content blockquote cite {
    display: block;
    margin-top: var(--spacing-sm);
    font-size: var(--font-size-sm);
    font-style: normal;
    color: var(--color-text-light);
}

.article-content a {
    color: var(--color-primary);
    text-decoration: underline;
}

.article-content a:hover {
    color: var(--color-primary-dark);
}

.code-comparison {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
}

.code-bad,
.code-good {
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
}

.code-bad {
    background-color: #fef2f2;
    border: 1px solid #fecaca;
}

.code-good {
    background-color: #f0fdf4;
    border: 1px solid #bbf7d0;
}

.code-label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.code-bad p,
.code-good p {
    margin: 0;
    font-family: monospace;
    font-size: var(--font-size-sm);
}

@media (max-width: 640px) {
    .code-comparison {
        grid-template-columns: 1fr;
    }
}

.article-footer {
    max-width: 700px;
    margin-top: var(--spacing-3xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--color-border);
}

.article-footer .article-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
}

.article-discuss {
    margin-bottom: var(--spacing-xl);
}

.article-nav {
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

.back-link {
    font-weight: 500;
    color: var(--color-text-light);
}

.back-link:hover {
    color: var(--color-primary);
}