:root {
    --primary-color: #007aff;
    --primary-dark: #0056b3;
    --text-color: #1d1d1f;
    --text-light: #6e6e73;
    --bg-color: #ffffff;
    --bg-secondary: #f5f5f7;
    --card-bg: #ffffff;
    --border-color: rgba(0,0,0,0.05);
    --gradient-hero: linear-gradient(135deg, #f5f7fa 0%, #e4efff 100%);
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-accent: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --shadow-soft: 0 10px 30px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 20px 40px rgba(0, 0, 0, 0.12);
}

/* Dark Theme Variables */
body.dark-theme {
    --text-color: #f5f5f7;
    --text-light: #a1a1a6;
    --bg-color: #050505;
    --bg-secondary: #121212;
    --card-bg: #1c1c1e;
    --border-color: rgba(255,255,255,0.1);
    --gradient-hero: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
    --shadow-soft: 0 10px 30px rgba(0, 0, 0, 0.5);
    --shadow-hover: 0 20px 40px rgba(0, 0, 0, 0.7);
}

/* Dark Theme Section Backgrounds */
body.dark-theme .abstract-section {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
}

body.dark-theme .dates-section {
    background: linear-gradient(135deg, #0f0f1a 0%, #1a1a2e 100%);
}

body.dark-theme .speakers-section {
    background: linear-gradient(135deg, #1e1e30 0%, #252542 100%);
}

body.dark-theme .track-section:not(.competition-track) {
    background: linear-gradient(135deg, #141428 0%, #1c1c35 100%);
}

body.dark-theme .program-section {
    background: linear-gradient(135deg, #1a1a2e 0%, #1e1e38 100%);
}

body.dark-theme .organizers-section {
    background: linear-gradient(135deg, #0f0f1a 0%, #1a1a2e 100%);
}

/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    -webkit-font-smoothing: antialiased;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

body.dark-theme .navbar {
    background: rgba(18, 18, 18, 0.85);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo h2 {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2.5rem;
    margin-right: 1.5rem;
}

.nav-item {
    position: relative;
}

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.3s ease;
}

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

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background: var(--card-bg);
    border-radius: 12px;
    box-shadow: var(--shadow-soft);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    min-width: 200px;
    padding: 10px 0;
    margin-top: 15px;
    border: 1px solid var(--border-color);
}

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

.dropdown-link {
    display: block;
    padding: 10px 20px;
    color: var(--text-color);
    text-decoration: none;
    transition: background-color 0.2s ease;
}

.dropdown-link:hover {
    background-color: var(--bg-secondary);
    color: var(--primary-color);
}

/* Theme Toggle Button */
.theme-btn {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.2rem;
    padding: 5px;
    border-radius: 50%;
    transition: transform 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-btn:hover {
    transform: scale(1.1);
}

/* Hamburger Button */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    background: none;
    border: none;
    padding: 5px;
    z-index: 1001;
}

.bar {
    width: 25px;
    height: 2px;
    background-color: var(--text-color);
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    padding: 160px 0 100px;
    background: linear-gradient(rgba(255, 255, 255, 0.9), rgba(255, 255, 255, 0.8)), url('images/vienna.png');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
}

body.dark-theme .hero {
    background: linear-gradient(rgba(0, 0, 0, 0.7), rgba(0, 0, 0, 0.8)), url('images/vienna.png');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.hero::before {
    content: '';
    position: absolute;
    top: -10%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.2) 0%, rgba(118, 75, 162, 0.2) 100%);
    filter: blur(80px);
    border-radius: 50%;
    z-index: 0;
    animation: pulse 10s infinite alternate;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -10%;
    left: -10%;
    width: 500px;
    height: 500px;
    background: linear-gradient(135deg, rgba(79, 172, 254, 0.2) 0%, rgba(0, 242, 254, 0.2) 100%);
    filter: blur(80px);
    border-radius: 50%;
    z-index: 0;
    animation: pulse 10s infinite alternate-reverse;
}

@keyframes pulse {
    0% { transform: scale(1); }
    100% { transform: scale(1.1); }
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 4rem;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 4rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    letter-spacing: -1px;
    color: var(--text-color);
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 400;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.hero-meta {
    margin-bottom: 2.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.workshop-date, .workshop-location {
    font-size: 1.1rem;
    color: var(--text-color);
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 14px 32px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    display: inline-block;
    font-size: 1rem;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    box-shadow: 0 4px 15px rgba(0, 122, 255, 0.3);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 122, 255, 0.4);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.8);
    color: var(--primary-color);
    border: 1px solid rgba(0, 122, 255, 0.2);
    backdrop-filter: blur(10px);
}

body.dark-theme .btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border-color: rgba(255, 255, 255, 0.2);
}

.btn-secondary:hover {
    background: white;
    color: #007aff;
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 400px;
}

.hero-graphic {
    position: relative;
    width: 350px;
    height: 350px;
}

.floating-card {
    position: absolute;
    padding: 24px 32px;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    font-weight: 700;
    font-size: 1.2rem;
    color: #1d1d1f; /* Keep dark text on light card even in dark mode */
    animation: float 6s ease-in-out infinite;
    display: flex;
    align-items: center;
    gap: 12px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    transition: transform 0.3s ease;
}

.floating-card:hover {
    transform: scale(1.05) translateY(-5px);
    z-index: 10;
}

.card-icon {
    font-size: 1.5rem;
}

.card-1 {
    top: 0;
    left: 0;
    animation-delay: 0s;
}

.card-2 {
    top: 40%;
    right: -20px;
    animation-delay: 2s;
}

.card-3 {
    bottom: 0;
    left: 40px;
    animation-delay: 4s;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

/* Section Styles */
.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 4rem;
    color: var(--text-color);
}

/* Abstract Section */
.abstract-section {
    padding: 100px 0;
    background: var(--card-bg);
}

.abstract-content {
    max-width: 800px;
    margin: 0 auto;
}

.abstract-content p {
    font-size: 1.15rem;
    color: var(--text-light);
    margin-bottom: 1.75rem;
    line-height: 1.9;
}

.highlight {
    color: var(--text-color);
    font-weight: 600;
    background: linear-gradient(120deg, rgba(79, 172, 254, 0.15) 0%, rgba(102, 126, 234, 0.15) 100%);
    padding: 0.1em 0.35em;
    border-radius: 4px;
    transition: background 0.3s ease;
}

.highlight:hover {
    background: linear-gradient(120deg, rgba(79, 172, 254, 0.3) 0%, rgba(102, 126, 234, 0.3) 100%);
}

.welcome-callout {
    margin-top: 3rem;
    padding: 2.5rem;
    background: linear-gradient(135deg, rgba(79, 172, 254, 0.1) 0%, rgba(102, 126, 234, 0.1) 100%);
    border: 1px solid rgba(79, 172, 254, 0.3);
    border-radius: 20px;
    text-align: center;
}

.welcome-callout h3 {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 1rem;
}

.welcome-callout p {
    font-size: 1.05rem;
    color: var(--text-light);
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

.welcome-callout strong {
    color: var(--primary-color);
}

.welcome-callout .btn {
    margin-top: 0.5rem;
}

/* Dates Section */
.dates-section {
    padding: 100px 0;
    background: var(--bg-secondary);
    overflow-x: auto;
}

.timeline {
    position: relative;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    max-width: 1100px;
    margin: 0 auto;
    padding: 3rem 2rem;
    min-width: 800px;
}

.timeline::before {
    content: '';
    position: absolute;
    top: 85px;
    left: 2rem;
    right: 2rem;
    height: 4px;
    background: linear-gradient(90deg, #4facfe 0%, #667eea 50%, #764ba2 100%);
    border-radius: 2px;
}

.timeline-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
    flex: 1;
    text-align: center;
}

.timeline-date {
    margin-bottom: 1rem;
}

.timeline-date .month {
    display: block;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 2px;
}

.timeline-date .day {
    display: block;
    font-size: 2.5rem;
    font-weight: 800;
    line-height: 1;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.timeline-marker {
    width: 24px;
    height: 24px;
    background: var(--card-bg);
    border: 4px solid #667eea;
    border-radius: 50%;
    z-index: 2;
    margin-bottom: 1.5rem;
    transition: all 0.3s ease;
}

.timeline-marker.active {
    background: #4facfe;
    border-color: #4facfe;
    box-shadow: 0 0 20px rgba(79, 172, 254, 0.6);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        box-shadow: 0 0 20px rgba(79, 172, 254, 0.6);
    }
    50% {
        box-shadow: 0 0 30px rgba(79, 172, 254, 0.9);
    }
}

.timeline-item:hover .timeline-marker {
    transform: scale(1.3);
    border-color: #4facfe;
    box-shadow: 0 0 20px rgba(79, 172, 254, 0.5);
}

.timeline-content {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 16px;
    box-shadow: var(--shadow-soft);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    width: 100%;
    max-width: 220px;
}


.timeline-item:hover .timeline-content {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.timeline-icon {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
}

.timeline-content h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.timeline-content p {
    font-size: 0.85rem;
    color: var(--text-light);
    margin: 0;
    line-height: 1.4;
}

/* Speakers Section */
.speakers-section {
    padding: 100px 0;
    background: var(--card-bg);
}

.speakers-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

@media (max-width: 900px) {
    .speakers-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
}

.speaker-card {
    background: var(--card-bg);
    border-radius: 24px;
    overflow: hidden;
    box-shadow: var(--shadow-soft);
    transition: all 0.4s ease;
    text-align: center;
    border: 1px solid var(--border-color);
}

.speaker-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-hover);
}

.speaker-image {
    width: 100%;
    aspect-ratio: 1 / 1;
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.speaker-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center center;
    transition: transform 0.3s ease;
}

.speaker-card:hover .speaker-image img {
    transform: scale(1.05);
}

.placeholder-image {
    color: white;
    font-weight: 700;
    font-size: 2rem;
    opacity: 0.8;
}

.speaker-name {
    font-size: 1.25rem;
    font-weight: 700;
    margin: 1.25rem 1rem 0.5rem;
    color: var(--text-color);
}

.speaker-affiliation {
    font-size: 0.9rem;
    color: var(--primary-color);
    font-weight: 500;
    margin-bottom: 0.4rem;
    padding: 0 0.5rem;
}

.speaker-topic {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 1.5rem;
    padding: 0 0.5rem;
}

/* Track Sections */
.track-section {
    padding: 100px 0;
}

.track-section:nth-child(even) {
    background: var(--bg-secondary);
}

.track-header {
    text-align: center;
    margin-bottom: 4rem;
}

.track-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.track-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: start;
}

.track-info h3, .submission-info h3 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

.track-info ul {
    list-style: none;
    margin: 2rem 0;
}

.track-info li {
    padding: 0.8rem 0;
    padding-left: 2rem;
    position: relative;
    font-size: 1.1rem;
    color: var(--text-color);
}

.track-info li::before {
    content: "•";
    color: var(--primary-color);
    position: absolute;
    left: 0;
    font-size: 1.5rem;
    line-height: 1;
}

.guidelines-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin: 2rem 0;
    justify-content: center;
}

.guideline-item {
    background: var(--card-bg);
    padding: 0.6rem 1.2rem;
    border-radius: 50px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    font-size: 0.9rem;
    white-space: nowrap;
}

.guideline-item strong {
    color: var(--primary-color);
}

.guideline-item a,
.guideline-item a:visited {
    color: var(--primary-color);
    text-decoration: none;
}

.guideline-item a:hover {
    text-decoration: underline;
}

.acceptance-info {
    margin-top: 2rem;
    padding: 2rem;
    background: rgba(0, 122, 255, 0.05);
    border-radius: 16px;
    border: 1px solid rgba(0, 122, 255, 0.1);
}

.acceptance-info h4 {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.acceptance-info li {
    color: var(--text-color);
}

.btn-spacer {
    margin-top: 3rem;
    display: inline-block;
    width: 100%;
    text-align: center;
}

/* Competition Track */
.competition-track {
    background: var(--gradient-primary);
    color: white;
    position: relative;
    overflow: hidden;
}

.competition-track::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: radial-gradient(rgba(255, 255, 255, 0.1) 1px, transparent 1px);
    background-size: 30px 30px;
    opacity: 0.5;
}

.competition-track .section-title, 
.competition-track h3, 
.competition-track p, 
.competition-track li {
    color: white;
}

/* Challenge Hero - Main competition intro */
.challenge-hero {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 3rem;
    align-items: center;
    margin-bottom: 4rem;
    position: relative;
    z-index: 1;
}

.challenge-info h3 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #fff, rgba(255,255,255,0.8));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.challenge-tagline {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.85);
    margin-bottom: 2rem;
    line-height: 1.6;
}

.evaluation-highlights {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.eval-highlight {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    background: rgba(255, 255, 255, 0.1);
    padding: 0.75rem 1rem;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.15);
    font-size: 0.95rem;
}

.eval-icon {
    font-size: 1.2rem;
}

.eval-note {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.7);
    font-style: italic;
}

.try-dataset-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 1.5rem;
    padding: 0.75rem 1.25rem;
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: 50px;
    color: #fff;
    text-decoration: none;
    font-size: 0.95rem;
    transition: all 0.3s ease;
}

.try-dataset-link:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
}

.try-icon {
    font-size: 1.1rem;
}

.challenge-robot {
    text-align: center;
    background: rgba(255, 255, 255, 0.1);
    padding: 2rem;
    border-radius: 24px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    transition: transform 0.3s ease, background 0.3s ease;
}

.challenge-robot:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.15);
}

.challenge-robot .hsr-robot-img {
    max-width: 260px;
    height: auto;
    border-radius: 16px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.25);
}

.challenge-robot .robot-caption {
    margin-top: 1.25rem;
    font-size: 1rem;
    font-weight: 600;
    color: rgba(255, 255, 255, 0.95);
}

.comp-track-card {
    background: rgba(255, 255, 255, 0.08);
    padding: 2.5rem;
    border-radius: 24px;
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.15);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.comp-track-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    border-radius: 24px 24px 0 0;
}

.comp-track-card.simulation::before {
    background: linear-gradient(90deg, #4facfe, #00f2fe);
}

.comp-track-card.real-robot::before {
    background: linear-gradient(90deg, #f093fb, #f5576c);
}

.comp-track-card:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.12);
    border-color: rgba(255, 255, 255, 0.25);
}

.track-card-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.comp-track-card h4 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: white;
}

.comp-track-card > p {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

.comp-track-card ul {
    margin-top: 0;
}

.comp-track-card li {
    padding: 0.5rem 0;
    padding-left: 1.75rem;
    position: relative;
}

.comp-track-card li::before {
    content: "✓";
    position: absolute;
    left: 0;
}

.comp-track-card.simulation li::before {
    color: #4facfe;
}

.comp-track-card.real-robot li::before {
    color: #f5576c;
}

/* Competition Timeline */
.competition-timeline {
    grid-column: 1 / -1;
    margin: 2.5rem 0;
    text-align: center;
    position: relative;
    z-index: 1;
}

.competition-timeline h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: white;
}

.comp-timeline-container {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    padding: 0 1rem;
}

.comp-timeline-container::before {
    content: '';
    position: absolute;
    top: 20px;
    left: 10%;
    right: 10%;
    height: 3px;
    background: linear-gradient(90deg, rgba(255,255,255,0.3), rgba(255,255,255,0.5), rgba(255,255,255,0.3));
    border-radius: 2px;
}

.comp-timeline-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    flex: 1;
    position: relative;
}

.comp-timeline-date {
    background: rgba(255, 255, 255, 0.2);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: 700;
    font-size: 0.9rem;
    margin-bottom: 1rem;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.comp-timeline-content {
    text-align: center;
}

.comp-timeline-content strong {
    display: block;
    font-size: 1rem;
    margin-bottom: 0.25rem;
    color: white;
}

.comp-timeline-content span {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.7);
}

@media (max-width: 768px) {
    .comp-timeline-container {
        flex-direction: column;
        gap: 1.5rem;
        align-items: flex-start;
    }

    .comp-timeline-container::before {
        top: 0;
        bottom: 0;
        left: 20px;
        right: auto;
        width: 3px;
        height: auto;
    }

    .comp-timeline-item {
        flex-direction: row;
        gap: 1rem;
        padding-left: 40px;
    }

    .comp-timeline-content {
        text-align: left;
    }
}

.data-engine {
    grid-column: 1 / -1;
    margin-top: 2rem;
    margin-bottom: 2rem;
    text-align: center;
    position: relative;
    z-index: 1;
}

.data-engine h3 {
    font-size: 1.5rem;
    margin-bottom: 0.4rem;
}

.data-engine-subtitle {
    color: rgba(255, 255, 255, 0.7);
    font-size: 1rem;
    margin-bottom: 1.5rem;
}

.data-features {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    margin-top: 2rem;
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.data-feature {
    background: rgba(255, 255, 255, 0.08);
    padding: 1.75rem 2rem;
    border-radius: 16px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: white;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 1.5rem;
    text-align: left;
}

.data-feature:hover {
    transform: translateY(-3px);
    background: rgba(255, 255, 255, 0.12);
    border-color: rgba(255, 255, 255, 0.2);
}

.data-feature-icon {
    font-size: 2.25rem;
    flex-shrink: 0;
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 14px;
}

.data-feature-content {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.data-feature-content strong {
    font-size: 1.25rem;
    font-weight: 600;
}

.data-feature-content span {
    font-size: 1rem;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.5;
}

.data-feature-content a {
    color: #fff;
    text-decoration: underline;
    text-underline-offset: 2px;
}

.data-feature-content a:hover {
    color: rgba(255, 255, 255, 0.85);
}

.prizes {
    grid-column: 1 / -1;
    margin-top: 2rem;
    text-align: center;
}

.prizes h3 {
    margin-bottom: 1.5rem;
}

.prize-grid {
    display: flex;
    justify-content: center;
    align-items: flex-end;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.prize-item {
    background: rgba(255, 255, 255, 0.1);
    padding: 2rem 2.5rem;
    border-radius: 20px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: all 0.3s ease;
    text-align: center;
    min-width: 160px;
}

.prize-item:hover {
    transform: translateY(-5px);
}

.prize-item.gold {
    background: linear-gradient(135deg, rgba(255, 215, 0, 0.2), rgba(255, 180, 0, 0.1));
    border-color: rgba(255, 215, 0, 0.4);
    order: 2;
    padding: 2.5rem 3rem;
    min-width: 180px;
}

.prize-item.silver {
    background: linear-gradient(135deg, rgba(192, 192, 192, 0.2), rgba(169, 169, 169, 0.1));
    border-color: rgba(192, 192, 192, 0.4);
    order: 1;
}

.prize-item.bronze {
    background: linear-gradient(135deg, rgba(205, 127, 50, 0.2), rgba(180, 100, 40, 0.1));
    border-color: rgba(205, 127, 50, 0.4);
    order: 3;
}

.prize-medal {
    font-size: 3rem;
    margin-bottom: 0.75rem;
}

.prize-item.gold .prize-medal {
    font-size: 3.5rem;
}

.prize-place {
    font-size: 1rem;
    font-weight: 600;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.prize-amount {
    font-size: 1.75rem;
    font-weight: 700;
    color: #fff;
}

.prize-item.gold .prize-amount {
    font-size: 2rem;
    color: #ffd700;
}

.prize-item.silver .prize-amount {
    color: #e0e0e0;
}

.prize-item.bronze .prize-amount {
    color: #dda15e;
}

/* Program Section */
.program-section {
    padding: 100px 0;
    background: var(--card-bg);
}

.program-note {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.program-schedule {
    background: var(--bg-secondary);
    border-radius: 24px;
    overflow: hidden;
    box-shadow: var(--shadow-soft);
    border: 1px solid var(--border-color);
    max-width: 900px;
    margin: 0 auto;
}

.session-header {
    padding: 1.25rem 2rem;
    font-weight: 700;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    font-size: 0.95rem;
}

.session-header h3 {
    margin: 0;
    font-size: inherit;
}

.session-header.morning {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.session-header.afternoon {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: white;
}

.program-item {
    display: grid;
    grid-template-columns: 140px 1fr;
    gap: 1.5rem;
    padding: 1.25rem 2rem;
    border-bottom: 1px solid var(--border-color);
    align-items: center;
    transition: background 0.2s ease;
}

.program-item:last-child {
    border-bottom: none;
}

.program-item:hover {
    background: rgba(255, 255, 255, 0.03);
}

.program-item.break {
    background: rgba(0, 0, 0, 0.1);
}

.program-item.break:hover {
    background: rgba(0, 0, 0, 0.15);
}

.time {
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--primary-color);
    font-family: 'SF Mono', 'Monaco', 'Consolas', monospace;
}

.activity {
    color: var(--text-color);
}

.activity-title {
    font-weight: 600;
    font-size: 1.05rem;
    margin-bottom: 0.2rem;
}

.activity-speaker {
    font-size: 0.9rem;
    color: var(--text-light);
}

.program-item.panel .activity-title::before {
    content: "💬 ";
}

.program-item.competition .activity-title::before {
    content: "🏆 ";
}

.program-item.spotlight .activity-title::before {
    content: "⚡ ";
}

.program-item.break .activity-title {
    color: var(--text-light);
    font-weight: 500;
}

.program-item.break .activity-title::before {
    content: "☕ ";
}

/* Organizers Section */
.organizers-section {
    padding: 100px 0;
    background: var(--bg-secondary);
}

.organizer-note {
    text-align: center;
    margin-bottom: 2.5rem;
    color: var(--text-light);
}

.organizers-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
    max-width: 1100px;
    margin: 0 auto;
}

@media (max-width: 1000px) {
    .organizers-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 768px) {
    .organizers-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.organizer-card {
    background: var(--card-bg);
    border-radius: 16px;
    overflow: hidden;
    box-shadow: var(--shadow-soft);
    transition: all 0.3s ease;
    text-align: center;
    border: 1px solid var(--border-color);
    padding: 1.5rem 1rem;
}

.organizer-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.organizer-image {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    margin: 0 auto 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-accent);
    overflow: hidden;
}

.organizer-image .placeholder-image {
    color: white;
    font-weight: 700;
    font-size: 1.25rem;
}

.organizer-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.organizer-name {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
    color: var(--text-color);
}

.organizer-affiliation {
    font-size: 0.85rem;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.organizer-email {
    font-size: 0.75rem;
    color: var(--text-light);
    word-break: break-all;
}

.speaker-name a, .organizer-name a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s ease;
}

.speaker-name a:hover, .organizer-name a:hover {
    color: var(--primary-color);
}

body.dark-theme .speaker-name a, body.dark-theme .organizer-name a {
    color: var(--text-color);
}

body.dark-theme .speaker-name a:hover, body.dark-theme .organizer-name a:hover {
    color: #4facfe;
}


/* Footer */
.footer {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    color: white;
    padding: 80px 0 40px;
}

body.dark-theme .footer {
    background: linear-gradient(135deg, #0a0a15 0%, #0f1525 100%);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1.5fr;
    gap: 4rem;
    margin-bottom: 3rem;
}

.footer-info h3 {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.footer-info p {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
}

.footer-links h4,
.footer-contact h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1.25rem;
    color: white;
}

.footer-links ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: #4facfe;
}

.footer-contact p {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 2rem;
    text-align: center;
}

.footer-bottom p {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .footer-content {
        grid-template-columns: 1fr;
        gap: 2.5rem;
        text-align: center;
    }
}

/* Toast Notification */
#toast-container {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 9999;
}

.toast {
    background: rgba(30, 30, 30, 0.9);
    color: white;
    padding: 12px 24px;
    border-radius: 12px;
    margin-top: 10px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 500;
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

/* Scroll Animation */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease-out;
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .nav-container {
        height: 60px;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 60px;
        flex-direction: column;
        background-color: var(--card-bg);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        padding: 2rem 0;
        gap: 1rem;
        margin-right: 0;
        border-bottom: 1px solid var(--border-color);
        box-shadow: var(--shadow-soft);
    }
    
    .nav-menu.active {
        left: 0;
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        padding-top: 0;
    }

    .hero-title {
        font-size: 2.8rem;
    }
    
    .hero-buttons {
        justify-content: center;
        flex-direction: column;
    }
    
    .track-content {
        grid-template-columns: 1fr;
    }
    
    .challenge-hero {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .challenge-robot {
        order: -1;
        margin-bottom: 2rem;
    }

    .challenge-robot .hsr-robot-img {
        max-width: 200px;
    }

    .evaluation-highlights {
        grid-template-columns: 1fr;
    }

    .challenge-info h3 {
        font-size: 1.8rem;
    }

    /* Timeline Mobile - horizontal scroll */
    .dates-section {
        padding: 60px 0;
    }

    .timeline {
        min-width: 700px;
        padding: 2rem 1rem;
    }

    .timeline::before {
        top: 70px;
    }

    .timeline-date .day {
        font-size: 2rem;
    }

    .timeline-marker {
        width: 20px;
        height: 20px;
    }

    .timeline-content {
        padding: 1rem;
        max-width: 160px;
    }

    .timeline-content h3 {
        font-size: 0.9rem;
    }

    .timeline-content p {
        font-size: 0.8rem;
    }

    .data-features {
        grid-template-columns: 1fr;
    }

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

    .prize-item.gold,
    .prize-item.silver,
    .prize-item.bronze {
        order: unset;
        min-width: 200px;
    }

    .program-item {
        grid-template-columns: 1fr;
        text-align: left;
        gap: 0.5rem;
    }

    .time {
        font-size: 0.85rem;
    }

    .hamburger {
        display: flex;
    }
}

/* Robot Display Styling */
.robot-display {
    margin-top: 3rem;
    display: inline-block;
    background: rgba(255, 255, 255, 0.1);
    padding: 2rem;
    border-radius: 24px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    transition: transform 0.3s ease;
}

.robot-display:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.15);
}

.hsr-robot-img {
    max-height: 300px;
    width: auto;
    max-width: 100%;
    display: block;
    margin: 0 auto 1rem;
    border-radius: 12px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
}

.robot-caption {
    margin: 0 !important;
    font-weight: 600;
    font-size: 1.1rem;
    color: rgba(255, 255, 255, 0.95) !important;
}

@media (max-width: 768px) {
    .hsr-robot-img {
        max-height: 200px;
    }
}