:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --error-color: #ef4444;
    --bg-color: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-color: #f1f5f9;
    --text-secondary: #cbd5e1;
    --border-color: #475569;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--bg-color) 0%, #1e1b4b 100%);
    color: var(--text-color);
    min-height: 100vh;
    line-height: 1.6;
}

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

header {
    background: rgba(30, 41, 59, 0.8);
    backdrop-filter: blur(10px);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.8rem;
    font-weight: bold;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.language-switcher {
    display: flex;
    gap: 0.5rem;
}

.lang-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.9rem;
}

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

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

.hero {
    text-align: center;
    padding: 4rem 0 3rem;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #fff, var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    color: var(--text-secondary);
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto;
}

.section {
    margin: 3rem 0;
}

.section-title {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.section-title::before {
    content: '';
    width: 4px;
    height: 2rem;
    background: linear-gradient(180deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

.quiz-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

.quiz-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.quiz-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.quiz-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary-color);
    box-shadow: 0 8px 24px rgba(99, 102, 241, 0.2);
}

.quiz-card:hover::before {
    transform: scaleX(1);
}

.quiz-card h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.quiz-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.featured-badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    font-size: 0.75rem;
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.category-section {
    margin-top: 2rem;
}

.category-title {
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
    color: var(--primary-color);
}

.category-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.category-card {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: 16px;
    padding: 2rem;
    text-align: center;
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.category-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-color);
    box-shadow: 0 12px 32px rgba(99, 102, 241, 0.3);
}

.category-card:hover::before {
    transform: scaleX(1);
}

.category-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    filter: grayscale(0.3);
    transition: all 0.3s ease;
}

.category-card:hover .category-icon {
    filter: grayscale(0);
    transform: scale(1.1);
}

.category-card h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.category-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.quiz-container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    min-height: calc(100vh - 10rem);
}

.quiz-header {
    text-align: center;
    margin-bottom: 2rem;
}

.quiz-title {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.quiz-description {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.progress-bar {
    background: var(--bg-secondary);
    height: 8px;
    border-radius: 4px;
    margin: 1.5rem 0;
    overflow: hidden;
}

.progress-fill {
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    height: 100%;
    transition: width 0.5s ease;
    border-radius: 4px;
}

.quiz-input-section {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    margin-bottom: 2rem;
    text-align: center;
}

.quiz-input {
    width: 100%;
    max-width: 500px;
    padding: 1rem 1.5rem;
    font-size: 1.1rem;
    background: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-color);
    transition: all 0.3s ease;
}

.quiz-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.quiz-list {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 1rem;
    flex: 1;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 0.5rem;
    align-content: start;
    overflow-y: auto;
    max-height: calc(100vh - 350px);
}

/* Multi-column layouts based on item count */
.quiz-list.cols-2 {
    grid-template-columns: repeat(2, 1fr);
    max-height: calc(100vh - 320px);
}

.quiz-list.cols-3 {
    grid-template-columns: repeat(3, 1fr);
    max-height: calc(100vh - 320px);
}

.quiz-item {
    display: flex;
    align-items: center;
    padding: 0.5rem 0.8rem;
    background: var(--bg-tertiary);
    border-radius: 6px;
    transition: all 0.3s ease;
    min-height: 40px;
}

.quiz-item.revealed {
    background: linear-gradient(90deg, rgba(99, 102, 241, 0.1), rgba(139, 92, 246, 0.1));
    border: 1px solid var(--primary-color);
}

.quiz-item.revealed.correct-answer {
    animation: revealAnimation 0.5s ease;
}

@keyframes revealAnimation {
    0% { transform: scale(0.95); opacity: 0; }
    50% { transform: scale(1.02); }
    100% { transform: scale(1); opacity: 1; }
}

.item-position {
    font-size: 1.2rem;
    font-weight: bold;
    color: var(--primary-color);
    min-width: 40px;
}

.item-content {
    flex: 1;
}

.item-name {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.item-fact {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.item-placeholder {
    color: var(--text-secondary);
    font-style: italic;
}

.completion-message {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    margin-top: 2rem;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
}

.btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-color);
}

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

.mobile-message {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--success-color);
    color: white;
    padding: 1rem 2rem;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    box-shadow: 0 8px 24px rgba(16, 185, 129, 0.4);
    z-index: 1000;
    animation: slideUp 0.3s ease, fadeOut 0.3s ease 2.7s;
    opacity: 0;
    pointer-events: none;
}

.mobile-message.show {
    opacity: 1;
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        transform: translateX(-50%) translateY(100px);
        opacity: 0;
    }
    to {
        transform: translateX(-50%) translateY(0);
        opacity: 1;
    }
}

@keyframes fadeOut {
    to {
        opacity: 0;
        transform: translateX(-50%) translateY(20px);
    }
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .quiz-grid {
        grid-template-columns: 1fr;
    }
    
    .quiz-title {
        font-size: 1.8rem;
    }
    
    .quiz-list {
        max-height: calc(100vh - 380px);
        grid-template-columns: 1fr !important; /* Single column on mobile */
    }
    
    .quiz-item {
        padding: 0.6rem;
        font-size: 0.9rem;
    }
    
    .item-position {
        font-size: 1rem !important;
        min-width: 35px !important;
    }
    
    .item-name {
        font-size: 1rem !important;
    }
    
    .item-fact {
        font-size: 0.8rem !important;
    }
}


/* Footer */
.site-footer {
  margin-top: 3rem;
  border-top: 1px solid var(--border-color);
  background: var(--bg-secondary);
}
.site-footer .footer-grid {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 1rem;
  padding: 1.5rem 0;
  align-items: center;
}
.site-footer .footer-nav a {
  margin-right: 1rem;
  text-decoration: none;
  color: var(--text-secondary);
}
.site-footer .footer-nav a:hover {
  text-decoration: underline;
}
.site-footer .footer-copy {
  padding: 0.75rem 0 1.5rem;
  color: var(--text-secondary);
  font-size: 0.875rem;
  display: flex;
  justify-content: space-between;
}
.static-page {
  padding: 2rem 0;
}