@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Space+Grotesk:wght@400;500;600;700&display=swap');

body {
    font-family: 'Inter', sans-serif;
    background-color: #0f172a;
    color: #e2e8f0;
    line-height: 1.6;
}

h1,
h2,
h3,
h4 {
    font-family: 'Space Grotesk', sans-serif;
}

.timeline-container {
    position: relative;
}

.timeline-line {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 24px;
    width: 4px;
    background: linear-gradient(to bottom, #6366f1, #8b5cf6, #ec4899, #f43f5e);
    border-radius: 2px;
    z-index: 1;
}

.timeline-event {
    position: relative;
    z-index: 2;
    transition: transform 0.3s ease;
    padding-left: 52px;
}

.timeline-event:hover {
    transform: translateX(5px);
}

.timeline-dot {
    position: absolute;
    left: 0;
    top: 24px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: 3px solid #0f172a;
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 3;
}

.timeline-dot:hover {
    transform: scale(1.2);
}

.timeline-card {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s ease, opacity 0.5s ease, transform 0.5s ease;
    opacity: 0;
    transform: translateY(-20px);
}

.timeline-card.active {
    max-height: 800px;
    opacity: 1;
    transform: translateY(0);
}

.category-filter {
    transition: all 0.3s ease;
}

.category-filter:hover {
    transform: translateY(-2px);
}

.category-filter.active {
    color: white;
}

.era-label {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: bold;
}

.scroll-button {
    transition: all 0.3s ease;
}

.scroll-button:hover {
    transform: scale(1.05);
}

.concept {
    --cat-color: #6366f1;
    --cat-light: #e0e7ff;
    --cat-dark: #4338ca;
}

.system {
    --cat-color: #10b981;
    --cat-light: #d1fae5;
    --cat-dark: #047857;
}

.breakthrough {
    --cat-color: #f43f5e;
    --cat-light: #ffe4e6;
    --cat-dark: #be123c;
}

.cat-concept .timeline-dot {
    background-color: var(--cat-color);
    box-shadow: 0 0 10px rgba(99, 102, 241, 0.6);
}

.cat-system .timeline-dot {
    background-color: var(--cat-color);
    box-shadow: 0 0 10px rgba(16, 185, 129, 0.6);
}

.cat-breakthrough .timeline-dot {
    background-color: var(--cat-color);
    box-shadow: 0 0 10px rgba(244, 63, 94, 0.6);
}

.cat-concept .timeline-card {
    border-left: 4px solid var(--cat-color);
}

.cat-system .timeline-card {
    border-left: 4px solid var(--cat-color);
}

.cat-breakthrough .timeline-card {
    border-left: 4px solid var(--cat-color);
}

.year-marker {
    position: absolute;
    left: 24px;
    transform: translateX(-50%);
    padding: 4px 12px;
    border-radius: 16px;
    font-weight: 600;
    font-size: 0.875rem;
    color: white;
    z-index: 4;
}

.glow {
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.3);
}

@media (max-width: 640px) {
    .timeline-line {
        left: 20px;
    }

    .timeline-event {
        padding-left: 40px;
    }

    .timeline-dot {
        left: -4px;
        width: 20px;
        height: 20px;
    }

    .year-marker {
        left: 20px;
        font-size: 0.75rem;
        padding: 3px 8px;
    }
}