/* continua.st - Parallax Storytelling Journey */
/* Palette: #0b1628, #3b82f6, #60a5fa, #e2e8f0, #94a3b8, #f59e0b, #1e293b */

:root {
    --bg: #0b1628;
    --bg-light: #1e293b;
    --spine: #3b82f6;
    --active: #60a5fa;
    --text: #e2e8f0;
    --text-sec: #94a3b8;
    --amber: #f59e0b;
    --card: #1e293b;
    --spine-border: rgba(59, 130, 246, 0.3);
    --spine-glow: rgba(96, 165, 250, 0.4);
}

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

html {
    scroll-behavior: smooth;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: 'Inter', sans-serif;
    font-weight: 400;
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Background Grid Overlay */
.bg-grid {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    background-image:
        repeating-linear-gradient(
            0deg,
            rgba(59, 130, 246, 0.025) 0px,
            transparent 1px,
            transparent 60px
        ),
        repeating-linear-gradient(
            90deg,
            rgba(59, 130, 246, 0.025) 0px,
            transparent 1px,
            transparent 60px
        );
}

/* ============================
   TIMELINE SPINE
   ============================ */
.timeline-spine {
    position: fixed;
    left: 50%;
    top: 0;
    width: 2px;
    height: 0%;
    background: var(--spine);
    z-index: 5;
    transform: translateX(-50%);
    pointer-events: none;
}

.spine-glow {
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 8px;
    height: 40px;
    background: linear-gradient(to top, var(--spine-glow), transparent);
    border-radius: 4px;
    filter: blur(4px);
    opacity: 0.8;
}

/* ============================
   HERO SECTION
   ============================ */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    z-index: 10;
    padding: 2rem;
}

.hero-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0;
}

.brand {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 600;
    font-size: clamp(3rem, 8vw, 5rem);
    color: var(--text);
    letter-spacing: -0.02em;
    line-height: 1.1;
}

.brand-dot {
    color: var(--spine);
}

.brand-tagline {
    font-family: 'Inter', sans-serif;
    font-weight: 300;
    font-size: clamp(0.9rem, 2vw, 1.1rem);
    color: var(--text-sec);
    margin-top: 0.75rem;
    letter-spacing: 0.05em;
}

.hero-divider {
    width: 40px;
    height: 1px;
    background: var(--spine);
    margin: 2rem 0;
    opacity: 0.5;
}

.hero-subtitle {
    font-family: 'Fira Code', monospace;
    font-size: 0.7rem;
    color: var(--text-sec);
    letter-spacing: 0.15em;
    text-transform: uppercase;
    opacity: 0.5;
}

.scroll-indicator {
    margin-top: 1.5rem;
    color: var(--text-sec);
    opacity: 0.4;
    animation: scrollBounce 2s ease-in-out infinite;
}

@keyframes scrollBounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(8px); }
}

/* ============================
   CHAPTER MARKERS
   ============================ */
.chapter-marker {
    text-align: center;
    padding: 4rem 0 2rem;
    position: relative;
    z-index: 10;
}

.chapter-numeral {
    display: block;
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 700;
    font-size: clamp(2rem, 5vw, 3.5rem);
    color: var(--amber);
    line-height: 1;
    text-shadow: 0 0 30px rgba(245, 158, 11, 0.3);
    transition: text-shadow 0.6s ease;
}

.chapter-marker.visible .chapter-numeral {
    text-shadow: 0 0 50px rgba(245, 158, 11, 0.5), 0 0 100px rgba(245, 158, 11, 0.15);
}

.chapter-title {
    display: block;
    font-family: 'Fira Code', monospace;
    font-size: 0.65rem;
    color: var(--text-sec);
    letter-spacing: 0.15em;
    text-transform: uppercase;
    margin-top: 0.75rem;
    opacity: 0.6;
}

/* ============================
   TIMELINE NODES
   ============================ */
.timeline-node {
    position: relative;
    z-index: 10;
    display: flex;
    align-items: flex-start;
    padding: 1.5rem 0;
    max-width: 960px;
    margin: 0 auto;
}

.node-right {
    padding-right: 2rem;
    padding-left: calc(50% + 50px);
    flex-direction: row;
}

.node-left {
    padding-left: 2rem;
    padding-right: calc(50% + 50px);
    flex-direction: row-reverse;
}

.node-center {
    justify-content: center;
    padding: 2rem;
}

/* Node Dot (on the spine) */
.node-dot {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    border: 2px solid var(--spine);
    background: var(--bg);
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    top: 2rem;
    z-index: 12;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.node-dot.active {
    background: var(--active);
    border-color: var(--active);
    box-shadow: 0 0 16px var(--spine-glow), 0 0 40px rgba(96, 165, 250, 0.15);
}

/* Pulse animation for dot activation */
@keyframes dotPulse {
    0% { box-shadow: 0 0 0 0 var(--spine-glow); }
    70% { box-shadow: 0 0 0 12px transparent; }
    100% { box-shadow: 0 0 0 0 transparent; }
}

.node-dot.pulse {
    animation: dotPulse 0.8s ease-out;
}

/* Node Connector (horizontal line from spine to panel) */
.node-connector {
    position: absolute;
    top: calc(2rem + 6px);
    height: 1px;
    background: var(--spine-border);
    width: 40px;
    transition: background 0.4s ease;
}

.node-right .node-connector {
    left: calc(50% + 7px);
}

.node-left .node-connector {
    right: calc(50% + 7px);
}

.timeline-node.visible .node-connector {
    background: var(--spine);
}

/* Small arrow on connector */
.node-right .node-connector::after {
    content: '';
    position: absolute;
    right: 0;
    top: -3px;
    width: 0;
    height: 0;
    border-left: 5px solid var(--spine-border);
    border-top: 3px solid transparent;
    border-bottom: 3px solid transparent;
    transition: border-color 0.4s ease;
}

.node-left .node-connector::after {
    content: '';
    position: absolute;
    left: 0;
    top: -3px;
    width: 0;
    height: 0;
    border-right: 5px solid var(--spine-border);
    border-top: 3px solid transparent;
    border-bottom: 3px solid transparent;
    transition: border-color 0.4s ease;
}

.timeline-node.visible .node-right .node-connector::after,
.timeline-node.visible.node-right .node-connector::after {
    border-left-color: var(--spine);
}

.timeline-node.visible .node-left .node-connector::after,
.timeline-node.visible.node-left .node-connector::after {
    border-right-color: var(--spine);
}

/* Node Panel (content card) */
.node-panel {
    background: var(--card);
    border: 1px solid var(--spine-border);
    border-radius: 4px;
    padding: 28px;
    max-width: 420px;
    width: 100%;
    transition: border-color 0.5s ease, box-shadow 0.5s ease;
}

.timeline-node.visible .node-panel {
    border-color: rgba(59, 130, 246, 0.5);
    box-shadow: 0 4px 30px rgba(11, 22, 40, 0.6), 0 0 1px rgba(59, 130, 246, 0.2);
}

.node-label {
    font-family: 'Fira Code', monospace;
    font-size: 0.6rem;
    font-weight: 500;
    color: var(--text-sec);
    letter-spacing: 0.15em;
    text-transform: uppercase;
    display: block;
    margin-bottom: 0.75rem;
}

.node-title {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 600;
    font-size: 1.25rem;
    color: var(--text);
    margin-bottom: 0.75rem;
    line-height: 1.3;
}

.node-text {
    font-size: 0.88rem;
    color: var(--text-sec);
    line-height: 1.7;
}

/* Mathematical formula blocks */
.node-formula {
    margin-top: 1rem;
    padding: 0.75rem 1rem;
    background: rgba(59, 130, 246, 0.06);
    border-left: 2px solid var(--spine-border);
    border-radius: 0 3px 3px 0;
}

.formula-text {
    font-family: 'Fira Code', monospace;
    font-size: 0.78rem;
    color: var(--active);
    letter-spacing: 0.03em;
}

.math-inline {
    font-family: 'Fira Code', monospace;
    color: var(--active);
    font-size: 0.85em;
}

/* Synthesis panel special styling */
.synthesis-panel {
    border-color: rgba(245, 158, 11, 0.3);
    background: linear-gradient(135deg, var(--card), rgba(30, 41, 59, 0.8));
}

.timeline-node.visible .synthesis-panel {
    border-color: rgba(245, 158, 11, 0.5);
    box-shadow: 0 4px 30px rgba(11, 22, 40, 0.6), 0 0 1px rgba(245, 158, 11, 0.2);
}

/* Dotted connections between related concepts */
.dotted-connection {
    width: 1px;
    height: 30px;
    margin: 0 auto;
    border-left: 1px dashed rgba(59, 130, 246, 0.15);
    position: relative;
    z-index: 6;
}

/* Final section */
.final-panel {
    background: transparent;
    border: none;
    text-align: center;
    max-width: 320px;
}

.timeline-node.visible .final-panel {
    border-color: transparent;
    box-shadow: none;
}

.final-text {
    font-family: 'Fira Code', monospace;
    font-size: 0.85rem;
    color: var(--text-sec);
    letter-spacing: 0.05em;
}

.final-subtext {
    font-family: 'Inter', sans-serif;
    font-size: 0.75rem;
    color: var(--text-sec);
    opacity: 0.4;
    margin-top: 0.5rem;
}

.footer-space {
    height: 20vh;
}

/* ============================
   FADE-IN ANIMATIONS
   ============================ */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.7s cubic-bezier(0.4, 0, 0.2, 1), transform 0.7s cubic-bezier(0.4, 0, 0.2, 1);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Staggered delays for hero elements */
.hero .fade-in:nth-child(1) { transition-delay: 0.2s; }
.hero .fade-in:nth-child(2) { transition-delay: 0.5s; }
.hero .fade-in:nth-child(3) { transition-delay: 0.8s; }
.hero .fade-in:nth-child(4) { transition-delay: 1.0s; }
.hero .fade-in:nth-child(5) { transition-delay: 1.2s; }

/* Node entry animations - staggered per side */
.node-right .node-panel {
    transform: translateX(20px);
    opacity: 0;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.6s ease;
}

.node-left .node-panel {
    transform: translateX(-20px);
    opacity: 0;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.6s ease;
}

.node-right.visible .node-panel,
.node-left.visible .node-panel {
    transform: translateX(0);
    opacity: 1;
}

/* ============================
   RESPONSIVE
   ============================ */
@media (max-width: 768px) {
    .timeline-spine {
        left: 24px;
    }

    .node-right,
    .node-left {
        padding-left: 56px;
        padding-right: 1.5rem;
        flex-direction: row;
    }

    .node-dot {
        left: 24px;
        transform: translateX(-50%);
    }

    .node-connector {
        left: 31px;
        width: 18px;
    }

    .node-right .node-connector,
    .node-left .node-connector {
        left: 31px;
        right: auto;
    }

    .node-right .node-connector::after {
        content: '';
        right: 0;
        left: auto;
        border-left: 5px solid var(--spine-border);
        border-right: none;
    }

    .node-left .node-connector::after {
        content: '';
        right: 0;
        left: auto;
        border-right: none;
        border-left: 5px solid var(--spine-border);
    }

    .node-right .node-panel,
    .node-left .node-panel {
        transform: translateX(10px);
    }

    .node-right.visible .node-panel,
    .node-left.visible .node-panel {
        transform: translateX(0);
    }

    .node-center {
        padding-left: 56px;
    }

    .chapter-marker {
        text-align: left;
        padding-left: 56px;
    }

    .brand {
        font-size: clamp(2.2rem, 8vw, 3.5rem);
    }
}

@media (max-width: 480px) {
    .node-panel {
        padding: 20px;
    }

    .node-title {
        font-size: 1.1rem;
    }

    .node-text {
        font-size: 0.82rem;
    }

    .chapter-numeral {
        font-size: clamp(1.8rem, 5vw, 2.5rem);
    }
}