/* ============================================
   bable.pro - Retro-Astronomical Observatory
   Geological Sci-Fi / Mountain Observatory
   ============================================ */

/* --- CSS Custom Properties --- */
:root {
    /* Palette - Geological Naming */
    --summit-fog: #f0eeeb;
    --cirrus: #c8c5c0;
    --granite: #8a8784;
    --basalt: #4d4a47;
    --obsidian: #1e1d1b;
    --marble-white: #faf9f7;
    --vein-blue: #7b9bae;
    --rust-signal: #b8704a;
    --chalk-white: #e8e4df;
    --graphite: #3a3a3c;

    /* Typography */
    --font-handwritten: 'Caveat', cursive;
    --font-body: 'IBM Plex Sans', sans-serif;
    --font-mono: 'IBM Plex Mono', monospace;

    /* Morph Timing */
    --morph-bezier: cubic-bezier(0.45, 0.05, 0.55, 0.95);

    /* Parallax Depths */
    --stratum-valley: translateZ(-300px) scale(2);
    --stratum-treeline: translateZ(-150px) scale(1.5);
    --stratum-observatory: translateZ(0px) scale(1);
    --stratum-summit: translateZ(100px) scale(0.8);
}

/* --- Reset & Base --- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    overflow-x: hidden;
}

body {
    font-family: var(--font-body);
    font-weight: 400;
    color: var(--basalt);
    background: var(--obsidian);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* --- Scroll Container --- */
#scroll-container {
    width: 100%;
    position: relative;
}

/* --- Strata Navigation --- */
#strata-nav {
    position: fixed;
    right: 24px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.nav-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    transition: all 0.4s var(--morph-bezier);
    background:
        repeating-linear-gradient(
            135deg,
            transparent 0px,
            rgba(123, 155, 174, 0.15) 1px,
            transparent 2px
        ),
        var(--granite);
    opacity: 0.6;
}

.nav-dot:hover {
    opacity: 0.9;
    transform: scale(1.3);
}

.nav-dot.active {
    background: var(--vein-blue);
    opacity: 1;
    box-shadow: 0 0 8px rgba(123, 155, 174, 0.4);
}

/* --- Stratum Base --- */
.stratum {
    width: 100%;
    min-height: 100vh;
    position: relative;
    overflow: hidden;
    display: grid;
    grid-template-columns: [margin-start] 1fr [content-start] minmax(320px, 800px) [content-end] 1fr [margin-end];
}

.stratum-content {
    grid-column: content-start / content-end;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 80px 20px;
    position: relative;
    z-index: 10;
    gap: 48px;
}

/* --- Marble Surface System --- */
.marble-surface {
    position: absolute;
    inset: 0;
    z-index: 1;
    background:
        repeating-linear-gradient(
            135deg,
            transparent 0px,
            rgba(123, 155, 174, 0.08) 2px,
            transparent 4px
        ),
        repeating-linear-gradient(
            45deg,
            transparent 0px,
            rgba(184, 112, 74, 0.05) 1px,
            transparent 3px
        ),
        radial-gradient(ellipse at 30% 50%, var(--summit-fog) 0%, var(--cirrus) 60%, var(--granite) 100%);
    filter: contrast(1.05) saturate(0.9);
    opacity: 0;
    transition: opacity 0.6s ease;
}

.valley-marble {
    background:
        repeating-linear-gradient(
            135deg,
            transparent 0px,
            rgba(123, 155, 174, 0.08) 2px,
            transparent 4px
        ),
        repeating-linear-gradient(
            45deg,
            transparent 0px,
            rgba(184, 112, 74, 0.05) 1px,
            transparent 3px
        ),
        radial-gradient(ellipse at 30% 50%, #2a2927 0%, #232220 60%, var(--obsidian) 100%);
}

.valley-marble.visible {
    opacity: 1;
}

.treeline-marble {
    background:
        repeating-linear-gradient(
            135deg,
            transparent 0px,
            rgba(123, 155, 174, 0.06) 2px,
            transparent 4px
        ),
        repeating-linear-gradient(
            45deg,
            transparent 0px,
            rgba(184, 112, 74, 0.04) 1px,
            transparent 3px
        ),
        radial-gradient(ellipse at 60% 40%, var(--chalk-white) 0%, var(--summit-fog) 50%, var(--cirrus) 100%);
    opacity: 1;
}

.observatory-marble {
    background:
        repeating-linear-gradient(
            135deg,
            transparent 0px,
            rgba(123, 155, 174, 0.07) 2px,
            transparent 4px
        ),
        repeating-linear-gradient(
            45deg,
            transparent 0px,
            rgba(184, 112, 74, 0.04) 1px,
            transparent 3px
        ),
        radial-gradient(ellipse at 40% 60%, var(--marble-white) 0%, var(--summit-fog) 50%, var(--cirrus) 100%);
    opacity: 1;
}

/* --- STRATUM 0: Valley --- */
#stratum-valley {
    background: var(--obsidian);
    min-height: 100vh;
}

/* Vein SVG Overlay */
#vein-svg {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    z-index: 2;
    pointer-events: none;
}

#vein-primary {
    animation: drawVeinPrimary 1200ms ease-in-out 400ms forwards;
}

#vein-branch-1 {
    animation: drawVeinBranch 800ms ease-in-out 1600ms forwards;
}

#vein-branch-2 {
    animation: drawVeinBranch2 600ms ease-in-out 2000ms forwards;
}

#vein-branch-3 {
    animation: drawVeinBranch3 500ms ease-in-out 2200ms forwards;
}

@keyframes drawVeinPrimary {
    to { stroke-dashoffset: 0; }
}

@keyframes drawVeinBranch {
    to { stroke-dashoffset: 0; }
}

@keyframes drawVeinBranch2 {
    to { stroke-dashoffset: 0; }
}

@keyframes drawVeinBranch3 {
    to { stroke-dashoffset: 0; }
}

/* Valley Content */
.valley-content {
    justify-content: center;
    align-items: center;
    text-align: center;
    min-height: 100vh;
}

.hero-title {
    font-family: var(--font-handwritten);
    font-weight: 700;
    font-size: clamp(3rem, 8vw, 7rem);
    color: var(--chalk-white);
    opacity: 0;
    animation: fadeInHero 800ms ease-out 2700ms forwards;
    letter-spacing: 0.02em;
    text-shadow: 0 2px 20px rgba(30, 29, 27, 0.5);
}

@keyframes fadeInHero {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero-subtitle {
    position: relative;
    height: 2em;
    display: flex;
    align-items: center;
    justify-content: center;
}

.subtitle-text {
    font-family: var(--font-body);
    font-weight: 300;
    font-size: clamp(1rem, 2vw, 1.4rem);
    color: var(--cirrus);
    letter-spacing: 0.3em;
    text-transform: uppercase;
    opacity: 0;
    animation: fadeInSubtitle 600ms ease-out 3500ms forwards;
    position: absolute;
}

.subtitle-text.hidden {
    opacity: 0 !important;
    pointer-events: none;
}

.subtitle-prob {
    font-family: var(--font-mono);
    font-weight: 400;
    font-size: clamp(0.9rem, 1.6vw, 1.2rem);
    color: var(--vein-blue);
    font-variant-numeric: tabular-nums;
    opacity: 0;
    position: absolute;
}

.subtitle-prob.visible {
    opacity: 1;
    transition: opacity 0.5s ease;
}

@keyframes fadeInSubtitle {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* --- Mountain Silhouettes --- */
.mountain-silhouette {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    z-index: 5;
    pointer-events: none;
}

.mountain-valley {
    height: 200px;
}

.mountain-path {
    stroke-dasharray: 3000;
    stroke-dashoffset: 3000;
    fill: var(--basalt);
    stroke: none;
    animation: drawMountain 2000ms ease-in-out 3000ms forwards;
}

@keyframes drawMountain {
    to {
        stroke-dashoffset: 0;
    }
}

.mountain-treeline-bg {
    height: 180px;
    z-index: 3;
    bottom: 0;
    animation: subtlePeakShift 20s var(--morph-bezier) infinite alternate;
}

.mountain-treeline-fg {
    height: 160px;
    z-index: 4;
    bottom: 0;
}

.mountain-summit {
    height: 100px;
    bottom: 0;
}

@keyframes subtlePeakShift {
    0% { transform: scaleY(1); }
    50% { transform: scaleY(1.03); }
    100% { transform: scaleY(0.98); }
}

/* --- Scroll Indicator --- */
.scroll-indicator {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 20;
    animation: pulseChevron 2s var(--morph-bezier) infinite;
    opacity: 0;
    animation: pulseChevron 2s var(--morph-bezier) infinite, fadeInChevron 0.5s ease-out 4500ms forwards;
}

@keyframes pulseChevron {
    0%, 100% { transform: translateX(-50%) scale(1); }
    50% { transform: translateX(-50%) scale(1.15); }
}

@keyframes fadeInChevron {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* --- Fog Layers --- */
.fog-layer {
    position: absolute;
    inset: 0;
    z-index: 6;
    pointer-events: none;
}

.fog-valley {
    background: linear-gradient(to top, rgba(30, 29, 27, 0.6) 0%, transparent 60%);
    mix-blend-mode: multiply;
    animation: fogDrift 30s ease-in-out infinite alternate;
    opacity: 0.5;
}

.fog-treeline {
    background: linear-gradient(to top, rgba(30, 29, 27, 0.3) 0%, transparent 40%);
    mix-blend-mode: multiply;
    animation: fogDrift 25s ease-in-out infinite alternate-reverse;
    opacity: 0.3;
}

.fog-observatory {
    background: linear-gradient(to bottom, rgba(200, 197, 192, 0.15) 0%, transparent 30%);
    mix-blend-mode: multiply;
    opacity: 0.2;
}

@keyframes fogDrift {
    0% { transform: translateX(-20px); }
    100% { transform: translateX(20px); }
}

/* Fog breathing animation */
.fog-valley {
    animation: fogDrift 30s ease-in-out infinite alternate, fogBreathe 15s var(--morph-bezier) infinite;
}

@keyframes fogBreathe {
    0%, 100% { opacity: 0.5; }
    50% { opacity: 0.35; }
}

/* --- Transition Zones --- */
.transition-zone {
    height: 200px;
    position: relative;
    z-index: 7;
}

.transition-01 {
    background: linear-gradient(to bottom, var(--obsidian) 0%, var(--summit-fog) 100%);
}

.transition-12 {
    background: linear-gradient(to bottom, var(--summit-fog) 0%, var(--marble-white) 100%);
}

.transition-23 {
    background: linear-gradient(to bottom, var(--marble-white) 0%, var(--summit-fog) 100%);
}

/* --- STRATUM 1: Treeline --- */
#stratum-treeline {
    background: var(--summit-fog);
}

/* --- STRATUM 2: Observatory --- */
#stratum-observatory {
    background: var(--marble-white);
    min-height: 200vh;
}

.observatory-content {
    gap: 64px;
    padding: 120px 20px;
}

/* --- STRATUM 3: Summit --- */
#stratum-summit {
    background: var(--summit-fog);
    min-height: 100vh;
}

.summit-background {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse at 50% 50%, var(--summit-fog) 0%, var(--cirrus) 70%);
    z-index: 1;
}

.summit-content {
    min-height: 100vh;
    justify-content: center;
    align-items: center;
}

.summit-equation {
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.summit-formula {
    font-family: var(--font-handwritten);
    font-weight: 700;
    font-size: clamp(2.5rem, 6vw, 5rem);
    color: var(--basalt);
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 1s ease, transform 1s ease;
}

.summit-formula.visible {
    opacity: 1;
    transform: translateY(0);
}

.summit-annotation {
    font-family: var(--font-handwritten);
    font-weight: 700;
    font-size: clamp(1rem, 2vw, 1.4rem);
    color: var(--granite);
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 1.2s ease 0.3s, transform 1.2s ease 0.3s;
}

.summit-annotation.visible {
    opacity: 0.7;
    transform: translateY(0);
}

/* --- Section Epigraphs --- */
.section-epigraph {
    font-family: var(--font-handwritten);
    font-weight: 700;
    font-size: clamp(1.2rem, 2.5vw, 1.8rem);
    color: var(--rust-signal);
    text-align: center;
    max-width: 600px;
    line-height: 1.5;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.section-epigraph.visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- Marble Panels --- */
.marble-panel {
    background:
        repeating-linear-gradient(
            135deg,
            transparent 0px,
            rgba(123, 155, 174, 0.06) 2px,
            transparent 4px
        ),
        repeating-linear-gradient(
            45deg,
            transparent 0px,
            rgba(184, 112, 74, 0.03) 1px,
            transparent 3px
        ),
        radial-gradient(ellipse at 40% 30%, var(--marble-white) 0%, var(--summit-fog) 80%);
    border: 1px solid var(--cirrus);
    padding: 48px 40px;
    width: 100%;
    max-width: 720px;
    position: relative;
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease, filter 0.3s ease;
    animation: morphPanel 12s var(--morph-bezier) infinite;
    border-radius: 20% 60% 40% 80% / 60% 30% 70% 40%;
}

.marble-panel.visible {
    opacity: 1;
    transform: translateY(0);
}

.marble-panel:hover {
    filter: contrast(1.1);
}

.marble-panel:hover .marble-surface-overlay {
    opacity: 0.12;
}

@keyframes morphPanel {
    0% { border-radius: 20% 60% 40% 80% / 60% 30% 70% 40%; }
    33% { border-radius: 50% 30% 60% 40% / 40% 60% 30% 70%; }
    66% { border-radius: 30% 50% 70% 20% / 50% 40% 60% 50%; }
    100% { border-radius: 20% 60% 40% 80% / 60% 30% 70% 40%; }
}

.panel-heading {
    font-family: var(--font-handwritten);
    font-weight: 700;
    font-size: clamp(1.5rem, 3vw, 2.2rem);
    color: var(--graphite);
    margin-bottom: 24px;
}

.panel-body {
    font-family: var(--font-body);
    font-weight: 400;
    font-size: clamp(0.95rem, 1.8vw, 1.15rem);
    line-height: 1.75;
    letter-spacing: 0.01em;
    color: var(--basalt);
    margin-bottom: 16px;
}

.panel-body:last-of-type {
    margin-bottom: 24px;
}

.panel-formula {
    display: block;
    font-family: var(--font-mono);
    font-weight: 400;
    font-size: clamp(0.8rem, 1.4vw, 1rem);
    font-variant-numeric: tabular-nums;
    color: var(--vein-blue);
    margin-top: 16px;
    padding: 12px 16px;
    background: rgba(30, 29, 27, 0.04);
    border-left: 2px solid var(--vein-blue);
}

/* --- Handwritten Marginalia --- */
.marginalia {
    position: absolute;
    font-family: var(--font-handwritten);
    font-weight: 700;
    font-size: clamp(0.85rem, 1.5vw, 1.1rem);
    color: var(--rust-signal);
    opacity: 0;
    transition: opacity 0.8s ease;
    z-index: 15;
    pointer-events: none;
    white-space: nowrap;
}

.marginalia.visible {
    opacity: 0.6;
}

.margin-left {
    left: 20px;
    grid-column: margin-start / content-start;
}

.margin-right {
    right: 20px;
    grid-column: content-end / margin-end;
    text-align: right;
}

/* --- Probability Dial --- */
.probability-dial-container {
    display: flex;
    justify-content: center;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.probability-dial-container.visible {
    opacity: 1;
    transform: translateY(0);
}

.probability-dial {
    width: 200px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

#dial-svg {
    width: 200px;
    height: 200px;
}

#dial-needle {
    transform-origin: 100px 100px;
    animation: dialOscillate 8s var(--morph-bezier) infinite;
}

@keyframes dialOscillate {
    0%, 100% { transform: rotate(-3deg); }
    50% { transform: rotate(3deg); }
}

.dial-reading {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.dial-label {
    font-family: var(--font-body);
    font-weight: 300;
    font-size: 0.75rem;
    color: var(--granite);
    text-transform: uppercase;
    letter-spacing: 0.15em;
}

.dial-value {
    font-family: var(--font-mono);
    font-weight: 400;
    font-size: 1.1rem;
    font-variant-numeric: tabular-nums;
    color: var(--vein-blue);
}

/* --- Probability Bars --- */
.prob-bars {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-top: 24px;
    width: 100%;
}

.prob-bar-row {
    display: flex;
    align-items: center;
    gap: 16px;
}

.prob-bar-label {
    font-family: var(--font-body);
    font-weight: 300;
    font-size: 0.85rem;
    color: var(--granite);
    min-width: 140px;
    text-align: right;
}

.prob-bar-track {
    flex: 1;
    height: 6px;
    background: rgba(200, 197, 192, 0.4);
    border-radius: 3px;
    position: relative;
    overflow: hidden;
}

.prob-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--vein-blue), var(--vein-blue));
    border-radius: 3px;
    width: 0%;
    transition: width 1.5s var(--morph-bezier);
    position: relative;
}

.prob-bar-fill.filled {
    /* width set by JS */
}

.prob-bar-value {
    position: absolute;
    right: -40px;
    top: -8px;
    font-family: var(--font-mono);
    font-weight: 400;
    font-size: 0.7rem;
    font-variant-numeric: tabular-nums;
    color: var(--vein-blue);
    white-space: nowrap;
}

/* --- Bell Curve --- */
.bell-curve-svg {
    width: 100%;
    max-width: 400px;
    margin: 0 auto;
    display: block;
    grid-column: content-start / content-end;
    position: relative;
    z-index: 10;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.bell-curve-svg.visible {
    opacity: 1;
    transform: translateY(0);
}

#bell-curve-path.drawn {
    animation: drawBellCurve 2s ease-in-out forwards;
}

@keyframes drawBellCurve {
    to { stroke-dashoffset: 0; }
}

/* --- Scroll Reveal Utility --- */
.scroll-reveal {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.scroll-reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- Staggered Paragraph Reveals --- */
.marble-panel .panel-body:nth-child(2) {
    transition-delay: 0s;
}

.marble-panel .panel-body:nth-child(3) {
    transition-delay: 0.2s;
}

.marble-panel .panel-body:nth-child(4) {
    transition-delay: 0.4s;
}

.marble-panel.visible .panel-body {
    opacity: 1;
}

/* --- Responsive --- */
@media (max-width: 768px) {
    #strata-nav {
        right: 12px;
    }

    .nav-dot {
        width: 6px;
        height: 6px;
    }

    .marble-panel {
        padding: 32px 24px;
        border-radius: 12px;
        animation: none;
    }

    .marginalia {
        display: none;
    }

    .prob-bar-label {
        min-width: 100px;
        font-size: 0.75rem;
    }

    .stratum-content {
        padding: 60px 16px;
    }

    .observatory-content {
        padding: 80px 16px;
    }
}

@media (max-width: 480px) {
    .marble-panel {
        padding: 24px 16px;
    }

    .prob-bar-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 6px;
    }

    .prob-bar-label {
        text-align: left;
        min-width: auto;
    }

    .prob-bar-value {
        right: 4px;
        top: -7px;
    }
}