/* ============================================
   alth.ing -- Geological Rift Design System
   Thingvellir-inspired editorial descent
   ============================================ */

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

html {
    scroll-behavior: smooth;
}

:root {
    /* Palette: Thingvellir geology */
    --obsidian: #1c1a17;
    --lichen: #d4cfc5;
    --iron-gall: #8a6e42;
    --basalt: #5c564b;
    --peat: #2e2a24;
    --mist: #9ba8a3;
    --vellum-gold: #c9a85c;
    --body-on-light: #3a3632;
    --body-on-dark: #c4bdb0;
    --hairline: #7a7266;

    /* Typography */
    --font-display: "Cormorant Garamond", "IBM Plex Serif", "Source Serif 4", Georgia, serif;
    --font-body: "Source Serif 4", "IBM Plex Serif", Georgia, serif;
    --font-mark: "IBM Plex Sans", "Inter", system-ui, sans-serif;

    /* Easing & durations */
    --ease-geological: cubic-bezier(0.25, 0.1, 0.25, 1.0);
}

body {
    background-color: var(--lichen);
    color: var(--body-on-light);
    font-family: var(--font-body);
    font-weight: 400;
    font-size: clamp(1rem, 1.2vw, 1.15rem);
    line-height: 1.75;
    overflow-x: hidden;
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   Right-edge scroll progress (tectonic line)
   ============================================ */
.scroll-progress {
    position: fixed;
    top: 0;
    right: 0;
    width: 2px;
    height: 100vh;
    background-color: rgba(122, 114, 102, 0.18);
    z-index: 100;
    pointer-events: none;
}

.scroll-progress-fill {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 0%;
    background-color: var(--iron-gall);
    transition: height 120ms linear;
}

/* ============================================
   Scenes -- shared structure
   ============================================ */
.scene {
    position: relative;
    width: 100%;
    padding: 0;
}

/* ============================================
   Scene 1: The Rift (opening)
   ============================================ */
.scene-rift {
    height: 100vh;
    min-height: 640px;
    overflow: hidden;
}

.rift-upper,
.rift-lower {
    position: absolute;
    left: 0;
    width: 100%;
    height: 50%;
    will-change: transform;
}

.rift-upper {
    top: 0;
    background-color: var(--lichen);
    transform: translateX(0);
    animation: tectonic-drift-upper 30000ms var(--ease-geological) infinite alternate;
}

.rift-lower {
    bottom: 0;
    background-color: var(--lichen);
    clip-path: inset(100% 0 0 0);
    transform: translateX(0);
    animation: rift-lower-reveal 600ms var(--ease-geological) 2300ms forwards,
               tectonic-drift-lower 30000ms var(--ease-geological) 3000ms infinite alternate;
}

@keyframes rift-lower-reveal {
    from {
        clip-path: inset(100% 0 0 0);
        background-color: var(--lichen);
    }
    to {
        clip-path: inset(0 0 0 0);
        background-color: var(--obsidian);
    }
}

@keyframes tectonic-drift-upper {
    from { transform: translateX(0); }
    to   { transform: translateX(-0.5px); }
}

@keyframes tectonic-drift-lower {
    from { transform: translateX(0); }
    to   { transform: translateX(0.5px); }
}

.rift-fissure {
    position: absolute;
    top: 50%;
    left: 0;
    width: 100%;
    height: 6px;
    transform: translateY(-50%);
    z-index: 4;
    pointer-events: none;
}

#rift-fissure-path {
    stroke-dasharray: 0 4000;
    stroke-dashoffset: 0;
    transition: stroke-dasharray 1500ms var(--ease-geological);
}

#rift-fissure-path.is-drawn {
    stroke-dasharray: 4000 0;
}

.rift-title {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 5;
    font-family: var(--font-display);
    font-weight: 600;
    font-size: clamp(2.4rem, 8vw, 6.4rem);
    letter-spacing: 0.5em;
    white-space: nowrap;
    user-select: none;
    transition: letter-spacing 800ms var(--ease-geological);
}

.rift-title.is-settled {
    letter-spacing: 0.08em;
}

.rift-letter {
    display: inline-block;
    opacity: 0;
    transform: translateY(0);
    transition: opacity 600ms var(--ease-geological);
}

.rift-letter.is-visible {
    opacity: 1;
}

.rift-letter-up {
    color: var(--obsidian);
    transform: translateY(-0.5em);
}

.rift-letter-down {
    color: var(--lichen);
    transform: translateY(0.5em);
}

.rift-letter-dot {
    color: var(--iron-gall);
    transform: translateY(0);
}

.rift-chevron {
    position: absolute;
    bottom: 6vh;
    left: 50%;
    transform: translateX(-50%);
    z-index: 6;
    opacity: 0;
    animation: chevron-appear 800ms var(--ease-geological) 4200ms forwards,
               chevron-pulse 2400ms var(--ease-geological) 5000ms infinite;
}

@keyframes chevron-appear {
    from { opacity: 0; transform: translate(-50%, 6px); }
    to   { opacity: 0.85; transform: translate(-50%, 0); }
}

@keyframes chevron-pulse {
    0%, 100% { opacity: 0.85; transform: translate(-50%, 0); }
    50%      { opacity: 0.4;  transform: translate(-50%, 4px); }
}

.rift-marginalia {
    position: absolute;
    bottom: 4vh;
    right: 4vw;
    z-index: 6;
    color: var(--mist);
    opacity: 0;
    animation: marginalia-fade 1200ms var(--ease-geological) 4600ms forwards;
}

@keyframes marginalia-fade {
    from { opacity: 0; }
    to   { opacity: 0.65; }
}

/* ============================================
   Marginalia (manuscript ambient texture)
   ============================================ */
.marginalia {
    font-family: var(--font-display);
    font-style: italic;
    font-weight: 400;
    font-size: 0.75rem;
    color: var(--mist);
    letter-spacing: 0.04em;
    pointer-events: none;
    user-select: none;
}

.marginalia-left {
    position: absolute;
    left: 2vw;
    top: 14%;
    max-width: 12ch;
    line-height: 1.4;
    opacity: 0;
    transition: opacity 1000ms var(--ease-geological) 400ms;
}

.marginalia-right {
    position: absolute;
    right: 2vw;
    top: 14%;
    max-width: 12ch;
    line-height: 1.4;
    opacity: 0;
    transition: opacity 1000ms var(--ease-geological) 400ms;
}

.reveal-on-scroll.is-revealed .marginalia-left,
.reveal-on-scroll.is-revealed .marginalia-right {
    opacity: 0.6;
}

.logberg-marginalia {
    position: absolute;
    top: 4vh;
    right: 4vw;
    color: var(--vellum-gold);
    opacity: 0;
    transition: opacity 1200ms var(--ease-geological) 600ms;
}

.scene-logberg.is-revealed .logberg-marginalia {
    opacity: 0.7;
}

/* ============================================
   Fissure section dividers
   ============================================ */
.fissure-divider {
    width: 100%;
    height: 8px;
    margin: 0;
    padding: 0;
    overflow: hidden;
    opacity: 1;
}

.fissure-divider svg {
    width: 100%;
    height: 8px;
    display: block;
}

.fissure-divider-path {
    stroke-dasharray: 0 4000;
    transition: stroke-dasharray 1200ms var(--ease-geological);
}

.fissure-divider.is-revealed .fissure-divider-path {
    stroke-dasharray: 4000 0;
}

/* ============================================
   Prose scenes (descent sections)
   ============================================ */
.scene-prose {
    position: relative;
    min-height: 80vh;
    padding: 18vh 0 18vh;
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    column-gap: 1.4vw;
}

.section-left {
    padding-left: 8vw;
    padding-right: 4vw;
}

.section-left .prose-block {
    grid-column: 2 / span 6;
}

.section-right {
    padding-left: 4vw;
    padding-right: 8vw;
}

.section-right .prose-block {
    grid-column: 6 / span 7;
}

.prose-block {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 800ms var(--ease-geological),
                transform 800ms var(--ease-geological);
}

.is-revealed .prose-block {
    opacity: 1;
    transform: translateY(0);
}

.eyebrow {
    font-family: var(--font-mark);
    font-size: 0.75rem;
    font-weight: 500;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--iron-gall);
    margin-bottom: 1.4em;
}

.prose-heading {
    font-family: var(--font-display);
    font-weight: 600;
    font-style: normal;
    font-size: clamp(2rem, 5vw, 4.5rem);
    line-height: 1.08;
    letter-spacing: 0.04em;
    color: var(--obsidian);
    margin-bottom: 0.9em;
    max-width: 18ch;
}

.prose-heading-italic {
    font-weight: 300;
    font-style: italic;
    letter-spacing: 0.02em;
}

.prose-paragraph {
    margin-bottom: 1.2em;
    color: var(--body-on-light);
    font-feature-settings: "liga" 1, "kern" 1;
}

.prose-paragraph-quiet {
    color: var(--basalt);
    font-style: italic;
    font-size: 0.95em;
}

/* ============================================
   Basalt column verticals (margin decoration)
   ============================================ */
.basalt-columns {
    position: absolute;
    top: 14%;
    width: 60px;
    height: 70%;
    pointer-events: none;
    opacity: 0;
    transition: opacity 1200ms var(--ease-geological) 200ms;
    background-image:
        linear-gradient(to right,
            transparent 0px, transparent 4px,
            var(--basalt) 4px, var(--basalt) 5px,
            transparent 5px, transparent 12px,
            var(--basalt) 12px, var(--basalt) 13px,
            transparent 13px, transparent 22px,
            var(--basalt) 22px, var(--basalt) 23px,
            transparent 23px, transparent 30px,
            var(--basalt) 30px, var(--basalt) 31px,
            transparent 31px, transparent 42px,
            var(--basalt) 42px, var(--basalt) 43px,
            transparent 43px, transparent 52px,
            var(--basalt) 52px, var(--basalt) 53px,
            transparent 53px, transparent 60px
        );
}

.basalt-columns-left {
    left: 1.5vw;
}

.basalt-columns-right {
    right: 1.5vw;
}

.is-revealed .basalt-columns {
    opacity: 0.3;
}

/* ============================================
   Scene 3: The Logberg (full-bleed dark)
   ============================================ */
.scene-logberg {
    position: relative;
    min-height: 100vh;
    background-color: var(--peat);
    color: var(--body-on-dark);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    padding: 18vh 6vw;
}

.logberg-clip {
    position: relative;
    max-width: 56ch;
    text-align: center;
    clip-path: circle(0% at 50% 50%);
    transition: clip-path 1200ms var(--ease-geological);
    will-change: clip-path;
}

.scene-logberg.is-revealed .logberg-clip {
    clip-path: circle(120% at 50% 50%);
}

.logberg-quote {
    font-family: var(--font-display);
    font-weight: 300;
    font-style: italic;
    font-size: clamp(1.8rem, 4.4vw, 3.6rem);
    line-height: 1.2;
    letter-spacing: 0.04em;
    color: var(--lichen);
}

.logberg-quote-text {
    display: block;
    min-height: 1.2em;
}

.logberg-quote-text::after {
    content: "";
    display: inline-block;
    width: 1px;
    height: 0.9em;
    background-color: var(--vellum-gold);
    margin-left: 0.12em;
    vertical-align: text-bottom;
    animation: caret-blink 900ms steps(2, jump-none) infinite;
    opacity: 0;
}

.logberg-quote-text.is-typing::after,
.logberg-quote-text.is-typed::after {
    opacity: 1;
}

.logberg-quote-text.is-typed::after {
    animation: caret-fade 1600ms var(--ease-geological) 600ms forwards;
}

@keyframes caret-blink {
    0%, 50%   { opacity: 1; }
    51%, 100% { opacity: 0; }
}

@keyframes caret-fade {
    from { opacity: 1; }
    to   { opacity: 0; }
}

.logberg-cite {
    display: block;
    margin-top: 2.4em;
    font-family: var(--font-mark);
    font-style: normal;
    font-weight: 400;
    font-size: 0.78rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--vellum-gold);
    opacity: 0;
    transition: opacity 1000ms var(--ease-geological);
}

.scene-logberg.is-cite-visible .logberg-cite {
    opacity: 0.85;
}

/* ============================================
   Scene 4: Colophon + Timeline
   ============================================ */
.scene-colophon {
    position: relative;
    min-height: 100vh;
    padding: 18vh 6vw 12vh;
    background-color: var(--lichen);
}

.colophon-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 6vw;
    align-items: start;
    max-width: 1280px;
    margin: 0 auto;
}

.colophon-text {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 900ms var(--ease-geological),
                transform 900ms var(--ease-geological);
}

.is-revealed .colophon-text {
    opacity: 1;
    transform: translateY(0);
}

.colophon-timeline {
    position: relative;
    min-height: 620px;
}

.timeline-svg {
    position: absolute;
    top: 0;
    left: 0;
    width: 200px;
    height: 600px;
    overflow: visible;
}

#timeline-path {
    stroke-dasharray: 0 600;
    transition: stroke-dasharray 2000ms var(--ease-geological);
}

#timeline-path.is-drawn {
    stroke-dasharray: 600 0;
}

.timeline-list {
    position: relative;
    list-style: none;
    margin: 0;
    padding: 0;
    height: 600px;
}

.timeline-item {
    position: absolute;
    top: var(--y);
    left: 0;
    display: flex;
    align-items: baseline;
    gap: 1.4em;
    width: 100%;
    transform: translateY(-10px);
    opacity: 0;
    transition: opacity 600ms var(--ease-geological),
                transform 600ms var(--ease-geological);
}

.timeline-item.is-visible {
    opacity: 1;
    transform: translateY(-10px);
}

.timeline-marker {
    position: relative;
    flex: 0 0 auto;
    width: 12px;
    height: 12px;
    margin-left: 94px;
    background-color: var(--vellum-gold);
    border-radius: 50%;
    transform: scale(0);
    transition: transform 500ms var(--ease-geological),
                box-shadow 500ms var(--ease-geological);
}

.timeline-item.is-visible .timeline-marker {
    transform: scale(1);
}

.timeline-marker:hover {
    transform: scale(1.4);
    box-shadow: 0 0 0 4px rgba(201, 168, 92, 0.18);
}

.timeline-marker-final {
    background-color: var(--iron-gall);
}

.timeline-item-final.is-pulse .timeline-marker-final {
    animation: pulse-attention 1400ms var(--ease-geological) 1;
}

@keyframes pulse-attention {
    0%   { box-shadow: 0 0 0 0 rgba(138, 110, 66, 0.6); transform: scale(1); }
    50%  { box-shadow: 0 0 0 14px rgba(138, 110, 66, 0); transform: scale(1.25); }
    100% { box-shadow: 0 0 0 0 rgba(138, 110, 66, 0); transform: scale(1); }
}

.timeline-year {
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 1.6rem;
    color: var(--obsidian);
    letter-spacing: 0.04em;
    flex: 0 0 auto;
}

.timeline-note {
    font-family: var(--font-body);
    font-size: 0.95rem;
    color: var(--basalt);
    line-height: 1.4;
    flex: 1 1 auto;
}

.colophon-foot {
    margin-top: 10vh;
    text-align: center;
    font-family: var(--font-mark);
    font-size: 0.72rem;
    letter-spacing: 0.32em;
    text-transform: uppercase;
    color: var(--basalt);
    opacity: 0.7;
}

/* ============================================
   Reveal-on-scroll baseline
   ============================================ */
.reveal-on-scroll {
    /* baseline state -- children handle their own transitions */
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 900px) {
    .section-left,
    .section-right {
        padding-left: 6vw;
        padding-right: 6vw;
    }

    .section-left .prose-block,
    .section-right .prose-block {
        grid-column: 1 / span 12;
    }

    .basalt-columns {
        opacity: 0;
    }

    .marginalia-left,
    .marginalia-right {
        display: none;
    }

    .colophon-grid {
        grid-template-columns: 1fr;
        gap: 8vh;
    }

    .colophon-timeline {
        min-height: 640px;
    }

    .rift-title {
        font-size: clamp(2rem, 13vw, 4.6rem);
    }
}

@media (max-width: 560px) {
    .scene-prose {
        padding: 12vh 0 12vh;
    }

    .prose-heading {
        font-size: clamp(1.6rem, 7vw, 2.6rem);
    }

    .timeline-marker {
        margin-left: 60px;
    }

    .timeline-svg {
        width: 140px;
    }
}