/* ============================================
   concurrent.quest - styles.css
   Street-style academic fusion
   ============================================ */

/* --- CSS Custom Properties --- */
:root {
    --asphalt-black: #0D0D0D;
    --carbon: #1A1A1A;
    --poster-white: #F5F5F0;
    --signal-red: #FF3B30;
    --caution-yellow: #FFD600;
    --process-cyan: #00E5FF;
    --faded-chalk: #B8B8A8;
    --concrete-gray: #3D3D3D;
    --concrete-texture: #2A2A2A;
    --stencil-dark: #1A1A1A;
    --stencil-light: #E8E8E0;

    --font-anton: 'Anton', sans-serif;
    --font-archivo: 'Archivo Black', sans-serif;
    --font-plex: 'IBM Plex Mono', monospace;
    --font-space: 'Space Mono', monospace;
}

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

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

body {
    background-color: var(--asphalt-black);
    color: var(--poster-white);
    font-family: var(--font-plex);
    overflow-x: hidden;
    position: relative;
    /* Concrete texture: layered subtle gradients using #2A2A2A and #3D3D3D */
    background-image:
        radial-gradient(ellipse at 20% 50%, #2A2A2A08 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, #3D3D3D05 0%, transparent 50%),
        radial-gradient(ellipse at 50% 80%, #2A2A2A08 0%, transparent 50%);
}

/* --- Noise Grain Overlay --- */
body::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    opacity: 0.04;
    filter: url(#noise-grain);
    will-change: transform;
}

/* --- Margin Rail --- */
.margin-rail {
    position: fixed;
    top: 0;
    left: 0;
    width: 60px;
    height: 100vh;
    background-color: var(--carbon);
    border-right: 1px solid var(--signal-red);
    z-index: 100;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 30px;
    padding: 20px 6px;
    overflow: hidden;
    opacity: 0;
    transition: opacity 400ms ease;
}

.margin-rail.visible {
    opacity: 1;
}

.rail-annotation {
    display: flex;
    flex-direction: column;
    gap: 2px;
    opacity: 0;
    transition: opacity 300ms ease;
}

.rail-annotation.active {
    opacity: 1;
}

.rail-num {
    font-family: var(--font-space);
    font-size: 0.7rem;
    font-style: italic;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--signal-red);
    opacity: 0.8;
}

.rail-text {
    font-family: var(--font-space);
    font-size: 0.6rem;
    font-style: italic;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--signal-red);
    opacity: 0.6;
    writing-mode: vertical-rl;
    text-orientation: mixed;
    transform: rotate(180deg);
    max-height: 120px;
    overflow: hidden;
}

/* --- Poster Sections (Shared) --- */
.poster-section {
    position: relative;
    width: 100%;
    min-height: 100vh;
    overflow: hidden;
    padding-left: 60px; /* margin rail offset */
}

.poster-section + .poster-section {
    margin-top: -15vh;
    z-index: 1;
}

#section1 { z-index: 1; }
#section2 { z-index: 2; }
#section3 { z-index: 3; }
#section4 { z-index: 4; }
#section5 { z-index: 5; }
#section6 { z-index: 6; }

.section-dark {
    background-color: var(--asphalt-black);
    color: var(--poster-white);
}

.section-light {
    background-color: var(--poster-white);
    color: var(--asphalt-black);
}

/* --- Section Grid (6-column, 8-row) --- */
.section-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    grid-template-rows: repeat(8, 1fr);
    width: 100%;
    height: 100vh;
    padding: 2rem;
    position: relative;
    z-index: 2;
}

/* --- Stencil Numbers --- */
.stencil-number {
    position: absolute;
    font-family: var(--font-anton);
    font-size: clamp(15rem, 30vw, 25rem);
    line-height: 0.85;
    color: var(--stencil-dark);
    opacity: 0.06;
    z-index: 0;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    pointer-events: none;
    user-select: none;
}

.stencil-light {
    color: var(--stencil-light);
}

.stencil-yellow {
    color: var(--caution-yellow);
    opacity: 0.06;
}

/* --- Bracket Motifs --- */
.bracket-motif {
    position: absolute;
    font-family: var(--font-anton);
    font-size: clamp(20rem, 25vw, 30rem);
    line-height: 1;
    opacity: 0.04;
    z-index: 0;
    pointer-events: none;
    user-select: none;
    color: var(--poster-white);
}

.bracket-left {
    top: 10%;
    left: 5%;
}

.bracket-right {
    bottom: 10%;
    right: 5%;
}

.bracket-angle-left {
    top: 15%;
    left: 3%;
}

.bracket-angle-right {
    bottom: 15%;
    right: 3%;
}

/* --- Warning Stripes --- */
.warning-stripe {
    position: absolute;
    left: 0;
    width: 100%;
    height: 20px;
    background: repeating-linear-gradient(
        45deg,
        var(--caution-yellow),
        var(--caution-yellow) 8px,
        var(--asphalt-black) 8px,
        var(--asphalt-black) 16px
    );
    z-index: 10;
}

.warning-stripe-top {
    top: 0;
}

.warning-stripe-bottom {
    bottom: 0;
}

/* ============================================
   SECTION 1: HERO
   ============================================ */
.hero-title {
    grid-column: 1 / 7;
    grid-row: 2 / 6;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    opacity: 0;
    transform: scale(1.05);
    transition: opacity 600ms cubic-bezier(0.65, 0, 0.35, 1),
                transform 600ms cubic-bezier(0.65, 0, 0.35, 1);
}

.hero-title.animate-in {
    opacity: 1;
    transform: scale(1);
}

.hero-concurrent {
    font-family: var(--font-anton);
    font-size: clamp(3.5rem, 10vw, 9rem);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    line-height: 0.92;
    color: var(--poster-white);
    display: block;
}

.hero-quest {
    font-family: var(--font-anton);
    font-size: clamp(3.5rem, 10vw, 9rem);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    line-height: 0.92;
    color: var(--signal-red);
    display: block;
}

.hero-subtitle {
    grid-column: 2 / 6;
    grid-row: 6 / 7;
    font-family: var(--font-plex);
    font-size: clamp(0.85rem, 1.1vw, 1.05rem);
    line-height: 1.7;
    letter-spacing: 0.01em;
    color: var(--faded-chalk);
    text-align: center;
    align-self: start;
    opacity: 0;
    transition: opacity 600ms ease 800ms;
}

.hero-subtitle.animate-in {
    opacity: 1;
}

/* ============================================
   SECTION 2: DIAGRAM WALL
   ============================================ */
.diagram-heading {
    grid-column: 1 / 5;
    grid-row: 1 / 3;
    display: flex;
    align-items: flex-end;
    padding-top: 30px;
}

.heading-archivo {
    font-family: var(--font-archivo);
    font-size: clamp(1.2rem, 3vw, 2.4rem);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--asphalt-black);
}

.diagram-container {
    grid-column: 1 / 7;
    grid-row: 2 / 7;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.concurrency-svg {
    width: 100%;
    max-width: 800px;
    height: auto;
}

/* SVG Thread Diagram Styles */
.thread-line {
    stroke-width: 3;
    fill: none;
    filter: url(#roughen);
}

.thread-red {
    stroke: var(--signal-red);
}

.thread-cyan {
    stroke: var(--process-cyan);
}

.sync-line {
    stroke-width: 2;
    fill: none;
    stroke-dasharray: 6, 4;
}

.sync-red {
    stroke: var(--signal-red);
}

.sync-cyan {
    stroke: var(--process-cyan);
}

.sync-node {
    fill: none;
    stroke-width: 2;
}

.node-red {
    stroke: var(--signal-red);
    fill: var(--signal-red);
    opacity: 0.8;
}

.node-cyan {
    stroke: var(--process-cyan);
    fill: var(--process-cyan);
    opacity: 0.8;
}

.exec-block {
    opacity: 0.3;
    rx: 2;
}

.block-red {
    fill: var(--signal-red);
}

.block-cyan {
    fill: var(--process-cyan);
}

.wait-line {
    stroke: var(--concrete-gray);
    stroke-width: 1;
    stroke-dasharray: 4, 4;
    opacity: 0.5;
}

.thread-label {
    font-family: var(--font-space);
    font-size: 14px;
    fill: var(--asphalt-black);
    text-anchor: middle;
    font-weight: 400;
}

.thread-label-dark {
    fill: var(--poster-white);
}

/* SVG draw animation */
.thread-line,
.sync-line,
.mutex-path {
    stroke-dasharray: 1000;
    stroke-dashoffset: 1000;
    transition: stroke-dashoffset 1.2s cubic-bezier(0.65, 0, 0.35, 1);
}

.draw-animate .thread-line,
.draw-animate .sync-line,
.draw-animate .mutex-path {
    stroke-dashoffset: 0;
}

.diagram-caption {
    grid-column: 2 / 6;
    grid-row: 7 / 9;
    display: flex;
    align-items: flex-start;
}

/* --- Body Text --- */
.body-text {
    font-family: var(--font-plex);
    font-size: clamp(0.85rem, 1.1vw, 1.05rem);
    line-height: 1.7;
    letter-spacing: 0.01em;
    color: var(--faded-chalk);
}

.body-dark {
    color: var(--asphalt-black);
    opacity: 0.85;
}

/* ============================================
   SECTION 3: MANIFESTO
   ============================================ */
#section3 .section-grid {
    padding-top: 6rem;
    padding-bottom: 4rem;
}

.manifesto-content {
    grid-column: 2 / 6;
    grid-row: 1 / 9;
    display: flex;
    flex-direction: column;
    justify-content: center;
    overflow-y: auto;
}

.manifesto-text {
    display: flex;
    flex-direction: column;
    gap: 1.8rem;
}

.manifesto-text .body-text {
    font-weight: 400;
}

.pull-quote {
    font-family: var(--font-archivo);
    font-size: clamp(1.1rem, 2.5vw, 2rem);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--signal-red);
    line-height: 1.3;
    padding: 1.5rem 0;
    border-left: 4px solid var(--signal-red);
    padding-left: 1.5rem;
}

/* ============================================
   SECTION 4: RACE CONDITION
   ============================================ */
.race-heading {
    grid-column: 1 / 7;
    grid-row: 1 / 2;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    padding-top: 30px;
}

.heading-anton {
    font-family: var(--font-anton);
    font-size: clamp(2rem, 5vw, 4.5rem);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    line-height: 0.92;
    color: var(--poster-white);
}

.heading-yellow {
    color: var(--caution-yellow);
}

.heading-dark {
    color: var(--asphalt-black);
}

.race-diagram-container {
    grid-column: 1 / 7;
    grid-row: 2 / 7;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.shared-resource {
    fill: var(--signal-red);
    opacity: 0.2;
    stroke: var(--signal-red);
    stroke-width: 2;
}

.resource-label {
    font-family: var(--font-space);
    font-size: 14px;
    fill: var(--poster-white);
    text-anchor: middle;
    font-weight: 400;
    letter-spacing: 0.1em;
}

.collision-pulse {
    fill: var(--signal-red);
    opacity: 0;
    transition: opacity 300ms ease;
}

.collision-pulse.flash {
    animation: collisionFlash 800ms ease-out forwards;
}

@keyframes collisionFlash {
    0% { opacity: 0; r: 30; }
    20% { opacity: 0.5; r: 60; }
    100% { opacity: 0; r: 90; }
}

.thread-after {
    opacity: 0.5;
    stroke-dasharray: 5, 5;
}

.corruption-label {
    font-family: var(--font-space);
    font-size: 12px;
    fill: var(--signal-red);
    font-style: italic;
    text-anchor: middle;
    opacity: 0.7;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.race-text {
    grid-column: 2 / 6;
    grid-row: 7 / 9;
    display: flex;
    align-items: flex-start;
}

/* ============================================
   SECTION 5: THE RESOLUTION
   ============================================ */
.resolution-heading {
    grid-column: 1 / 7;
    grid-row: 1 / 2;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    padding-top: 30px;
}

.mutex-diagram-container {
    grid-column: 1 / 7;
    grid-row: 2 / 7;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    position: relative;
}

.mutex-path {
    stroke-width: 3;
    fill: none;
    filter: url(#roughen);
}

.path-cyan {
    stroke: var(--process-cyan);
}

.path-red {
    stroke: var(--signal-red);
}

.mutex-block {
    fill: none;
    stroke: var(--process-cyan);
    stroke-width: 3;
}

.mutex-label {
    font-family: var(--font-space);
    font-size: 16px;
    fill: var(--asphalt-black);
    text-anchor: middle;
    font-weight: 400;
    letter-spacing: 0.1em;
}

.wait-indicator {
    stroke: var(--signal-red);
    stroke-width: 1;
    opacity: 0.6;
}

.wait-text {
    font-family: var(--font-space);
    font-size: 11px;
    fill: var(--signal-red);
    font-style: italic;
    opacity: 0.7;
}

.lock-icon {
    fill: none;
    stroke: var(--asphalt-black);
    stroke-width: 2;
}

.lock-body {
    fill: var(--asphalt-black);
    opacity: 0.7;
}

.hover-node {
    fill: transparent;
    stroke: transparent;
    stroke-width: 2;
    cursor: pointer;
    transition: transform 200ms ease-out;
}

.diagram-node-group:hover .hover-node {
    fill: rgba(0, 229, 255, 0.15);
    stroke: var(--process-cyan);
    transform-origin: center;
}

.diagram-tooltip {
    position: absolute;
    background: var(--asphalt-black);
    color: var(--poster-white);
    font-family: var(--font-space);
    font-size: 0.7rem;
    font-style: italic;
    letter-spacing: 0.04em;
    padding: 8px 14px;
    border: 1px solid var(--process-cyan);
    border-radius: 2px;
    pointer-events: none;
    opacity: 0;
    transition: opacity 200ms ease;
    z-index: 20;
    max-width: 260px;
    white-space: normal;
}

.diagram-tooltip.visible {
    opacity: 1;
}

.resolution-text {
    grid-column: 2 / 6;
    grid-row: 7 / 9;
    display: flex;
    align-items: flex-start;
}

/* ============================================
   SECTION 6: CLOSING
   ============================================ */
#section6 .section-grid {
    align-content: center;
    justify-content: center;
}

.closing-content {
    grid-column: 1 / 7;
    grid-row: 2 / 7;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    gap: 1.5rem;
}

.closing-word {
    font-family: var(--font-anton);
    font-size: clamp(8rem, 20vw, 18rem);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    line-height: 0.92;
    color: var(--signal-red);
}

.closing-subtitle {
    font-family: var(--font-plex);
    font-size: clamp(0.85rem, 1.1vw, 1.05rem);
    line-height: 1.7;
    letter-spacing: 0.01em;
    color: var(--faded-chalk);
}

.closing-stripe {
    bottom: 40px;
}

.footer-domain {
    position: absolute;
    bottom: 12px;
    left: 0;
    width: 100%;
    text-align: center;
    font-family: var(--font-space);
    font-size: 0.8rem;
    letter-spacing: 0.08em;
    text-transform: lowercase;
    color: var(--faded-chalk);
    opacity: 0.6;
    z-index: 11;
}

/* ============================================
   RESPONSIVE: Below 768px
   ============================================ */
@media (max-width: 768px) {
    .margin-rail {
        display: none;
    }

    .poster-section {
        padding-left: 0;
        min-height: 80vh;
        height: auto;
    }

    .poster-section + .poster-section {
        margin-top: -8vh;
    }

    .section-grid {
        grid-template-columns: repeat(4, 1fr);
        height: auto;
        min-height: 80vh;
        padding: 1.5rem;
    }

    .hero-title {
        grid-column: 1 / 5;
        grid-row: 2 / 5;
    }

    .hero-subtitle {
        grid-column: 1 / 5;
        grid-row: 5 / 6;
    }

    .diagram-heading {
        grid-column: 1 / 5;
    }

    .diagram-container {
        grid-column: 1 / 5;
    }

    .diagram-caption {
        grid-column: 1 / 5;
    }

    .manifesto-content {
        grid-column: 1 / 5;
    }

    .race-heading {
        grid-column: 1 / 5;
    }

    .race-diagram-container {
        grid-column: 1 / 5;
    }

    .race-text {
        grid-column: 1 / 5;
    }

    .resolution-heading {
        grid-column: 1 / 5;
    }

    .mutex-diagram-container {
        grid-column: 1 / 5;
    }

    .resolution-text {
        grid-column: 1 / 5;
    }

    .closing-content {
        grid-column: 1 / 5;
    }

    .bracket-motif {
        display: none;
    }

    .stencil-number {
        font-size: clamp(8rem, 20vw, 15rem);
    }

    .pull-quote {
        font-size: clamp(1rem, 2vw, 1.5rem);
    }
}

/* ============================================
   RESPONSIVE: Below 480px
   ============================================ */
@media (max-width: 480px) {
    .hero-concurrent,
    .hero-quest {
        font-size: clamp(2.5rem, 12vw, 4rem);
    }

    .closing-word {
        font-size: clamp(4rem, 15vw, 8rem);
    }

    .heading-anton {
        font-size: clamp(1.5rem, 6vw, 2.5rem);
    }
}