/* ============================================================
   kakuritsu.com — Scandinavian Probability Theater
   Monochrome. Card-grid. Gradient mesh. Cursor-follow.
   Palette: #171717 #525252 #a3a3a3 #d4d4d4 #ebebeb #e5e5e5
            #f0f0f0 #f5f5f5 #fafafa #000000 #ffffff
   ============================================================ */

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

:root {
    --c-certainty: #171717;
    --c-evidence:  #525252;
    --c-prior:     #a3a3a3;
    --c-likelihood:#d4d4d4;
    --c-mesh-a:    #e5e5e5;
    --c-mesh-b:    #ebebeb;
    --c-mesh-c:    #f0f0f0;
    --c-null:      #f5f5f5;
    --c-void:      #fafafa;
    --c-absolute:  #000000;
    --c-white:     #ffffff;

    --gutter: 24px;
    --col: clamp(40px, 6vw, 80px);

    --font-display: "Libre Baskerville", "Lora", Georgia, serif;
    --font-body:    "Inter", "Helvetica Neue", Arial, sans-serif;
    --font-mono:    "JetBrains Mono", "Space Mono", "Courier New", monospace;

    --ease-out: cubic-bezier(0.22, 0.61, 0.36, 1);
}

html, body {
    background: var(--c-void);
    color: var(--c-certainty);
    font-family: var(--font-body);
    font-weight: 400;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

body {
    position: relative;
    min-height: 100vh;
    cursor: default;
}

/* ============================================================
   Cursor Field (the probability sampling instrument)
   ============================================================ */
.cursor-field {
    position: fixed;
    top: 0;
    left: 0;
    width: 240px;
    height: 240px;
    pointer-events: none;
    z-index: 9000;
    transform: translate3d(-50%, -50%, 0);
    background: radial-gradient(circle, rgba(229, 229, 229, 0.65) 0%, rgba(229, 229, 229, 0.22) 40%, transparent 70%);
    mix-blend-mode: multiply;
    opacity: 0;
    transition: opacity 400ms var(--ease-out),
                width 500ms var(--ease-out),
                height 500ms var(--ease-out),
                background 500ms var(--ease-out);
    will-change: transform, width, height;
}

.cursor-field.visible { opacity: 1; }

.cursor-field.mode-distribution {
    width: 240px; height: 240px;
    background: radial-gradient(circle, rgba(212, 212, 212, 0.55) 0%, rgba(229, 229, 229, 0.22) 45%, transparent 75%);
}
.cursor-field.mode-convergence {
    width: 240px; height: 80px;
    background: radial-gradient(ellipse at center, rgba(212, 212, 212, 0.6) 0%, rgba(229, 229, 229, 0.25) 50%, transparent 78%);
}
.cursor-field.mode-scatter {
    width: 280px; height: 280px;
    background:
        radial-gradient(circle at 30% 40%, rgba(212, 212, 212, 0.55) 0%, transparent 22%),
        radial-gradient(circle at 70% 35%, rgba(212, 212, 212, 0.5) 0%, transparent 20%),
        radial-gradient(circle at 50% 70%, rgba(212, 212, 212, 0.55) 0%, transparent 22%),
        radial-gradient(circle at 25% 75%, rgba(229, 229, 229, 0.5) 0%, transparent 20%),
        radial-gradient(circle at 80% 70%, rgba(229, 229, 229, 0.45) 0%, transparent 20%);
}
.cursor-field.mode-terminal {
    width: 40px; height: 40px;
    background: radial-gradient(circle, rgba(23, 23, 23, 0.25) 0%, rgba(23, 23, 23, 0.18) 85%, transparent 100%);
}
.cursor-field.mode-card {
    width: 120px; height: 120px;
    background: radial-gradient(circle, rgba(212, 212, 212, 0.75) 0%, rgba(212, 212, 212, 0.35) 40%, transparent 72%);
}

.cursor-dot {
    position: fixed;
    top: 0;
    left: 0;
    width: 6px;
    height: 6px;
    background: var(--c-certainty);
    border-radius: 50%;
    pointer-events: none;
    z-index: 9001;
    transform: translate3d(-50%, -50%, 0);
    opacity: 0;
    transition: opacity 200ms linear;
    will-change: transform;
}
.cursor-dot.visible { opacity: 0.9; }

/* ============================================================
   Top navigation
   ============================================================ */
.top-nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 28px 40px;
    z-index: 100;
    pointer-events: none;
}
.top-nav > * { pointer-events: auto; }

.brand {
    font-family: var(--font-body);
    font-weight: 300;
    font-size: 0.82rem;
    letter-spacing: 0.15em;
    color: var(--c-evidence);
    text-transform: lowercase;
}

.hamburger {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 36px;
    height: 36px;
    background: transparent;
    border: 0;
    padding: 8px 6px;
    cursor: pointer;
}
.hamburger span {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--c-evidence);
    transform-origin: center;
    transition: transform 260ms var(--ease-out), opacity 180ms linear;
}
.hamburger.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============================================================
   Menu overlay
   ============================================================ */
.menu-overlay {
    position: fixed;
    inset: 0;
    background: rgba(250, 250, 250, 0.72);
    backdrop-filter: blur(22px) saturate(110%);
    -webkit-backdrop-filter: blur(22px) saturate(110%);
    z-index: 90;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 360ms var(--ease-out);
}
.menu-overlay.open { opacity: 1; pointer-events: auto; }

.menu-network {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    opacity: 0.18;
}

.menu-items {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 22px;
    align-items: center;
    z-index: 2;
}
.menu-items a {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: clamp(1.6rem, 3.2vw, 2.8rem);
    letter-spacing: -0.01em;
    line-height: 1.15;
    color: var(--c-certainty);
    text-decoration: none;
    position: relative;
    transition: color 240ms var(--ease-out);
}
.menu-items a::after {
    content: "";
    position: absolute;
    left: 0; bottom: -4px;
    width: 0; height: 1px;
    background: var(--c-evidence);
    transition: width 360ms var(--ease-out);
}
.menu-items a:hover { color: var(--c-evidence); }
.menu-items a:hover::after { width: 100%; }

.menu-footer {
    position: absolute;
    bottom: 40px;
    left: 0; right: 0;
    display: flex;
    justify-content: space-between;
    padding: 0 40px;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--c-prior);
    z-index: 2;
}

/* ============================================================
   Section base
   ============================================================ */
.section {
    position: relative;
    width: 100%;
    overflow: hidden;
}

.mesh {
    position: absolute;
    inset: 0;
    pointer-events: none;
    will-change: transform;
}

.watermark {
    position: absolute;
    font-family: var(--font-mono);
    color: var(--c-mesh-c);
    pointer-events: none;
    user-select: none;
    z-index: 1;
    line-height: 1;
    letter-spacing: -0.02em;
}

.section-header {
    position: relative;
    z-index: 3;
    padding: 0 clamp(24px, 5vw, 72px);
    max-width: 1320px;
    margin: 0 auto;
}

.section-tag {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--c-evidence);
    letter-spacing: 0.04em;
    margin-bottom: 20px;
}

.section-title {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: clamp(1.8rem, 4vw, 3.6rem);
    letter-spacing: -0.01em;
    line-height: 1.15;
    color: var(--c-certainty);
    margin-bottom: 20px;
    max-width: 22ch;
}

.section-lede {
    font-family: var(--font-body);
    font-weight: 300;
    font-size: clamp(0.95rem, 1.6vw, 1.1rem);
    line-height: 1.7;
    letter-spacing: 0.01em;
    color: var(--c-evidence);
    max-width: 56ch;
}

/* ============================================================
   Section 1 — Opening Field
   ============================================================ */
.opening {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 120px 40px 80px;
}

.mesh-opening {
    background:
        radial-gradient(ellipse at 20% 30%, var(--c-mesh-a) 0%, transparent 50%),
        radial-gradient(ellipse at 75% 65%, var(--c-likelihood) 0%, transparent 42%),
        radial-gradient(ellipse at 50% 82%, var(--c-mesh-b) 0%, transparent 55%),
        radial-gradient(ellipse at 85% 20%, var(--c-mesh-c) 0%, transparent 45%);
    animation: mesh-pulse-a 26s ease-in-out infinite alternate;
}

.watermark-opening {
    top: 58%;
    left: 50%;
    transform: translate(-50%, -50%) rotate(-3deg);
    font-size: clamp(5rem, 18vw, 18rem);
    white-space: nowrap;
    z-index: 0;
}

.opening-inner {
    position: relative;
    z-index: 3;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 32px;
    text-align: center;
}

.symbol-svg {
    width: clamp(120px, 20vw, 220px);
    height: clamp(260px, 40vh, 420px);
    overflow: visible;
}

.symbol-path {
    stroke-dasharray: 1200;
    stroke-dashoffset: 1200;
    animation: symbol-draw 2s var(--ease-out) 0.4s forwards;
}

.opening-wordmark {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: clamp(1.2rem, 2.5vw, 1.8rem);
    letter-spacing: 0.2em;
    color: var(--c-evidence);
    text-transform: lowercase;
    opacity: 0;
    animation: fade-up 900ms var(--ease-out) 2.4s forwards;
}

.opening-tagline {
    font-family: var(--font-body);
    font-weight: 300;
    font-size: clamp(0.88rem, 1.3vw, 1rem);
    color: var(--c-prior);
    letter-spacing: 0.01em;
    line-height: 1.6;
    max-width: 44ch;
    opacity: 0;
    animation: fade-up 900ms var(--ease-out) 2.8s forwards;
}

.chevron {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    width: 28px;
    opacity: 0;
    animation: chevron-breathe 3s ease-in-out 3.2s infinite;
}
.chevron svg { width: 100%; height: auto; display: block; }

/* ============================================================
   Section 2 — Distribution Canvas
   ============================================================ */
.distribution {
    min-height: 150vh;
    padding: 140px 0 120px;
}

.mesh-distribution {
    background:
        radial-gradient(ellipse at 18% 22%, var(--c-mesh-a) 0%, transparent 48%),
        radial-gradient(ellipse at 70% 38%, var(--c-likelihood) 0%, transparent 40%),
        radial-gradient(ellipse at 38% 70%, var(--c-mesh-b) 0%, transparent 50%),
        radial-gradient(ellipse at 82% 80%, var(--c-mesh-c) 0%, transparent 45%),
        radial-gradient(ellipse at 55% 92%, var(--c-mesh-a) 0%, transparent 42%);
    animation: mesh-pulse-b 30s ease-in-out infinite alternate;
}

.circuit-bg {
    position: absolute;
    inset: 0;
    opacity: 0.22;
    pointer-events: none;
    z-index: 1;
}
.circuit-bg svg { width: 100%; height: 100%; }

.watermark-distribution {
    top: 6%;
    right: 3%;
    font-size: clamp(1.6rem, 4vw, 3.4rem);
    transform: rotate(2deg);
}

.probability-grid {
    position: relative;
    z-index: 3;
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    grid-auto-rows: 58px;
    gap: var(--gutter);
    padding: 60px clamp(24px, 5vw, 72px) 0;
    max-width: 1320px;
    margin: 0 auto;
}

.p-card {
    grid-column: var(--col-start) / span var(--col-span);
    grid-row: span var(--row-span);
    background: var(--c-null);
    padding: clamp(20px, 2.2vw, 28px);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 14px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
    transition: transform 180ms var(--ease-out),
                box-shadow 180ms var(--ease-out),
                background 180ms var(--ease-out);
    position: relative;
    min-height: 160px;
}

.p-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.09);
    background: var(--c-void);
}

.p-card.center-card {
    background: var(--c-void);
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.07);
}
.p-card.center-card:hover {
    background: var(--c-white);
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.1);
}

.card-meta {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--c-prior);
    letter-spacing: 0.02em;
}

.card-title {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: clamp(1rem, 1.8vw, 1.563rem);
    letter-spacing: -0.01em;
    line-height: 1.2;
    color: var(--c-certainty);
}

.p-card.center-card .card-title {
    font-size: clamp(1.25rem, 2.4vw, 1.953rem);
}

.card-body {
    font-family: var(--font-body);
    font-weight: 300;
    font-size: clamp(0.85rem, 1.3vw, 0.95rem);
    line-height: 1.6;
    color: var(--c-evidence);
    letter-spacing: 0.01em;
    flex-grow: 1;
}

.card-formula {
    font-family: var(--font-mono);
    font-size: clamp(0.8rem, 1.2vw, 0.95rem);
    color: var(--c-absolute);
    letter-spacing: -0.01em;
    padding-top: 10px;
    border-top: 0.5px solid var(--c-likelihood);
}

/* ============================================================
   Section 3 — Convergence Strip
   ============================================================ */
.convergence {
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 100px 40px;
}

.mesh-convergence {
    background:
        radial-gradient(ellipse 80% 30% at 50% 50%, var(--c-mesh-b) 0%, transparent 60%),
        radial-gradient(ellipse 40% 20% at 20% 50%, var(--c-likelihood) 0%, transparent 55%),
        radial-gradient(ellipse 40% 20% at 80% 50%, var(--c-likelihood) 0%, transparent 55%);
    animation: mesh-breathe 22s ease-in-out infinite alternate;
}

.watermark-convergence {
    top: 12%;
    left: 50%;
    transform: translateX(-50%) rotate(-1deg);
    font-size: clamp(4rem, 12vw, 10rem);
    color: var(--c-mesh-c);
}

.convergence-inner {
    position: relative;
    z-index: 3;
    max-width: 38ch;
    text-align: justify;
}

.convergence-title {
    text-align: left;
    margin-bottom: 28px;
    max-width: none;
}

.convergence-copy {
    font-family: var(--font-body);
    font-weight: 300;
    font-size: clamp(0.95rem, 1.5vw, 1.05rem);
    line-height: 1.75;
    color: var(--c-evidence);
    letter-spacing: 0.01em;
    margin-bottom: 36px;
    text-align: justify;
    hyphens: auto;
}

.convergence-formula {
    font-family: var(--font-mono);
    font-size: clamp(1rem, 1.6vw, 1.25rem);
    color: var(--c-absolute);
    letter-spacing: -0.01em;
    text-align: center;
    padding: 20px 0;
    border-top: 0.5px solid var(--c-likelihood);
    border-bottom: 0.5px solid var(--c-likelihood);
}

.convergence-line {
    margin-top: 36px;
    height: 1px;
    background: linear-gradient(to right, transparent, var(--c-likelihood) 20%, var(--c-prior) 50%, var(--c-likelihood) 80%, transparent);
}

/* ============================================================
   Section 4 — Scatter Field
   ============================================================ */
.scatter {
    min-height: 120vh;
    padding: 140px 0 120px;
    position: relative;
}

.mesh-scatter {
    background:
        radial-gradient(ellipse at 12% 18%, var(--c-mesh-c) 0%, transparent 42%),
        radial-gradient(ellipse at 82% 24%, var(--c-likelihood) 0%, transparent 38%),
        radial-gradient(ellipse at 40% 58%, var(--c-mesh-b) 0%, transparent 48%),
        radial-gradient(ellipse at 72% 78%, var(--c-mesh-a) 0%, transparent 45%),
        radial-gradient(ellipse at 22% 90%, var(--c-mesh-c) 0%, transparent 40%);
    animation: mesh-drift 34s ease-in-out infinite alternate;
}

.watermark-scatter {
    top: 8%;
    left: 4%;
    font-size: clamp(1.4rem, 3.4vw, 2.8rem);
    transform: rotate(-4deg);
}

.scatter-header {
    margin-bottom: 60px;
}

.scatter-field {
    position: relative;
    width: 100%;
    max-width: 1320px;
    margin: 0 auto;
    padding: 0 clamp(24px, 5vw, 72px);
    min-height: 90vh;
    z-index: 2;
}

.s-card {
    position: absolute;
    left: var(--x);
    top: var(--y);
    width: clamp(180px, 18vw, 240px);
    transform: rotate(var(--rot));
    background: var(--c-void);
    padding: 20px 22px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
    animation: scatter-drift var(--dur) ease-in-out var(--delay) infinite alternate;
    transition: box-shadow 180ms var(--ease-out);
    will-change: transform;
}
.s-card:hover {
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.1);
    z-index: 4;
}
.s-card .card-title { font-size: clamp(0.98rem, 1.4vw, 1.2rem); }
.s-card .card-body { font-size: 0.85rem; }
.s-card .card-formula { font-size: 0.8rem; padding-top: 8px; }

/* ============================================================
   Section 5 — Terminal Point
   ============================================================ */
.terminal {
    min-height: 60vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 100px 40px 60px;
    position: relative;
}

.mesh-terminal {
    background:
        radial-gradient(circle at 50% 50%, var(--c-mesh-b) 0%, transparent 45%),
        radial-gradient(ellipse at 20% 80%, var(--c-mesh-c) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, var(--c-mesh-c) 0%, transparent 50%);
    animation: mesh-breathe 28s ease-in-out infinite alternate;
}

.ripples {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 100px;
    height: 100px;
    transform: translate(-50%, -50%);
    pointer-events: none;
}

.ripple {
    position: absolute;
    top: 50%; left: 50%;
    width: 300px; height: 180px;
    border: 0.5px solid var(--c-likelihood);
    transform: translate(-50%, -50%);
    opacity: 0;
    animation: ripple-pulse 6s ease-out infinite;
}
.ripple-1 { animation-delay: 0s; }
.ripple-2 { animation-delay: 1.5s; }
.ripple-3 { animation-delay: 3s; }
.ripple-4 { animation-delay: 4.5s; }

.terminal-card {
    position: relative;
    z-index: 3;
    background: var(--c-void);
    padding: clamp(28px, 3.4vw, 48px) clamp(32px, 4vw, 56px);
    max-width: 520px;
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: 16px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}
.terminal-card .card-meta { color: var(--c-evidence); }
.terminal-title {
    font-size: clamp(1.3rem, 2.4vw, 1.953rem);
    margin: 8px 0 4px;
}
.terminal-card .card-formula {
    border-top: 0.5px solid var(--c-likelihood);
    text-align: center;
    margin-top: 6px;
}

.site-footer {
    position: relative;
    z-index: 3;
    margin-top: 80px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 32px;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--c-prior);
    letter-spacing: 0.04em;
}

/* ============================================================
   Animations
   ============================================================ */
@keyframes symbol-draw {
    from { stroke-dashoffset: 1200; }
    to   { stroke-dashoffset: 0; }
}

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

@keyframes chevron-breathe {
    0%   { opacity: 0; transform: translate(-50%, 0); }
    50%  { opacity: 1; transform: translate(-50%, 6px); }
    100% { opacity: 0; transform: translate(-50%, 0); }
}

@keyframes mesh-pulse-a {
    0%   { transform: scale(1) translate(0, 0); }
    100% { transform: scale(1.05) translate(-1%, 1%); }
}
@keyframes mesh-pulse-b {
    0%   { transform: scale(1) translate(0, 0); }
    100% { transform: scale(1.07) translate(1%, -0.5%); }
}
@keyframes mesh-breathe {
    0%, 100% { opacity: 1; transform: scale(1); }
    50%      { opacity: 0.85; transform: scale(1.03); }
}
@keyframes mesh-drift {
    0%   { transform: scale(1) translate(0, 0); }
    50%  { transform: scale(1.04) translate(-0.5%, 0.8%); }
    100% { transform: scale(1.02) translate(0.8%, -0.4%); }
}

@keyframes scatter-drift {
    0%   { transform: rotate(var(--rot)) translate(0, 0); }
    50%  { transform: rotate(calc(var(--rot) + 0.4deg)) translate(8px, -5px); }
    100% { transform: rotate(calc(var(--rot) - 0.4deg)) translate(-6px, 4px); }
}

@keyframes ripple-pulse {
    0%   { width: 120px; height: 80px; opacity: 0; }
    15%  { opacity: 0.75; }
    100% { width: 1100px; height: 660px; opacity: 0; }
}

/* ============================================================
   Reveal on intersect
   ============================================================ */
.p-card, .s-card, .terminal-card, .convergence-inner > *, .section-header > * {
    opacity: 0;
    transform: translateY(12px);
    transition: opacity 700ms var(--ease-out), transform 700ms var(--ease-out);
}
.section-header > * {
    transition-delay: 0ms;
}
.revealed .p-card,
.revealed .s-card,
.revealed .terminal-card,
.revealed .convergence-inner > *,
.revealed .section-header > * {
    opacity: 1;
    transform: translateY(0);
}

/* ============================================================
   Responsive adjustments
   ============================================================ */
@media (max-width: 900px) {
    .probability-grid {
        grid-template-columns: repeat(6, 1fr);
        grid-auto-rows: 70px;
    }
    .p-card {
        grid-column: 1 / span 6 !important;
        grid-row: span 3 !important;
    }
    .p-card.center-card { grid-row: span 4 !important; }

    .s-card {
        width: clamp(200px, 60vw, 300px);
    }

    .menu-footer {
        padding: 0 20px;
        font-size: 0.7rem;
        gap: 20px;
        flex-wrap: wrap;
        justify-content: center;
    }

    .top-nav { padding: 20px 24px; }
}

@media (max-width: 560px) {
    .scatter-field {
        min-height: 180vh;
    }
    .s-card {
        width: 78vw;
    }
    .watermark-distribution,
    .watermark-scatter {
        font-size: 1.4rem;
    }
    .convergence-inner { padding: 0 10px; }
    .site-footer { gap: 18px; font-size: 0.72rem; }
}