/* ============================================================
   saram.ai — Hanji-Light Spectrum / Consciousness Layers
   ============================================================ */

:root {
    /* Palette — Hanji-Light Spectrum */
    --hanji-cream: #F7F3EE;
    --moon-white: #F0EDE8;
    --ink-navy: #0D1B2A;
    --hanbok-pink: #E8A0BF;
    --celadon: #A8D5BA;
    --digital-teal: #4ECDC4;
    --brush-black: #1A1A1A;
    --lantern-gold: #F5D89A;

    /* Dynamic depth properties (mutated by JS / Intersection Observer) */
    --bg-color: var(--hanji-cream);
    --text-color: var(--brush-black);
    --glow-color: var(--hanbok-pink);
    --glow-opacity: 0.10;
    --depth-shade: 0;

    /* Type — The Hanji-Digital System */
    --font-display: "Noto Serif KR", "Noto Serif", Georgia, serif;
    --font-body: "Commissioner", "Inter", system-ui, sans-serif;
    --font-ui: "IBM Plex Sans KR", "IBM Plex Sans", system-ui, sans-serif;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    padding: 0;
    background: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-body);
    font-size: 18px;
    line-height: 1.75;
    overflow-x: hidden;
    transition: background 1.5s ease-in-out, color 1.5s ease-in-out;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* The depth-overlay sits above the page, tinting everything subtly
   so the descent through layers feels atmospheric, not abrupt. */
.depth-overlay {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 200;
    background: radial-gradient(120% 80% at 50% 50%,
        rgba(13, 27, 42, 0) 0%,
        rgba(13, 27, 42, 0) 50%,
        rgba(13, 27, 42, calc(var(--depth-shade) * 0.10)) 100%);
    transition: background 1.5s ease-in-out;
    mix-blend-mode: multiply;
}

/* ============================================================
   Header / Brand
   ============================================================ */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 28px 48px;
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    pointer-events: none;
}

.brand {
    font-family: var(--font-ui);
    font-weight: 400;
    font-size: 15px;
    letter-spacing: 0.06em;
    color: var(--text-color);
    transition: color 1.5s ease-in-out;
}

.brand-mark {
    font-weight: 500;
}

.brand-dot {
    color: var(--hanbok-pink);
    margin: 0 1px;
}

.brand-tld {
    opacity: 0.65;
}

.brand-meta {
    font-family: var(--font-ui);
    font-weight: 300;
    font-size: 12px;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--text-color);
    opacity: 0.55;
    transition: color 1.5s ease-in-out;
}

/* ============================================================
   Layer Navigation (right rail)
   ============================================================ */
.layer-nav {
    position: fixed;
    top: 50%;
    right: 36px;
    transform: translateY(-50%);
    z-index: 110;
    pointer-events: auto;
}

.layer-nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 22px;
}

.layer-nav li {
    display: flex;
    align-items: center;
    gap: 14px;
    cursor: pointer;
    font-family: var(--font-ui);
    font-weight: 300;
    font-size: 11px;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--text-color);
    opacity: 0.4;
    transition: opacity 0.6s ease, color 1.5s ease-in-out;
}

.layer-nav li:hover {
    opacity: 0.85;
}

.layer-nav li.active {
    opacity: 1;
}

.layer-nav .dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: currentColor;
    opacity: 0.35;
    box-shadow: 0 0 0 0 var(--glow-color);
    transition: box-shadow 0.6s ease, opacity 0.6s ease, transform 0.6s ease;
}

.layer-nav li.active .dot {
    opacity: 1;
    transform: scale(1.25);
    box-shadow: 0 0 12px 2px var(--glow-color);
}

.layer-nav .ko {
    font-family: var(--font-display);
    font-weight: 500;
    font-size: 14px;
    letter-spacing: 0.05em;
    text-transform: none;
}

.layer-nav .en {
    opacity: 0.7;
}

/* ============================================================
   Layer Shared
   ============================================================ */
.layer {
    position: relative;
    width: 100%;
    padding: 0 8vw;
    overflow: hidden;
}

.layer-label {
    position: absolute;
    top: 96px;
    left: 8vw;
    display: flex;
    flex-direction: column;
    gap: 4px;
    font-family: var(--font-ui);
    color: var(--text-color);
    z-index: 5;
    transition: color 1.5s ease-in-out;
}

.layer-label .layer-num {
    font-weight: 400;
    font-size: 11px;
    letter-spacing: 0.32em;
    opacity: 0.45;
}

.layer-label .layer-name-ko {
    font-family: var(--font-display);
    font-weight: 500;
    font-size: 22px;
    letter-spacing: 0.04em;
    opacity: 0.85;
}

.layer-label .layer-name-en {
    font-weight: 300;
    font-size: 12px;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    opacity: 0.55;
}

.layer-label-dark {
    color: var(--moon-white);
}

/* ============================================================
   LAYER 1 — Surface / 표면
   ============================================================ */
.layer-1 {
    height: 100vh;
    min-height: 720px;
    background: var(--hanji-cream);
    display: flex;
    align-items: center;
    justify-content: center;
}

.surface-stage {
    position: relative;
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    text-align: center;
}

.hangul-mark {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: clamp(180px, 28vw, 420px);
    line-height: 0.92;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg,
        var(--hanbok-pink) 0%,
        var(--hanbok-pink) 30%,
        var(--celadon) 70%,
        var(--celadon) 100%);
    background-size: 200% 200%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    -webkit-text-fill-color: transparent;
    opacity: 0.78;
    user-select: none;
    animation: hangul-bloom 14s ease-in-out infinite;
    text-shadow: none;
    filter: drop-shadow(0 6px 30px rgba(232, 160, 191, 0.18));
}

.hangul-mark .hangul-char {
    display: inline-block;
    transform-origin: 50% 60%;
}

.hangul-mark .hangul-1 {
    animation: hangul-drift-1 9s ease-in-out infinite;
    margin-right: 0.04em;
}

.hangul-mark .hangul-2 {
    animation: hangul-drift-2 9s ease-in-out infinite;
}

@keyframes hangul-bloom {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

@keyframes hangul-drift-1 {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-6px) rotate(-0.3deg); }
}

@keyframes hangul-drift-2 {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(6px) rotate(0.3deg); }
}

.surface-caption {
    margin-top: 36px;
    font-family: var(--font-body);
    font-weight: 300;
    font-size: 19px;
    line-height: 1.8;
    color: var(--brush-black);
    opacity: 0.7;
}

.surface-line {
    margin: 0;
    letter-spacing: 0.005em;
}

.scroll-hint {
    position: absolute;
    bottom: 56px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
    font-family: var(--font-ui);
    font-weight: 300;
    font-size: 11px;
    letter-spacing: 0.28em;
    text-transform: uppercase;
    color: var(--brush-black);
    opacity: 0.55;
}

.scroll-line {
    width: 1px;
    height: 56px;
    background: linear-gradient(to bottom, transparent 0%, var(--brush-black) 100%);
    animation: scroll-line-pulse 2.6s ease-in-out infinite;
    transform-origin: top center;
}

@keyframes scroll-line-pulse {
    0%, 100% { transform: scaleY(0.4); opacity: 0.3; }
    50% { transform: scaleY(1); opacity: 0.7; }
}

/* ============================================================
   LAYER 2 — Pattern / 무늬 (Jogakbo)
   ============================================================ */
.layer-2 {
    min-height: 150vh;
    background: var(--hanji-cream);
    padding-top: 200px;
    padding-bottom: 160px;
}

.watermark {
    position: absolute;
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 460px;
    line-height: 1;
    color: var(--brush-black);
    opacity: 0.03;
    user-select: none;
    pointer-events: none;
    z-index: 1;
}

.watermark-in {
    top: 12%;
    left: -3%;
    transform: rotate(-4deg);
}

.watermark-gan {
    bottom: 6%;
    right: -2%;
    transform: rotate(3deg);
    font-size: 380px;
    opacity: 0.025;
}

.jogakbo-grid {
    position: relative;
    z-index: 2;
    margin: 80px auto 0;
    max-width: 1280px;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-auto-rows: minmax(240px, auto);
    gap: 3px;
    background: transparent;
}

/* Each patch is a translucent jogakbo fragment.
   Background is layered: a tone wash from the palette,
   plus a faint hanji texture via gradient. */
.patch {
    position: relative;
    padding: 38px 32px;
    background-color: rgba(232, 160, 191, var(--patch-alpha, 0.08));
    background-image: linear-gradient(
        135deg,
        rgba(247, 243, 238, 0.55) 0%,
        rgba(247, 243, 238, 0.25) 100%
    );
    box-shadow:
        0 0 8px 2px rgba(232, 160, 191, 0.22),
        inset 0 0 0 1px rgba(247, 243, 238, 0.5);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    color: var(--brush-black);
    transition: transform 0.9s cubic-bezier(0.2, 0.8, 0.2, 1),
                box-shadow 0.9s ease,
                background-color 0.9s ease;
    will-change: transform;
}

.patch[style*="--patch-tone: cool"] {
    background-color: rgba(168, 213, 186, var(--patch-alpha, 0.08));
    box-shadow:
        0 0 8px 2px rgba(168, 213, 186, 0.28),
        inset 0 0 0 1px rgba(247, 243, 238, 0.5);
}

.patch:hover {
    transform: translateY(-4px);
}

.patch-eyebrow {
    display: block;
    font-family: var(--font-ui);
    font-weight: 400;
    font-size: 11px;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--brush-black);
    opacity: 0.5;
    margin-bottom: 18px;
}

.patch-title {
    margin: 0 0 14px;
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 22px;
    line-height: 1.3;
    letter-spacing: -0.005em;
    color: var(--brush-black);
}

.patch-body {
    margin: 0;
    font-family: var(--font-body);
    font-weight: 400;
    font-size: 15px;
    line-height: 1.7;
    color: var(--brush-black);
    opacity: 0.78;
}

/* Irregular clip-paths — each patch a unique trapezoid-ish shape.
   2-5 degree wobble, no two identical. */
.patch-a {
    grid-column: 1 / span 2;
    grid-row: 1;
    clip-path: polygon(2% 0%, 100% 1%, 98% 100%, 0% 97%);
}

.patch-b {
    grid-column: 3 / span 2;
    grid-row: 1;
    clip-path: polygon(0% 2%, 98% 0%, 100% 96%, 3% 100%);
}

.patch-c {
    grid-column: 1;
    grid-row: 2;
    clip-path: polygon(1% 1%, 99% 3%, 97% 99%, 0% 100%);
}

.patch-d {
    grid-column: 2 / span 2;
    grid-row: 2;
    clip-path: polygon(3% 0%, 100% 2%, 99% 98%, 0% 100%);
}

.patch-e {
    grid-column: 4;
    grid-row: 2;
    clip-path: polygon(0% 3%, 98% 0%, 100% 100%, 2% 97%);
}

.patch-f {
    grid-column: 1 / span 2;
    grid-row: 3;
    clip-path: polygon(0% 1%, 99% 0%, 97% 100%, 2% 98%);
}

.patch-g {
    grid-column: 3;
    grid-row: 3;
    clip-path: polygon(2% 0%, 100% 2%, 98% 99%, 0% 100%);
}

.patch-h {
    grid-column: 4;
    grid-row: 3;
    clip-path: polygon(1% 2%, 99% 0%, 100% 98%, 3% 100%);
}

@media (max-width: 980px) {
    .jogakbo-grid {
        grid-template-columns: repeat(2, 1fr);
        grid-auto-rows: auto;
    }

    .patch,
    .patch-a, .patch-b, .patch-c, .patch-d,
    .patch-e, .patch-f, .patch-g, .patch-h {
        grid-column: span 1;
        grid-row: auto;
    }
}

@media (max-width: 600px) {
    .jogakbo-grid {
        grid-template-columns: 1fr;
    }

    .patch,
    .patch-a, .patch-b, .patch-c, .patch-d,
    .patch-e, .patch-f, .patch-g, .patch-h {
        grid-column: span 1;
    }

    .watermark {
        font-size: 280px;
    }

    .watermark-gan {
        font-size: 220px;
    }
}

/* ============================================================
   LAYER 3 — Connection / 연결
   ============================================================ */
.layer-3 {
    height: 100vh;
    min-height: 760px;
    background: linear-gradient(90deg,
        var(--hanji-cream) 0%,
        var(--hanji-cream) 48%,
        #ECF1EC 52%,
        #ECF1EC 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding-top: 140px;
    padding-bottom: 120px;
}

.split-stage {
    position: relative;
    width: 100%;
    max-width: 1280px;
    flex: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: 0;
    margin: 0 auto;
}

.split-half {
    position: relative;
    padding: 48px 56px;
    z-index: 3;
}

.split-warm {
    text-align: right;
    color: var(--brush-black);
}

.split-cool {
    text-align: left;
    color: var(--brush-black);
}

.split-tag {
    font-family: var(--font-ui);
    font-weight: 400;
    font-size: 11px;
    letter-spacing: 0.34em;
    text-transform: uppercase;
    opacity: 0.55;
    margin-bottom: 32px;
}

.split-warm .split-tag { color: var(--hanbok-pink); }
.split-cool .split-tag { color: var(--digital-teal); }

.split-list {
    list-style: none;
    margin: 0 0 36px;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.split-list li {
    display: inline-flex;
    align-items: center;
    gap: 14px;
    font-family: var(--font-display);
    font-weight: 500;
    font-size: 26px;
    letter-spacing: 0.005em;
    color: var(--brush-black);
}

.split-warm .split-list { align-items: flex-end; }
.split-cool .split-list { align-items: flex-start; }

.split-warm .split-list li { flex-direction: row-reverse; }

.node-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--hanbok-pink);
    box-shadow: 0 0 12px 2px rgba(232, 160, 191, 0.55);
    flex-shrink: 0;
}

.split-cool .node-dot {
    background: var(--digital-teal);
    box-shadow: 0 0 12px 2px rgba(78, 205, 196, 0.55);
}

.node-label {
    font-family: var(--font-display);
    font-weight: 500;
}

.split-caption {
    margin: 0;
    font-family: var(--font-body);
    font-weight: 300;
    font-size: 14px;
    line-height: 1.7;
    color: var(--brush-black);
    opacity: 0.6;
    max-width: 280px;
}

.split-warm .split-caption { margin-left: auto; }

/* The thread canvas spans the entire split-stage and draws SVG
   threads between human and AI nodes. */
.thread-canvas {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 2;
}

.thread-canvas path {
    fill: none;
    stroke: var(--digital-teal);
    stroke-width: 1.5;
    opacity: 0.6;
    filter: drop-shadow(0 0 4px var(--digital-teal));
    stroke-linecap: round;
    transition: opacity 0.6s ease;
}

.connection-line {
    margin: 48px auto 0;
    max-width: 720px;
    text-align: center;
    font-family: var(--font-display);
    font-weight: 500;
    font-size: 18px;
    line-height: 1.7;
    letter-spacing: 0.005em;
    color: var(--brush-black);
    opacity: 0.7;
}

@media (max-width: 820px) {
    .split-stage {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .split-half {
        padding: 24px;
        text-align: center;
    }

    .split-warm, .split-cool { text-align: center; }
    .split-warm .split-list, .split-cool .split-list { align-items: center; }
    .split-warm .split-list li { flex-direction: row; }
    .split-warm .split-caption { margin: 0 auto; }

    .thread-canvas { display: none; }
}

/* ============================================================
   LAYER 4 — Depth / 깊이
   ============================================================ */
.layer-4 {
    min-height: 100vh;
    background: var(--ink-navy);
    color: var(--moon-white);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding-top: 160px;
    padding-bottom: 120px;
    position: relative;
}

/* Subtle starfield-like ambient light */
.layer-4::before {
    content: "";
    position: absolute;
    inset: 0;
    background:
        radial-gradient(2px 2px at 18% 22%, rgba(245, 216, 154, 0.4), transparent 60%),
        radial-gradient(1.5px 1.5px at 72% 38%, rgba(245, 216, 154, 0.3), transparent 60%),
        radial-gradient(2px 2px at 38% 78%, rgba(168, 213, 186, 0.25), transparent 60%),
        radial-gradient(1.5px 1.5px at 88% 64%, rgba(232, 160, 191, 0.3), transparent 60%),
        radial-gradient(1.5px 1.5px at 12% 64%, rgba(245, 216, 154, 0.25), transparent 60%);
    pointer-events: none;
    opacity: 0.7;
}

.depth-stage {
    position: relative;
    width: 100%;
    max-width: 920px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 72px;
    align-items: center;
    text-align: center;
    z-index: 2;
}

.depth-line {
    position: relative;
    margin: 0;
    padding: 40px 48px;
    font-family: var(--font-display);
    font-weight: 500;
    font-size: clamp(20px, 2.4vw, 28px);
    line-height: 1.55;
    letter-spacing: 0.005em;
    color: var(--moon-white);
    max-width: 680px;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 1.4s ease, transform 1.4s ease;
}

.depth-line.visible {
    opacity: 1;
    transform: translateY(0);
}

.depth-line .halo {
    position: absolute;
    inset: -30% -10%;
    background: radial-gradient(closest-side,
        rgba(245, 216, 154, var(--glow-opacity, 0.10)) 0%,
        rgba(245, 216, 154, 0.04) 40%,
        transparent 75%);
    z-index: -1;
    pointer-events: none;
    animation: halo-pulse 4s ease-in-out infinite;
}

.depth-line-1 .halo { animation-delay: 0s; }
.depth-line-2 .halo { animation-delay: 0.8s; }
.depth-line-3 .halo { animation-delay: 1.6s; }
.depth-line-4 .halo { animation-delay: 2.4s; }

@keyframes halo-pulse {
    0%, 100% { opacity: 0.6; transform: scale(1); }
    50% { opacity: 1; transform: scale(1.04); }
}

.depth-line-2 {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: clamp(28px, 3.4vw, 38px);
    color: var(--lantern-gold);
    letter-spacing: -0.01em;
}

.site-footer {
    margin-top: 120px;
    text-align: center;
    color: var(--moon-white);
    z-index: 2;
}

.footer-mark {
    font-family: var(--font-display);
    font-weight: 500;
    font-size: 18px;
    letter-spacing: 0.05em;
    opacity: 0.85;
}

.footer-meta {
    margin-top: 8px;
    font-family: var(--font-ui);
    font-weight: 300;
    font-size: 11px;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    opacity: 0.4;
}

/* ============================================================
   Body state classes — applied by JS as user descends
   These mutate the dynamic depth properties.
   ============================================================ */
body.in-layer-1 {
    --bg-color: var(--hanji-cream);
    --text-color: var(--brush-black);
    --glow-color: var(--hanbok-pink);
    --glow-opacity: 0.10;
    --depth-shade: 0;
}

body.in-layer-2 {
    --bg-color: var(--hanji-cream);
    --text-color: var(--brush-black);
    --glow-color: var(--celadon);
    --glow-opacity: 0.12;
    --depth-shade: 0.15;
}

body.in-layer-3 {
    --bg-color: #F0EDE6;
    --text-color: var(--brush-black);
    --glow-color: var(--digital-teal);
    --glow-opacity: 0.14;
    --depth-shade: 0.35;
}

body.in-layer-4 {
    --bg-color: var(--ink-navy);
    --text-color: var(--moon-white);
    --glow-color: var(--lantern-gold);
    --glow-opacity: 0.10;
    --depth-shade: 1;
}

/* ============================================================
   Reveal-on-scroll utility for patches
   ============================================================ */
.patch {
    opacity: 0;
    transform: translateY(28px) scale(0.985);
}

.patch.in-view {
    opacity: 1;
    transform: translateY(0) scale(1);
    transition: opacity 1.1s ease, transform 1.1s cubic-bezier(0.2, 0.8, 0.2, 1);
}

.patch-a.in-view { transition-delay: 0.05s; }
.patch-b.in-view { transition-delay: 0.15s; }
.patch-c.in-view { transition-delay: 0.10s; }
.patch-d.in-view { transition-delay: 0.20s; }
.patch-e.in-view { transition-delay: 0.30s; }
.patch-f.in-view { transition-delay: 0.18s; }
.patch-g.in-view { transition-delay: 0.25s; }
.patch-h.in-view { transition-delay: 0.32s; }

/* Connection split-half reveal */
.split-half {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 1.2s ease, transform 1.2s ease;
}

.split-half.in-view {
    opacity: 1;
    transform: translateY(0);
}

.split-cool { transition-delay: 0.2s; }