/* =============================================
   hangeul.day — Styles
   Swiss Typographic Exhibition + Lens-Flare
   ============================================= */

/* --- Custom Properties --- */
:root {
    /* Palette */
    --ground: #E8E3DA;
    --surface: #F4F1EB;
    --text-primary: #2B2B3D;
    --text-secondary: #4A4A58;
    --text-tertiary: #9E97A8;
    --grid-lines: #C4BAA8;
    --flare-warm: #D4A46A;
    --flare-cool: #7BA3C9;
    --flare-rose: #C98BAA;
    --emphasis: #35354A;
    --text-annotation: #7A7686;
    --ground-cool: #E3E5EA;

    /* Typography fluid sizes */
    --fs-display: clamp(2.4rem, 5vw + 1rem, 7.2rem);
    --fs-body: clamp(0.95rem, 1vw + 0.6rem, 1.15rem);
    --fs-korean: clamp(1rem, 1.2vw + 0.5rem, 1.3rem);
    --fs-mono: 12px;

    /* Grid */
    --grid-columns: 12;
    --grid-gap: 1.6vw;
    --max-width: 1440px;

    /* Stagger animation */
    --stagger-delay: 120ms;
    --stagger-ease: cubic-bezier(0.16, 1, 0.3, 1);

    /* Background interpolation */
    --bg-progress: 0;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    overflow-x: hidden;
}

body {
    font-family: 'Inter', 'Helvetica', sans-serif;
    font-weight: 400;
    font-optical-sizing: auto;
    color: var(--text-secondary);
    background-color: var(--ground);
    line-height: 1.68;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* --- Grid Container --- */
.grid-container {
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    gap: var(--grid-gap);
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--grid-gap);
    position: relative;
    width: 100%;
}

/* --- Sections --- */
.section {
    position: relative;
    width: 100%;
    overflow: hidden;
}

/* --- Lens Flare Layer --- */
.lens-flare-layer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 100;
    overflow: hidden;
}

.flare-streak {
    position: absolute;
    height: 2px;
    border-radius: 1px;
    opacity: 0;
    will-change: transform;
    transition: opacity 0.6s ease;
}

.flare-streak-1 {
    width: 60vw;
    top: 25%;
    left: -10%;
    background: linear-gradient(90deg, transparent, rgba(212,164,106,0.4), rgba(123,163,201,0.3), transparent);
}

.flare-streak-2 {
    width: 45vw;
    top: 48%;
    left: 20%;
    background: linear-gradient(90deg, transparent, rgba(123,163,201,0.35), rgba(201,139,170,0.2), transparent);
    height: 1px;
}

.flare-streak-3 {
    width: 70vw;
    top: 65%;
    left: -5%;
    background: linear-gradient(90deg, transparent 5%, rgba(212,164,106,0.25), rgba(123,163,201,0.25), rgba(201,139,170,0.15), transparent 95%);
    height: 3px;
}

.flare-streak-4 {
    width: 35vw;
    top: 82%;
    left: 40%;
    background: linear-gradient(90deg, transparent, rgba(201,139,170,0.3), rgba(212,164,106,0.2), transparent);
    height: 1px;
}

.flare-streak-5 {
    width: 50vw;
    top: 15%;
    left: 30%;
    background: linear-gradient(90deg, transparent, rgba(123,163,201,0.2), transparent);
    height: 1px;
    transform: rotate(-2deg);
}

.flare-streak.visible {
    opacity: 1;
}

/* =============================================
   Section 1: Opening Frame
   ============================================= */
.section-opening {
    height: 100vh;
    min-height: 700px;
    display: flex;
    align-items: center;
    position: relative;
    background-color: var(--ground);
}

.section-opening .grid-container {
    align-items: center;
    height: 100%;
}

.opening-character-wrap {
    grid-column: 2 / 6;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

.monumental-char {
    width: 100%;
    max-width: 400px;
    height: auto;
    color: var(--text-primary);
    filter: drop-shadow(0 0 60px rgba(212,164,106,0.08));
}

.bloom-halo {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 140%;
    height: 140%;
    background: radial-gradient(ellipse at center, rgba(212,164,106,0.12), transparent 70%);
    pointer-events: none;
    z-index: -1;
}

.opening-title-line {
    grid-column: 2 / 9;
    position: absolute;
    top: 61.8%;
    left: 0;
    right: 0;
    padding: 0 var(--grid-gap);
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.golden-rule {
    flex: 1;
    border: none;
    height: 1px;
    background: var(--grid-lines);
}

.site-title {
    font-family: 'Inter', sans-serif;
    font-weight: 500;
    font-size: 14px;
    color: var(--text-secondary);
    letter-spacing: 0.06em;
    text-transform: lowercase;
    white-space: nowrap;
}

.site-subtitle {
    font-family: 'Inter', sans-serif;
    font-weight: 300;
    font-size: 12px;
    color: var(--text-tertiary);
    letter-spacing: 0.04em;
    white-space: nowrap;
}

.opening-float-char {
    grid-column: 9 / 13;
    display: flex;
    align-items: center;
    justify-content: center;
    will-change: transform;
}

.float-hangul {
    font-family: 'Noto Serif KR', serif;
    font-size: 40vw;
    font-weight: 300;
    color: var(--text-primary);
    opacity: 0.04;
    line-height: 1;
    user-select: none;
}

.scroll-hint {
    position: absolute;
    bottom: 3rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
}

.scroll-hint-text {
    font-family: 'IBM Plex Mono', monospace;
    font-size: var(--fs-mono);
    color: var(--text-tertiary);
    letter-spacing: 0.04em;
}

.scroll-hint-line {
    width: 1px;
    height: 40px;
    background: var(--grid-lines);
    animation: scrollPulse 2s ease-in-out infinite;
}

@keyframes scrollPulse {
    0%, 100% { opacity: 0.3; transform: scaleY(1); }
    50% { opacity: 1; transform: scaleY(1.3); }
}

/* =============================================
   Section 2: History Corridor
   ============================================= */
.section-history {
    min-height: 200vh;
    position: relative;
}

.history-frame {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding: 6rem 0;
}

.history-frame-1 {
    background-color: var(--ground);
}

.history-frame-2 {
    background-color: color-mix(in srgb, var(--ground) 90%, var(--surface) 10%);
}

.history-content {
    position: relative;
    z-index: 2;
}

.history-content.left-gravity {
    grid-column: 2 / 8;
}

.history-content.right-gravity {
    grid-column: 5 / 12;
}

.mono-label {
    font-family: 'IBM Plex Mono', monospace;
    font-size: var(--fs-mono);
    font-weight: 400;
    color: var(--text-tertiary);
    letter-spacing: 0.04em;
    display: block;
    margin-bottom: 1.5rem;
}

.history-heading {
    font-family: 'Playfair Display', serif;
    font-size: var(--fs-display);
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.1;
    margin-bottom: 2rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0 0.3em;
}

.history-body {
    font-family: 'Inter', sans-serif;
    font-size: var(--fs-body);
    color: var(--text-secondary);
    line-height: 1.68;
    max-width: 540px;
    margin-bottom: 1.5rem;
}

.history-body em,
.korean-quote {
    font-family: 'Noto Serif KR', serif;
    font-style: italic;
    font-weight: 400;
    color: var(--text-primary);
}

.history-body-secondary {
    font-family: 'Inter', sans-serif;
    font-size: var(--fs-body);
    color: var(--text-annotation); /* #7A7686 */
    line-height: 1.68;
    max-width: 540px;
}

.history-timeline {
    grid-column: 12 / 13;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 2rem;
    padding-top: 2rem;
}

.timeline-marker {
    font-family: 'IBM Plex Mono', monospace;
    font-size: var(--fs-mono);
    color: var(--text-tertiary);
    letter-spacing: 0.04em;
    opacity: 0.5;
    transition: opacity 0.4s ease;
}

.timeline-marker.active {
    opacity: 1;
    color: var(--text-secondary);
}

.history-float-char {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    will-change: transform;
    z-index: 1;
}

.float-hangul.large {
    font-size: 40vw;
    opacity: 0.03;
}

/* --- Bojagi Pattern --- */
.bojagi-pattern {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2px;
    width: 80px;
    height: 80px;
    margin-top: 2rem;
}

.bojagi-cell {
    background-color: var(--grid-lines);
    opacity: 0.3;
    border-radius: 1px;
}

.bojagi-cell:nth-child(2n) {
    background-color: var(--flare-warm);
    opacity: 0.2;
}

.bojagi-cell:nth-child(3n) {
    background-color: var(--ground);
    opacity: 0.5;
}

.bojagi-cell:nth-child(5n) {
    background-color: var(--flare-cool);
    opacity: 0.15;
}

/* =============================================
   Section 3: Anatomy Theater
   ============================================= */
.section-anatomy {
    min-height: 200vh;
    position: relative;
    background-color: var(--surface);
}

/* Visible Swiss grid overlay */
.visible-grid-overlay {
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: var(--max-width);
    height: 100%;
    display: grid;
    grid-template-columns: repeat(13, 1fr);
    pointer-events: none;
    z-index: 1;
    opacity: 0;
    transition: opacity 0.8s ease;
    padding: 0 var(--grid-gap);
}

.visible-grid-overlay.visible {
    opacity: 1;
}

.grid-line {
    width: 1px;
    height: 100%;
    background: var(--grid-lines);
    opacity: 0.4;
    justify-self: start;
}

/* Specimen ruled lines */
.specimen-rules {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: repeating-linear-gradient(
        to bottom,
        transparent,
        transparent 7px,
        rgba(196,186,168,0.12) 7px,
        rgba(196,186,168,0.12) 8px
    );
    pointer-events: none;
    z-index: 0;
}

.anatomy-frame {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    position: relative;
    padding: 6rem 0;
    z-index: 2;
}

.anatomy-content {
    position: relative;
    z-index: 3;
}

.anatomy-content.left-gravity {
    grid-column: 2 / 8;
}

.anatomy-content.right-gravity {
    grid-column: 5 / 12;
}

.anatomy-heading {
    font-family: 'Playfair Display', serif;
    font-size: var(--fs-display);
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.1;
    margin-bottom: 2rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0 0.3em;
}

.anatomy-body {
    font-family: 'Inter', sans-serif;
    font-size: var(--fs-body);
    color: var(--text-secondary);
    line-height: 1.68;
    max-width: 540px;
    margin-bottom: 3rem;
}

/* --- Specimen Cards --- */
.consonant-specimens,
.vowel-specimens {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 calc(var(--grid-gap) + 8.333%);
    position: relative;
    z-index: 3;
}

.specimen-card {
    background: var(--surface);
    border: 1px solid rgba(196,186,168,0.4);
    padding: 2rem 1.5rem;
    flex: 1 1 140px;
    max-width: 200px;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    transition: border-color 0.3s ease;
}

.specimen-card:hover {
    border-color: var(--flare-warm);
}

.specimen-char {
    font-family: 'Noto Serif KR', serif;
    font-size: clamp(2.5rem, 4vw, 4rem);
    font-weight: 400;
    color: var(--text-primary);
    line-height: 1.2;
    text-shadow:
        1px 0 2px rgba(201,139,170,0.15),
        -1px 0 2px rgba(123,163,201,0.15);
}

.specimen-label {
    font-family: 'Inter', sans-serif;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-transform: capitalize;
}

.specimen-code {
    font-family: 'IBM Plex Mono', monospace;
    font-size: var(--fs-mono);
    color: var(--text-tertiary);
    letter-spacing: 0.04em;
}

.specimen-desc {
    font-family: 'Inter', sans-serif;
    font-size: 0.75rem;
    color: var(--text-tertiary);
    line-height: 1.5;
}

/* =============================================
   Section 4: Resonance Gallery
   ============================================= */
.section-gallery {
    min-height: 400vh;
    position: relative;
}

.gallery-frame {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding: 4rem 0;
}

.gallery-frame-1 {
    background-color: var(--ground);
}
.gallery-frame-2 {
    background-color: color-mix(in srgb, var(--ground) 95%, var(--ground-cool) 5%);
}
.gallery-frame-3 {
    background-color: color-mix(in srgb, var(--ground) 85%, var(--ground-cool) 15%);
}
.gallery-frame-4 {
    background-color: color-mix(in srgb, var(--ground) 75%, var(--ground-cool) 25%);
}

.gallery-content {
    position: relative;
    z-index: 2;
}

.gallery-content.left-gravity {
    grid-column: 2 / 9;
}

.gallery-content.right-gravity {
    grid-column: 4 / 12;
}

.gallery-syllable {
    margin-bottom: 2rem;
}

.gallery-char {
    font-family: 'Noto Serif KR', serif;
    font-size: clamp(8rem, 20vw, 20rem);
    font-weight: 300;
    color: var(--text-primary);
    line-height: 1;
    display: block;
    text-shadow:
        2px 0 4px rgba(201,139,170,0.1),
        -2px 0 4px rgba(123,163,201,0.1);
}

.gallery-annotation {
    max-width: 480px;
}

.gallery-poem {
    font-family: 'Noto Serif KR', serif;
    font-size: var(--fs-korean);
    font-weight: 400;
    color: var(--text-secondary);
    line-height: 1.85;
    margin-top: 0.75rem;
}

/* Gallery lens flare accents */
.gallery-flare-accent {
    position: absolute;
    top: 40%;
    left: 0;
    width: 80%;
    height: 2px;
    background: linear-gradient(90deg, transparent, rgba(212,164,106,0.35), rgba(123,163,201,0.25), transparent);
    pointer-events: none;
    z-index: 1;
    transform: rotate(-3deg);
}

.gallery-flare-accent.accent-cool {
    background: linear-gradient(90deg, transparent, rgba(123,163,201,0.4), rgba(212,164,106,0.15), transparent);
    transform: rotate(2deg);
    top: 55%;
}

.gallery-flare-accent.accent-rose {
    background: linear-gradient(90deg, transparent, rgba(201,139,170,0.35), rgba(212,164,106,0.2), transparent);
    transform: rotate(-1.5deg);
    top: 35%;
}

.gallery-flare-accent.accent-warm {
    background: linear-gradient(90deg, transparent, rgba(212,164,106,0.45), rgba(201,139,170,0.15), transparent);
    transform: rotate(4deg);
    top: 60%;
}

/* =============================================
   Section 5: Closing Seal
   ============================================= */
.section-closing {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background-color: var(--ground-cool);
}

.closing-content {
    grid-column: 1 / 13;
    text-align: center;
    position: relative;
    z-index: 2;
}

.closing-word {
    display: flex;
    justify-content: center;
    gap: clamp(1rem, 4vw, 4rem);
    margin-bottom: 3rem;
}

.closing-syllable {
    position: relative;
    display: inline-block;
    width: clamp(120px, 25vw, 300px);
    height: clamp(140px, 30vw, 360px);
}

.syllable-combined {
    font-family: 'Noto Serif KR', serif;
    font-size: clamp(6rem, 18vw, 18rem);
    font-weight: 400;
    color: var(--text-primary);
    line-height: 1;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    transition: opacity 0.8s ease;
}

.jamo {
    font-family: 'Noto Serif KR', serif;
    font-size: clamp(2.5rem, 7vw, 6rem);
    font-weight: 400;
    color: var(--text-primary);
    position: absolute;
    opacity: 0;
    transition: opacity 0.8s ease, transform 0.8s var(--stagger-ease);
}

/* 한 jamo positions */
.jamo-h { top: 0; left: 50%; transform: translate(-50%, -20px); }
.jamo-a { top: 40%; right: -10%; transform: translate(20px, -50%); }
.jamo-n { bottom: 0; left: 50%; transform: translate(-50%, 20px); }

/* 글 jamo positions */
.jamo-g { top: 0; left: 50%; transform: translate(-50%, -20px); }
.jamo-eu { top: 40%; left: 50%; transform: translate(-50%, 0) scaleX(0.8); }
.jamo-l { bottom: 0; left: 50%; transform: translate(-50%, 20px); }

/* Decomposed state */
.closing-syllable.decomposed .syllable-combined {
    opacity: 0;
}

.closing-syllable.decomposed .jamo {
    opacity: 1;
}

.closing-syllable.decomposed .jamo-h { transform: translate(-50%, 0); }
.closing-syllable.decomposed .jamo-a { transform: translate(0, -50%); }
.closing-syllable.decomposed .jamo-n { transform: translate(-50%, 0); }
.closing-syllable.decomposed .jamo-g { transform: translate(-50%, 0); }
.closing-syllable.decomposed .jamo-eu { transform: translate(-50%, 0) scaleX(1); }
.closing-syllable.decomposed .jamo-l { transform: translate(-50%, 0); }

.closing-annotation {
    font-family: 'Noto Serif KR', serif;
    font-size: var(--fs-korean);
    font-weight: 400;
    color: var(--text-secondary);
    line-height: 1.85;
    max-width: 540px;
    margin: 0 auto 1.5rem;
}

.closing-date {
    color: var(--text-tertiary);
    margin-top: 1rem;
}

/* Halftone dot field */
.halftone-field {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    background-image: radial-gradient(circle, rgba(196,186,168,0.25) 2px, transparent 2px);
    background-size: 24px 24px;
    background-position: 0 0;
}

/* =============================================
   Stagger Animation System
   ============================================= */
.stagger-item {
    opacity: 0;
    transform: translateY(24px);
}

.stagger-item.animate {
    animation: staggerIn 600ms var(--stagger-ease) forwards;
    animation-delay: calc(var(--stagger-index, 0) * var(--stagger-delay));
}

@keyframes staggerIn {
    from {
        opacity: 0;
        transform: translateY(24px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* =============================================
   Responsive Adjustments (layout only, no font breakpoints)
   ============================================= */
@media (max-width: 768px) {
    .opening-character-wrap {
        grid-column: 1 / 7;
    }

    .opening-float-char {
        grid-column: 7 / 13;
    }

    .opening-title-line {
        flex-wrap: wrap;
        gap: 0.75rem;
    }

    .history-content.left-gravity,
    .history-content.right-gravity {
        grid-column: 1 / 12;
    }

    .anatomy-content.left-gravity,
    .anatomy-content.right-gravity {
        grid-column: 1 / 12;
    }

    .gallery-content.left-gravity,
    .gallery-content.right-gravity {
        grid-column: 1 / 13;
    }

    .consonant-specimens,
    .vowel-specimens {
        padding: 0 var(--grid-gap);
    }

    .specimen-card {
        flex: 1 1 120px;
    }

    .history-timeline {
        display: none;
    }

    .float-hangul.large {
        font-size: 60vw;
    }
}

@media (max-width: 480px) {
    .opening-character-wrap {
        grid-column: 1 / 8;
    }

    .opening-float-char {
        display: none;
    }

    .site-subtitle {
        display: none;
    }

    .specimen-card {
        flex: 1 1 100%;
        max-width: 100%;
    }
}

/* =============================================
   Font Variation Animation Utility
   ============================================= */
.heading-weighted {
    font-variation-settings: 'wght' var(--heading-weight, 700);
    transition: font-variation-settings 0.3s ease;
}