/* ============================================================
   heisei.day — Chrome Museum of the Heisei Era
   Y2K-futurism × inflated-3d × Japanese consumer chrome
   IntersectionObserver at threshold 0.2 governs entry animations.
   ============================================================ */

/* -------- Color Palette (from DESIGN.md) -------- */
:root {
    --c-bg-deep: #0a0e2a;
    --c-bg-mid: #141828;
    --c-bg-light: #1a1e32;
    --c-bg-1989: #0a0e2a;
    --c-bg-1995: #0e1a2e;
    --c-bg-2000-a: #2a3050;
    --c-bg-2000-b: #1a2040;
    --c-bg-2005: #141828;
    --c-bg-2010: #1a1e32;
    --c-bg-2019: #0a0e1e;

    --c-text: #e0e4f0;
    --c-text-soft: #8890a8;
    --c-text-mute: #8090b0;

    --c-mirror: #ffffff;
    --c-polished: #c0c8d8;
    --c-polished-2: #e0e4f0;
    --c-gunmetal: #4a5068;
    --c-gunmetal-2: #4a5068;
    --c-frame: #8090b0;

    --c-blue: #4080f0;
    --c-purple: #8050d0;
    --c-gold: #d0a040;
    --c-pink: #f04888;
    --c-deep-shadow: #1a1e3a;
    --c-mid-shadow: #4a5068;

    --f-display: 'Orbitron', 'Inter', sans-serif;
    --f-body: 'Zen Kaku Gothic New', 'Inter', sans-serif;
    --f-mono: 'Share Tech Mono', 'Space Mono', monospace;
    --f-kanji: 'Zen Maru Gothic', 'Zen Kaku Gothic New', sans-serif;

    --spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    background: var(--c-bg-deep);
    color: var(--c-text);
    font-family: var(--f-body);
    font-weight: 400;
    line-height: 1.75;
    font-size: clamp(0.95rem, 1.1vw, 1.05rem);
    overflow-x: hidden;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* -------- Section base -------- */
.section {
    position: relative;
    min-height: 100vh;
    width: 100%;
    overflow: hidden;
    padding: clamp(3rem, 8vh, 6rem) clamp(1.25rem, 5vw, 4rem);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

/* ============================================================
   CHROME TEXT — the signature visual
   ============================================================ */
.chrome-text {
    background: linear-gradient(
        180deg,
        #ffffff 0%,
        #e0e4f0 18%,
        #c0c8d8 38%,
        #8090b0 50%,
        #c0c8d8 62%,
        #e0e4f0 82%,
        #ffffff 100%
    );
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    text-shadow:
        0 1px 0 rgba(74, 80, 104, 0.6),
        0 2px 4px rgba(10, 14, 30, 0.6);
    font-family: var(--f-display);
    font-weight: 900;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    position: relative;
    display: inline-block;
}

.chrome-text-peak {
    background: linear-gradient(
        180deg,
        #ffffff 0%,
        #f04888 12%,
        #e0e4f0 28%,
        #c0c8d8 50%,
        #8050d0 70%,
        #e0e4f0 88%,
        #ffffff 100%
    );
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    text-shadow:
        0 1px 0 rgba(240, 72, 136, 0.4),
        0 2px 8px rgba(128, 80, 208, 0.4);
}

.chrome-text-mute {
    background: linear-gradient(
        180deg,
        #c0c8d8 0%,
        #8090b0 50%,
        #4a5068 100%
    );
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    text-shadow: none;
}

.chrome-text-tarnished {
    background: linear-gradient(
        180deg,
        #c0c8d8 0%,
        #8090b0 35%,
        #4a5068 50%,
        #8090b0 65%,
        #c0c8d8 100%
    );
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    font-family: var(--f-display);
    font-weight: 900;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.chrome-text-kanji {
    background: linear-gradient(
        180deg,
        #ffffff 0%,
        #c0c8d8 30%,
        #8090b0 50%,
        #c0c8d8 70%,
        #ffffff 100%
    );
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    font-family: var(--f-kanji);
    font-weight: 700;
    text-shadow: 0 1px 0 rgba(74, 80, 104, 0.7);
}

/* Shimmer overlay on chrome text */
.chrome-text::after,
.chrome-text-tarnished::after {
    content: attr(data-text);
    position: absolute;
    inset: 0;
    background: linear-gradient(
        110deg,
        transparent 30%,
        rgba(255, 255, 255, 0.55) 50%,
        transparent 70%
    );
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    background-size: 250% 100%;
    background-position: 200% 0;
    animation: chromeShimmer 6s linear infinite;
    pointer-events: none;
}

@keyframes chromeShimmer {
    from { background-position: 200% 0; }
    to { background-position: -200% 0; }
}

/* ============================================================
   META / GENERIC TYPE
   ============================================================ */
.meta-line {
    font-family: var(--f-mono);
    font-size: 0.78rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--c-text-mute);
    display: block;
}

.scroll-arrow {
    display: inline-block;
    margin-left: 0.75rem;
    color: var(--c-polished);
    animation: scrollPulse 1.8s ease-in-out infinite;
}

@keyframes scrollPulse {
    0%, 100% { transform: translateY(0); opacity: 0.7; }
    50% { transform: translateY(6px); opacity: 1; }
}

/* ============================================================
   CHROME LINE (gradient hr)
   ============================================================ */
.chrome-line {
    height: 1px;
    width: 100%;
    background: linear-gradient(
        90deg,
        transparent 0%,
        #4a5068 15%,
        #c0c8d8 50%,
        #4a5068 85%,
        transparent 100%
    );
    margin: clamp(1rem, 3vh, 2rem) 0;
}

/* ============================================================
   SECTION 1 — THE CHROME PORTAL
   ============================================================ */
.section-portal {
    background: radial-gradient(ellipse at 50% 30%, #1a2040 0%, #0a0e2a 60%, #06081a 100%);
    text-align: center;
    align-items: center;
    justify-content: center;
}

.shimmer-bg {
    position: absolute;
    inset: -20%;
    pointer-events: none;
    background: linear-gradient(
        110deg,
        transparent 35%,
        rgba(192, 200, 216, 0.08) 48%,
        rgba(255, 255, 255, 0.12) 52%,
        rgba(192, 200, 216, 0.08) 56%,
        transparent 70%
    );
    background-size: 220% 220%;
    background-position: 0% 0%;
    animation: bgShimmer 8s linear infinite;
    z-index: 0;
}

@keyframes bgShimmer {
    from { background-position: -100% -100%; }
    to { background-position: 200% 200%; }
}

.portal-grid {
    position: absolute;
    inset: 0;
    pointer-events: none;
    background-image:
        linear-gradient(rgba(128, 144, 176, 0.08) 1px, transparent 1px),
        linear-gradient(90deg, rgba(128, 144, 176, 0.08) 1px, transparent 1px);
    background-size: 60px 60px;
    mask-image: radial-gradient(ellipse at 50% 50%, rgba(0,0,0,0.9) 0%, transparent 75%);
    -webkit-mask-image: radial-gradient(ellipse at 50% 50%, rgba(0,0,0,0.9) 0%, transparent 75%);
    z-index: 0;
}

.portal-inner {
    position: relative;
    z-index: 2;
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: clamp(0.6rem, 2vh, 1.2rem);
}

.portal-meta {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    align-items: center;
    margin-bottom: 1rem;
}

.hero-title {
    font-size: clamp(3rem, 12vw, 9rem);
    line-height: 1;
    letter-spacing: 0.08em;
}

.hero-kanji {
    font-size: clamp(2.5rem, 8vw, 6rem);
    line-height: 1.1;
    margin-top: 0.5rem;
}

.hero-tagline {
    max-width: 640px;
    font-size: clamp(0.95rem, 1.2vw, 1.1rem);
    color: var(--c-text);
    margin: 1rem auto 0;
    padding: 0 1rem;
    line-height: 1.7;
}

/* Portal nav circles */
.portal-nav {
    display: flex;
    flex-wrap: wrap;
    gap: clamp(0.75rem, 2vw, 1.5rem);
    justify-content: center;
    align-items: center;
    margin: 0.5rem auto;
}

.portal-circle {
    --pc-size: clamp(72px, 9vw, 110px);
    width: var(--pc-size);
    height: var(--pc-size);
    border-radius: 50%;
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    color: var(--c-text);
    background:
        radial-gradient(circle at 35% 30%, rgba(255,255,255,0.7) 0%, rgba(192,200,216,0.2) 25%, transparent 50%),
        linear-gradient(160deg, #c0c8d8 0%, #8090b0 35%, #4a5068 70%, #1a1e3a 100%);
    box-shadow:
        inset 0 2px 3px rgba(255, 255, 255, 0.55),
        inset 0 -3px 4px rgba(10, 14, 30, 0.7),
        0 6px 18px rgba(10, 14, 30, 0.55),
        0 0 0 1px rgba(192, 200, 216, 0.4);
    transition: transform 240ms var(--spring), box-shadow 240ms ease;
    transform: scale(0);
    cursor: pointer;
}

.portal-circle.is-shown {
    transform: scale(1);
}

.portal-circle:hover,
.portal-circle:focus-visible {
    transform: scale(1.08) translateY(-2px);
    box-shadow:
        inset 0 2px 3px rgba(255, 255, 255, 0.7),
        inset 0 -3px 4px rgba(10, 14, 30, 0.7),
        0 10px 26px rgba(64, 128, 240, 0.45),
        0 0 0 1px rgba(192, 200, 216, 0.6),
        0 0 24px rgba(64, 128, 240, 0.4);
    outline: none;
}

.portal-circle.is-active {
    box-shadow:
        inset 0 2px 3px rgba(255, 255, 255, 0.7),
        inset 0 -3px 4px rgba(10, 14, 30, 0.7),
        0 6px 22px rgba(64, 128, 240, 0.55),
        0 0 0 1px rgba(192, 200, 216, 0.5),
        0 0 18px rgba(64, 128, 240, 0.5);
}

.portal-year {
    font-family: var(--f-display);
    font-weight: 700;
    font-size: clamp(0.8rem, 1.1vw, 1rem);
    letter-spacing: 0.06em;
    color: #0a0e2a;
    text-shadow:
        0 1px 0 rgba(255, 255, 255, 0.6),
        0 -1px 0 rgba(10, 14, 30, 0.4);
}

.portal-label {
    font-family: var(--f-mono);
    font-size: 0.6rem;
    letter-spacing: 0.18em;
    color: rgba(10, 14, 30, 0.7);
    margin-top: 0.15rem;
}

.portal-footer {
    margin-top: 1rem;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

/* ============================================================
   ERA PANELS — shared
   ============================================================ */
.era-panel {
    border-top: 1px solid rgba(192, 200, 216, 0.12);
    border-bottom: 1px solid rgba(74, 80, 104, 0.4);
}

.era-inner {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: clamp(1.5rem, 4vh, 3rem);
    position: relative;
    z-index: 2;
}

.era-header {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    align-items: flex-start;
}

.era-tag {
    font-family: var(--f-mono);
    font-size: 0.78rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--c-text-soft);
    padding: 0.25rem 0.75rem;
    border: 1px solid;
    border-image: linear-gradient(180deg, #c0c8d8, #4a5068, #c0c8d8) 1;
    background: rgba(10, 14, 30, 0.4);
}

.era-year {
    font-size: clamp(3rem, 8vw, 6rem);
    line-height: 1;
}

.era-title {
    font-family: var(--f-display);
    font-weight: 700;
    font-size: clamp(1.25rem, 2.2vw, 1.8rem);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--c-polished);
    margin-top: 0.25rem;
}

.era-body {
    display: grid;
    grid-template-columns: 55% 45%;
    gap: clamp(1.5rem, 3vw, 3rem);
    align-items: stretch;
}

@media (max-width: 880px) {
    .era-body {
        grid-template-columns: 1fr;
    }
}

.era-text {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding-right: clamp(0, 2vw, 1.5rem);
}

.era-lead {
    font-size: clamp(1rem, 1.3vw, 1.2rem);
    color: var(--c-text);
    line-height: 1.7;
}

.era-text p {
    color: var(--c-text);
    line-height: 1.75;
}

.era-text em {
    font-style: italic;
    color: var(--c-polished-2);
}

.era-spec {
    list-style: none;
    margin-top: 1rem;
    padding: 1rem 1.25rem;
    background: rgba(10, 14, 30, 0.4);
    border: 2px solid;
    border-image: linear-gradient(180deg, #c0c8d8, #4a5068, #c0c8d8) 1;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    font-family: var(--f-mono);
}

.era-spec li {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    font-size: 0.85rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.spec-key {
    color: var(--c-text-soft);
}

.spec-val {
    color: var(--c-polished-2);
    text-align: right;
}

.spec-flat {
    border: 1px solid var(--c-mid-shadow);
    border-image: none;
    background: rgba(10, 14, 30, 0.5);
}

/* Era feature panel container */
.era-feature {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    align-items: center;
    justify-content: center;
}

.feature-caption {
    font-family: var(--f-mono);
    font-size: 0.7rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--c-text-soft);
}

/* ============================================================
   1989 — DAWN
   ============================================================ */
.era-1989 {
    background: linear-gradient(180deg, #0a0e2a 0%, #1a1e3a 100%);
}

/* Bevel device facsimile (DAT player) */
.feature-bevel {
    width: 100%;
}

.bevel-screen {
    width: 100%;
    max-width: 420px;
    padding: 1.25rem;
    background:
        linear-gradient(180deg, #2a3050 0%, #141828 100%);
    border-top: 1px solid #c0c8d8;
    border-left: 1px solid #c0c8d8;
    border-bottom: 1px solid #4a5068;
    border-right: 1px solid #4a5068;
    box-shadow:
        inset 0 1px 0 rgba(255,255,255,0.15),
        0 8px 22px rgba(10, 14, 30, 0.7);
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.bevel-readout {
    background: #0a0e1e;
    border-top: 1px solid #4a5068;
    border-left: 1px solid #4a5068;
    border-bottom: 1px solid #c0c8d8;
    border-right: 1px solid #c0c8d8;
    padding: 0.75rem;
    font-family: var(--f-mono);
    color: var(--c-blue);
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.readout-label {
    font-size: 0.7rem;
    letter-spacing: 0.2em;
    color: var(--c-text-soft);
}

.readout-value {
    font-size: 1.4rem;
    color: #4080f0;
    text-shadow: 0 0 8px rgba(64, 128, 240, 0.5);
    letter-spacing: 0.08em;
}

.readout-bar {
    height: 6px;
    background: #1a1e3a;
    border-top: 1px solid #4a5068;
    border-left: 1px solid #4a5068;
    overflow: hidden;
}

.readout-bar > span {
    display: block;
    height: 100%;
    background: linear-gradient(90deg, #4080f0, #c0c8d8);
}

.bevel-buttons {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
}

.btn-bevel {
    width: 48px;
    height: 36px;
    background: linear-gradient(180deg, #c0c8d8 0%, #8090b0 100%);
    border-top: 1px solid #ffffff;
    border-left: 1px solid #ffffff;
    border-bottom: 1px solid #4a5068;
    border-right: 1px solid #4a5068;
    color: #1a1e3a;
    font-size: 1rem;
    cursor: pointer;
    font-family: var(--f-display);
    transition: transform 80ms ease;
}

.btn-bevel:active {
    border-top: 1px solid #4a5068;
    border-left: 1px solid #4a5068;
    border-bottom: 1px solid #ffffff;
    border-right: 1px solid #ffffff;
    background: linear-gradient(180deg, #8090b0 0%, #c0c8d8 100%);
}

/* ============================================================
   1995 — WINDOWS
   ============================================================ */
.era-1995 {
    background: #0e1a2e;
}

.feature-win95 {
    width: 100%;
}

.win95-window {
    width: 100%;
    max-width: 460px;
    background: #c0c8d8;
    border-top: 2px solid #ffffff;
    border-left: 2px solid #ffffff;
    border-bottom: 2px solid #4a5068;
    border-right: 2px solid #4a5068;
    box-shadow:
        inset 1px 1px 0 #e0e4f0,
        0 6px 20px rgba(10, 14, 30, 0.7);
    color: #0a0e2a;
    font-family: var(--f-mono);
}

.win95-titlebar {
    background: linear-gradient(90deg, #1a1e3a 0%, #4080f0 100%);
    color: #ffffff;
    padding: 0.4rem 0.6rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.win95-controls {
    display: flex;
    gap: 0.25rem;
}

.win95-ctrl {
    width: 22px;
    height: 22px;
    background: #c0c8d8;
    color: #0a0e2a;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-top: 1px solid #ffffff;
    border-left: 1px solid #ffffff;
    border-bottom: 1px solid #4a5068;
    border-right: 1px solid #4a5068;
    font-size: 0.85rem;
    line-height: 1;
}

.win95-body {
    padding: 1rem;
    background: #0a0e1e;
    color: #4080f0;
    font-size: 0.9rem;
    line-height: 1.7;
    margin: 0.5rem;
    border-top: 1px solid #4a5068;
    border-left: 1px solid #4a5068;
    border-bottom: 1px solid #ffffff;
    border-right: 1px solid #ffffff;
    min-height: 130px;
}

.win95-cursor {
    color: #c0c8d8;
    animation: blinkCursor 1s steps(2) infinite;
}

@keyframes blinkCursor {
    0%, 50% { opacity: 1; }
    50.01%, 100% { opacity: 0; }
}

.win95-bar {
    padding: 0.5rem;
    display: flex;
    justify-content: flex-end;
    gap: 0.5rem;
    background: #c0c8d8;
}

.btn-win95 {
    padding: 0.35rem 1rem;
    background: #c0c8d8;
    border-top: 2px solid #ffffff;
    border-left: 2px solid #ffffff;
    border-bottom: 2px solid #4a5068;
    border-right: 2px solid #4a5068;
    color: #0a0e2a;
    font-family: var(--f-mono);
    font-size: 0.85rem;
    letter-spacing: 0.1em;
    cursor: pointer;
    text-transform: uppercase;
}

.btn-win95:active {
    border-top: 2px solid #4a5068;
    border-left: 2px solid #4a5068;
    border-bottom: 2px solid #ffffff;
    border-right: 2px solid #ffffff;
}

/* ============================================================
   2000 — MILLENNIUM (peak chrome)
   ============================================================ */
.era-2000 {
    background:
        radial-gradient(ellipse at 80% 20%, rgba(240, 72, 136, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 10% 80%, rgba(128, 80, 208, 0.1) 0%, transparent 50%),
        linear-gradient(135deg, #2a3050 0%, #1a2040 70%);
    position: relative;
}

.era-2000::before {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(
        110deg,
        transparent 30%,
        rgba(255, 255, 255, 0.06) 50%,
        transparent 70%
    );
    background-size: 220% 100%;
    animation: bgShimmer 7s linear infinite;
    pointer-events: none;
    z-index: 1;
}

.feature-aqua {
    width: 100%;
}

.aqua-stack {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    align-items: stretch;
    width: 100%;
    max-width: 360px;
}

.btn-aqua {
    position: relative;
    border: 1px solid rgba(255, 255, 255, 0.5);
    border-radius: 999px;
    padding: 1rem 1.5rem;
    font-family: var(--f-display);
    font-weight: 700;
    font-size: 1rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: #ffffff;
    cursor: pointer;
    overflow: hidden;
    box-shadow:
        inset 0 1px 0 rgba(255, 255, 255, 0.7),
        inset 0 -8px 16px rgba(10, 14, 30, 0.4),
        0 6px 20px rgba(10, 14, 30, 0.5);
    transition: transform 200ms var(--spring), box-shadow 200ms ease;
}

.btn-aqua::before {
    content: "";
    position: absolute;
    inset: 2px 2px auto 2px;
    height: 45%;
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.6) 0%, rgba(255, 255, 255, 0) 100%);
    border-radius: 999px 999px 999px 999px / 999px 999px 60px 60px;
    pointer-events: none;
}

.btn-aqua-pink {
    background: linear-gradient(180deg, #f04888 0%, #c01868 60%, #80103a 100%);
    text-shadow: 0 1px 2px rgba(80, 16, 58, 0.7);
}

.btn-aqua-blue {
    background: linear-gradient(180deg, #4080f0 0%, #2050b0 60%, #103080 100%);
    text-shadow: 0 1px 2px rgba(16, 48, 128, 0.7);
}

.btn-aqua-purple {
    background: linear-gradient(180deg, #a070e0 0%, #6030b0 60%, #401880 100%);
    text-shadow: 0 1px 2px rgba(64, 24, 128, 0.7);
}

.btn-aqua:hover {
    transform: translateY(-2px) scale(1.02);
    box-shadow:
        inset 0 1px 0 rgba(255, 255, 255, 0.8),
        inset 0 -8px 16px rgba(10, 14, 30, 0.4),
        0 12px 28px rgba(10, 14, 30, 0.6);
}

/* ============================================================
   2005 — DIGITAL (glass)
   ============================================================ */
.era-2005 {
    background:
        radial-gradient(circle at 70% 20%, rgba(64, 128, 240, 0.08) 0%, transparent 50%),
        #141828;
}

.feature-glass {
    width: 100%;
}

.glass-card {
    width: 100%;
    max-width: 420px;
    padding: 1.5rem 1.6rem;
    background:
        linear-gradient(135deg, rgba(192, 200, 216, 0.12) 0%, rgba(74, 80, 104, 0.18) 100%);
    backdrop-filter: blur(14px) saturate(140%);
    -webkit-backdrop-filter: blur(14px) saturate(140%);
    border: 1px solid rgba(192, 200, 216, 0.35);
    box-shadow:
        inset 0 1px 0 rgba(255, 255, 255, 0.25),
        0 12px 32px rgba(10, 14, 30, 0.55);
    color: var(--c-text);
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    border-radius: 4px;
}

.glass-tag {
    font-family: var(--f-mono);
    font-size: 0.7rem;
    letter-spacing: 0.22em;
    color: var(--c-text-soft);
    text-transform: uppercase;
}

.glass-headline {
    font-family: var(--f-kanji);
    font-weight: 700;
    font-size: 2.4rem;
    color: var(--c-polished-2);
    letter-spacing: 0.05em;
    line-height: 1;
    text-shadow: 0 2px 12px rgba(64, 128, 240, 0.35);
}

.glass-body {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--c-text);
}

.glass-meter {
    margin-top: 0.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.glass-meter-label {
    font-family: var(--f-mono);
    font-size: 0.7rem;
    letter-spacing: 0.2em;
    color: var(--c-text-soft);
}

.glass-meter-bar {
    height: 4px;
    background: rgba(192, 200, 216, 0.2);
    border-radius: 999px;
    overflow: hidden;
}

.glass-meter-bar > span {
    display: block;
    height: 100%;
    background: linear-gradient(90deg, #4080f0 0%, #c0c8d8 100%);
    border-radius: 999px;
    box-shadow: 0 0 10px rgba(64, 128, 240, 0.6);
}

/* ============================================================
   2010 — SHIFT (frosted, muted)
   ============================================================ */
.era-2010 {
    background: #1a1e32;
}

.feature-frost {
    width: 100%;
}

.frost-card {
    width: 100%;
    max-width: 420px;
    padding: 1.5rem 1.6rem;
    background: rgba(192, 200, 216, 0.06);
    backdrop-filter: blur(20px) saturate(120%);
    -webkit-backdrop-filter: blur(20px) saturate(120%);
    border: 1px solid rgba(192, 200, 216, 0.2);
    box-shadow:
        inset 0 1px 0 rgba(255, 255, 255, 0.15),
        0 8px 24px rgba(10, 14, 30, 0.5);
    color: var(--c-text);
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.frost-tag {
    font-family: var(--f-mono);
    font-size: 0.7rem;
    letter-spacing: 0.22em;
    color: var(--c-text-soft);
    text-transform: uppercase;
}

.frost-headline {
    font-family: var(--f-display);
    font-weight: 700;
    font-size: 1.4rem;
    color: var(--c-polished);
    letter-spacing: 0.08em;
}

.frost-body {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--c-text-soft);
}

.frost-rows {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    margin-top: 0.5rem;
    padding-top: 0.75rem;
    border-top: 1px solid rgba(192, 200, 216, 0.15);
}

.frost-row {
    display: flex;
    justify-content: space-between;
    font-family: var(--f-mono);
    font-size: 0.78rem;
    letter-spacing: 0.15em;
    color: var(--c-text-soft);
    text-transform: uppercase;
}

.frost-row span:last-child {
    color: var(--c-polished);
}

/* ============================================================
   2019 — FAREWELL (flat)
   ============================================================ */
.era-2019 {
    background: #0a0e1e;
}

.feature-flat {
    width: 100%;
}

.flat-card {
    width: 100%;
    max-width: 420px;
    padding: 2rem 1.75rem;
    background: #141828;
    border: 1px solid #4a5068;
    color: var(--c-text);
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.flat-tag {
    font-family: var(--f-mono);
    font-size: 0.78rem;
    letter-spacing: 0.2em;
    color: var(--c-text-soft);
}

.flat-headline {
    font-family: var(--f-kanji);
    font-weight: 700;
    font-size: 2rem;
    color: var(--c-text);
    letter-spacing: 0.05em;
    line-height: 1.1;
}

.flat-body {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--c-text-soft);
}

.btn-flat {
    margin-top: 0.5rem;
    align-self: flex-start;
    padding: 0.7rem 1.4rem;
    background: #4080f0;
    color: #ffffff;
    border: none;
    font-family: var(--f-display);
    font-weight: 700;
    font-size: 0.85rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    cursor: pointer;
    transition: background 160ms ease;
}

.btn-flat:hover {
    background: #2060c8;
}

/* ============================================================
   SECTION 8 — REFLECTION
   ============================================================ */
.section-reflection {
    background: radial-gradient(ellipse at 50% 40%, #1a1e32 0%, #0a0e1e 75%);
    align-items: center;
    text-align: center;
    padding: clamp(4rem, 10vh, 8rem) 1.5rem;
}

.reflection-inner {
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
}

.reflection-stack {
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    line-height: 1;
}

.reflection-title {
    font-size: clamp(2.2rem, 7vw, 5rem);
    letter-spacing: 0.08em;
    line-height: 1;
}

.reflection-line {
    width: 70%;
    height: 1px;
    margin: 0.4rem 0;
    background: linear-gradient(
        90deg,
        transparent 0%,
        rgba(255, 255, 255, 0.25) 50%,
        transparent 100%
    );
}

.reflection-mirror {
    font-size: clamp(2.2rem, 7vw, 5rem);
    letter-spacing: 0.08em;
    line-height: 1;
    transform: scaleY(-1);
    -webkit-mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.35) 0%, rgba(0, 0, 0, 0) 75%);
    mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.35) 0%, rgba(0, 0, 0, 0) 75%);
    opacity: 0.7;
}

.reflection-quote {
    font-family: var(--f-body);
    font-weight: 500;
    font-size: clamp(1.05rem, 1.4vw, 1.25rem);
    line-height: 1.7;
    color: var(--c-text-soft);
    max-width: 640px;
    margin: 0 auto;
    font-style: italic;
}

.reflection-meta {
    margin-top: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    align-items: center;
}

/* ============================================================
   ENTRY ANIMATIONS — IntersectionObserver classes
   ============================================================ */
.era-text,
.era-feature,
.era-header,
.reflection-stack,
.reflection-quote,
.reflection-meta {
    opacity: 0;
    transition: opacity 800ms ease, transform 800ms ease;
    will-change: opacity, transform;
}

/* 1989-1995 slide up, hard ease-out */
.era-1989 .era-text,
.era-1989 .era-feature,
.era-1989 .era-header,
.era-1995 .era-text,
.era-1995 .era-feature,
.era-1995 .era-header {
    transform: translateY(30px);
    transition: opacity 400ms ease-out, transform 400ms ease-out;
}

.era-1989.is-visible .era-text,
.era-1989.is-visible .era-feature,
.era-1989.is-visible .era-header,
.era-1995.is-visible .era-text,
.era-1995.is-visible .era-feature,
.era-1995.is-visible .era-header {
    opacity: 1;
    transform: translateY(0);
}

/* 2000 scale + flash */
.era-2000 .era-text,
.era-2000 .era-feature,
.era-2000 .era-header {
    transform: scale(0.92);
    transition: opacity 600ms ease-out, transform 600ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

.era-2000.is-visible .era-text,
.era-2000.is-visible .era-feature,
.era-2000.is-visible .era-header {
    opacity: 1;
    transform: scale(1);
}

.era-2000.is-visible::after {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse at 50% 50%, rgba(240, 72, 136, 0.18) 0%, transparent 60%);
    pointer-events: none;
    z-index: 1;
    animation: y2kFlash 900ms ease-out forwards;
}

@keyframes y2kFlash {
    0% { opacity: 0.9; }
    60% { opacity: 0.6; }
    100% { opacity: 0; }
}

/* 2005-2010 glass blur */
.era-2005 .era-text,
.era-2005 .era-feature,
.era-2005 .era-header,
.era-2010 .era-text,
.era-2010 .era-feature,
.era-2010 .era-header {
    filter: blur(8px);
    transition: opacity 700ms ease, filter 700ms ease;
}

.era-2005.is-visible .era-text,
.era-2005.is-visible .era-feature,
.era-2005.is-visible .era-header,
.era-2010.is-visible .era-text,
.era-2010.is-visible .era-feature,
.era-2010.is-visible .era-header {
    opacity: 1;
    filter: blur(0);
}

/* 2019 plain fade */
.era-2019 .era-text,
.era-2019 .era-feature,
.era-2019 .era-header {
    transform: none;
    transition: opacity 500ms ease;
}

.era-2019.is-visible .era-text,
.era-2019.is-visible .era-feature,
.era-2019.is-visible .era-header {
    opacity: 1;
}

/* Reflection slow fade */
.section-reflection .reflection-stack,
.section-reflection .reflection-quote,
.section-reflection .reflection-meta {
    transform: translateY(20px);
    transition: opacity 1500ms ease, transform 1500ms ease;
}

.section-reflection.is-visible .reflection-stack,
.section-reflection.is-visible .reflection-quote,
.section-reflection.is-visible .reflection-meta {
    opacity: 1;
    transform: translateY(0);
}

/* Hero entry */
.hero-title,
.hero-kanji,
.hero-tagline {
    opacity: 0;
    transform: scale(1.05);
    transition: opacity 600ms ease-out, transform 600ms ease-out;
}

.section-portal.is-loaded .hero-title {
    opacity: 1;
    transform: scale(1);
}

.section-portal.is-loaded .hero-kanji {
    opacity: 1;
    transform: scale(1);
    transition-delay: 300ms;
}

.section-portal.is-loaded .hero-tagline {
    opacity: 1;
    transform: scale(1);
    transition-delay: 500ms;
}

/* ============================================================
   REDUCED MOTION
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 250ms !important;
    }

    .shimmer-bg,
    .chrome-text::after,
    .chrome-text-tarnished::after,
    .era-2000::before {
        display: none !important;
    }

    .portal-circle {
        transform: scale(1) !important;
    }

    .hero-title,
    .hero-kanji,
    .hero-tagline {
        opacity: 1;
        transform: none;
    }
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 640px) {
    .portal-circle {
        --pc-size: 64px;
    }

    .portal-label {
        display: none;
    }

    .era-spec li {
        font-size: 0.78rem;
    }

    .glass-headline,
    .flat-headline {
        font-size: 1.6rem;
    }
}