:root {
    --bg-top: #08131b;
    --bg-mid: #173247;
    --bg-bottom: #efe5d6;
    --surface: rgba(252, 248, 242, 0.9);
    --surface-soft: rgba(237, 243, 248, 0.86);
    --surface-strong: rgba(255, 252, 247, 0.96);
    --ink: #1b2733;
    --muted: #62717b;
    --line: rgba(27, 39, 51, 0.12);
    --accent: #244a63;
    --accent-strong: #163145;
    --accent-soft: #be7a4c;
    --accent-warm: #8a4c24;
    --shadow: 0 28px 70px rgba(8, 19, 27, 0.18);
    --radius-lg: 38px;
    --radius-md: 28px;
    --radius-sm: 20px;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    color: var(--ink);
    font-family: "IBM Plex Sans JP", sans-serif;
    background:
        radial-gradient(circle at 12% 16%, rgba(190, 122, 76, 0.22), transparent 20%),
        radial-gradient(circle at 84% 10%, rgba(36, 74, 99, 0.24), transparent 18%),
        linear-gradient(180deg, var(--bg-top) 0%, var(--bg-mid) 18%, #f0e7da 18.1%, var(--bg-bottom) 100%);
    min-height: 100vh;
}

body::before {
    content: "";
    position: fixed;
    inset: 0;
    pointer-events: none;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
    background-size: 48px 48px;
    mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.78), rgba(0, 0, 0, 0.08));
}

a {
    color: inherit;
    text-decoration: none;
}

img {
    display: block;
    width: 100%;
    height: auto;
}

main {
    display: flex;
    flex-direction: column;
    gap: 28px;
}

main section[id] {
    scroll-margin-top: 118px;
}

.page-shell {
    width: min(1240px, calc(100% - 32px));
    margin: 0 auto;
    padding-bottom: 88px;
}

.site-header {
    position: sticky;
    top: 14px;
    z-index: 20;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    margin: 18px 0 24px;
    padding: 16px 22px;
    border-radius: 999px;
    background: rgba(8, 19, 27, 0.78);
    border: 1px solid rgba(255, 255, 255, 0.12);
    backdrop-filter: blur(18px);
    box-shadow: 0 16px 38px rgba(0, 0, 0, 0.22);
}

.brand {
    color: #f6efe2;
    font-family: "Shippori Mincho", serif;
    font-size: 1.14rem;
    letter-spacing: 0.1em;
}

.site-nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 18px;
    color: rgba(246, 239, 226, 0.84);
    font-size: 0.95rem;
}

.site-nav a,
.footer-link {
    transition: color 180ms ease, opacity 180ms ease;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.site-nav a.is-active,
.footer-link:hover,
.footer-link:focus-visible {
    color: #ffffff;
}

.section,
.signal-strip,
.site-footer {
    opacity: 0;
    transform: translateY(26px);
    transition: opacity 520ms ease, transform 520ms ease;
}

.reveal.is-visible,
.site-footer.is-visible {
    opacity: 1;
    transform: translateY(0);
}

.hero {
    display: grid;
    grid-template-columns: minmax(0, 1.03fr) minmax(360px, 0.97fr);
    gap: 24px;
    padding: 30px 0 8px;
}

.hero-copy,
.hero-panel,
.signal-strip,
.setup-card,
.finding-card,
.experiment-card,
.figure-card,
.link-card,
.spotlight-card,
.summary-card,
.site-footer,
.stat-grid article {
    border: 1px solid rgba(255, 255, 255, 0.62);
    background: var(--surface);
    box-shadow: var(--shadow);
    backdrop-filter: blur(16px);
}

.hero-copy {
    position: relative;
    overflow: hidden;
    padding: 42px 34px 40px 38px;
    border-radius: var(--radius-lg);
}

.hero-copy::after {
    content: "";
    position: absolute;
    inset: auto -58px -108px auto;
    width: 320px;
    height: 320px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(190, 122, 76, 0.34), rgba(190, 122, 76, 0));
}

.hero-panel {
    padding: 24px;
    border-radius: 36px;
    display: grid;
    gap: 18px;
    background: rgba(240, 246, 251, 0.18);
}

.eyebrow,
.card-label,
.signal-kicker {
    margin: 0 0 12px;
    color: var(--accent-strong);
    font-size: 0.82rem;
    font-weight: 700;
    letter-spacing: 0.22em;
    text-transform: uppercase;
}

h1,
h2,
h3,
h4,
.brand,
.signal-main,
.equation-chip {
    font-family: "Shippori Mincho", serif;
}

h1,
h2,
h3,
h4,
.brand {
    line-height: 1.15;
}

h1,
h2,
h3,
h4,
p {
    margin: 0;
}

h1 {
    font-size: clamp(2.7rem, 5vw, 4.8rem);
    letter-spacing: -0.05em;
}

h2 {
    font-size: clamp(1.9rem, 3vw, 3rem);
    letter-spacing: -0.03em;
}

h3 {
    font-size: clamp(1.25rem, 2vw, 1.75rem);
}

h4 {
    font-size: 1.04rem;
}

.hero-lead,
.section-heading p,
.spotlight-card p,
.summary-card p,
.setup-card p,
.setup-card dd,
.finding-card p,
.experiment-card p,
.figure-card figcaption,
.signal-sub,
.site-footer p,
.stat-grid p,
.section-note {
    color: var(--muted);
}

.hero-lead {
    margin-top: 20px;
    font-size: 1.03rem;
    line-height: 1.88;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    margin-top: 26px;
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0 20px;
    border-radius: 999px;
    font-weight: 600;
    transition: transform 180ms ease, background-color 180ms ease, color 180ms ease;
}

.button:hover,
.button:focus-visible {
    transform: translateY(-1px);
}

.button-primary {
    color: #f7f2ea;
    background: linear-gradient(135deg, var(--accent) 0%, #315e7f 100%);
}

.button-secondary {
    color: var(--accent-strong);
    background: rgba(255, 252, 247, 0.92);
    border: 1px solid rgba(22, 49, 69, 0.14);
}

.hero-points {
    margin: 26px 0 0;
    padding-left: 20px;
    display: grid;
    gap: 10px;
    line-height: 1.72;
}

.hero-points li::marker,
.result-list li::marker {
    color: var(--accent-soft);
}

.spotlight-card,
.summary-card,
.setup-card,
.finding-card,
.experiment-card,
.link-card {
    border-radius: var(--radius-md);
}

.spotlight-card,
.summary-card,
.setup-card,
.finding-card,
.experiment-card,
.link-card,
.figure-card {
    padding: 24px;
}

.strong-card {
    background: var(--surface-strong);
}

.warm-card {
    background: linear-gradient(180deg, rgba(255, 249, 239, 0.98), rgba(250, 239, 226, 0.92));
}

.spotlight-card h2 {
    margin-bottom: 14px;
}

.stat-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
}

.stat-grid article {
    padding: 18px 18px 16px;
    border-radius: 22px;
}

.stat-grid span {
    display: block;
    margin-bottom: 8px;
    color: var(--muted);
    font-size: 0.83rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.stat-grid strong {
    display: block;
    margin-bottom: 6px;
    font-size: 1.5rem;
}

.summary-grid,
.finding-grid,
.takeaway-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
}

.summary-card h3,
.finding-card h3,
.experiment-card h3,
.link-card h3,
.setup-card h3 {
    margin-bottom: 10px;
}

.signal-strip {
    padding: 26px 28px;
    border-radius: 30px;
}

.signal-kicker {
    margin-bottom: 8px;
}

.signal-main {
    font-size: clamp(1.5rem, 2vw, 2rem);
    line-height: 1.3;
}

.signal-sub {
    margin-top: 10px;
    max-width: 860px;
    line-height: 1.76;
}

.section {
    display: grid;
    gap: 24px;
}

.section-heading {
    display: grid;
    gap: 12px;
    max-width: 860px;
}

.section-heading p {
    line-height: 1.82;
}

#overview .section-heading h2 {
    color: #f4ede2;
}

#overview .section-heading .eyebrow {
    color: rgba(214, 228, 239, 0.72);
}

#overview .section-heading p:not(.eyebrow) {
    color: rgba(234, 241, 246, 0.84);
}

#findings .section-heading h2 {
    color: #53311f;
}

#findings .section-heading .eyebrow {
    color: #a16339;
}

#findings .section-heading p:not(.eyebrow) {
    color: rgba(83, 49, 31, 0.78);
}

.overview-grid {
    display: grid;
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
    gap: 18px;
}

.definition-list {
    display: grid;
    gap: 12px;
    margin: 14px 0 0;
}

.definition-list div {
    display: grid;
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 12px;
    padding: 11px 0;
    border-bottom: 1px solid var(--line);
}

.definition-list div:last-child {
    border-bottom: none;
}

.definition-list dt {
    color: var(--accent-strong);
    font-weight: 700;
}

.region-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
    margin-top: 16px;
}

.section-note {
    margin-top: 14px;
    line-height: 1.75;
}

.experiment-stack {
    display: grid;
    gap: 18px;
}

.result-list {
    margin: 14px 0 0;
    padding-left: 18px;
    display: grid;
    gap: 9px;
    line-height: 1.72;
}

.result-list.compact {
    margin-top: 12px;
    gap: 8px;
}

.equation-chip {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 44px;
    margin-top: 16px;
    padding: 0 16px;
    border-radius: 999px;
    color: var(--accent-strong);
    background: rgba(255, 255, 255, 0.72);
    border: 1px solid rgba(22, 49, 69, 0.12);
}

.figure-grid {
    display: grid;
    gap: 18px;
}

.figure-grid.two-up {
    grid-template-columns: 1fr;
}

.figure-card {
    border-radius: var(--radius-md);
    background: rgba(251, 249, 244, 0.94);
}

.figure-card img {
    border-radius: 18px;
    background: #0e1620;
    border: 1px solid rgba(8, 19, 27, 0.08);
}

.figure-card figcaption {
    margin-top: 14px;
    line-height: 1.72;
}

.link-board {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
}

.link-card {
    display: grid;
    gap: 10px;
    transition: transform 180ms ease, border-color 180ms ease;
}

.link-card:hover,
.link-card:focus-visible {
    transform: translateY(-2px);
    border-color: rgba(36, 74, 99, 0.26);
}

.site-footer {
    display: grid;
    gap: 14px;
    margin-top: 30px;
    padding: 26px 28px;
    border-radius: 30px;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: 18px;
}

@media (max-width: 1080px) {
    .hero,
    .overview-grid,
    .summary-grid,
    .takeaway-grid,
    .link-board {
        grid-template-columns: 1fr;
    }

    .figure-grid.two-up,
    .region-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 820px) {
    .page-shell {
        width: min(100%, calc(100% - 20px));
    }

    .site-header {
        padding: 14px 18px;
        border-radius: 28px;
    }

    .site-nav {
        gap: 12px 16px;
        font-size: 0.91rem;
    }

    .hero-copy,
    .hero-panel,
    .spotlight-card,
    .summary-card,
    .setup-card,
    .finding-card,
    .experiment-card,
    .figure-card,
    .link-card,
    .signal-strip,
    .site-footer {
        padding: 20px;
    }

    .stat-grid {
        grid-template-columns: 1fr;
    }

    .definition-list div {
        grid-template-columns: 1fr;
        gap: 6px;
    }
}

@media (max-width: 640px) {
    body {
        background:
            radial-gradient(circle at 16% 12%, rgba(190, 122, 76, 0.16), transparent 22%),
            linear-gradient(180deg, var(--bg-top) 0%, var(--bg-mid) 19%, #f2eadd 19.1%, var(--bg-bottom) 100%);
    }

    .site-header {
        position: static;
        margin-top: 12px;
        flex-direction: column;
        align-items: flex-start;
    }

    h1 {
        font-size: 2.35rem;
    }

    h2 {
        font-size: 1.85rem;
    }

    .hero-actions {
        flex-direction: column;
        align-items: stretch;
    }

    .button {
        width: 100%;
    }
}