:root {
    --bg-top: #08131a;
    --bg-mid: #17344a;
    --bg-bottom: #efe7d7;
    --surface: rgba(252, 248, 241, 0.92);
    --surface-soft: rgba(242, 246, 249, 0.9);
    --ink: #1b2a33;
    --muted: #60727a;
    --line: rgba(27, 42, 51, 0.12);
    --accent: #1d5c78;
    --accent-strong: #103547;
    --pendulum: #316d9a;
    --gravity: #9a5f37;
    --neutral: #6a7e86;
    --shadow: 0 28px 70px rgba(8, 19, 26, 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 14% 12%, rgba(49, 109, 154, 0.2), transparent 18%),
        radial-gradient(circle at 84% 18%, rgba(154, 95, 55, 0.18), transparent 18%),
        linear-gradient(180deg, var(--bg-top) 0%, var(--bg-mid) 18%, #eee3d2 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: 52px 52px;
    mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.72), rgba(0, 0, 0, 0.06));
}

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, 26, 0.8);
    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: #f7f0e4;
    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(247, 240, 228, 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, 1.02fr) minmax(380px, 0.98fr);
    gap: 24px;
    padding: 30px 0 8px;
}

.hero-copy,
.hero-panel,
.signal-strip,
.setup-card,
.spotlight-card,
.summary-card,
.finding-card,
.difference-card,
.metric-compare-card,
.pair-intro-card,
.note-card,
.figure-card,
.link-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);
}

.split-copy::before,
.split-copy::after {
    content: "";
    position: absolute;
    width: 240px;
    height: 240px;
    border-radius: 50%;
    filter: blur(2px);
}

.split-copy::before {
    inset: auto auto -90px -90px;
    background: radial-gradient(circle, rgba(49, 109, 154, 0.22), rgba(49, 109, 154, 0));
}

.split-copy::after {
    inset: -80px -60px auto auto;
    background: radial-gradient(circle, rgba(154, 95, 55, 0.2), rgba(154, 95, 55, 0));
}

.hero-panel {
    padding: 24px;
    border-radius: 36px;
    display: grid;
    gap: 18px;
    background: rgba(239, 246, 249, 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 {
    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, 4.7rem);
    letter-spacing: -0.05em;
}

h2 {
    font-size: clamp(1.95rem, 3vw, 3rem);
    letter-spacing: -0.03em;
}

h3 {
    font-size: clamp(1.25rem, 2vw, 1.72rem);
}

h4 {
    font-size: 1.03rem;
}

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

.hero-lead {
    margin-top: 22px;
    font-size: 1.05rem;
    line-height: 1.9;
}

.hero-actions,
.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.hero-actions {
    margin-top: 28px;
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0 18px;
    border-radius: 999px;
    font-weight: 600;
    border: 1px solid transparent;
    transition: transform 180ms ease, background 180ms ease, border-color 180ms ease;
}

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

.button-primary {
    background: linear-gradient(135deg, var(--accent-strong), var(--accent));
    color: #f9f4ed;
}

.button-secondary {
    background: rgba(255, 255, 255, 0.75);
    border-color: rgba(27, 42, 51, 0.12);
}

.hero-points,
.bullet-list,
.result-list {
    margin: 24px 0 0;
    padding-left: 18px;
    color: var(--ink);
}

.hero-points,
.bullet-list li,
.result-list li {
    line-height: 1.8;
}

.spotlight-card,
.summary-card,
.setup-card,
.finding-card,
.difference-card,
.metric-compare-card,
.pair-intro-card,
.note-card,
.link-card {
    border-radius: var(--radius-md);
}

.spotlight-card,
.difference-card,
.metric-compare-card,
.pair-intro-card,
.note-card,
.link-card {
    padding: 24px;
}

.setup-card {
    padding: 28px 26px;
}

.summary-card,
.finding-card {
    padding: 22px;
}

.dual-card {
    background: linear-gradient(135deg, rgba(18, 53, 71, 0.96), rgba(46, 85, 110, 0.88) 52%, rgba(119, 81, 58, 0.9));
    color: #f7f0e3;
}

.dual-card .card-label,
.dual-card p {
    color: rgba(247, 240, 227, 0.88);
}

.dual-card h2 {
    color: #fffaf2;
}

.strong-card {
    background: linear-gradient(180deg, rgba(22, 49, 69, 0.96), rgba(26, 71, 89, 0.9));
    color: #f6efe2;
}

.strong-card .card-label,
.strong-card p,
.strong-card li,
.strong-card dd {
    color: rgba(246, 239, 226, 0.88);
}

.strong-card h2,
.strong-card h3,
.strong-card h4,
.strong-card dt {
    color: #fff9f0;
}

.pendulum-card {
    border-color: rgba(49, 109, 154, 0.26);
}

.gravity-card {
    border-color: rgba(154, 95, 55, 0.28);
}

.neutral-card {
    border-color: rgba(106, 126, 134, 0.22);
    background: linear-gradient(180deg, rgba(252, 252, 250, 0.96), rgba(241, 244, 245, 0.92));
}

.warm-card {
    background: linear-gradient(180deg, rgba(255, 251, 245, 0.97), rgba(250, 238, 226, 0.94));
}

.stat-grid,
.summary-grid,
.system-grid,
.finding-grid,
.difference-grid,
.formula-table-shell,
.metric-compare-grid,
.pair-grid,
.takeaway-grid,
.link-board {
    display: grid;
    gap: 18px;
}

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

.stat-grid article {
    padding: 18px;
    border-radius: 24px;
}

.stat-grid span {
    display: block;
    margin-bottom: 8px;
    color: var(--muted);
    font-size: 0.86rem;
}

.stat-grid strong {
    display: block;
    font-size: 1.38rem;
    font-family: "Shippori Mincho", serif;
}

.compare-summary-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

.section-heading {
    margin-bottom: 22px;
    display: grid;
    gap: 10px;
}

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

.signal-main {
    font-size: clamp(1.5rem, 2.6vw, 2.5rem);
    line-height: 1.35;
}

.signal-sub {
    margin-top: 10px;
    max-width: 900px;
    line-height: 1.8;
}

.definition-list {
    display: grid;
    gap: 14px;
    margin: 18px 0 0;
}

.definition-list div {
    display: grid;
    gap: 4px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--line);
}

.definition-list div:last-child {
    border-bottom: 0;
    padding-bottom: 0;
}

.definition-list dt {
    font-weight: 700;
}

.definition-list dd {
    margin: 0;
}

.system-grid,
.difference-grid,
.pair-grid.two-up,
.compare-columns,
.takeaway-grid,
.link-board {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.shared-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

.metric-compare-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.metric-compare-card {
    display: grid;
    gap: 16px;
}

.formula-legend-card {
    margin-bottom: 18px;
}

.formula-table-shell {
    grid-template-columns: 1fr;
}

.formula-table-wrapper {
    overflow-x: auto;
    border-radius: var(--radius-md);
    border: 1px solid rgba(27, 42, 51, 0.1);
    background: rgba(252, 248, 241, 0.88);
    box-shadow: var(--shadow);
}

.formula-table {
    width: 100%;
    min-width: 1260px;
    border-collapse: collapse;
}

.formula-table th,
.formula-table td {
    padding: 18px 18px 20px;
    vertical-align: top;
    border-bottom: 1px solid var(--line);
}

.formula-table thead th {
    position: sticky;
    top: 0;
    z-index: 1;
    background: rgba(237, 243, 246, 0.97);
    color: var(--accent-strong);
    text-align: left;
    font-size: 0.9rem;
    letter-spacing: 0.06em;
}

.formula-table tbody th {
    width: 14%;
    color: var(--ink);
    font-family: "Shippori Mincho", serif;
    font-size: 1rem;
    text-align: left;
}

.formula-table tbody tr:last-child th,
.formula-table tbody tr:last-child td {
    border-bottom: 0;
}

.equation-inline {
    margin: 0 0 10px;
    padding: 10px 12px;
    border-radius: 14px;
    background: rgba(16, 53, 71, 0.06);
    border: 1px solid rgba(16, 53, 71, 0.1);
    color: var(--accent-strong);
    line-height: 1.68;
    overflow-wrap: anywhere;
}

.table-note {
    margin-top: 10px;
    color: var(--muted);
    line-height: 1.75;
}

.table-number-list {
    margin: 0;
    padding-left: 18px;
    color: var(--ink);
}

.table-number-list li {
    margin: 0 0 8px;
    line-height: 1.75;
}

.table-number-list li:last-child {
    margin-bottom: 0;
}

.equation-split {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
}

.equation-block {
    padding: 14px 14px 12px;
    border-radius: 18px;
    border: 1px solid rgba(16, 53, 71, 0.1);
    background: rgba(16, 53, 71, 0.05);
}

.equation-block span {
    display: block;
    margin-bottom: 8px;
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--accent-strong);
}

.equation-line {
    margin: 0;
    color: var(--accent-strong);
    line-height: 1.7;
    overflow-wrap: anywhere;
}

.pendulum-block {
    border-color: rgba(49, 109, 154, 0.18);
    background: rgba(49, 109, 154, 0.06);
}

.gravity-block {
    border-color: rgba(154, 95, 55, 0.18);
    background: rgba(154, 95, 55, 0.06);
}

.strong-card .equation-block {
    border-color: rgba(255, 255, 255, 0.14);
    background: rgba(255, 255, 255, 0.08);
}

.strong-card .equation-block span,
.strong-card .equation-line {
    color: rgba(255, 249, 240, 0.94);
}

.compare-columns {
    display: grid;
    gap: 14px;
}

.compare-columns > div {
    padding: 14px 16px;
    border-radius: 18px;
    background: rgba(16, 53, 71, 0.05);
    border: 1px solid rgba(16, 53, 71, 0.08);
}

.strong-card .compare-columns > div {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(255, 255, 255, 0.12);
}

.pair-stack {
    display: grid;
    gap: 18px;
    margin-top: 22px;
}

.pair-intro-card h3,
.note-card h3,
.link-card h3 {
    margin-bottom: 10px;
}

.split-pair-grid {
    grid-template-columns: 1.05fr 1fr 1fr;
}

.figure-card {
    border-radius: var(--radius-md);
    overflow: hidden;
}

.figure-card img {
    aspect-ratio: 16 / 10;
    object-fit: cover;
    background: rgba(255, 255, 255, 0.55);
}

.figure-card figcaption {
    padding: 18px 18px 20px;
    line-height: 1.75;
    font-size: 0.95rem;
}

.site-footer {
    margin-top: 28px;
    padding: 24px 26px;
    border-radius: 30px;
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
}

@media (max-width: 1180px) {
    .hero,
    .system-grid,
    .difference-grid,
    .metric-compare-grid,
    .split-pair-grid {
        grid-template-columns: 1fr;
    }

    .shared-grid,
    .compare-summary-grid,
    .pair-grid.two-up,
    .takeaway-grid,
    .link-board {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .equation-split {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 820px) {
    .page-shell {
        width: min(100% - 20px, 1240px);
    }

    .site-header {
        border-radius: 30px;
        padding: 16px 18px;
        align-items: flex-start;
        flex-direction: column;
    }

    .site-nav {
        justify-content: flex-start;
        gap: 12px 16px;
    }

    .hero-copy,
    .setup-card,
    .spotlight-card,
    .summary-card,
    .finding-card,
    .difference-card,
    .metric-compare-card,
    .pair-intro-card,
    .note-card,
    .link-card,
    .site-footer {
        padding: 22px 20px;
    }

    .shared-grid,
    .compare-summary-grid,
    .pair-grid.two-up,
    .stat-grid,
    .takeaway-grid,
    .link-board,
    .compare-columns,
    .equation-split {
        grid-template-columns: 1fr;
    }

    .site-footer {
        flex-direction: column;
    }
}

@media (max-width: 560px) {
    h1 {
        font-size: 2.34rem;
    }

    h2 {
        font-size: 1.7rem;
    }

    .hero-copy {
        padding: 24px 18px 28px;
    }

    .hero-panel {
        padding: 16px;
        border-radius: 28px;
    }

    .button {
        width: 100%;
    }
}